// $Id$
(function ($) {

/**
 * Provides AJAX page updating via jQuery $.ajax (Asynchronous JavaScript and XML).
 *
 * AJAX is a method of making a request via Javascript while viewing an HTML
 * page. The request returns an array of commands encoded in JSON, which is
 * then executed to make any changes that are necessary to the page.
 *
 * Drupal uses this file to enhance form elements with #ajax['path'] and
 * #ajax['wrapper'] properties. If set, this file will automatically be included
 * to provide AJAX capabilities.
 */

Drupal.ajax = Drupal.ajax || {};

/**
 * Attaches the AJAX behavior to each AJAX form element.
 */
Drupal.behaviors.AJAX = {
  attach: function (context, settings) {
    // Load all AJAX behaviors specified in the settings.
    for (var base in settings.ajax) {
      if (!$('#' + base + '.ajax-processed').length) {
        var element_settings = settings.ajax[base];

        $(element_settings.selector).each(function () {
          element_settings.element = this;
          Drupal.ajax[base] = new Drupal.ajax(base, this, element_settings);
        });

        $('#' + base).addClass('ajax-processed');
      }
    }

    // Bind AJAX behaviors to all items showing the class.
    $('.use-ajax:not(.ajax-processed)').addClass('ajax-processed').each(function () {
      var element_settings = {};

      // For anchor tags, these will go to the target of the anchor rather
      // than the usual location.
      if ($(this).attr('href')) {
        element_settings.url = $(this).attr('href');
        element_settings.event = 'click';
      }
      var base = $(this).attr('id');
      Drupal.ajax[base] = new Drupal.ajax(base, this, element_settings);
    });

    // This class means to submit the form to the action using AJAX.
    $('.use-ajax-submit:not(.ajax-processed)').addClass('ajax-processed').each(function () {
      var element_settings = {};

      // AJAX submits specified in this manner automatically submit to the
      // normal form action.
      element_settings.url = $(this.form).attr('action');
      // Form submit button clicks need to tell the form what was clicked so
      // it gets passed in the POST request.
      element_settings.setClick = true;
      // Form buttons use the 'click' event rather than mousedown.
      element_settings.event = 'click';
      // Clicked form buttons look better with the throbber than the progress bar.
      element_settings.progress = { 'type': 'throbber' };

      var base = $(this).attr('id');
      Drupal.ajax[base] = new Drupal.ajax(base, this, element_settings);
    });
  }
};

/**
 * AJAX object.
 *
 * All AJAX objects on a page are accessible through the global Drupal.ajax
 * object and are keyed by the submit button's ID. You can access them from
 * your module's JavaScript file to override properties or functions.
 *
 * For example, if your AJAX enabled button has the ID 'edit-submit', you can
 * redefine the function that is called to insert the new content like this
 * (inside a Drupal.behaviors attach block):
 * @code
 *    Drupal.behaviors.myCustomAJAXStuff = {
 *      attach: function (context, settings) {
 *        Drupal.ajax['edit-submit'].commands.insert = function (ajax, response, status) {
 *          new_content = $(response.data);
 *          $('#my-wrapper').append(new_content);
 *          alert('New content was appended to #my-wrapper');
 *        }
 *      }
 *    };
 * @endcode
 */
Drupal.ajax = function (base, element, element_settings) {
  var defaults = {
    url: 'system/ajax',
    event: 'mousedown',
    keypress: true,
    selector: '#' + base,
    effect: 'none',
    speed: 'slow',
    method: 'replaceWith',
    progress: {
      type: 'bar',
      message: 'Please wait...'
    },
    submit: {
      'js': true
    }
  };

  $.extend(this, defaults, element_settings);

  this.element = element;

  // Replacing 'nojs' with 'ajax' in the URL allows for an easy method to let
  // the server detect when it needs to degrade gracefully.
  this.url = element_settings.url.replace(/\/nojs(\/|$)/g, '/ajax$1');
  this.wrapper = '#' + element_settings.wrapper;

  // If there isn't a form, jQuery.ajax() will be used instead, allowing us to
  // bind AJAX to links as well.
  if (this.element.form) {
    this.form = $(this.element.form);
  }

  // Set the options for the ajaxSubmit function.
  // The 'this' variable will not persist inside of the options object.
  var ajax = this;
  var options = {
    url: ajax.url,
    data: ajax.submit,
    beforeSerialize: function (element_settings, options) {
      return ajax.beforeSerialize(element_settings, options);
    },
    beforeSubmit: function (form_values, element_settings, options) {
      ajax.ajaxing = true;
      return ajax.beforeSubmit(form_values, element_settings, options);
    },
    success: function (response, status) {
      // Sanity check for browser support (object expected).
      // When using iFrame uploads, responses must be returned as a string.
      if (typeof response == 'string') {
        response = $.parseJSON(response);
      }
      return ajax.success(response, status);
    },
    complete: function (response, status) {
      ajax.ajaxing = false;
      if (status == 'error' || status == 'parsererror') {
        return ajax.error(response, ajax.url);
      }
    },
    dataType: 'json',
    type: 'POST'
  };

  // Bind the ajaxSubmit function to the element event.
  $(this.element).bind(element_settings.event, function () {
    if (ajax.ajaxing) {
      return false;
    }

    try {
      if (ajax.form) {
        // If setClick is set, we must set this to ensure that the button's
        // value is passed.
        if (ajax.setClick) {
          // Mark the clicked button. 'form.clk' is a special variable for
          // ajaxSubmit that tells the system which element got clicked to
          // trigger the submit. Without it there would be no 'op' or
          // equivalent.
          ajax.form.clk = this.element;
        }

        ajax.form.ajaxSubmit(options);     
      }
      else {
        $.ajax(options);
      }
    }
    catch (e) {
      alert("An error occurred while attempting to process " + options.url + ": " + e.message);
    }

    return false;
  });

  // If necessary, enable keyboard submission so that AJAX behaviors
  // can be triggered through keyboard input as well as e.g. a mousedown
  // action.
  if (element_settings.keypress) {
    $(element_settings.element).keypress(function (event) {
      // Detect enter key.
      if (event.keyCode == 13) {
        $(element_settings.element).trigger(element_settings.event);
        return false;
      }
    });
  }
};

/**
 * Handler for the form serialization.
 *
 * Runs before the beforeSubmit() handler (see below), and unlike that one, runs
 * before field data is collected.
 */
Drupal.ajax.prototype.beforeSerialize = function (element, options) {
  // Allow detaching behaviors to update field values before collecting them.
  // This is only needed when field values are added to the POST data, so only
  // when there is a form such that this.form.ajaxSubmit() is used instead of
  // $.ajax(). When there is no form and $.ajax() is used, beforeSerialize()
  // isn't called, but don't rely on that: explicitly check this.form.
  if (this.form) {
    var settings = this.settings || Drupal.settings;
    Drupal.detachBehaviors(this.form, settings, 'serialize');
  }
};

/**
 * Handler for the form redirection submission.
 */
Drupal.ajax.prototype.beforeSubmit = function (form_values, element, options) {
  // Disable the element that received the change.
  $(this.element).addClass('progress-disabled').attr('disabled', true);

  // Prevent duplicate HTML ids in the returned markup.
  // @see drupal_html_id()
  $('[id]').each(function () {
    form_values.push({ name: 'ajax_html_ids[]', value: this.id });
  });

  // Insert progressbar or throbber.
  if (this.progress.type == 'bar') {
    var progressBar = new Drupal.progressBar('ajax-progress-' + this.element.id, eval(this.progress.update_callback), this.progress.method, eval(this.progress.error_callback));
    if (this.progress.message) {
      progressBar.setProgress(-1, this.progress.message);
    }
    if (this.progress.url) {
      progressBar.startMonitoring(this.progress.url, this.progress.interval || 1500);
    }
    this.progress.element = $(progressBar.element).addClass('ajax-progress ajax-progress-bar');
    this.progress.object = progressBar;
    $(this.element).after(this.progress.element);
  }
  else if (this.progress.type == 'throbber') {
    this.progress.element = $('<div class="ajax-progress ajax-progress-throbber"><div class="throbber">&nbsp;</div></div>');
    if (this.progress.message) {
      $('.throbber', this.progress.element).after('<div class="message">' + this.progress.message + '</div>');
    }
    $(this.element).after(this.progress.element);
  }
};

/**
 * Handler for the form redirection completion.
 */
Drupal.ajax.prototype.success = function (response, status) {
  // Remove the progress element.
  if (this.progress.element) {
    $(this.progress.element).remove();
  }
  if (this.progress.object) {
    this.progress.object.stopMonitoring();
  }
  $(this.element).removeClass('progress-disabled').attr('disabled', false);

  Drupal.freezeHeight();

  for (i in response) {
    if (response[i]['command'] && this.commands[response[i]['command']]) {
      this.commands[response[i]['command']](this, response[i], status);
    }
  }

  // Reattach behaviors, if they were detached in beforeSerialize(). The
  // attachBehaviors() called on the new content from processing the response
  // commands is not sufficient, because behaviors from the entire form need
  // to be reattached.
  if (this.form) {
    var settings = this.settings || Drupal.settings;
    Drupal.attachBehaviors(this.form, settings);
  }

  Drupal.unfreezeHeight();

  // Remove any response-specific settings so they don't get used on the next
  // call by mistake.
  this.settings = {};
};

/**
 * Build an effect object which tells us how to apply the effect when adding new HTML.
 */
Drupal.ajax.prototype.getEffect = function (response) {
  var type = response.effect || this.effect;
  var speed = response.speed || this.speed;

  var effect = {};
  if (type == 'none') {
    effect.showEffect = 'show';
    effect.hideEffect = 'hide';
    effect.showSpeed = '';
  }
  else if (type == 'fade') {
    effect.showEffect = 'fadeIn';
    effect.hideEffect = 'fadeOut';
    effect.showSpeed = speed;
  }
  else {
    effect.showEffect = type + 'Toggle';
    effect.hideEffect = type + 'Toggle';
    effect.showSpeed = speed;
  }

  return effect;
};

/**
 * Handler for the form redirection error.
 */
Drupal.ajax.prototype.error = function (response, uri) {
  alert(Drupal.ajaxError(response, uri));
  // Remove the progress element.
  if (this.progress.element) {
    $(this.progress.element).remove();
  }
  if (this.progress.object) {
    this.progress.object.stopMonitoring();
  }
  // Undo hide.
  $(this.wrapper).show();
  // Re-enable the element.
  $(this.element).removeClass('progress-disabled').attr('disabled', false);
  // Reattach behaviors, if they were detached in beforeSerialize().
  if (this.form) {
    var settings = response.settings || this.settings || Drupal.settings;
    Drupal.attachBehaviors(this.form, settings);
  }
};

/**
 * Provide a series of commands that the server can request the client perform.
 */
Drupal.ajax.prototype.commands = {
  /**
   * Command to insert new content into the DOM.
   */
  insert: function (ajax, response, status) {
    // Get information from the response. If it is not there, default to
    // our presets.
    var wrapper = response.selector ? $(response.selector) : $(ajax.wrapper);
    var method = response.method || ajax.method;
    var effect = ajax.getEffect(response);

    // Manually insert HTML into the jQuery object, using $() directly crashes
    // Safari with long string lengths. http://dev.jquery.com/ticket/3178
    var new_content = $('<div></div>').html(response.data);

    // If removing content from the wrapper, detach behaviors first.
    switch (method) {
      case 'html':
      case 'replaceWith':
      case 'replaceAll':
      case 'empty':
      case 'remove':
        var settings = response.settings || ajax.settings || Drupal.settings;
        Drupal.detachBehaviors(wrapper, settings);
    }

    // Add the new content to the page.
    wrapper[method](new_content);

    // Immediately hide the new content if we're using any effects.
    if (effect.showEffect != 'show') {
      new_content.hide();
    }

    // Determine which effect to use and what content will receive the
    // effect, then show the new content.
    if ($('.ajax-new-content', new_content).length > 0) {
      $('.ajax-new-content', new_content).hide();
      new_content.show();
      $('.ajax-new-content', new_content)[effect.showEffect](effect.showSpeed);
    }
    else if (effect.showEffect != 'show') {
      new_content[effect.showEffect](effect.showSpeed);
    }

    // Attach all JavaScript behaviors to the new content, if it was successfully
    // added to the page, this if statement allows #ajax['wrapper'] to be
    // optional.
    if (new_content.parents('html').length > 0) {
      // Apply any settings from the returned JSON if available.
      var settings = response.settings || ajax.settings || Drupal.settings;
      Drupal.attachBehaviors(new_content, settings);
    }
  },

  /**
   * Command to remove a chunk from the page.
   */
  remove: function (ajax, response, status) {
    var settings = response.settings || ajax.settings || Drupal.settings;
    Drupal.detachBehaviors($(response.selector), settings);
    $(response.selector).remove();
  },

  /**
   * Command to mark a chunk changed.
   */
  changed: function (ajax, response, status) {
    if (!$(response.selector).hasClass('ajax-changed')) {
      $(response.selector).addClass('ajax-changed');
      if (response.asterisk) {
        $(response.selector).find(response.asterisk).append(' <span class="ajax-changed">*</span> ');
      }
    }
  },

  /**
   * Command to provide an alert.
   */
  alert: function (ajax, response, status) {
    alert(response.text, response.title);
  },

  /**
   * Command to provide the jQuery css() function.
   */
  css: function (ajax, response, status) {
    $(response.selector).css(response.argument);
  },

  /**
   * Command to set the settings that will be used for other commands in this response.
   */
  settings: function (ajax, response, status) {
    if (response.merge) {
      $.extend(true, Drupal.settings, response.settings);
    }
    else {
      ajax.settings = response.settings;
    }
  },

  /**
   * Command to attach data using jQuery's data API.
   */
  data: function (ajax, response, status) {
    $(response.selector).data(response.name, response.value);
  },

  /**
   * Command to restripe a table.
   */
  restripe: function (ajax, response, status) {
    // :even and :odd are reversed because jQuery counts from 0 and
    // we count from 1, so we're out of sync.
    // Match immediate children of the parent element to allow nesting.
    $('> tbody > tr:visible, > tr:visible', $(response.selector))
      .removeClass('odd even')
      .filter(':even').addClass('odd').end()
      .filter(':odd').addClass('even');
  }
};

})(jQuery);