//     Backbone.js 1.2.3

//     (c) 2010-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors

//     Backbone may be freely distributed under the MIT license.

//     For all details and documentation:

//     http://backbonejs.org

(function(factory) {

  // Establish the root object, `window` (`self`) in the browser, or `global` on the server.

  // We use `self` instead of `window` for `WebWorker` support.

  var root = (typeof self == 'object' && self.self == self && self) ||

            (typeof global == 'object' && global.global == global && global);

  // Set up Backbone appropriately for the environment. Start with AMD.

  if (typeof define === 'function' && define.amd) {

    define(['underscore', 'jquery', 'exports'], function(_, $, exports) {

      // Export global even in AMD case in case this script is loaded with

      // others that may still expect a global Backbone.

      root.Backbone = factory(root, exports, _, $);

    });

  // Next for Node.js or CommonJS. jQuery may not be needed as a module.

  } else if (typeof exports !== 'undefined') {

    var _ = require('underscore'), $;

    try { $ = require('jquery'); } catch(e) {}

    factory(root, exports, _, $);

  // Finally, as a browser global.

  } else {

    root.Backbone = factory(root, {}, root._, (root.jQuery || root.Zepto || root.ender || root.$));

  }

}(function(root, Backbone, _, $) {

  // Initial Setup

  // -------------

  // Save the previous value of the `Backbone` variable, so that it can be

  // restored later on, if `noConflict` is used.

  var previousBackbone = root.Backbone;

  // Create a local reference to a common array method we'll want to use later.

  var slice = Array.prototype.slice;

  // Current version of the library. Keep in sync with `package.json`.

  Backbone.VERSION = '1.2.3';

  // For Backbone's purposes, jQuery, Zepto, Ender, or My Library (kidding) owns

  // the `$` variable.

  Backbone.$ = $;

  // Runs Backbone.js in *noConflict* mode, returning the `Backbone` variable

  // to its previous owner. Returns a reference to this Backbone object.

  Backbone.noConflict = function() {

    root.Backbone = previousBackbone;

    return this;

  };

  // Turn on `emulateHTTP` to support legacy HTTP servers. Setting this option

  // will fake `"PATCH"`, `"PUT"` and `"DELETE"` requests via the `_method` parameter and

  // set a `X-Http-Method-Override` header.

  Backbone.emulateHTTP = false;

  // Turn on `emulateJSON` to support legacy servers that can't deal with direct

  // `application/json` requests ... this will encode the body as

  // `application/x-www-form-urlencoded` instead and will send the model in a

  // form param named `model`.

  Backbone.emulateJSON = false;

  // Proxy Backbone class methods to Underscore functions, wrapping the model's

  // `attributes` object or collection's `models` array behind the scenes.

  //

  // collection.filter(function(model) { return model.get('age') > 10 });

  // collection.each(this.addView);

  //

  // `Function#apply` can be slow so we use the method's arg count, if we know it.

  var addMethod = function(length, method, attribute) {

    switch (length) {

      case 1: return function() {

        return _[method](this[attribute]);

      };

      case 2: return function(value) {

        return _[method](this[attribute], value);

      };

      case 3: return function(iteratee, context) {

        return _[method](this[attribute], cb(iteratee, this), context);

      };

      case 4: return function(iteratee, defaultVal, context) {

        return _[method](this[attribute], cb(iteratee, this), defaultVal, context);

      };

      default: return function() {

        var args = slice.call(arguments);

        args.unshift(this[attribute]);

        return _[method].apply(_, args);

      };

    }

  };

  var addUnderscoreMethods = function(Class, methods, attribute) {

    _.each(methods, function(length, method) {

      if (_[method]) Class.prototype[method] = addMethod(length, method, attribute);

    });

  };

  // Support `collection.sortBy('attr')` and `collection.findWhere({id: 1})`.

  var cb = function(iteratee, instance) {

    if (_.isFunction(iteratee)) return iteratee;

    if (_.isObject(iteratee) && !instance._isModel(iteratee)) return modelMatcher(iteratee);

    if (_.isString(iteratee)) return function(model) { return model.get(iteratee); };

    return iteratee;

  };

  var modelMatcher = function(attrs) {

    var matcher = _.matches(attrs);

    return function(model) {

      return matcher(model.attributes);

    };

  };

  // Backbone.Events

  // ---------------

  // A module that can be mixed in to *any object* in order to provide it with

  // a custom event channel. You may bind a callback to an event with `on` or

  // remove with `off`; `trigger`-ing an event fires all callbacks in

  // succession.

  //

  //     var object = {};

  //     _.extend(object, Backbone.Events);

  //     object.on('expand', function(){ alert('expanded'); });

  //     object.trigger('expand');

  //

  var Events = Backbone.Events = {};

  // Regular expression used to split event strings.

  var eventSplitter = /\s+/;

  // Iterates over the standard `event, callback` (as well as the fancy multiple

  // space-separated events `"change blur", callback` and jQuery-style event

  // maps `{event: callback}`).

  var eventsApi = function(iteratee, events, name, callback, opts) {

    var i = 0, names;

    if (name && typeof name === 'object') {

      // Handle event maps.

      if (callback !== void 0 && 'context' in opts && opts.context === void 0) opts.context = callback;

      for (names = _.keys(name); i < names.length ; i++) {

        events = eventsApi(iteratee, events, names[i], name[names[i]], opts);

      }

    } else if (name && eventSplitter.test(name)) {

      // Handle space separated event names by delegating them individually.

      for (names = name.split(eventSplitter); i < names.length; i++) {

        events = iteratee(events, names[i], callback, opts);

      }

    } else {

      // Finally, standard events.

      events = iteratee(events, name, callback, opts);

    }

    return events;

  };

  // Bind an event to a `callback` function. Passing `"all"` will bind

  // the callback to all events fired.

  Events.on = function(name, callback, context) {

    return internalOn(this, name, callback, context);

  };

  // Guard the `listening` argument from the public API.

  var internalOn = function(obj, name, callback, context, listening) {

    obj._events = eventsApi(onApi, obj._events || {}, name, callback, {

        context: context,

        ctx: obj,

        listening: listening

    });

    if (listening) {

      var listeners = obj._listeners || (obj._listeners = {});

      listeners[listening.id] = listening;

    }

    return obj;

  };

  // Inversion-of-control versions of `on`. Tell *this* object to listen to

  // an event in another object... keeping track of what it's listening to

  // for easier unbinding later.

  Events.listenTo =  function(obj, name, callback) {

    if (!obj) return this;

    var id = obj._listenId || (obj._listenId = _.uniqueId('l'));

    var listeningTo = this._listeningTo || (this._listeningTo = {});

    var listening = listeningTo[id];

    // This object is not listening to any other events on `obj` yet.

    // Setup the necessary references to track the listening callbacks.

    if (!listening) {

      var thisId = this._listenId || (this._listenId = _.uniqueId('l'));

      listening = listeningTo[id] = {obj: obj, objId: id, id: thisId, listeningTo: listeningTo, count: 0};

    }

    // Bind callbacks on obj, and keep track of them on listening.

    internalOn(obj, name, callback, this, listening);

    return this;

  };

  // The reducing API that adds a callback to the `events` object.

  var onApi = function(events, name, callback, options) {

    if (callback) {

      var handlers = events[name] || (events[name] = []);

      var context = options.context, ctx = options.ctx, listening = options.listening;

      if (listening) listening.count++;

      handlers.push({ callback: callback, context: context, ctx: context || ctx, listening: listening });

    }

    return events;

  };

  // Remove one or many callbacks. If `context` is null, removes all

  // callbacks with that function. If `callback` is null, removes all

  // callbacks for the event. If `name` is null, removes all bound

  // callbacks for all events.

  Events.off =  function(name, callback, context) {

    if (!this._events) return this;

    this._events = eventsApi(offApi, this._events, name, callback, {

        context: context,

        listeners: this._listeners

    });

    return this;

  };

  // Tell this object to stop listening to either specific events ... or

  // to every object it's currently listening to.

  Events.stopListening =  function(obj, name, callback) {

    var listeningTo = this._listeningTo;

    if (!listeningTo) return this;

    var ids = obj ? [obj._listenId] : _.keys(listeningTo);

    for (var i = 0; i < ids.length; i++) {

      var listening = listeningTo[ids[i]];

      // If listening doesn't exist, this object is not currently

      // listening to obj. Break out early.

      if (!listening) break;

      listening.obj.off(name, callback, this);

    }

    if (_.isEmpty(listeningTo)) this._listeningTo = void 0;

    return this;

  };

  // The reducing API that removes a callback from the `events` object.

  var offApi = function(events, name, callback, options) {

    if (!events) return;

    var i = 0, listening;

    var context = options.context, listeners = options.listeners;

    // Delete all events listeners and "drop" events.

    if (!name && !callback && !context) {

      var ids = _.keys(listeners);

      for (; i < ids.length; i++) {

        listening = listeners[ids[i]];

        delete listeners[listening.id];

        delete listening.listeningTo[listening.objId];

      }

      return;

    }

    var names = name ? [name] : _.keys(events);

    for (; i < names.length; i++) {

      name = names[i];

      var handlers = events[name];

      // Bail out if there are no events stored.

      if (!handlers) break;

      // Replace events if there are any remaining.  Otherwise, clean up.

      var remaining = [];

      for (var j = 0; j < handlers.length; j++) {

        var handler = handlers[j];

        if (

          callback && callback !== handler.callback &&

            callback !== handler.callback._callback ||

              context && context !== handler.context

        ) {

          remaining.push(handler);

        } else {

          listening = handler.listening;

          if (listening && --listening.count === 0) {

            delete listeners[listening.id];

            delete listening.listeningTo[listening.objId];

          }

        }

      }

      // Update tail event if the list has any events.  Otherwise, clean up.

      if (remaining.length) {

        events[name] = remaining;

      } else {

        delete events[name];

      }

    }

    if (_.size(events)) return events;

  };

  // Bind an event to only be triggered a single time. After the first time

  // the callback is invoked, its listener will be removed. If multiple events

  // are passed in using the space-separated syntax, the handler will fire

  // once for each event, not once for a combination of all events.

  Events.once =  function(name, callback, context) {

    // Map the event into a `{event: once}` object.

    var events = eventsApi(onceMap, {}, name, callback, _.bind(this.off, this));

    return this.on(events, void 0, context);

  };

  // Inversion-of-control versions of `once`.

  Events.listenToOnce =  function(obj, name, callback) {

    // Map the event into a `{event: once}` object.

    var events = eventsApi(onceMap, {}, name, callback, _.bind(this.stopListening, this, obj));

    return this.listenTo(obj, events);

  };

  // Reduces the event callbacks into a map of `{event: onceWrapper}`.

  // `offer` unbinds the `onceWrapper` after it has been called.

  var onceMap = function(map, name, callback, offer) {

    if (callback) {

      var once = map[name] = _.once(function() {

        offer(name, once);

        callback.apply(this, arguments);

      });

      once._callback = callback;

    }

    return map;

  };