(function(root) {

    'use strict';

    var Backbone = root.Backbone;

    var Models = root.Rkns.Models = {};

    Models.getUID = function(obj) {

        var guid = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'

            .replace(/[xy]/g,

                     function(c) {

                         var r = Math.random() * 16 | 0, v = c === 'x' ? r

                             : (r & 0x3 | 0x8);

                         return v.toString(16);

                     });

        if (typeof obj !== 'undefined') {

            return obj.type + '-' + guid;

        }

        else {

            return guid;

        }

    };

    var RenkanModel = Backbone.RelationalModel.extend({

        idAttribute : '_id',

        constructor : function(options) {

            if (typeof options !== 'undefined') {

                options._id = options._id || options.id || Models.getUID(this);

                options.title = options.title || '';

                options.description = options.description || '';

                options.uri = options.uri || '';

                if (typeof this.prepare === 'function') {

                    options = this.prepare(options);

                }

            }

            Backbone.RelationalModel.prototype.constructor.call(this, options);

        },

        validate : function() {

            if (!this.type) {

                return 'object has no type';

            }

        },

        addReference : function(_options, _propName, _list, _id, _default) {

            var _element = _list.get(_id);

            if (typeof _element === 'undefined' &&

                typeof _default !== 'undefined') {

                _options[_propName] = _default;

            }

            else {

                _options[_propName] = _element;

            }

        }

    });

    // USER

    var User = Models.User = RenkanModel.extend({

        type : 'user',

        prepare : function(options) {

            options.color = options.color || '#666666';

            return options;

        },

        toJSON : function() {

            return {

                _id : this.get('_id'),

                title : this.get('title'),

                uri : this.get('uri'),

                description : this.get('description'),

                color : this.get('color')

            };

        }

    });

    // NODE

    var Node = Models.Node = RenkanModel.extend({

        type : 'node',

        relations : [ {

            type : Backbone.HasOne,

            key : 'created_by',

            relatedModel : User

        } ],

        prepare : function(options) {

            var project = options.project;

            this.addReference(options, 'created_by', project.get('users'),

                              options.created_by, project.current_user);

            options.description = options.description || '';

            return options;

        },

        toJSON : function() {

            return {

                _id : this.get('_id'),

                title : this.get('title'),

                uri : this.get('uri'),

                description : this.get('description'),

                position : this.get('position'),

                image : this.get('image'),

                style : this.get('style'),

                created_by : this.get('created_by') ? this.get('created_by')

                    .get('_id') : null,

                size : this.get('size'),

                clip_path : this.get('clip_path'),

                shape : this.get('shape'),

                type : this.get('type')

            };

        }

    });

    // EDGE

    var Edge = Models.Edge = RenkanModel.extend({

        type : 'edge',

        relations : [ {

            type : Backbone.HasOne,

            key : 'created_by',

            relatedModel : User

        }, {

            type : Backbone.HasOne,

            key : 'from',

            relatedModel : Node

        }, {

            type : Backbone.HasOne,

            key : 'to',

            relatedModel : Node

        } ],

        prepare : function(options) {

            var project = options.project;

            this.addReference(options, 'created_by', project.get('users'),

                              options.created_by, project.current_user);

            this.addReference(options, 'from', project.get('nodes'),

                              options.from);

            this.addReference(options, 'to', project.get('nodes'), options.to);

            return options;

        },

        toJSON : function() {

            return {

                _id : this.get('_id'),

                title : this.get('title'),

                uri : this.get('uri'),

                description : this.get('description'),

                from : this.get('from') ? this.get('from').get('_id') : null,

                to : this.get('to') ? this.get('to').get('_id') : null,

                style : this.get('style'),

                created_by : this.get('created_by') ? this.get('created_by')

                    .get('_id') : null

            };

        }

    });

    // View

    var View = Models.View = RenkanModel.extend({

        type : 'view',

        relations : [ {

            type : Backbone.HasOne,

            key : 'created_by',

            relatedModel : User

        } ],

        prepare : function(options) {

            var project = options.project;

            this.addReference(options, 'created_by', project.get('users'),

                              options.created_by, project.current_user);

            options.description = options.description || '';

            if (typeof options.offset !== 'undefined') {

                var offset = {};

                if (Array.isArray(options.offset)) {

                    offset.x = options.offset[0];

                    offset.y = options.offset.length > 1 ? options.offset[1]

                        : options.offset[0];

                }

                else if (options.offset.x != null) {

                    offset.x = options.offset.x;

                    offset.y = options.offset.y;

                }

                options.offset = offset;

            }

            return options;

        },

        toJSON : function() {

            return {

                _id : this.get('_id'),

                zoom_level : this.get('zoom_level'),

                offset : this.get('offset'),

                title : this.get('title'),

                description : this.get('description'),

                created_by : this.get('created_by') ? this.get('created_by')

                    .get('_id') : null,

                hidden_nodes: this.get('hidden_nodes')

                // Don't need project id

            };

        }

    });

    // PROJECT

    var Project = Models.Project = RenkanModel.extend({

        schema_version : '2',

        type : 'project',

        blacklist : [ 'saveStatus', 'loadingStatus'],

        relations : [ {

            type : Backbone.HasMany,

            key : 'users',

            relatedModel : User,

            reverseRelation : {

                key : 'project',

                includeInJSON : '_id'

            }

        }, {

            type : Backbone.HasMany,

            key : 'nodes',

            relatedModel : Node,

            reverseRelation : {

                key : 'project',

                includeInJSON : '_id'

            }

        }, {

            type : Backbone.HasMany,

            key : 'edges',

            relatedModel : Edge,

            reverseRelation : {

                key : 'project',

                includeInJSON : '_id'

            }

        }, {

            type : Backbone.HasMany,

            key : 'views',

            relatedModel : View,

            reverseRelation : {

                key : 'project',

                includeInJSON : '_id'

            }

        } ],

        addUser : function(_props, _options) {

            _props.project = this;

            var _user = User.findOrCreate(_props);

            this.get('users').push(_user, _options);

            return _user;

        },

        addNode : function(_props, _options) {

            _props.project = this;

            var _node = Node.findOrCreate(_props);

            this.get('nodes').push(_node, _options);

            return _node;

        },

        addEdge : function(_props, _options) {

            _props.project = this;

            var _edge = Edge.findOrCreate(_props);

            this.get('edges').push(_edge, _options);

            return _edge;

        },

        addView : function(_props, _options) {

            _props.project = this;

            // TODO: check if need to replace with create only

            var _view = View.findOrCreate(_props);

            // TODO: Should we remember only one view?

            this.get('views').push(_view, _options);

            return _view;

        },

        removeNode : function(_model) {

            this.get('nodes').remove(_model);

        },

        removeEdge : function(_model) {

            this.get('edges').remove(_model);

        },

        validate : function(options) {

            var _project = this;

            _.each(

                [].concat(options.users, options.nodes, options.edges,options.views),

                function(_item) {

                    if (_item) {

                        _item.project = _project;

                    }

                }

            );

        },

        getSchemaVersion : function(data) {

            var t = data;

            if(typeof(t) === 'undefined') {

                t = this;

            }

            var version = t.schema_version;

            if(!version) {

                return 1;

            }

            else {

                return version;

            }

        },

        // Add event handler to remove edges when a node is removed

        initialize : function() {

            var _this = this;

            this.on('remove:nodes', function(_node) {

                _this.get('edges').remove(

                    _this.get('edges').filter(

                        function(_edge) {

                            return _edge.get('from') === _node ||

                                _edge.get('to') === _node;

                        }));

            });

        },

        toJSON : function() {

            var json = _.clone(this.attributes);

            for ( var attr in json) {

                if ((json[attr] instanceof Backbone.Model) ||

                    (json[attr] instanceof Backbone.Collection) ||

                    (json[attr] instanceof RenkanModel)) {

                    json[attr] = json[attr].toJSON();

                }

            }

            return _.omit(json, this.blacklist);

        }

    });

    var RosterUser = Models.RosterUser = Backbone.Model

        .extend({

            type : 'roster_user',

            idAttribute : '_id',

            constructor : function(options) {

                if (typeof options !== 'undefined') {

                    options._id = options._id ||

                        options.id ||

                        Models.getUID(this);

                    options.title = options.title || '(untitled ' + this.type + ')';