// $Id$

/**
 * Provides AJAX-like page updating via AHAH (Asynchronous HTML and HTTP).
 *
 * AHAH is a method of making a request via Javascript while viewing an HTML
 * page. The request returns a small chunk of HTML, which is then directly
 * injected into the page.
 *
 * Drupal uses this file to enhance form elements with #ahah[path] and
 * #ahah[wrapper] properties. If set, this file will automatically be included
 * to provide AHAH capabilities.
 */

/**
 * Attaches the ahah behavior to each ahah form element.
 */
Drupal.behaviors.ahah = function(context) {
  for (var base in Drupal.settings.ahah) {
    if (!$('#'+ base + '.ahah-processed').size()) {
      var element_settings = Drupal.settings.ahah[base];

      $(element_settings.selector).each(function() {
        element_settings.element = this;
        var ahah = new Drupal.ahah(base, element_settings);
      });

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

/**
 * AHAH object.
 */
Drupal.ahah = function(base, element_settings) {
  // Set the properties for this object.
  this.element = element_settings.element;
  this.selector = element_settings.selector;
  this.event = element_settings.event;
  this.url = element_settings.url;
  this.wrapper = '#'+ element_settings.wrapper;
  this.effect = element_settings.effect;
  this.method = element_settings.method;
  this.progress = element_settings.progress;
  this.button = element_settings.button || { };

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

  // Record the form action and target, needed for iFrame file uploads.
  var form = $(this.element).parents('form');
  this.form_action = form.attr('action');
  this.form_target = form.attr('target');
  this.form_encattr = form.attr('encattr');

  // Set the options for the ajaxSubmit function.
  // The 'this' variable will not persist inside of the options object.
  var ahah = this;
  var options = {
    url: ahah.url,
    data: ahah.button,
    beforeSubmit: function(form_values, element_settings, options) {
      return ahah.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 = Drupal.parseJson(response);
      }
      return ahah.success(response, status);
    },
    complete: function(response, status) {
      if (status == 'error') {
        return ahah.error(response.responseText);
      }
    },
    dataType: 'json',
    type: 'POST'
  };

  // Bind the ajaxSubmit function to the element event.
  $(element_settings.element).bind(element_settings.event, function() {
    $(element_settings.element).parents('form').ajaxSubmit(options);
    return false;
  });
};

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

  // Insert progressbar or throbber.
  if (this.progress.type == 'bar') {
    var progressBar = new Drupal.progressBar('ahah-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('ahah-progress ahah-progress-bar');
    this.progress.object = progressBar;
    $(this.element).after(this.progress.element);
  }
  else if (this.progress.type == 'throbber') {
    this.progress.element = $('<div class="ahah-progress ahah-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.ahah.prototype.success = function (response, status) {
  var wrapper = $(this.wrapper);
  var form = $(this.element).parents('form');
  // Manually insert HTML into the jQuery object, using $() directly crashes
  // Safari with long string lengths. http://dev.jquery.com/ticket/1152
  var new_content = $('<div></div>').html(response.data);

  // Restore the previous action and target to the form.
  form.attr('action', this.form_action);
  this.form_target ? form.attr('target', this.form_target) : form.removeAttr('target');
  this.form_encattr ? form.attr('target', this.form_encattr) : form.removeAttr('encattr');

  // 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);

  // Add the new content to the page.
  Drupal.freezeHeight();
  if (this.method == 'replace') {
    wrapper.empty().append(new_content);
  }
  else {
    wrapper[this.method](new_content);
  }

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

  // Determine what effect use and what content will receive the effect, then
  // show the new content. For browser compatibility, Safari is excluded from
  // using effects on table rows.
  if (($.browser.safari && $("tr.ahah-new-content", new_content).size() > 0)) {
    new_content.show();
  }
  else if ($('.ahah-new-content', new_content).size() > 0) {
    $('.ahah-new-content', new_content).hide();
    new_content.show();
    $(".ahah-new-content", new_content)[this.showEffect](this.showSpeed);
  }
  else if (this.showEffect != 'show') {
    new_content[this.showEffect](this.showSpeed);
  }

  // Attach all javascript behaviors to the new content, if it was successfully
  // added to the page, this if statement allows #ahah[wrapper] to be optional.
  if (new_content.parents('html').length > 0) {
    Drupal.attachBehaviors(new_content);
  }

  Drupal.unfreezeHeight();
};

/**
 * Handler for the form redirection error.
 */
Drupal.ahah.prototype.error = function (error) {
  alert(Drupal.t('An error occurred:\n\n@error', { '@error': error }));
  // Resore the previous action and target to the form.
  element.parent('form').attr( { action: this.form_action, target: this.form_target} );
  // 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('progess-disabled').attr('disabled', false);
};