/**
 * @file
 * Drupal Image plugin.
 *
 * This alters the existing CKEditor image2 widget plugin to:
 * - require a data-entity-type and a data-entity-uuid attribute (which Drupal
 *   uses to track where images are being used)
 * - use a Drupal-native dialog (that is in fact just an alterable Drupal form
 *   like any other) instead of CKEditor's own dialogs.
 *
 * @see \Drupal\editor\Form\EditorImageDialog
 *
 * @ignore
 */

(function($, Drupal, CKEDITOR) {
  /**
   * Gets the focused widget, if of the type specific for this plugin.
   *
   * @param {CKEDITOR.editor} editor
   *   A CKEditor instance.
   *
   * @return {?CKEDITOR.plugins.widget}
   *   The focused image2 widget instance, or null.
   */
  function getFocusedWidget(editor) {
    const widget = editor.widgets.focused;

    if (widget && widget.name === 'image') {
      return widget;
    }

    return null;
  }

  /**
   * Integrates the drupalimage widget with the drupallink plugin.
   *
   * Makes images linkable.
   *
   * @param {CKEDITOR.editor} editor
   *   A CKEditor instance.
   */
  function linkCommandIntegrator(editor) {
    // Nothing to integrate with if the drupallink plugin is not loaded.
    if (!editor.plugins.drupallink) {
      return;
    }

    CKEDITOR.plugins.drupallink.registerLinkableWidget('image');

    // Override default behaviour of 'drupalunlink' command.
    editor.getCommand('drupalunlink').on('exec', function(evt) {
      const widget = getFocusedWidget(editor);

      // Override 'drupalunlink' only when link truly belongs to the widget. If
      // wrapped inline widget in a link, let default unlink work.
      // @see https://dev.ckeditor.com/ticket/11814
      if (!widget || !widget.parts.link) {
        return;
      }

      widget.setData('link', null);

      // Selection (which is fake) may not change if unlinked image in focused
      // widget, i.e. if captioned image. Let's refresh command state manually
      // here.
      this.refresh(editor, editor.elementPath());

      evt.cancel();
    });

    // Override default refresh of 'drupalunlink' command.
    editor.getCommand('drupalunlink').on('refresh', function(evt) {
      const widget = getFocusedWidget(editor);

      if (!widget) {
        return;
      }

      // Note that widget may be wrapped in a link, which
      // does not belong to that widget (#11814).
      this.setState(
        widget.data.link || widget.wrapper.getAscendant('a')
          ? CKEDITOR.TRISTATE_OFF
          : CKEDITOR.TRISTATE_DISABLED,
      );

      evt.cancel();
    });
  }

  CKEDITOR.plugins.add('drupalimage', {
    requires: 'image2',
    icons: 'drupalimage',
    hidpi: true,

    beforeInit(editor) {
      // Override the image2 widget definition to require and handle the
      // additional data-entity-type and data-entity-uuid attributes.
      editor.on('widgetDefinition', event => {
        const widgetDefinition = event.data;
        if (widgetDefinition.name !== 'image') {
          return;
        }

        // First, convert requiredContent & allowedContent from the string
        // format that image2 uses for both to formats that are better suited
        // for extending, so that both this basic drupalimage plugin and Drupal
        // modules can easily extend it.
        // @see http://docs.ckeditor.com/#!/api/CKEDITOR.filter.allowedContentRules
        // Mapped from image2's allowedContent. Unlike image2, we don't allow
        // <figure>, <figcaption>, <div> or <p>  in our downcast, so we omit
        // those. For the <img> tag, we list all attributes it lists, but omit
        // the classes, because the listed classes are for alignment, and for
        // alignment we use the data-align attribute.
        widgetDefinition.allowedContent = {
          img: {
            attributes: {
              '!src': true,
              '!alt': true,
              width: true,
              height: true,
            },
            classes: {},
          },
        };
        // Mapped from image2's requiredContent: "img[src,alt]". This does not
        // use the object format unlike above, but a CKEDITOR.style instance,
        // because requiredContent does not support the object format.
        // @see https://www.drupal.org/node/2585173#comment-10456981
        widgetDefinition.requiredContent = new CKEDITOR.style({
          element: 'img',
          attributes: {
            src: '',
            alt: '',
          },
        });

        // Extend requiredContent & allowedContent.
        // CKEDITOR.style is an immutable object: we cannot modify its
        // definition to extend requiredContent. Hence we get the definition,
        // modify it, and pass it to a new CKEDITOR.style instance.
        const requiredContent = widgetDefinition.requiredContent.getDefinition();
        requiredContent.attributes['data-entity-type'] = '';
        requiredContent.attributes['data-entity-uuid'] = '';
        widgetDefinition.requiredContent = new CKEDITOR.style(requiredContent);
        widgetDefinition.allowedContent.img.attributes[
          '!data-entity-type'
        ] = true;
        widgetDefinition.allowedContent.img.attributes[
          '!data-entity-uuid'
        ] = true;

        // Override downcast(): since we only accept <img> in our upcast method,
        // the element is already correct. We only need to update the element's
        // data-entity-uuid attribute.
        widgetDefinition.downcast = function(element) {
          element.attributes['data-entity-type'] = this.data[
            'data-entity-type'
          ];
          element.attributes['data-entity-uuid'] = this.data[
            'data-entity-uuid'
          ];
        };

        // We want to upcast <img> elements to a DOM structure required by the
        // image2 widget; we only accept an <img> tag, and that <img> tag MAY
        // have a data-entity-type and a data-entity-uuid attribute.
        widgetDefinition.upcast = function(element, data) {
          if (element.name !== 'img') {
            return;
          }
          // Don't initialize on pasted fake objects.
          if (element.attributes['data-cke-realelement']) {
            return;
          }

          // Parse the data-entity-type attribute.
          data['data-entity-type'] = element.attributes['data-entity-type'];
          // Parse the data-entity-uuid attribute.
          data['data-entity-uuid'] = element.attributes['data-entity-uuid'];

          return element;
        };

        // Overrides default implementation. Used to populate the "classes"
        // property of the widget's "data" property, which is used for the
        // "widget styles" functionality
        // (http://docs.ckeditor.com/#!/guide/dev_styles-section-widget-styles).
        // Is applied to whatever the main element of the widget is (<figure> or
        // <img>). The classes in image2_captionedClass are always added due to
        // a bug in CKEditor. In the case of drupalimage, we don't ever want to
        // add that class, because the widget template already contains it.
        // @see http://dev.ckeditor.com/ticket/13888
        // @see https://www.drupal.org/node/2268941
        const originalGetClasses = widgetDefinition.getClasses;
        widgetDefinition.getClasses = function() {
          const classes = originalGetClasses.call(this);
          const captionedClasses = (
            this.editor.config.image2_captionedClass || ''
          ).split(/\s+/);

          if (captionedClasses.length && classes) {
            for (let i = 0; i < captionedClasses.length; i++) {
              if (captionedClasses[i] in classes) {
                delete classes[captionedClasses[i]];
              }
            }
          }

          return classes;
        };

        // Protected; keys of the widget data to be sent to the Drupal dialog.
        // Keys in the hash are the keys for image2's data, values are the keys
        // that the Drupal dialog uses.
        widgetDefinition._mapDataToDialog = {
          src: 'src',
          alt: 'alt',
          width: 'width',
          height: 'height',
          'data-entity-type': 'data-entity-type',
          'data-entity-uuid': 'data-entity-uuid',
        };

        // Protected; transforms widget's data object to the format used by the
        // \Drupal\editor\Form\EditorImageDialog dialog, keeping only the data
        // listed in widgetDefinition._dataForDialog.
        widgetDefinition._dataToDialogValues = function(data) {
          const dialogValues = {};
          const map = widgetDefinition._mapDataToDialog;
          Object.keys(widgetDefinition._mapDataToDialog).forEach(key => {
            dialogValues[map[key]] = data[key];
          });
          return dialogValues;
        };

        // Protected; the inverse of _dataToDialogValues.
        widgetDefinition._dialogValuesToData = function(dialogReturnValues) {
          const data = {};
          const map = widgetDefinition._mapDataToDialog;
          Object.keys(widgetDefinition._mapDataToDialog).forEach(key => {
            if (dialogReturnValues.hasOwnProperty(map[key])) {
              data[key] = dialogReturnValues[map[key]];
            }
          });
          return data;
        };

        // Protected; creates Drupal dialog save callback.
        widgetDefinition._createDialogSaveCallback = function(editor, widget) {
          return function(dialogReturnValues) {
            const firstEdit = !widget.ready;

            // Dialog may have blurred the widget. Re-focus it first.
            if (!firstEdit) {
              widget.focus();
            }

            editor.fire('saveSnapshot');

            // Pass `true` so DocumentFragment will also be returned.
            const container = widget.wrapper.getParent(true);
            const image = widget.parts.image;

            // Set the updated widget data, after the necessary conversions from
            // the dialog's return values.
            // Note: on widget#setData this widget instance might be destroyed.
            const data = widgetDefinition._dialogValuesToData(
              dialogReturnValues.attributes,
            );
            widget.setData(data);

            // Retrieve the widget once again. It could've been destroyed
            // when shifting state, so might deal with a new instance.
            widget = editor.widgets.getByElement(image);

            // It's first edit, just after widget instance creation, but before
            // it was inserted into DOM. So we need to retrieve the widget
            // wrapper from inside the DocumentFragment which we cached above
            // and finalize other things (like ready event and flag).
            if (firstEdit) {
              editor.widgets.finalizeCreation(container);
            }

            setTimeout(() => {
              // (Re-)focus the widget.
              widget.focus();
              // Save snapshot for undo support.
              editor.fire('saveSnapshot');
            });

            return widget;
          };
        };

        const originalInit = widgetDefinition.init;
        widgetDefinition.init = function() {
          originalInit.call(this);

          // Update data.link object with attributes if the link has been
          // discovered.
          // @see plugins/image2/plugin.js/init() in CKEditor; this is similar.
          if (this.parts.link) {
            this.setData(
              'link',
              CKEDITOR.plugins.image2.getLinkAttributesParser()(
                editor,
                this.parts.link,
              ),
            );
          }
        };
      });

      // Add a widget#edit listener to every instance of image2 widget in order
      // to handle its editing with a Drupal-native dialog.
      // This includes also a case just after the image was created
      // and dialog should be opened for it for the first time.
      editor.widgets.on('instanceCreated', event => {
        const widget = event.data;

        if (widget.name !== 'image') {
          return;
        }

        widget.on('edit', event => {
          // Cancel edit event to break image2's dialog binding
          // (and also to prevent automatic insertion before opening dialog).
          event.cancel();

          // Open drupalimage dialog.
          editor.execCommand('editdrupalimage', {
            existingValues: widget.definition._dataToDialogValues(widget.data),
            saveCallback: widget.definition._createDialogSaveCallback(
              editor,
              widget,
            ),
            // Drupal.t() will not work inside CKEditor plugins because CKEditor
            // loads the JavaScript file instead of Drupal. Pull translated
            // strings from the plugin settings that are translated server-side.
            dialogTitle: widget.data.src
              ? editor.config.drupalImage_dialogTitleEdit
              : editor.config.drupalImage_dialogTitleAdd,
          });
        });
      });

      // Register the "editdrupalimage" command, which essentially just replaces
      // the "image" command's CKEditor dialog with a Drupal-native dialog.
      editor.addCommand('editdrupalimage', {
        allowedContent:
          'img[alt,!src,width,height,!data-entity-type,!data-entity-uuid]',
        requiredContent: 'img[alt,src,data-entity-type,data-entity-uuid]',
        modes: { wysiwyg: 1 },
        canUndo: true,
        exec(editor, data) {
          const dialogSettings = {
            title: data.dialogTitle,
            dialogClass: 'editor-image-dialog',
          };
          Drupal.ckeditor.openDialog(
            editor,
            Drupal.url(`editor/dialog/image/${editor.config.drupal.format}`),
            data.existingValues,
            data.saveCallback,
            dialogSettings,
          );
        },
      });

      // Register the toolbar button.
      if (editor.ui.addButton) {
        editor.ui.addButton('DrupalImage', {
          label: Drupal.t('Image'),
          // Note that we use the original image2 command!
          command: 'image',
        });
      }
    },

    afterInit(editor) {
      linkCommandIntegrator(editor);
    },
  });

  // Override image2's integration with the official CKEditor link plugin:
  // integrate with the drupallink plugin instead.
  CKEDITOR.plugins.image2.getLinkAttributesParser = function() {
    return CKEDITOR.plugins.drupallink.parseLinkAttributes;
  };
  CKEDITOR.plugins.image2.getLinkAttributesGetter = function() {
    return CKEDITOR.plugins.drupallink.getLinkAttributes;
  };

  // Expose an API for other plugins to interact with drupalimage widgets.
  CKEDITOR.plugins.drupalimage = {
    getFocusedWidget,
  };
})(jQuery, Drupal, CKEDITOR);
