/**
 * @file
 * Handles AJAX fetching of views, including filter submission and response.
 */
(function ($) {

  /**
   * Attaches the AJAX behavior to exposed filter forms and key views links.
   */
  Drupal.behaviors.ViewsAjaxView = {};
  Drupal.behaviors.ViewsAjaxView.attach = function() {
    if (Drupal.settings && Drupal.settings.views && Drupal.settings.views.ajaxViews) {
      $.each(Drupal.settings.views.ajaxViews, function(i, settings) {
        Drupal.views.instances[i] = new Drupal.views.ajaxView(settings);
      });
    }
  };

  Drupal.views = {};
  Drupal.views.instances = {};

  /**
   * JavaScript object for a certain view.
   */
  Drupal.views.ajaxView = function(settings) {
    var selector = '.view-dom-id-' + settings.view_dom_id;
    this.$view = $(selector);

    // Retrieve the path to use for views' ajax.
    var ajax_path = Drupal.settings.views.ajax_path;

    // If there are multiple views this might've ended up showing up multiple
    // times.
    if (ajax_path.constructor.toString().indexOf("Array") != -1) {
      ajax_path = ajax_path[0];
    }

    // Check if there are any GET parameters to send to views.
    var queryString = window.location.search || '';
    if (queryString !== '') {
      // Remove the question mark and Drupal path component if any.
      var queryString = queryString.slice(1).replace(/q=[^&]+&?|&?render=[^&]+/, '');
      if (queryString !== '') {
        // If there is a '?' in ajax_path, clean url are on and & should be
        // used to add parameters.
        queryString = ((/\?/.test(ajax_path)) ? '&' : '?') + queryString;
      }
    }

    this.element_settings = {
      url: ajax_path + queryString,
      submit: settings,
      setClick: true,
      event: 'click',
      selector: selector,
      progress: {
        type: 'throbber'
      }
    };

    this.settings = settings;

    // Add the ajax to exposed forms.
    this.$exposed_form = $('#views-exposed-form-' + settings.view_name.replace(/_/g, '-') + '-' + settings.view_display_id.replace(/_/g, '-'));
    this.$exposed_form.once(jQuery.proxy(this.attachExposedFormAjax, this));

    // Store Drupal.ajax objects here for all pager links.
    this.links = [];

    // Add the ajax to pagers.
    this.$view
      .once(jQuery.proxy(this.attachPagerAjax, this));

    // Add a trigger to update this view specifically. In order to trigger a
    // refresh use the following code.
    //
    // @code
    // jQuery('.view-name').trigger('RefreshView');
    // @endcode
    // Add a trigger to update this view specifically.
    var self_settings = this.element_settings;
    self_settings.event = 'RefreshView';
    this.refreshViewAjax = new Drupal.ajax(this.selector, this.$view, self_settings);
  };

  Drupal.views.ajaxView.prototype.attachExposedFormAjax = function() {
    var button = $('input[type=submit], button[type=submit], input[type=image]', this.$exposed_form);
    button = button[0];

    // Call the autocomplete submit before doing AJAX.
    $(button).click(function () {
      if (Drupal.autocompleteSubmit) {
        Drupal.autocompleteSubmit();
      }
    });

    this.exposedFormAjax = new Drupal.ajax($(button).attr('id'), button, this.element_settings);
  };

  /**
   * Attach the ajax behavior to each link.
   */
  Drupal.views.ajaxView.prototype.attachPagerAjax = function() {
    this.$view.find('ul.pager > li > a, th.views-field a, .attachment .views-summary a')
      .each(jQuery.proxy(this.attachPagerLinkAjax, this));
  };

  /**
   * Attach the ajax behavior to a singe link.
   */
  Drupal.views.ajaxView.prototype.attachPagerLinkAjax = function(id, link) {
    var $link = $(link);
    // Don't attach to pagers inside nested views.
    if ($link.closest('.view')[0] !== this.$view[0]) {
      return;
    }
    var viewData = {};
    var href = $link.attr('href');

    // Provide a default page if none has been set. This must be done
    // prior to merging with settings to avoid accidentally using the
    // page landed on instead of page 1.
    if (typeof(viewData.page) === 'undefined') {
      viewData.page = 0;
    }

    // Construct an object using the settings defaults and then overriding
    // with data specific to the link.
    $.extend(
    viewData,
    this.settings,
    Drupal.Views.parseQueryString(href),
    // Extract argument data from the URL.
    Drupal.Views.parseViewArgs(href, this.settings.view_base_path)
    );

    // For anchor tags, these will go to the target of the anchor rather
    // than the usual location.
    $.extend(viewData, Drupal.Views.parseViewArgs(href, this.settings.view_base_path));

    this.element_settings.submit = viewData;
    this.pagerAjax = new Drupal.ajax(false, $link, this.element_settings);
    this.links.push(this.pagerAjax);
  };

  Drupal.ajax.prototype.commands.viewsScrollTop = function (ajax, response, status) {
    // Scroll to the top of the view. This will allow users
    // to browse newly loaded content after e.g. clicking a pager
    // link.
    var offset = $(response.selector).offset();
    // We can't guarantee that the scrollable object should be
    // the body, as the view could be embedded in something
    // more complex such as a modal popup. Recurse up the DOM
    // and scroll the first element that has a non-zero top.
    var scrollTarget = response.selector;
    while ($(scrollTarget).scrollTop() == 0 && $(scrollTarget).parent()) {
      scrollTarget = $(scrollTarget).parent();
    }
    // Only scroll upward.
    if (offset.top - 10 < $(scrollTarget).scrollTop()) {
      $(scrollTarget).animate({scrollTop: (offset.top - 10)}, 500);
    }
  };

})(jQuery);
