/**
 * @file
 * Positioning extensions for dialogs.
 */

/**
 * Triggers when content inside a dialog changes.
 *
 * @event dialogContentResize
 */

(function ($, Drupal, drupalSettings, debounce, displace) {

  'use strict';

  // autoResize option will turn off resizable and draggable.
  drupalSettings.dialog = $.extend({autoResize: true, maxHeight: '95%'}, drupalSettings.dialog);

  /**
   * Resets the current options for positioning.
   *
   * This is used as a window resize and scroll callback to reposition the
   * jQuery UI dialog. Although not a built-in jQuery UI option, this can
   * be disabled by setting autoResize: false in the options array when creating
   * a new {@link Drupal.dialog}.
   *
   * @function Drupal.dialog~resetSize
   *
   * @param {jQuery.Event} event
   *
   * @fires event:dialogContentResize
   */
  function resetSize(event) {
    var positionOptions = ['width', 'height', 'minWidth', 'minHeight', 'maxHeight', 'maxWidth', 'position'];
    var adjustedOptions = {};
    var windowHeight = $(window).height();
    var option;
    var optionValue;
    var adjustedValue;
    for (var n = 0; n < positionOptions.length; n++) {
      option = positionOptions[n];
      optionValue = event.data.settings[option];
      if (optionValue) {
        // jQuery UI does not support percentages on heights, convert to pixels.
        if (typeof optionValue === 'string' && /%$/.test(optionValue) && /height/i.test(option)) {
          // Take offsets in account.
          windowHeight -= displace.offsets.top + displace.offsets.bottom;
          adjustedValue = parseInt(0.01 * parseInt(optionValue, 10) * windowHeight, 10);
          // Don't force the dialog to be bigger vertically than needed.
          if (option === 'height' && event.data.$element.parent().outerHeight() < adjustedValue) {
            adjustedValue = 'auto';
          }
          adjustedOptions[option] = adjustedValue;
        }
      }
    }
    // Offset the dialog center to be at the center of Drupal.displace.offsets.
    adjustedOptions = resetPosition(adjustedOptions);
    event.data.$element
      .dialog('option', adjustedOptions)
      .trigger('dialogContentResize');
  }

  /**
   * Position the dialog's center at the center of displace.offsets boundaries.
   *
   * @function Drupal.dialog~resetPosition
   *
   * @param {object} options
   *
   * @return {object}
   */
  function resetPosition(options) {
    var offsets = displace.offsets;
    var left = offsets.left - offsets.right;
    var top = offsets.top - offsets.bottom;

    var leftString = (left > 0 ? '+' : '-') + Math.abs(Math.round(left / 2)) + 'px';
    var topString = (top > 0 ? '+' : '-') + Math.abs(Math.round(top / 2)) + 'px';
    options.position = {
      my: 'center' + (left !== 0 ? leftString : '') + ' center' + (top !== 0 ? topString : ''),
      of: window
    };
    return options;
  }

  $(window).on({
    'dialog:aftercreate': function (event, dialog, $element, settings) {
      var autoResize = debounce(resetSize, 20);
      var eventData = {settings: settings, $element: $element};
      if (settings.autoResize === true || settings.autoResize === 'true') {
        $element
          .dialog('option', {resizable: false, draggable: false})
          .dialog('widget').css('position', 'fixed');
        $(window)
          .on('resize.dialogResize scroll.dialogResize', eventData, autoResize)
          .trigger('resize.dialogResize');
        $(document).on('drupalViewportOffsetChange', eventData, autoResize);
      }
    },
    'dialog:beforeclose': function (event, dialog, $element) {
      $(window).off('.dialogResize');
    }
  });

})(jQuery, Drupal, drupalSettings, Drupal.debounce, Drupal.displace);
