// Backbone React Component
// ========================
//
//     Backbone.React.Component v0.7.0
//
//     (c) 2014 "Magalhas" José Magalhães <magalhas@gmail.com>
//     Backbone.React.Component can be freely distributed under the MIT license.
//
//
// `Backbone.React.Component` is a mixin that glues [Backbone](http://backbonejs.org/)
// models and collections into [React](http://facebook.github.io/react/) components.
//
// When the component is mounted, a wrapper starts listening to models and
// collections changes to automatically set your component props and achieve UI
// binding through reactive updates.
//
//
//
// Basic Usage
//
//     var MyComponent = React.createClass({
//       mixins: [Backbone.React.Component.mixin],
//       render: function () {
//         return <div>{this.props.foo}</div>;
//       }
//     });
//     var model = new Backbone.Model({foo: 'bar'});
//     React.renderComponent(<MyComponent model={model} />, document.body);

'use strict';
(function (root, factory) {
  // Universal module definition
  if (typeof define === 'function' && define.amd)
    define(['react', 'backbone', 'underscore'], factory);
  else if (typeof module !== 'undefined' && module.exports) {
    var React = require('react');
    var Backbone = require('backbone');
    var _ = require('underscore');
    module.exports = factory(React, Backbone, _);
  } else
    factory(root.React, root.Backbone, root._);
}(this, function (React, Backbone, _) {
  !Backbone.React && (Backbone.React = {});
  !Backbone.React.Component && (Backbone.React.Component = {});
  // Mixin used in all component instances. Exported through `Backbone.React.Component.mixin`.
  var mixin = Backbone.React.Component.mixin = {
    // Sets `this.el` and `this.$el` when the component mounts.
    componentDidMount: function () {
      this.setElement(this.getDOMNode());
    },
    // Sets `this.el` and `this.$el` when the component updates.
    componentDidUpdate: function () {
      this.setElement(this.getDOMNode());
    },
    // When the component mounts, instance a `Wrapper` to take care
    // of models and collections binding with `this.props`.
    componentWillMount: function () {
      if (!this.wrapper) {
        this.wrapper = new Wrapper(this, this.props);
      }
    },
    // When the component unmounts, dispose listeners and delete
    // `this.wrapper` reference.
    componentWillUnmount: function () {
      if (this.wrapper) {
        this.wrapper.stopListening();
        delete this.wrapper;
      }
    },
    // In order to allow passing nested models as reference we filter
    // `nextProps.model`.
    componentWillReceiveProps: function (nextProps) {
      var model = nextProps.model;
      if (this.wrapper.model && model) {
        delete nextProps.model;
        if (this.wrapper.model.attributes) {
          this.wrapper.setProps(model, void 0, nextProps);
        } else {
          for (var key in model) {
            this.wrapper.setProps(model[key], key, nextProps);
          }
        }
      }
    },
    // Shortcut to `this.$el.find`. Inspired by `Backbone.View`.
    $: function () {
      return this.$el && this.$el.find.apply(this.$el, arguments);
    },
    // Crawls up to the owner of the component searching for a collection.
    getCollection: function () {
      var owner = this;
      var lookup = owner.wrapper;
      while (!lookup.collection) {
        owner = owner._owner;
        if (!owner) {
          throw new Error('Collection not found');
        }
        lookup = owner.wrapper;
      }
      return lookup.collection;
    },
    // Crawls up to the owner of the component searching for a model.
    getModel: function () {
      var owner = this;
      var lookup = owner.wrapper;
      while (!lookup.model) {
        owner = owner._owner;
        if (!owner) {
          throw new Error('Model not found');
        }
        lookup = owner.wrapper;
      }
      return lookup.model;
    },
    // Crawls `this._owner` recursively until it finds the owner of `this`
    // component. In case of being a parent component (no owners) it returns itself.
    getOwner: function () {
      var owner = this;
      while (owner._owner) {
        owner = owner._owner;
      }
      return owner;
    },
    // Sets a DOM element to render/mount this component on this.el and this.$el.
    setElement: function (el) {
      if (el && Backbone.$ && el instanceof Backbone.$) {
        if (el.length > 1) {
          throw new Error('You can only assign one element to a component');
        }
        this.el = el[0];
        this.$el = el;
      } else if (el) {
        this.el = el;
        Backbone.$ && (this.$el = Backbone.$(el));
      }
      return this;
    }
  };
  // Binds models and collections to a `React.Component`. It mixes `Backbone.Events`.
  function Wrapper (component, props) {
    props = props || {};
    var model = props.model, collection = props.collection;
    // Check if `props.model` is a `Backbone.Model` or an hashmap of them
    if (typeof model !== 'undefined' && (model.attributes ||
        typeof model === 'object' && _.values(model)[0].attributes)) {
      delete props.model;
      // The model(s) bound to this component
      this.model = model;
      // Set model(s) attributes on `props` for the first render
      this.setPropsBackbone(model, void 0, props);
    }
    // Check if `props.collection` is a `Backbone.Collection` or an hashmap of them
    if (typeof collection !== 'undefined' && (collection.models ||
        typeof collection === 'object' && _.values(collection)[0].models)) {
      delete props.collection;
      // The collection(s) bound to this component
      this.collection = collection;
      // Set collection(s) models on props for the first render
      this.setPropsBackbone(collection, void 0, props);
    }
    // 1:1 relation with the `component`
    this.component = component;
    // Start listeners if this is a root node and if there's DOM
    if (!component._owner && typeof document !== 'undefined') {
      this.startModelListeners();
      this.startCollectionListeners();
    }
  }
  // Mixing `Backbone.Events` into `Wrapper.prototype`
  _.extend(Wrapper.prototype, Backbone.Events, {
    // Sets `this.props` when a model/collection request results in error. It delegates
    // to `this.setProps`. It listens to `Backbone.Model#error` and `Backbone.Collection#error`.
    onError: function (modelOrCollection, res, options) {
      // Set props only if there's no silent option
      if (!options.silent)
        this.setProps({
          isRequesting: false,
          hasError: true,
          error: res
        });
    },
    // Sets `this.props` when a model/collection request starts. It delegates to
    // `this.setProps`. It listens to `Backbone.Model#request` and `Backbone.Collection#request`.
    onRequest: function (modelOrCollection, xhr, options) {
      // Set props only if there's no silent option
      if (!options.silent)
        this.setProps({
          isRequesting: true,
          hasError: false
        });
    },
    // Sets `this.props` when a model/collection syncs. It delegates to `this.setProps`.
    // It listens to `Backbone.Model#sync` and `Backbone.Collection#sync`
    onSync: function (modelOrCollection, res, options) {
      // Set props only if there's no silent option
      if (!options.silent)
        this.setProps({isRequesting: false});
    },
    // Used internally to set `this.collection` or `this.model` on `this.props`. Delegates to
    // `this.setProps`. It listens to `Backbone.Collection` events such as `add`, `remove`,
    // `change`, `sort`, `reset` and to `Backbone.Model` `change`.
    setPropsBackbone: function (modelOrCollection, key, target) {
      if (!(modelOrCollection.models || modelOrCollection.attributes)) {
        for (key in modelOrCollection)
            this.setPropsBackbone(modelOrCollection[key], key, target);
        return;
      }
      this.setProps.apply(this, arguments);
    },
    // Sets a model, collection or object into props by delegating to `this.setProps`.
    setProps: function (modelOrCollection, key, target) {
      var props = {};
      var newProps = modelOrCollection.toJSON ? modelOrCollection.toJSON() : modelOrCollection;

      if (key) {
        props[key] = newProps;
      } else if (modelOrCollection instanceof Backbone.Collection) {
        props.collection = newProps;
      } else {
        props = newProps;
      }

      if (target) {
        _.extend(target, props);
      } else {
        this.nextProps = _.extend(this.nextProps || {}, props);
        _.defer(_.bind(function () {
          if (this.nextProps) {
            this.component && this.component.setProps(this.nextProps);
            delete this.nextProps;
          }
        }, this));
      }
    },
    // Binds the component to any collection changes.
    startCollectionListeners: function (collection, key) {
      if (!collection) collection = this.collection;
      if (collection) {
        if (collection.models)
          this
            .listenTo(collection, 'add remove change sort reset',
              _.partial(this.setPropsBackbone, collection, key, void 0))
            .listenTo(collection, 'error', this.onError)
            .listenTo(collection, 'request', this.onRequest)
            .listenTo(collection, 'sync', this.onSync);
        else if (typeof collection === 'object')
          for (key in collection)
            if (collection.hasOwnProperty(key))
              this.startCollectionListeners(collection[key], key);
      }
    },
    // Binds the component to any model changes.
    startModelListeners: function (model, key) {
      if (!model) model = this.model;
      if (model) {
        if (model.attributes)
          this
            .listenTo(model, 'change',
              _.partial(this.setPropsBackbone, model, key, void 0))
            .listenTo(model, 'error', this.onError)
            .listenTo(model, 'request', this.onRequest)
            .listenTo(model, 'sync', this.onSync);
        else if (typeof model === 'object')
          for (key in model)
            this.startModelListeners(model[key], key);
      }
    }
  });

  // Expose `Backbone.React.Component.mixin`.
  return Backbone.React.Component.mixin;
}));
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