// ----------------------------------------------------------------------------
// You can set the following variables before loading this script:

/*global netdataNoDygraphs           *//* boolean,  disable dygraph charts
 *                                                  (default: false) */
/*global netdataNoSparklines         *//* boolean,  disable sparkline charts
 *                                                  (default: false) */
/*global netdataNoPeitys             *//* boolean,  disable peity charts
 *                                                  (default: false) */
/*global netdataNoGoogleCharts       *//* boolean,  disable google charts
 *                                                  (default: false) */
/*global netdataNoMorris             *//* boolean,  disable morris charts
 *                                                  (default: false) */
/*global netdataNoEasyPieChart       *//* boolean,  disable easypiechart charts
 *                                                  (default: false) */
/*global netdataNoGauge              *//* boolean,  disable gauge.js charts
 *                                                  (default: false) */
/*global netdataNoD3                 *//* boolean,  disable d3 charts
 *                                                  (default: false) */
/*global netdataNoC3                 *//* boolean,  disable c3 charts
 *                                                  (default: false) */
/*global netdataNoBootstrap          *//* boolean,  disable bootstrap - disables help too
 *                                                  (default: false) */
/*global netdataDontStart            *//* boolean,  do not start the thread to process the charts
 *                                                  (default: false) */
/*global netdataErrorCallback        *//* function, callback to be called when the dashboard encounters an error
 *                                                  (default: null) */
/*global netdataRegistry:true        *//* boolean,  use the netdata registry
 *                                                  (default: false) */
/*global netdataNoRegistry           *//* boolean,  included only for compatibility with existing custom dashboard
 *                                                  (obsolete - do not use this any more) */
/*global netdataRegistryCallback     *//* function, callback that will be invoked with one param: the URLs from the registry
 *                                                  (default: null) */
/*global netdataShowHelp:true        *//* boolean,  disable charts help
 *                                                  (default: true) */
/*global netdataShowAlarms:true      *//* boolean,  enable alarms checks and notifications
 *                                                  (default: false) */
/*global netdataRegistryAfterMs:true *//* ms,       delay registry use at started
 *                                                  (default: 1500) */
/*global netdataCallback             *//* function, callback to be called when netdata is ready to start
 *                                                  (default: null)
 *                                                  netdata will be running while this is called
 *                                                  (call NETDATA.pause to stop it) */
/*global netdataPrepCallback         *//* function, callback to be called before netdata does anything else
 *                                                  (default: null) */
/*global netdataServer               *//* string,   the URL of the netdata server to use
 *                                                  (default: the URL the page is hosted at) */
/*global netdataServerStatic         *//* string,   the URL of the netdata server to use for static files
 *                                                  (default: netdataServer) */
/*global netdataSnapshotData         *//* object,   a netdata snapshot loaded
 *                                                  (default: null) */

// ----------------------------------------------------------------------------
// global namespace

var NETDATA = window.NETDATA || {};

(function(window, document, $, undefined) {
    // ------------------------------------------------------------------------
    // compatibility fixes

    // fix IE issue with console
    if(!window.console) { window.console = { log: function(){} }; }

    // if string.endsWith is not defined, define it
    if(typeof String.prototype.endsWith !== 'function') {
        String.prototype.endsWith = function(s) {
            if(s.length > this.length) return false;
            return this.slice(-s.length) === s;
        };
    }

    // if string.startsWith is not defined, define it
    if(typeof String.prototype.startsWith !== 'function') {
        String.prototype.startsWith = function(s) {
            if(s.length > this.length) return false;
            return this.slice(s.length) === s;
        };
    }

    NETDATA.name2id = function(s) {
        return s
            .replace(/ /g, '_')
            .replace(/\(/g, '_')
            .replace(/\)/g, '_')
            .replace(/\./g, '_')
            .replace(/\//g, '_');
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Detect the netdata server

    // http://stackoverflow.com/questions/984510/what-is-my-script-src-url
    // http://stackoverflow.com/questions/6941533/get-protocol-domain-and-port-from-url
    NETDATA._scriptSource = function() {
        var script = null;

        if(typeof document.currentScript !== 'undefined') {
            script = document.currentScript;
        }
        else {
            var all_scripts = document.getElementsByTagName('script');
            script = all_scripts[all_scripts.length - 1];
        }

        if (typeof script.getAttribute.length !== 'undefined')
            script = script.src;
        else
            script = script.getAttribute('src', -1);

        return script;
    };

    if(typeof netdataServer !== 'undefined')
        NETDATA.serverDefault = netdataServer;
    else {
        var s = NETDATA._scriptSource();
        if(s) NETDATA.serverDefault = s.replace(/\/dashboard.js(\?.*)*$/g, "");
        else {
            console.log('WARNING: Cannot detect the URL of the netdata server.');
            NETDATA.serverDefault = null;
        }
    }

    if(NETDATA.serverDefault === null)
        NETDATA.serverDefault = '';
    else if(NETDATA.serverDefault.slice(-1) !== '/')
        NETDATA.serverDefault += '/';

    if(typeof netdataServerStatic !== 'undefined' && netdataServerStatic !== null && netdataServerStatic !== '') {
        NETDATA.serverStatic = netdataServerStatic;
        if(NETDATA.serverStatic.slice(-1) !== '/')
            NETDATA.serverStatic += '/';
    }
    else {
        NETDATA.serverStatic = NETDATA.serverDefault;
    }


    // default URLs for all the external files we need
    // make them RELATIVE so that the whole thing can also be
    // installed under a web server
    NETDATA.jQuery              = NETDATA.serverStatic + 'lib/jquery-2.2.4.min.js';
    NETDATA.peity_js            = NETDATA.serverStatic + 'lib/jquery.peity-3.2.0.min.js';
    NETDATA.sparkline_js        = NETDATA.serverStatic + 'lib/jquery.sparkline-2.1.2.min.js';
    NETDATA.easypiechart_js     = NETDATA.serverStatic + 'lib/jquery.easypiechart-97b5824.min.js';
    NETDATA.gauge_js            = NETDATA.serverStatic + 'lib/gauge-1.3.2.min.js';
    NETDATA.dygraph_js          = NETDATA.serverStatic + 'lib/dygraph-combined-dd74404.js';
    NETDATA.dygraph_smooth_js   = NETDATA.serverStatic + 'lib/dygraph-smooth-plotter-dd74404.js';
    NETDATA.raphael_js          = NETDATA.serverStatic + 'lib/raphael-2.2.4-min.js';
    NETDATA.c3_js               = NETDATA.serverStatic + 'lib/c3-0.4.11.min.js';
    NETDATA.c3_css              = NETDATA.serverStatic + 'css/c3-0.4.11.min.css';
    NETDATA.d3_js               = NETDATA.serverStatic + 'lib/d3-3.5.17.min.js';
    NETDATA.morris_js           = NETDATA.serverStatic + 'lib/morris-0.5.1.min.js';
    NETDATA.morris_css          = NETDATA.serverStatic + 'css/morris-0.5.1.css';
    NETDATA.google_js           = 'https://www.google.com/jsapi';

    NETDATA.themes = {
        white: {
            bootstrap_css: NETDATA.serverStatic + 'css/bootstrap-3.3.7.css',
            dashboard_css: NETDATA.serverStatic + 'dashboard.css?v20171208-1',
            background: '#FFFFFF',
            foreground: '#000000',
            grid: '#F0F0F0',
            axis: '#F0F0F0',
            highlight: '#F5F5F5',
            colors: [   '#3366CC', '#DC3912',   '#109618', '#FF9900',   '#990099', '#DD4477',
                        '#3B3EAC', '#66AA00',   '#0099C6', '#B82E2E',   '#AAAA11', '#5574A6',
                        '#994499', '#22AA99',   '#6633CC', '#E67300',   '#316395', '#8B0707',
                        '#329262', '#3B3EAC' ],
            easypiechart_track: '#f0f0f0',
            easypiechart_scale: '#dfe0e0',
            gauge_pointer: '#C0C0C0',
            gauge_stroke: '#F0F0F0',
            gauge_gradient: false
        },
        slate: {
            bootstrap_css: NETDATA.serverStatic + 'css/bootstrap-slate-flat-3.3.7.css?v20161229-1',
            dashboard_css: NETDATA.serverStatic + 'dashboard.slate.css?v20171208-1',
            background: '#272b30',
            foreground: '#C8C8C8',
            grid: '#283236',
            axis: '#283236',
            highlight: '#383838',
/*          colors: [   '#55bb33', '#ff2222',   '#0099C6', '#faa11b',   '#adbce0', '#DDDD00',
                        '#4178ba', '#f58122',   '#a5cc39', '#f58667',   '#f5ef89', '#cf93c0',
                        '#a5d18a', '#b8539d',   '#3954a3', '#c8a9cf',   '#c7de8a', '#fad20a',
                        '#a6a479', '#a66da8' ],
*/
            colors: [   '#66AA00', '#FE3912',   '#3366CC', '#D66300',   '#0099C6', '#DDDD00',
                        '#5054e6', '#EE9911',   '#BB44CC', '#e45757',   '#ef0aef', '#CC7700',
                        '#22AA99', '#109618',   '#905bfd', '#f54882',   '#4381bf', '#ff3737',
                        '#329262', '#3B3EFF' ],
            easypiechart_track: '#373b40',
            easypiechart_scale: '#373b40',
            gauge_pointer: '#474b50',
            gauge_stroke: '#373b40',
            gauge_gradient: false
        }
    };

    if(typeof netdataTheme !== 'undefined' && typeof NETDATA.themes[netdataTheme] !== 'undefined')
        NETDATA.themes.current = NETDATA.themes[netdataTheme];
    else
        NETDATA.themes.current = NETDATA.themes.white;

    NETDATA.colors = NETDATA.themes.current.colors;

    // these are the colors Google Charts are using
    // we have them here to attempt emulate their look and feel on the other chart libraries
    // http://there4.io/2012/05/02/google-chart-color-list/
    //NETDATA.colors        = [ '#3366CC', '#DC3912', '#FF9900', '#109618', '#990099', '#3B3EAC', '#0099C6',
    //                      '#DD4477', '#66AA00', '#B82E2E', '#316395', '#994499', '#22AA99', '#AAAA11',
    //                      '#6633CC', '#E67300', '#8B0707', '#329262', '#5574A6', '#3B3EAC' ];

    // an alternative set
    // http://www.mulinblog.com/a-color-palette-optimized-for-data-visualization/
    //                         (blue)     (red)      (orange)   (green)    (pink)     (brown)    (purple)   (yellow)   (gray)
    //NETDATA.colors        = [ '#5DA5DA', '#F15854', '#FAA43A', '#60BD68', '#F17CB0', '#B2912F', '#B276B2', '#DECF3F', '#4D4D4D' ];

    if(typeof netdataSnapshotData === 'undefined')
        netdataSnapshotData = null;

    if(typeof netdataShowHelp === 'undefined')
        netdataShowHelp = true;

    if(typeof netdataShowAlarms === 'undefined')
        netdataShowAlarms = false;

    if(typeof netdataRegistryAfterMs !== 'number' || netdataRegistryAfterMs < 0)
        netdataRegistryAfterMs = 1500;

    if(typeof netdataRegistry === 'undefined') {
        // backward compatibility
        netdataRegistry = (typeof netdataNoRegistry !== 'undefined' && netdataNoRegistry === false);
    }
    if(netdataRegistry === false && typeof netdataRegistryCallback === 'function')
        netdataRegistry = true;


    // ----------------------------------------------------------------------------------------------------------------
    // detect if this is probably a slow device

    var isSlowDeviceResult = undefined;
    var isSlowDevice = function() {
        if(isSlowDeviceResult !== undefined)
            return isSlowDeviceResult;

        try {
            var ua = navigator.userAgent.toLowerCase();

            var iOS = /ipad|iphone|ipod/.test(ua) && !window.MSStream;
            var android = /android/.test(ua) && !window.MSStream;
            isSlowDeviceResult = (iOS === true || android === true);
        }
        catch (e) {
            isSlowDeviceResult = false;
        }

        return isSlowDeviceResult;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // the defaults for all charts

    // if the user does not specify any of these, the following will be used

    NETDATA.chartDefaults = {
        width: '100%',                  // the chart width - can be null
        height: '100%',                 // the chart height - can be null
        min_width: null,                // the chart minimum width - can be null
        library: 'dygraph',             // the graphing library to use
        method: 'average',              // the grouping method
        before: 0,                      // panning
        after: -600,                    // panning
        pixels_per_point: 1,            // the detail of the chart
        fill_luminance: 0.8             // luminance of colors in solid areas
    };

    // ----------------------------------------------------------------------------------------------------------------
    // global options

    NETDATA.options = {
        pauseCallback: null,            // a callback when we are really paused

        pause: false,                   // when enabled we don't auto-refresh the charts

        targets: null,                  // an array of all the state objects that are
                                        // currently active (independently of their
                                        // viewport visibility)

        updated_dom: true,              // when true, the DOM has been updated with
                                        // new elements we have to check.

        auto_refresher_fast_weight: 0,  // this is the current time in ms, spent
                                        // rendering charts continuously.
                                        // used with .current.fast_render_timeframe

        page_is_visible: true,          // when true, this page is visible

        auto_refresher_stop_until: 0,   // timestamp in ms - used internally, to stop the
                                        // auto-refresher for some time (when a chart is
                                        // performing pan or zoom, we need to stop refreshing
                                        // all other charts, to have the maximum speed for
                                        // rendering the chart that is panned or zoomed).
                                        // Used with .current.global_pan_sync_time

        on_scroll_refresher_stop_until: 0, // timestamp in ms - used to stop evaluating
                                        // charts for some time, after a page scroll

        last_page_resize: Date.now(),   // the timestamp of the last resize request

        last_page_scroll: 0,            // the timestamp the last time the page was scrolled

        browser_timezone: 'unknown',    // timezone detected by javascript
        server_timezone: 'unknown',     // timezone reported by the server

        force_data_points: 0,           // force the number of points to be returned for charts
        fake_chart_rendering: false,    // when set to true, the dashboard will download data but will not render the charts

        passive_events: null,           // true if the browser supports passive events

        // the current profile
        // we may have many...
        current: {
            units: 'auto',              // can be 'auto' or 'original'
            temperature: 'celsius',     // can be 'celsius' or 'fahrenheit'
            seconds_as_time: true,      // show seconds as DDd:HH:MM:SS ?
            timezone: 'default',        // the timezone to use, or 'default'
            user_set_server_timezone: 'default', // as set by the user on the dashboard

            legend_toolbox: true,       // show the legend toolbox on charts
            resize_charts: true,        // show the resize handler on charts

            pixels_per_point: isSlowDevice()?5:1, // the minimum pixels per point for all charts
                                        // increase this to speed javascript up
                                        // each chart library has its own limit too
                                        // the max of this and the chart library is used
                                        // the final is calculated every time, so a change
                                        // here will have immediate effect on the next chart
                                        // update

            idle_between_charts: 100,   // ms - how much time to wait between chart updates

            fast_render_timeframe: 200, // ms - render continuously until this time of continuous
                                        // rendering has been reached
                                        // this setting is used to make it render e.g. 10
                                        // charts at once, sleep idle_between_charts time
                                        // and continue for another 10 charts.

            idle_between_loops: 500,    // ms - if all charts have been updated, wait this
                                        // time before starting again.

            idle_parallel_loops: 100,   // ms - the time between parallel refresher updates

            idle_lost_focus: 500,       // ms - when the window does not have focus, check
                                        // if focus has been regained, every this time

            global_pan_sync_time: 300,  // ms - when you pan or zoom a chart, the background
                                        // auto-refreshing of charts is paused for this amount
                                        // of time

            sync_selection_delay: 400,  // ms - when you pan or zoom a chart, wait this amount
                                        // of time before setting up synchronized selections
                                        // on hover.

            sync_selection: true,       // enable or disable selection sync

            pan_and_zoom_delay: 50,     // when panning or zooming, how ofter to update the chart

            sync_pan_and_zoom: true,    // enable or disable pan and zoom sync

            pan_and_zoom_data_padding: true, // fetch more data for the master chart when panning or zooming

            update_only_visible: true,  // enable or disable visibility management

            parallel_refresher: (isSlowDevice() === false), // enable parallel refresh of charts

            concurrent_refreshes: true, // when parallel_refresher is enabled, sync also the charts

            destroy_on_hide: (isSlowDevice() === true), // destroy charts when they are not visible

            show_help: netdataShowHelp, // when enabled the charts will show some help
            show_help_delay_show_ms: 500,
            show_help_delay_hide_ms: 0,

            eliminate_zero_dimensions: true, // do not show dimensions with just zeros

            stop_updates_when_focus_is_lost: true, // boolean - shall we stop auto-refreshes when document does not have user focus
            stop_updates_while_resizing: 1000,  // ms - time to stop auto-refreshes while resizing the charts

            double_click_speed: 500,    // ms - time between clicks / taps to detect double click/tap

            smooth_plot: (isSlowDevice() === false), // enable smooth plot, where possible

            color_fill_opacity_line: 1.0,
            color_fill_opacity_area: 0.2,
            color_fill_opacity_stacked: 0.8,

            pan_and_zoom_factor: 0.25,      // the increment when panning and zooming with the toolbox
            pan_and_zoom_factor_multiplier_control: 2.0,
            pan_and_zoom_factor_multiplier_shift: 3.0,
            pan_and_zoom_factor_multiplier_alt: 4.0,

            abort_ajax_on_scroll: false,            // kill pending ajax page scroll
            async_on_scroll: false,                 // sync/async onscroll handler
            onscroll_worker_duration_threshold: 30, // time in ms, for async scroll handler

            retries_on_data_failures: 3, // how many retries to make if we can't fetch chart data from the server

            setOptionCallback: function() { }
        },

        debug: {
            show_boxes:         false,
            main_loop:          false,
            focus:              false,
            visibility:         false,
            chart_data_url:     false,
            chart_errors:       true, // FIXME: remember to set it to false before merging
            chart_timing:       false,
            chart_calls:        false,
            libraries:          false,
            dygraph:            false,
            globalSelectionSync:false,
            globalPanAndZoom:   false
        }
    };

    NETDATA.statistics = {
        refreshes_total: 0,
        refreshes_active: 0,
        refreshes_active_max: 0
    };


    // ----------------------------------------------------------------------------------------------------------------

    NETDATA.timeout = {
        // by default, these are just wrappers to setTimeout() / clearTimeout()

        step: function(callback) {
            return window.setTimeout(callback, 1000 / 60);
        },

        set: function(callback, delay) {
            return window.setTimeout(callback, delay);
        },

        clear: function(id) {
            return window.clearTimeout(id);
        },

        init: function() {
            var custom = true;

            if(window.requestAnimationFrame) {
                this.step = function(callback) {
                    return window.requestAnimationFrame(callback);
                };

                this.clear = function(handle) {
                    return window.cancelAnimationFrame(handle.value);
                };
            }
            else if(window.webkitRequestAnimationFrame) {
                this.step = function(callback) {
                    return window.webkitRequestAnimationFrame(callback);
                };

                if(window.webkitCancelAnimationFrame) {
                    this.clear = function (handle) {
                        return window.webkitCancelAnimationFrame(handle.value);
                    };
                }
                else if(window.webkitCancelRequestAnimationFrame) {
                    this.clear = function (handle) {
                        return window.webkitCancelRequestAnimationFrame(handle.value);
                    };
                }
            }
            else if(window.mozRequestAnimationFrame) {
                this.step = function(callback) {
                    return window.mozRequestAnimationFrame(callback);
                };

                this.clear = function(handle) {
                    return window.mozCancelRequestAnimationFrame(handle.value);
                };
            }
            else if(window.oRequestAnimationFrame) {
                this.step = function(callback) {
                    return window.oRequestAnimationFrame(callback);
                };

                this.clear = function(handle) {
                    return window.oCancelRequestAnimationFrame(handle.value);
                };
            }
            else if(window.msRequestAnimationFrame) {
                this.step = function(callback) {
                    return window.msRequestAnimationFrame(callback);
                };

                this.clear = function(handle) {
                    return window.msCancelRequestAnimationFrame(handle.value);
                };
            }
            else
                custom = false;


            if(custom === true) {
                // we have installed custom .step() / .clear() functions
                // overwrite the .set() too

                this.set = function(callback, delay) {
                    var that = this;

                    var start = Date.now(),
                        handle = new Object();

                    function loop() {
                        var current = Date.now(),
                            delta = current - start;

                        if(delta >= delay) {
                            callback.call();
                        }
                        else {
                            handle.value = that.step(loop);
                        }
                    }

                    handle.value = that.step(loop);
                    return handle;
                };
            }
        }
    };

    NETDATA.timeout.init();


    // ----------------------------------------------------------------------------------------------------------------
    // local storage options

    NETDATA.localStorage = {
        default: {},
        current: {},
        callback: {} // only used for resetting back to defaults
    };

    NETDATA.localStorageTested = -1;
    NETDATA.localStorageTest = function() {
        if(NETDATA.localStorageTested !== -1)
            return NETDATA.localStorageTested;

        if(typeof Storage !== "undefined" && typeof localStorage === 'object') {
            var test = 'test';
            try {
                localStorage.setItem(test, test);
                localStorage.removeItem(test);
                NETDATA.localStorageTested = true;
            }
            catch (e) {
                NETDATA.localStorageTested = false;
            }
        }
        else
            NETDATA.localStorageTested = false;

        return NETDATA.localStorageTested;
    };

    NETDATA.localStorageGet = function(key, def, callback) {
        var ret = def;

        if(typeof NETDATA.localStorage.default[key.toString()] === 'undefined') {
            NETDATA.localStorage.default[key.toString()] = def;
            NETDATA.localStorage.callback[key.toString()] = callback;
        }

        if(NETDATA.localStorageTest() === true) {
            try {
                // console.log('localStorage: loading "' + key.toString() + '"');
                ret = localStorage.getItem(key.toString());
                // console.log('netdata loaded: ' + key.toString() + ' = ' + ret.toString());
                if(ret === null || ret === 'undefined') {
                    // console.log('localStorage: cannot load it, saving "' + key.toString() + '" with value "' + JSON.stringify(def) + '"');
                    localStorage.setItem(key.toString(), JSON.stringify(def));
                    ret = def;
                }
                else {
                    // console.log('localStorage: got "' + key.toString() + '" with value "' + ret + '"');
                    ret = JSON.parse(ret);
                    // console.log('localStorage: loaded "' + key.toString() + '" as value ' + ret + ' of type ' + typeof(ret));
                }
            }
            catch(error) {
                console.log('localStorage: failed to read "' + key.toString() + '", using default: "' + def.toString() + '"');
                ret = def;
            }
        }

        if(typeof ret === 'undefined' || ret === 'undefined') {
            console.log('localStorage: LOADED UNDEFINED "' + key.toString() + '" as value ' + ret + ' of type ' + typeof(ret));
            ret = def;
        }

        NETDATA.localStorage.current[key.toString()] = ret;
        return ret;
    };

    NETDATA.localStorageSet = function(key, value, callback) {
        if(typeof value === 'undefined' || value === 'undefined') {
            console.log('localStorage: ATTEMPT TO SET UNDEFINED "' + key.toString() + '" as value ' + value + ' of type ' + typeof(value));
        }

        if(typeof NETDATA.localStorage.default[key.toString()] === 'undefined') {
            NETDATA.localStorage.default[key.toString()] = value;
            NETDATA.localStorage.current[key.toString()] = value;
            NETDATA.localStorage.callback[key.toString()] = callback;
        }

        if(NETDATA.localStorageTest() === true) {
            // console.log('localStorage: saving "' + key.toString() + '" with value "' + JSON.stringify(value) + '"');
            try {
                localStorage.setItem(key.toString(), JSON.stringify(value));
            }
            catch(e) {
                console.log('localStorage: failed to save "' + key.toString() + '" with value: "' + value.toString() + '"');
            }
        }

        NETDATA.localStorage.current[key.toString()] = value;
        return value;
    };

    NETDATA.localStorageGetRecursive = function(obj, prefix, callback) {
        var keys = Object.keys(obj);
        var len = keys.length;
        while(len--) {
            var i = keys[len];

            if(typeof obj[i] === 'object') {
                //console.log('object ' + prefix + '.' + i.toString());
                NETDATA.localStorageGetRecursive(obj[i], prefix + '.' + i.toString(), callback);
                continue;
            }

            obj[i] = NETDATA.localStorageGet(prefix + '.' + i.toString(), obj[i], callback);
        }
    };

    NETDATA.setOption = function(key, value) {
        if(key.toString() === 'setOptionCallback') {
            if(typeof NETDATA.options.current.setOptionCallback === 'function') {
                NETDATA.options.current[key.toString()] = value;
                NETDATA.options.current.setOptionCallback();
            }
        }
        else if(NETDATA.options.current[key.toString()] !== value) {
            var name = 'options.' + key.toString();

            if(typeof NETDATA.localStorage.default[name.toString()] === 'undefined')
                console.log('localStorage: setOption() on unsaved option: "' + name.toString() + '", value: ' + value);

            //console.log(NETDATA.localStorage);
            //console.log('setOption: setting "' + key.toString() + '" to "' + value + '" of type ' + typeof(value) + ' original type ' + typeof(NETDATA.options.current[key.toString()]));
            //console.log(NETDATA.options);
            NETDATA.options.current[key.toString()] = NETDATA.localStorageSet(name.toString(), value, null);

            if(typeof NETDATA.options.current.setOptionCallback === 'function')
                NETDATA.options.current.setOptionCallback();
        }

        return true;
    };

    NETDATA.getOption = function(key) {
        return NETDATA.options.current[key.toString()];
    };

    // read settings from local storage
    NETDATA.localStorageGetRecursive(NETDATA.options.current, 'options', null);

    // always start with this option enabled.
    NETDATA.setOption('stop_updates_when_focus_is_lost', true);

    NETDATA.resetOptions = function() {
        var keys = Object.keys(NETDATA.localStorage.default);
        var len = keys.length;
        while(len--) {
            var i = keys[len];
            var a = i.split('.');

            if(a[0] === 'options') {
                if(a[1] === 'setOptionCallback') continue;
                if(typeof NETDATA.localStorage.default[i] === 'undefined') continue;
                if(NETDATA.options.current[i] === NETDATA.localStorage.default[i]) continue;

                NETDATA.setOption(a[1], NETDATA.localStorage.default[i]);
            }
            else if(a[0] === 'chart_heights') {
                if(typeof NETDATA.localStorage.callback[i] === 'function' && typeof NETDATA.localStorage.default[i] !== 'undefined') {
                    NETDATA.localStorage.callback[i](NETDATA.localStorage.default[i]);
                }
            }
        }

        NETDATA.dateTime.init(NETDATA.options.current.timezone);
    };

    // ----------------------------------------------------------------------------------------------------------------

    if(NETDATA.options.debug.main_loop === true)
        console.log('welcome to NETDATA');

    NETDATA.onresizeCallback = null;
    NETDATA.onresize = function() {
        NETDATA.options.last_page_resize = Date.now();
        NETDATA.onscroll();

        if(typeof NETDATA.onresizeCallback === 'function')
            NETDATA.onresizeCallback();
    };

    NETDATA.abort_all_refreshes = function() {
        var targets = NETDATA.options.targets;
        var len = targets.length;

        while (len--) {
            if (targets[len].fetching_data === true) {
                if (typeof targets[len].xhr !== 'undefined') {
                    targets[len].xhr.abort();
                    targets[len].running = false;
                    targets[len].fetching_data = false;
                }
            }
        }
    };

    NETDATA.onscroll_start_delay = function() {
        NETDATA.options.last_page_scroll = Date.now();

        NETDATA.options.on_scroll_refresher_stop_until =
            NETDATA.options.last_page_scroll
            + ((NETDATA.options.current.async_on_scroll === true) ? 1000 : 0);
    };

    NETDATA.onscroll_end_delay = function() {
        NETDATA.options.on_scroll_refresher_stop_until =
            Date.now()
            + ((NETDATA.options.current.async_on_scroll === true) ? NETDATA.options.current.onscroll_worker_duration_threshold : 0);
    };

    NETDATA.onscroll_updater_timeout_id = undefined;
    NETDATA.onscroll_updater = function() {
        if(NETDATA.options.targets === null) return;

        //var start = Date.now();

        // console.log('onscroll_updater() begin');

        NETDATA.globalSelectionSync.stop();

        // when the user scrolls he sees that we have
        // hidden all the not-visible charts
        // using this little function we try to switch
        // the charts back to visible quickly

        if(NETDATA.options.abort_ajax_on_scroll === true)
            NETDATA.abort_all_refreshes();

        if(NETDATA.options.current.parallel_refresher === false) {
            var targets = NETDATA.options.targets;
            var len = targets.length;

            while (len--)
                targets[len].isVisible();
        }

        //var end = Date.now();
        //var dt = end - start;
        // console.log('count = ' + targets.length + ', average = ' + Math.round(dt / targets.length).toString() + ', dt = ' + dt);

        NETDATA.onscroll_end_delay();
    };

    NETDATA.scrollUp = false;
    NETDATA.scrollY = window.scrollY;
    NETDATA.onscroll = function() {
        //console.log('onscroll() begin');

        NETDATA.onscroll_start_delay();
        NETDATA.chartRefresherReschedule();

        NETDATA.scrollUp = (window.scrollY > NETDATA.scrollY);
        NETDATA.scrollY = window.scrollY;

        if(NETDATA.onscroll_updater_timeout_id)
            NETDATA.timeout.clear(NETDATA.onscroll_updater_timeout_id);

        NETDATA.onscroll_updater_timeout_id = NETDATA.timeout.set(NETDATA.onscroll_updater, 0);
        //console.log('onscroll() end');
    };

    NETDATA.supportsPassiveEvents = function() {
        if(NETDATA.options.passive_events === null) {
            var supportsPassive = false;
            try {
                var opts = Object.defineProperty({}, 'passive', {
                    get: function () {
                        supportsPassive = true;
                    }
                });
                window.addEventListener("test", null, opts);
            } catch (e) {
                console.log('browser does not support passive events');
            }

            NETDATA.options.passive_events = supportsPassive;
        }

        // console.log('passive ' + NETDATA.options.passive_events);
        return NETDATA.options.passive_events;
    };

    window.addEventListener('resize', NETDATA.onresize, NETDATA.supportsPassiveEvents() ? { passive: true } : false);
    window.addEventListener('scroll', NETDATA.onscroll, NETDATA.supportsPassiveEvents() ? { passive: true } : false);
    // window.onresize = NETDATA.onresize;
    // window.onscroll = NETDATA.onscroll;

    // ----------------------------------------------------------------------------------------------------------------
    // Error Handling

    NETDATA.errorCodes = {
        100: { message: "Cannot load chart library", alert: true },
        101: { message: "Cannot load jQuery", alert: true },
        402: { message: "Chart library not found", alert: false },
        403: { message: "Chart library not enabled/is failed", alert: false },
        404: { message: "Chart not found", alert: false },
        405: { message: "Cannot download charts index from server", alert: true },
        406: { message: "Invalid charts index downloaded from server", alert: true },
        407: { message: "Cannot HELLO netdata server", alert: false },
        408: { message: "Netdata servers sent invalid response to HELLO", alert: false },
        409: { message: "Cannot ACCESS netdata registry", alert: false },
        410: { message: "Netdata registry ACCESS failed", alert: false },
        411: { message: "Netdata registry server send invalid response to DELETE ", alert: false },
        412: { message: "Netdata registry DELETE failed", alert: false },
        413: { message: "Netdata registry server send invalid response to SWITCH ", alert: false },
        414: { message: "Netdata registry SWITCH failed", alert: false },
        415: { message: "Netdata alarms download failed", alert: false },
        416: { message: "Netdata alarms log download failed", alert: false },
        417: { message: "Netdata registry server send invalid response to SEARCH ", alert: false },
        418: { message: "Netdata registry SEARCH failed", alert: false }
    };
    NETDATA.errorLast = {
        code: 0,
        message: "",
        datetime: 0
    };

    NETDATA.error = function(code, msg) {
        NETDATA.errorLast.code = code;
        NETDATA.errorLast.message = msg;
        NETDATA.errorLast.datetime = Date.now();

        console.log("ERROR " + code + ": " + NETDATA.errorCodes[code].message + ": " + msg);

        var ret = true;
        if(typeof netdataErrorCallback === 'function') {
           ret = netdataErrorCallback('system', code, msg);
        }

        if(ret && NETDATA.errorCodes[code].alert)
            alert("ERROR " + code + ": " + NETDATA.errorCodes[code].message + ": " + msg);
    };

    NETDATA.errorReset = function() {
        NETDATA.errorLast.code = 0;
        NETDATA.errorLast.message = "You are doing fine!";
        NETDATA.errorLast.datetime = 0;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // fast numbers formatting

    NETDATA.fastNumberFormat = {
        formatters_fixed: [],
        formatters_zero_based: [],

        // this is the fastest and the preferred
        getIntlNumberFormat: function(min, max) {
            var key = max;
            if(min === max) {
                if(typeof this.formatters_fixed[key] === 'undefined')
                    this.formatters_fixed[key] = new Intl.NumberFormat(undefined, {
                        // style: 'decimal',
                        // minimumIntegerDigits: 1,
                        // minimumSignificantDigits: 1,
                        // maximumSignificantDigits: 1,
                        useGrouping: true,
                        minimumFractionDigits: min,
                        maximumFractionDigits: max
                    });

                return this.formatters_fixed[key];
            }
            else if(min === 0) {
                if(typeof this.formatters_zero_based[key] === 'undefined')
                    this.formatters_zero_based[key] = new Intl.NumberFormat(undefined, {
                        // style: 'decimal',
                        // minimumIntegerDigits: 1,
                        // minimumSignificantDigits: 1,
                        // maximumSignificantDigits: 1,
                        useGrouping: true,
                        minimumFractionDigits: min,
                        maximumFractionDigits: max
                    });

                return this.formatters_zero_based[key];
            }
            else {
                // this is never used
                // it is added just for completeness
                return new Intl.NumberFormat(undefined, {
                    // style: 'decimal',
                    // minimumIntegerDigits: 1,
                    // minimumSignificantDigits: 1,
                    // maximumSignificantDigits: 1,
                    useGrouping: true,
                    minimumFractionDigits: min,
                    maximumFractionDigits: max
                });
            }
        },

        // this respects locale
        getLocaleString: function(min, max) {
            var key = max;
            if(min === max) {
                if(typeof this.formatters_fixed[key] === 'undefined')
                    this.formatters_fixed[key] = {
                        format: function (value) {
                            return value.toLocaleString(undefined, {
                                // style: 'decimal',
                                // minimumIntegerDigits: 1,
                                // minimumSignificantDigits: 1,
                                // maximumSignificantDigits: 1,
                                useGrouping: true,
                                minimumFractionDigits: min,
                                maximumFractionDigits: max
                            });
                        }
                    };

                return this.formatters_fixed[key];
            }
            else if(min === 0) {
                if(typeof this.formatters_zero_based[key] === 'undefined')
                    this.formatters_zero_based[key] = {
                        format: function (value) {
                            return value.toLocaleString(undefined, {
                                // style: 'decimal',
                                // minimumIntegerDigits: 1,
                                // minimumSignificantDigits: 1,
                                // maximumSignificantDigits: 1,
                                useGrouping: true,
                                minimumFractionDigits: min,
                                maximumFractionDigits: max
                            });
                        }
                    };

                return this.formatters_zero_based[key];
            }
            else {
                return {
                    format: function (value) {
                        return value.toLocaleString(undefined, {
                            // style: 'decimal',
                            // minimumIntegerDigits: 1,
                            // minimumSignificantDigits: 1,
                            // maximumSignificantDigits: 1,
                            useGrouping: true,
                            minimumFractionDigits: min,
                            maximumFractionDigits: max
                        });
                    }
                };
            }
        },

        // the fallback
        getFixed: function(min, max) {
            var key = max;
            if(min === max) {
                if(typeof this.formatters_fixed[key] === 'undefined')
                    this.formatters_fixed[key] = {
                        format: function (value) {
                            if(value === 0) return "0";
                            return value.toFixed(max);
                        }
                    };

                return this.formatters_fixed[key];
            }
            else if(min === 0) {
                if(typeof this.formatters_zero_based[key] === 'undefined')
                    this.formatters_zero_based[key] = {
                        format: function (value) {
                            if(value === 0) return "0";
                            return value.toFixed(max);
                        }
                    };

                return this.formatters_zero_based[key];
            }
            else {
                return {
                    format: function (value) {
                        if(value === 0) return "0";
                        return value.toFixed(max);
                    }
                };
            }
        },

        testIntlNumberFormat: function() {
            var value = 1.12345;
            var e1 = "1.12", e2 = "1,12";
            var s = "";

            try {
                var x = new Intl.NumberFormat(undefined, {
                    useGrouping: true,
                    minimumFractionDigits: 2,
                    maximumFractionDigits: 2
                });

                s = x.format(value);
            }
            catch(e) {
                s = "";
            }

            // console.log('NumberFormat: ', s);
            return (s === e1 || s === e2);
        },

        testLocaleString: function() {
            var value = 1.12345;
            var e1 = "1.12", e2 = "1,12";
            var s = "";

            try {
                s = value.toLocaleString(undefined, {
                    useGrouping: true,
                    minimumFractionDigits: 2,
                    maximumFractionDigits: 2
                });
            }
            catch(e) {
                s = "";
            }

            // console.log('localeString: ', s);
            return (s === e1 || s === e2);
        },

        // on first run we decide which formatter to use
        get: function(min, max) {
            if(this.testIntlNumberFormat()) {
                // console.log('numberformat');
                this.get = this.getIntlNumberFormat;
            }
            else if(this.testLocaleString()) {
                // console.log('localestring');
                this.get = this.getLocaleString;
            }
            else {
                // console.log('fixed');
                this.get = this.getFixed;
            }
            return this.get(min, max);
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // element data attributes

    NETDATA.dataAttribute = function(element, attribute, def) {
        var key = 'data-' + attribute.toString();
        if(element.hasAttribute(key) === true) {
            var data = element.getAttribute(key);

            if(data === 'true') return true;
            if(data === 'false') return false;
            if(data === 'null') return null;

            // Only convert to a number if it doesn't change the string
            if(data === +data + '') return +data;

            if(/^(?:\{[\w\W]*\}|\[[\w\W]*\])$/.test(data))
                return JSON.parse(data);

            return data;
        }
        else return def;
    };

    NETDATA.dataAttributeBoolean = function(element, attribute, def) {
        var value = NETDATA.dataAttribute(element, attribute, def);

        if(value === true || value === false)
            return value;

        if(typeof(value) === 'string') {
            if(value === 'yes' || value === 'on')
                return true;

            if(value === '' || value === 'no' || value === 'off' || value === 'null')
                return false;

            return def;
        }

        if(typeof(value) === 'number')
            return value !== 0;

        return def;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // commonMin & commonMax

    NETDATA.commonMin = {
        keys: {},
        latest: {},

        globalReset: function() {
            this.keys = {};
            this.latest = {};
        },

        get: function(state) {
            if(typeof state.tmp.__commonMin === 'undefined') {
                // get the commonMin setting
                state.tmp.__commonMin = NETDATA.dataAttribute(state.element, 'common-min', null);
            }

            var min = state.data.min;
            var name = state.tmp.__commonMin;

            if(name === null) {
                // we don't need commonMin
                //state.log('no need for commonMin');
                return min;
            }

            var t = this.keys[name];
            if(typeof t === 'undefined') {
                // add our commonMin
                this.keys[name] = {};
                t = this.keys[name];
            }

            var uuid = state.uuid;
            if(typeof t[uuid] !== 'undefined') {
                if(t[uuid] === min) {
                    //state.log('commonMin ' + state.tmp.__commonMin + ' not changed: ' + this.latest[name]);
                    return this.latest[name];
                }
                else if(min < this.latest[name]) {
                    //state.log('commonMin ' + state.tmp.__commonMin + ' increased: ' + min);
                    t[uuid] = min;
                    this.latest[name] = min;
                    return min;
                }
            }

            // add our min
            t[uuid] = min;

            // find the common min
            var m = min;
            for(var i in t)
                if(t.hasOwnProperty(i) && t[i] < m) m = t[i];

            //state.log('commonMin ' + state.tmp.__commonMin + ' updated: ' + m);
            this.latest[name] = m;
            return m;
        }
    };

    NETDATA.commonMax = {
        keys: {},
        latest: {},

        globalReset: function() {
            this.keys = {};
            this.latest = {};
        },

        get: function(state) {
            if(typeof state.tmp.__commonMax === 'undefined') {
                // get the commonMax setting
                state.tmp.__commonMax = NETDATA.dataAttribute(state.element, 'common-max', null);
            }

            var max = state.data.max;
            var name = state.tmp.__commonMax;

            if(name === null) {
                // we don't need commonMax
                //state.log('no need for commonMax');
                return max;
            }

            var t = this.keys[name];
            if(typeof t === 'undefined') {
                // add our commonMax
                this.keys[name] = {};
                t = this.keys[name];
            }

            var uuid = state.uuid;
            if(typeof t[uuid] !== 'undefined') {
                if(t[uuid] === max) {
                    //state.log('commonMax ' + state.tmp.__commonMax + ' not changed: ' + this.latest[name]);
                    return this.latest[name];
                }
                else if(max > this.latest[name]) {
                    //state.log('commonMax ' + state.tmp.__commonMax + ' increased: ' + max);
                    t[uuid] = max;
                    this.latest[name] = max;
                    return max;
                }
            }

            // add our max
            t[uuid] = max;

            // find the common max
            var m = max;
            for(var i in t)
                if(t.hasOwnProperty(i) && t[i] > m) m = t[i];

            //state.log('commonMax ' + state.tmp.__commonMax + ' updated: ' + m);
            this.latest[name] = m;
            return m;
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Chart Registry

    // When multiple charts need the same chart, we avoid downloading it
    // multiple times (and having it in browser memory multiple time)
    // by using this registry.

    // Every time we download a chart definition, we save it here with .add()
    // Then we try to get it back with .get(). If that fails, we download it.

    NETDATA.fixHost = function(host) {
        while(host.slice(-1) === '/')
            host = host.substring(0, host.length - 1);

        return host;
    };

    NETDATA.chartRegistry = {
        charts: {},

        globalReset: function() {
            this.charts = {};
        },

        add: function(host, id, data) {
            if(typeof this.charts[host] === 'undefined')
                this.charts[host] = {};

            //console.log('added ' + host + '/' + id);
            this.charts[host][id] = data;
        },

        get: function(host, id) {
            if(typeof this.charts[host] === 'undefined')
                return null;

            if(typeof this.charts[host][id] === 'undefined')
                return null;

            //console.log('cached ' + host + '/' + id);
            return this.charts[host][id];
        },

        downloadAll: function(host, callback) {
            host = NETDATA.fixHost(host);

            var self = this;

            function got_data(h, data, callback) {
                if(data !== null) {
                    self.charts[h] = data.charts;

                    // update the server timezone in our options
                    if(typeof data.timezone === 'string')
                        NETDATA.options.server_timezone = data.timezone;
                }
                else NETDATA.error(406, h + '/api/v1/charts');

                if(typeof callback === 'function')
                    callback(data);
            }

            if(netdataSnapshotData !== null) {
                got_data(host, netdataSnapshotData.charts, callback);
            }
            else {
                $.ajax({
                    url: host + '/api/v1/charts',
                    async: true,
                    cache: false,
                    xhrFields: {withCredentials: true} // required for the cookie
                })
                    .done(function (data) {
                        got_data(host, data, callback);
                    })
                    .fail(function () {
                        NETDATA.error(405, host + '/api/v1/charts');

                        if (typeof callback === 'function')
                            callback(null);
                    });
            }
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Global Pan and Zoom on charts

    // Using this structure are synchronize all the charts, so that
    // when you pan or zoom one, all others are automatically refreshed
    // to the same timespan.

    NETDATA.globalPanAndZoom = {
        seq: 0,                 // timestamp ms
                                // every time a chart is panned or zoomed
                                // we set the timestamp here
                                // then we use it as a sequence number
                                // to find if other charts are synchronized
                                // to this time-range

        master: null,           // the master chart (state), to which all others
                                // are synchronized

        force_before_ms: null,  // the timespan to sync all other charts
        force_after_ms: null,

        callback: null,

        globalReset: function() {
            this.clearMaster();
            this.seq = 0;
            this.master = null;
            this.force_after_ms = null;
            this.force_before_ms = null;
            this.callback = null;
        },

        delay: function() {
            if(NETDATA.options.debug.globalPanAndZoom === true)
                console.log('globalPanAndZoom.delay()');

            NETDATA.options.auto_refresher_stop_until = Date.now() + NETDATA.options.current.global_pan_sync_time;
        },

        // set a new master
        setMaster: function(state, after, before) {
            this.delay();

            if(NETDATA.options.current.sync_pan_and_zoom === false)
                return;

            if(this.master === null) {
                if(NETDATA.options.debug.globalPanAndZoom === true)
                    console.log('globalPanAndZoom.setMaster(' + state.id + ', ' + after + ', ' + before + ') SET MASTER');
            }
            else if(this.master !== state) {
                if(NETDATA.options.debug.globalPanAndZoom === true)
                    console.log('globalPanAndZoom.setMaster(' + state.id + ', ' + after + ', ' + before + ') CHANGED MASTER');

                this.master.resetChart(true, true);
            }

            var now = Date.now();
            this.master = state;
            this.seq = now;
            this.force_after_ms = after;
            this.force_before_ms = before;

            if(typeof this.callback === 'function')
                this.callback(true, after, before);
        },

        // clear the master
        clearMaster: function() {
            if(NETDATA.options.debug.globalPanAndZoom === true)
                console.log('globalPanAndZoom.clearMaster()');

            if(this.master !== null) {
                var st = this.master;
                this.master = null;
                st.resetChart();
            }

            this.master = null;
            this.seq = 0;
            this.force_after_ms = null;
            this.force_before_ms = null;
            NETDATA.options.auto_refresher_stop_until = 0;

            if(typeof this.callback === 'function')
                this.callback(false, 0, 0);
        },

        // is the given state the master of the global
        // pan and zoom sync?
        isMaster: function(state) {
            return (this.master === state);
        },

        // are we currently have a global pan and zoom sync?
        isActive: function() {
            return (this.master !== null && this.force_before_ms !== null && this.force_after_ms !== null && this.seq !== 0);
        },

        // check if a chart, other than the master
        // needs to be refreshed, due to the global pan and zoom
        shouldBeAutoRefreshed: function(state) {
            if(this.master === null || this.seq === 0)
                return false;

            //if(state.needsRecreation())
            //  return true;

            return (state.tm.pan_and_zoom_seq !== this.seq);
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // global chart underlay (time-frame highlighting)

    NETDATA.globalChartUnderlay = {
        callback: null,         // what to call when a highlighted range is setup
        after: null,            // highlight after this time
        before: null,           // highlight before this time
        view_after: null,       // the charts after_ms viewport when the highlight was setup
        view_before: null,      // the charts before_ms viewport, when the highlight was setup
        state: null,            // the chart the highlight was setup

        isActive: function() {
            return (this.after !== null && this.before !== null);
        },

        hasViewport: function() {
            return (this.state !== null && this.view_after !== null && this.view_before !== null);
        },

        init: function(state, after, before, view_after, view_before) {
            this.state = (typeof state !== 'undefined') ? state : null;
            this.after = (typeof after !== 'undefined' && after !== null && after > 0) ? after : null;
            this.before = (typeof before !== 'undefined' && before !== null && before > 0) ? before : null;
            this.view_after = (typeof view_after !== 'undefined' && view_after !== null && view_after > 0) ? view_after : null;
            this.view_before = (typeof view_before !== 'undefined' && view_before !== null && view_before > 0) ? view_before : null;
        },

        setup: function() {
            if(this.isActive() === true) {
                if (this.state === null)
                    this.state = NETDATA.options.targets[0];

                if (typeof this.callback === 'function')
                    this.callback(true, this.after, this.before);
            }
            else {
                if (typeof this.callback === 'function')
                    this.callback(false, 0, 0);
            }
        },

        set: function(state, after, before, view_after, view_before) {
            if(after > before) {
                var t = after;
                after = before;
                before = t;
            }

            this.init(state, after, before, view_after, view_before);

            if (this.hasViewport() === true)
                NETDATA.globalPanAndZoom.setMaster(this.state, this.view_after, this.view_before);

            this.setup();
        },

        clear: function() {
            this.after = null;
            this.before = null;
            this.state = null;
            this.view_after = null;
            this.view_before = null;

            if(typeof this.callback === 'function')
                this.callback(false, 0, 0);
        },

        focus: function() {
            if(this.isActive() === true && this.hasViewport() === true) {
                if(this.state === null)
                    this.state = NETDATA.options.targets[0];

                if(NETDATA.globalPanAndZoom.isMaster(this.state) === true)
                    NETDATA.globalPanAndZoom.clearMaster();

                NETDATA.globalPanAndZoom.setMaster(this.state, this.view_after, this.view_before, true);
            }
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // dimensions selection

    // FIXME
    // move color assignment to dimensions, here

    var dimensionStatus = function(parent, label, name_div, value_div, color) {
        this.enabled = false;
        this.parent = parent;
        this.label = label;
        this.name_div = null;
        this.value_div = null;
        this.color = NETDATA.themes.current.foreground;
        this.selected = (parent.unselected_count === 0);

        this.setOptions(name_div, value_div, color);
    };

    dimensionStatus.prototype.invalidate = function() {
        this.name_div = null;
        this.value_div = null;
        this.enabled = false;
    };

    dimensionStatus.prototype.setOptions = function(name_div, value_div, color) {
        this.color = color;

        if(this.name_div !== name_div) {
            this.name_div = name_div;
            this.name_div.title = this.label;
            this.name_div.style.setProperty('color', this.color, 'important');
            if(this.selected === false)
                this.name_div.className = 'netdata-legend-name not-selected';
            else
                this.name_div.className = 'netdata-legend-name selected';
        }

        if(this.value_div !== value_div) {
            this.value_div = value_div;
            this.value_div.title = this.label;
            this.value_div.style.setProperty('color', this.color, 'important');
            if(this.selected === false)
                this.value_div.className = 'netdata-legend-value not-selected';
            else
                this.value_div.className = 'netdata-legend-value selected';
        }

        this.enabled = true;
        this.setHandler();
    };

    dimensionStatus.prototype.setHandler = function() {
        if(this.enabled === false) return;

        var ds = this;

        // this.name_div.onmousedown = this.value_div.onmousedown = function(e) {
        this.name_div.onclick = this.value_div.onclick = function(e) {
            e.preventDefault();
            if(ds.isSelected()) {
                // this is selected
                if(e.shiftKey === true || e.ctrlKey === true) {
                    // control or shift key is pressed -> unselect this (except is none will remain selected, in which case select all)
                    ds.unselect();

                    if(ds.parent.countSelected() === 0)
                        ds.parent.selectAll();
                }
                else {
                    // no key is pressed -> select only this (except if it is the only selected already, in which case select all)
                    if(ds.parent.countSelected() === 1) {
                        ds.parent.selectAll();
                    }
                    else {
                        ds.parent.selectNone();
                        ds.select();
                    }
                }
            }
            else {
                // this is not selected
                if(e.shiftKey === true || e.ctrlKey === true) {
                    // control or shift key is pressed -> select this too
                    ds.select();
                }
                else {
                    // no key is pressed -> select only this
                    ds.parent.selectNone();
                    ds.select();
                }
            }

            ds.parent.state.redrawChart();
        }
    };

    dimensionStatus.prototype.select = function() {
        if(this.enabled === false) return;

        this.name_div.className = 'netdata-legend-name selected';
        this.value_div.className = 'netdata-legend-value selected';
        this.selected = true;
    };

    dimensionStatus.prototype.unselect = function() {
        if(this.enabled === false) return;

        this.name_div.className = 'netdata-legend-name not-selected';
        this.value_div.className = 'netdata-legend-value hidden';
        this.selected = false;
    };

    dimensionStatus.prototype.isSelected = function() {
        return(this.enabled === true && this.selected === true);
    };

    // ----------------------------------------------------------------------------------------------------------------

    var dimensionsVisibility = function(state) {
        this.state = state;
        this.len = 0;
        this.dimensions = {};
        this.selected_count = 0;
        this.unselected_count = 0;
    };

    dimensionsVisibility.prototype.dimensionAdd = function(label, name_div, value_div, color) {
        if(typeof this.dimensions[label] === 'undefined') {
            this.len++;
            this.dimensions[label] = new dimensionStatus(this, label, name_div, value_div, color);
        }
        else
            this.dimensions[label].setOptions(name_div, value_div, color);

        return this.dimensions[label];
    };

    dimensionsVisibility.prototype.dimensionGet = function(label) {
        return this.dimensions[label];
    };

    dimensionsVisibility.prototype.invalidateAll = function() {
        var keys = Object.keys(this.dimensions);
        var len = keys.length;
        while(len--)
            this.dimensions[keys[len]].invalidate();
    };

    dimensionsVisibility.prototype.selectAll = function() {
        var keys = Object.keys(this.dimensions);
        var len = keys.length;
        while(len--)
            this.dimensions[keys[len]].select();
    };

    dimensionsVisibility.prototype.countSelected = function() {
        var selected = 0;
        var keys = Object.keys(this.dimensions);
        var len = keys.length;
        while(len--)
            if(this.dimensions[keys[len]].isSelected()) selected++;

        return selected;
    };

    dimensionsVisibility.prototype.selectNone = function() {
        var keys = Object.keys(this.dimensions);
        var len = keys.length;
        while(len--)
            this.dimensions[keys[len]].unselect();
    };

    dimensionsVisibility.prototype.selected2BooleanArray = function(array) {
        var ret = [];
        this.selected_count = 0;
        this.unselected_count = 0;

        var len = array.length;
        while(len--) {
            var ds = this.dimensions[array[len]];
            if(typeof ds === 'undefined') {
                // console.log(array[i] + ' is not found');
                ret.unshift(false);
            }
            else if(ds.isSelected()) {
                ret.unshift(true);
                this.selected_count++;
            }
            else {
                ret.unshift(false);
                this.unselected_count++;
            }
        }

        if(this.selected_count === 0 && this.unselected_count !== 0) {
            this.selectAll();
            return this.selected2BooleanArray(array);
        }

        return ret;
    };


    // ----------------------------------------------------------------------------------------------------------------
    // date/time conversion

    NETDATA.dateTime = {
        using_timezone: false,

        // these are the old netdata functions
        // we fallback to these, if the new ones fail

        localeDateStringNative: function(d) {
            return d.toLocaleDateString();
        },

        localeTimeStringNative: function(d) {
            return d.toLocaleTimeString();
        },

        xAxisTimeStringNative: function(d) {
            return NETDATA.zeropad(d.getHours())  + ":"
                + NETDATA.zeropad(d.getMinutes()) + ":"
                + NETDATA.zeropad(d.getSeconds());
        },

        // initialize the new date/time conversion
        // functions.
        // if this fails, we fallback to the above
        init: function(timezone) {
            //console.log('init with timezone: ' + timezone);

            // detect browser timezone
            try {
                NETDATA.options.browser_timezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
            }
            catch(e) {
                console.log('failed to detect browser timezone: ' + e.toString());
                NETDATA.options.browser_timezone = 'cannot-detect-it';
            }

            var ret = false;

            try {
                var dateOptions ={
                    localeMatcher: 'best fit',
                    formatMatcher: 'best fit',
                    weekday: 'short',
                    year: 'numeric',
                    month: 'short',
                    day: '2-digit'
                };

                var timeOptions = {
                    localeMatcher: 'best fit',
                    hour12: false,
                    formatMatcher: 'best fit',
                    hour: '2-digit',
                    minute: '2-digit',
                    second: '2-digit'
                };

                var xAxisOptions = {
                    localeMatcher: 'best fit',
                    hour12: false,
                    formatMatcher: 'best fit',
                    hour: '2-digit',
                    minute: '2-digit',
                    second: '2-digit'
                };

                if(typeof timezone === 'string' && timezone !== '' && timezone !== 'default') {
                    dateOptions.timeZone  = timezone;
                    timeOptions.timeZone  = timezone;
                    timeOptions.timeZoneName = 'short';
                    xAxisOptions.timeZone = timezone;
                    this.using_timezone = true;
                }
                else {
                    timezone = 'default';
                    this.using_timezone = false;
                }

                this.dateFormat  = new Intl.DateTimeFormat(navigator.language, dateOptions);
                this.timeFormat  = new Intl.DateTimeFormat(navigator.language, timeOptions);
                this.xAxisFormat = new Intl.DateTimeFormat(navigator.language, xAxisOptions);

                this.localeDateString = function(d) {
                    return this.dateFormat.format(d);
                };

                this.localeTimeString = function(d) {
                    return this.timeFormat.format(d);
                };

                this.xAxisTimeString = function(d) {
                    return this.xAxisFormat.format(d);
                };

                var d = new Date();
                var t = this.dateFormat.format(d) + ' ' + this.timeFormat.format(d) + ' ' + this.xAxisFormat.format(d);

                ret = true;
            }
            catch(e) {
                console.log('Cannot setup Date/Time formatting: ' + e.toString());

                timezone = 'default';
                this.localeDateString = this.localeDateStringNative;
                this.localeTimeString = this.localeTimeStringNative;
                this.xAxisTimeString  = this.xAxisTimeStringNative;
                this.using_timezone = false;

                ret = false;
            }

            // save it
            //console.log('init setOption timezone: ' + timezone);
            NETDATA.setOption('timezone', timezone);

            return ret;
        }
    };
    NETDATA.dateTime.init(NETDATA.options.current.timezone);


    // ----------------------------------------------------------------------------------------------------------------
    // units conversion

    NETDATA.unitsConversion = {
        keys: {},       // keys for data-common-units
        latest: {},     // latest selected units for data-common-units

        globalReset: function() {
            this.keys = {};
            this.latest = {};
        },

        scalableUnits: {
            'kilobits/s': {
                'bits/s': 1 / 1000,
                'kilobits/s': 1,
                'megabits/s': 1000,
                'gigabits/s': 1000000
            },
            'kilobytes/s': {
                'bytes/s': 1 / 1024,
                'kilobytes/s': 1,
                'megabytes/s': 1024,
                'gigabytes/s': 1024 * 1024
            },
            'KB/s': {
                'B/s': 1 / 1024,
                'KB/s': 1,
                'MB/s': 1024,
                'GB/s': 1024 * 1024
            },
            'KB': {
                'B': 1 / 1024,
                'KB': 1,
                'MB': 1024,
                'GB': 1024 * 1024
            },
            'MB': {
                'KB': 1 / 1024,
                'MB': 1,
                'GB': 1024,
                'TB': 1024 * 1024
            },
            'GB': {
                'MB': 1 / 1024,
                'GB': 1,
                'TB': 1024
            }
            /*
            'seconds': {
                'milliseconds': 0.001,
                'seconds': 1,
                'minutes': 60,
                'hours': 3600,
                'days': 86400
            }
            */
        },

        convertibleUnits: {
            'Celsius': {
                'Fahrenheit': {
                    check: function() { return NETDATA.options.current.temperature === 'fahrenheit'; },
                    convert: function(value) { return value * 9 / 5 + 32; }
                }
            },
            'celsius': {
                'fahrenheit': {
                    check: function() { return NETDATA.options.current.temperature === 'fahrenheit'; },
                    convert: function(value) { return value * 9 / 5 + 32; }
                }
            },
            'seconds': {
                'time': {
                    check: function () { return NETDATA.options.current.seconds_as_time; },
                    convert: function (seconds) {
                        seconds = Math.abs(seconds);

                        var days = Math.floor(seconds / 86400);
                        seconds -= days * 86400;

                        var hours = Math.floor(seconds / 3600);
                        seconds -= hours * 3600;

                        var minutes = Math.floor(seconds / 60);
                        seconds -= minutes * 60;

                        seconds = Math.round(seconds);

                        var ms_txt = '';
                        /*
                        var ms = seconds - Math.floor(seconds);
                        seconds -= ms;
                        ms = Math.round(ms * 1000);

                        if(ms > 1) {
                            if(ms < 10)
                                ms_txt = '.00' + ms.toString();
                            else if(ms < 100)
                                ms_txt = '.0' + ms.toString();
                            else
                                ms_txt = '.' + ms.toString();
                        }
                        */

                        return ((days > 0)?days.toString() + 'd:':'').toString()
                            + NETDATA.zeropad(hours) + ':'
                            + NETDATA.zeropad(minutes) + ':'
                            + NETDATA.zeropad(seconds)
                            + ms_txt;
                    }
                }
            }
        },

        // get a function that converts the units
        // + every time units are switched call the callback
        get: function(uuid, min, max, units, desired_units, common_units_name, switch_units_callback) {
            // validate the parameters
            if(typeof units === 'undefined')
                units = 'undefined';

            // check if we support units conversion
            if(typeof this.scalableUnits[units] === 'undefined' && typeof this.convertibleUnits[units] === 'undefined') {
                // we can't convert these units
                //console.log('DEBUG: ' + uuid.toString() + ' can\'t convert units: ' + units.toString());
                return function(value) { return value; };
            }

            // check if the caller wants the original units
            if(typeof desired_units === 'undefined' || desired_units === null || desired_units === 'original' || desired_units === units) {
                //console.log('DEBUG: ' + uuid.toString() + ' original units wanted');
                switch_units_callback(units);
                return function(value) { return value; };
            }

            // now we know we can convert the units
            // and the caller wants some kind of conversion

            var tunits = null;
            var tdivider = 0;
            var x;

            if(typeof this.scalableUnits[units] !== 'undefined') {
                // units that can be scaled
                // we decide a divider

                // console.log('NETDATA.unitsConversion.get(' + units.toString() + ', ' + desired_units.toString() + ', function()) decide divider with min = ' + min.toString() + ', max = ' + max.toString());

                if (desired_units === 'auto') {
                    // the caller wants to auto-scale the units

                    // find the absolute maximum value that is rendered on the chart
                    // based on this we decide the scale
                    min = Math.abs(min);
                    max = Math.abs(max);
                    if (min > max) max = min;

                    // find the smallest scale that provides integers
                    for (x in this.scalableUnits[units]) {
                        if (this.scalableUnits[units].hasOwnProperty(x)) {
                            var m = this.scalableUnits[units][x];
                            if (m <= max && m > tdivider) {
                                tunits = x;
                                tdivider = m;
                            }
                        }
                    }

                    if(tunits === null || tdivider <= 0) {
                        // we couldn't find one
                        //console.log('DEBUG: ' + uuid.toString() + ' cannot find an auto-scaling candidate for units: ' + units.toString() + ' (max: ' + max.toString() + ')');
                        switch_units_callback(units);
                        return function(value) { return value; };
                    }

                    if(typeof common_units_name === 'string' && typeof uuid === 'string') {
                        // the caller wants several charts to have the same units
                        // data-common-units

                        var common_units_key = common_units_name + '-' + units;

                        // add our divider into the list of keys
                        var t = this.keys[common_units_key];
                        if(typeof t === 'undefined') {
                            this.keys[common_units_key] = {};
                            t = this.keys[common_units_key];
                        }
                        t[uuid] = {
                            units: tunits,
                            divider: tdivider
                        };

                        // find the max divider of all charts
                        var common_units = t[uuid];
                        for(x in t) {
                            if (t.hasOwnProperty(x) && t[x].divider > common_units.divider)
                                common_units = t[x];
                        }

                        // save our common_max to the latest keys
                        var latest = this.latest[common_units_key];
                        if(typeof latest === 'undefined') {
                            this.latest[common_units_key] = {};
                            latest = this.latest[common_units_key];
                        }
                        latest.units = common_units.units;
                        latest.divider = common_units.divider;

                        tunits = latest.units;
                        tdivider = latest.divider;

                        //console.log('DEBUG: ' + uuid.toString() + ' converted units: ' + units.toString() + ' to units: ' + tunits.toString() + ' with divider ' + tdivider.toString() + ', common-units=' + common_units_name.toString() + ((t[uuid].divider !== tdivider)?' USED COMMON, mine was ' + t[uuid].units:' set common').toString());

                        // apply it to this chart
                        switch_units_callback(tunits);
                        return function(value) {
                            if(tdivider !== latest.divider) {
                                // another chart switched our common units
                                // we should switch them too
                                //console.log('DEBUG: ' + uuid + ' switching units due to a common-units change, from ' + tunits.toString() + ' to ' + latest.units.toString());
                                tunits = latest.units;
                                tdivider = latest.divider;
                                switch_units_callback(tunits);
                            }

                            return value / tdivider;
                        }
                    }
                    else {
                        // the caller did not give data-common-units
                        // this chart auto-scales independently of all others
                        //console.log('DEBUG: ' + uuid.toString() + ' converted units: ' + units.toString() + ' to units: ' + tunits.toString() + ' with divider ' + tdivider.toString() + ', autonomously');

                        switch_units_callback(tunits);
                        return function (value) { return value / tdivider; };
                    }
                }
                else {
                    // the caller wants specific units

                    if(typeof this.scalableUnits[units][desired_units] !== 'undefined') {
                        // all good, set the new units
                        tdivider = this.scalableUnits[units][desired_units];
                        // console.log('DEBUG: ' + uuid.toString() + ' converted units: ' + units.toString() + ' to units: ' + desired_units.toString() + ' with divider ' + tdivider.toString() + ', by reference');
                        switch_units_callback(desired_units);
                        return function (value) { return value / tdivider; };
                    }
                    else {
                        // oops! switch back to original units
                        console.log('Units conversion from ' + units.toString() + ' to ' + desired_units.toString() + ' is not supported.');
                        switch_units_callback(units);
                        return function (value) { return value; };
                    }
                }
           }
           else if(typeof this.convertibleUnits[units] !== 'undefined') {
                // units that can be converted
                if(desired_units === 'auto') {
                    for(x in this.convertibleUnits[units]) {
                        if (this.convertibleUnits[units].hasOwnProperty(x)) {
                            if (this.convertibleUnits[units][x].check()) {
                                //console.log('DEBUG: ' + uuid.toString() + ' converting ' + units.toString() + ' to: ' + x.toString());
                                switch_units_callback(x);
                                return this.convertibleUnits[units][x].convert;
                            }
                        }
                    }

                    // none checked ok
                    //console.log('DEBUG: ' + uuid.toString() + ' no conversion available for ' + units.toString() + ' to: ' + desired_units.toString());
                    switch_units_callback(units);
                    return function (value) { return value; };
                }
                else if(typeof this.convertibleUnits[units][desired_units] !== 'undefined') {
                    switch_units_callback(desired_units);
                    return this.convertibleUnits[units][desired_units].convert;
                }
                else {
                    console.log('Units conversion from ' + units.toString() + ' to ' + desired_units.toString() + ' is not supported.');
                    switch_units_callback(units);
                    return function (value) { return value; };
                }
           }
           else {
                // hm... did we forget to implement the new type?
                console.log('Unmatched unit conversion method for units ' + units.toString());
                switch_units_callback(units);
                return function (value) { return value; };
           }
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // global selection sync

    NETDATA.globalSelectionSync = {
        state: null,
        dont_sync_before: 0,
        last_t: 0,
        slaves: [],
        timeout_id: undefined,

        globalReset: function() {
            this.stop();
            this.state = null;
            this.dont_sync_before =  0;
            this.last_t = 0;
            this.slaves = [];
            this.timeout_id = undefined;
        },

        active: function() {
            return (this.state !== null);
        },

        // return true if global selection sync can be enabled now
        enabled: function() {
            // console.log('enabled()');
            // can we globally apply selection sync?
            if(NETDATA.options.current.sync_selection === false)
                return false;

            return (this.dont_sync_before <= Date.now());
        },

        // set the global selection sync master
        setMaster: function(state) {
            if(this.enabled() === false) {
                this.stop();
                return;
            }

            if(this.state === state)
                return;

            if(this.state !== null)
                this.stop();

            if(NETDATA.options.debug.globalSelectionSync === true)
                console.log('globalSelectionSync.setMaster(' + state.id + ')');

            state.selected = true;
            this.state = state;
            this.last_t = 0;

            // find all slaves
            this.slaves = [];
            var len = NETDATA.options.targets.length;
            while(len--) {
                var st = NETDATA.options.targets[len];
                if (this.state !== st && st.globalSelectionSyncIsEligible() === true)
                    this.slaves.push(st);
            }

            // this.delay(100);
        },

        // stop global selection sync
        stop: function() {
            if(this.state !== null) {
                if(NETDATA.options.debug.globalSelectionSync === true)
                    console.log('globalSelectionSync.stop()');

                var len = this.slaves.length;
                while (len--)
                    this.slaves[len].clearSelection();

                this.state.clearSelection();

                this.last_t = 0;
                this.slaves = [];
                this.state = null;
            }
        },

        // delay global selection sync for some time
        delay: function(ms) {
            if(NETDATA.options.current.sync_selection === true) {
                if(NETDATA.options.debug.globalSelectionSync === true)
                    console.log('globalSelectionSync.delay()');

                if(typeof ms === 'number')
                    this.dont_sync_before = Date.now() + ms;
                else
                    this.dont_sync_before = Date.now() + NETDATA.options.current.sync_selection_delay;
            }
        },

        __syncSlaves: function() {
            if(NETDATA.globalSelectionSync.enabled() === true) {
                if(NETDATA.options.debug.globalSelectionSync === true)
                    console.log('globalSelectionSync.__syncSlaves()');

                var t = NETDATA.globalSelectionSync.last_t;
                var len = NETDATA.globalSelectionSync.slaves.length;
                while (len--)
                    NETDATA.globalSelectionSync.slaves[len].setSelection(t);

                this.timeout_id = undefined;
            }
        },

        // sync all the visible charts to the given time
        // this is to be called from the chart libraries
        sync: function(state, t) {
            if(NETDATA.options.current.sync_selection === true) {
                if(NETDATA.options.debug.globalSelectionSync === true)
                    console.log('globalSelectionSync.sync(' + state.id + ', ' + t.toString() + ')');

                this.setMaster(state);

                if(t === this.last_t)
                    return;

                this.last_t = t;

                if (this.timeout_id)
                    NETDATA.timeout.clear(this.timeout_id);

                this.timeout_id = NETDATA.timeout.set(this.__syncSlaves, 0);
            }
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Our state object, where all per-chart values are stored

    var chartState = function(element) {
        this.element = element;

        // IMPORTANT:
        // all private functions should use 'that', instead of 'this'
        var that = this;

        // ============================================================================================================
        // ERROR HANDLING

        /* error() - private
         * show an error instead of the chart
         */
        var error = function(msg) {
            var ret = true;

            if(typeof netdataErrorCallback === 'function') {
                ret = netdataErrorCallback('chart', that.id, msg);
            }

            if(ret) {
                that.element.innerHTML = that.id + ': ' + msg;
                that.enabled = false;
                that.current = that.pan;
            }
        };

        // console logging
        this.log = function(msg) {
            console.log(this.id + ' (' + this.library_name + ' ' + this.uuid + '): ' + msg);
        };


        // ============================================================================================================
        // EARLY INITIALIZATION

        // These are variables that should exist even if the chart is never to be rendered.
        // Be careful what you add here - there may be thousands of charts on the page.

        // GUID - a unique identifier for the chart
        this.uuid = NETDATA.guid();

        // string - the name of chart
        this.id = NETDATA.dataAttribute(this.element, 'netdata', undefined);
        if(typeof this.id === 'undefined') {
            error("netdata elements need data-netdata");
            return;
        }

        // string - the key for localStorage settings
        this.settings_id = NETDATA.dataAttribute(this.element, 'id', null);

        // the user given dimensions of the element
        this.width = NETDATA.dataAttribute(this.element, 'width', NETDATA.chartDefaults.width);
        this.height = NETDATA.dataAttribute(this.element, 'height', NETDATA.chartDefaults.height);
        this.height_original = this.height;

        if(this.settings_id !== null) {
            this.height = NETDATA.localStorageGet('chart_heights.' + this.settings_id, this.height, function(height) {
                // this is the callback that will be called
                // if and when the user resets all localStorage variables
                // to their defaults

                resizeChartToHeight(height);
            });
        }

        // the chart library requested by the user
        this.library_name = NETDATA.dataAttribute(this.element, 'chart-library', NETDATA.chartDefaults.library);

        // check the requested library is available
        // we don't initialize it here - it will be initialized when
        // this chart will be first used
        if(typeof NETDATA.chartLibraries[this.library_name] === 'undefined') {
            NETDATA.error(402, this.library_name);
            error('chart library "' + this.library_name + '" is not found');
            this.enabled = false;
        }
        else if(NETDATA.chartLibraries[this.library_name].enabled === false) {
            NETDATA.error(403, this.library_name);
            error('chart library "' + this.library_name + '" is not enabled');
            this.enabled = false;
        }
        else
            this.library = NETDATA.chartLibraries[this.library_name];

        this.auto = {
            name: 'auto',
            autorefresh: true,
            force_update_at: 0, // the timestamp to force the update at
            force_before_ms: null,
            force_after_ms: null
        };
        this.pan = {
            name: 'pan',
            autorefresh: false,
            force_update_at: 0, // the timestamp to force the update at
            force_before_ms: null,
            force_after_ms: null
        };
        this.zoom = {
            name: 'zoom',
            autorefresh: false,
            force_update_at: 0, // the timestamp to force the update at
            force_before_ms: null,
            force_after_ms: null
        };

        // this is a pointer to one of the sub-classes below
        // auto, pan, zoom
        this.current = this.auto;

        this.running = false;                       // boolean - true when the chart is being refreshed now
        this.enabled = true;                        // boolean - is the chart enabled for refresh?

        that.tmp = {};

        // ============================================================================================================
        // PRIVATE FUNCTIONS

        // reset the runtime status variables to their defaults
        var runtimeInit = function() {
            that.paused = false;                        // boolean - is the chart paused for any reason?
            that.selected = false;                      // boolean - is the chart shown a selection?

            that.chart_created = false;                 // boolean - is the library.create() been called?
            that.dom_created = false;                   // boolean - is the chart DOM been created?
            that.fetching_data = false;                 // boolean - true while we fetch data via ajax

            that.updates_counter = 0;                   // numeric - the number of refreshes made so far
            that.updates_since_last_unhide = 0;         // numeric - the number of refreshes made since the last time the chart was unhidden
            that.updates_since_last_creation = 0;       // numeric - the number of refreshes made since the last time the chart was created

            that.tm = {
                last_initialized: 0,                    // milliseconds - the timestamp it was last initialized
                last_dom_created: 0,                    // milliseconds - the timestamp its DOM was last created
                last_mode_switch: 0,                    // milliseconds - the timestamp it switched modes

                last_info_downloaded: 0,                // milliseconds - the timestamp we downloaded the chart
                last_updated: 0,                        // the timestamp the chart last updated with data
                pan_and_zoom_seq: 0,                    // the sequence number of the global synchronization
                                                        // between chart.
                                                        // Used with NETDATA.globalPanAndZoom.seq
                last_visible_check: 0,                  // the time we last checked if it is visible
                last_resized: 0,                        // the time the chart was resized
                last_hidden: 0,                         // the time the chart was hidden
                last_unhidden: 0,                       // the time the chart was unhidden
                last_autorefreshed: 0                   // the time the chart was last refreshed
            };

            that.data = null;                           // the last data as downloaded from the netdata server
            that.data_url = 'invalid://';               // string - the last url used to update the chart
            that.data_points = 0;                       // number - the number of points returned from netdata
            that.data_after = 0;                        // milliseconds - the first timestamp of the data
            that.data_before = 0;                       // milliseconds - the last timestamp of the data
            that.data_update_every = 0;                 // milliseconds - the frequency to update the data

            that.tmp = {};                              // members that can be destroyed to save memory
        };

        // initialize all the variables that are required for the chart to be rendered
        var lateInitialization = function() {
            if(typeof that.host !== 'undefined')
                return;

            // string - the netdata server URL, without any path
            that.host = NETDATA.dataAttribute(that.element, 'host', NETDATA.serverDefault);

            // make sure the host does not end with /
            // all netdata API requests use absolute paths
            while(that.host.slice(-1) === '/')
                that.host = that.host.substring(0, that.host.length - 1);

            // string - the grouping method requested by the user
            that.method = NETDATA.dataAttribute(that.element, 'method', NETDATA.chartDefaults.method);

            // the time-range requested by the user
            that.after = NETDATA.dataAttribute(that.element, 'after', NETDATA.chartDefaults.after);
            that.before = NETDATA.dataAttribute(that.element, 'before', NETDATA.chartDefaults.before);

            // the pixels per point requested by the user
            that.pixels_per_point = NETDATA.dataAttribute(that.element, 'pixels-per-point', 1);
            that.points = NETDATA.dataAttribute(that.element, 'points', null);

            // the dimensions requested by the user
            that.dimensions = NETDATA.dataAttribute(that.element, 'dimensions', null);

            that.title = NETDATA.dataAttribute(that.element, 'title', null);    // the title of the chart
            that.units = NETDATA.dataAttribute(that.element, 'units', null);    // the units of the chart dimensions
            that.units_desired = NETDATA.dataAttribute(that.element, 'desired-units', NETDATA.options.current.units); // the units of the chart dimensions
            that.units_current = that.units;
            that.units_common = NETDATA.dataAttribute(that.element, 'common-units', null);

            that.append_options = NETDATA.dataAttribute(that.element, 'append-options', null); // additional options to pass to netdata
            that.override_options = NETDATA.dataAttribute(that.element, 'override-options', null);  // override options to pass to netdata

            that.debug = NETDATA.dataAttributeBoolean(that.element, 'debug', false);

            that.value_decimal_detail = -1;
            var d = NETDATA.dataAttribute(that.element, 'decimal-digits', -1);
            if(typeof d === 'number')
                that.value_decimal_detail = d;
            else if(typeof d !== 'undefined')
                that.log('ignoring decimal-digits value: ' + d.toString());

            // if we need to report the rendering speed
            // find the element that needs to be updated
            var refresh_dt_element_name = NETDATA.dataAttribute(that.element, 'dt-element-name', null); // string - the element to print refresh_dt_ms

            if(refresh_dt_element_name !== null) {
                that.refresh_dt_element = document.getElementById(refresh_dt_element_name) || null;
            }
            else
                that.refresh_dt_element = null;

            that.dimensions_visibility = new dimensionsVisibility(that);

            that.netdata_first = 0;                     // milliseconds - the first timestamp in netdata
            that.netdata_last = 0;                      // milliseconds - the last timestamp in netdata
            that.requested_after = null;                // milliseconds - the timestamp of the request after param
            that.requested_before = null;               // milliseconds - the timestamp of the request before param
            that.requested_padding = null;
            that.view_after = 0;
            that.view_before = 0;

            that.refresh_dt_ms = 0;                     // milliseconds - the time the last refresh took

            // how many retries we have made to load chart data from the server
            that.retries_on_data_failures = 0;

            // color management
            that.colors = null;
            that.colors_assigned = {};
            that.colors_available = null;
            that.colors_custom = null;

            that.element_message = null; // the element already created by the user
            that.element_chart = null; // the element with the chart
            that.element_legend = null; // the element with the legend of the chart (if created by us)
            that.element_legend_childs = {
                content: null,
                hidden: null,
                title_date: null,
                title_time: null,
                title_units: null,
                perfect_scroller: null, // the container to apply perfect scroller to
                series: null
            };

            that.chart_url = null;                      // string - the url to download chart info
            that.chart = null;                          // object - the chart as downloaded from the server
        };

        var destroyDOM = function() {
            if(that.enabled === false) return;

            if(that.debug === true)
                that.log('destroyDOM()');

            // that.element.className = 'netdata-message icon';
            // that.element.innerHTML = '<i class="fas fa-sync"></i> netdata';
            that.element.innerHTML = '';
            that.element_message = null;
            that.element_legend = null;
            that.element_chart = null;
            that.element_legend_childs.series = null;

            that.chart_created = false;
            that.dom_created = false;

            that.tm.last_resized = 0;
            that.tm.last_dom_created = 0;
        };

        var createDOM = function() {
            if(that.enabled === false) return;
            lateInitialization();

            destroyDOM();

            if(that.debug === true)
                that.log('createDOM()');

            that.element_message = document.createElement('div');
            that.element_message.className = 'netdata-message icon hidden';
            that.element.appendChild(that.element_message);

            that.dom_created = true;
            that.chart_created = false;

            that.tm.last_dom_created =
                that.tm.last_resized = Date.now();

            showLoading();
        };

        var initDOM = function() {
            that.element.className = that.library.container_class(that);

            if(typeof(that.width) === 'string')
                that.element.style.width = that.width;
            else if(typeof(that.width) === 'number')
                that.element.style.width = that.width.toString() + 'px';

            if(typeof(that.library.aspect_ratio) === 'undefined') {
                if(typeof(that.height) === 'string')
                    that.element.style.height = that.height;
                else if(typeof(that.height) === 'number')
                    that.element.style.height = that.height.toString() + 'px';
            }

            if(NETDATA.chartDefaults.min_width !== null)
                that.element.style.min_width = NETDATA.chartDefaults.min_width;
        };

        var invisibleSearchableText = function() {
            return '<span style="position:absolute; opacity: 0; width: 0px;">' + that.id + '</span>';
        }

        /* init() private
         * initialize state variables
         * destroy all (possibly) created state elements
         * create the basic DOM for a chart
         */
        var init = function(opt) {
            if(that.enabled === false) return;

            runtimeInit();
            that.element.innerHTML = invisibleSearchableText();

            that.tm.last_initialized = Date.now();
            that.setMode('auto');

            if(opt !== 'fast') {
                if (that.isVisible(true) || opt === 'force')
                    createDOM();
            }
        };

        var maxMessageFontSize = function() {
            var screenHeight = screen.height;
            var el = that.element;

            // normally we want a font size, as tall as the element
            var h = el.clientHeight;

            // but give it some air, 20% let's say, or 5 pixels min
            var lost = Math.max(h * 0.2, 5);
            h -= lost;

            // center the text, vertically
            var paddingTop = (lost - 5) / 2;

            // but check the width too
            // it should fit 10 characters in it
            var w = el.clientWidth / 10;
            if(h > w) {
                paddingTop += (h - w) / 2;
                h = w;
            }

            // and don't make it too huge
            // 5% of the screen size is good
            if(h > screenHeight / 20) {
                paddingTop += (h - (screenHeight / 20)) / 2;
                h = screenHeight / 20;
            }

            // set it
            that.element_message.style.fontSize = h.toString() + 'px';
            that.element_message.style.paddingTop = paddingTop.toString() + 'px';
        };

        var showMessageIcon = function(icon) {
            that.element_message.innerHTML = icon;
            maxMessageFontSize();
            $(that.element_message).removeClass('hidden');
            that.tmp.___messageHidden___ = undefined;
        };

        var hideMessage = function() {
            if(typeof that.tmp.___messageHidden___ === 'undefined') {
                that.tmp.___messageHidden___ = true;
                $(that.element_message).addClass('hidden');
            }
        };

        var showRendering = function() {
            var icon;
            if(that.chart !== null) {
                if(that.chart.chart_type === 'line')
                    icon = '<i class="fas fa-chart-line"></i>';
                else
                    icon = '<i class="fas fa-chart-area"></i>';
            }
            else
                icon = '<i class="fas fa-chart-area"></i>';

            showMessageIcon(icon + ' netdata' + invisibleSearchableText());
        };

        var showLoading = function() {
            if(that.chart_created === false) {
                showMessageIcon('<i class="fas fa-sync-alt"></i> netdata');
                return true;
            }
            return false;
        };

        var isHidden = function() {
            return (typeof that.tmp.___chartIsHidden___ !== 'undefined');
        };

        // hide the chart, when it is not visible - called from isVisible()
        var hideChart = function() {
            // hide it, if it is not already hidden
            if(isHidden() === true) return;

            if(that.chart_created === true) {
                if(NETDATA.options.current.show_help === true) {
                    if(that.element_legend_childs.toolbox !== null) {
                        $(that.element_legend_childs.toolbox_left).popover('hide');
                        $(that.element_legend_childs.toolbox_reset).popover('hide');
                        $(that.element_legend_childs.toolbox_right).popover('hide');
                        $(that.element_legend_childs.toolbox_zoomin).popover('hide');
                        $(that.element_legend_childs.toolbox_zoomout).popover('hide');
                    }

                    if(that.element_legend_childs.resize_handler !== null)
                        $(that.element_legend_childs.resize_handler).popover('hide');

                    if(that.element_legend_childs.content !== null)
                        $(that.element_legend_childs.content).popover('hide');
                }

                if(NETDATA.options.current.destroy_on_hide === true) {
                    // that.log('hideChart() init');

                    // we should destroy it
                    init('force');
                }
                else {
                    // that.log('hideChart()');

                    showRendering();
                    that.element_chart.style.display = 'none';
                    that.element.style.willChange = 'auto';
                    if(that.element_legend !== null) that.element_legend.style.display = 'none';
                    if(that.element_legend_childs.toolbox !== null) that.element_legend_childs.toolbox.style.display = 'none';
                    if(that.element_legend_childs.resize_handler !== null) that.element_legend_childs.resize_handler.style.display = 'none';

                    that.tm.last_hidden = Date.now();

                    // de-allocate data
                    // This works, but I not sure there are no corner cases somewhere
                    // so it is commented - if the user has memory issues he can
                    // set Destroy on Hide for all charts
                    // that.data = null;
                }
            }

            that.tmp.___chartIsHidden___ = true;
        };

        // unhide the chart, when it is visible - called from isVisible()
        var unhideChart = function() {
            if(isHidden() === false) return;

            that.tmp.___chartIsHidden___ = undefined;
            that.updates_since_last_unhide = 0;

            if(that.chart_created === false) {
                // that.log('unhideChart() init');
                // we need to re-initialize it, to show our background
                // logo in bootstrap tabs, until the chart loads
                init('force');
            }
            else {
                // that.log('unhideChart()');
                that.element.style.willChange = 'transform';
                that.tm.last_unhidden = Date.now();
                that.element_chart.style.display = '';
                if(that.element_legend !== null) that.element_legend.style.display = '';
                if(that.element_legend_childs.toolbox !== null) that.element_legend_childs.toolbox.style.display = '';
                if(that.element_legend_childs.resize_handler !== null) that.element_legend_childs.resize_handler.style.display = '';
                resizeChart();
                hideMessage();
            }
        };

        var canBeRendered = function(uncached_visibility) {
            return (
                (
                    NETDATA.options.page_is_visible === true ||
                    NETDATA.options.current.stop_updates_when_focus_is_lost === false ||
                    that.updates_since_last_unhide === 0
                )
                && isHidden() === false && that.isVisible(uncached_visibility) === true
            );
        };

        // https://github.com/petkaantonov/bluebird/wiki/Optimization-killers
        var callChartLibraryUpdateSafely = function(data) {
            var status;

            // we should not do this here
            // if we prevent rendering the chart then:
            // 1. globalSelectionSync will be wrong
            // 2. globalPanAndZoom will be wrong
            //if(canBeRendered(true) === false)
            //    return false;

            if(NETDATA.options.fake_chart_rendering === true)
                return true;

            that.updates_counter++;
            that.updates_since_last_unhide++;
            that.updates_since_last_creation++;

            if(NETDATA.options.debug.chart_errors === true)
                status = that.library.update(that, data);
            else {
                try {
                    status = that.library.update(that, data);
                }
                catch(err) {
                    status = false;
                }
            }

            if(status === false) {
                error('chart failed to be updated as ' + that.library_name);
                return false;
            }

            return true;
        };

        // https://github.com/petkaantonov/bluebird/wiki/Optimization-killers
        var callChartLibraryCreateSafely = function(data) {
            var status;

            // we should not do this here
            // if we prevent rendering the chart then:
            // 1. globalSelectionSync will be wrong
            // 2. globalPanAndZoom will be wrong
            //if(canBeRendered(true) === false)
            //    return false;

            if(NETDATA.options.fake_chart_rendering === true)
                return true;

            that.updates_counter++;
            that.updates_since_last_unhide++;
            that.updates_since_last_creation++;

            if(NETDATA.options.debug.chart_errors === true)
                status = that.library.create(that, data);
            else {
                try {
                    status = that.library.create(that, data);
                }
                catch(err) {
                    status = false;
                }
            }

            if(status === false) {
                error('chart failed to be created as ' + that.library_name);
                return false;
            }

            that.chart_created = true;
            that.updates_since_last_creation = 0;
            return true;
        };

        // ----------------------------------------------------------------------------------------------------------------
        // Chart Resize

        // resizeChart() - private
        // to be called just before the chart library to make sure that
        // a properly sized dom is available
        var resizeChart = function() {
            if(that.isVisible() === true && that.tm.last_resized < NETDATA.options.last_page_resize) {
                if(that.chart_created === false) return;

                if(that.needsRecreation()) {
                    init('force');
                }
                else if(typeof that.library.resize === 'function') {
                    that.library.resize(that);

                    if(that.element_legend_childs.perfect_scroller !== null)
                        Ps.update(that.element_legend_childs.perfect_scroller);

                    maxMessageFontSize();
                }

                that.tm.last_resized = Date.now();
            }
        };

        // this is the actual chart resize algorithm
        // it will:
        // - resize the entire container
        // - update the internal states
        // - resize the chart as the div changes height
        // - update the scrollbar of the legend
        var resizeChartToHeight = function(h) {
            // console.log(h);
            that.element.style.height = h;

            if(that.settings_id !== null)
                NETDATA.localStorageSet('chart_heights.' + that.settings_id, h);

            var now = Date.now();
            NETDATA.options.last_page_scroll = now;
            NETDATA.options.auto_refresher_stop_until = now + NETDATA.options.current.stop_updates_while_resizing;

            // force a resize
            that.tm.last_resized = 0;
            resizeChart();
        };

        this.resizeForPrint = function() {
            if(typeof this.element_legend_childs !== 'undefined' && this.element_legend_childs.perfect_scroller !== null) {
                var current = this.element.clientHeight;
                var optimal = current
                    + this.element_legend_childs.perfect_scroller.scrollHeight
                    - this.element_legend_childs.perfect_scroller.clientHeight;

                if(optimal > current) {
                    // this.log('resized');
                    this.element.style.height = optimal + 'px';
                    this.library.resize(this);
                }
            }
        };

        this.resizeHandler = function(e) {
            e.preventDefault();

            if(typeof this.event_resize === 'undefined'
                || this.event_resize.chart_original_w === 'undefined'
                || this.event_resize.chart_original_h === 'undefined')
                this.event_resize = {
                    chart_original_w: this.element.clientWidth,
                    chart_original_h: this.element.clientHeight,
                    last: 0
                };

            if(e.type === 'touchstart') {
                this.event_resize.mouse_start_x = e.touches.item(0).pageX;
                this.event_resize.mouse_start_y = e.touches.item(0).pageY;
            }
            else {
                this.event_resize.mouse_start_x = e.clientX;
                this.event_resize.mouse_start_y = e.clientY;
            }

            this.event_resize.chart_start_w = this.element.clientWidth;
            this.event_resize.chart_start_h = this.element.clientHeight;
            this.event_resize.chart_last_w = this.element.clientWidth;
            this.event_resize.chart_last_h = this.element.clientHeight;

            var now = Date.now();
            if(now - this.event_resize.last <= NETDATA.options.current.double_click_speed && this.element_legend_childs.perfect_scroller !== null) {
                // double click / double tap event

                // console.dir(this.element_legend_childs.content);
                // console.dir(this.element_legend_childs.perfect_scroller);

                // the optimal height of the chart
                // showing the entire legend
                var optimal = this.event_resize.chart_last_h
                        + this.element_legend_childs.perfect_scroller.scrollHeight
                        - this.element_legend_childs.perfect_scroller.clientHeight;

                // if we are not optimal, be optimal
                if(this.event_resize.chart_last_h !== optimal) {
                    // this.log('resize to optimal, current = ' + this.event_resize.chart_last_h.toString() + 'px, original = ' + this.event_resize.chart_original_h.toString() + 'px, optimal = ' + optimal.toString() + 'px, internal = ' + this.height_original.toString());
                    resizeChartToHeight(optimal.toString() + 'px');
                }

                // else if the current height is not the original/saved height
                // reset to the original/saved height
                else if(this.event_resize.chart_last_h !== this.event_resize.chart_original_h) {
                    // this.log('resize to original, current = ' + this.event_resize.chart_last_h.toString() + 'px, original = ' + this.event_resize.chart_original_h.toString() + 'px, optimal = ' + optimal.toString() + 'px, internal = ' + this.height_original.toString());
                    resizeChartToHeight(this.event_resize.chart_original_h.toString() + 'px');
                }

                // else if the current height is not the internal default height
                // reset to the internal default height
                else if((this.event_resize.chart_last_h.toString() + 'px') !== this.height_original) {
                    // this.log('resize to internal default, current = ' + this.event_resize.chart_last_h.toString() + 'px, original = ' + this.event_resize.chart_original_h.toString() + 'px, optimal = ' + optimal.toString() + 'px, internal = ' + this.height_original.toString());
                    resizeChartToHeight(this.height_original.toString());
                }

                // else if the current height is not the firstchild's clientheight
                // resize to it
                else if(typeof this.element_legend_childs.perfect_scroller.firstChild !== 'undefined') {
                    var parent_rect = this.element.getBoundingClientRect();
                    var content_rect = this.element_legend_childs.perfect_scroller.firstElementChild.getBoundingClientRect();
                    var wanted = content_rect.top - parent_rect.top + this.element_legend_childs.perfect_scroller.firstChild.clientHeight + 18; // 15 = toolbox + 3 space

                    // console.log(parent_rect);
                    // console.log(content_rect);
                    // console.log(wanted);

                    // this.log('resize to firstChild, current = ' + this.event_resize.chart_last_h.toString() + 'px, original = ' + this.event_resize.chart_original_h.toString() + 'px, optimal = ' + optimal.toString() + 'px, internal = ' + this.height_original.toString() + 'px, firstChild = ' + wanted.toString() + 'px' );
                    if(this.event_resize.chart_last_h !== wanted)
                        resizeChartToHeight(wanted.toString() + 'px');
                }
            }
            else {
                this.event_resize.last = now;

                // process movement event
                document.onmousemove =
                document.ontouchmove =
                this.element_legend_childs.resize_handler.onmousemove =
                this.element_legend_childs.resize_handler.ontouchmove =
                    function(e) {
                        var y = null;

                        switch(e.type) {
                            case 'mousemove': y = e.clientY; break;
                            case 'touchmove': y = e.touches.item(e.touches - 1).pageY; break;
                        }

                        if(y !== null) {
                            var newH = that.event_resize.chart_start_h + y - that.event_resize.mouse_start_y;

                            if(newH >= 70 && newH !== that.event_resize.chart_last_h) {
                                resizeChartToHeight(newH.toString() + 'px');
                                that.event_resize.chart_last_h = newH;
                            }
                        }
                    };

                // process end event
                document.onmouseup =
                document.ontouchend =
                this.element_legend_childs.resize_handler.onmouseup =
                this.element_legend_childs.resize_handler.ontouchend =
                    function(e) {
                        void(e);

                        // remove all the hooks
                        document.onmouseup =
                        document.onmousemove =
                        document.ontouchmove =
                        document.ontouchend =
                        that.element_legend_childs.resize_handler.onmousemove =
                        that.element_legend_childs.resize_handler.ontouchmove =
                        that.element_legend_childs.resize_handler.onmouseout =
                        that.element_legend_childs.resize_handler.onmouseup =
                        that.element_legend_childs.resize_handler.ontouchend =
                            null;

                        // allow auto-refreshes
                        NETDATA.options.auto_refresher_stop_until = 0;
                    };
            }
        };


        var noDataToShow = function() {
            showMessageIcon('<i class="fas fa-exclamation-triangle"></i> empty');
            that.legendUpdateDOM();
            that.tm.last_autorefreshed = Date.now();
            // that.data_update_every = 30 * 1000;
            //that.element_chart.style.display = 'none';
            //if(that.element_legend !== null) that.element_legend.style.display = 'none';
            //that.tmp.___chartIsHidden___ = true;
        };

        // ============================================================================================================
        // PUBLIC FUNCTIONS

        this.error = function(msg) {
            error(msg);
        };

        this.setMode = function(m) {
            if(this.current !== null && this.current.name === m) return;

            if(m === 'auto')
                this.current = this.auto;
            else if(m === 'pan')
                this.current = this.pan;
            else if(m === 'zoom')
                this.current = this.zoom;
            else
                this.current = this.auto;

            this.current.force_update_at = 0;
            this.current.force_before_ms = null;
            this.current.force_after_ms = null;

            this.tm.last_mode_switch = Date.now();
        };

        // ----------------------------------------------------------------------------------------------------------------
        // global selection sync

        // can the chart participate to the global selection sync as a slave?
        this.globalSelectionSyncIsEligible = function() {
            return (this.enabled === true
                && this.library !== null
                && typeof this.library.setSelection === 'function'
                && this.isVisible() === true
                && this.chart_created === true);
        };

        this.setSelection = function(t) {
            if(typeof this.library.setSelection === 'function')
                this.selected = (this.library.setSelection(this, t) === true);
            else
                this.selected = true;

            if(this.selected === true && this.debug === true)
                this.log('selection set to ' + t.toString());

            return this.selected;
        };

        this.clearSelection = function() {
            if(this.selected === true) {
                if(typeof this.library.clearSelection === 'function')
                    this.selected = (this.library.clearSelection(this) !== true);
                else
                    this.selected = false;

                if(this.selected === false && this.debug === true)
                    this.log('selection cleared');

                this.legendReset();
            }

            return this.selected;
        };

        // ----------------------------------------------------------------------------------------------------------------

        // find if a timestamp (ms) is shown in the current chart
        this.timeIsVisible = function(t) {
            return (t >= this.data_after && t <= this.data_before);
        };

        this.calculateRowForTime = function(t) {
            if(this.timeIsVisible(t) === false) return -1;
            return Math.floor((t - this.data_after) / this.data_update_every);
        };

        // ----------------------------------------------------------------------------------------------------------------

        this.pauseChart = function() {
            if(this.paused === false) {
                if(this.debug === true)
                    this.log('pauseChart()');

                this.paused = true;
            }
        };

        this.unpauseChart = function() {
            if(this.paused === true) {
                if(this.debug === true)
                    this.log('unpauseChart()');

                this.paused = false;
            }
        };

        this.resetChart = function(dont_clear_master, dont_update) {
            if(this.debug === true)
                this.log('resetChart(' + dont_clear_master + ', ' + dont_update + ') called');

            if(typeof dont_clear_master === 'undefined')
                dont_clear_master = false;

            if(typeof dont_update === 'undefined')
                dont_update = false;

            if(dont_clear_master !== true && NETDATA.globalPanAndZoom.isMaster(this) === true) {
                if(this.debug === true)
                    this.log('resetChart() diverting to clearMaster().');
                // this will call us back with master === true
                NETDATA.globalPanAndZoom.clearMaster();
                return;
            }

            this.clearSelection();

            this.tm.pan_and_zoom_seq = 0;

            this.setMode('auto');
            this.current.force_update_at = 0;
            this.current.force_before_ms = null;
            this.current.force_after_ms = null;
            this.tm.last_autorefreshed = 0;
            this.paused = false;
            this.selected = false;
            this.enabled = true;
            // this.debug = false;

            // do not update the chart here
            // or the chart will flip-flop when it is the master
            // of a selection sync and another chart becomes
            // the new master

            if(dont_update !== true && this.isVisible() === true) {
                this.updateChart();
            }
        };

        this.updateChartPanOrZoom = function(after, before, callback) {
            var logme = 'updateChartPanOrZoom(' + after + ', ' + before + '): ';
            var ret = true;

            NETDATA.globalPanAndZoom.delay();
            NETDATA.globalSelectionSync.delay();

            if(this.debug === true)
                this.log(logme);

            if(before < after) {
                if(this.debug === true)
                    this.log(logme + 'flipped parameters, rejecting it.');

                return false;
            }

            if(typeof this.fixed_min_duration === 'undefined')
                this.fixed_min_duration = Math.round((this.chartWidth() / 30) * this.chart.update_every * 1000);

            var min_duration = this.fixed_min_duration;
            var current_duration = Math.round(this.view_before - this.view_after);

            // round the numbers
            after = Math.round(after);
            before = Math.round(before);

            // align them to update_every
            // stretching them further away
            after -= after % this.data_update_every;
            before += this.data_update_every - (before % this.data_update_every);

            // the final wanted duration
            var wanted_duration = before - after;

            // to allow panning, accept just a point below our minimum
            if((current_duration - this.data_update_every) < min_duration)
                min_duration = current_duration - this.data_update_every;

            // we do it, but we adjust to minimum size and return false
            // when the wanted size is below the current and the minimum
            // and we zoom
            if(wanted_duration < current_duration && wanted_duration < min_duration) {
                if(this.debug === true)
                    this.log(logme + 'too small: min_duration: ' + (min_duration / 1000).toString() + ', wanted: ' + (wanted_duration / 1000).toString());

                min_duration = this.fixed_min_duration;

                var dt = (min_duration - wanted_duration) / 2;
                before += dt;
                after -= dt;
                wanted_duration = before - after;
                ret = false;
            }

            var tolerance = this.data_update_every * 2;
            var movement = Math.abs(before - this.view_before);

            if(Math.abs(current_duration - wanted_duration) <= tolerance && movement <= tolerance && ret === true) {
                if(this.debug === true)
                    this.log(logme + 'REJECTING UPDATE: current/min duration: ' + (current_duration / 1000).toString() + '/' + (this.fixed_min_duration / 1000).toString() + ', wanted duration: ' + (wanted_duration / 1000).toString() + ', duration diff: ' + (Math.round(Math.abs(current_duration - wanted_duration) / 1000)).toString() + ', movement: ' + (movement / 1000).toString() + ', tolerance: ' + (tolerance / 1000).toString() + ', returning: ' + false);
                return false;
            }

            if(this.current.name === 'auto') {
                this.log(logme + 'caller called me with mode: ' + this.current.name);
                this.setMode('pan');
            }

            if(this.debug === true)
                this.log(logme + 'ACCEPTING UPDATE: current/min duration: ' + (current_duration / 1000).toString() + '/' + (this.fixed_min_duration / 1000).toString() + ', wanted duration: ' + (wanted_duration / 1000).toString() + ', duration diff: ' + (Math.round(Math.abs(current_duration - wanted_duration) / 1000)).toString() + ', movement: ' + (movement / 1000).toString() + ', tolerance: ' + (tolerance / 1000).toString() + ', returning: ' + ret);

            this.current.force_update_at = Date.now() + NETDATA.options.current.pan_and_zoom_delay;
            this.current.force_after_ms = after;
            this.current.force_before_ms = before;
            NETDATA.globalPanAndZoom.setMaster(this, after, before);

            if(ret === true && typeof callback === 'function')
                callback();

            return ret;
        };

        this.updateChartPanOrZoomAsyncTimeOutId = undefined;
        this.updateChartPanOrZoomAsync = function(after, before, callback) {
            NETDATA.globalPanAndZoom.delay();
            NETDATA.globalSelectionSync.delay();

            if(NETDATA.globalPanAndZoom.isMaster(this) === false) {
                this.pauseChart();
                NETDATA.globalPanAndZoom.setMaster(this, after, before);
                // NETDATA.globalSelectionSync.stop();
                NETDATA.globalSelectionSync.setMaster(this);
            }

            if(this.updateChartPanOrZoomAsyncTimeOutId)
                NETDATA.timeout.clear(this.updateChartPanOrZoomAsyncTimeOutId);

            NETDATA.timeout.set(function() {
                that.updateChartPanOrZoomAsyncTimeOutId = undefined;
                that.updateChartPanOrZoom(after, before, callback);
            }, 0);
        };

        var __unitsConversionLastUnits = undefined;
        var __unitsConversionLastUnitsDesired = undefined;
        var __unitsConversionLastMin = undefined;
        var __unitsConversionLastMax = undefined;
        var __unitsConversion = function(value) { return value; };
        this.unitsConversionSetup = function(min, max) {
            if(this.units !== __unitsConversionLastUnits
                || this.units_desired !== __unitsConversionLastUnitsDesired
                || min !== __unitsConversionLastMin
                || max !== __unitsConversionLastMax) {

                __unitsConversionLastUnits = this.units;
                __unitsConversionLastUnitsDesired = this.units_desired;
                __unitsConversionLastMin = min;
                __unitsConversionLastMax = max;

                __unitsConversion = NETDATA.unitsConversion.get(this.uuid, min, max, this.units, this.units_desired, this.units_common, function (units) {
                    // console.log('switching units from ' + that.units.toString() + ' to ' + units.toString());
                    that.units_current = units;
                    that.legendSetUnitsString(that.units_current);
                });
            }
        };

        var __legendFormatValueChartDecimalsLastMin = undefined;
        var __legendFormatValueChartDecimalsLastMax = undefined;
        var __legendFormatValueChartDecimals = -1;
        var __intlNumberFormat = null;
        this.legendFormatValueDecimalsFromMinMax = function(min, max) {
            if(min === __legendFormatValueChartDecimalsLastMin && max === __legendFormatValueChartDecimalsLastMax)
                return;

            this.unitsConversionSetup(min, max);
            if(__unitsConversion !== null) {
                min = __unitsConversion(min);
                max = __unitsConversion(max);

                if(typeof min !== 'number' || typeof max !== 'number')
                    return;
            }

            __legendFormatValueChartDecimalsLastMin = min;
            __legendFormatValueChartDecimalsLastMax = max;

            var old = __legendFormatValueChartDecimals;

            if(this.data !== null && this.data.min === this.data.max)
                // it is a fixed number, let the visualizer decide based on the value
                __legendFormatValueChartDecimals = -1;

            else if(this.value_decimal_detail !== -1)
                // there is an override
                __legendFormatValueChartDecimals = this.value_decimal_detail;

            else {
                // ok, let's calculate the proper number of decimal points
                var delta;

                if (min === max)
                    delta = Math.abs(min);
                else
                    delta = Math.abs(max - min);

                if (delta > 1000)        __legendFormatValueChartDecimals = 0;
                else if (delta > 10)     __legendFormatValueChartDecimals = 1;
                else if (delta > 1)      __legendFormatValueChartDecimals = 2;
                else if (delta > 0.1)    __legendFormatValueChartDecimals = 2;
                else if (delta > 0.01)   __legendFormatValueChartDecimals = 4;
                else if (delta > 0.001)  __legendFormatValueChartDecimals = 5;
                else if (delta > 0.0001) __legendFormatValueChartDecimals = 6;
                else                     __legendFormatValueChartDecimals = 7;
            }

            if(__legendFormatValueChartDecimals !== old) {
                if(__legendFormatValueChartDecimals < 0)
                    __intlNumberFormat = null;
                else
                    __intlNumberFormat = NETDATA.fastNumberFormat.get(
                        __legendFormatValueChartDecimals,
                        __legendFormatValueChartDecimals
                    );
            }
        };

        this.legendFormatValue = function(value) {
            if(typeof value !== 'number')
                return '-';

            value = __unitsConversion(value);

            if(typeof value !== 'number')
                return value;

            if(__intlNumberFormat !== null)
                return __intlNumberFormat.format(value);

            var dmin, dmax;
            if(this.value_decimal_detail !== -1) {
                dmin = dmax = this.value_decimal_detail;
            }
            else {
                dmin = 0;
                var abs = (value < 0) ? -value : value;
                if (abs > 1000)        dmax = 0;
                else if (abs > 10)     dmax = 1;
                else if (abs > 1)      dmax = 2;
                else if (abs > 0.1)    dmax = 2;
                else if (abs > 0.01)   dmax = 4;
                else if (abs > 0.001)  dmax = 5;
                else if (abs > 0.0001) dmax = 6;
                else                   dmax = 7;
            }

            return NETDATA.fastNumberFormat.get(dmin, dmax).format(value);
        };

        this.legendSetLabelValue = function(label, value) {
            var series = this.element_legend_childs.series[label];
            if(typeof series === 'undefined') return;
            if(series.value === null && series.user === null) return;

            /*
            // this slows down firefox and edge significantly
            // since it requires to use innerHTML(), instead of innerText()

            // if the value has not changed, skip DOM update
            //if(series.last === value) return;

            var s, r;
            if(typeof value === 'number') {
                var v = Math.abs(value);
                s = r = this.legendFormatValue(value);

                if(typeof series.last === 'number') {
                    if(v > series.last) s += '<i class="fas fa-angle-up" style="width: 8px; text-align: center; overflow: hidden; vertical-align: middle;"></i>';
                    else if(v < series.last) s += '<i class="fas fa-angle-down" style="width: 8px; text-align: center; overflow: hidden; vertical-align: middle;"></i>';
                    else s += '<i class="fas fa-angle-left" style="width: 8px; text-align: center; overflow: hidden; vertical-align: middle;"></i>';
                }
                else s += '<i class="fas fa-angle-right" style="width: 8px; text-align: center; overflow: hidden; vertical-align: middle;"></i>';

                series.last = v;
            }
            else {
                if(value === null)
                    s = r = '';
                else
                    s = r = value;

                series.last = value;
            }
            */

            var s = this.legendFormatValue(value);

            // caching: do not update the update to show the same value again
            if(s === series.last_shown_value) return;
            series.last_shown_value = s;

            if(series.value !== null) series.value.innerText = s;
            if(series.user !== null) series.user.innerText = s;
        };

        this.legendSetDateString = function(date) {
            if(this.element_legend_childs.title_date !== null && date !== this.tmp.__last_shown_legend_date) {
                this.element_legend_childs.title_date.innerText = date;
                this.tmp.__last_shown_legend_date = date;
            }
        };

        this.legendSetTimeString = function(time) {
            if(this.element_legend_childs.title_time !== null && time !== this.tmp.__last_shown_legend_time) {
                this.element_legend_childs.title_time.innerText = time;
                this.tmp.__last_shown_legend_time = time;
            }
        };

        this.legendSetUnitsString = function(units) {
            if(this.element_legend_childs.title_units !== null && units !== this.tmp.__last_shown_legend_units) {
                this.element_legend_childs.title_units.innerText = units;
                this.tmp.__last_shown_legend_units = units;
            }
        };

        this.legendSetDateLast = {
            ms: 0,
            date: undefined,
            time: undefined
        };

        this.legendSetDate = function(ms) {
            if(typeof ms !== 'number') {
                this.legendShowUndefined();
                return;
            }

            if(this.legendSetDateLast.ms !== ms) {
                var d = new Date(ms);
                this.legendSetDateLast.ms = ms;
                this.legendSetDateLast.date = NETDATA.dateTime.localeDateString(d);
                this.legendSetDateLast.time = NETDATA.dateTime.localeTimeString(d);
            }

            this.legendSetDateString(this.legendSetDateLast.date);
            this.legendSetTimeString(this.legendSetDateLast.time);
            this.legendSetUnitsString(this.units_current)
        };

        this.legendShowUndefined = function() {
            this.legendSetDateString(this.legendPluginModuleString(false));
            this.legendSetTimeString(this.chart.context.toString());
            // this.legendSetUnitsString(' ');

            if(this.data && this.element_legend_childs.series !== null) {
                var labels = this.data.dimension_names;
                var i = labels.length;
                while(i--) {
                    var label = labels[i];

                    if(typeof label === 'undefined' || typeof this.element_legend_childs.series[label] === 'undefined') continue;
                    this.legendSetLabelValue(label, null);
                }
            }
        };

        this.legendShowLatestValues = function() {
            if(this.chart === null) return;
            if(this.selected) return;

            if(this.data === null || this.element_legend_childs.series === null) {
                this.legendShowUndefined();
                return;
            }

            var show_undefined = true;
            if(Math.abs(this.netdata_last - this.view_before) <= this.data_update_every)
                show_undefined = false;

            if(show_undefined) {
                this.legendShowUndefined();
                return;
            }

            this.legendSetDate(this.view_before);

            var labels = this.data.dimension_names;
            var i = labels.length;
            while(i--) {
                var label = labels[i];

                if(typeof label === 'undefined') continue;
                if(typeof this.element_legend_childs.series[label] === 'undefined') continue;

                if(show_undefined)
                    this.legendSetLabelValue(label, null);
                else
                    this.legendSetLabelValue(label, this.data.view_latest_values[i]);
            }
        };

        this.legendReset = function() {
            this.legendShowLatestValues();
        };

        // this should be called just ONCE per dimension per chart
        this.__chartDimensionColor = function(label) {
            this.chartPrepareColorPalette();

            if(typeof this.colors_assigned[label] === 'undefined') {

                if(this.colors_available.length === 0) {
                    var len;

                    // copy the custom colors
                    if(this.colors_custom !== null) {
                        len = this.colors_custom.length;
                        while (len--)
                            this.colors_available.unshift(this.colors_custom[len]);
                    }

                    // copy the standard palette colors
                    len = NETDATA.themes.current.colors.length;
                    while(len--)
                        this.colors_available.unshift(NETDATA.themes.current.colors[len]);
                }

                // assign a color to this dimension
                this.colors_assigned[label] = this.colors_available.shift();

                if(this.debug === true)
                    this.log('label "' + label + '" got color "' + this.colors_assigned[label]);
            }
            else {
                if(this.debug === true)
                    this.log('label "' + label + '" already has color "' + this.colors_assigned[label] + '"');
            }

            this.colors.push(this.colors_assigned[label]);
            return this.colors_assigned[label];
        };

        this.chartPrepareColorPalette = function() {
            var len;

            if(this.colors_custom !== null) return;

            if(this.debug === true)
                this.log("Preparing chart color palette");

            this.colors = [];
            this.colors_available = [];
            this.colors_custom = [];

            // add the standard colors
            len = NETDATA.themes.current.colors.length;
            while(len--)
                this.colors_available.unshift(NETDATA.themes.current.colors[len]);

            // add the user supplied colors
            var c = NETDATA.dataAttribute(this.element, 'colors', undefined);
            // this.log('read colors: ' + c);
            if(typeof c === 'string' && c.length > 0) {
                c = c.split(' ');
                len = c.length;
                while(len--) {
                    if(this.debug === true)
                        this.log("Adding custom color " + c[len].toString() + " to palette");

                    this.colors_custom.unshift(c[len]);
                    this.colors_available.unshift(c[len]);
                }
            }

            if(this.debug === true) {
                this.log("colors_custom:");
                this.log(this.colors_custom);
                this.log("colors_available:");
                this.log(this.colors_available);
            }
        };

        // get the ordered list of chart colors
        // this includes user defined colors
        this.chartCustomColors = function() {
            this.chartPrepareColorPalette();

            var colors;
            if(this.colors_custom.length)
                colors = this.colors_custom;
            else
                colors = this.colors;

            if(this.debug === true) {
                this.log("chartCustomColors() returns:");
                this.log(colors);
            }

            return colors;
        };

        // get the ordered list of chart ASSIGNED colors
        // (this returns only the colors that have been
        //  assigned to dimensions, prepended with any
        // custom colors defined)
        this.chartColors = function() {
            this.chartPrepareColorPalette();

            if(this.debug === true) {
                this.log("chartColors() returns:");
                this.log(this.colors);
            }

            return this.colors;
        };

        this.legendPluginModuleString = function(withContext) {
            var str = ' ';
            var context = '';

            if(typeof this.chart !== 'undefined') {
                if(withContext && typeof this.chart.context === 'string')
                    context = this.chart.context;

                if (typeof this.chart.plugin === 'string' && this.chart.plugin !== '') {
                    str = this.chart.plugin;
                    if (typeof this.chart.module === 'string' && this.chart.module !== '') {
                        str += '/' + this.chart.module;
                    }

                    if (withContext && context !== '')
                        str += ', ' + context;
                }
                else if (withContext && context !== '')
                    str = context;
            }

            return str;
        };

        this.legendResolutionTooltip = function () {
            if(!this.chart) return '';

            var collected = this.chart.update_every;
            var viewed = (this.data)?this.data.view_update_every:collected;

            if(collected === viewed)
                return "resolution " + NETDATA.seconds4human(collected);

            return "resolution " + NETDATA.seconds4human(viewed) + ", collected every " + NETDATA.seconds4human(collected);
        };

        this.legendUpdateDOM = function() {
            var needed = false, dim, keys, len, i;

            // check that the legend DOM is up to date for the downloaded dimensions
            if(typeof this.element_legend_childs.series !== 'object' || this.element_legend_childs.series === null) {
                // this.log('the legend does not have any series - requesting legend update');
                needed = true;
            }
            else if(this.data === null) {
                // this.log('the chart does not have any data - requesting legend update');
                needed = true;
            }
            else if(typeof this.element_legend_childs.series.labels_key === 'undefined') {
                needed = true;
            }
            else {
                var labels = this.data.dimension_names.toString();
                if(labels !== this.element_legend_childs.series.labels_key) {
                    needed = true;

                    if(this.debug === true)
                        this.log('NEW LABELS: "' + labels + '" NOT EQUAL OLD LABELS: "' + this.element_legend_childs.series.labels_key + '"');
                }
            }

            if(needed === false) {
                // make sure colors available
                this.chartPrepareColorPalette();

                // do we have to update the current values?
                // we do this, only when the visible chart is current
                if(Math.abs(this.netdata_last - this.view_before) <= this.data_update_every) {
                    if(this.debug === true)
                        this.log('chart is in latest position... updating values on legend...');

                    //var labels = this.data.dimension_names;
                    //var i = labels.length;
                    //while(i--)
                    //  this.legendSetLabelValue(labels[i], this.data.latest_values[i]);
                }
                return;
            }
            if(this.colors === null) {
                // this is the first time we update the chart
                // let's assign colors to all dimensions
                if(this.library.track_colors() === true) {
                    keys = Object.keys(this.chart.dimensions);
                    len = keys.length;
                    for(i = 0; i < len ;i++)
                        this.__chartDimensionColor(this.chart.dimensions[keys[i]].name);
                }
            }
            // we will re-generate the colors for the chart
            // based on the dimensions this result has data for
            this.colors = [];

            if(this.debug === true)
                this.log('updating Legend DOM');

            // mark all dimensions as invalid
            this.dimensions_visibility.invalidateAll();

            var genLabel = function(state, parent, dim, name, count) {
                var color = state.__chartDimensionColor(name);

                var user_element = null;
                var user_id = NETDATA.dataAttribute(state.element, 'show-value-of-' + name.toLowerCase() + '-at', null);
                if(user_id === null)
                    user_id = NETDATA.dataAttribute(state.element, 'show-value-of-' + dim.toLowerCase() + '-at', null);
                if(user_id !== null) {
                    user_element = document.getElementById(user_id) || null;
                    if (user_element === null)
                        state.log('Cannot find element with id: ' + user_id);
                }

                state.element_legend_childs.series[name] = {
                    name: document.createElement('span'),
                    value: document.createElement('span'),
                    user: user_element,
                    last: null,
                    last_shown_value: null
                };

                var label = state.element_legend_childs.series[name];

                // create the dimension visibility tracking for this label
                state.dimensions_visibility.dimensionAdd(name, label.name, label.value, color);

                var rgb = NETDATA.colorHex2Rgb(color);
                label.name.innerHTML = '<table class="netdata-legend-name-table-'
                    + state.chart.chart_type
                    + '" style="background-color: '
                    + 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + NETDATA.options.current['color_fill_opacity_' + state.chart.chart_type] + ') !important'
                    + '"><tr class="netdata-legend-name-tr"><td class="netdata-legend-name-td"></td></tr></table>';

                var text = document.createTextNode(' ' + name);
                label.name.appendChild(text);

                if(count > 0)
                    parent.appendChild(document.createElement('br'));

                parent.appendChild(label.name);
                parent.appendChild(label.value);
            };

            var content = document.createElement('div');

            if(this.element_chart === null) {
                this.element_chart = document.createElement('div');
                this.element_chart.id = this.library_name + '-' + this.uuid + '-chart';
                this.element.appendChild(this.element_chart);

                if(this.hasLegend() === true)
                    this.element_chart.className = 'netdata-chart-with-legend-right netdata-' + this.library_name + '-chart-with-legend-right';
                else
                    this.element_chart.className = ' netdata-chart netdata-' + this.library_name + '-chart';
            }

            if(this.hasLegend() === true) {
                if(this.element_legend === null) {
                    this.element_legend = document.createElement('div');
                    this.element_legend.className = 'netdata-chart-legend netdata-' + this.library_name + '-legend';
                    this.element.appendChild(this.element_legend);
                }
                else
                    this.element_legend.innerHTML = '';

                this.element_legend_childs = {
                    content: content,
                    resize_handler: null,
                    toolbox: null,
                    toolbox_left: null,
                    toolbox_right: null,
                    toolbox_reset: null,
                    toolbox_zoomin: null,
                    toolbox_zoomout: null,
                    toolbox_volume: null,
                    title_date: document.createElement('span'),
                    title_time: document.createElement('span'),
                    title_units: document.createElement('span'),
                    perfect_scroller: document.createElement('div'),
                    series: {}
                };

                if(NETDATA.options.current.legend_toolbox === true && this.library.toolboxPanAndZoom !== null) {
                    this.element_legend_childs.toolbox = document.createElement('div');
                    this.element_legend_childs.toolbox_left = document.createElement('div');
                    this.element_legend_childs.toolbox_right = document.createElement('div');
                    this.element_legend_childs.toolbox_reset = document.createElement('div');
                    this.element_legend_childs.toolbox_zoomin = document.createElement('div');
                    this.element_legend_childs.toolbox_zoomout = document.createElement('div');
                    this.element_legend_childs.toolbox_volume = document.createElement('div');

                    var get_pan_and_zoom_step = function(event) {
                        if (event.ctrlKey)
                            return NETDATA.options.current.pan_and_zoom_factor * NETDATA.options.current.pan_and_zoom_factor_multiplier_control;

                        else if (event.shiftKey)
                            return NETDATA.options.current.pan_and_zoom_factor * NETDATA.options.current.pan_and_zoom_factor_multiplier_shift;

                        else if (event.altKey)
                            return NETDATA.options.current.pan_and_zoom_factor * NETDATA.options.current.pan_and_zoom_factor_multiplier_alt;

                        else
                            return NETDATA.options.current.pan_and_zoom_factor;
                    };

                    this.element_legend_childs.toolbox.className += ' netdata-legend-toolbox';
                    this.element.appendChild(this.element_legend_childs.toolbox);

                    this.element_legend_childs.toolbox_left.className += ' netdata-legend-toolbox-button';
                    this.element_legend_childs.toolbox_left.innerHTML = '<i class="fas fa-backward"></i>';
                    this.element_legend_childs.toolbox.appendChild(this.element_legend_childs.toolbox_left);
                    this.element_legend_childs.toolbox_left.onclick = function(e) {
                        e.preventDefault();

                        var step = (that.view_before - that.view_after) * get_pan_and_zoom_step(e);
                        var before = that.view_before - step;
                        var after = that.view_after - step;
                        if(after >= that.netdata_first)
                            that.library.toolboxPanAndZoom(that, after, before);
                    };
                    if(NETDATA.options.current.show_help === true)
                        $(this.element_legend_childs.toolbox_left).popover({
                        container: "body",
                        animation: false,
                        html: true,
                        trigger: 'hover',
                        placement: 'bottom',
                        delay: { show: NETDATA.options.current.show_help_delay_show_ms, hide: NETDATA.options.current.show_help_delay_hide_ms },
                        title: 'Pan Left',
                        content: 'Pan the chart to the left. You can also <b>drag it</b> with your mouse or your finger (on touch devices).<br/><small>Help can be disabled from the settings.</small>'
                    });


                    this.element_legend_childs.toolbox_reset.className += ' netdata-legend-toolbox-button';
                    this.element_legend_childs.toolbox_reset.innerHTML = '<i class="fas fa-play"></i>';
                    this.element_legend_childs.toolbox.appendChild(this.element_legend_childs.toolbox_reset);
                    this.element_legend_childs.toolbox_reset.onclick = function(e) {
                        e.preventDefault();
                        NETDATA.resetAllCharts(that);
                    };
                    if(NETDATA.options.current.show_help === true)
                        $(this.element_legend_childs.toolbox_reset).popover({
                        container: "body",
                        animation: false,
                        html: true,
                        trigger: 'hover',
                        placement: 'bottom',
                        delay: { show: NETDATA.options.current.show_help_delay_show_ms, hide: NETDATA.options.current.show_help_delay_hide_ms },
                        title: 'Chart Reset',
                        content: 'Reset all the charts to their default auto-refreshing state. You can also <b>double click</b> the chart contents with your mouse or your finger (on touch devices).<br/><small>Help can be disabled from the settings.</small>'
                    });

                    this.element_legend_childs.toolbox_right.className += ' netdata-legend-toolbox-button';
                    this.element_legend_childs.toolbox_right.innerHTML = '<i class="fas fa-forward"></i>';
                    this.element_legend_childs.toolbox.appendChild(this.element_legend_childs.toolbox_right);
                    this.element_legend_childs.toolbox_right.onclick = function(e) {
                        e.preventDefault();
                        var step = (that.view_before - that.view_after) * get_pan_and_zoom_step(e);
                        var before = that.view_before + step;
                        var after = that.view_after + step;
                        if(before <= that.netdata_last)
                            that.library.toolboxPanAndZoom(that, after, before);
                    };
                    if(NETDATA.options.current.show_help === true)
                        $(this.element_legend_childs.toolbox_right).popover({
                        container: "body",
                        animation: false,
                        html: true,
                        trigger: 'hover',
                        placement: 'bottom',
                        delay: { show: NETDATA.options.current.show_help_delay_show_ms, hide: NETDATA.options.current.show_help_delay_hide_ms },
                        title: 'Pan Right',
                        content: 'Pan the chart to the right. You can also <b>drag it</b> with your mouse or your finger (on touch devices).<br/><small>Help, can be disabled from the settings.</small>'
                    });


                    this.element_legend_childs.toolbox_zoomin.className += ' netdata-legend-toolbox-button';
                    this.element_legend_childs.toolbox_zoomin.innerHTML = '<i class="fas fa-plus"></i>';
                    this.element_legend_childs.toolbox.appendChild(this.element_legend_childs.toolbox_zoomin);
                    this.element_legend_childs.toolbox_zoomin.onclick = function(e) {
                        e.preventDefault();
                        var dt = ((that.view_before - that.view_after) * (get_pan_and_zoom_step(e) * 0.8) / 2);
                        var before = that.view_before - dt;
                        var after = that.view_after + dt;
                        that.library.toolboxPanAndZoom(that, after, before);
                    };
                    if(NETDATA.options.current.show_help === true)
                        $(this.element_legend_childs.toolbox_zoomin).popover({
                        container: "body",
                        animation: false,
                        html: true,
                        trigger: 'hover',
                        placement: 'bottom',
                        delay: { show: NETDATA.options.current.show_help_delay_show_ms, hide: NETDATA.options.current.show_help_delay_hide_ms },
                        title: 'Chart Zoom In',
                        content: 'Zoom in the chart. You can also press SHIFT and select an area of the chart, or press SHIFT or ALT and use the mouse wheel or 2-finger touchpad scroll to zoom in or out.<br/><small>Help, can be disabled from the settings.</small>'
                    });

                    this.element_legend_childs.toolbox_zoomout.className += ' netdata-legend-toolbox-button';
                    this.element_legend_childs.toolbox_zoomout.innerHTML = '<i class="fas fa-minus"></i>';
                    this.element_legend_childs.toolbox.appendChild(this.element_legend_childs.toolbox_zoomout);
                    this.element_legend_childs.toolbox_zoomout.onclick = function(e) {
                        e.preventDefault();
                        var dt = (((that.view_before - that.view_after) / (1.0 - (get_pan_and_zoom_step(e) * 0.8)) - (that.view_before - that.view_after)) / 2);
                        var before = that.view_before + dt;
                        var after = that.view_after - dt;

                        that.library.toolboxPanAndZoom(that, after, before);
                    };
                    if(NETDATA.options.current.show_help === true)
                        $(this.element_legend_childs.toolbox_zoomout).popover({
                        container: "body",
                        animation: false,
                        html: true,
                        trigger: 'hover',
                        placement: 'bottom',
                        delay: { show: NETDATA.options.current.show_help_delay_show_ms, hide: NETDATA.options.current.show_help_delay_hide_ms },
                        title: 'Chart Zoom Out',
                        content: 'Zoom out the chart. You can also press SHIFT or ALT and use the mouse wheel, or 2-finger touchpad scroll to zoom in or out.<br/><small>Help, can be disabled from the settings.</small>'
                    });

                    //this.element_legend_childs.toolbox_volume.className += ' netdata-legend-toolbox-button';
                    //this.element_legend_childs.toolbox_volume.innerHTML = '<i class="fas fa-sort-amount-down"></i>';
                    //this.element_legend_childs.toolbox_volume.title = 'Visible Volume';
                    //this.element_legend_childs.toolbox.appendChild(this.element_legend_childs.toolbox_volume);
                    //this.element_legend_childs.toolbox_volume.onclick = function(e) {
                        //e.preventDefault();
                        //alert('clicked toolbox_volume on ' + that.id);
                    //}
                }

                if(NETDATA.options.current.resize_charts === true) {
                    this.element_legend_childs.resize_handler = document.createElement('div');

                    this.element_legend_childs.resize_handler.className += " netdata-legend-resize-handler";
                    this.element_legend_childs.resize_handler.innerHTML = '<i class="fas fa-sort"></i>';
                    this.element.appendChild(this.element_legend_childs.resize_handler);
                    if (NETDATA.options.current.show_help === true)
                        $(this.element_legend_childs.resize_handler).popover({
                            container: "body",
                            animation: false,
                            html: true,
                            trigger: 'hover',
                            placement: 'bottom',
                            delay: {
                                show: NETDATA.options.current.show_help_delay_show_ms,
                                hide: NETDATA.options.current.show_help_delay_hide_ms
                            },
                            title: 'Chart Resize',
                            content: 'Drag this point with your mouse or your finger (on touch devices), to resize the chart vertically. You can also <b>double click it</b> or <b>double tap it</b> to reset between 2 states: the default and the one that fits all the values.<br/><small>Help, can be disabled from the settings.</small>'
                        });

                    // mousedown event
                    this.element_legend_childs.resize_handler.onmousedown =
                        function (e) {
                            that.resizeHandler(e);
                        };

                    // touchstart event
                    this.element_legend_childs.resize_handler.addEventListener('touchstart', function (e) {
                        that.resizeHandler(e);
                    }, false);
                }

                if(this.chart) {
                    this.element_legend_childs.title_date.title = this.legendPluginModuleString(true);
                    this.element_legend_childs.title_time.title = this.legendResolutionTooltip();
                }

                this.element_legend_childs.title_date.className += " netdata-legend-title-date";
                this.element_legend.appendChild(this.element_legend_childs.title_date);
                this.tmp.__last_shown_legend_date = undefined;

                this.element_legend.appendChild(document.createElement('br'));

                this.element_legend_childs.title_time.className += " netdata-legend-title-time";
                this.element_legend.appendChild(this.element_legend_childs.title_time);
                this.tmp.__last_shown_legend_time = undefined;

                this.element_legend.appendChild(document.createElement('br'));

                this.element_legend_childs.title_units.className += " netdata-legend-title-units";
                this.element_legend_childs.title_units.innerText = this.units_current;
                this.element_legend.appendChild(this.element_legend_childs.title_units);
                this.tmp.__last_shown_legend_units = undefined;

                this.element_legend.appendChild(document.createElement('br'));

                this.element_legend_childs.perfect_scroller.className = 'netdata-legend-series';
                this.element_legend.appendChild(this.element_legend_childs.perfect_scroller);

                content.className = 'netdata-legend-series-content';
                this.element_legend_childs.perfect_scroller.appendChild(content);

                this.element_legend_childs.content = content;

                if(NETDATA.options.current.show_help === true)
                    $(content).popover({
                    container: "body",
                    animation: false,
                    html: true,
                    trigger: 'hover',
                    placement: 'bottom',
                    title: 'Chart Legend',
                    delay: { show: NETDATA.options.current.show_help_delay_show_ms, hide: NETDATA.options.current.show_help_delay_hide_ms },
                    content: 'You can click or tap on the values or the labels to select dimensions. By pressing SHIFT or CONTROL, you can enable or disable multiple dimensions.<br/><small>Help, can be disabled from the settings.</small>'
                });
            }
            else {
                this.element_legend_childs = {
                    content: content,
                    resize_handler: null,
                    toolbox: null,
                    toolbox_left: null,
                    toolbox_right: null,
                    toolbox_reset: null,
                    toolbox_zoomin: null,
                    toolbox_zoomout: null,
                    toolbox_volume: null,
                    title_date: null,
                    title_time: null,
                    title_units: null,
                    perfect_scroller: null,
                    series: {}
                };
            }

            if(this.data) {
                this.element_legend_childs.series.labels_key = this.data.dimension_names.toString();
                if(this.debug === true)
                    this.log('labels from data: "' + this.element_legend_childs.series.labels_key + '"');

                for(i = 0, len = this.data.dimension_names.length; i < len ;i++) {
                    genLabel(this, content, this.data.dimension_ids[i], this.data.dimension_names[i], i);
                }
            }
            else {
                var tmp = [];
                keys = Object.keys(this.chart.dimensions);
                for(i = 0, len = keys.length; i < len ;i++) {
                    dim = keys[i];
                    tmp.push(this.chart.dimensions[dim].name);
                    genLabel(this, content, dim, this.chart.dimensions[dim].name, i);
                }
                this.element_legend_childs.series.labels_key = tmp.toString();
                if(this.debug === true)
                    this.log('labels from chart: "' + this.element_legend_childs.series.labels_key + '"');
            }

            // create a hidden div to be used for hidding
            // the original legend of the chart library
            var el = document.createElement('div');
            if(this.element_legend !== null)
                this.element_legend.appendChild(el);
            el.style.display = 'none';

            this.element_legend_childs.hidden = document.createElement('div');
            el.appendChild(this.element_legend_childs.hidden);

            if(this.element_legend_childs.perfect_scroller !== null) {
                Ps.initialize(this.element_legend_childs.perfect_scroller, {
                    wheelSpeed: 0.2,
                    wheelPropagation: true,
                    swipePropagation: true,
                    minScrollbarLength: null,
                    maxScrollbarLength: null,
                    useBothWheelAxes: false,
                    suppressScrollX: true,
                    suppressScrollY: false,
                    scrollXMarginOffset: 0,
                    scrollYMarginOffset: 0,
                    theme: 'default'
                });
                Ps.update(this.element_legend_childs.perfect_scroller);
            }

            this.legendShowLatestValues();
        };

        this.hasLegend = function() {
            if(typeof this.tmp.___hasLegendCache___ !== 'undefined')
                return this.tmp.___hasLegendCache___;

            var leg = false;
            if(this.library && this.library.legend(this) === 'right-side')
                leg = NETDATA.dataAttributeBoolean(this.element, 'legend', true);

            this.tmp.___hasLegendCache___ = leg;
            return leg;
        };

        this.legendWidth = function() {
            return (this.hasLegend())?140:0;
        };

        this.legendHeight = function() {
            return $(this.element).height();
        };

        this.chartWidth = function() {
            return $(this.element).width() - this.legendWidth();
        };

        this.chartHeight = function() {
            return $(this.element).height();
        };

        this.chartPixelsPerPoint = function() {
            // force an options provided detail
            var px = this.pixels_per_point;

            if(this.library && px < this.library.pixels_per_point(this))
                px = this.library.pixels_per_point(this);

            if(px < NETDATA.options.current.pixels_per_point)
                px = NETDATA.options.current.pixels_per_point;

            return px;
        };

        this.needsRecreation = function() {
            var ret = (
                    this.chart_created === true
                    && this.library
                    && this.library.autoresize() === false
                    && this.tm.last_resized < NETDATA.options.last_page_resize
                );

            if(this.debug === true)
                this.log('needsRecreation(): ' + ret.toString() + ', chart_created = ' + this.chart_created.toString());

            return ret;
        };

        this.chartDataUniqueID = function() {
            return this.id + ',' + this.library_name + ',' + this.dimensions + ',' + this.chartURLOptions();
        };

        this.chartURLOptions = function() {
            var ret = '';

            if(this.override_options !== null)
                ret = this.override_options.toString();
            else
                ret = this.library.options(this);

            if(this.append_options !== null)
                ret += '|' + this.append_options.toString();

            ret += '|jsonwrap';

            if(NETDATA.options.current.eliminate_zero_dimensions === true)
                ret += '|nonzero';

            return ret;
        };

        this.chartURL = function() {
            var after, before, points_multiplier = 1;
            if(NETDATA.globalPanAndZoom.isActive()) {
                if(this.current.force_before_ms !== null && this.current.force_after_ms !== null) {
                    this.tm.pan_and_zoom_seq = 0;

                    before = Math.round(this.current.force_before_ms / 1000);
                    after  = Math.round(this.current.force_after_ms / 1000);
                    this.view_after = after * 1000;
                    this.view_before = before * 1000;

                    if(NETDATA.options.current.pan_and_zoom_data_padding === true) {
                        this.requested_padding = Math.round((before - after) / 2);
                        after -= this.requested_padding;
                        before += this.requested_padding;
                        this.requested_padding *= 1000;
                        points_multiplier = 2;
                    }

                    this.current.force_before_ms = null;
                    this.current.force_after_ms = null;
                }
                else {
                    this.tm.pan_and_zoom_seq = NETDATA.globalPanAndZoom.seq;

                    after = Math.round(NETDATA.globalPanAndZoom.force_after_ms / 1000);
                    before = Math.round(NETDATA.globalPanAndZoom.force_before_ms / 1000);
                    this.view_after = after * 1000;
                    this.view_before = before * 1000;

                    this.requested_padding = null;
                    points_multiplier = 1;
                }
            }
            else {
                this.tm.pan_and_zoom_seq = 0;

                before = this.before;
                after  = this.after;
                this.view_after = after * 1000;
                this.view_before = before * 1000;

                this.requested_padding = null;
                points_multiplier = 1;
            }

            this.requested_after = after * 1000;
            this.requested_before = before * 1000;

            var data_points;
            if(NETDATA.options.force_data_points !== 0) {
                data_points = NETDATA.options.force_data_points;
                this.data_points = data_points;
            }
            else {
                this.data_points = this.points || Math.round(this.chartWidth() / this.chartPixelsPerPoint());
                data_points = this.data_points * points_multiplier;
            }

            // build the data URL
            this.data_url = this.host + this.chart.data_url;
            this.data_url += "&format="  + this.library.format();
            this.data_url += "&points="  + (data_points).toString();
            this.data_url += "&group="   + this.method;
            this.data_url += "&options=" + this.chartURLOptions();

            if(after)
                this.data_url += "&after="  + after.toString();

            if(before)
                this.data_url += "&before=" + before.toString();

            if(this.dimensions)
                this.data_url += "&dimensions=" + this.dimensions;

            if(NETDATA.options.debug.chart_data_url === true || this.debug === true)
                this.log('chartURL(): ' + this.data_url + ' WxH:' + this.chartWidth() + 'x' + this.chartHeight() + ' points: ' + data_points.toString() + ' library: ' + this.library_name);
        };

        this.redrawChart = function() {
            if(this.data !== null)
                this.updateChartWithData(this.data);
        };

        this.updateChartWithData = function(data) {
            if(this.debug === true)
                this.log('updateChartWithData() called.');

            // this may force the chart to be re-created
            resizeChart();

            this.data = data;

            var started = Date.now();
            var view_update_every = data.view_update_every * 1000;


            if(this.data_update_every !== view_update_every) {
                if(this.element_legend_childs.title_time)
                    this.element_legend_childs.title_time.title = this.legendResolutionTooltip();
            }

            // if the result is JSON, find the latest update-every
            this.data_update_every = view_update_every;
            this.data_after = data.after * 1000;
            this.data_before = data.before * 1000;
            this.netdata_first = data.first_entry * 1000;
            this.netdata_last = data.last_entry * 1000;
            this.data_points = data.points;

            data.state = this;

            if(NETDATA.options.current.pan_and_zoom_data_padding === true && this.requested_padding !== null) {
                if(this.view_after < this.data_after) {
                    // console.log('adjusting view_after from ' + this.view_after + ' to ' + this.data_after);
                    this.view_after = this.data_after;
                }

                if(this.view_before > this.data_before) {
                    // console.log('adjusting view_before from ' + this.view_before + ' to ' + this.data_before);
                    this.view_before = this.data_before;
                }
            }
            else {
                this.view_after = this.data_after;
                this.view_before = this.data_before;
            }

            if(this.debug === true) {
                this.log('UPDATE No ' + this.updates_counter + ' COMPLETED');

                if(this.current.force_after_ms)
                    this.log('STATUS: forced    : ' + (this.current.force_after_ms / 1000).toString() + ' - ' + (this.current.force_before_ms / 1000).toString());
                else
                    this.log('STATUS: forced    : unset');

                this.log('STATUS: requested : ' + (this.requested_after / 1000).toString() + ' - ' + (this.requested_before / 1000).toString());
                this.log('STATUS: downloaded: ' + (this.data_after / 1000).toString() + ' - ' + (this.data_before / 1000).toString());
                this.log('STATUS: rendered  : ' + (this.view_after / 1000).toString() + ' - ' + (this.view_before / 1000).toString());
                this.log('STATUS: points    : ' + (this.data_points).toString());
            }

            if(this.data_points === 0) {
                noDataToShow();
                return;
            }

            if(this.updates_since_last_creation >= this.library.max_updates_to_recreate()) {
                if(this.debug === true)
                    this.log('max updates of ' + this.updates_since_last_creation.toString() + ' reached. Forcing re-generation.');

                init('force');
                return;
            }

            // check and update the legend
            this.legendUpdateDOM();

            if(this.chart_created === true
                && typeof this.library.update === 'function') {

                if(this.debug === true)
                    this.log('updating chart...');

                if(callChartLibraryUpdateSafely(data) === false)
                    return;
            }
            else {
                if(this.debug === true)
                    this.log('creating chart...');

                if(callChartLibraryCreateSafely(data) === false)
                    return;
            }
            hideMessage();
            this.legendShowLatestValues();
            if(this.selected === true)
                NETDATA.globalSelectionSync.stop();

            // update the performance counters
            var now = Date.now();
            this.tm.last_updated = now;

            // don't update last_autorefreshed if this chart is
            // forced to be updated with global PanAndZoom
            if(NETDATA.globalPanAndZoom.isActive())
                this.tm.last_autorefreshed = 0;
            else {
                if(NETDATA.options.current.parallel_refresher === true && NETDATA.options.current.concurrent_refreshes === true)
                    this.tm.last_autorefreshed = now - (now % this.data_update_every);
                else
                    this.tm.last_autorefreshed = now;
            }

            this.refresh_dt_ms = now - started;
            NETDATA.options.auto_refresher_fast_weight += this.refresh_dt_ms;

            if(this.refresh_dt_element !== null)
                this.refresh_dt_element.innerText = this.refresh_dt_ms.toString();
        };

        this.getSnapshotData = function(key) {
            if(this.debug === true)
                this.log('updating from snapshot: ' + key);

            if(typeof netdataSnapshotData.data[key] === 'undefined') {
                this.log('snapshot does not include data for key "' + key + '"');
                return null;
            }

            if(typeof netdataSnapshotData.data[key] !== 'string') {
                this.log('snapshot data for key "' + key + '" is not string');
                return null;
            }

            var uncompressed;
            try {
                uncompressed = netdataSnapshotData.uncompress(netdataSnapshotData.data[key]);

                if(uncompressed === null) {
                    this.log('uncompressed snapshot data for key ' + key + ' is null');
                    return null;
                }

                if(typeof uncompressed === 'undefined') {
                    this.log('uncompressed snapshot data for key ' + key + ' is undefined');
                    return null;
                }
            }
            catch(e) {
                this.log('decompression of snapshot data for key ' + key + ' failed');
                console.log(e);
                uncompressed = null;
            }

            if(typeof uncompressed !== 'string') {
                this.log('uncompressed snapshot data for key ' + key + ' is not string');
                return null;
            }

            var data;
            try {
                data = JSON.parse(uncompressed);
            }
            catch(e) {
                this.log('parsing snapshot data for key ' + key + ' failed');
                console.log(e);
                data = null;
            }

            return data;
        };

        this.updateChart = function(callback) {
            if(this.debug === true)
                this.log('updateChart()');

            if(this.fetching_data === true) {
                if(this.debug === true)
                    this.log('I am already updating...');

                if(typeof callback === 'function')
                    return callback(false, 'already running');

                return;
            }

            // due to late initialization of charts and libraries
            // we need to check this too
            if(this.enabled === false) {
                if(this.debug === true)
                    this.log('I am not enabled');

                if(typeof callback === 'function')
                    return callback(false, 'not enabled');

                return;
            }

            if(canBeRendered() === false) {
                if(typeof callback === 'function')
                    return callback(false, 'cannot be rendered');

                return;
            }

            if(that.dom_created !== true)
                createDOM();

            if(this.chart === null)
                return this.getChart(function() {
                    return that.updateChart(callback);
                });

            if(this.library.initialized === false) {
                if(this.library.enabled === true) {
                    return this.library.initialize(function () {
                        return that.updateChart(callback);
                    });
                }
                else {
                    error('chart library "' + this.library_name + '" is not available.');

                    if(typeof callback === 'function')
                        return callback(false, 'library not available');

                    return;
                }
            }

            this.clearSelection();
            this.chartURL();

            NETDATA.statistics.refreshes_total++;
            NETDATA.statistics.refreshes_active++;

            if(NETDATA.statistics.refreshes_active > NETDATA.statistics.refreshes_active_max)
                NETDATA.statistics.refreshes_active_max = NETDATA.statistics.refreshes_active;

            var ok = false;
            this.fetching_data = true;

            if(netdataSnapshotData !== null) {
                var key = this.chartDataUniqueID();
                var data = this.getSnapshotData(key);
                if (data !== null) {
                    ok = true;
                    this.updateChartWithData(data);
                }
                else {
                    ok = false;
                    error('cannot get data from snapshot for key: "' + key + '"');
                    that.tm.last_autorefreshed = Date.now();
                }

                NETDATA.statistics.refreshes_active--;
                this.fetching_data = false;

                if(typeof callback === 'function')
                    callback(ok, 'snapshot');

                return;
            }

            if(this.debug === true)
                this.log('updating from ' + this.data_url);

            this.xhr = $.ajax( {
                url: this.data_url,
                cache: false,
                async: true,
                headers: {
                    'Cache-Control': 'no-cache, no-store',
                    'Pragma': 'no-cache'
                },
                xhrFields: { withCredentials: true } // required for the cookie
            })
            .done(function(data) {
                that.xhr = undefined;
                that.retries_on_data_failures = 0;
                ok = true;

                if(that.debug === true)
                    that.log('data received. updating chart.');

                that.updateChartWithData(data);
            })
            .fail(function(msg) {
                that.xhr = undefined;

                if(msg.statusText !== 'abort') {
                    that.retries_on_data_failures++;
                    if(that.retries_on_data_failures > NETDATA.options.current.retries_on_data_failures) {
                        // that.log('failed ' + that.retries_on_data_failures.toString() + ' times - giving up');
                        that.retries_on_data_failures = 0;
                        error('data download failed for url: ' + that.data_url);
                    }
                    else {
                        that.tm.last_autorefreshed = Date.now();
                        // that.log('failed ' + that.retries_on_data_failures.toString() + ' times, but I will retry');
                    }
                }
            })
            .always(function() {
                that.xhr = undefined;

                NETDATA.statistics.refreshes_active--;
                that.fetching_data = false;

                if(typeof callback === 'function')
                    return callback(ok, 'download');
            });
        };

        var __isVisible = function() {
            if(NETDATA.options.current.update_only_visible === false)
                return true;

            // tolerance is the number of pixels a chart can be off-screen
            // to consider it as visible and refresh it as if was visible
            var tolerance = 0;

            that.tm.last_visible_check = Date.now();

            var rect = that.element.getBoundingClientRect();

            var screenTop = window.scrollY;
            var screenBottom = screenTop + window.innerHeight;

            var chartTop = rect.top + screenTop;
            var chartBottom = chartTop + rect.height;

            return !(rect.width === 0 || rect.height === 0 || chartBottom + tolerance < screenTop || chartTop - tolerance > screenBottom);
        };

        this.isVisible = function(nocache) {
            // this.log('last_visible_check: ' + this.tm.last_visible_check + ', last_page_scroll: ' + NETDATA.options.last_page_scroll);

            // caching - we do not evaluate the charts visibility
            // if the page has not been scrolled since the last check
            if((typeof nocache === 'undefined' || nocache === false)
                && typeof this.tmp.___isVisible___ !== 'undefined'
                && this.tm.last_visible_check > NETDATA.options.last_page_scroll)
                return this.tmp.___isVisible___;

            this.tmp.___isVisible___ = __isVisible();
            if(this.tmp.___isVisible___ === true) unhideChart();
            else hideChart();

            return this.tmp.___isVisible___;
        };

        this.isAutoRefreshable = function() {
            return (this.current.autorefresh);
        };

        this.canBeAutoRefreshed = function() {
            if(this.enabled === false) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed() -> not enabled');

                return false;
            }

            if(this.running === true) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed() -> already running');

                return false;
            }

            if(this.library === null || this.library.enabled === false) {
                error('charting library "' + this.library_name + '" is not available');
                if(this.debug === true)
                    this.log('canBeAutoRefreshed() -> chart library ' + this.library_name + ' is not available');

                return false;
            }

            if(this.isVisible() === false) {
                if(NETDATA.options.debug.visibility === true || this.debug === true)
                    this.log('canBeAutoRefreshed() -> not visible');

                return false;
            }

            var now = Date.now();

            if(this.current.force_update_at !== 0 && this.current.force_update_at < now) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed() -> timed force update - allowing this update');

                this.current.force_update_at = 0;
                return true;
            }

            if(this.isAutoRefreshable() === false) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed() -> not auto-refreshable');

                return false;
            }

            // allow the first update, even if the page is not visible
            if(NETDATA.options.page_is_visible === false && this.updates_counter && this.updates_since_last_unhide) {
                if(NETDATA.options.debug.focus === true || this.debug === true)
                    this.log('canBeAutoRefreshed() -> not the first update, and page does not have focus');

                return false;
            }

            if(this.needsRecreation() === true) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed() -> needs re-creation.');

                return true;
            }

            if(NETDATA.options.auto_refresher_stop_until >= now) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed() -> stopped until is in future.');

                return false;
            }

            // options valid only for autoRefresh()
            if(NETDATA.globalPanAndZoom.isActive()) {
                if(NETDATA.globalPanAndZoom.shouldBeAutoRefreshed(this)) {
                    if(this.debug === true)
                        this.log('canBeAutoRefreshed(): global panning: I need an update.');

                    return true;
                }
                else {
                    if(this.debug === true)
                        this.log('canBeAutoRefreshed(): global panning: I am already up to date.');

                    return false;
                }
            }

            if(this.selected === true) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed(): I have a selection in place.');

                return false;
            }

            if(this.paused === true) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed(): I am paused.');

                return false;
            }

            if(now - this.tm.last_autorefreshed >= this.data_update_every) {
                if(this.debug === true)
                    this.log('canBeAutoRefreshed(): It is time to update me.');

                return true;
            }

            return false;
        };

        this.autoRefresh = function(callback) {
            var state = that;

            if(state.canBeAutoRefreshed() === true && state.running === false) {

                state.running = true;
                state.updateChart(function() {
                    state.running = false;

                    if(typeof callback === 'function')
                        return callback();
                });
            }
            else {
                if(typeof callback === 'function')
                    return callback();
            }
        };

        this.__defaultsFromDownloadedChart = function(chart) {
            this.chart = chart;
            this.chart_url = chart.url;
            this.data_update_every = chart.update_every * 1000;
            this.data_points = Math.round(this.chartWidth() / this.chartPixelsPerPoint());
            this.tm.last_info_downloaded = Date.now();

            if(this.title === null)
                this.title = chart.title;

            if(this.units === null) {
                this.units = chart.units;
                this.units_current = this.units;
            }
        };

        // fetch the chart description from the netdata server
        this.getChart = function(callback) {
            this.chart = NETDATA.chartRegistry.get(this.host, this.id);
            if(this.chart) {
                this.__defaultsFromDownloadedChart(this.chart);

                if(typeof callback === 'function')
                    return callback();
            }
            else if(netdataSnapshotData !== null) {
                // console.log(this);
                // console.log(NETDATA.chartRegistry);
                NETDATA.error(404, 'host: ' + this.host + ', chart: ' +  this.id);
                error('chart not found in snapshot');

                if(typeof callback === 'function')
                    return callback();
            }
            else {
                this.chart_url = "/api/v1/chart?chart=" + this.id;

                if(this.debug === true)
                    this.log('downloading ' + this.chart_url);

                $.ajax( {
                    url:  this.host + this.chart_url,
                    cache: false,
                    async: true,
                    xhrFields: { withCredentials: true } // required for the cookie
                })
                .done(function(chart) {
                    chart.url = that.chart_url;
                    that.__defaultsFromDownloadedChart(chart);
                    NETDATA.chartRegistry.add(that.host, that.id, chart);
                })
                .fail(function() {
                    NETDATA.error(404, that.chart_url);
                    error('chart not found on url "' + that.chart_url + '"');
                })
                .always(function() {
                    if(typeof callback === 'function')
                        return callback();
                });
            }
        };

        // ============================================================================================================
        // INITIALIZATION

        initDOM();
        init('fast');
    };

    NETDATA.resetAllCharts = function(state) {
        // first clear the global selection sync
        // to make sure no chart is in selected state
        NETDATA.globalSelectionSync.stop();

        // there are 2 possibilities here
        // a. state is the global Pan and Zoom master
        // b. state is not the global Pan and Zoom master
        var master = true;
        if(NETDATA.globalPanAndZoom.isMaster(state) === false)
            master = false;

        // clear the global Pan and Zoom
        // this will also refresh the master
        // and unblock any charts currently mirroring the master
        NETDATA.globalPanAndZoom.clearMaster();

        // if we were not the master, reset our status too
        // this is required because most probably the mouse
        // is over this chart, blocking it from auto-refreshing
        if(master === false && (state.paused === true || state.selected === true))
            state.resetChart();
    };

    // get or create a chart state, given a DOM element
    NETDATA.chartState = function(element) {
        var self = $(element);

        var state = self.data('netdata-state-object') || null;
        if(state === null) {
            state = new chartState(element);
            self.data('netdata-state-object', state);
        }
        return state;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Library functions

    // Load a script without jquery
    // This is used to load jquery - after it is loaded, we use jquery
    NETDATA._loadjQuery = function(callback) {
        if(typeof jQuery === 'undefined') {
            if(NETDATA.options.debug.main_loop === true)
                console.log('loading ' + NETDATA.jQuery);

            var script = document.createElement('script');
            script.type = 'text/javascript';
            script.async = true;
            script.src = NETDATA.jQuery;

            // script.onabort = onError;
            script.onerror = function() { NETDATA.error(101, NETDATA.jQuery); };
            if(typeof callback === "function") {
                script.onload = function () {
                    $ = jQuery;
                    return callback();
                };
            }

            var s = document.getElementsByTagName('script')[0];
            s.parentNode.insertBefore(script, s);
        }
        else if(typeof callback === "function") {
            $ = jQuery;
            return callback();
        }
    };

    NETDATA._loadCSS = function(filename) {
        // don't use jQuery here
        // styles are loaded before jQuery
        // to eliminate showing an unstyled page to the user

        var fileref = document.createElement("link");
        fileref.setAttribute("rel", "stylesheet");
        fileref.setAttribute("type", "text/css");
        fileref.setAttribute("href", filename);

        if (typeof fileref !== 'undefined')
            document.getElementsByTagName("head")[0].appendChild(fileref);
    };

    NETDATA.colorHex2Rgb = function(hex) {
        // Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
        var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
            hex = hex.replace(shorthandRegex, function(m, r, g, b) {
            return r + r + g + g + b + b;
        });

        var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
        return result ? {
            r: parseInt(result[1], 16),
            g: parseInt(result[2], 16),
            b: parseInt(result[3], 16)
        } : null;
    };

    NETDATA.colorLuminance = function(hex, lum) {
        // validate hex string
        hex = String(hex).replace(/[^0-9a-f]/gi, '');
        if (hex.length < 6)
            hex = hex[0]+hex[0]+hex[1]+hex[1]+hex[2]+hex[2];

        lum = lum || 0;

        // convert to decimal and change luminosity
        var rgb = "#", c, i;
        for (i = 0; i < 3; i++) {
            c = parseInt(hex.substr(i*2,2), 16);
            c = Math.round(Math.min(Math.max(0, c + (c * lum)), 255)).toString(16);
            rgb += ("00"+c).substr(c.length);
        }

        return rgb;
    };

    NETDATA.guid = function() {
        function s4() {
            return Math.floor((1 + Math.random()) * 0x10000)
                    .toString(16)
                    .substring(1);
            }

            return s4() + s4() + '-' + s4() + '-' + s4() + '-' + s4() + '-' + s4() + s4() + s4();
    };

    NETDATA.zeropad = function(x) {
        if(x > -10 && x < 10) return '0' + x.toString();
        else return x.toString();
    };

    // user function to signal us the DOM has been
    // updated.
    NETDATA.updatedDom = function() {
        NETDATA.options.updated_dom = true;
    };

    NETDATA.ready = function(callback) {
        NETDATA.options.pauseCallback = callback;
    };

    NETDATA.pause = function(callback) {
        if(typeof callback === 'function') {
            if (NETDATA.options.pause === true)
                return callback();
            else
                NETDATA.options.pauseCallback = callback;
        }
    };

    NETDATA.unpause = function() {
        NETDATA.options.pauseCallback = null;
        NETDATA.options.updated_dom = true;
        NETDATA.options.pause = false;
    };

    NETDATA.seconds4human = function (seconds, options) {
        var default_options = {
            now: 'now',
            space: ' ',
            negative_suffix: 'ago',
            day: 'day',
            days: 'days',
            hour: 'hour',
            hours: 'hours',
            minute: 'min',
            minutes: 'mins',
            second: 'sec',
            seconds: 'secs',
            and: 'and'
        };

        if(typeof options !== 'object')
            options = default_options;
        else {
            var x;
            for(x in default_options) {
                if(typeof options[x] !== 'string')
                    options[x] = default_options[x];
            }
        }

        if(typeof seconds === 'string')
            seconds = parseInt(seconds, 10);

        if(seconds === 0)
            return options.now;

        var suffix = '';
        if(seconds < 0) {
            seconds = -seconds;
            if(options.negative_suffix !== '') suffix = options.space + options.negative_suffix;
        }

        var days = Math.floor(seconds / 86400);
        seconds -= (days * 86400);

        var hours = Math.floor(seconds / 3600);
        seconds -= (hours * 3600);

        var minutes = Math.floor(seconds / 60);
        seconds -= (minutes * 60);

        var strings = [];

        if(days > 1) strings.push(days.toString() + options.space + options.days);
        else if(days === 1) strings.push(days.toString() + options.space + options.day);

        if(hours > 1) strings.push(hours.toString() + options.space + options.hours);
        else if(hours === 1) strings.push(hours.toString() + options.space + options.hour);

        if(minutes > 1) strings.push(minutes.toString() + options.space + options.minutes);
        else if(minutes === 1) strings.push(minutes.toString() + options.space + options.minute);

        if(seconds > 1) strings.push(Math.floor(seconds).toString() + options.space + options.seconds);
        else if(seconds === 1) strings.push(Math.floor(seconds).toString() + options.space + options.second);

        if(strings.length === 1)
            return strings.pop() + suffix;

        var last = strings.pop();
        return strings.join(", ") + " " + options.and + " " + last + suffix;
    };

    // ----------------------------------------------------------------------------------------------------------------

    // this is purely sequential charts refresher
    // it is meant to be autonomous
    NETDATA.chartRefresherNoParallel = function(index, callback) {
        if(NETDATA.options.debug.main_loop === true)
            console.log('NETDATA.chartRefresherNoParallel(' + index + ')');

        if(NETDATA.options.updated_dom === true) {
            // the dom has been updated
            // get the dom parts again
            NETDATA.parseDom(callback);
            return;
        }
        if(index >= NETDATA.options.targets.length) {
            if(NETDATA.options.debug.main_loop === true)
                console.log('waiting to restart main loop...');

            NETDATA.options.auto_refresher_fast_weight = 0;
            callback();
        }
        else {
            var state = NETDATA.options.targets[index];

            if(NETDATA.options.auto_refresher_fast_weight < NETDATA.options.current.fast_render_timeframe) {
                if(NETDATA.options.debug.main_loop === true)
                    console.log('fast rendering...');

                if(state.isVisible() === true)
                    NETDATA.timeout.set(function() {
                        state.autoRefresh(function () {
                            NETDATA.chartRefresherNoParallel(++index, callback);
                        });
                    }, 0);
                else
                    NETDATA.chartRefresherNoParallel(++index, callback);
            }
            else {
                if(NETDATA.options.debug.main_loop === true) console.log('waiting for next refresh...');
                NETDATA.options.auto_refresher_fast_weight = 0;

                NETDATA.timeout.set(function() {
                    state.autoRefresh(function() {
                        NETDATA.chartRefresherNoParallel(++index, callback);
                    });
                }, NETDATA.options.current.idle_between_charts);
            }
        }
    };

    NETDATA.chartRefresherWaitTime = function() {
        return NETDATA.options.current.idle_parallel_loops;
    };

    // the default refresher
    NETDATA.chartRefresherLastRun = 0;
    NETDATA.chartRefresherRunsAfterParseDom = 0;
    NETDATA.chartRefresherTimeoutId = undefined;

    NETDATA.chartRefresherReschedule = function() {
        if(NETDATA.options.current.async_on_scroll === true) {
            if(NETDATA.chartRefresherTimeoutId)
                NETDATA.timeout.clear(NETDATA.chartRefresherTimeoutId);
            NETDATA.chartRefresherTimeoutId = NETDATA.timeout.set(NETDATA.chartRefresher, NETDATA.options.current.onscroll_worker_duration_threshold);
            //console.log('chartRefresherReschedule()');
        }
    };

    NETDATA.chartRefresher = function() {
        // console.log('chartRefresher() begin ' + (Date.now() - NETDATA.chartRefresherLastRun).toString() + ' ms since last run');

        if(NETDATA.options.page_is_visible === false
            && NETDATA.options.current.stop_updates_when_focus_is_lost === true
            && NETDATA.chartRefresherLastRun > NETDATA.options.last_page_resize
            && NETDATA.chartRefresherLastRun > NETDATA.options.last_page_scroll
            && NETDATA.chartRefresherRunsAfterParseDom > 10
        ) {
            setTimeout(
                NETDATA.chartRefresher,
                NETDATA.options.current.idle_lost_focus
            );

            // console.log('chartRefresher() page without focus, will run in ' + NETDATA.options.current.idle_lost_focus.toString() + ' ms, ' + NETDATA.chartRefresherRunsAfterParseDom.toString());
            return;
        }
        NETDATA.chartRefresherRunsAfterParseDom++;

        var now = Date.now();
        NETDATA.chartRefresherLastRun = now;

        if( now < NETDATA.options.on_scroll_refresher_stop_until ) {
            NETDATA.chartRefresherTimeoutId = NETDATA.timeout.set(
                NETDATA.chartRefresher,
                NETDATA.chartRefresherWaitTime()
            );

            // console.log('chartRefresher() end1 will run in ' + NETDATA.chartRefresherWaitTime().toString() + ' ms');
            return;
        }

        if( now < NETDATA.options.auto_refresher_stop_until ) {
            NETDATA.chartRefresherTimeoutId = NETDATA.timeout.set(
                NETDATA.chartRefresher,
                NETDATA.chartRefresherWaitTime()
            );

            // console.log('chartRefresher() end2 will run in ' + NETDATA.chartRefresherWaitTime().toString() + ' ms');
            return;
        }

        if(NETDATA.options.pause === true) {
            // console.log('auto-refresher is paused');
            NETDATA.chartRefresherTimeoutId = NETDATA.timeout.set(
                NETDATA.chartRefresher,
                NETDATA.chartRefresherWaitTime()
            );

            // console.log('chartRefresher() end3 will run in ' + NETDATA.chartRefresherWaitTime().toString() + ' ms');
            return;
        }

        if(typeof NETDATA.options.pauseCallback === 'function') {
            // console.log('auto-refresher is calling pauseCallback');

            NETDATA.options.pause = true;
            NETDATA.options.pauseCallback();
            NETDATA.chartRefresher();

            // console.log('chartRefresher() end4 (nested)');
            return;
        }

        if(NETDATA.options.current.parallel_refresher === false) {
            // console.log('auto-refresher is calling chartRefresherNoParallel(0)');
            NETDATA.chartRefresherNoParallel(0, function() {
                NETDATA.chartRefresherTimeoutId = NETDATA.timeout.set(
                    NETDATA.chartRefresher,
                    NETDATA.options.current.idle_between_loops
                );
            });
            // console.log('chartRefresher() end5 (no parallel, nested)');
            return;
        }

        if(NETDATA.options.updated_dom === true) {
            // the dom has been updated
            // get the dom parts again
            // console.log('auto-refresher is calling parseDom()');
            NETDATA.parseDom(NETDATA.chartRefresher);
            // console.log('chartRefresher() end6 (parseDom)');
            return;
        }

        if(NETDATA.globalSelectionSync.active() === false) {
            var parallel = [];
            var targets = NETDATA.options.targets;
            var len = targets.length;
            var state;
            while(len--) {
                state = targets[len];
                if(state.isVisible() === false || state.running === true)
                    continue;

                if(state.library.initialized === false) {
                    if(state.library.enabled === true) {
                        state.library.initialize(NETDATA.chartRefresher);
                        //console.log('chartRefresher() end6 (library init)');
                        return;
                    }
                    else {
                        state.error('chart library "' + state.library_name + '" is not enabled.');
                    }
                }

                if(NETDATA.scrollUp === true)
                    parallel.unshift(state);
                else
                    parallel.push(state);
            }

            len = parallel.length;
            while (len--) {
                state = parallel[len];
                // console.log('auto-refresher executing in parallel for ' + parallel.length.toString() + ' charts');
                // this will execute the jobs in parallel

                if (state.running === false)
                    NETDATA.timeout.set(state.autoRefresh, 0);
            }
            //else {
            //    console.log('auto-refresher nothing to do');
            //}
        }

        // run the next refresh iteration
        NETDATA.chartRefresherTimeoutId = NETDATA.timeout.set(
            NETDATA.chartRefresher,
            NETDATA.chartRefresherWaitTime()
        );

        //console.log('chartRefresher() completed in ' + (Date.now() - now).toString() + ' ms');
    };

    NETDATA.parseDom = function(callback) {
        //console.log('parseDom()');

        NETDATA.options.last_page_scroll = Date.now();
        NETDATA.options.updated_dom = false;
        NETDATA.chartRefresherRunsAfterParseDom = 0;

        var targets = $('div[data-netdata]'); //.filter(':visible');

        if(NETDATA.options.debug.main_loop === true)
            console.log('DOM updated - there are ' + targets.length + ' charts on page.');

        NETDATA.options.targets = [];
        var len = targets.length;
        while(len--) {
            // the initialization will take care of sizing
            // and the "loading..." message
            NETDATA.options.targets.push(NETDATA.chartState(targets[len]));
        }

        if(NETDATA.globalChartUnderlay.isActive() === true)
            NETDATA.globalChartUnderlay.setup();
        else
            NETDATA.globalChartUnderlay.clear();

        if(typeof callback === 'function')
            return callback();
    };

    // this is the main function - where everything starts
    NETDATA.started = false;
    NETDATA.start = function() {
        // this should be called only once

        if(NETDATA.started === true) {
            console.log('netdata is already started');
            return;
        }

        NETDATA.started = true;
        NETDATA.options.page_is_visible = true;

        $(window).blur(function() {
            if(NETDATA.options.current.stop_updates_when_focus_is_lost === true) {
                NETDATA.options.page_is_visible = false;
                if(NETDATA.options.debug.focus === true)
                    console.log('Lost Focus!');
            }
        });

        $(window).focus(function() {
            if(NETDATA.options.current.stop_updates_when_focus_is_lost === true) {
                NETDATA.options.page_is_visible = true;
                if(NETDATA.options.debug.focus === true)
                    console.log('Focus restored!');
            }
        });

        if(typeof document.hasFocus === 'function' && !document.hasFocus()) {
            if(NETDATA.options.current.stop_updates_when_focus_is_lost === true) {
                NETDATA.options.page_is_visible = false;
                if(NETDATA.options.debug.focus === true)
                    console.log('Document has no focus!');
            }
        }

        // bootstrap tab switching
        $('a[data-toggle="tab"]').on('shown.bs.tab', NETDATA.onscroll);

        // bootstrap modal switching
        var $modal = $('.modal');
        $modal.on('hidden.bs.modal', NETDATA.onscroll);
        $modal.on('shown.bs.modal', NETDATA.onscroll);

        // bootstrap collapse switching
        var $collapse = $('.collapse');
        $collapse.on('hidden.bs.collapse', NETDATA.onscroll);
        $collapse.on('shown.bs.collapse', NETDATA.onscroll);

        NETDATA.parseDom(NETDATA.chartRefresher);

        // Alarms initialization
        setTimeout(NETDATA.alarms.init, 1000);

        // Registry initialization
        setTimeout(NETDATA.registry.init, netdataRegistryAfterMs);

        if(typeof netdataCallback === 'function')
            netdataCallback();
    };

    NETDATA.globalReset = function() {
        NETDATA.globalSelectionSync.globalReset();
        NETDATA.globalPanAndZoom.globalReset();
        NETDATA.chartRegistry.globalReset();
        NETDATA.commonMin.globalReset();
        NETDATA.commonMax.globalReset();
        NETDATA.unitsConversion.globalReset();
        NETDATA.options.targets = null;
        NETDATA.parseDom();
        NETDATA.unpause();
    };

    // ----------------------------------------------------------------------------------------------------------------
    // peity

    NETDATA.peityInitialize = function(callback) {
        if(typeof netdataNoPeitys === 'undefined' || !netdataNoPeitys) {
            $.ajax({
                url: NETDATA.peity_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
            .done(function() {
                NETDATA.registerChartLibrary('peity', NETDATA.peity_js);
            })
            .fail(function() {
                NETDATA.chartLibraries.peity.enabled = false;
                NETDATA.error(100, NETDATA.peity_js);
            })
            .always(function() {
                if(typeof callback === "function")
                    return callback();
            });
        }
        else {
            NETDATA.chartLibraries.peity.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.peityChartUpdate = function(state, data) {
        state.peity_instance.innerHTML = data.result;

        if(state.peity_options.stroke !== state.chartCustomColors()[0]) {
            state.peity_options.stroke = state.chartCustomColors()[0];
            if(state.chart.chart_type === 'line')
                state.peity_options.fill = NETDATA.themes.current.background;
            else
                state.peity_options.fill = NETDATA.colorLuminance(state.chartCustomColors()[0], NETDATA.chartDefaults.fill_luminance);
        }

        $(state.peity_instance).peity('line', state.peity_options);
        return true;
    };

    NETDATA.peityChartCreate = function(state, data) {
        state.peity_instance = document.createElement('div');
        state.element_chart.appendChild(state.peity_instance);

        state.peity_options = {
            stroke: NETDATA.themes.current.foreground,
            strokeWidth: NETDATA.dataAttribute(state.element, 'peity-strokewidth', 1),
            width: state.chartWidth(),
            height: state.chartHeight(),
            fill: NETDATA.themes.current.foreground
        };

        NETDATA.peityChartUpdate(state, data);
        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // sparkline

    NETDATA.sparklineInitialize = function(callback) {
        if(typeof netdataNoSparklines === 'undefined' || !netdataNoSparklines) {
            $.ajax({
                url: NETDATA.sparkline_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
            .done(function() {
                NETDATA.registerChartLibrary('sparkline', NETDATA.sparkline_js);
            })
            .fail(function() {
                NETDATA.chartLibraries.sparkline.enabled = false;
                NETDATA.error(100, NETDATA.sparkline_js);
            })
            .always(function() {
                if(typeof callback === "function")
                    return callback();
            });
        }
        else {
            NETDATA.chartLibraries.sparkline.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.sparklineChartUpdate = function(state, data) {
        state.sparkline_options.width = state.chartWidth();
        state.sparkline_options.height = state.chartHeight();

        $(state.element_chart).sparkline(data.result, state.sparkline_options);
        return true;
    };

    NETDATA.sparklineChartCreate = function(state, data) {
        var type = NETDATA.dataAttribute(state.element, 'sparkline-type', 'line');
        var lineColor = NETDATA.dataAttribute(state.element, 'sparkline-linecolor', state.chartCustomColors()[0]);
        var fillColor = NETDATA.dataAttribute(state.element, 'sparkline-fillcolor', ((state.chart.chart_type === 'line')?NETDATA.themes.current.background:NETDATA.colorLuminance(lineColor, NETDATA.chartDefaults.fill_luminance)));
        var chartRangeMin = NETDATA.dataAttribute(state.element, 'sparkline-chartrangemin', undefined);
        var chartRangeMax = NETDATA.dataAttribute(state.element, 'sparkline-chartrangemax', undefined);
        var composite = NETDATA.dataAttribute(state.element, 'sparkline-composite', undefined);
        var enableTagOptions = NETDATA.dataAttribute(state.element, 'sparkline-enabletagoptions', undefined);
        var tagOptionPrefix = NETDATA.dataAttribute(state.element, 'sparkline-tagoptionprefix', undefined);
        var tagValuesAttribute = NETDATA.dataAttribute(state.element, 'sparkline-tagvaluesattribute', undefined);
        var disableHiddenCheck = NETDATA.dataAttribute(state.element, 'sparkline-disablehiddencheck', undefined);
        var defaultPixelsPerValue = NETDATA.dataAttribute(state.element, 'sparkline-defaultpixelspervalue', undefined);
        var spotColor = NETDATA.dataAttribute(state.element, 'sparkline-spotcolor', undefined);
        var minSpotColor = NETDATA.dataAttribute(state.element, 'sparkline-minspotcolor', undefined);
        var maxSpotColor = NETDATA.dataAttribute(state.element, 'sparkline-maxspotcolor', undefined);
        var spotRadius = NETDATA.dataAttribute(state.element, 'sparkline-spotradius', undefined);
        var valueSpots = NETDATA.dataAttribute(state.element, 'sparkline-valuespots', undefined);
        var highlightSpotColor = NETDATA.dataAttribute(state.element, 'sparkline-highlightspotcolor', undefined);
        var highlightLineColor = NETDATA.dataAttribute(state.element, 'sparkline-highlightlinecolor', undefined);
        var lineWidth = NETDATA.dataAttribute(state.element, 'sparkline-linewidth', undefined);
        var normalRangeMin = NETDATA.dataAttribute(state.element, 'sparkline-normalrangemin', undefined);
        var normalRangeMax = NETDATA.dataAttribute(state.element, 'sparkline-normalrangemax', undefined);
        var drawNormalOnTop = NETDATA.dataAttribute(state.element, 'sparkline-drawnormalontop', undefined);
        var xvalues = NETDATA.dataAttribute(state.element, 'sparkline-xvalues', undefined);
        var chartRangeClip = NETDATA.dataAttribute(state.element, 'sparkline-chartrangeclip', undefined);
        var chartRangeMinX = NETDATA.dataAttribute(state.element, 'sparkline-chartrangeminx', undefined);
        var chartRangeMaxX = NETDATA.dataAttribute(state.element, 'sparkline-chartrangemaxx', undefined);
        var disableInteraction = NETDATA.dataAttributeBoolean(state.element, 'sparkline-disableinteraction', false);
        var disableTooltips = NETDATA.dataAttributeBoolean(state.element, 'sparkline-disabletooltips', false);
        var disableHighlight = NETDATA.dataAttributeBoolean(state.element, 'sparkline-disablehighlight', false);
        var highlightLighten = NETDATA.dataAttribute(state.element, 'sparkline-highlightlighten', 1.4);
        var highlightColor = NETDATA.dataAttribute(state.element, 'sparkline-highlightcolor', undefined);
        var tooltipContainer = NETDATA.dataAttribute(state.element, 'sparkline-tooltipcontainer', undefined);
        var tooltipClassname = NETDATA.dataAttribute(state.element, 'sparkline-tooltipclassname', undefined);
        var tooltipFormat = NETDATA.dataAttribute(state.element, 'sparkline-tooltipformat', undefined);
        var tooltipPrefix = NETDATA.dataAttribute(state.element, 'sparkline-tooltipprefix', undefined);
        var tooltipSuffix = NETDATA.dataAttribute(state.element, 'sparkline-tooltipsuffix', ' ' + state.units_current);
        var tooltipSkipNull = NETDATA.dataAttributeBoolean(state.element, 'sparkline-tooltipskipnull', true);
        var tooltipValueLookups = NETDATA.dataAttribute(state.element, 'sparkline-tooltipvaluelookups', undefined);
        var tooltipFormatFieldlist = NETDATA.dataAttribute(state.element, 'sparkline-tooltipformatfieldlist', undefined);
        var tooltipFormatFieldlistKey = NETDATA.dataAttribute(state.element, 'sparkline-tooltipformatfieldlistkey', undefined);
        var numberFormatter = NETDATA.dataAttribute(state.element, 'sparkline-numberformatter', function(n){ return n.toFixed(2); });
        var numberDigitGroupSep = NETDATA.dataAttribute(state.element, 'sparkline-numberdigitgroupsep', undefined);
        var numberDecimalMark = NETDATA.dataAttribute(state.element, 'sparkline-numberdecimalmark', undefined);
        var numberDigitGroupCount = NETDATA.dataAttribute(state.element, 'sparkline-numberdigitgroupcount', undefined);
        var animatedZooms = NETDATA.dataAttributeBoolean(state.element, 'sparkline-animatedzooms', false);

        if(spotColor === 'disable') spotColor='';
        if(minSpotColor === 'disable') minSpotColor='';
        if(maxSpotColor === 'disable') maxSpotColor='';

        // state.log('sparkline type ' + type + ', lineColor: ' + lineColor + ', fillColor: ' + fillColor);

        state.sparkline_options = {
            type: type,
            lineColor: lineColor,
            fillColor: fillColor,
            chartRangeMin: chartRangeMin,
            chartRangeMax: chartRangeMax,
            composite: composite,
            enableTagOptions: enableTagOptions,
            tagOptionPrefix: tagOptionPrefix,
            tagValuesAttribute: tagValuesAttribute,
            disableHiddenCheck: disableHiddenCheck,
            defaultPixelsPerValue: defaultPixelsPerValue,
            spotColor: spotColor,
            minSpotColor: minSpotColor,
            maxSpotColor: maxSpotColor,
            spotRadius: spotRadius,
            valueSpots: valueSpots,
            highlightSpotColor: highlightSpotColor,
            highlightLineColor: highlightLineColor,
            lineWidth: lineWidth,
            normalRangeMin: normalRangeMin,
            normalRangeMax: normalRangeMax,
            drawNormalOnTop: drawNormalOnTop,
            xvalues: xvalues,
            chartRangeClip: chartRangeClip,
            chartRangeMinX: chartRangeMinX,
            chartRangeMaxX: chartRangeMaxX,
            disableInteraction: disableInteraction,
            disableTooltips: disableTooltips,
            disableHighlight: disableHighlight,
            highlightLighten: highlightLighten,
            highlightColor: highlightColor,
            tooltipContainer: tooltipContainer,
            tooltipClassname: tooltipClassname,
            tooltipChartTitle: state.title,
            tooltipFormat: tooltipFormat,
            tooltipPrefix: tooltipPrefix,
            tooltipSuffix: tooltipSuffix,
            tooltipSkipNull: tooltipSkipNull,
            tooltipValueLookups: tooltipValueLookups,
            tooltipFormatFieldlist: tooltipFormatFieldlist,
            tooltipFormatFieldlistKey: tooltipFormatFieldlistKey,
            numberFormatter: numberFormatter,
            numberDigitGroupSep: numberDigitGroupSep,
            numberDecimalMark: numberDecimalMark,
            numberDigitGroupCount: numberDigitGroupCount,
            animatedZooms: animatedZooms,
            width: state.chartWidth(),
            height: state.chartHeight()
        };

        $(state.element_chart).sparkline(data.result, state.sparkline_options);

        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // dygraph

    NETDATA.dygraph = {
        smooth: false
    };

    NETDATA.dygraphToolboxPanAndZoom = function(state, after, before) {
        if(after < state.netdata_first)
            after = state.netdata_first;

        if(before > state.netdata_last)
            before = state.netdata_last;

        state.setMode('zoom');
        NETDATA.globalSelectionSync.stop();
        NETDATA.globalSelectionSync.delay();
        state.tmp.dygraph_user_action = true;
        state.tmp.dygraph_force_zoom = true;
        // state.log('toolboxPanAndZoom');
        state.updateChartPanOrZoom(after, before);
        NETDATA.globalPanAndZoom.setMaster(state, after, before);
    };

    NETDATA.dygraphSetSelection = function(state, t) {
        if(typeof state.tmp.dygraph_instance !== 'undefined') {
            var r = state.calculateRowForTime(t);
            if(r !== -1) {
                state.tmp.dygraph_instance.setSelection(r);
                return true;
            }
            else {
                state.tmp.dygraph_instance.clearSelection();
                state.legendShowUndefined();
            }
        }

        return false;
    };

    NETDATA.dygraphClearSelection = function(state) {
        if(typeof state.tmp.dygraph_instance !== 'undefined') {
            state.tmp.dygraph_instance.clearSelection();
        }
        return true;
    };

    NETDATA.dygraphSmoothInitialize = function(callback) {
        $.ajax({
            url: NETDATA.dygraph_smooth_js,
            cache: true,
            dataType: "script",
            xhrFields: { withCredentials: true } // required for the cookie
        })
        .done(function() {
            NETDATA.dygraph.smooth = true;
            smoothPlotter.smoothing = 0.3;
        })
        .fail(function() {
            NETDATA.dygraph.smooth = false;
        })
        .always(function() {
            if(typeof callback === "function")
                return callback();
        });
    };

    NETDATA.dygraphInitialize = function(callback) {
        if(typeof netdataNoDygraphs === 'undefined' || !netdataNoDygraphs) {
            $.ajax({
                url: NETDATA.dygraph_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
            .done(function() {
                NETDATA.registerChartLibrary('dygraph', NETDATA.dygraph_js);
            })
            .fail(function() {
                NETDATA.chartLibraries.dygraph.enabled = false;
                NETDATA.error(100, NETDATA.dygraph_js);
            })
            .always(function() {
                if(NETDATA.chartLibraries.dygraph.enabled === true && NETDATA.options.current.smooth_plot === true)
                    NETDATA.dygraphSmoothInitialize(callback);
                else if(typeof callback === "function")
                    return callback();
            });
        }
        else {
            NETDATA.chartLibraries.dygraph.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.dygraphChartUpdate = function(state, data) {
        var dygraph = state.tmp.dygraph_instance;

        if(typeof dygraph === 'undefined')
            return NETDATA.dygraphChartCreate(state, data);

        // when the chart is not visible, and hidden
        // if there is a window resize, dygraph detects
        // its element size as 0x0.
        // this will make it re-appear properly

        if(state.tm.last_unhidden > state.tmp.dygraph_last_rendered)
            dygraph.resize();

        var options = {
                file: data.result.data,
                colors: state.chartColors(),
                labels: data.result.labels,
                labelsDivWidth: state.chartWidth() - 70,
                visibility: state.dimensions_visibility.selected2BooleanArray(state.data.dimension_names)
        };

        if(!NETDATA.chartLibraries.dygraph.isSparkline(state)) {
            options.ylabel = state.units_current; // (state.units_desired === 'auto')?"":state.units_current;
        }

        if(state.tmp.dygraph_force_zoom === true) {
            if(NETDATA.options.debug.dygraph === true || state.debug === true)
                state.log('dygraphChartUpdate() forced zoom update');

            options.dateWindow = (state.requested_padding !== null)?[ state.view_after, state.view_before ]:null;
            options.isZoomedIgnoreProgrammaticZoom = true;
            state.tmp.dygraph_force_zoom = false;
        }
        else if(state.current.name !== 'auto') {
            if(NETDATA.options.debug.dygraph === true || state.debug === true)
                state.log('dygraphChartUpdate() loose update');
        }
        else {
            if(NETDATA.options.debug.dygraph === true || state.debug === true)
                state.log('dygraphChartUpdate() strict update');

            options.dateWindow = (state.requested_padding !== null)?[ state.view_after, state.view_before ]:null;
            options.isZoomedIgnoreProgrammaticZoom = true;
        }

        options.valueRange = state.tmp.dygraph_options.valueRange;

        var oldMax = null, oldMin = null;
        if (state.tmp.__commonMin !== null) {
            state.data.min = state.tmp.dygraph_instance.axes_[0].extremeRange[0];
            oldMin = options.valueRange[0] = NETDATA.commonMin.get(state);
        }
        if (state.tmp.__commonMax !== null) {
            state.data.max = state.tmp.dygraph_instance.axes_[0].extremeRange[1];
            oldMax = options.valueRange[1] = NETDATA.commonMax.get(state);
        }

        if(state.tmp.dygraph_smooth_eligible === true) {
            if((NETDATA.options.current.smooth_plot === true && state.tmp.dygraph_options.plotter !== smoothPlotter)
                || (NETDATA.options.current.smooth_plot === false && state.tmp.dygraph_options.plotter === smoothPlotter)) {
                NETDATA.dygraphChartCreate(state, data);
                return;
            }
        }

        if(netdataSnapshotData !== null && NETDATA.globalPanAndZoom.isActive() === true && NETDATA.globalPanAndZoom.isMaster(state) === false) {
            // pan and zoom on snapshots
            options.dateWindow = [ NETDATA.globalPanAndZoom.force_after_ms, NETDATA.globalPanAndZoom.force_before_ms ];
            options.isZoomedIgnoreProgrammaticZoom = true;
        }

        dygraph.updateOptions(options);

        var redraw = false;
        if(oldMin !== null && oldMin > state.tmp.dygraph_instance.axes_[0].extremeRange[0]) {
            state.data.min = state.tmp.dygraph_instance.axes_[0].extremeRange[0];
            options.valueRange[0] = NETDATA.commonMin.get(state);
            redraw = true;
        }
        if(oldMax !== null && oldMax < state.tmp.dygraph_instance.axes_[0].extremeRange[1]) {
            state.data.max = state.tmp.dygraph_instance.axes_[0].extremeRange[1];
            options.valueRange[1] = NETDATA.commonMax.get(state);
            redraw = true;
        }

        if(redraw === true) {
            // state.log('forcing redraw to adapt to common- min/max');
            dygraph.updateOptions(options);
        }

        state.tmp.dygraph_last_rendered = Date.now();
        return true;
    };

    NETDATA.dygraphChartCreate = function(state, data) {
        if(NETDATA.options.debug.dygraph === true || state.debug === true)
            state.log('dygraphChartCreate()');

        var chart_type = NETDATA.dataAttribute(state.element, 'dygraph-type', state.chart.chart_type);
        if(chart_type === 'stacked' && data.dimensions === 1) chart_type = 'area';

        var highlightCircleSize = (NETDATA.chartLibraries.dygraph.isSparkline(state) === true)?3:4;

        var smooth = (NETDATA.dygraph.smooth === true)
            ?(NETDATA.dataAttributeBoolean(state.element, 'dygraph-smooth', (chart_type === 'line' && NETDATA.chartLibraries.dygraph.isSparkline(state) === false)))
            :false;

        state.tmp.dygraph_options = {
            colors:                 NETDATA.dataAttribute(state.element, 'dygraph-colors', state.chartColors()),

            // leave a few pixels empty on the right of the chart
            rightGap:               NETDATA.dataAttribute(state.element, 'dygraph-rightgap', 5),
            showRangeSelector:      NETDATA.dataAttributeBoolean(state.element, 'dygraph-showrangeselector', false),
            showRoller:             NETDATA.dataAttributeBoolean(state.element, 'dygraph-showroller', false),
            title:                  NETDATA.dataAttribute(state.element, 'dygraph-title', state.title),
            titleHeight:            NETDATA.dataAttribute(state.element, 'dygraph-titleheight', 19),
            legend:                 NETDATA.dataAttribute(state.element, 'dygraph-legend', 'always'), // we need this to get selection events
            labels:                 data.result.labels,
            labelsDiv:              NETDATA.dataAttribute(state.element, 'dygraph-labelsdiv', state.element_legend_childs.hidden),
            labelsDivStyles:        NETDATA.dataAttribute(state.element, 'dygraph-labelsdivstyles', { 'fontSize':'1px' }),
            labelsDivWidth:         NETDATA.dataAttribute(state.element, 'dygraph-labelsdivwidth', state.chartWidth() - 70),
            labelsSeparateLines:    NETDATA.dataAttributeBoolean(state.element, 'dygraph-labelsseparatelines', true),
            labelsShowZeroValues:   NETDATA.dataAttributeBoolean(state.element, 'dygraph-labelsshowzerovalues', true),
            labelsKMB:              false,
            labelsKMG2:             false,
            showLabelsOnHighlight:  NETDATA.dataAttributeBoolean(state.element, 'dygraph-showlabelsonhighlight', true),
            hideOverlayOnMouseOut:  NETDATA.dataAttributeBoolean(state.element, 'dygraph-hideoverlayonmouseout', true),
            includeZero:            NETDATA.dataAttribute(state.element, 'dygraph-includezero', (chart_type === 'stacked')),
            xRangePad:              NETDATA.dataAttribute(state.element, 'dygraph-xrangepad', 0),
            yRangePad:              NETDATA.dataAttribute(state.element, 'dygraph-yrangepad', 1),
            valueRange:             NETDATA.dataAttribute(state.element, 'dygraph-valuerange', [ null, null ]),
            ylabel:                 state.units_current, // (state.units_desired === 'auto')?"":state.units_current,
            yLabelWidth:            NETDATA.dataAttribute(state.element, 'dygraph-ylabelwidth', 12),

                                    // the function to plot the chart
            plotter:                null,

                                    // The width of the lines connecting data points.
                                    // This can be used to increase the contrast or some graphs.
            strokeWidth:            NETDATA.dataAttribute(state.element, 'dygraph-strokewidth', ((chart_type === 'stacked')?0.1:((smooth === true)?1.5:0.7))),
            strokePattern:          NETDATA.dataAttribute(state.element, 'dygraph-strokepattern', undefined),

                                    // The size of the dot to draw on each point in pixels (see drawPoints).
                                    // A dot is always drawn when a point is "isolated",
                                    // i.e. there is a missing point on either side of it.
                                    // This also controls the size of those dots.
            drawPoints:             NETDATA.dataAttributeBoolean(state.element, 'dygraph-drawpoints', false),

                                    // Draw points at the edges of gaps in the data.
                                    // This improves visibility of small data segments or other data irregularities.
            drawGapEdgePoints:      NETDATA.dataAttributeBoolean(state.element, 'dygraph-drawgapedgepoints', true),
            connectSeparatedPoints: NETDATA.dataAttributeBoolean(state.element, 'dygraph-connectseparatedpoints', false),
            pointSize:              NETDATA.dataAttribute(state.element, 'dygraph-pointsize', 1),

                                    // enabling this makes the chart with little square lines
            stepPlot:               NETDATA.dataAttributeBoolean(state.element, 'dygraph-stepplot', false),

                                    // Draw a border around graph lines to make crossing lines more easily
                                    // distinguishable. Useful for graphs with many lines.
            strokeBorderColor:      NETDATA.dataAttribute(state.element, 'dygraph-strokebordercolor', NETDATA.themes.current.background),
            strokeBorderWidth:      NETDATA.dataAttribute(state.element, 'dygraph-strokeborderwidth', (chart_type === 'stacked')?0.0:0.0),
            fillGraph:              NETDATA.dataAttribute(state.element, 'dygraph-fillgraph', (chart_type === 'area' || chart_type === 'stacked')),
            fillAlpha:              NETDATA.dataAttribute(state.element, 'dygraph-fillalpha',
                                    ((chart_type === 'stacked')
                                        ?NETDATA.options.current.color_fill_opacity_stacked
                                        :NETDATA.options.current.color_fill_opacity_area)
                                    ),
            stackedGraph:           NETDATA.dataAttribute(state.element, 'dygraph-stackedgraph', (chart_type === 'stacked')),
            stackedGraphNaNFill:    NETDATA.dataAttribute(state.element, 'dygraph-stackedgraphnanfill', 'none'),
            drawAxis:               NETDATA.dataAttributeBoolean(state.element, 'dygraph-drawaxis', true),
            axisLabelFontSize:      NETDATA.dataAttribute(state.element, 'dygraph-axislabelfontsize', 10),
            axisLineColor:          NETDATA.dataAttribute(state.element, 'dygraph-axislinecolor', NETDATA.themes.current.axis),
            axisLineWidth:          NETDATA.dataAttribute(state.element, 'dygraph-axislinewidth', 1.0),
            drawGrid:               NETDATA.dataAttributeBoolean(state.element, 'dygraph-drawgrid', true),
            gridLinePattern:        NETDATA.dataAttribute(state.element, 'dygraph-gridlinepattern', null),
            gridLineWidth:          NETDATA.dataAttribute(state.element, 'dygraph-gridlinewidth', 1.0),
            gridLineColor:          NETDATA.dataAttribute(state.element, 'dygraph-gridlinecolor', NETDATA.themes.current.grid),
            maxNumberWidth:         NETDATA.dataAttribute(state.element, 'dygraph-maxnumberwidth', 8),
            sigFigs:                NETDATA.dataAttribute(state.element, 'dygraph-sigfigs', null),
            digitsAfterDecimal:     NETDATA.dataAttribute(state.element, 'dygraph-digitsafterdecimal', 2),
            valueFormatter:         NETDATA.dataAttribute(state.element, 'dygraph-valueformatter', undefined),
            highlightCircleSize:    NETDATA.dataAttribute(state.element, 'dygraph-highlightcirclesize', highlightCircleSize),
            highlightSeriesOpts:    NETDATA.dataAttribute(state.element, 'dygraph-highlightseriesopts', null), // TOO SLOW: { strokeWidth: 1.5 },
            highlightSeriesBackgroundAlpha: NETDATA.dataAttribute(state.element, 'dygraph-highlightseriesbackgroundalpha', null), // TOO SLOW: (chart_type === 'stacked')?0.7:0.5,
            pointClickCallback:     NETDATA.dataAttribute(state.element, 'dygraph-pointclickcallback', undefined),
            visibility:             state.dimensions_visibility.selected2BooleanArray(state.data.dimension_names),

            axes: {
                x: {
                    pixelsPerLabel: 50,
                    ticker: Dygraph.dateTicker,
                    axisLabelFormatter: function (d, gran) {
                        void(gran);
                        return NETDATA.dateTime.xAxisTimeString(d);
                    }
                },
                y: {
                    pixelsPerLabel: 15,
                    axisLabelFormatter: function (y) {

                        // unfortunately, we have to call this every single time
                        state.legendFormatValueDecimalsFromMinMax(
                            this.axes_[0].extremeRange[0],
                            this.axes_[0].extremeRange[1]
                        );

                        var old_units = this.user_attrs_.ylabel;
                        var v = state.legendFormatValue(y);
                        var new_units = state.units_current;

                        if(state.units_desired === 'auto' && typeof old_units !== 'undefined' && new_units !== old_units && !NETDATA.chartLibraries.dygraph.isSparkline(state)) {
                            // console.log(this);
                            // state.log('units discrepancy: old = ' + old_units + ', new = ' + new_units);
                            var len = this.plugins_.length;
                            while(len--) {
                                // console.log(this.plugins_[len]);
                                if(typeof this.plugins_[len].plugin.ylabel_div_ !== 'undefined'
                                    && this.plugins_[len].plugin.ylabel_div_ !== null
                                    && typeof this.plugins_[len].plugin.ylabel_div_.children !== 'undefined'
                                    && this.plugins_[len].plugin.ylabel_div_.children !== null
                                    && typeof this.plugins_[len].plugin.ylabel_div_.children[0].children !== 'undefined'
                                    && this.plugins_[len].plugin.ylabel_div_.children[0].children !== null
                                ) {
                                    this.plugins_[len].plugin.ylabel_div_.children[0].children[0].innerHTML = new_units;
                                    this.user_attrs_.ylabel = new_units;
                                    break;
                                }
                            }

                            if(len < 0)
                                state.log('units discrepancy, but cannot find dygraphs div to change: old = ' + old_units + ', new = ' + new_units);
                        }

                        return v;
                    }
                }
            },
            legendFormatter: function(data) {
                if(state.tmp.dygraph_mouse_down === true)
                    return;

                var elements = state.element_legend_childs;

                // if the hidden div is not there
                // we are not managing the legend
                if(elements.hidden === null) return;

                if (typeof data.x !== 'undefined') {
                    state.legendSetDate(data.x);
                    var i = data.series.length;
                    while(i--) {
                        var series = data.series[i];
                        if(series.isVisible === true)
                            state.legendSetLabelValue(series.label, series.y);
                        else
                            state.legendSetLabelValue(series.label, null);
                    }
                }

                return '';
            },
            drawCallback: function(dygraph, is_initial) {

                // the user has panned the chart and this is called to re-draw the chart
                // 1. refresh this chart by adding data to it
                // 2. notify all the other charts about the update they need

                // to prevent an infinite loop (feedback), we use
                //     state.tmp.dygraph_user_action
                // - when true, this is initiated by a user
                // - when false, this is feedback

                if(state.current.name !== 'auto' && state.tmp.dygraph_user_action === true) {
                    state.tmp.dygraph_user_action = false;

                    var x_range = dygraph.xAxisRange();
                    var after = Math.round(x_range[0]);
                    var before = Math.round(x_range[1]);

                    if(NETDATA.options.debug.dygraph === true)
                        state.log('dygraphDrawCallback(dygraph, ' + is_initial + '): mode ' + state.current.name + ' ' + (after / 1000).toString() + ' - ' + (before / 1000).toString());
                        //console.log(state);

                    if(before <= state.netdata_last && after >= state.netdata_first)
                        // update only when we are within the data limits
                        state.updateChartPanOrZoom(after, before);
                }
            },
            zoomCallback: function(minDate, maxDate, yRanges) {

                // the user has selected a range on the chart
                // 1. refresh this chart by adding data to it
                // 2. notify all the other charts about the update they need

                void(yRanges);

                if(NETDATA.options.debug.dygraph === true)
                    state.log('dygraphZoomCallback(): ' + state.current.name);

                NETDATA.globalSelectionSync.stop();
                NETDATA.globalSelectionSync.delay();
                state.setMode('zoom');

                // refresh it to the greatest possible zoom level
                state.tmp.dygraph_user_action = true;
                state.tmp.dygraph_force_zoom = true;
                state.updateChartPanOrZoom(minDate, maxDate);
            },
            highlightCallback: function(event, x, points, row, seriesName) {
                void(seriesName);

                state.pauseChart();

                // there is a bug in dygraph when the chart is zoomed enough
                // the time it thinks is selected is wrong
                // here we calculate the time t based on the row number selected
                // which is ok
                // var t = state.data_after + row * state.data_update_every;
                // console.log('row = ' + row + ', x = ' + x + ', t = ' + t + ' ' + ((t === x)?'SAME':(Math.abs(x-t)<=state.data_update_every)?'SIMILAR':'DIFFERENT') + ', rows in db: ' + state.data_points + ' visible(x) = ' + state.timeIsVisible(x) + ' visible(t) = ' + state.timeIsVisible(t) + ' r(x) = ' + state.calculateRowForTime(x) + ' r(t) = ' + state.calculateRowForTime(t) + ' range: ' + state.data_after + ' - ' + state.data_before + ' real: ' + state.data.after + ' - ' + state.data.before + ' every: ' + state.data_update_every);

                if(state.tmp.dygraph_mouse_down !== true)
                    NETDATA.globalSelectionSync.sync(state, x);

                // fix legend zIndex using the internal structures of dygraph legend module
                // this works, but it is a hack!
                // state.tmp.dygraph_instance.plugins_[0].plugin.legend_div_.style.zIndex = 10000;
            },
            unhighlightCallback: function(event) {
                void(event);

                if(state.tmp.dygraph_mouse_down === true)
                    return;

                if(NETDATA.options.debug.dygraph === true || state.debug === true)
                    state.log('dygraphUnhighlightCallback()');

                state.unpauseChart();
                NETDATA.globalSelectionSync.stop();
            },
            underlayCallback: function(canvas, area, g) {

                // the chart is about to be drawn
                // this function renders global highlighted time-frame

                if(NETDATA.globalChartUnderlay.isActive()) {
                    var after = NETDATA.globalChartUnderlay.after;
                    var before = NETDATA.globalChartUnderlay.before;

                    if(after < state.view_after)
                        after = state.view_after;

                    if(before > state.view_before)
                        before = state.view_before;

                    if(after < before) {
                        var bottom_left = g.toDomCoords(after, -20);
                        var top_right = g.toDomCoords(before, +20);

                        var left = bottom_left[0];
                        var right = top_right[0];

                        canvas.fillStyle = NETDATA.themes.current.highlight;
                        canvas.fillRect(left, area.y, right - left, area.h);
                    }
                }
            },
            interactionModel : {
                mousedown: function(event, dygraph, context) {
                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.mousedown()');

                    state.tmp.dygraph_user_action = true;

                    if(NETDATA.options.debug.dygraph === true)
                        state.log('dygraphMouseDown()');

                    // Right-click should not initiate anything.
                    if(event.button && event.button === 2) return;

                    NETDATA.globalSelectionSync.stop();
                    NETDATA.globalSelectionSync.delay();

                    state.tmp.dygraph_mouse_down = true;
                    context.initializeMouseDown(event, dygraph, context);

                    //console.log(event);
                    if(event.button && event.button === 1) {
                        if (event.shiftKey) {
                            //console.log('middle mouse button dragging (PAN)');

                            state.setMode('pan');
                            // NETDATA.globalSelectionSync.delay();
                            state.tmp.dygraph_highlight_after = null;
                            Dygraph.startPan(event, dygraph, context);
                        }
                        else if(event.altKey || event.ctrlKey || event.metaKey) {
                            //console.log('middle mouse button highlight');

                            if (!(event.offsetX && event.offsetY)) {
                                event.offsetX = event.layerX - event.target.offsetLeft;
                                event.offsetY = event.layerY - event.target.offsetTop;
                            }
                            state.tmp.dygraph_highlight_after = dygraph.toDataXCoord(event.offsetX);
                            Dygraph.startZoom(event, dygraph, context);
                        }
                        else {
                            //console.log('middle mouse button selection for zoom (ZOOM)');

                            state.setMode('zoom');
                            // NETDATA.globalSelectionSync.delay();
                            state.tmp.dygraph_highlight_after = null;
                            Dygraph.startZoom(event, dygraph, context);
                        }
                    }
                    else {
                        if (event.shiftKey) {
                            //console.log('left mouse button selection for zoom (ZOOM)');

                            state.setMode('zoom');
                            // NETDATA.globalSelectionSync.delay();
                            state.tmp.dygraph_highlight_after = null;
                            Dygraph.startZoom(event, dygraph, context);
                        }
                        else if(event.altKey || event.ctrlKey || event.metaKey) {
                            //console.log('left mouse button highlight');

                            if (!(event.offsetX && event.offsetY)) {
                                event.offsetX = event.layerX - event.target.offsetLeft;
                                event.offsetY = event.layerY - event.target.offsetTop;
                            }
                            state.tmp.dygraph_highlight_after = dygraph.toDataXCoord(event.offsetX);
                            Dygraph.startZoom(event, dygraph, context);
                        }
                        else {
                            //console.log('left mouse button dragging (PAN)');

                            state.setMode('pan');
                            // NETDATA.globalSelectionSync.delay();
                            state.tmp.dygraph_highlight_after = null;
                            Dygraph.startPan(event, dygraph, context);
                        }
                    }
                },
                mousemove: function(event, dygraph, context) {
                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.mousemove()');

                    if(state.tmp.dygraph_highlight_after !== null) {
                        //console.log('highlight selection...');

                        NETDATA.globalSelectionSync.stop();
                        NETDATA.globalSelectionSync.delay();

                        state.tmp.dygraph_user_action = true;
                        Dygraph.moveZoom(event, dygraph, context);
                        event.preventDefault();
                    }
                    else if(context.isPanning) {
                        //console.log('panning...');

                        NETDATA.globalSelectionSync.stop();
                        NETDATA.globalSelectionSync.delay();

                        state.tmp.dygraph_user_action = true;
                        //NETDATA.globalSelectionSync.stop();
                        //NETDATA.globalSelectionSync.delay();
                        state.setMode('pan');
                        context.is2DPan = false;
                        Dygraph.movePan(event, dygraph, context);
                    }
                    else if(context.isZooming) {
                        //console.log('zooming...');

                        NETDATA.globalSelectionSync.stop();
                        NETDATA.globalSelectionSync.delay();

                        state.tmp.dygraph_user_action = true;
                        //NETDATA.globalSelectionSync.stop();
                        //NETDATA.globalSelectionSync.delay();
                        state.setMode('zoom');
                        Dygraph.moveZoom(event, dygraph, context);
                    }
                },
                mouseup: function(event, dygraph, context) {
                    state.tmp.dygraph_mouse_down = false;

                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.mouseup()');

                    if(state.tmp.dygraph_highlight_after !== null) {
                        //console.log('done highlight selection');

                        NETDATA.globalSelectionSync.stop();
                        NETDATA.globalSelectionSync.delay();

                        if (!(event.offsetX && event.offsetY)){
                            event.offsetX = event.layerX - event.target.offsetLeft;
                            event.offsetY = event.layerY - event.target.offsetTop;
                        }

                        NETDATA.globalChartUnderlay.set(state
                            , state.tmp.dygraph_highlight_after
                            , dygraph.toDataXCoord(event.offsetX)
                            , state.view_after
                            , state.view_before
                        );

                        state.tmp.dygraph_highlight_after = null;

                        context.isZooming = false;
                        dygraph.clearZoomRect_();
                        dygraph.drawGraph_(false);

                        // refresh all the charts immediately
                        NETDATA.options.auto_refresher_stop_until = 0;
                    }
                    else if (context.isPanning) {
                        //console.log('done panning');

                        NETDATA.globalSelectionSync.stop();
                        NETDATA.globalSelectionSync.delay();

                        state.tmp.dygraph_user_action = true;
                        Dygraph.endPan(event, dygraph, context);

                        // refresh all the charts immediately
                        NETDATA.options.auto_refresher_stop_until = 0;
                    }
                    else if (context.isZooming) {
                        //console.log('done zomming');

                        NETDATA.globalSelectionSync.stop();
                        NETDATA.globalSelectionSync.delay();

                        state.tmp.dygraph_user_action = true;
                        Dygraph.endZoom(event, dygraph, context);

                        // refresh all the charts immediately
                        NETDATA.options.auto_refresher_stop_until = 0;
                    }
                },
                click: function(event, dygraph, context) {
                    void(dygraph);
                    void(context);

                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.click()');

                    event.preventDefault();
                },
                dblclick: function(event, dygraph, context) {
                    void(event);
                    void(dygraph);
                    void(context);

                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.dblclick()');
                    NETDATA.resetAllCharts(state);
                },
                wheel: function(event, dygraph, context) {
                    void(context);

                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.wheel()');

                    // Take the offset of a mouse event on the dygraph canvas and
                    // convert it to a pair of percentages from the bottom left.
                    // (Not top left, bottom is where the lower value is.)
                    function offsetToPercentage(g, offsetX, offsetY) {
                        // This is calculating the pixel offset of the leftmost date.
                        var xOffset = g.toDomCoords(g.xAxisRange()[0], null)[0];
                        var yar0 = g.yAxisRange(0);

                        // This is calculating the pixel of the highest value. (Top pixel)
                        var yOffset = g.toDomCoords(null, yar0[1])[1];

                        // x y w and h are relative to the corner of the drawing area,
                        // so that the upper corner of the drawing area is (0, 0).
                        var x = offsetX - xOffset;
                        var y = offsetY - yOffset;

                        // This is computing the rightmost pixel, effectively defining the
                        // width.
                        var w = g.toDomCoords(g.xAxisRange()[1], null)[0] - xOffset;

                        // This is computing the lowest pixel, effectively defining the height.
                        var h = g.toDomCoords(null, yar0[0])[1] - yOffset;

                        // Percentage from the left.
                        var xPct = w === 0 ? 0 : (x / w);
                        // Percentage from the top.
                        var yPct = h === 0 ? 0 : (y / h);

                        // The (1-) part below changes it from "% distance down from the top"
                        // to "% distance up from the bottom".
                        return [xPct, (1-yPct)];
                    }

                    // Adjusts [x, y] toward each other by zoomInPercentage%
                    // Split it so the left/bottom axis gets xBias/yBias of that change and
                    // tight/top gets (1-xBias)/(1-yBias) of that change.
                    //
                    // If a bias is missing it splits it down the middle.
                    function zoomRange(g, zoomInPercentage, xBias, yBias) {
                        xBias = xBias || 0.5;
                        yBias = yBias || 0.5;

                        function adjustAxis(axis, zoomInPercentage, bias) {
                            var delta = axis[1] - axis[0];
                            var increment = delta * zoomInPercentage;
                            var foo = [increment * bias, increment * (1-bias)];

                            return [ axis[0] + foo[0], axis[1] - foo[1] ];
                        }

                        var yAxes = g.yAxisRanges();
                        var newYAxes = [];
                        for (var i = 0; i < yAxes.length; i++) {
                            newYAxes[i] = adjustAxis(yAxes[i], zoomInPercentage, yBias);
                        }

                        return adjustAxis(g.xAxisRange(), zoomInPercentage, xBias);
                    }

                    if(event.altKey || event.shiftKey) {
                        state.tmp.dygraph_user_action = true;

                        NETDATA.globalSelectionSync.stop();
                        NETDATA.globalSelectionSync.delay();

                        // http://dygraphs.com/gallery/interaction-api.js
                        var normal_def;
                        if(typeof event.wheelDelta === 'number' && !isNaN(event.wheelDelta))
                            // chrome
                            normal_def = event.wheelDelta / 40;
                        else
                            // firefox
                            normal_def = event.deltaY * -1.2;

                        var normal = (event.detail) ? event.detail * -1 : normal_def;
                        var percentage = normal / 50;

                        if (!(event.offsetX && event.offsetY)){
                            event.offsetX = event.layerX - event.target.offsetLeft;
                            event.offsetY = event.layerY - event.target.offsetTop;
                        }

                        var percentages = offsetToPercentage(dygraph, event.offsetX, event.offsetY);
                        var xPct = percentages[0];
                        var yPct = percentages[1];

                        var new_x_range = zoomRange(dygraph, percentage, xPct, yPct);
                        var after = new_x_range[0];
                        var before = new_x_range[1];

                        var first = state.netdata_first + state.data_update_every;
                        var last = state.netdata_last + state.data_update_every;

                        if(before > last) {
                            after -= (before - last);
                            before = last;
                        }
                        if(after < first) {
                            after = first;
                        }

                        state.setMode('zoom');
                        state.updateChartPanOrZoom(after, before, function() {
                            dygraph.updateOptions({ dateWindow: [ after, before ] });
                        });

                        event.preventDefault();
                    }
                },
                touchstart: function(event, dygraph, context) {
                    state.tmp.dygraph_mouse_down = true;

                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.touchstart()');

                    state.tmp.dygraph_user_action = true;
                    state.setMode('zoom');
                    state.pauseChart();

                    NETDATA.globalSelectionSync.stop();
                    NETDATA.globalSelectionSync.delay();

                    Dygraph.defaultInteractionModel.touchstart(event, dygraph, context);

                    // we overwrite the touch directions at the end, to overwrite
                    // the internal default of dygraph
                    context.touchDirections = { x: true, y: false };

                    state.dygraph_last_touch_start = Date.now();
                    state.dygraph_last_touch_move = 0;

                    if(typeof event.touches[0].pageX === 'number')
                        state.dygraph_last_touch_page_x = event.touches[0].pageX;
                    else
                        state.dygraph_last_touch_page_x = 0;
                },
                touchmove: function(event, dygraph, context) {
                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.touchmove()');

                    NETDATA.globalSelectionSync.stop();
                    NETDATA.globalSelectionSync.delay();

                    state.tmp.dygraph_user_action = true;
                    Dygraph.defaultInteractionModel.touchmove(event, dygraph, context);

                    state.dygraph_last_touch_move = Date.now();
                },
                touchend: function(event, dygraph, context) {
                    state.tmp.dygraph_mouse_down = false;

                    if(NETDATA.options.debug.dygraph === true || state.debug === true)
                        state.log('interactionModel.touchend()');

                    NETDATA.globalSelectionSync.stop();
                    NETDATA.globalSelectionSync.delay();

                    state.tmp.dygraph_user_action = true;
                    Dygraph.defaultInteractionModel.touchend(event, dygraph, context);

                    // if it didn't move, it is a selection
                    if(state.dygraph_last_touch_move === 0 && state.dygraph_last_touch_page_x !== 0) {
                        NETDATA.globalSelectionSync.dont_sync_before = 0;
                        NETDATA.globalSelectionSync.setMaster(state);

                        // internal api of dygraph
                        var pct = (state.dygraph_last_touch_page_x - (dygraph.plotter_.area.x + state.element.getBoundingClientRect().left)) / dygraph.plotter_.area.w;
                        console.log('pct: ' + pct.toString());

                        var t = Math.round(state.view_after + (state.view_before - state.view_after) * pct);
                        if(NETDATA.dygraphSetSelection(state, t) === true) {
                            NETDATA.globalSelectionSync.sync(state, t);
                        }
                    }

                    // if it was double tap within double click time, reset the charts
                    var now = Date.now();
                    if(typeof state.dygraph_last_touch_end !== 'undefined') {
                        if(state.dygraph_last_touch_move === 0) {
                            var dt = now - state.dygraph_last_touch_end;
                            if(dt <= NETDATA.options.current.double_click_speed)
                                NETDATA.resetAllCharts(state);
                        }
                    }

                    // remember the timestamp of the last touch end
                    state.dygraph_last_touch_end = now;

                    // refresh all the charts immediately
                    NETDATA.options.auto_refresher_stop_until = 0;
                }
            }
        };

        if(NETDATA.chartLibraries.dygraph.isSparkline(state)) {
            state.tmp.dygraph_options.drawGrid = false;
            state.tmp.dygraph_options.drawAxis = false;
            state.tmp.dygraph_options.title = undefined;
            state.tmp.dygraph_options.ylabel = undefined;
            state.tmp.dygraph_options.yLabelWidth = 0;
            state.tmp.dygraph_options.labelsDivWidth = 120;
            state.tmp.dygraph_options.labelsDivStyles.width = '120px';
            state.tmp.dygraph_options.labelsSeparateLines = true;
            state.tmp.dygraph_options.rightGap = 0;
            state.tmp.dygraph_options.yRangePad = 1;
        }

        if(smooth === true) {
            state.tmp.dygraph_smooth_eligible = true;

            if(NETDATA.options.current.smooth_plot === true)
                state.tmp.dygraph_options.plotter = smoothPlotter;
        }
        else state.tmp.dygraph_smooth_eligible = false;

        if(netdataSnapshotData !== null && NETDATA.globalPanAndZoom.isActive() === true && NETDATA.globalPanAndZoom.isMaster(state) === false) {
            // pan and zoom on snapshots
            state.tmp.dygraph_options.dateWindow = [ NETDATA.globalPanAndZoom.force_after_ms, NETDATA.globalPanAndZoom.force_before_ms ];
            state.tmp.dygraph_options.isZoomedIgnoreProgrammaticZoom = true;
        }

        state.tmp.dygraph_instance = new Dygraph(state.element_chart,
            data.result.data, state.tmp.dygraph_options);

        state.tmp.dygraph_force_zoom = false;
        state.tmp.dygraph_user_action = false;
        state.tmp.dygraph_last_rendered = Date.now();
        state.tmp.dygraph_highlight_after = null;

        if(state.tmp.dygraph_options.valueRange[0] === null && state.tmp.dygraph_options.valueRange[1] === null) {
            if (typeof state.tmp.dygraph_instance.axes_[0].extremeRange !== 'undefined') {
                state.tmp.__commonMin = NETDATA.dataAttribute(state.element, 'common-min', null);
                state.tmp.__commonMax = NETDATA.dataAttribute(state.element, 'common-max', null);
            }
            else {
                state.log('incompatible version of Dygraph detected');
                state.tmp.__commonMin = null;
                state.tmp.__commonMax = null;
            }
        }
        else {
            // if the user gave a valueRange, respect it
            state.tmp.__commonMin = null;
            state.tmp.__commonMax = null;
        }

        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // morris

    NETDATA.morrisInitialize = function(callback) {
        if(typeof netdataNoMorris === 'undefined' || !netdataNoMorris) {

            // morris requires raphael
            if(!NETDATA.chartLibraries.raphael.initialized) {
                if(NETDATA.chartLibraries.raphael.enabled) {
                    NETDATA.raphaelInitialize(function() {
                        NETDATA.morrisInitialize(callback);
                    });
                }
                else {
                    NETDATA.chartLibraries.morris.enabled = false;
                    if(typeof callback === "function")
                        return callback();
                }
            }
            else {
                NETDATA._loadCSS(NETDATA.morris_css);

                $.ajax({
                    url: NETDATA.morris_js,
                    cache: true,
                    dataType: "script",
                    xhrFields: { withCredentials: true } // required for the cookie
                })
                .done(function() {
                    NETDATA.registerChartLibrary('morris', NETDATA.morris_js);
                })
                .fail(function() {
                    NETDATA.chartLibraries.morris.enabled = false;
                    NETDATA.error(100, NETDATA.morris_js);
                })
                .always(function() {
                    if(typeof callback === "function")
                        return callback();
                });
            }
        }
        else {
            NETDATA.chartLibraries.morris.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.morrisChartUpdate = function(state, data) {
        state.morris_instance.setData(data.result.data);
        return true;
    };

    NETDATA.morrisChartCreate = function(state, data) {

        state.morris_options = {
                element: state.element_chart.id,
                data: data.result.data,
                xkey: 'time',
                ykeys: data.dimension_names,
                labels: data.dimension_names,
                lineWidth: 2,
                pointSize: 3,
                smooth: true,
                hideHover: 'auto',
                parseTime: true,
                continuousLine: false,
                behaveLikeLine: false
        };

        if(state.chart.chart_type === 'line')
            state.morris_instance = new Morris.Line(state.morris_options);

        else if(state.chart.chart_type === 'area') {
            state.morris_options.behaveLikeLine = true;
            state.morris_instance = new Morris.Area(state.morris_options);
        }
        else // stacked
            state.morris_instance = new Morris.Area(state.morris_options);

        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // raphael

    NETDATA.raphaelInitialize = function(callback) {
        if(typeof netdataStopRaphael === 'undefined' || !netdataStopRaphael) {
            $.ajax({
                url: NETDATA.raphael_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
            .done(function() {
                NETDATA.registerChartLibrary('raphael', NETDATA.raphael_js);
            })
            .fail(function() {
                NETDATA.chartLibraries.raphael.enabled = false;
                NETDATA.error(100, NETDATA.raphael_js);
            })
            .always(function() {
                if(typeof callback === "function")
                    return callback();
            });
        }
        else {
            NETDATA.chartLibraries.raphael.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.raphaelChartUpdate = function(state, data) {
        $(state.element_chart).raphael(data.result, {
            width: state.chartWidth(),
            height: state.chartHeight()
        });

        return false;
    };

    NETDATA.raphaelChartCreate = function(state, data) {
        $(state.element_chart).raphael(data.result, {
            width: state.chartWidth(),
            height: state.chartHeight()
        });

        return false;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // C3

    NETDATA.c3Initialize = function(callback) {
        if(typeof netdataNoC3 === 'undefined' || !netdataNoC3) {

            // C3 requires D3
            if(!NETDATA.chartLibraries.d3.initialized) {
                if(NETDATA.chartLibraries.d3.enabled) {
                    NETDATA.d3Initialize(function() {
                        NETDATA.c3Initialize(callback);
                    });
                }
                else {
                    NETDATA.chartLibraries.c3.enabled = false;
                    if(typeof callback === "function")
                        return callback();
                }
            }
            else {
                NETDATA._loadCSS(NETDATA.c3_css);

                $.ajax({
                    url: NETDATA.c3_js,
                    cache: true,
                    dataType: "script",
                    xhrFields: { withCredentials: true } // required for the cookie
                })
                .done(function() {
                    NETDATA.registerChartLibrary('c3', NETDATA.c3_js);
                })
                .fail(function() {
                    NETDATA.chartLibraries.c3.enabled = false;
                    NETDATA.error(100, NETDATA.c3_js);
                })
                .always(function() {
                    if(typeof callback === "function")
                        return callback();
                });
            }
        }
        else {
            NETDATA.chartLibraries.c3.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.c3ChartUpdate = function(state, data) {
        state.c3_instance.destroy();
        return NETDATA.c3ChartCreate(state, data);

        //state.c3_instance.load({
        //  rows: data.result,
        //  unload: true
        //});

        //return true;
    };

    NETDATA.c3ChartCreate = function(state, data) {

        state.element_chart.id = 'c3-' + state.uuid;
        // console.log('id = ' + state.element_chart.id);

        state.c3_instance = c3.generate({
            bindto: '#' + state.element_chart.id,
            size: {
                width: state.chartWidth(),
                height: state.chartHeight()
            },
            color: {
                pattern: state.chartColors()
            },
            data: {
                x: 'time',
                rows: data.result,
                type: (state.chart.chart_type === 'line')?'spline':'area-spline'
            },
            axis: {
                x: {
                    type: 'timeseries',
                    tick: {
                        format: function(x) {
                            return NETDATA.dateTime.xAxisTimeString(x);
                        }
                    }
                }
            },
            grid: {
                x: {
                    show: true
                },
                y: {
                    show: true
                }
            },
            point: {
                show: false
            },
            line: {
                connectNull: false
            },
            transition: {
                duration: 0
            },
            interaction: {
                enabled: true
            }
        });

        // console.log(state.c3_instance);

        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // D3

    NETDATA.d3Initialize = function(callback) {
        if(typeof netdataStopD3 === 'undefined' || !netdataStopD3) {
            $.ajax({
                url: NETDATA.d3_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
            .done(function() {
                NETDATA.registerChartLibrary('d3', NETDATA.d3_js);
            })
            .fail(function() {
                NETDATA.chartLibraries.d3.enabled = false;
                NETDATA.error(100, NETDATA.d3_js);
            })
            .always(function() {
                if(typeof callback === "function")
                    return callback();
            });
        }
        else {
            NETDATA.chartLibraries.d3.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.d3ChartUpdate = function(state, data) {
        void(state);
        void(data);

        return false;
    };

    NETDATA.d3ChartCreate = function(state, data) {
        void(state);
        void(data);

        return false;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // google charts

    NETDATA.googleInitialize = function(callback) {
        if(typeof netdataNoGoogleCharts === 'undefined' || !netdataNoGoogleCharts) {
            $.ajax({
                url: NETDATA.google_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
            .done(function() {
                NETDATA.registerChartLibrary('google', NETDATA.google_js);
                google.load('visualization', '1.1', {
                    'packages': ['corechart', 'controls'],
                    'callback': callback
                });
            })
            .fail(function() {
                NETDATA.chartLibraries.google.enabled = false;
                NETDATA.error(100, NETDATA.google_js);
                if(typeof callback === "function")
                    return callback();
            });
        }
        else {
            NETDATA.chartLibraries.google.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.googleChartUpdate = function(state, data) {
        var datatable = new google.visualization.DataTable(data.result);
        state.google_instance.draw(datatable, state.google_options);
        return true;
    };

    NETDATA.googleChartCreate = function(state, data) {
        var datatable = new google.visualization.DataTable(data.result);

        state.google_options = {
            colors: state.chartColors(),

            // do not set width, height - the chart resizes itself
            //width: state.chartWidth(),
            //height: state.chartHeight(),
            lineWidth: 1,
            title: state.title,
            fontSize: 11,
            hAxis: {
            //  title: "Time of Day",
            //  format:'HH:mm:ss',
                viewWindowMode: 'maximized',
                slantedText: false,
                format:'HH:mm:ss',
                textStyle: {
                    fontSize: 9
                },
                gridlines: {
                    color: '#EEE'
                }
            },
            vAxis: {
                title: state.units_current,
                viewWindowMode: 'pretty',
                minValue: -0.1,
                maxValue: 0.1,
                direction: 1,
                textStyle: {
                    fontSize: 9
                },
                gridlines: {
                    color: '#EEE'
                }
            },
            chartArea: {
                width: '65%',
                height: '80%'
            },
            focusTarget: 'category',
            annotation: {
                '1': {
                    style: 'line'
                }
            },
            pointsVisible: 0,
            titlePosition: 'out',
            titleTextStyle: {
                fontSize: 11
            },
            tooltip: {
                isHtml: false,
                ignoreBounds: true,
                textStyle: {
                    fontSize: 9
                }
            },
            curveType: 'function',
            areaOpacity: 0.3,
            isStacked: false
        };

        switch(state.chart.chart_type) {
            case "area":
                state.google_options.vAxis.viewWindowMode = 'maximized';
                state.google_options.areaOpacity = NETDATA.options.current.color_fill_opacity_area;
                state.google_instance = new google.visualization.AreaChart(state.element_chart);
                break;

            case "stacked":
                state.google_options.isStacked = true;
                state.google_options.areaOpacity = NETDATA.options.current.color_fill_opacity_stacked;
                state.google_options.vAxis.viewWindowMode = 'maximized';
                state.google_options.vAxis.minValue = null;
                state.google_options.vAxis.maxValue = null;
                state.google_instance = new google.visualization.AreaChart(state.element_chart);
                break;

            default:
            case "line":
                state.google_options.lineWidth = 2;
                state.google_instance = new google.visualization.LineChart(state.element_chart);
                break;
        }

        state.google_instance.draw(datatable, state.google_options);
        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------

    NETDATA.easypiechartPercentFromValueMinMax = function(state, value, min, max) {
        if(typeof value !== 'number') value = 0;
        if(typeof min !== 'number') min = 0;
        if(typeof max !== 'number') max = 0;

        if(min > max) {
            var t = min;
            min = max;
            max = t;
        }

        if(min > value) min = value;
        if(max < value) max = value;

        state.legendFormatValueDecimalsFromMinMax(min, max);

        if(state.tmp.easyPieChartMin === null && min > 0) min = 0;
        if(state.tmp.easyPieChartMax === null && max < 0) max = 0;

        var pcent;

        if(min < 0 && max > 0) {
            // it is both positive and negative
            // zero at the top center of the chart
            max = (-min > max)? -min : max;
            pcent = Math.round(value * 100 / max);
        }
        else if(value >= 0 && min >= 0 && max >= 0) {
            // clockwise
            pcent = Math.round((value - min) * 100 / (max - min));
            if(pcent === 0) pcent = 0.1;
        }
        else {
            // counter clockwise
            pcent = Math.round((value - max) * 100 / (max - min));
            if(pcent === 0) pcent = -0.1;
        }

        return pcent;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // easy-pie-chart

    NETDATA.easypiechartInitialize = function(callback) {
        if(typeof netdataNoEasyPieChart === 'undefined' || !netdataNoEasyPieChart) {
            $.ajax({
                url: NETDATA.easypiechart_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
                .done(function() {
                    NETDATA.registerChartLibrary('easypiechart', NETDATA.easypiechart_js);
                })
                .fail(function() {
                    NETDATA.chartLibraries.easypiechart.enabled = false;
                    NETDATA.error(100, NETDATA.easypiechart_js);
                })
                .always(function() {
                    if(typeof callback === "function")
                        return callback();
                })
        }
        else {
            NETDATA.chartLibraries.easypiechart.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.easypiechartClearSelection = function(state) {
        if(typeof state.tmp.easyPieChartEvent !== 'undefined') {
            if(state.tmp.easyPieChartEvent.timer) {
                NETDATA.timeout.clear(state.tmp.easyPieChartEvent.timer);
            }

            state.tmp.easyPieChartEvent.timer = undefined;
        }

        if(state.isAutoRefreshable() === true && state.data !== null) {
            NETDATA.easypiechartChartUpdate(state, state.data);
        }
        else {
            state.tmp.easyPieChartLabel.innerText = state.legendFormatValue(null);
            state.tmp.easyPieChart_instance.update(0);
        }
        state.tmp.easyPieChart_instance.enableAnimation();

        return true;
    };

    NETDATA.easypiechartSetSelection = function(state, t) {
        if(state.timeIsVisible(t) !== true)
            return NETDATA.easypiechartClearSelection(state);

        var slot = state.calculateRowForTime(t);
        if(slot < 0 || slot >= state.data.result.length)
            return NETDATA.easypiechartClearSelection(state);

        if(typeof state.tmp.easyPieChartEvent === 'undefined') {
            state.tmp.easyPieChartEvent = {
                timer: undefined,
                value: 0,
                pcent: 0
            };
        }

        var value = state.data.result[state.data.result.length - 1 - slot];
        var min = (state.tmp.easyPieChartMin === null)?NETDATA.commonMin.get(state):state.tmp.easyPieChartMin;
        var max = (state.tmp.easyPieChartMax === null)?NETDATA.commonMax.get(state):state.tmp.easyPieChartMax;
        var pcent = NETDATA.easypiechartPercentFromValueMinMax(state, value, min, max);

        state.tmp.easyPieChartEvent.value = value;
        state.tmp.easyPieChartEvent.pcent = pcent;
        state.tmp.easyPieChartLabel.innerText = state.legendFormatValue(value);

        if(state.tmp.easyPieChartEvent.timer === undefined) {
            state.tmp.easyPieChart_instance.disableAnimation();

            state.tmp.easyPieChartEvent.timer = NETDATA.timeout.set(function() {
                state.tmp.easyPieChartEvent.timer = undefined;
                state.tmp.easyPieChart_instance.update(state.tmp.easyPieChartEvent.pcent);
            }, 0);
        }

        return true;
    };

    NETDATA.easypiechartChartUpdate = function(state, data) {
        var value, min, max, pcent;

        if(NETDATA.globalPanAndZoom.isActive() === true || state.isAutoRefreshable() === false) {
            value = null;
            pcent = 0;
        }
        else {
            value = data.result[0];
            min = (state.tmp.easyPieChartMin === null)?NETDATA.commonMin.get(state):state.tmp.easyPieChartMin;
            max = (state.tmp.easyPieChartMax === null)?NETDATA.commonMax.get(state):state.tmp.easyPieChartMax;
            pcent = NETDATA.easypiechartPercentFromValueMinMax(state, value, min, max);
        }

        state.tmp.easyPieChartLabel.innerText = state.legendFormatValue(value);
        state.tmp.easyPieChart_instance.update(pcent);
        return true;
    };

    NETDATA.easypiechartChartCreate = function(state, data) {
        var chart = $(state.element_chart);

        var value = data.result[0];
        var min = NETDATA.dataAttribute(state.element, 'easypiechart-min-value', null);
        var max = NETDATA.dataAttribute(state.element, 'easypiechart-max-value', null);

        if(min === null) {
            min = NETDATA.commonMin.get(state);
            state.tmp.easyPieChartMin = null;
        }
        else
            state.tmp.easyPieChartMin = min;

        if(max === null) {
            max = NETDATA.commonMax.get(state);
            state.tmp.easyPieChartMax = null;
        }
        else
            state.tmp.easyPieChartMax = max;

        var size = state.chartWidth();
        var stroke = Math.floor(size / 22);
        if(stroke < 3) stroke = 2;

        var valuefontsize = Math.floor((size * 2 / 3) / 5);
        var valuetop = Math.round((size - valuefontsize - (size / 40)) / 2);
        state.tmp.easyPieChartLabel = document.createElement('span');
        state.tmp.easyPieChartLabel.className = 'easyPieChartLabel';
        state.tmp.easyPieChartLabel.innerText = state.legendFormatValue(value);
        state.tmp.easyPieChartLabel.style.fontSize = valuefontsize + 'px';
        state.tmp.easyPieChartLabel.style.top = valuetop.toString() + 'px';
        state.element_chart.appendChild(state.tmp.easyPieChartLabel);

        var titlefontsize = Math.round(valuefontsize * 1.6 / 3);
        var titletop = Math.round(valuetop - (titlefontsize * 2) - (size / 40));
        state.tmp.easyPieChartTitle = document.createElement('span');
        state.tmp.easyPieChartTitle.className = 'easyPieChartTitle';
        state.tmp.easyPieChartTitle.innerText = state.title;
        state.tmp.easyPieChartTitle.style.fontSize = titlefontsize + 'px';
        state.tmp.easyPieChartTitle.style.lineHeight = titlefontsize + 'px';
        state.tmp.easyPieChartTitle.style.top = titletop.toString() + 'px';
        state.element_chart.appendChild(state.tmp.easyPieChartTitle);

        var unitfontsize = Math.round(titlefontsize * 0.9);
        var unittop = Math.round(valuetop + (valuefontsize + unitfontsize) + (size / 40));
        state.tmp.easyPieChartUnits = document.createElement('span');
        state.tmp.easyPieChartUnits.className = 'easyPieChartUnits';
        state.tmp.easyPieChartUnits.innerText = state.units_current;
        state.tmp.easyPieChartUnits.style.fontSize = unitfontsize + 'px';
        state.tmp.easyPieChartUnits.style.top = unittop.toString() + 'px';
        state.element_chart.appendChild(state.tmp.easyPieChartUnits);

        var barColor = NETDATA.dataAttribute(state.element, 'easypiechart-barcolor', undefined);
        if(typeof barColor === 'undefined' || barColor === null)
            barColor = state.chartCustomColors()[0];
        else {
            // <div ... data-easypiechart-barcolor="(function(percent){return(percent < 50 ? '#5cb85c' : percent < 85 ? '#f0ad4e' : '#cb3935');})" ...></div>
            var tmp = eval(barColor);
            if(typeof tmp === 'function')
                barColor = tmp;
        }

        var pcent = NETDATA.easypiechartPercentFromValueMinMax(state, value, min, max);
        chart.data('data-percent', pcent);

        chart.easyPieChart({
            barColor: barColor,
            trackColor: NETDATA.dataAttribute(state.element, 'easypiechart-trackcolor', NETDATA.themes.current.easypiechart_track),
            scaleColor: NETDATA.dataAttribute(state.element, 'easypiechart-scalecolor', NETDATA.themes.current.easypiechart_scale),
            scaleLength: NETDATA.dataAttribute(state.element, 'easypiechart-scalelength', 5),
            lineCap: NETDATA.dataAttribute(state.element, 'easypiechart-linecap', 'round'),
            lineWidth: NETDATA.dataAttribute(state.element, 'easypiechart-linewidth', stroke),
            trackWidth: NETDATA.dataAttribute(state.element, 'easypiechart-trackwidth', undefined),
            size: NETDATA.dataAttribute(state.element, 'easypiechart-size', size),
            rotate: NETDATA.dataAttribute(state.element, 'easypiechart-rotate', 0),
            animate: NETDATA.dataAttribute(state.element, 'easypiechart-animate', {duration: 500, enabled: true}),
            easing: NETDATA.dataAttribute(state.element, 'easypiechart-easing', undefined)
        });

        // when we just re-create the chart
        // do not animate the first update
        var animate = true;
        if(typeof state.tmp.easyPieChart_instance !== 'undefined')
            animate = false;

        state.tmp.easyPieChart_instance = chart.data('easyPieChart');
        if(animate === false) state.tmp.easyPieChart_instance.disableAnimation();
        state.tmp.easyPieChart_instance.update(pcent);
        if(animate === false) state.tmp.easyPieChart_instance.enableAnimation();

        state.legendSetUnitsString = function(units) {
            if(typeof state.tmp.easyPieChartUnits !== 'undefined')
                state.tmp.easyPieChartUnits.innerText = units;
        };
        state.legendShowUndefined = function() {
            if(typeof state.tmp.easyPieChart_instance !== 'undefined')
                NETDATA.easypiechartClearSelection(state);
        };

        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // gauge.js

    NETDATA.gaugeInitialize = function(callback) {
        if(typeof netdataNoGauge === 'undefined' || !netdataNoGauge) {
            $.ajax({
                url: NETDATA.gauge_js,
                cache: true,
                dataType: "script",
                xhrFields: { withCredentials: true } // required for the cookie
            })
                .done(function() {
                    NETDATA.registerChartLibrary('gauge', NETDATA.gauge_js);
                })
                .fail(function() {
                    NETDATA.chartLibraries.gauge.enabled = false;
                    NETDATA.error(100, NETDATA.gauge_js);
                })
                .always(function() {
                    if(typeof callback === "function")
                        return callback();
                })
        }
        else {
            NETDATA.chartLibraries.gauge.enabled = false;
            if(typeof callback === "function")
                return callback();
        }
    };

    NETDATA.gaugeAnimation = function(state, status) {
        var speed = 32;

        if(typeof status === 'boolean' && status === false)
            speed = 1000000000;
        else if(typeof status === 'number')
            speed = status;

        // console.log('gauge speed ' + speed);
        state.tmp.gauge_instance.animationSpeed = speed;
        state.tmp.___gaugeOld__.speed = speed;
    };

    NETDATA.gaugeSet = function(state, value, min, max) {
        if(typeof value !== 'number') value = 0;
        if(typeof min !== 'number') min = 0;
        if(typeof max !== 'number') max = 0;
        if(value > max) max = value;
        if(value < min) min = value;
        if(min > max) {
            var t = min;
            min = max;
            max = t;
        }
        else if(min === max)
            max = min + 1;

        state.legendFormatValueDecimalsFromMinMax(min, max);

        // gauge.js has an issue if the needle
        // is smaller than min or larger than max
        // when we set the new values
        // the needle will go crazy

        // to prevent it, we always feed it
        // with a percentage, so that the needle
        // is always between min and max
        var pcent = (value - min) * 100 / (max - min);

        // bug fix for gauge.js 1.3.1
        // if the value is the absolute min or max, the chart is broken
        if(pcent < 0.001) pcent = 0.001;
        if(pcent > 99.999) pcent = 99.999;

        state.tmp.gauge_instance.set(pcent);
        // console.log('gauge set ' + pcent + ', value ' + value + ', min ' + min + ', max ' + max);

        state.tmp.___gaugeOld__.value = value;
        state.tmp.___gaugeOld__.min = min;
        state.tmp.___gaugeOld__.max = max;
    };

    NETDATA.gaugeSetLabels = function(state, value, min, max) {
        if(state.tmp.___gaugeOld__.valueLabel !== value) {
            state.tmp.___gaugeOld__.valueLabel = value;
            state.tmp.gaugeChartLabel.innerText = state.legendFormatValue(value);
        }
        if(state.tmp.___gaugeOld__.minLabel !== min) {
            state.tmp.___gaugeOld__.minLabel = min;
            state.tmp.gaugeChartMin.innerText = state.legendFormatValue(min);
        }
        if(state.tmp.___gaugeOld__.maxLabel !== max) {
            state.tmp.___gaugeOld__.maxLabel = max;
            state.tmp.gaugeChartMax.innerText = state.legendFormatValue(max);
        }
    };

    NETDATA.gaugeClearSelection = function(state) {
        if(typeof state.tmp.gaugeEvent !== 'undefined') {
            if(state.tmp.gaugeEvent.timer) {
                NETDATA.timeout.clear(state.tmp.gaugeEvent.timer);
            }

            state.tmp.gaugeEvent.timer = undefined;
        }

        if(state.isAutoRefreshable() === true && state.data !== null) {
            NETDATA.gaugeChartUpdate(state, state.data);
        }
        else {
            NETDATA.gaugeAnimation(state, false);
            NETDATA.gaugeSet(state, null, null, null);
            NETDATA.gaugeSetLabels(state, null, null, null);
        }

        NETDATA.gaugeAnimation(state, true);
        return true;
    };

    NETDATA.gaugeSetSelection = function(state, t) {
        if(state.timeIsVisible(t) !== true)
            return NETDATA.gaugeClearSelection(state);

        var slot = state.calculateRowForTime(t);
        if(slot < 0 || slot >= state.data.result.length)
            return NETDATA.gaugeClearSelection(state);

        if(typeof state.tmp.gaugeEvent === 'undefined') {
            state.tmp.gaugeEvent = {
                timer: undefined,
                value: 0,
                min: 0,
                max: 0
            };
        }

        var value = state.data.result[state.data.result.length - 1 - slot];
        var min = (state.tmp.gaugeMin === null)?NETDATA.commonMin.get(state):state.tmp.gaugeMin;
        var max = (state.tmp.gaugeMax === null)?NETDATA.commonMax.get(state):state.tmp.gaugeMax;

        // make sure it is zero based
        // but only if it has not been set by the user
        if(state.tmp.gaugeMin === null && min > 0) min = 0;
        if(state.tmp.gaugeMax === null && max < 0) max = 0;

        state.tmp.gaugeEvent.value = value;
        state.tmp.gaugeEvent.min = min;
        state.tmp.gaugeEvent.max = max;
        NETDATA.gaugeSetLabels(state, value, min, max);

        if(state.tmp.gaugeEvent.timer === undefined) {
            NETDATA.gaugeAnimation(state, false);

            state.tmp.gaugeEvent.timer = NETDATA.timeout.set(function() {
                state.tmp.gaugeEvent.timer = undefined;
                NETDATA.gaugeSet(state, state.tmp.gaugeEvent.value, state.tmp.gaugeEvent.min, state.tmp.gaugeEvent.max);
            }, 0);
        }

        return true;
    };

    NETDATA.gaugeChartUpdate = function(state, data) {
        var value, min, max;

        if(NETDATA.globalPanAndZoom.isActive() === true || state.isAutoRefreshable() === false) {
            NETDATA.gaugeSetLabels(state, null, null, null);
            state.tmp.gauge_instance.set(0);
        }
        else {
            value = data.result[0];
            min = (state.tmp.gaugeMin === null)?NETDATA.commonMin.get(state):state.tmp.gaugeMin;
            max = (state.tmp.gaugeMax === null)?NETDATA.commonMax.get(state):state.tmp.gaugeMax;
            if(value < min) min = value;
            if(value > max) max = value;

            // make sure it is zero based
            // but only if it has not been set by the user
            if(state.tmp.gaugeMin === null && min > 0) min = 0;
            if(state.tmp.gaugeMax === null && max < 0) max = 0;

            NETDATA.gaugeSet(state, value, min, max);
            NETDATA.gaugeSetLabels(state, value, min, max);
        }

        return true;
    };

    NETDATA.gaugeChartCreate = function(state, data) {
        // var chart = $(state.element_chart);

        var value = data.result[0];
        var min = NETDATA.dataAttribute(state.element, 'gauge-min-value', null);
        var max = NETDATA.dataAttribute(state.element, 'gauge-max-value', null);
        // var adjust = NETDATA.dataAttribute(state.element, 'gauge-adjust', null);
        var pointerColor = NETDATA.dataAttribute(state.element, 'gauge-pointer-color', NETDATA.themes.current.gauge_pointer);
        var strokeColor = NETDATA.dataAttribute(state.element, 'gauge-stroke-color', NETDATA.themes.current.gauge_stroke);
        var startColor = NETDATA.dataAttribute(state.element, 'gauge-start-color', state.chartCustomColors()[0]);
        var stopColor = NETDATA.dataAttribute(state.element, 'gauge-stop-color', void 0);
        var generateGradient = NETDATA.dataAttribute(state.element, 'gauge-generate-gradient', false);

        if(min === null) {
            min = NETDATA.commonMin.get(state);
            state.tmp.gaugeMin = null;
        }
        else
            state.tmp.gaugeMin = min;

        if(max === null) {
            max = NETDATA.commonMax.get(state);
            state.tmp.gaugeMax = null;
        }
        else
            state.tmp.gaugeMax = max;

        // make sure it is zero based
        // but only if it has not been set by the user
        if(state.tmp.gaugeMin === null && min > 0) min = 0;
        if(state.tmp.gaugeMax === null && max < 0) max = 0;

        var width = state.chartWidth(), height = state.chartHeight(); //, ratio = 1.5;
        // console.log('gauge width: ' + width.toString() + ', height: ' + height.toString());
        //switch(adjust) {
        //  case 'width': width = height * ratio; break;
        //  case 'height':
        //  default: height = width / ratio; break;
        //}
        //state.element.style.width = width.toString() + 'px';
        //state.element.style.height = height.toString() + 'px';

        var lum_d = 0.05;

        var options = {
            lines: 12,                  // The number of lines to draw
            angle: 0.14,                // The span of the gauge arc
            lineWidth: 0.57,            // The line thickness
            radiusScale: 1.0,           // Relative radius
            pointer: {
                length: 0.85,           // 0.9 The radius of the inner circle
                strokeWidth: 0.045,     // The rotation offset
                color: pointerColor     // Fill color
            },
            limitMax: true,             // If false, the max value of the gauge will be updated if value surpass max
            limitMin: true,             // If true, the min value of the gauge will be fixed unless you set it manually
            colorStart: startColor,     // Colors
            colorStop: stopColor,       // just experiment with them
            strokeColor: strokeColor,   // to see which ones work best for you
            generateGradient: (generateGradient === true),
            gradientType: 0,
            highDpiSupport: true        // High resolution support
        };

        if (generateGradient.constructor === Array) {
            // example options:
            // data-gauge-generate-gradient="[0, 50, 100]"
            // data-gauge-gradient-percent-color-0="#FFFFFF"
            // data-gauge-gradient-percent-color-50="#999900"
            // data-gauge-gradient-percent-color-100="#000000"

            options.percentColors = [];
            var len = generateGradient.length;
            while(len--) {
                var pcent = generateGradient[len];
                var color = NETDATA.dataAttribute(state.element, 'gauge-gradient-percent-color-' + pcent.toString(), false);
                if(color !== false) {
                    var a = [];
                    a[0] = pcent / 100;
                    a[1] = color;
                    options.percentColors.unshift(a);
                }
            }
            if(options.percentColors.length === 0)
                delete options.percentColors;
        }
        else if(generateGradient === false && NETDATA.themes.current.gauge_gradient === true) {
            //noinspection PointlessArithmeticExpressionJS
            options.percentColors = [
                [0.0, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 0))],
                [0.1, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 1))],
                [0.2, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 2))],
                [0.3, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 3))],
                [0.4, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 4))],
                [0.5, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 5))],
                [0.6, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 6))],
                [0.7, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 7))],
                [0.8, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 8))],
                [0.9, NETDATA.colorLuminance(startColor, (lum_d * 10) - (lum_d * 9))],
                [1.0, NETDATA.colorLuminance(startColor, 0.0)]];
        }

        state.tmp.gauge_canvas = document.createElement('canvas');
        state.tmp.gauge_canvas.id = 'gauge-' + state.uuid + '-canvas';
        state.tmp.gauge_canvas.className = 'gaugeChart';
        state.tmp.gauge_canvas.width  = width;
        state.tmp.gauge_canvas.height = height;
        state.element_chart.appendChild(state.tmp.gauge_canvas);

        var valuefontsize = Math.floor(height / 5);
        var valuetop = Math.round((height - valuefontsize) / 3.2);
        state.tmp.gaugeChartLabel = document.createElement('span');
        state.tmp.gaugeChartLabel.className = 'gaugeChartLabel';
        state.tmp.gaugeChartLabel.style.fontSize = valuefontsize + 'px';
        state.tmp.gaugeChartLabel.style.top = valuetop.toString() + 'px';
        state.element_chart.appendChild(state.tmp.gaugeChartLabel);

        var titlefontsize = Math.round(valuefontsize / 2.1);
        var titletop = 0;
        state.tmp.gaugeChartTitle = document.createElement('span');
        state.tmp.gaugeChartTitle.className = 'gaugeChartTitle';
        state.tmp.gaugeChartTitle.innerText = state.title;
        state.tmp.gaugeChartTitle.style.fontSize = titlefontsize + 'px';
        state.tmp.gaugeChartTitle.style.lineHeight = titlefontsize + 'px';
        state.tmp.gaugeChartTitle.style.top = titletop.toString() + 'px';
        state.element_chart.appendChild(state.tmp.gaugeChartTitle);

        var unitfontsize = Math.round(titlefontsize * 0.9);
        state.tmp.gaugeChartUnits = document.createElement('span');
        state.tmp.gaugeChartUnits.className = 'gaugeChartUnits';
        state.tmp.gaugeChartUnits.innerText = state.units_current;
        state.tmp.gaugeChartUnits.style.fontSize = unitfontsize + 'px';
        state.element_chart.appendChild(state.tmp.gaugeChartUnits);

        state.tmp.gaugeChartMin = document.createElement('span');
        state.tmp.gaugeChartMin.className = 'gaugeChartMin';
        state.tmp.gaugeChartMin.style.fontSize = Math.round(valuefontsize * 0.75).toString() + 'px';
        state.element_chart.appendChild(state.tmp.gaugeChartMin);

        state.tmp.gaugeChartMax = document.createElement('span');
        state.tmp.gaugeChartMax.className = 'gaugeChartMax';
        state.tmp.gaugeChartMax.style.fontSize = Math.round(valuefontsize * 0.75).toString() + 'px';
        state.element_chart.appendChild(state.tmp.gaugeChartMax);

        // when we just re-create the chart
        // do not animate the first update
        var animate = true;
        if(typeof state.tmp.gauge_instance !== 'undefined')
            animate = false;

        state.tmp.gauge_instance = new Gauge(state.tmp.gauge_canvas).setOptions(options); // create sexy gauge!

        state.tmp.___gaugeOld__ = {
            value: value,
            min: min,
            max: max,
            valueLabel: null,
            minLabel: null,
            maxLabel: null
        };

        // we will always feed a percentage
        state.tmp.gauge_instance.minValue = 0;
        state.tmp.gauge_instance.maxValue = 100;

        NETDATA.gaugeAnimation(state, animate);
        NETDATA.gaugeSet(state, value, min, max);
        NETDATA.gaugeSetLabels(state, value, min, max);
        NETDATA.gaugeAnimation(state, true);

        state.legendSetUnitsString = function(units) {
            if(typeof state.tmp.gaugeChartUnits !== 'undefined') {
                state.tmp.gaugeChartUnits.innerText = units;
                state.tmp.___gaugeOld__.valueLabel = null;
                state.tmp.___gaugeOld__.minLabel = null;
                state.tmp.___gaugeOld__.maxLabel = null;
            }
        };
        state.legendShowUndefined = function() {
            if(typeof state.tmp.gauge_instance !== 'undefined')
                NETDATA.gaugeClearSelection(state);
        };

        return true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Charts Libraries Registration

    NETDATA.chartLibraries = {
        "dygraph": {
            initialize: NETDATA.dygraphInitialize,
            create: NETDATA.dygraphChartCreate,
            update: NETDATA.dygraphChartUpdate,
            resize: function(state) {
                if(typeof state.tmp.dygraph_instance !== 'undefined' && typeof state.tmp.dygraph_instance.resize === 'function')
                    state.tmp.dygraph_instance.resize();
            },
            setSelection: NETDATA.dygraphSetSelection,
            clearSelection:  NETDATA.dygraphClearSelection,
            toolboxPanAndZoom: NETDATA.dygraphToolboxPanAndZoom,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'json'; },
            options: function(state) { void(state); return 'ms|flip'; },
            legend: function(state) {
                return (this.isSparkline(state) === false)?'right-side':null;
            },
            autoresize: function(state) { void(state); return true; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return true; },
            pixels_per_point: function(state) {
                return (this.isSparkline(state) === false)?3:2;
            },
            isSparkline: function(state) {
                if(typeof state.tmp.dygraph_sparkline === 'undefined') {
                    var t = NETDATA.dataAttribute(state.element, 'dygraph-theme', undefined);
                    state.tmp.dygraph_sparkline = (t === 'sparkline');
                }
                return state.tmp.dygraph_sparkline;
            },
            container_class: function(state) {
                if(this.legend(state) !== null)
                    return 'netdata-container-with-legend';
                return 'netdata-container';
            }
        },
        "sparkline": {
            initialize: NETDATA.sparklineInitialize,
            create: NETDATA.sparklineChartCreate,
            update: NETDATA.sparklineChartUpdate,
            resize: null,
            setSelection: undefined, // function(state, t) { void(state); return true; },
            clearSelection: undefined, // function(state) { void(state); return true; },
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'array'; },
            options: function(state) { void(state); return 'flip|abs'; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return false; },
            pixels_per_point: function(state) { void(state); return 3; },
            container_class: function(state) { void(state); return 'netdata-container'; }
        },
        "peity": {
            initialize: NETDATA.peityInitialize,
            create: NETDATA.peityChartCreate,
            update: NETDATA.peityChartUpdate,
            resize: null,
            setSelection: undefined, // function(state, t) { void(state); return true; },
            clearSelection: undefined, // function(state) { void(state); return true; },
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'ssvcomma'; },
            options: function(state) { void(state); return 'null2zero|flip|abs'; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return false; },
            pixels_per_point: function(state) { void(state); return 3; },
            container_class: function(state) { void(state); return 'netdata-container'; }
        },
        "morris": {
            initialize: NETDATA.morrisInitialize,
            create: NETDATA.morrisChartCreate,
            update: NETDATA.morrisChartUpdate,
            resize: null,
            setSelection: undefined, // function(state, t) { void(state); return true; },
            clearSelection: undefined, // function(state) { void(state); return true; },
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'json'; },
            options: function(state) { void(state); return 'objectrows|ms'; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 50; },
            track_colors: function(state) { void(state); return false; },
            pixels_per_point: function(state) { void(state); return 15; },
            container_class: function(state) { void(state); return 'netdata-container'; }
        },
        "google": {
            initialize: NETDATA.googleInitialize,
            create: NETDATA.googleChartCreate,
            update: NETDATA.googleChartUpdate,
            resize: null,
            setSelection: undefined, //function(state, t) { void(state); return true; },
            clearSelection: undefined, //function(state) { void(state); return true; },
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'datatable'; },
            options: function(state) { void(state); return ''; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 300; },
            track_colors: function(state) { void(state); return false; },
            pixels_per_point: function(state) { void(state); return 4; },
            container_class: function(state) { void(state); return 'netdata-container'; }
        },
        "raphael": {
            initialize: NETDATA.raphaelInitialize,
            create: NETDATA.raphaelChartCreate,
            update: NETDATA.raphaelChartUpdate,
            resize: null,
            setSelection: undefined, // function(state, t) { void(state); return true; },
            clearSelection: undefined, // function(state) { void(state); return true; },
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'json'; },
            options: function(state) { void(state); return ''; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return false; },
            pixels_per_point: function(state) { void(state); return 3; },
            container_class: function(state) { void(state); return 'netdata-container'; }
        },
        "c3": {
            initialize: NETDATA.c3Initialize,
            create: NETDATA.c3ChartCreate,
            update: NETDATA.c3ChartUpdate,
            resize: null,
            setSelection: undefined, // function(state, t) { void(state); return true; },
            clearSelection: undefined, // function(state) { void(state); return true; },
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'csvjsonarray'; },
            options: function(state) { void(state); return 'milliseconds'; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return false; },
            pixels_per_point: function(state) { void(state); return 15; },
            container_class: function(state) { void(state); return 'netdata-container'; }
        },
        "d3": {
            initialize: NETDATA.d3Initialize,
            create: NETDATA.d3ChartCreate,
            update: NETDATA.d3ChartUpdate,
            resize: null,
            setSelection: undefined, // function(state, t) { void(state); return true; },
            clearSelection: undefined, // function(state) { void(state); return true; },
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'json'; },
            options: function(state) { void(state); return ''; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return false; },
            pixels_per_point: function(state) { void(state); return 3; },
            container_class: function(state) { void(state); return 'netdata-container'; }
        },
        "easypiechart": {
            initialize: NETDATA.easypiechartInitialize,
            create: NETDATA.easypiechartChartCreate,
            update: NETDATA.easypiechartChartUpdate,
            resize: null,
            setSelection: NETDATA.easypiechartSetSelection,
            clearSelection: NETDATA.easypiechartClearSelection,
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'array'; },
            options: function(state) { void(state); return 'absolute'; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return true; },
            pixels_per_point: function(state) { void(state); return 3; },
            aspect_ratio: 100,
            container_class: function(state) { void(state); return 'netdata-container-easypiechart'; }
        },
        "gauge": {
            initialize: NETDATA.gaugeInitialize,
            create: NETDATA.gaugeChartCreate,
            update: NETDATA.gaugeChartUpdate,
            resize: null,
            setSelection: NETDATA.gaugeSetSelection,
            clearSelection: NETDATA.gaugeClearSelection,
            toolboxPanAndZoom: null,
            initialized: false,
            enabled: true,
            format: function(state) { void(state); return 'array'; },
            options: function(state) { void(state); return 'absolute'; },
            legend: function(state) { void(state); return null; },
            autoresize: function(state) { void(state); return false; },
            max_updates_to_recreate: function(state) { void(state); return 5000; },
            track_colors: function(state) { void(state); return true; },
            pixels_per_point: function(state) { void(state); return 3; },
            aspect_ratio: 60,
            container_class: function(state) { void(state); return 'netdata-container-gauge'; }
        }
    };

    NETDATA.registerChartLibrary = function(library, url) {
        if(NETDATA.options.debug.libraries === true)
            console.log("registering chart library: " + library);

        NETDATA.chartLibraries[library].url = url;
        NETDATA.chartLibraries[library].initialized = true;
        NETDATA.chartLibraries[library].enabled = true;
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Load required JS libraries and CSS

    NETDATA.requiredJs = [
        {
            url: NETDATA.serverStatic + 'lib/bootstrap-3.3.7.min.js',
            async: false,
            isAlreadyLoaded: function() {
                // check if bootstrap is loaded
                if(typeof $().emulateTransitionEnd === 'function')
                    return true;
                else {
                    return (typeof netdataNoBootstrap !== 'undefined' && netdataNoBootstrap === true);
                }
            }
        },
        {
            url: NETDATA.serverStatic + 'lib/fontawesome-all-5.0.1.min.js',
            async: true,
            isAlreadyLoaded: function() { return false; }
        },
        {
            url: NETDATA.serverStatic + 'lib/perfect-scrollbar-0.6.15.min.js',
            isAlreadyLoaded: function() { return false; }
        }
    ];

    NETDATA.requiredCSS = [
        {
            url: NETDATA.themes.current.bootstrap_css,
            isAlreadyLoaded: function() {
                return (typeof netdataNoBootstrap !== 'undefined' && netdataNoBootstrap === true);
            }
        },
        {
            url: NETDATA.themes.current.dashboard_css,
            isAlreadyLoaded: function() { return false; }
        }
    ];

    NETDATA.loadedRequiredJs = 0;
    NETDATA.loadRequiredJs = function(index, callback) {
        if(index >= NETDATA.requiredJs.length) {
            if(typeof callback === 'function')
                return callback();
            return;
        }

        if(NETDATA.requiredJs[index].isAlreadyLoaded()) {
            NETDATA.loadedRequiredJs++;
            NETDATA.loadRequiredJs(++index, callback);
            return;
        }

        if(NETDATA.options.debug.main_loop === true)
            console.log('loading ' + NETDATA.requiredJs[index].url);

        var async = true;
        if(typeof NETDATA.requiredJs[index].async !== 'undefined' && NETDATA.requiredJs[index].async === false)
            async = false;

        $.ajax({
            url: NETDATA.requiredJs[index].url,
            cache: true,
            dataType: "script",
            xhrFields: { withCredentials: true } // required for the cookie
        })
        .done(function() {
            if(NETDATA.options.debug.main_loop === true)
                console.log('loaded ' + NETDATA.requiredJs[index].url);
        })
        .fail(function() {
            alert('Cannot load required JS library: ' + NETDATA.requiredJs[index].url);
        })
        .always(function() {
            NETDATA.loadedRequiredJs++;

            if(async === false)
                NETDATA.loadRequiredJs(++index, callback);
        });

        if(async === true)
            NETDATA.loadRequiredJs(++index, callback);
    };

    NETDATA.loadRequiredCSS = function(index) {
        if(index >= NETDATA.requiredCSS.length)
            return;

        if(NETDATA.requiredCSS[index].isAlreadyLoaded()) {
            NETDATA.loadRequiredCSS(++index);
            return;
        }

        if(NETDATA.options.debug.main_loop === true)
            console.log('loading ' + NETDATA.requiredCSS[index].url);

        NETDATA._loadCSS(NETDATA.requiredCSS[index].url);
        NETDATA.loadRequiredCSS(++index);
    };


    // ----------------------------------------------------------------------------------------------------------------
    // Registry of netdata hosts

    NETDATA.alarms = {
        onclick: null,                  // the callback to handle the click - it will be called with the alarm log entry
        chart_div_offset: -50,          // give that space above the chart when scrolling to it
        chart_div_id_prefix: 'chart_',  // the chart DIV IDs have this prefix (they should be NETDATA.name2id(chart.id))
        chart_div_animation_duration: 0,// the duration of the animation while scrolling to a chart

        ms_penalty: 0,                  // the time penalty of the next alarm
        ms_between_notifications: 500,  // firefox moves the alarms off-screen (above, outside the top of the screen)
                                        // if alarms are shown faster than: one per 500ms

        notifications: false,           // when true, the browser supports notifications (may not be granted though)
        last_notification_id: 0,        // the id of the last alarm_log we have raised an alarm for
        first_notification_id: 0,       // the id of the first alarm_log entry for this session
                                        // this is used to prevent CLEAR notifications for past events
        // notifications_shown: [],

        server: null,                   // the server to connect to for fetching alarms
        current: null,                  // the list of raised alarms - updated in the background
        callback: null,                 // a callback function to call every time the list of raised alarms is refreshed

        notify: function(entry) {
            // console.log('alarm ' + entry.unique_id);

            if(entry.updated === true) {
                // console.log('alarm ' + entry.unique_id + ' has been updated by another alarm');
                return;
            }

            var value_string = entry.value_string;

            if(NETDATA.alarms.current !== null) {
                // get the current value_string
                var t = NETDATA.alarms.current.alarms[entry.chart + '.' + entry.name];
                if(typeof t !== 'undefined' && entry.status === t.status && typeof t.value_string !== 'undefined')
                    value_string = t.value_string;
            }

            var name = entry.name.replace(/_/g, ' ');
            var status = entry.status.toLowerCase();
            var title = name + ' = ' + value_string.toString();
            var tag = entry.alarm_id;
            var icon = 'images/seo-performance-128.png';
            var interaction = false;
            var data = entry;
            var show = true;

            // console.log('alarm ' + entry.unique_id + ' ' + entry.chart + '.' + entry.name + ' is ' +  entry.status);

            switch(entry.status) {
                case 'REMOVED':
                    show = false;
                    break;

                case 'UNDEFINED':
                    return;

                case 'UNINITIALIZED':
                    return;

                case 'CLEAR':
                    if(entry.unique_id < NETDATA.alarms.first_notification_id) {
                        // console.log('alarm ' + entry.unique_id + ' is not current');
                        return;
                    }
                    if(entry.old_status === 'UNINITIALIZED' || entry.old_status === 'UNDEFINED') {
                        // console.log('alarm' + entry.unique_id + ' switch to CLEAR from ' + entry.old_status);
                        return;
                    }
                    if(entry.no_clear_notification === true) {
                        // console.log('alarm' + entry.unique_id + ' is CLEAR but has no_clear_notification flag');
                        return;
                    }
                    title = name + ' back to normal (' + value_string.toString() + ')';
                    icon = 'images/check-mark-2-128-green.png';
                    interaction = false;
                    break;

                case 'WARNING':
                    if(entry.old_status === 'CRITICAL')
                        status = 'demoted to ' + entry.status.toLowerCase();

                    icon = 'images/alert-128-orange.png';
                    interaction = false;
                    break;

                case 'CRITICAL':
                    if(entry.old_status === 'WARNING')
                        status = 'escalated to ' + entry.status.toLowerCase();
                    
                    icon = 'images/alert-128-red.png';
                    interaction = true;
                    break;

                default:
                    console.log('invalid alarm status ' + entry.status);
                    return;
            }

            /*
            // cleanup old notifications with the same alarm_id as this one
            // FIXME: it does not seem to work on any web browser!
            var len = NETDATA.alarms.notifications_shown.length;
            while(len--) {
                var n = NETDATA.alarms.notifications_shown[len];
                if(n.data.alarm_id === entry.alarm_id) {
                    console.log('removing old alarm ' + n.data.unique_id);

                    // close the notification
                    n.close.bind(n);

                    // remove it from the array
                    NETDATA.alarms.notifications_shown.splice(len, 1);
                    len = NETDATA.alarms.notifications_shown.length;
                }
            }
            */

            if(show === true) {

                setTimeout(function() {
                    // show this notification
                    // console.log('new notification: ' + title);
                    var n = new Notification(title, {
                        body: entry.hostname + ' - ' + entry.chart + ' (' + entry.family + ') - ' + status + ': ' + entry.info,
                        tag: tag,
                        requireInteraction: interaction,
                        icon: NETDATA.serverStatic + icon,
                        data: data
                    });

                    n.onclick = function(event) {
                        event.preventDefault();
                        NETDATA.alarms.onclick(event.target.data);
                    };

                    // console.log(n);
                    // NETDATA.alarms.notifications_shown.push(n);
                    // console.log(entry);
                }, NETDATA.alarms.ms_penalty);

                NETDATA.alarms.ms_penalty += NETDATA.alarms.ms_between_notifications;
            }
        },

        scrollToChart: function(chart_id) {
            if(typeof chart_id === 'string') {
                var offset = $('#' + NETDATA.alarms.chart_div_id_prefix + NETDATA.name2id(chart_id)).offset();
                if(typeof offset !== 'undefined') {
                    $('html, body').animate({ scrollTop: offset.top + NETDATA.alarms.chart_div_offset }, NETDATA.alarms.chart_div_animation_duration);
                    return true;
                }
            }
            return false;
        },

        scrollToAlarm: function(alarm) {
            if(typeof alarm === 'object') {
                var ret = NETDATA.alarms.scrollToChart(alarm.chart);

                if(ret === true && NETDATA.options.page_is_visible === false)
                    window.focus();
                //    alert('netdata dashboard will now scroll to chart: ' + alarm.chart + '\n\nThis alarm opened to bring the browser window in front of the screen. Click on the dashboard to prevent it from appearing again.');
            }

        },

        notifyAll: function() {
            // console.log('FETCHING ALARM LOG');
            NETDATA.alarms.get_log(NETDATA.alarms.last_notification_id, function(data) {
                // console.log('ALARM LOG FETCHED');

                if(data === null || typeof data !== 'object') {
                    console.log('invalid alarms log response');
                    return;
                }

                if(data.length === 0) {
                    console.log('received empty alarm log');
                    return;
                }

                // console.log('received alarm log of ' + data.length + ' entries, from ' + data[data.length - 1].unique_id.toString() + ' to ' + data[0].unique_id.toString());

                data.sort(function(a, b) {
                    if(a.unique_id > b.unique_id) return -1;
                    if(a.unique_id < b.unique_id) return 1;
                    return 0;
                });

                NETDATA.alarms.ms_penalty = 0;

                var len = data.length;
                while(len--) {
                    if(data[len].unique_id > NETDATA.alarms.last_notification_id) {
                        NETDATA.alarms.notify(data[len]);
                    }
                    //else
                    //    console.log('ignoring alarm (older) with id ' + data[len].unique_id.toString());
                }

                NETDATA.alarms.last_notification_id = data[0].unique_id;
                NETDATA.localStorageSet('last_notification_id', NETDATA.alarms.last_notification_id, null);
                // console.log('last notification id = ' + NETDATA.alarms.last_notification_id);
            })
        },

        check_notifications: function() {
            // returns true if we should fire 1+ notifications

            if(NETDATA.alarms.notifications !== true) {
                // console.log('notifications not available');
                return false;
            }

            if(Notification.permission !== 'granted') {
                // console.log('notifications not granted');
                return false;
            }

            if(typeof NETDATA.alarms.current !== 'undefined' && typeof NETDATA.alarms.current.alarms === 'object') {
                // console.log('can do alarms: old id = ' + NETDATA.alarms.last_notification_id + ' new id = ' + NETDATA.alarms.current.latest_alarm_log_unique_id);

                if(NETDATA.alarms.current.latest_alarm_log_unique_id > NETDATA.alarms.last_notification_id) {
                    // console.log('new alarms detected');
                    return true;
                }
                //else console.log('no new alarms');
            }
            // else console.log('cannot process alarms');

            return false;
        },

        get: function(what, callback) {
            $.ajax({
                url: NETDATA.alarms.server + '/api/v1/alarms?' + what.toString(),
                async: true,
                cache: false,
                headers: {
                    'Cache-Control': 'no-cache, no-store',
                    'Pragma': 'no-cache'
                },
                xhrFields: { withCredentials: true } // required for the cookie
            })
                .done(function(data) {
                    if(NETDATA.alarms.first_notification_id === 0 && typeof data.latest_alarm_log_unique_id === 'number')
                        NETDATA.alarms.first_notification_id = data.latest_alarm_log_unique_id;

                    if(typeof callback === 'function')
                        return callback(data);
                })
                .fail(function() {
                    NETDATA.error(415, NETDATA.alarms.server);

                    if(typeof callback === 'function')
                        return callback(null);
                });
        },

        update_forever: function() {
            if(netdataShowAlarms !== true || netdataSnapshotData !== null)
                return;

            NETDATA.alarms.get('active', function(data) {
                if(data !== null) {
                    NETDATA.alarms.current = data;

                    if(NETDATA.alarms.check_notifications() === true) {
                        NETDATA.alarms.notifyAll();
                    }

                    if (typeof NETDATA.alarms.callback === 'function') {
                        NETDATA.alarms.callback(data);
                    }

                    // Health monitoring is disabled on this netdata
                    if(data.status === false) return;
                }

                setTimeout(NETDATA.alarms.update_forever, 10000);
            });
        },

        get_log: function(last_id, callback) {
            // console.log('fetching all log after ' + last_id.toString());
            $.ajax({
                url: NETDATA.alarms.server + '/api/v1/alarm_log?after=' + last_id.toString(),
                async: true,
                cache: false,
                headers: {
                    'Cache-Control': 'no-cache, no-store',
                    'Pragma': 'no-cache'
                },
                xhrFields: { withCredentials: true } // required for the cookie
            })
                .done(function(data) {
                    if(typeof callback === 'function')
                        return callback(data);
                })
                .fail(function() {
                    NETDATA.error(416, NETDATA.alarms.server);

                    if(typeof callback === 'function')
                        return callback(null);
                });
        },

        init: function() {
            NETDATA.alarms.server = NETDATA.fixHost(NETDATA.serverDefault);

            NETDATA.alarms.last_notification_id =
                NETDATA.localStorageGet('last_notification_id', NETDATA.alarms.last_notification_id, null);

            if(NETDATA.alarms.onclick === null)
                NETDATA.alarms.onclick = NETDATA.alarms.scrollToAlarm;

            if(netdataShowAlarms === true) {
                NETDATA.alarms.update_forever();
            
                if('Notification' in window) {
                    // console.log('notifications available');
                    NETDATA.alarms.notifications = true;

                    if(Notification.permission === 'default')
                        Notification.requestPermission();
                }
            }
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Registry of netdata hosts

    NETDATA.registry = {
        server: null,         // the netdata registry server
        person_guid: null,    // the unique ID of this browser / user
        machine_guid: null,   // the unique ID the netdata server that served dashboard.js
        hostname: 'unknown',  // the hostname of the netdata server that served dashboard.js
        machines: null,       // the user's other URLs
        machines_array: null, // the user's other URLs in an array
        person_urls: null,

        parsePersonUrls: function(person_urls) {
            // console.log(person_urls);
            NETDATA.registry.person_urls = person_urls;

            if(person_urls) {
                NETDATA.registry.machines = {};
                NETDATA.registry.machines_array = [];

                var apu = person_urls;
                var i = apu.length;
                while(i--) {
                    if(typeof NETDATA.registry.machines[apu[i][0]] === 'undefined') {
                        // console.log('adding: ' + apu[i][4] + ', ' + ((now - apu[i][2]) / 1000).toString());

                        var obj = {
                            guid: apu[i][0],
                            url: apu[i][1],
                            last_t: apu[i][2],
                            accesses: apu[i][3],
                            name: apu[i][4],
                            alternate_urls: []
                        };
                        obj.alternate_urls.push(apu[i][1]);

                        NETDATA.registry.machines[apu[i][0]] = obj;
                        NETDATA.registry.machines_array.push(obj);
                    }
                    else {
                        // console.log('appending: ' + apu[i][4] + ', ' + ((now - apu[i][2]) / 1000).toString());

                        var pu = NETDATA.registry.machines[apu[i][0]];
                        if(pu.last_t < apu[i][2]) {
                            pu.url = apu[i][1];
                            pu.last_t = apu[i][2];
                            pu.name = apu[i][4];
                        }
                        pu.accesses += apu[i][3];
                        pu.alternate_urls.push(apu[i][1]);
                    }
                }
            }

            if(typeof netdataRegistryCallback === 'function')
                netdataRegistryCallback(NETDATA.registry.machines_array);
        },

        init: function() {
            if(netdataRegistry !== true) return;

            NETDATA.registry.hello(NETDATA.serverDefault, function(data) {
                if(data) {
                    NETDATA.registry.server = data.registry;
                    NETDATA.registry.machine_guid = data.machine_guid;
                    NETDATA.registry.hostname = data.hostname;

                    NETDATA.registry.access(2, function (person_urls) {
                        NETDATA.registry.parsePersonUrls(person_urls);

                    });
                }
            });
        },

        hello: function(host, callback) {
            host = NETDATA.fixHost(host);

            // send HELLO to a netdata server:
            // 1. verifies the server is reachable
            // 2. responds with the registry URL, the machine GUID of this netdata server and its hostname
            $.ajax({
                    url: host + '/api/v1/registry?action=hello',
                    async: true,
                    cache: false,
                    headers: {
                        'Cache-Control': 'no-cache, no-store',
                        'Pragma': 'no-cache'
                    },
                    xhrFields: { withCredentials: true } // required for the cookie
                })
                .done(function(data) {
                    if(typeof data.status !== 'string' || data.status !== 'ok') {
                        NETDATA.error(408, host + ' response: ' + JSON.stringify(data));
                        data = null;
                    }

                    if(typeof callback === 'function')
                        return callback(data);
                })
                .fail(function() {
                    NETDATA.error(407, host);

                    if(typeof callback === 'function')
                        return callback(null);
                });
        },

        access: function(max_redirects, callback) {
            // send ACCESS to a netdata registry:
            // 1. it lets it know we are accessing a netdata server (its machine GUID and its URL)
            // 2. it responds with a list of netdata servers we know
            // the registry identifies us using a cookie it sets the first time we access it
            // the registry may respond with a redirect URL to send us to another registry
            $.ajax({
                    url: NETDATA.registry.server + '/api/v1/registry?action=access&machine=' + NETDATA.registry.machine_guid + '&name=' + encodeURIComponent(NETDATA.registry.hostname) + '&url=' + encodeURIComponent(NETDATA.serverDefault), // + '&visible_url=' + encodeURIComponent(document.location),
                    async: true,
                    cache: false,
                    headers: {
                        'Cache-Control': 'no-cache, no-store',
                        'Pragma': 'no-cache'
                    },
                    xhrFields: { withCredentials: true } // required for the cookie
                })
                .done(function(data) {
                    var redirect = null;
                    if(typeof data.registry === 'string')
                        redirect = data.registry;

                    if(typeof data.status !== 'string' || data.status !== 'ok') {
                        NETDATA.error(409, NETDATA.registry.server + ' responded with: ' + JSON.stringify(data));
                        data = null;
                    }

                    if(data === null) {
                        if(redirect !== null && max_redirects > 0) {
                            NETDATA.registry.server = redirect;
                            NETDATA.registry.access(max_redirects - 1, callback);
                        }
                        else {
                            if(typeof callback === 'function')
                                return callback(null);
                        }
                    }
                    else {
                        if(typeof data.person_guid === 'string')
                            NETDATA.registry.person_guid = data.person_guid;

                        if(typeof callback === 'function')
                            return callback(data.urls);
                    }
                })
                .fail(function() {
                    NETDATA.error(410, NETDATA.registry.server);

                    if(typeof callback === 'function')
                        return callback(null);
                });
        },

        delete: function(delete_url, callback) {
            // send DELETE to a netdata registry:
            $.ajax({
                url: NETDATA.registry.server + '/api/v1/registry?action=delete&machine=' + NETDATA.registry.machine_guid + '&name=' + encodeURIComponent(NETDATA.registry.hostname) + '&url=' + encodeURIComponent(NETDATA.serverDefault) + '&delete_url=' + encodeURIComponent(delete_url),
                async: true,
                cache: false,
                headers: {
                    'Cache-Control': 'no-cache, no-store',
                    'Pragma': 'no-cache'
                },
                xhrFields: { withCredentials: true } // required for the cookie
            })
                .done(function(data) {
                    if(typeof data.status !== 'string' || data.status !== 'ok') {
                        NETDATA.error(411, NETDATA.registry.server + ' responded with: ' + JSON.stringify(data));
                        data = null;
                    }

                    if(typeof callback === 'function')
                        return callback(data);
                })
                .fail(function() {
                    NETDATA.error(412, NETDATA.registry.server);

                    if(typeof callback === 'function')
                        return callback(null);
                });
        },

        search: function(machine_guid, callback) {
            // SEARCH for the URLs of a machine:
            $.ajax({
                url: NETDATA.registry.server + '/api/v1/registry?action=search&machine=' + NETDATA.registry.machine_guid + '&name=' + encodeURIComponent(NETDATA.registry.hostname) + '&url=' + encodeURIComponent(NETDATA.serverDefault) + '&for=' + machine_guid,
                async: true,
                cache: false,
                headers: {
                    'Cache-Control': 'no-cache, no-store',
                    'Pragma': 'no-cache'
                },
                xhrFields: { withCredentials: true } // required for the cookie
            })
                .done(function(data) {
                    if(typeof data.status !== 'string' || data.status !== 'ok') {
                        NETDATA.error(417, NETDATA.registry.server + ' responded with: ' + JSON.stringify(data));
                        data = null;
                    }

                    if(typeof callback === 'function')
                        return callback(data);
                })
                .fail(function() {
                    NETDATA.error(418, NETDATA.registry.server);

                    if(typeof callback === 'function')
                        return callback(null);
                });
        },

        switch: function(new_person_guid, callback) {
            // impersonate
            $.ajax({
                url: NETDATA.registry.server + '/api/v1/registry?action=switch&machine=' + NETDATA.registry.machine_guid + '&name=' + encodeURIComponent(NETDATA.registry.hostname) + '&url=' + encodeURIComponent(NETDATA.serverDefault) + '&to=' + new_person_guid,
                async: true,
                cache: false,
                headers: {
                    'Cache-Control': 'no-cache, no-store',
                    'Pragma': 'no-cache'
                },
                xhrFields: { withCredentials: true } // required for the cookie
            })
                .done(function(data) {
                    if(typeof data.status !== 'string' || data.status !== 'ok') {
                        NETDATA.error(413, NETDATA.registry.server + ' responded with: ' + JSON.stringify(data));
                        data = null;
                    }

                    if(typeof callback === 'function')
                        return callback(data);
                })
                .fail(function() {
                    NETDATA.error(414, NETDATA.registry.server);

                    if(typeof callback === 'function')
                        return callback(null);
                });
        }
    };

    // ----------------------------------------------------------------------------------------------------------------
    // Boot it!

    if(typeof netdataPrepCallback === 'function')
        netdataPrepCallback();

    NETDATA.errorReset();
    NETDATA.loadRequiredCSS(0);

    NETDATA._loadjQuery(function() {
        NETDATA.loadRequiredJs(0, function() {
            if(typeof $().emulateTransitionEnd !== 'function') {
                // bootstrap is not available
                NETDATA.options.current.show_help = false;
            }

            if(typeof netdataDontStart === 'undefined' || !netdataDontStart) {
                if(NETDATA.options.debug.main_loop === true)
                    console.log('starting chart refresh thread');

                NETDATA.start();
            }
        });
    });
})(window, document, (typeof jQuery === 'function')?jQuery:undefined);
