/**
 * @file
 * Defines the behavior of the Drupal administration toolbar.
 */

(function ($, Drupal, drupalSettings) {

  'use strict';

  // Merge run-time settings with the defaults.
  var options = $.extend(
    {
      breakpoints: {
        'toolbar.narrow': '',
        'toolbar.standard': '',
        'toolbar.wide': ''
      }
    },
    drupalSettings.toolbar,
    // Merge strings on top of drupalSettings so that they are not mutable.
    {
      strings: {
        horizontal: Drupal.t('Horizontal orientation'),
        vertical: Drupal.t('Vertical orientation')
      }
    }
  );

  /**
   * Registers tabs with the toolbar.
   *
   * The Drupal toolbar allows modules to register top-level tabs. These may
   * point directly to a resource or toggle the visibility of a tray.
   *
   * Modules register tabs with hook_toolbar().
   *
   * @type {Drupal~behavior}
   *
   * @prop {Drupal~behaviorAttach} attach
   *   Attaches the toolbar rendering functionality to the toolbar element.
   */
  Drupal.behaviors.toolbar = {
    attach: function (context) {
      // Verify that the user agent understands media queries. Complex admin
      // toolbar layouts require media query support.
      if (!window.matchMedia('only screen').matches) {
        return;
      }
      // Process the administrative toolbar.
      $(context).find('#toolbar-administration').once('toolbar').each(function () {

        // Establish the toolbar models and views.
        var model = Drupal.toolbar.models.toolbarModel = new Drupal.toolbar.ToolbarModel({
          locked: JSON.parse(localStorage.getItem('Drupal.toolbar.trayVerticalLocked')) || false,
          activeTab: document.getElementById(JSON.parse(localStorage.getItem('Drupal.toolbar.activeTabID')))
        });
        Drupal.toolbar.views.toolbarVisualView = new Drupal.toolbar.ToolbarVisualView({
          el: this,
          model: model,
          strings: options.strings
        });
        Drupal.toolbar.views.toolbarAuralView = new Drupal.toolbar.ToolbarAuralView({
          el: this,
          model: model,
          strings: options.strings
        });
        Drupal.toolbar.views.bodyVisualView = new Drupal.toolbar.BodyVisualView({
          el: this,
          model: model
        });

        // Render collapsible menus.
        var menuModel = Drupal.toolbar.models.menuModel = new Drupal.toolbar.MenuModel();
        Drupal.toolbar.views.menuVisualView = new Drupal.toolbar.MenuVisualView({
          el: $(this).find('.toolbar-menu-administration').get(0),
          model: menuModel,
          strings: options.strings
        });

        // Handle the resolution of Drupal.toolbar.setSubtrees.
        // This is handled with a deferred so that the function may be invoked
        // asynchronously.
        Drupal.toolbar.setSubtrees.done(function (subtrees) {
          menuModel.set('subtrees', subtrees);
          var theme = drupalSettings.ajaxPageState.theme;
          localStorage.setItem('Drupal.toolbar.subtrees.' + theme, JSON.stringify(subtrees));
          // Indicate on the toolbarModel that subtrees are now loaded.
          model.set('areSubtreesLoaded', true);
        });

        // Attach a listener to the configured media query breakpoints.
        for (var label in options.breakpoints) {
          if (options.breakpoints.hasOwnProperty(label)) {
            var mq = options.breakpoints[label];
            var mql = Drupal.toolbar.mql[label] = window.matchMedia(mq);
            // Curry the model and the label of the media query breakpoint to
            // the mediaQueryChangeHandler function.
            mql.addListener(Drupal.toolbar.mediaQueryChangeHandler.bind(null, model, label));
            // Fire the mediaQueryChangeHandler for each configured breakpoint
            // so that they process once.
            Drupal.toolbar.mediaQueryChangeHandler.call(null, model, label, mql);
          }
        }

        // Trigger an initial attempt to load menu subitems. This first attempt
        // is made after the media query handlers have had an opportunity to
        // process. The toolbar starts in the vertical orientation by default,
        // unless the viewport is wide enough to accommodate a horizontal
        // orientation. Thus we give the Toolbar a chance to determine if it
        // should be set to horizontal orientation before attempting to load
        // menu subtrees.
        Drupal.toolbar.views.toolbarVisualView.loadSubtrees();

        $(document)
          // Update the model when the viewport offset changes.
          .on('drupalViewportOffsetChange.toolbar', function (event, offsets) {
            model.set('offsets', offsets);
          });

        // Broadcast model changes to other modules.
        model
          .on('change:orientation', function (model, orientation) {
            $(document).trigger('drupalToolbarOrientationChange', orientation);
          })
          .on('change:activeTab', function (model, tab) {
            $(document).trigger('drupalToolbarTabChange', tab);
          })
          .on('change:activeTray', function (model, tray) {
            $(document).trigger('drupalToolbarTrayChange', tray);
          });

        // If the toolbar's orientation is horizontal and no active tab is
        // defined then show the tray of the first toolbar tab by default (but
        // not the first 'Home' toolbar tab).
        if (Drupal.toolbar.models.toolbarModel.get('orientation') === 'horizontal' && Drupal.toolbar.models.toolbarModel.get('activeTab') === null) {
          Drupal.toolbar.models.toolbarModel.set({
            activeTab: $('.toolbar-bar .toolbar-tab:not(.home-toolbar-tab) a').get(0)
          });
        }
      });
    }
  };

  /**
   * Toolbar methods of Backbone objects.
   *
   * @namespace
   */
  Drupal.toolbar = {

    /**
     * A hash of View instances.
     *
     * @type {object.<string, Backbone.View>}
     */
    views: {},

    /**
     * A hash of Model instances.
     *
     * @type {object.<string, Backbone.Model>}
     */
    models: {},

    /**
     * A hash of MediaQueryList objects tracked by the toolbar.
     *
     * @type {object.<string, object>}
     */
    mql: {},

    /**
     * Accepts a list of subtree menu elements.
     *
     * A deferred object that is resolved by an inlined JavaScript callback.
     *
     * @type {jQuery.Deferred}
     *
     * @see toolbar_subtrees_jsonp().
     */
    setSubtrees: new $.Deferred(),

    /**
     * Respond to configured narrow media query changes.
     *
     * @param {Drupal.toolbar.ToolbarModel} model
     *   A toolbar model
     * @param {string} label
     *   Media query label.
     * @param {object} mql
     *   A MediaQueryList object.
     */
    mediaQueryChangeHandler: function (model, label, mql) {
      switch (label) {
        case 'toolbar.narrow':
          model.set({
            isOriented: mql.matches,
            isTrayToggleVisible: false
          });
          // If the toolbar doesn't have an explicit orientation yet, or if the
          // narrow media query doesn't match then set the orientation to
          // vertical.
          if (!mql.matches || !model.get('orientation')) {
            model.set({orientation: 'vertical'}, {validate: true});
          }
          break;

        case 'toolbar.standard':
          model.set({
            isFixed: mql.matches
          });
          break;

        case 'toolbar.wide':
          model.set({
            orientation: ((mql.matches) ? 'horizontal' : 'vertical')
          }, {validate: true});
          // The tray orientation toggle visibility does not need to be
          // validated.
          model.set({
            isTrayToggleVisible: mql.matches
          });
          break;

        default:
          break;
      }
    }
  };

  /**
   * A toggle is an interactive element often bound to a click handler.
   *
   * @return {string}
   *   A string representing a DOM fragment.
   */
  Drupal.theme.toolbarOrientationToggle = function () {
    return '<div class="toolbar-toggle-orientation"><div class="toolbar-lining">' +
      '<button class="toolbar-icon" type="button"></button>' +
      '</div></div>';
  };

  /**
   * Ajax command to set the toolbar subtrees.
   *
   * @param {Drupal.Ajax} ajax
   *   {@link Drupal.Ajax} object created by {@link Drupal.ajax}.
   * @param {object} response
   *   JSON response from the Ajax request.
   * @param {number} [status]
   *   XMLHttpRequest status.
   */
  Drupal.AjaxCommands.prototype.setToolbarSubtrees = function (ajax, response, status) {
    Drupal.toolbar.setSubtrees.resolve(response.subtrees);
  };

}(jQuery, Drupal, drupalSettings));