(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"),

                color : this.get("color"),

                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,

                color : this.get("color"),

                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({

        schemaVersion : "1",

        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.schemaVersion;

          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);

            json.schema_version = this.schemaVersion;

            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 + ")";

                        options.description = options.description || "";