/**
 * @file
 * A Backbone View that provides the aural view of CKEditor toolbar
 * configuration.
 */

(function(Drupal, Backbone, $) {
  Drupal.ckeditor.AuralView = Backbone.View.extend(
    /** @lends Drupal.ckeditor.AuralView# */ {
      /**
       * @type {object}
       */
      events: {
        'click .ckeditor-buttons a': 'announceButtonHelp',
        'click .ckeditor-multiple-buttons a': 'announceSeparatorHelp',
        'focus .ckeditor-button a': 'onFocus',
        'focus .ckeditor-button-separator a': 'onFocus',
        'focus .ckeditor-toolbar-group': 'onFocus',
      },

      /**
       * Backbone View for CKEditor toolbar configuration; aural UX (output only).
       *
       * @constructs
       *
       * @augments Backbone.View
       */
      initialize() {
        // Announce the button and group positions when the model is no longer
        // dirty.
        this.listenTo(this.model, 'change:isDirty', this.announceMove);
      },

      /**
       * Calls announce on buttons and groups when their position is changed.
       *
       * @param {Drupal.ckeditor.ConfigurationModel} model
       *   The ckeditor configuration model.
       * @param {bool} isDirty
       *   A model attribute that indicates if the changed toolbar configuration
       *   has been stored or not.
       */
      announceMove(model, isDirty) {
        // Announce the position of a button or group after the model has been
        // updated.
        if (!isDirty) {
          const item = document.activeElement || null;
          if (item) {
            const $item = $(item);
            if ($item.hasClass('ckeditor-toolbar-group')) {
              this.announceButtonGroupPosition($item);
            } else if ($item.parent().hasClass('ckeditor-button')) {
              this.announceButtonPosition($item.parent());
            }
          }
        }
      },

      /**
       * Handles the focus event of elements in the active and available toolbars.
       *
       * @param {jQuery.Event} event
       *   The focus event that was triggered.
       */
      onFocus(event) {
        event.stopPropagation();

        const $originalTarget = $(event.target);
        const $currentTarget = $(event.currentTarget);
        const $parent = $currentTarget.parent();
        if (
          $parent.hasClass('ckeditor-button') ||
          $parent.hasClass('ckeditor-button-separator')
        ) {
          this.announceButtonPosition($currentTarget.parent());
        } else if (
          $originalTarget.attr('role') !== 'button' &&
          $currentTarget.hasClass('ckeditor-toolbar-group')
        ) {
          this.announceButtonGroupPosition($currentTarget);
        }
      },

      /**
       * Announces the current position of a button group.
       *
       * @param {jQuery} $group
       *   A jQuery set that contains an li element that wraps a group of buttons.
       */
      announceButtonGroupPosition($group) {
        const $groups = $group.parent().children();
        const $row = $group.closest('.ckeditor-row');
        const $rows = $row.parent().children();
        const position = $groups.index($group) + 1;
        const positionCount = $groups.not('.placeholder').length;
        const row = $rows.index($row) + 1;
        const rowCount = $rows.not('.placeholder').length;
        let text = Drupal.t(
          '@groupName button group in position @position of @positionCount in row @row of @rowCount.',
          {
            '@groupName': $group.attr(
              'data-drupal-ckeditor-toolbar-group-name',
            ),
            '@position': position,
            '@positionCount': positionCount,
            '@row': row,
            '@rowCount': rowCount,
          },
        );
        // If this position is the first in the last row then tell the user that
        // pressing the down arrow key will create a new row.
        if (position === 1 && row === rowCount) {
          text += '\n';
          text += Drupal.t('Press the down arrow key to create a new row.');
        }
        Drupal.announce(text, 'assertive');
      },

      /**
       * Announces current button position.
       *
       * @param {jQuery} $button
       *   A jQuery set that contains an li element that wraps a button.
       */
      announceButtonPosition($button) {
        const $row = $button.closest('.ckeditor-row');
        const $rows = $row.parent().children();
        const $buttons = $button.closest('.ckeditor-buttons').children();
        const $group = $button.closest('.ckeditor-toolbar-group');
        const $groups = $group.parent().children();
        const groupPosition = $groups.index($group) + 1;
        const groupPositionCount = $groups.not('.placeholder').length;
        const position = $buttons.index($button) + 1;
        const positionCount = $buttons.length;
        const row = $rows.index($row) + 1;
        const rowCount = $rows.not('.placeholder').length;
        // The name of the button separator is 'button separator' and its type
        // is 'separator', so we do not want to print the type of this item,
        // otherwise the UA will speak 'button separator separator'.
        const type =
          $button.attr('data-drupal-ckeditor-type') === 'separator'
            ? ''
            : Drupal.t('button');
        let text;
        // The button is located in the available button set.
        if ($button.closest('.ckeditor-toolbar-disabled').length > 0) {
          text = Drupal.t('@name @type.', {
            '@name': $button.children().attr('aria-label'),
            '@type': type,
          });
          text += `\n${Drupal.t('Press the down arrow key to activate.')}`;

          Drupal.announce(text, 'assertive');
        }
        // The button is in the active toolbar.
        else if ($group.not('.placeholder').length === 1) {
          text = Drupal.t(
            '@name @type in position @position of @positionCount in @groupName button group in row @row of @rowCount.',
            {
              '@name': $button.children().attr('aria-label'),
              '@type': type,
              '@position': position,
              '@positionCount': positionCount,
              '@groupName': $group.attr(
                'data-drupal-ckeditor-toolbar-group-name',
              ),
              '@row': row,
              '@rowCount': rowCount,
            },
          );
          // If this position is the first in the last row then tell the user that
          // pressing the down arrow key will create a new row.
          if (groupPosition === 1 && position === 1 && row === rowCount) {
            text += '\n';
            text += Drupal.t(
              'Press the down arrow key to create a new button group in a new row.',
            );
          }
          // If this position is the last one in this row then tell the user that
          // moving the button to the next group will create a new group.
          if (
            groupPosition === groupPositionCount &&
            position === positionCount
          ) {
            text += '\n';
            text += Drupal.t(
              'This is the last group. Move the button forward to create a new group.',
            );
          }
          Drupal.announce(text, 'assertive');
        }
      },

      /**
       * Provides help information when a button is clicked.
       *
       * @param {jQuery.Event} event
       *   The click event for the button click.
       */
      announceButtonHelp(event) {
        const $link = $(event.currentTarget);
        const $button = $link.parent();
        const enabled = $button.closest('.ckeditor-toolbar-active').length > 0;
        let message;

        if (enabled) {
          message = Drupal.t('The "@name" button is currently enabled.', {
            '@name': $link.attr('aria-label'),
          });
          message += `\n${Drupal.t(
            'Use the keyboard arrow keys to change the position of this button.',
          )}`;
          message += `\n${Drupal.t(
            'Press the up arrow key on the top row to disable the button.',
          )}`;
        } else {
          message = Drupal.t('The "@name" button is currently disabled.', {
            '@name': $link.attr('aria-label'),
          });
          message += `\n${Drupal.t(
            'Use the down arrow key to move this button into the active toolbar.',
          )}`;
        }
        Drupal.announce(message);
        event.preventDefault();
      },

      /**
       * Provides help information when a separator is clicked.
       *
       * @param {jQuery.Event} event
       *   The click event for the separator click.
       */
      announceSeparatorHelp(event) {
        const $link = $(event.currentTarget);
        const $button = $link.parent();
        const enabled = $button.closest('.ckeditor-toolbar-active').length > 0;
        let message;

        if (enabled) {
          message = Drupal.t('This @name is currently enabled.', {
            '@name': $link.attr('aria-label'),
          });
          message += `\n${Drupal.t(
            'Use the keyboard arrow keys to change the position of this separator.',
          )}`;
        } else {
          message = Drupal.t(
            'Separators are used to visually split individual buttons.',
          );
          message += `\n${Drupal.t('This @name is currently disabled.', {
            '@name': $link.attr('aria-label'),
          })}`;
          message += `\n${Drupal.t(
            'Use the down arrow key to move this separator into the active toolbar.',
          )}`;
          message += `\n${Drupal.t(
            'You may add multiple separators to each button group.',
          )}`;
        }
        Drupal.announce(message);
        event.preventDefault();
      },
    },
  );
})(Drupal, Backbone, jQuery);
