/**
 * @file
 * Attaches behaviors for the Tour module's toolbar tab.
 */

(function($, Backbone, Drupal, document) {
  const queryString = decodeURI(window.location.search);

  /**
   * Attaches the tour's toolbar tab behavior.
   *
   * It uses the query string for:
   * - tour: When ?tour=1 is present, the tour will start automatically after
   *   the page has loaded.
   * - tips: Pass ?tips=class in the url to filter the available tips to the
   *   subset which match the given class.
   *
   * @example
   * http://example.com/foo?tour=1&tips=bar
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attach tour functionality on `tour` events.
   */
  Drupal.behaviors.tour = {
    attach(context) {
      $('body')
        .once('tour')
        .each(() => {
          const model = new Drupal.tour.models.StateModel();
          new Drupal.tour.views.ToggleTourView({
            el: $(context).find('#toolbar-tab-tour'),
            model,
          });

          model
            // Allow other scripts to respond to tour events.
            .on('change:isActive', (model, isActive) => {
              $(document).trigger(
                isActive ? 'drupalTourStarted' : 'drupalTourStopped',
              );
            })
            // Initialization: check whether a tour is available on the current
            // page.
            .set('tour', $(context).find('ol#tour'));

          // Start the tour immediately if toggled via query string.
          if (/tour=?/i.test(queryString)) {
            model.set('isActive', true);
          }
        });
    },
  };

  /**
   * @namespace
   */
  Drupal.tour = Drupal.tour || {
    /**
     * @namespace Drupal.tour.models
     */
    models: {},

    /**
     * @namespace Drupal.tour.views
     */
    views: {},
  };

  /**
   * Backbone Model for tours.
   *
   * @constructor
   *
   * @augments Backbone.Model
   */
  Drupal.tour.models.StateModel = Backbone.Model.extend(
    /** @lends Drupal.tour.models.StateModel# */ {
      /**
       * @type {object}
       */
      defaults: /** @lends Drupal.tour.models.StateModel# */ {
        /**
         * Indicates whether the Drupal root window has a tour.
         *
         * @type {Array}
         */
        tour: [],

        /**
         * Indicates whether the tour is currently running.
         *
         * @type {bool}
         */
        isActive: false,

        /**
         * Indicates which tour is the active one (necessary to cleanly stop).
         *
         * @type {Array}
         */
        activeTour: [],
      },
    },
  );

  Drupal.tour.views.ToggleTourView = Backbone.View.extend(
    /** @lends Drupal.tour.views.ToggleTourView# */ {
      /**
       * @type {object}
       */
      events: { click: 'onClick' },

      /**
       * Handles edit mode toggle interactions.
       *
       * @constructs
       *
       * @augments Backbone.View
       */
      initialize() {
        this.listenTo(this.model, 'change:tour change:isActive', this.render);
        this.listenTo(this.model, 'change:isActive', this.toggleTour);
      },

      /**
       * {@inheritdoc}
       *
       * @return {Drupal.tour.views.ToggleTourView}
       *   The `ToggleTourView` view.
       */
      render() {
        // Render the visibility.
        this.$el.toggleClass('hidden', this._getTour().length === 0);
        // Render the state.
        const isActive = this.model.get('isActive');
        this.$el
          .find('button')
          .toggleClass('is-active', isActive)
          .prop('aria-pressed', isActive);
        return this;
      },

      /**
       * Model change handler; starts or stops the tour.
       */
      toggleTour() {
        if (this.model.get('isActive')) {
          const $tour = this._getTour();
          this._removeIrrelevantTourItems($tour, this._getDocument());
          const that = this;
          const close = Drupal.t('Close');
          if ($tour.find('li').length) {
            $tour.joyride({
              autoStart: true,
              postRideCallback() {
                that.model.set('isActive', false);
              },
              // HTML segments for tip layout.
              template: {
                link: `<a href="#close" class="joyride-close-tip" aria-label="${close}">&times;</a>`,
                button:
                  '<a href="#" class="button button--primary joyride-next-tip"></a>',
              },
            });
            this.model.set({ isActive: true, activeTour: $tour });
          }
        } else {
          this.model.get('activeTour').joyride('destroy');
          this.model.set({ isActive: false, activeTour: [] });
        }
      },

      /**
       * Toolbar tab click event handler; toggles isActive.
       *
       * @param {jQuery.Event} event
       *   The click event.
       */
      onClick(event) {
        this.model.set('isActive', !this.model.get('isActive'));
        event.preventDefault();
        event.stopPropagation();
      },

      /**
       * Gets the tour.
       *
       * @return {jQuery}
       *   A jQuery element pointing to a `<ol>` containing tour items.
       */
      _getTour() {
        return this.model.get('tour');
      },

      /**
       * Gets the relevant document as a jQuery element.
       *
       * @return {jQuery}
       *   A jQuery element pointing to the document within which a tour would be
       *   started given the current state.
       */
      _getDocument() {
        return $(document);
      },

      /**
       * Removes tour items for elements that don't have matching page elements.
       *
       * Or that are explicitly filtered out via the 'tips' query string.
       *
       * @example
       * <caption>This will filter out tips that do not have a matching
       * page element or don't have the "bar" class.</caption>
       * http://example.com/foo?tips=bar
       *
       * @param {jQuery} $tour
       *   A jQuery element pointing to a `<ol>` containing tour items.
       * @param {jQuery} $document
       *   A jQuery element pointing to the document within which the elements
       *   should be sought.
       *
       * @see Drupal.tour.views.ToggleTourView#_getDocument
       */
      _removeIrrelevantTourItems($tour, $document) {
        let removals = false;
        const tips = /tips=([^&]+)/.exec(queryString);
        $tour.find('li').each(function() {
          const $this = $(this);
          const itemId = $this.attr('data-id');
          const itemClass = $this.attr('data-class');
          // If the query parameter 'tips' is set, remove all tips that don't
          // have the matching class.
          if (tips && !$(this).hasClass(tips[1])) {
            removals = true;
            $this.remove();
            return;
          }
          // Remove tip from the DOM if there is no corresponding page element.
          if (
            (!itemId && !itemClass) ||
            (itemId && $document.find(`#${itemId}`).length) ||
            (itemClass && $document.find(`.${itemClass}`).length)
          ) {
            return;
          }
          removals = true;
          $this.remove();
        });

        // If there were removals, we'll have to do some clean-up.
        if (removals) {
          const total = $tour.find('li').length;
          if (!total) {
            this.model.set({ tour: [] });
          }

          $tour
            .find('li')
            // Rebuild the progress data.
            .each(function(index) {
              const progress = Drupal.t('!tour_item of !total', {
                '!tour_item': index + 1,
                '!total': total,
              });
              $(this)
                .find('.tour-progress')
                .text(progress);
            })
            // Update the last item to have "End tour" as the button.
            .eq(-1)
            .attr('data-text', Drupal.t('End tour'));
        }
      },
    },
  );
})(jQuery, Backbone, Drupal, document);
