(function ($, Modernizr, Drupal) {

"use strict";

/**
 * The collapsible details object represents a single collapsible details element.
 */
function CollapsibleDetails (node) {
  this.$node = $(node);
  this.$node.data('details', this);
  // Expand details if there are errors inside, or if it contains an
  // element that is targeted by the URI fragment identifier.
  var anchor = location.hash && location.hash !== '#' ? ', ' + location.hash : '';
  if (this.$node.find('.error' + anchor).length) {
    this.$node.attr('open', true);
  }
  // Initialize and setup the summary,
  this.setupSummary();
  // Initialize and setup the legend.
  this.setupLegend();
}

/**
 * Extend CollapsibleDetails function.
 */
$.extend(CollapsibleDetails, {
  /**
   * Holds references to instantiated CollapsibleDetails objects.
   */
  instances: []
});

/**
 * Extend CollapsibleDetails prototype.
 */
$.extend(CollapsibleDetails.prototype, {
  /**
   * Initialize and setup summary events and markup.
   */
  setupSummary: function () {
    this.$summary = $('<span class="summary"></span>');
    this.$node
      .on('summaryUpdated', $.proxy(this.onSummaryUpdated, this))
      .trigger('summaryUpdated');
  },
  /**
   * Initialize and setup legend markup.
   */
  setupLegend: function () {
    // Turn the summary into a clickable link.
    var $legend = this.$node.find('> summary');

    $('<span class="details-summary-prefix visually-hidden"></span>')
      .append(this.$node.attr('open') ? Drupal.t('Hide') : Drupal.t('Show'))
      .prependTo($legend)
      .after(document.createTextNode(' '));

    // .wrapInner() does not retain bound events.
    $('<a class="details-title"></a>')
      .attr('href', '#' + this.$node.attr('id'))
      .prepend($legend.contents())
      .appendTo($legend)
      .on('click', $.proxy(this.onLegendClick, this));
    $legend.append(this.$summary);
  },
  /**
   * Handle legend clicks
   */
  onLegendClick: function (e) {
    this.toggle();
    e.preventDefault();
  },
  /**
   * Update summary
   */
  onSummaryUpdated: function () {
    var text = $.trim(this.$node.drupalGetSummary());
    this.$summary.html(text ? ' (' + text + ')' : '');
  },
  /**
   * Toggle the visibility of a details element using smooth animations.
   */
  toggle: function () {
    var isOpen = !!this.$node.attr('open');
    var $summaryPrefix = this.$node.find('> summary span.details-summary-prefix');
    if (isOpen) {
      $summaryPrefix.html(Drupal.t('Show'));
    }
    else {
      $summaryPrefix.html(Drupal.t('Hide'));
    }
    this.$node.attr('open', !isOpen);
  }
});

Drupal.behaviors.collapse = {
  attach: function (context) {
    if (Modernizr.details) {
      return;
    }
    var $collapsibleDetails = $(context).find('details').once('collapse');
    if ($collapsibleDetails.length) {
      for (var i = 0; i < $collapsibleDetails.length; i++) {
        CollapsibleDetails.instances.push(new CollapsibleDetails($collapsibleDetails[i]));
      }
    }
  }
};

// Expose constructor in the public space.
Drupal.CollapsibleDetails = CollapsibleDetails;

})(jQuery, Modernizr, Drupal);