/*
Copyright (c) 2011-2013 @WalmartLabs

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/

;;
(function() {

/*global cloneInheritVars, createInheritVars, createRegistryWrapper, getValue, inheritVars */

//support zepto.forEach on jQuery
if (!$.fn.forEach) {
  $.fn.forEach = function(iterator, context) {
    $.fn.each.call(this, function(index) {
      iterator.call(context || this, this, index);
    });
  };
}

var viewNameAttributeName = 'data-view-name',
    viewCidAttributeName = 'data-view-cid',
    viewHelperAttributeName = 'data-view-helper';

//view instances
var viewsIndexedByCid = {};

var Thorax = this.Thorax = {
  VERSION: '2.0.0rc1',
  templatePathPrefix: '',
  templates: {},
  //view classes
  Views: {},
  //certain error prone pieces of code (on Android only it seems)
  //are wrapped in a try catch block, then trigger this handler in
  //the catch, with the name of the function or event that was
  //trying to be executed. Override this with a custom handler
  //to debug / log / etc
  onException: function(name, err) {
    throw err;
  }
};

Thorax.View = Backbone.View.extend({
  constructor: function() {
    var response = Backbone.View.apply(this, arguments);
    _.each(inheritVars, function(obj) {
      if (obj.ctor) {
        obj.ctor.call(this, response);
      }
    }, this);
    return response;
  },
  _configure: function(options) {
    var self = this;

    this._objectOptionsByCid = {};
    this._boundDataObjectsByCid = {};

    // Setup object event tracking
    _.each(inheritVars, function(obj) {
      self[obj.name] = [];
    });

    viewsIndexedByCid[this.cid] = this;
    this.children = {};
    this._renderCount = 0;

    //this.options is removed in Thorax.View, we merge passed
    //properties directly with the view and template context
    _.extend(this, options || {});

    // Setup helpers
    bindHelpers.call(this);

    //compile a string if it is set as this.template
    if (typeof this.template === 'string') {
      this.template = Handlebars.compile(this.template, {data: true});
    } else if (this.name && !this.template) {
      //fetch the template
      this.template = Thorax.Util.getTemplate(this.name, true);
    }

    _.each(inheritVars, function(obj) {
      if (obj.configure) {
        obj.configure.call(this);
      }
    }, this);
  },

  setElement : function() {
    var response = Backbone.View.prototype.setElement.apply(this, arguments);
    this.name && this.$el.attr(viewNameAttributeName, this.name);
    this.$el.attr(viewCidAttributeName, this.cid);
    return response;
  },

  _addChild: function(view) {
    this.children[view.cid] = view;
    if (!view.parent) {
      view.parent = this;
    }
    this.trigger('child', view);
    return view;
  },

  _removeChild: function(view) {
    delete this.children[view.cid];
    view.parent = null;
    return view;
  },

  destroy: function(options) {
    options = _.defaults(options || {}, {
      children: true
    });
    _.each(this._boundDataObjectsByCid, this.unbindDataObject, this);
    this.trigger('destroyed');
    delete viewsIndexedByCid[this.cid];
    _.each(this.children, function(child) {
      this._removeChild(child);
      if (options.children) {
        child.destroy();
      }
    }, this);
    if (this.parent) {
      this.parent._removeChild(this);
    }
    this.remove(); // Will call stopListening()
  },

  render: function(output) {
    this._previousHelpers = _.filter(this.children, function(child) { return child._helperOptions; });

    var children = {};
    _.each(this.children, function(child, key) {
      if (!child._helperOptions) {
        children[key] = child;
      }
    });
    this.children = children;

    if (typeof output === 'undefined' || (!_.isElement(output) && !Thorax.Util.is$(output) && !(output && output.el) && typeof output !== 'string' && typeof output !== 'function')) {
      if (!this.template) {
        //if the name was set after the view was created try one more time to fetch a template
        if (this.name) {
          this.template = Thorax.Util.getTemplate(this.name, true);
        }
        if (!this.template) {
          throw new Error('View ' + (this.name || this.cid) + '.render() was called with no content and no template set on the view.');
        }
      }
      output = this.renderTemplate(this.template);
    } else if (typeof output === 'function') {
      output = this.renderTemplate(output);
    }

    // Destroy any helpers that may be lingering
    _.each(this._previousHelpers, function(child) {
      child.destroy();
      child.parent = undefined;
    });
    this._previousHelpers = undefined;

    //accept a view, string, Handlebars.SafeString or DOM element
    this.html((output && output.el) || (output && output.string) || output);
    ++this._renderCount;
    this.trigger('rendered');
    return output;
  },

  context: function() {
    return (this.model && this.model.attributes) || {};
  },

  _getContext: function() {
    return _.extend({}, this, getValue(this, 'context') || {});
  },

  // Private variables in handlebars / options.data in template helpers
  _getData: function(data) {
    return {
      view: this,
      cid: _.uniqueId('t'),
      yield: function() {
        // fn is seeded by template helper passing context to data
        return data.fn && data.fn(data);
      }
    };
  },

  _getHelpers: function() {
    if (this.helpers) {
      return _.extend({}, Handlebars.helpers, this.helpers);
    } else {
      return Handlebars.helpers;
    }

  },

  renderTemplate: function(file, context, ignoreErrors) {
    var template;
    context = context || this._getContext();
    if (typeof file === 'function') {
      template = file;
    } else {
      template = Thorax.Util.getTemplate(file);
    }
    if (!template) {
      if (ignoreErrors) {
        return '';
      } else {
        throw new Error('Unable to find template ' + file);
      }
    } else {
      return template(context, {
        helpers: this._getHelpers(),
        data: this._getData(context)
      });
    }
  },

  ensureRendered: function() {
    !this._renderCount && this.render();
  },

  appendTo: function(el) {
    this.ensureRendered();
    $(el).append(this.el);
    this.trigger('ready', {target: this});
  },

  html: function(html) {

    function replaceHTML(view) {
      view.el.innerHTML = "";
      return view.$el.append(html);
    }

    if (typeof html === 'undefined') {
      return this.el.innerHTML;
    } else {
      // Event for IE element fixes
      this.trigger('before:append');
      var element;
      if (this.collection && this._objectOptionsByCid[this.collection.cid] && this._renderCount) {
        // preserve collection element if it was not created with {{collection}} helper
        var oldCollectionElement = this.getCollectionElement();
        element = replaceHTML(this);
        if (!oldCollectionElement.attr('data-view-cid')) {
          this.getCollectionElement().replaceWith(oldCollectionElement);
        }
      } else {
        element = replaceHTML(this);
      }
      this.trigger('append');
      return element;
    }
  },

  _anchorClick: function(event) {
    var target = $(event.currentTarget),
        href = target.attr('href');
    // Route anything that starts with # or / (excluding //domain urls)
    if (href && (href[0] === '#' || (href[0] === '/' && href[1] !== '/'))) {
      Backbone.history.navigate(href, {
        trigger: true
      });
      return false;
    }
    return true;
  }
});

Thorax.View.extend = function() {
  createInheritVars(this);

  var child = Backbone.View.extend.apply(this, arguments);
  child.__parent__ = this;

  resetInheritVars(child);

  return child;
};

createRegistryWrapper(Thorax.View, Thorax.Views);

function bindHelpers() {
  if (this.helpers) {
    _.each(this.helpers, function(helper, name) {
      var view = this;
      this.helpers[name] = function() {
        var args = _.toArray(arguments),
            options = _.last(args);
        options.context = this;
        return helper.apply(view, args);
      };
    }, this);
  }
}

//$(selector).view() helper
$.fn.view = function(options) {
  options = _.defaults(options || {}, {
    helper: true
  });
  var selector = '[' + viewCidAttributeName + ']';
  if (!options.helper) {
    selector += ':not([' + viewHelperAttributeName + '])';
  }
  var el = $(this).closest(selector);
  return (el && viewsIndexedByCid[el.attr(viewCidAttributeName)]) || false;
};

;;
/*global createRegistryWrapper:true, cloneEvents: true */
function createRegistryWrapper(klass, hash) {
  var $super = klass.extend;
  klass.extend = function() {
    var child = $super.apply(this, arguments);
    if (child.prototype.name) {
      hash[child.prototype.name] = child;
    }
    return child;
  };
}
function registryGet(object, type, name, ignoreErrors) {
  var target = object[type],
      value;
  if (name.indexOf('.') >= 0) {
    var bits = name.split(/\./);
    name = bits.pop();
    _.each(bits, function(key) {
      target = target[key];
    });
  }
  target && (value = target[name]);
  if (!value && !ignoreErrors) {
    throw new Error(type + ': ' + name + ' does not exist.');
  } else {
    return value;
  }
}

// getValue is used instead of _.result because we
// need an extra scope parameter, and will minify
// better than _.result
function getValue(object, prop, scope) {
  if (!(object && object[prop])) {
    return null;
  }
  return _.isFunction(object[prop])
    ? object[prop].call(scope || object)
    : object[prop];
}

var inheritVars = {};
function createInheritVars(self) {
  // Ensure that we have our static event objects
  _.each(inheritVars, function(obj) {
    if (!self[obj.name]) {
      self[obj.name] = [];
    }
  });
}
function resetInheritVars(self) {
  // Ensure that we have our static event objects
  _.each(inheritVars, function(obj) {
    self[obj.name] = [];
  });
}
function walkInheritTree(source, fieldName, isStatic, callback) {
  var tree = [];
  if (_.has(source, fieldName)) {
    tree.push(source);
  }
  var iterate = source;
  if (isStatic) {
    while (iterate = iterate.__parent__) {
      if (_.has(iterate, fieldName)) {
        tree.push(iterate);
      }
    }
  } else {
    iterate = iterate.constructor;
    while (iterate) {
      if (iterate.prototype && _.has(iterate.prototype, fieldName)) {
        tree.push(iterate.prototype);
      }
      iterate = iterate.__super__ && iterate.__super__.constructor;
    }
  }

  var i = tree.length;
  while (i--) {
    _.each(getValue(tree[i], fieldName, source), callback);
  }
}

function objectEvents(target, eventName, callback, context) {
  if (_.isObject(callback)) {
    var spec = inheritVars[eventName];
    if (spec && spec.event) {
      addEvents(target['_' + eventName + 'Events'], callback, context);
      return true;
    }
  }
}
function addEvents(target, source, context) {
  _.each(source, function(callback, eventName) {
    if (_.isArray(callback)) {
      _.each(callback, function(cb) {
        target.push([eventName, cb, context]);
      });
    } else {
      target.push([eventName, callback, context]);
    }
  });
}

function getOptionsData(options) {
  if (!options || !options.data) {
    throw new Error('Handlebars template compiled without data, use: Handlebars.compile(template, {data: true})');
  }
  return options.data;
}

// These whitelisted attributes will be the only ones passed
// from the options hash to Thorax.Util.tag
var htmlAttributesToCopy = ['id', 'className', 'tagName'];

// In helpers "tagName" or "tag" may be specified, as well
// as "class" or "className". Normalize to "tagName" and
// "className" to match the property names used by Backbone
// jQuery, etc. Special case for "className" in
// Thorax.Util.tag: will be rewritten as "class" in
// generated HTML.
function normalizeHTMLAttributeOptions(options) {
  if (options.tag) {
    options.tagName = options.tag;
    delete options.tag;
  }
  if (options['class']) {
    options.className = options['class'];
    delete options['class'];
  }
}

Thorax.Util = {
  getViewInstance: function(name, attributes) {
    attributes = attributes || {};
    if (typeof name === 'string') {
      var Klass = registryGet(Thorax, 'Views', name, false);
      return Klass.cid ? _.extend(Klass, attributes || {}) : new Klass(attributes);
    } else if (typeof name === 'function') {
      return new name(attributes);
    } else {
      return name;
    }
  },

  getTemplate: function(file, ignoreErrors) {
    //append the template path prefix if it is missing
    var pathPrefix = Thorax.templatePathPrefix,
        template;
    if (pathPrefix && file.substr(0, pathPrefix.length) !== pathPrefix) {
      file = pathPrefix + file;
    }

    // Without extension
    file = file.replace(/\.handlebars$/, '');
    template = Thorax.templates[file];
    if (!template) {
      // With extension
      file = file + '.handlebars';
      template = Thorax.templates[file];
    }

    if (template && typeof template === 'string') {
      template = Thorax.templates[file] = Handlebars.compile(template, {data: true});
    } else if (!template && !ignoreErrors) {
      throw new Error('templates: ' + file + ' does not exist.');
    }
    return template;
  },

  //'selector' is not present in $('<p></p>')
  //TODO: investigage a better detection method
  is$: function(obj) {
    return typeof obj === 'object' && ('length' in obj);
  },
  expandToken: function(input, scope) {
    if (input && input.indexOf && input.indexOf('{{') >= 0) {
      var re = /(?:\{?[^{]+)|(?:\{\{([^}]+)\}\})/g,
          match,
          ret = [];
      function deref(token, scope) {
        if (token.match(/^("|')/) && token.match(/("|')$/)) {
          return token.replace(/(^("|')|('|")$)/g, '');
        }
        var segments = token.split('.'),
            len = segments.length;
        for (var i = 0; scope && i < len; i++) {
          if (segments[i] !== 'this') {
            scope = scope[segments[i]];
          }
        }
        return scope;
      }
      while (match = re.exec(input)) {
        if (match[1]) {
          var params = match[1].split(/\s+/);
          if (params.length > 1) {
            var helper = params.shift();
            params = _.map(params, function(param) { return deref(param, scope); });
            if (Handlebars.helpers[helper]) {
              ret.push(Handlebars.helpers[helper].apply(scope, params));
            } else {
              // If the helper is not defined do nothing
              ret.push(match[0]);
            }
          } else {
            ret.push(deref(params[0], scope));
          }
        } else {
          ret.push(match[0]);
        }
      }
      input = ret.join('');
    }
    return input;
  },
  tag: function(attributes, content, scope) {
    var htmlAttributes = _.omit(attributes, 'tagName'),
        tag = attributes.tagName || 'div';
    return '<' + tag + ' ' + _.map(htmlAttributes, function(value, key) {
      if (typeof value === 'undefined' || key === 'expand-tokens') {
        return '';
      }
      var formattedValue = value;
      if (scope) {
        formattedValue = Thorax.Util.expandToken(value, scope);
      }
      return (key === 'className' ? 'class' : key) + '="' + Handlebars.Utils.escapeExpression(formattedValue) + '"';
    }).join(' ') + '>' + (typeof content === 'undefined' ? '' : content) + '</' + tag + '>';
  }
};

;;
/*global createInheritVars, inheritVars */
Thorax.Mixins = {};

inheritVars.mixins = {
  name: 'mixins',
  configure: function() {
    _.each(this.constructor.mixins, this.mixin, this);
    _.each(this.mixins, this.mixin, this);
  }
};

_.extend(Thorax.View, {
  mixin: function(mixin) {
    createInheritVars(this);
    this.mixins.push(mixin);
  },
  registerMixin: function(name, callback, methods) {
    Thorax.Mixins[name] = [callback, methods];
  }
});

Thorax.View.prototype.mixin = function(name) {
  if (!this._appliedMixins) {
    this._appliedMixins = [];
  }
  if (this._appliedMixins.indexOf(name) === -1) {
    this._appliedMixins.push(name);
    if (typeof name === 'function') {
      name.call(this);
    } else {
      var mixin = Thorax.Mixins[name];
      _.extend(this, mixin[1]);
      //mixin callback may be an array of [callback, arguments]
      if (_.isArray(mixin[0])) {
        mixin[0][0].apply(this, mixin[0][1]);
      } else {
        mixin[0].apply(this, _.toArray(arguments).slice(1));
      }
    }
  }
};

;;
/*global createInheritVars, inheritVars, objectEvents, walkInheritTree */
// Save a copy of the _on method to call as a $super method
var _on = Thorax.View.prototype.on;

inheritVars.event = {
  name: '_events',

  configure: function() {
    var self = this;
    walkInheritTree(this.constructor, '_events', true, function(event) {
      self.on.apply(self, event);
    });
    walkInheritTree(this, 'events', false, function(handler, eventName) {
      self.on(eventName, handler, self);
    });
  }
};

_.extend(Thorax.View, {
  on: function(eventName, callback) {
    createInheritVars(this);

    if (objectEvents(this, eventName, callback)) {
      return this;
    }

    //accept on({"rendered": handler})
    if (typeof eventName === 'object') {
      _.each(eventName, function(value, key) {
        this.on(key, value);
      }, this);
    } else {
      //accept on({"rendered": [handler, handler]})
      if (_.isArray(callback)) {
        _.each(callback, function(cb) {
          this._events.push([eventName, cb]);
        }, this);
      //accept on("rendered", handler)
      } else {
        this._events.push([eventName, callback]);
      }
    }
    return this;
  }
});

_.extend(Thorax.View.prototype, {
  on: function(eventName, callback, context) {
    if (objectEvents(this, eventName, callback, context)) {
      return this;
    }

    if (typeof eventName === 'object' && arguments.length < 3) {
      //accept on({"rendered": callback})
      _.each(eventName, function(value, key) {
        this.on(key, value, callback || this);    // callback is context in this form of the call
      }, this);
    } else {
      //accept on("rendered", callback, context)
      //accept on("click a", callback, context)
      _.each((_.isArray(callback) ? callback : [callback]), function(callback) {
        var params = eventParamsFromEventItem.call(this, eventName, callback, context || this);
        if (params.type === 'DOM') {
          //will call _addEvent during delegateEvents()
          if (!this._eventsToDelegate) {
            this._eventsToDelegate = [];
          }
          this._eventsToDelegate.push(params);
        } else {
          this._addEvent(params);
        }
      }, this);
    }
    return this;
  },
  delegateEvents: function(events) {
    this.undelegateEvents();
    if (events) {
      if (_.isFunction(events)) {
        events = events.call(this);
      }
      this._eventsToDelegate = [];
      this.on(events);
    }
    this._eventsToDelegate && _.each(this._eventsToDelegate, this._addEvent, this);
  },
  //params may contain:
  //- name
  //- originalName
  //- selector
  //- type "view" || "DOM"
  //- handler
  _addEvent: function(params) {
    if (params.type === 'view') {
      _.each(params.name.split(/\s+/), function(name) {
        _on.call(this, name, bindEventHandler.call(this, 'view-event:', params));
      }, this);
    } else {
      var boundHandler = bindEventHandler.call(this, 'dom-event:', params);
      if (!params.nested) {
        boundHandler = containHandlerToCurentView(boundHandler, this.cid);
      }
      if (params.selector) {
        var name = params.name + '.delegateEvents' + this.cid;
        this.$el.on(name, params.selector, boundHandler);
      } else {
        this.$el.on(params.name, boundHandler);
      }
    }
  }
});

// When view is ready trigger ready event on all
// children that are present, then register an
// event that will trigger ready on new children
// when they are added
Thorax.View.on('ready', function(options) {
  if (!this._isReady) {
    this._isReady = true;
    function triggerReadyOnChild(child) {
      child.trigger('ready', options);
    }
    _.each(this.children, triggerReadyOnChild);
    this.on('child', triggerReadyOnChild);
  }
});

var eventSplitter = /^(nested\s+)?(\S+)(?:\s+(.+))?/;

var domEvents = [],
    domEventRegexp;
function pushDomEvents(events) {
  domEvents.push.apply(domEvents, events);
  domEventRegexp = new RegExp('^(nested\\s+)?(' + domEvents.join('|') + ')(?:\\s|$)');
}
pushDomEvents([
  'mousedown', 'mouseup', 'mousemove', 'mouseover', 'mouseout',
  'touchstart', 'touchend', 'touchmove',
  'click', 'dblclick',
  'keyup', 'keydown', 'keypress',
  'submit', 'change',
  'focus', 'blur'
]);

function containHandlerToCurentView(handler, cid) {
  return function(event) {
    var view = $(event.target).view({helper: false});
    if (view && view.cid === cid) {
      event.originalContext = this;
      handler(event);
    }
  };
}

function bindEventHandler(eventName, params) {
  eventName += params.originalName;

  var callback = params.handler,
      method = typeof callback === 'function' ? callback : this[callback];
  if (!method) {
    throw new Error('Event "' + callback + '" does not exist ' + (this.name || this.cid) + ':' + eventName);
  }
  return _.bind(function() {
    try {
      method.apply(this, arguments);
    } catch (e) {
      Thorax.onException('thorax-exception: ' + (this.name || this.cid) + ':' + eventName, e);
    }
  }, params.context || this);
}

function eventParamsFromEventItem(name, handler, context) {
  var params = {
    originalName: name,
    handler: typeof handler === 'string' ? this[handler] : handler
  };
  if (name.match(domEventRegexp)) {
    var match = eventSplitter.exec(name);
    params.nested = !!match[1];
    params.name = match[2];
    params.type = 'DOM';
    params.selector = match[3];
  } else {
    params.name = name;
    params.type = 'view';
  }
  params.context = context;
  return params;
}

;;
/*global getOptionsData, viewHelperAttributeName */
var viewPlaceholderAttributeName = 'data-view-tmp';
var viewTemplateOverrides = {};

Thorax.HelperView = Thorax.View.extend({
  _ensureElement: function() {
    Thorax.View.prototype._ensureElement.apply(this, arguments);
    this.$el.attr(viewHelperAttributeName, this._helperName);
  },
  _getContext: function() {
    return this.parent._getContext.apply(this.parent, arguments);
  },
});

// Ensure nested inline helpers will always have this.parent
// set to the view containing the template
function getParent(parent) {
  // The `view` helper is a special case as it embeds
  // a view instead of creating a new one
  while (parent._helperName && parent._helperName !== 'view') {
    parent = parent.parent;
  }
  return parent;
}

Handlebars.registerViewHelper = function(name, ViewClass, callback) {
  if (arguments.length === 2) {
    if (ViewClass.factory) {
      callback = ViewClass.callback;
    } else {
      callback = ViewClass;
      ViewClass = Thorax.HelperView;
    }
  }
  Handlebars.registerHelper(name, function() {
    var args = _.toArray(arguments),
        options = args.pop(),
        declaringView = getOptionsData(options).view;

    var viewOptions = {
      template: options.fn || Handlebars.VM.noop,
      inverse: options.inverse,
      options: options.hash,
      declaringView: declaringView,
      parent: getParent(declaringView),
      _helperName: name,
      _helperOptions: {
        options: cloneHelperOptions(options),
        args: _.clone(args)
      }
    };

    normalizeHTMLAttributeOptions(options.hash);
    _.extend(viewOptions, _.pick(options.hash, htmlAttributesToCopy));

    // Check to see if we have an existing instance that we can reuse
    var instance = _.find(declaringView._previousHelpers, function(child) {
      return compareHelperOptions(viewOptions, child);
    });

    // Create the instance if we don't already have one
    if (!instance) {
      if (ViewClass.factory) {
        instance = ViewClass.factory(args, viewOptions);
        if (!instance) {
          return '';
        }

        instance._helperName = viewOptions._helperName;
        instance._helperOptions = viewOptions._helperOptions;
      } else {
        instance = new ViewClass(viewOptions);
      }

      args.push(instance);
      declaringView._addChild(instance);
      declaringView.trigger.apply(declaringView, ['helper', name].concat(args));
      declaringView.trigger.apply(declaringView, ['helper:' + name].concat(args));

      callback && callback.apply(this, args);
    } else {
      declaringView._previousHelpers = _.without(declaringView._previousHelpers, instance);
      declaringView.children[instance.cid] = instance;
    }

    var htmlAttributes = _.pick(options.hash, htmlAttributesToCopy);
    htmlAttributes[viewPlaceholderAttributeName] = instance.cid;

    var expandTokens = options.hash['expand-tokens'];
    return new Handlebars.SafeString(Thorax.Util.tag(htmlAttributes, '', expandTokens ? this : null));
  });
  var helper = Handlebars.helpers[name];
  return helper;
};

Thorax.View.on('append', function(scope, callback) {
  (scope || this.$el).find('[' + viewPlaceholderAttributeName + ']').forEach(function(el) {
    var placeholderId = el.getAttribute(viewPlaceholderAttributeName),
        view = this.children[placeholderId];
    if (view) {
      //see if the view helper declared an override for the view
      //if not, ensure the view has been rendered at least once
      if (viewTemplateOverrides[placeholderId]) {
        view.render(viewTemplateOverrides[placeholderId]);
        delete viewTemplateOverrides[placeholderId];
      } else {
        view.ensureRendered();
      }
      $(el).replaceWith(view.el);
      callback && callback(view.el);
    }
  }, this);
});


/**
 * Clones the helper options, dropping items that are known to change
 * between rendering cycles as appropriate.
 */
function cloneHelperOptions(options) {
  var ret = _.pick(options, 'fn', 'inverse', 'hash', 'data');
  ret.data = _.omit(options.data, 'cid', 'view', 'yield');
  return ret;
}

/**
 * Checks for basic equality between two sets of parameters for a helper view.
 *
 * Checked fields include:
 *  - _helperName
 *  - All args
 *  - Hash
 *  - Data
 *  - Function and Invert (id based if possible)
 *
 * This method allows us to determine if the inputs to a given view are the same. If they
 * are then we make the assumption that the rendering will be the same (or the child view will
 * otherwise rerendering it by monitoring it's parameters as necessary) and reuse the view on
 * rerender of the parent view.
 */
function compareHelperOptions(a, b) {
  function compareValues(a, b) {
    return _.every(a, function(value, key) {
      return b[key] === value;
    });
  }

  if (a._helperName !== b._helperName) {
    return false;
  }

  a = a._helperOptions;
  b = b._helperOptions;

  // Implements a first level depth comparison
  return a.args.length === b.args.length
      && compareValues(a.args, b.args)
      && _.isEqual(_.keys(a.options), _.keys(b.options))
      && _.every(a.options, function(value, key) {
          if (key === 'data' || key === 'hash') {
            return compareValues(a.options[key], b.options[key]);
          } else if (key === 'fn' || key === 'inverse') {
            return b.options[key] === value
                || (value && _.has(value, 'program') && ((b.options[key] || {}).program === value.program));
          }
          return b.options[key] === value;
        });
}

;;
/*global getValue, inheritVars, walkInheritTree */

function dataObject(type, spec) {
  spec = inheritVars[type] = _.defaults({
    name: '_' + type + 'Events',
    event: true
  }, spec);

  // Add a callback in the view constructor
  spec.ctor = function() {
    if (this[type]) {
      // Need to null this.model/collection so setModel/Collection will
      // not treat it as the old model/collection and immediately return
      var object = this[type];
      this[type] = null;
      this[spec.set](object);
    }
  };

  function setObject(dataObject, options) {
    var old = this[type],
        $el = getValue(this, spec.$el);

    if (dataObject === old) {
      return this;
    }
    if (old) {
      this.unbindDataObject(old);
    }

    if (dataObject) {
      this[type] = dataObject;

      if (spec.loading) {
        spec.loading.call(this);
      }

      this.bindDataObject(type, dataObject, _.extend({}, this.options, options));
      $el.attr(spec.cidAttrName, dataObject.cid);
      dataObject.trigger('set', dataObject, old);
    } else {
      this[type] = false;
      if (spec.change) {
        spec.change.call(this, false);
      }
      $el.removeAttr(spec.cidAttrName);
    }
    this.trigger('change:data-object', type, dataObject, old);
    return this;
  }

  Thorax.View.prototype[spec.set] = setObject;
}

_.extend(Thorax.View.prototype, {
  bindDataObject: function(type, dataObject, options) {
    if (this._boundDataObjectsByCid[dataObject.cid]) {
      return false;
    }
    this._boundDataObjectsByCid[dataObject.cid] = dataObject;

    var options = this._modifyDataObjectOptions(dataObject, _.extend({}, inheritVars[type].defaultOptions, options));
    this._objectOptionsByCid[dataObject.cid] = options;

    bindEvents.call(this, type, dataObject, this.constructor);
    bindEvents.call(this, type, dataObject, this);

    var spec = inheritVars[type];
    spec.bindCallback && spec.bindCallback.call(this, dataObject, options);

    if (dataObject.shouldFetch && dataObject.shouldFetch(options)) {
      loadObject(dataObject, options);
    } else if (inheritVars[type].change) {
      // want to trigger built in rendering without triggering event on model
      inheritVars[type].change.call(this, dataObject, options);
    }

    return true;
  },

  unbindDataObject: function (dataObject) {
    if (!this._boundDataObjectsByCid[dataObject.cid]) {
      return false;
    }
    delete this._boundDataObjectsByCid[dataObject.cid];
    this.stopListening(dataObject);
    delete this._objectOptionsByCid[dataObject.cid];
    return true;
  },

  _modifyDataObjectOptions: function(dataObject, options) {
    return options;
  }
});

function bindEvents(type, target, source) {
  var context = this;
  walkInheritTree(source, '_' + type + 'Events', true, function(event) {
    // getEventCallback will resolve if it is a string or a method
    // and return a method
    context.listenTo(target, event[0], _.bind(getEventCallback(event[1], context), event[2] || context));
  });
}

function loadObject(dataObject, options) {
  if (dataObject.load) {
    dataObject.load(function() {
      options && options.success && options.success(dataObject);
    }, options);
  } else {
    dataObject.fetch(options);
  }
}

function getEventCallback(callback, context) {
  if (typeof callback === 'function') {
    return callback;
  } else {
    return context[callback];
  }
}

;;
/*global createRegistryWrapper, dataObject, getValue */
var modelCidAttributeName = 'data-model-cid';

Thorax.Model = Backbone.Model.extend({
  isEmpty: function() {
    return !this.isPopulated();
  },
  isPopulated: function() {
    // We are populated if we have attributes set
    var attributes = _.clone(this.attributes),
        defaults = getValue(this, 'defaults') || {};
    for (var default_key in defaults) {
      if (attributes[default_key] != defaults[default_key]) {
        return true;
      }
      delete attributes[default_key];
    }
    var keys = _.keys(attributes);
    return keys.length > 1 || (keys.length === 1 && keys[0] !== this.idAttribute);
  },
  shouldFetch: function(options) {
    // url() will throw if model has no `urlRoot` and no `collection`
    // or has `collection` and `collection` has no `url`
    var url;
    try {
      url = getValue(this, 'url');
    } catch(e) {
      url = false;
    }
    return options.fetch && !!url && !this.isPopulated();
  }
});

Thorax.Models = {};
createRegistryWrapper(Thorax.Model, Thorax.Models);

dataObject('model', {
  set: 'setModel',
  defaultOptions: {
    render: true,
    fetch: true,
    success: false,
    errors: true
  },
  change: onModelChange,
  $el: '$el',
  cidAttrName: modelCidAttributeName
});

function onModelChange(model) {
  var modelOptions = model && this._objectOptionsByCid[model.cid];
  // !modelOptions will be true when setModel(false) is called
  if (!modelOptions || (modelOptions && modelOptions.render)) {
    this.render();
  }
}

Thorax.View.on({
  model: {
    error: function(model, errors) {
      if (this._objectOptionsByCid[model.cid].errors) {
        this.trigger('error', errors, model);
      }
    },
    change: function(model) {
      onModelChange.call(this, model);
    }
  }
});

$.fn.model = function(view) {
  var $this = $(this),
      modelElement = $this.closest('[' + modelCidAttributeName + ']'),
      modelCid = modelElement && modelElement.attr(modelCidAttributeName);
  if (modelCid) {
    var view = view || $this.view();
    if (view && view.model && view.model.cid === modelCid) {
      return view.model || false;
    }
    var collection = $this.collection(view);
    if (collection) {
      return collection.get(modelCid);
    }
  }
  return false;
};

;;
/*global createRegistryWrapper, dataObject, getEventCallback, getValue, modelCidAttributeName, viewCidAttributeName */
var _fetch = Backbone.Collection.prototype.fetch,
    _reset = Backbone.Collection.prototype.reset,
    collectionCidAttributeName = 'data-collection-cid',
    collectionEmptyAttributeName = 'data-collection-empty',
    collectionElementAttributeName = 'data-collection-element',
    ELEMENT_NODE_TYPE = 1;

Thorax.Collection = Backbone.Collection.extend({
  model: Thorax.Model || Backbone.Model,
  initialize: function() {
    this.cid = _.uniqueId('collection');
    return Backbone.Collection.prototype.initialize.apply(this, arguments);
  },
  isEmpty: function() {
    if (this.length > 0) {
      return false;
    } else {
      return this.length === 0 && this.isPopulated();
    }
  },
  isPopulated: function() {
    return this._fetched || this.length > 0 || (!this.length && !getValue(this, 'url'));
  },
  shouldFetch: function(options) {
    return options.fetch && !!getValue(this, 'url') && !this.isPopulated();
  },
  fetch: function(options) {
    options = options || {};
    var success = options.success;
    options.success = function(collection, response) {
      collection._fetched = true;
      success && success(collection, response);
    };
    return _fetch.apply(this, arguments);
  },
  reset: function(models, options) {
    this._fetched = !!models;
    return _reset.call(this, models, options);
  }
});

Thorax.Collections = {};
createRegistryWrapper(Thorax.Collection, Thorax.Collections);

dataObject('collection', {
  set: 'setCollection',
  bindCallback: onSetCollection,
  defaultOptions: {
    render: true,
    fetch: true,
    success: false,
    errors: true
  },
  change: onCollectionReset,
  $el: 'getCollectionElement',
  cidAttrName: collectionCidAttributeName
});

_.extend(Thorax.View.prototype, {
  _collectionSelector: '[' + collectionElementAttributeName + ']',
  //appendItem(model [,index])
  //appendItem(html_string, index)
  //appendItem(view, index)
  appendItem: function(model, index, options) {
    //empty item
    if (!model) {
      return;
    }
    var itemView,
        $el = this.getCollectionElement();
    options = _.defaults(options || {}, {
      filter: true
    });
    //if index argument is a view
    index && index.el && (index = $el.children().indexOf(index.el) + 1);
    //if argument is a view, or html string
    if (model.el || typeof model === 'string') {
      itemView = model;
      model = false;
    } else {
      index = index || this.collection.indexOf(model) || 0;
      itemView = this.renderItem(model, index);
    }
    if (itemView) {
      itemView.cid && this._addChild(itemView);
      //if the renderer's output wasn't contained in a tag, wrap it in a div
      //plain text, or a mixture of top level text nodes and element nodes
      //will get wrapped
      if (typeof itemView === 'string' && !itemView.match(/^\s*</m)) {
        itemView = '<div>' + itemView + '</div>';
      }
      var itemElement = itemView.el ? [itemView.el] : _.filter($(itemView), function(node) {
        //filter out top level whitespace nodes
        return node.nodeType === ELEMENT_NODE_TYPE;
      });
      model && $(itemElement).attr(modelCidAttributeName, model.cid);
      var previousModel = index > 0 ? this.collection.at(index - 1) : false;
      if (!previousModel) {
        $el.prepend(itemElement);
      } else {
        //use last() as appendItem can accept multiple nodes from a template
        var last = $el.find('[' + modelCidAttributeName + '="' + previousModel.cid + '"]').last();
        last.after(itemElement);
      }

      this.trigger('append', null, function(el) {
        el.setAttribute(modelCidAttributeName, model.cid);
      });

      !options.silent && this.trigger('rendered:item', this, this.collection, model, itemElement, index);
      options.filter && applyItemVisiblityFilter.call(this, model);
    }
    return itemView;
  },
  // updateItem only useful if there is no item view, otherwise
  // itemView.render() provides the same functionality
  updateItem: function(model) {
    this.removeItem(model);
    this.appendItem(model);
  },
  removeItem: function(model) {
    var $el = this.getCollectionElement(),
        viewEl = $el.find('[' + modelCidAttributeName + '="' + model.cid + '"]');
    if (!viewEl.length) {
      return false;
    }
    viewEl.remove();
    var viewCid = viewEl.attr(viewCidAttributeName),
        child = this.children[viewCid];
    if (child) {
      this._removeChild(child);
      child.destroy();
    }
    return true;
  },
  renderCollection: function() {
    this.ensureRendered();
    if (!this.collectionRenderer) {
      return;
    }
    if (this.collection) {
      if (this.collection.isEmpty()) {
        handleChangeFromNotEmptyToEmpty.call(this);
      } else {
        handleChangeFromEmptyToNotEmpty.call(this);
        this.collection.forEach(function(item, i) {
          this.appendItem(item, i);
        }, this);
      }
      this.trigger('rendered:collection', this, this.collection);
      applyVisibilityFilter.call(this);
    } else {
      handleChangeFromNotEmptyToEmpty.call(this);
    }
  },
  emptyClass: 'empty',
  renderEmpty: function() {
    if (this.emptyView) {
      var viewOptions = {};
      if (this.emptyTemplate) {
        viewOptions.template = this.emptyTemplate;
      }
      var view = Thorax.Util.getViewInstance(this.emptyView, viewOptions);
      view.ensureRendered();
      return view;
    } else {
      if (!this.emptyTemplate) {
        this.emptyTemplate = Thorax.Util.getTemplate(this.name + '-empty', true);
      }
      return this.emptyTemplate && this.renderTemplate(this.emptyTemplate);
    }
  },
  renderItem: function(model, i) {
    if (this.itemView) {
      var viewOptions = {
        model: model
      };
      if (this.itemTemplate) {
        viewOptions.template = this.itemTemplate;
      }
      var view = Thorax.Util.getViewInstance(this.itemView, viewOptions);
      view.ensureRendered();
      return view;
    } else {
      if (!this.itemTemplate) {
        this.itemTemplate = Thorax.Util.getTemplate(this.name + '-item');
      }
      return this.renderTemplate(this.itemTemplate, this.itemContext(model, i));
    }
  },
  itemContext: function(model /*, i */) {
    return model.attributes;
  },
  appendEmpty: function() {
    var $el = this.getCollectionElement();
    $el.empty();
    var emptyContent = this.renderEmpty();
    emptyContent && this.appendItem(emptyContent, 0, {
      silent: true,
      filter: false
    });
    this.trigger('rendered:empty', this, this.collection);
  },
  getCollectionElement: function() {
    var element = this.$(this._collectionSelector);
    return element.length === 0 ? this.$el : element;
  },
  // Events that will only be bound to "this.collection"
  _collectionRenderingEvents: {
    reset: onCollectionReset,
    sort: onCollectionReset,
    filter: function() {
      applyVisibilityFilter.call(this);
    },
    change: function(model) {
      // If we rendered with item views, model changes will be observed
      // by the generated item view but if we rendered with templates
      // then model changes need to be bound as nothing is watching
      !this.itemView && this.updateItem(model);
      applyItemVisiblityFilter.call(this, model);
    },
    add: function(model) {
      var $el = this.getCollectionElement();
      this.collection.length === 1 && $el.length && handleChangeFromEmptyToNotEmpty.call(this);
      if ($el.length) {
        var index = this.collection.indexOf(model);
        this.appendItem(model, index);
      }
    },
    remove: function(model) {
      var $el = this.getCollectionElement();
      this.removeItem(model);
      this.collection.length === 0 && $el.length && handleChangeFromNotEmptyToEmpty.call(this);
    }
  }
});

Thorax.View.on({
  collection: {
    error: function(collection, message) {
      if (this._objectOptionsByCid[collection.cid].errors) {
        this.trigger('error', message, collection);
      }
    }
  }
});

function onCollectionReset(collection) {
  var options = collection && this._objectOptionsByCid[collection.cid];
  // we would want to still render in the case that the
  // collection has transitioned to being falsy
  if (!collection || (options && options.render)) {
    this.renderCollection();
  }
}

function onSetCollection(collection) {
  if (this.collectionRenderer && collection) {
    _.each(this._collectionRenderingEvents, function(callback, eventName) {
      // getEventCallback will resolve if it is a string or a method
      // and return a method
      this.listenTo(collection, eventName, getEventCallback(callback, this));
    }, this);
  }
}

function applyVisibilityFilter() {
  if (this.itemFilter) {
    this.collection.forEach(function(model) {
      applyItemVisiblityFilter.call(this, model);
    }, this);
  }
}

function applyItemVisiblityFilter(model) {
  var $el = this.getCollectionElement();
  this.itemFilter && $el.find('[' + modelCidAttributeName + '="' + model.cid + '"]')[itemShouldBeVisible.call(this, model) ? 'show' : 'hide']();
}

function itemShouldBeVisible(model) {
  return this.itemFilter(model, this.collection.indexOf(model));
}

function handleChangeFromEmptyToNotEmpty() {
  var $el = this.getCollectionElement();
  this.emptyClass && $el.removeClass(this.emptyClass);
  $el.removeAttr(collectionEmptyAttributeName);
  $el.empty();
}

function handleChangeFromNotEmptyToEmpty() {
  var $el = this.getCollectionElement();
  this.emptyClass && $el.addClass(this.emptyClass);
  $el.attr(collectionEmptyAttributeName, true);
  this.appendEmpty();
}

//$(selector).collection() helper
$.fn.collection = function(view) {
  if (view && view.collection) {
    return view.collection;
  }
  var $this = $(this),
      collectionElement = $this.closest('[' + collectionCidAttributeName + ']'),
      collectionCid = collectionElement && collectionElement.attr(collectionCidAttributeName);
  if (collectionCid) {
    view = $this.view();
    if (view) {
      return view.collection;
    }
  }
  return false;
};

;;
/*global inheritVars */

inheritVars.model.defaultOptions.populate = true;

var oldModelChange = inheritVars.model.change;
inheritVars.model.change = function() {
  oldModelChange.apply(this, arguments);
  // TODO : What can we do to remove this duplication?
  var modelOptions = this.model && this._objectOptionsByCid[this.model.cid];
  if (modelOptions && modelOptions.populate) {
    this.populate(this.model.attributes, modelOptions.populate === true ? {} : modelOptions.populate);
  }
};
inheritVars.model.defaultOptions.populate = true;

_.extend(Thorax.View.prototype, {
  //serializes a form present in the view, returning the serialized data
  //as an object
  //pass {set:false} to not update this.model if present
  //can pass options, callback or event in any order
  serialize: function() {
    var callback, options, event;
    //ignore undefined arguments in case event was null
    for (var i = 0; i < arguments.length; ++i) {
      if (typeof arguments[i] === 'function') {
        callback = arguments[i];
      } else if (typeof arguments[i] === 'object') {
        if ('stopPropagation' in arguments[i] && 'preventDefault' in arguments[i]) {
          event = arguments[i];
        } else {
          options = arguments[i];
        }
      }
    }

    if (event && !this._preventDuplicateSubmission(event)) {
      return;
    }

    options = _.extend({
      set: true,
      validate: true,
      children: true,
      silent: true
    }, options || {});

    var attributes = options.attributes || {};

    //callback has context of element
    var view = this;
    var errors = [];
    eachNamedInput.call(this, options, function() {
      var value = view._getInputValue(this, options, errors);
      if (typeof value !== 'undefined') {
        objectAndKeyFromAttributesAndName.call(this, attributes, this.name, {mode: 'serialize'}, function(object, key) {
          if (!object[key]) {
            object[key] = value;
          } else if (_.isArray(object[key])) {
            object[key].push(value);
          } else {
            object[key] = [object[key], value];
          }
        });
      }
    });

    this.trigger('serialize', attributes, options);

    if (options.validate) {
      var validateInputErrors = this.validateInput(attributes);
      if (validateInputErrors && validateInputErrors.length) {
        errors = errors.concat(validateInputErrors);
      }
      this.trigger('validate', attributes, errors, options);
      if (errors.length) {
        this.trigger('error', errors);
        return;
      }
    }

    if (options.set && this.model) {
      if (!this.model.set(attributes, {silent: options.silent})) {
        return false;
      }
    }

    callback && callback.call(this, attributes, _.bind(resetSubmitState, this));
    return attributes;
  },

  _preventDuplicateSubmission: function(event, callback) {
    event.preventDefault();

    var form = $(event.target);
    if ((event.target.tagName || '').toLowerCase() !== 'form') {
      // Handle non-submit events by gating on the form
      form = $(event.target).closest('form');
    }

    if (!form.attr('data-submit-wait')) {
      form.attr('data-submit-wait', 'true');
      if (callback) {
        callback.call(this, event);
      }
      return true;
    } else {
      return false;
    }
  },

  //populate a form from the passed attributes or this.model if present
  populate: function(attributes, options) {
    options = _.extend({
      children: true
    }, options || {});
    var value, attributes = attributes || this._getContext();
    //callback has context of element
    eachNamedInput.call(this, options, function() {
      objectAndKeyFromAttributesAndName.call(this, attributes, this.name, {mode: 'populate'}, function(object, key) {
        if (object && typeof (value = object[key]) !== 'undefined') {
          //will only execute if we have a name that matches the structure in attributes
          if (this.type === 'checkbox' && _.isBoolean(value)) {
            this.checked = value;
          } else if (this.type === 'checkbox' || this.type === 'radio') {
            this.checked = value == this.value;
          } else {
            this.value = value;
          }
        }
      });
    });

    this.trigger('populate', attributes);
  },

  //perform form validation, implemented by child class
  validateInput: function(/* attributes, options, errors */) {},

  _getInputValue: function(input /* , options, errors */) {
    if (input.type === 'checkbox' || input.type === 'radio') {
      if (input.checked) {
        return input.value;
      }
    } else if (input.multiple === true) {
      var values = [];
      $('option', input).each(function() {
        if (this.selected) {
          values.push(this.value);
        }
      });
      return values;
    } else {
      return input.value;
    }
  }
});

Thorax.View.on({
  error: function() {
    resetSubmitState.call(this);

    // If we errored with a model we want to reset the content but leave the UI
    // intact. If the user updates the data and serializes any overwritten data
    // will be restored.
    if (this.model && this.model.previousAttributes) {
      this.model.set(this.model.previousAttributes(), {
        silent: true
      });
    }
  },
  deactivated: function() {
    resetSubmitState.call(this);
  }
});

function eachNamedInput(options, iterator, context) {
  var i = 0,
      self = this;

  this.$('select,input,textarea', options.root || this.el).each(function() {
    if (!options.children) {
      if (self !== $(this).view({helper: false})) {
        return;
      }
    }
    if (this.type !== 'button' && this.type !== 'cancel' && this.type !== 'submit' && this.name && this.name !== '') {
      iterator.call(context || this, i, this);
      ++i;
    }
  });
}

//calls a callback with the correct object fragment and key from a compound name
function objectAndKeyFromAttributesAndName(attributes, name, options, callback) {
  var key,
      object = attributes,
      keys = name.split('['),
      mode = options.mode;

  for (var i = 0; i < keys.length - 1; ++i) {
    key = keys[i].replace(']', '');
    if (!object[key]) {
      if (mode === 'serialize') {
        object[key] = {};
      } else {
        return callback.call(this, false, key);
      }
    }
    object = object[key];
  }
  key = keys[keys.length - 1].replace(']', '');
  callback.call(this, object, key);
}

function resetSubmitState() {
  this.$('form').removeAttr('data-submit-wait');
}

;;
var layoutCidAttributeName = 'data-layout-cid';

Thorax.LayoutView = Thorax.View.extend({
  render: function(output) {
    //TODO: fixme, lumbar inserts templates after JS, most of the time this is fine
    //but Application will be created in init.js (unlike most views)
    //so need to put this here so the template will be picked up
    var layoutTemplate;
    if (this.name) {
      layoutTemplate = Thorax.Util.getTemplate(this.name, true);
    }
    //a template is optional in a layout
    if (output || this.template || layoutTemplate) {
      //but if present, it must have embedded an element containing layoutCidAttributeName
      var response = Thorax.View.prototype.render.call(this, output || this.template || layoutTemplate);
      ensureLayoutViewsTargetElement.call(this);
      return response;
    } else {
      ensureLayoutCid.call(this);
    }
  },
  setView: function(view, options) {
    options = _.extend({
      scroll: true,
      destroy: true
    }, options || {});
    if (typeof view === 'string') {
      view = new (Thorax.Util.registryGet(Thorax, 'Views', view, false))();
    }
    this.ensureRendered();
    var oldView = this._view;
    if (view === oldView) {
      return false;
    }
    if (options.destroy && view) {
      view._shouldDestroyOnNextSetView = true;
    }

    this.trigger('change:view:start', view, oldView, options);

    if (oldView) {
      this._removeChild(oldView);
      oldView.$el.remove();
      triggerLifecycleEvent.call(oldView, 'deactivated', options);
      if (oldView._shouldDestroyOnNextSetView) {
        oldView.destroy();
      }
    }

    if (view) {
      triggerLifecycleEvent.call(this, 'activated', options);
      view.trigger('activated', options);
      this._addChild(view);
      this._view = view;
      this._view.appendTo(getLayoutViewsTargetElement.call(this));
    } else {
      this._view = undefined;
    }

    this.trigger('change:view:end', view, oldView, options);
    return view;
  },

  getView: function() {
    return this._view;
  }
});

Handlebars.registerHelper('layout', function(options) {
  options.hash[layoutCidAttributeName] = getOptionsData(options).view.cid;
  return new Handlebars.SafeString(Thorax.Util.tag.call(this, options.hash, '', this));
});

function triggerLifecycleEvent(eventName, options) {
  options = options || {};
  options.target = this;
  this.trigger(eventName, options);
  _.each(this.children, function(child) {
    child.trigger(eventName, options);
  });
}

function ensureLayoutCid() {
  ++this._renderCount;
  //set the layoutCidAttributeName on this.$el if there was no template
  this.$el.attr(layoutCidAttributeName, this.cid);
}

function ensureLayoutViewsTargetElement() {
  if (!this.$('[' + layoutCidAttributeName + '="' + this.cid + '"]')[0]) {
    throw new Error('No layout element found in ' + (this.name || this.cid));
  }
}

function getLayoutViewsTargetElement() {
  return this.$('[' + layoutCidAttributeName + '="' + this.cid + '"]')[0] || this.el[0] || this.el;
}

;;
/*global createRegistryWrapper */

//Router
function initializeRouter() {
  Backbone.history || (Backbone.history = new Backbone.History());
  Backbone.history.on('route', onRoute, this);
  //router does not have a built in destroy event
  //but ViewController does
  this.on('destroyed', function() {
    Backbone.history.off('route', onRoute, this);
  });
}

Thorax.Router = Backbone.Router.extend({
  constructor: function() {
    var response = Thorax.Router.__super__.constructor.apply(this, arguments);
    initializeRouter.call(this);
    return response;
  },
  route: function(route, name, callback) {
    if (!callback) {
      callback = this[name];
    }
    //add a route:before event that is fired before the callback is called
    return Backbone.Router.prototype.route.call(this, route, name, function() {
      this.trigger.apply(this, ['route:before', route, name].concat(Array.prototype.slice.call(arguments)));
      return callback.apply(this, arguments);
    });
  }
});

Thorax.Routers = {};
createRegistryWrapper(Thorax.Router, Thorax.Routers);

function onRoute(router /* , name */) {
  if (this === router) {
    this.trigger.apply(this, ['route'].concat(Array.prototype.slice.call(arguments, 1)));
  }
}

;;
Thorax.CollectionHelperView = Thorax.HelperView.extend({
  // Forward render events to the parent
  events: {
    'rendered:item': forwardRenderEvent('rendered:item'),
    'rendered:collection': forwardRenderEvent('rendered:collection'),
    'rendered:empty': forwardRenderEvent('rendered:empty')
  },
  collectionRenderer: true,

  constructor: function(options) {
    _.each(collectionOptionNames, function(viewAttributeName, helperOptionName) {
      if (options.options[helperOptionName]) {
        var value = options.options[helperOptionName];
        if (viewAttributeName === 'itemTemplate' || viewAttributeName === 'emptyTemplate') {
          value = Thorax.Util.getTemplate(value);
        }
        options[viewAttributeName] = value;
      }
    });
    // Handlebars.VM.noop is passed in the handlebars options object as
    // a default for fn and inverse, if a block was present. Need to
    // check to ensure we don't pick the empty / null block up.
    if (!options.itemTemplate && options.template && options.template !== Handlebars.VM.noop) {
      options.itemTemplate = options.template;
      options.template = Handlebars.VM.noop;
    }
    if (!options.emptyTemplate && options.inverse && options.inverse !== Handlebars.VM.noop) {
      options.emptyTemplate = options.inverse;
      options.inverse = Handlebars.VM.noop;
    }
    !options.template && (options.template = Handlebars.VM.noop);
    var response = Thorax.HelperView.call(this, options);
    if (this.parent.name) {
      if (!this.emptyTemplate) {
        this.emptyTemplate = Thorax.Util.getTemplate(this.parent.name + '-empty', true);
      }
      if (!this.itemTemplate) {
        this.itemTemplate = Thorax.Util.getTemplate(this.parent.name + '-item', true);
      }
    }
    return response;
  },
  itemContext: function() {
    return this.parent.itemContext.apply(this.parent, arguments);
  },
  setAsPrimaryCollectionHelper: function() {
    _.each(forwardableProperties, function(propertyName) {
      forwardMissingProperty.call(this, propertyName);
    }, this);
    if (this.parent.itemFilter && !this.itemFilter) {
      this.itemFilter = function() {
        return this.parent.itemFilter.apply(this.parent, arguments);
      };
    }
  }
});

var collectionOptionNames = {
  'item-template': 'itemTemplate',
  'empty-template': 'emptyTemplate',
  'item-view': 'itemView',
  'empty-view': 'emptyView',
  'empty-class': 'emptyClass'
};

function forwardRenderEvent(eventName) {
  return function() {
    var args = _.toArray(arguments);
    args.unshift(eventName);
    this.parent.trigger.apply(this.parent, args);
  }
}

var forwardableProperties = [
  'itemTemplate',
  'itemView',
  'emptyTemplate',
  'emptyView'
];

function forwardMissingProperty(propertyName) {
  var parent = getParent(this);
  if (!this[propertyName]) {
    var prop = parent[propertyName];
    if (prop){
      this[propertyName] = prop;
    }
  }
}

Handlebars.registerViewHelper('collection', Thorax.CollectionHelperView, function(collection, view) {
  if (arguments.length === 1) {
    view = collection;
    collection = view.parent.collection;
    collection && view.setAsPrimaryCollectionHelper();
    view.$el.attr(collectionElementAttributeName, 'true');
    // propagate future changes to the parent's collection object
    // to the helper view
    view.listenTo(view.parent, 'change:data-object', function(type, dataObject) {
      if (type === 'collection') {
        view.setAsPrimaryCollectionHelper();
        view.setCollection(dataObject);
      }
    });
  }
  collection && view.setCollection(collection);
});

Handlebars.registerHelper('collection-element', function(options) {
  var hash = options.hash;
  normalizeHTMLAttributeOptions(hash);
  hash.tagName = hash.tagName || 'div';
  hash[collectionElementAttributeName] = true;
  return new Handlebars.SafeString(Thorax.Util.tag.call(this, hash, '', this));
});

;;
Handlebars.registerHelper('empty', function(dataObject, options) {
  if (arguments.length === 1) {
    options = dataObject;
  }
  var view = getOptionsData(options).view;
  if (arguments.length === 1) {
    dataObject = view.model;
  }
  // listeners for the empty helper rather than listeners
  // that are themselves empty
  if (!view._emptyListeners) {
    view._emptyListeners = {};
  }
  // duck type check for collection
  if (dataObject && !view._emptyListeners[dataObject.cid] && dataObject.models && ('length' in dataObject)) {
    view._emptyListeners[dataObject.cid] = true;
    view.listenTo(dataObject, 'remove', function() {
      if (dataObject.length === 0) {
        view.render();
      }
    });
    view.listenTo(dataObject, 'add', function() {
      if (dataObject.length === 1) {
        view.render();
      }
    });
    view.listenTo(dataObject, 'reset', function() {
      view.render();
    });
  }
  return !dataObject || dataObject.isEmpty() ? options.fn(this) : options.inverse(this);
});

;;
Handlebars.registerHelper('template', function(name, options) {
  var context = _.extend({fn: options && options.fn}, this, options ? options.hash : {});
  var output = getOptionsData(options).view.renderTemplate(name, context);
  return new Handlebars.SafeString(output);
});

Handlebars.registerHelper('yield', function(options) {
  return getOptionsData(options).yield && options.data.yield();
});

;;
Handlebars.registerHelper('url', function(url) {
  var fragment;
  if (arguments.length > 2) {
    fragment = _.map(_.head(arguments, arguments.length - 1), encodeURIComponent).join('/');
  } else {
    var options = arguments[1],
        hash = (options && options.hash) || options;
    if (hash && hash['expand-tokens']) {
      fragment = Thorax.Util.expandToken(url, this);
    } else {
      fragment = url;
    }
  }
  return (Backbone.history._hasPushState ? Backbone.history.options.root : '#') + fragment;
});

;;
/*global viewTemplateOverrides */
Handlebars.registerViewHelper('view', {
  factory: function(args, options) {
    var View = args.length >= 1 ? args[0] : Thorax.View;
    return Thorax.Util.getViewInstance(View, options.options);
  },
  callback: function() {
    var instance = arguments[arguments.length-1],
        options = instance._helperOptions.options,
        placeholderId = instance.cid;

    if (options.fn) {
      viewTemplateOverrides[placeholderId] = options.fn;
    }
  }
});

;;
var callMethodAttributeName = 'data-call-method',
    triggerEventAttributeName = 'data-trigger-event';

Handlebars.registerHelper('button', function(method, options) {
  if (arguments.length === 1) {
    options = method;
    method = options.hash.method;
  }
  var hash = options.hash,
      expandTokens = hash['expand-tokens'];
  delete hash['expand-tokens'];
  if (!method && !options.hash.trigger) {
    throw new Error("button helper must have a method name as the first argument or a 'trigger', or a 'method' attribute specified.");
  }
  normalizeHTMLAttributeOptions(hash);
  hash.tagName = hash.tagName || 'button';
  hash.trigger && (hash[triggerEventAttributeName] = hash.trigger);
  delete hash.trigger;
  method && (hash[callMethodAttributeName] = method);
  return new Handlebars.SafeString(Thorax.Util.tag(hash, options.fn ? options.fn(this) : '', expandTokens ? this : null));
});

Handlebars.registerHelper('link', function() {
  var args = _.toArray(arguments),
      options = args.pop(),
      hash = options.hash,
      // url is an array that will be passed to the url helper
      url = args.length === 0 ? [hash.href] : args,
      expandTokens = hash['expand-tokens'];
  delete hash['expand-tokens'];
  if (!url[0] && url[0] !== '') {
    throw new Error("link helper requires an href as the first argument or an 'href' attribute");
  }
  normalizeHTMLAttributeOptions(hash);
  url.push(options);
  hash.href = Handlebars.helpers.url.apply(this, url);
  hash.tagName = hash.tagName || 'a';
  hash.trigger && (hash[triggerEventAttributeName] = options.hash.trigger);
  delete hash.trigger;
  hash[callMethodAttributeName] = '_anchorClick';
  return new Handlebars.SafeString(Thorax.Util.tag(hash, options.fn ? options.fn(this) : '', expandTokens ? this : null));
});

var clickSelector = '[' + callMethodAttributeName + '], [' + triggerEventAttributeName + ']';

function handleClick(event) {
  var target = $(event.target),
      view = target.view({helper: false}),
      methodName = target.attr(callMethodAttributeName),
      eventName = target.attr(triggerEventAttributeName),
      methodResponse = false;
  methodName && (methodResponse = view[methodName].call(view, event));
  eventName && view.trigger(eventName, event);
  target.tagName === "A" && methodResponse === false && event.preventDefault();
}

var lastClickHandlerEventName;

function registerClickHandler() {
  unregisterClickHandler();
  lastClickHandlerEventName = Thorax._fastClickEventName || 'click';
  $(document).on(lastClickHandlerEventName, clickSelector, handleClick);
}

function unregisterClickHandler() {
  lastClickHandlerEventName && $(document).off(lastClickHandlerEventName, clickSelector, handleClick);
}

$(document).ready(function() {
  if (!Thorax._fastClickEventName) {
    registerClickHandler();
  }
});

;;
var elementPlaceholderAttributeName = 'data-element-tmp';

Handlebars.registerHelper('element', function(element, options) {
  normalizeHTMLAttributeOptions(options.hash);
  var cid = _.uniqueId('element'),
      declaringView = getOptionsData(options).view,
      htmlAttributes = _.pick(options.hash, htmlAttributesToCopy);
  htmlAttributes[elementPlaceholderAttributeName] = cid;
  declaringView._elementsByCid || (declaringView._elementsByCid = {});
  declaringView._elementsByCid[cid] = element;
  return new Handlebars.SafeString(Thorax.Util.tag(htmlAttributes));
});

Thorax.View.on('append', function(scope, callback) {
  (scope || this.$el).find('[' + elementPlaceholderAttributeName + ']').forEach(function(el) {
    var $el = $(el),
        cid = $el.attr(elementPlaceholderAttributeName),
        element = this._elementsByCid[cid];
    // A callback function may be specified as the value
    if (_.isFunction(element)) {
      element = element.call(this);
    }
    $el.replaceWith(element);
    callback && callback(element);
  }, this);
});

;;
Handlebars.registerHelper('super', function(options) {
  var declaringView = getOptionsData(options).view,
      parent = declaringView.constructor && declaringView.constructor.__super__;
  if (parent) {
    var template = parent.template;
    if (!template) {
      if (!parent.name) {
        throw new Error('Cannot use super helper when parent has no name or template.');
      }
      template = Thorax.Util.getTemplate(parent.name, false);
    }
    if (typeof template === 'string') {
      template = Handlebars.compile(template, {data: true});
    }
    return new Handlebars.SafeString(template(this, options));
  } else {
    return '';
  }
});

;;
/*global collectionOptionNames, inheritVars */

var loadStart = 'load:start',
    loadEnd = 'load:end',
    rootObject;

Thorax.setRootObject = function(obj) {
  rootObject = obj;
};

Thorax.loadHandler = function(start, end, context) {
  var loadCounter = _.uniqueId();
  return function(message, background, object) {
    var self = context || this;
    self._loadInfo = self._loadInfo || [];
    var loadInfo = self._loadInfo[loadCounter];

    function startLoadTimeout() {

      // If the timeout has been set already but has not triggered yet do nothing
      // Otherwise set a new timeout (either initial or for going from background to
      // non-background loading)
      if (loadInfo.timeout && !loadInfo.run) {
        return;
      }

      var loadingTimeout = self._loadingTimeoutDuration !== undefined ?
        self._loadingTimeoutDuration : Thorax.View.prototype._loadingTimeoutDuration;
      loadInfo.timeout = setTimeout(function() {
          try {
            loadInfo.run = true;
            start.call(self, loadInfo.message, loadInfo.background, loadInfo);
          } catch (e) {
            Thorax.onException('loadStart', e);
          }
        }, loadingTimeout * 1000);
    }

    if (!loadInfo) {
      loadInfo = self._loadInfo[loadCounter] = _.extend({
        events: [],
        timeout: 0,
        message: message,
        background: !!background
      }, Backbone.Events);
      startLoadTimeout();
    } else {
      clearTimeout(loadInfo.endTimeout);

      loadInfo.message = message;
      if (!background && loadInfo.background) {
        loadInfo.background = false;
        startLoadTimeout();
      }
    }

    // Prevent binds to the same object multiple times as this can cause very bad things
    // to happen for the load;load;end;end execution flow.
    if (loadInfo.events.indexOf(object) >= 0) {
      loadInfo.events.push(object);
      return;
    }

    loadInfo.events.push(object);

    object.on(loadEnd, function endCallback() {
      var loadingEndTimeout = self._loadingTimeoutEndDuration;
      if (loadingEndTimeout === void 0) {
        // If we are running on a non-view object pull the default timeout
        loadingEndTimeout = Thorax.View.prototype._loadingTimeoutEndDuration;
      }

      var events = loadInfo.events,
          index = events.indexOf(object);
      if (index >= 0) {
        events.splice(index, 1);

        if (events.indexOf(object) < 0) {
          // Last callback for this particlar object, remove the bind
          object.off(loadEnd, endCallback);
        }
      }

      if (!events.length) {
        clearTimeout(loadInfo.endTimeout);
        loadInfo.endTimeout = setTimeout(function() {
          try {
            if (!events.length) {
              var run = loadInfo.run;

              if (run) {
                // Emit the end behavior, but only if there is a paired start
                end.call(self, loadInfo.background, loadInfo);
                loadInfo.trigger(loadEnd, loadInfo);
              }

              // If stopping make sure we don't run a start
              clearTimeout(loadInfo.timeout);
              loadInfo = self._loadInfo[loadCounter] = undefined;
            }
          } catch (e) {
            Thorax.onException('loadEnd', e);
          }
        }, loadingEndTimeout * 1000);
      }
    });
  };
};

/**
 * Helper method for propagating load:start events to other objects.
 *
 * Forwards load:start events that occur on `source` to `dest`.
 */
Thorax.forwardLoadEvents = function(source, dest, once) {
  function load(message, backgound, object) {
    if (once) {
      source.off(loadStart, load);
    }
    dest.trigger(loadStart, message, backgound, object);
  }
  source.on(loadStart, load);
  return {
    off: function() {
      source.off(loadStart, load);
    }
  };
};

//
// Data load event generation
//

/**
 * Mixing for generating load:start and load:end events.
 */
Thorax.mixinLoadable = function(target, useParent) {
  _.extend(target, {
    //loading config
    _loadingClassName: 'loading',
    _loadingTimeoutDuration: 0.33,
    _loadingTimeoutEndDuration: 0.10,

    // Propagates loading view parameters to the AJAX layer
    onLoadStart: function(message, background, object) {
      var that = useParent ? this.parent : this;

      // Protect against race conditions
      if (!that || !that.el) {
        return;
      }

      if (!that.nonBlockingLoad && !background && rootObject && rootObject !== this) {
        rootObject.trigger(loadStart, message, background, object);
      }
      $(that.el).addClass(that._loadingClassName);
      //used by loading helpers
      if (that._loadingCallbacks) {
        _.each(that._loadingCallbacks, function(callback) {
          callback();
        });
      }
    },
    onLoadEnd: function(/* background, object */) {
      var that = useParent ? this.parent : this;

      // Protect against race conditions
      if (!that || !that.el) {
        return;
      }

      $(that.el).removeClass(that._loadingClassName);
      //used by loading helpers
      if (that._loadingCallbacks) {
        _.each(that._loadingCallbacks, function(callback) {
          callback();
        });
      }
    }
  });
};

Thorax.mixinLoadableEvents = function(target, useParent) {
  _.extend(target, {
    loadStart: function(message, background) {
      var that = useParent ? this.parent : this;
      that.trigger(loadStart, message, background, that);
    },
    loadEnd: function() {
      var that = useParent ? this.parent : this;
      that.trigger(loadEnd, that);
    }
  });
};

Thorax.mixinLoadable(Thorax.View.prototype);
Thorax.mixinLoadableEvents(Thorax.View.prototype);


if (Thorax.HelperView) {
  Thorax.mixinLoadable(Thorax.HelperView.prototype, true);
  Thorax.mixinLoadableEvents(Thorax.HelperView.prototype, true);
}

Thorax.sync = function(method, dataObj, options) {
  var self = this,
      complete = options.complete;

  options.complete = function() {
    self._request = undefined;
    self._aborted = false;

    complete && complete.apply(this, arguments);
  };
  this._request = Backbone.sync.apply(this, arguments);

  return this._request;
};

function bindToRoute(callback, failback) {
  var fragment = Backbone.history.getFragment(),
      routeChanged = false;

  function routeHandler() {
    if (fragment === Backbone.history.getFragment()) {
      return;
    }
    routeChanged = true;
    res.cancel();
    failback && failback();
  }

  Backbone.history.on('route', routeHandler);

  function finalizer() {
    Backbone.history.off('route', routeHandler);
    if (!routeChanged) {
      callback.apply(this, arguments);
    }
  }

  var res = _.bind(finalizer, this);
  res.cancel = function() {
    Backbone.history.off('route', routeHandler);
  };

  return res;
}

function loadData(callback, failback, options) {
  if (this.isPopulated()) {
    return callback(this);
  }

  if (arguments.length === 2 && typeof failback !== 'function' && _.isObject(failback)) {
    options = failback;
    failback = false;
  }

  var self = this,
      routeChanged = false,
      successCallback = bindToRoute(_.bind(callback, self), function() {
        routeChanged = true;
        if (self._request) {
          self._aborted = true;
          self._request.abort();
        }
        failback && failback.call(self, false);
      });

  this.fetch(_.defaults({
    success: successCallback,
    error: failback && function() {
      if (!routeChanged) {
        failback.apply(self, [true].concat(_.toArray(arguments)));
      }
    },
    complete: function() {
      successCallback.cancel();
    }
  }, options));
}

function fetchQueue(options, $super) {
  if (options.resetQueue) {
    // WARN: Should ensure that loaders are protected from out of band data
    //    when using this option
    this.fetchQueue = undefined;
  }

  if (!this.fetchQueue) {
    // Kick off the request
    this.fetchQueue = [options];
    options = _.defaults({
      success: flushQueue(this, this.fetchQueue, 'success'),
      error: flushQueue(this, this.fetchQueue, 'error'),
      complete: flushQueue(this, this.fetchQueue, 'complete')
    }, options);
    $super.call(this, options);
  } else {
    // Currently fetching. Queue and process once complete
    this.fetchQueue.push(options);
  }
}

function flushQueue(self, fetchQueue, handler) {
  return function() {
    var args = arguments;

    // Flush the queue. Executes any callback handlers that
    // may have been passed in the fetch options.
    _.each(fetchQueue, function(options) {
      if (options[handler]) {
        options[handler].apply(this, args);
      }
    }, this);

    // Reset the queue if we are still the active request
    if (self.fetchQueue === fetchQueue) {
      self.fetchQueue = undefined;
    }
  };
}

var klasses = [];
Thorax.Model && klasses.push(Thorax.Model);
Thorax.Collection && klasses.push(Thorax.Collection);

_.each(klasses, function(DataClass) {
  var $fetch = DataClass.prototype.fetch;
  Thorax.mixinLoadableEvents(DataClass.prototype, false);
  _.extend(DataClass.prototype, {
    sync: Thorax.sync,

    fetch: function(options) {
      options = options || {};

      var self = this,
          complete = options.complete;

      options.complete = function() {
        complete && complete.apply(this, arguments);
        self.loadEnd();
      };
      self.loadStart(undefined, options.background);
      return fetchQueue.call(this, options || {}, $fetch);
    },

    load: function(callback, failback, options) {
      if (arguments.length === 2 && typeof failback !== 'function') {
        options = failback;
        failback = false;
      }

      options = options || {};
      if (!options.background && !this.isPopulated() && rootObject) {
        // Make sure that the global scope sees the proper load events here
        // if we are loading in standalone mode
        Thorax.forwardLoadEvents(this, rootObject, true);
      }

      loadData.call(this, callback, failback, options);
    }
  });
});

Thorax.Util.bindToRoute = bindToRoute;

if (Thorax.Router) {
  Thorax.Router.bindToRoute = Thorax.Router.prototype.bindToRoute = bindToRoute;
}

// Propagates loading view parameters to the AJAX layer
Thorax.View.prototype._modifyDataObjectOptions = function(dataObject, options) {
  options.ignoreErrors = this.ignoreFetchError;
  options.background = this.nonBlockingLoad;
  return options;
};

Thorax.HelperView.prototype._modifyDataObjectOptions = function(dataObject, options) {
  options.ignoreErrors = this.parent.ignoreFetchError;
  options.background = this.parent.nonBlockingLoad;
  return options;
};

inheritVars.collection.loading = function() {
  var loadingView = this.loadingView,
      loadingTemplate = this.loadingTemplate,
      loadingPlacement = this.loadingPlacement;
  //add "loading-view" and "loading-template" options to collection helper
  if (loadingView || loadingTemplate) {
    var callback = Thorax.loadHandler(_.bind(function() {
      var item;
      if (this.collection.length === 0) {
        this.$el.empty();
      }
      if (loadingView) {
        var instance = Thorax.Util.getViewInstance(loadingView);
        this._addChild(instance);
        if (loadingTemplate) {
          instance.render(loadingTemplate);
        } else {
          instance.render();
        }
        item = instance;
      } else {
        item = this.renderTemplate(loadingTemplate);
      }
      var index = loadingPlacement
        ? loadingPlacement.call(this)
        : this.collection.length
      ;
      this.appendItem(item, index);
      this.$el.children().eq(index).attr('data-loading-element', this.collection.cid);
    }, this), _.bind(function() {
      this.$el.find('[data-loading-element="' + this.collection.cid + '"]').remove();
    }, this),
    this.collection);

    this.listenTo(this.collection, 'load:start', callback);
  }
};

if (typeof collectionOptionNames !== 'undefined') {
  collectionOptionNames['loading-template'] = 'loadingTemplate';
  collectionOptionNames['loading-view'] = 'loadingView';
  collectionOptionNames['loading-placement'] = 'loadingPlacement';
}

Thorax.View.on({
  'load:start': Thorax.loadHandler(
      function(message, background, object) {
        this.onLoadStart(message, background, object);
      },
      function(background, object) {
        this.onLoadEnd(object);
      }),

  collection: {
    'load:start': function(message, background, object) {
      this.trigger(loadStart, message, background, object);
    }
  },
  model: {
    'load:start': function(message, background, object) {
      this.trigger(loadStart, message, background, object);
    }
  }
});

;;
Handlebars.registerViewHelper('loading', function(view) {
  var _render = view.render;
  view.render = function() {
    if (view.parent.$el.hasClass(view.parent._loadingClassName)) {
      return _render.call(this, view.fn);
    } else {
      return _render.call(this, view.inverse);
    }
  };
  var callback = _.bind(view.render, view);
  view.parent._loadingCallbacks = view.parent._loadingCallbacks || [];
  view.parent._loadingCallbacks.push(callback);
  view.on('destroyed', function() {
    view.parent._loadingCallbacks = _.without(view.parent._loadingCallbacks, callback);
  });
  view.render();
});

;;
var isIE = (/msie [\w.]+/).exec(navigator.userAgent.toLowerCase());

// IE will lose a reference to the elements if view.el.innerHTML = '';
// If they are removed one by one the references are not lost.
// For instance a view's childrens' `el`s will be lost if the view
// sets it's `el.innerHTML`.
if (isIE) {
  Thorax.View.on('before:append', function() {
    if (this._renderCount > 0) {
      _.each(this._elementsByCid, function(element) {
        $(element).remove();
      });
      _.each(this.children, function(child) {
        child.$el.remove();
      });
    }
  });
}

;;


})();