/**
 * Unobtrusive scripting adapter for jQuery
 *
 * Requires jQuery 1.4.4 or later.
 * https://github.com/rails/jquery-ujs

 * Uploading file using rails.js
 * =============================
 *
 * By default, browsers do not allow files to be uploaded via AJAX. As a result, if there are any non-blank file fields
 * in the remote form, this adapter aborts the AJAX submission and allows the form to submit through standard means.
 *
 * The `ajax:aborted:file` event allows you to bind your own handler to process the form submission however you wish.
 *
 * Ex:
 *     $('form').live('ajax:aborted:file', function(event, elements){
 *       // Implement own remote file-transfer handler here for non-blank file inputs passed in `elements`.
 *       // Returning false in this handler tells rails.js to disallow standard form submission
 *       return false;
 *     });
 *
 * The `ajax:aborted:file` event is fired when a file-type input is detected with a non-blank value.
 *
 * Third-party tools can use this hook to detect when an AJAX file upload is attempted, and then use
 * techniques like the iframe method to upload the file instead.
 *
 * Required fields in rails.js
 * ===========================
 *
 * If any blank required inputs (required="required") are detected in the remote form, the whole form submission
 * is canceled. Note that this is unlike file inputs, which still allow standard (non-AJAX) form submission.
 *
 * The `ajax:aborted:required` event allows you to bind your own handler to inform the user of blank required inputs.
 *
 * !! Note that Opera does not fire the form's submit event if there are blank required inputs, so this event may never
 *    get fired in Opera. This event is what causes other browsers to exhibit the same submit-aborting behavior.
 *
 * Ex:
 *     $('form').live('ajax:aborted:required', function(event, elements){
 *       // Returning false in this handler tells rails.js to submit the form anyway.
 *       // The blank required inputs are passed to this function in `elements`.
 *       return ! confirm("Would you like to submit the form with missing info?");
 *     });
 */

(function($) {
  // Shorthand to make it a little easier to call public rails functions from within rails.js
  var rails;

  $.rails = rails = {
    // Link elements bound by jquery-ujs
    linkClickSelector: 'a[data-confirm], a[data-method], a[data-remote]',

    // Form elements bound by jquery-ujs
    formSubmitSelector: 'form',

    // Form input elements bound by jquery-ujs
    formInputClickSelector: 'form input[type=submit], form input[type=image], form button[type=submit], form button:not([type])',

    // Form input elements disabled during form submission
    disableSelector: 'input[data-disable-with], button[data-disable-with], textarea[data-disable-with]',

    // Form input elements re-enabled after form submission
    enableSelector: 'input[data-disable-with]:disabled, button[data-disable-with]:disabled, textarea[data-disable-with]:disabled',

    // Form required input elements
    requiredInputSelector: 'input[name][required],textarea[name][required]',

    // Form file input elements
    fileInputSelector: 'input:file',

    // Make sure that every Ajax request sends the CSRF token
    CSRFProtection: function(xhr) {
      var token = $('meta[name="csrf-token"]').attr('content');
      if (token) xhr.setRequestHeader('X-CSRF-Token', token);
    },

    // Triggers an event on an element and returns false if the event result is false
    fire: function(obj, name, data) {
      var event = $.Event(name);
      obj.trigger(event, data);
      return event.result !== false;
    },

    // Submits "remote" forms and links with ajax
    handleRemote: function(element) {
      var method, url, data,
        dataType = element.data('type') || ($.ajaxSettings && $.ajaxSettings.dataType);

      if (rails.fire(element, 'ajax:before')) {

        if (element.is('form')) {
          method = element.attr('method');
          url = element.attr('action');
          data = element.serializeArray();
          // memoized value from clicked submit button
          var button = element.data('ujs:submit-button');
          if (button) {
            data.push(button);
            element.data('ujs:submit-button', null);
          }
        } else {
          method = element.data('method');
          url = element.attr('href');
          data = null;
        }

        $.ajax({
          url: url, type: method || 'GET', data: data, dataType: dataType,
          // stopping the "ajax:beforeSend" event will cancel the ajax request
          beforeSend: function(xhr, settings) {
            if (settings.dataType === undefined) {
              xhr.setRequestHeader('accept', '*/*;q=0.5, ' + settings.accepts.script);
            }
            return rails.fire(element, 'ajax:beforeSend', [xhr, settings]);
          },
          success: function(data, status, xhr) {
            element.trigger('ajax:success', [data, status, xhr]);
          },
          complete: function(xhr, status) {
            element.trigger('ajax:complete', [xhr, status]);
          },
          error: function(xhr, status, error) {
            element.trigger('ajax:error', [xhr, status, error]);
          }
        });
      }
    },

    // Handles "data-method" on links such as:
    // <a href="/users/5" data-method="delete" rel="nofollow" data-confirm="Are you sure?">Delete</a>
    handleMethod: function(link) {
      var href = link.attr('href'),
        method = link.data('method'),
        csrf_token = $('meta[name=csrf-token]').attr('content'),
        csrf_param = $('meta[name=csrf-param]').attr('content'),
        form = $('<form method="post" action="' + href + '"></form>'),
        metadata_input = '<input name="_method" value="' + method + '" type="hidden" />';

      if (csrf_param !== undefined && csrf_token !== undefined) {
        metadata_input += '<input name="' + csrf_param + '" value="' + csrf_token + '" type="hidden" />';
      }

      form.hide().append(metadata_input).appendTo('body');
      form.submit();
    },

    /* Disables form elements:
      - Caches element value in 'ujs:enable-with' data store
      - Replaces element text with value of 'data-disable-with' attribute
      - Adds disabled=disabled attribute
    */
    disableFormElements: function(form) {
      form.find(rails.disableSelector).each(function() {
        var element = $(this), method = element.is('button') ? 'html' : 'val';
        element.data('ujs:enable-with', element[method]());
        element[method](element.data('disable-with'));
        element.attr('disabled', 'disabled');
      });
    },

    /* Re-enables disabled form elements:
      - Replaces element text with cached value from 'ujs:enable-with' data store (created in `disableFormElements`)
      - Removes disabled attribute
    */
    enableFormElements: function(form) {
      form.find(rails.enableSelector).each(function() {
        var element = $(this), method = element.is('button') ? 'html' : 'val';
        if (element.data('ujs:enable-with')) element[method](element.data('ujs:enable-with'));
        element.removeAttr('disabled');
      });
    },

    // If message provided in 'data-confirm' attribute, fires `confirm` event and returns result of confirm dialog.
    // Attaching a handler to the element's `confirm` event that returns false cancels the confirm dialog.
    allowAction: function(element) {
      var message = element.data('confirm');
      return !message || (rails.fire(element, 'confirm') && confirm(message));
    },

    // Helper function which checks for blank inputs in a form that match the specified CSS selector
    blankInputs: function(form, specifiedSelector, nonBlank) {
      var inputs = $(), input,
        selector = specifiedSelector || 'input,textarea';
      form.find(selector).each(function() {
        input = $(this);
        // Collect non-blank inputs if nonBlank option is true, otherwise, collect blank inputs
        if (nonBlank ? input.val() : !input.val()) {
          inputs = inputs.add(input);
        }
      });
      return inputs.length ? inputs : false;
    },

    // Helper function which checks for non-blank inputs in a form that match the specified CSS selector
    nonBlankInputs: function(form, specifiedSelector) {
      return rails.blankInputs(form, specifiedSelector, true); // true specifies nonBlank
    },

    // Helper function, needed to provide consistent behavior in IE
    stopEverything: function(e) {
      e.stopImmediatePropagation();
      return false;
    },

    // find all the submit events directly bound to the form and
    // manually invoke them. If anyone returns false then stop the loop
    callFormSubmitBindings: function(form) {
      var events = form.data('events'), continuePropagation = true;
      if (events !== undefined && events['submit'] !== undefined) {
        $.each(events['submit'], function(i, obj){
          if (typeof obj.handler === 'function') return continuePropagation = obj.handler(obj.data);
        });
      }
      return continuePropagation;
    }
  };

  // ajaxPrefilter is a jQuery 1.5 feature
  if ('ajaxPrefilter' in $) {
    $.ajaxPrefilter(function(options, originalOptions, xhr){ rails.CSRFProtection(xhr); });
  } else {
    $(document).ajaxSend(function(e, xhr){ rails.CSRFProtection(xhr); });
  }

  $(rails.linkClickSelector).live('click.rails', function(e) {
    var link = $(this);
    if (!rails.allowAction(link)) return rails.stopEverything(e);

    if (link.data('remote') !== undefined) {
      rails.handleRemote(link);
      return false;
    } else if (link.data('method')) {
      rails.handleMethod(link);
      return false;
    }
  });

  $(rails.formSubmitSelector).live('submit.rails', function(e) {
    var form = $(this),
      remote = form.data('remote') !== undefined,
      blankRequiredInputs = rails.blankInputs(form, rails.requiredInputSelector),
      nonBlankFileInputs = rails.nonBlankInputs(form, rails.fileInputSelector);

    if (!rails.allowAction(form)) return rails.stopEverything(e);

    // skip other logic when required values are missing or file upload is present
    if (blankRequiredInputs && rails.fire(form, 'ajax:aborted:required', [blankRequiredInputs])) {
      return !remote;
    }

    if (remote) {
      if (nonBlankFileInputs) {
        return rails.fire(form, 'ajax:aborted:file', [nonBlankFileInputs]);
      }

      // If browser does not support submit bubbling, then this live-binding will be called before direct
      // bindings. Therefore, we should directly call any direct bindings before remotely submitting form.
      if (!$.support.submitBubbles && rails.callFormSubmitBindings(form) === false) return rails.stopEverything(e);

      rails.handleRemote(form);
      return false;
    } else {
      // slight timeout so that the submit button gets properly serialized
      setTimeout(function(){ rails.disableFormElements(form); }, 13);
    }
  });

  $(rails.formInputClickSelector).live('click.rails', function(event) {
    var button = $(this);

    if (!rails.allowAction(button)) return rails.stopEverything(event);

    // register the pressed submit button
    var name = button.attr('name'),
      data = name ? {name:name, value:button.val()} : null;

    button.closest('form').data('ujs:submit-button', data);
  });

  $(rails.formSubmitSelector).live('ajax:beforeSend.rails', function(event) {
    if (this == event.target) rails.disableFormElements($(this));
  });

  $(rails.formSubmitSelector).live('ajax:complete.rails', function(event) {
    if (this == event.target) rails.enableFormElements($(this));
  });

})( jQuery );