/**
 * Offline library for storing graphics related to an Edit Task.
 * Currently works with Points, Polylines and Polygons. Also provides automatic
 * online/offline validation.
 *
 * Automatically attempts to reconnect. As soon as a connection is made updates are submitted
 * and the localStorage is deleted upon successful update.
 *
 * NOTE: Hooks for listeners that updates were successful/unsuccessful should be added in
 * _handleRestablishedInternet()
 *
 * NOTE: Currently designed to work with feature services that have an ObjectId field
 *
 * <b>Dependencies:</b> ArcGIS JavaScript API and Hydrate.js: https://github.com/nanodeath/HydrateJS
 * <b>Limitations:</b> does not currently store infoTemplate and symbol properties
 * <b>More info:</b> http://www.w3.org/TR/webstorage/
 * @version 0.1
 * @author Andy Gup (@agup)
 * @param map
 * @type {*|{}}
 */
var getScriptURL = (function() {
    var scripts = document.getElementsByTagName('script');
    var index = scripts.length - 1;
    var myScript = scripts[index];
    return function() { return myScript.src; };
})();

var OfflineStore = function(/* Map */ map) {
    this.layers = []; //An array of all feature layers
    this.utils = null;
    this.map = map;

    if(map != null) {
        this.map.offlineStore = this
    }
    else{
        console.log("map is null")
        throw("map is null");
    }

    /**
     * Public ENUMs. Immutable reference values.
     * @type {Object}
     * @returns {String}
     * @private
     */
    this.enum = (function(){
        var values = {
            ADD : "add",
            UPDATE : "update",
            DELETE : "delete"
        }
        return values;
    });

    /**
     * Private Local ENUMs (Constants)
     * Contains required configuration info.
     * @type {Object}
     * @returns {*}
     * @private
     */
    this._localEnum = (function(){
        var values = {
            /**
             * Tracks pending changes that have not been submitted to server and therefore do not have a UID yet
             */
            STORAGE_KEY : "___EsriOfflineStore___",
            /**
             * Index for tracking each action (add, delete, update) in local store after it has been completed
             */
            INDEX_KEY : "___EsriOfflineIndex___",
            /**
             * Most browsers offer default storage of ~5MB. This gives you the option to set a threshold.
             */
            LOCAL_STORAGE_MAX_LIMIT : 4.75 /* MB */,
            /* A unique token for tokenizing stringified localStorage values */
            TOKEN : "|||",
            EDIT_EVENT_DUPLICATE: "duplicateEditEvent",
            INTERNET_STATUS_EVENT: "internetStatusChangeEvent",
            INDEX_UPDATE_EVENT: "indexUpdateEvent",
            REQUIRED_LIBS : [
                "Hydrate.js",
                "OfflineUtils.js",
                "../../vendor/offline/offline.min.js"
            ]
        }
        return values;
    });

    /**
     * Model for handle vertices editing
     * @param graphic
     * @param layer
     */
    this.verticesObject = function(/* Graphic */ graphic, /* FeatureLayer */ layer){
        this.graphic = graphic;
        this.layer = layer;
    }

    this._hydrate = null;
    this._reestablishedInternetListener = null;

    //////////////////////////
    ///
    /// PUBLIC methods
    ///
    //////////////////////////

    /**
     * Conditionally attempts to send an edit request to ArcGIS Server.
     * @param graphic Required
     * @param layer Required
     * @param enumValue Required
     * @param callback Recommended.
     */
    this.applyEdits = function(/* Graphic */ graphic,/* FeatureLayer */ layer, /* String */ enumValue, callback){
        var internet = this.getInternet();
        this._applyEdits(internet,graphic,layer,enumValue, callback);
    }

    /**
     * Public method for retrieving all items in the temporary localStore.
     * This request does not return the index information. For that use getLocalStoreIndex().
     * @returns {Array} Graphics
     */
    this.getStore = function(){
        var graphicsArr = null;
        var data = localStorage.getItem(this._localEnum().STORAGE_KEY);
        if(data != null){
            graphicsArr = [];
            var split = data.split(this._localEnum().TOKEN);
            for(var property in split){
                var item = split[property];
                if(typeof item !== "undefined" && item.length > 0 && item !== null && item != ""){
                    var graphic = this._deserializeGraphic(item);
                    graphicsArr.push( graphic );
                }
            }
        }
        return graphicsArr;
    }

    /**
     * Provides a list of all localStorage items that have been either
     * added, deleted or updated.
     * @returns {Array}
     */
    this.getLocalStoreIndex = function(){
        var localStore = localStorage.getItem(this._localEnum().INDEX_KEY);
        return localStore != null ? localStore.split(this._localEnum().TOKEN) : null;
    }

    /**
     * Determines total storage used for this domain.
     * NOTE: The index does take up storage space. Even if the offlineStore
     * is deleted, you will still see some space taken up by the index.
     * @returns Number MB's
     */
    this.getlocalStorageUsed = function(){
        //IE hack
        if(window.localStorage.hasOwnProperty("remainingspace")){
            //http://msdn.microsoft.com/en-us/library/ie/cc197016(v=vs.85).aspx
            return (window.localStorage.remainingSpace/1024/1024).round(4);
        }
        else{
            var mb = 0;
            for(var x in localStorage){
                //Uncomment out console.log to see *all* items in local storage
                //console.log(x+"="+((localStorage[x].length * 2)/1024/1024).toFixed(4)+" MB");
                mb += localStorage[x].length
            }
            //return Math.round(((mb * 2)/1024/1024) * 100)/100;
            return ((mb *2)/1024/1024).round(4);
        }
    }

    /**
     * A Global prototype that provides rounding capabilities.
     * TODO reevaluate if this should be local in scope or global.
     * @param places
     * @returns {number}
     */
    Number.prototype.round = function(places){
        places = Math.pow(10, places);
        return Math.round(this * places)/places;
    }

    /**
     * Call this to find out if app is online or offline
     * @returns {boolean}
     */
    this.getInternet = function(){
        if(Offline.state === 'up') {
            return true
        }
        else{
            return false;
        }
    }

    this.getGraphicsLayerById = function(/* String */ id){
        for(var layer in this.layers)
        {
            if(id == this.layers[layer].layerId){
                return this.layers[layer];
                break;
            }
        }
    }

    //////////////////////////
    ///
    /// PRIVATE methods
    ///
    //////////////////////////

    /**
     * Internal method for routing an edit requests. Offline edits are managed by size to maintain
     * as much consistency as possible across all browsers.
     * IMPORTANT: Graphic must have an ObjectId. You will not know the objects unique
     * id until after it has been committed to the feature service.
     * @param internet
     * @param graphic
     * @param layer
     * @param enumValue
     * @param callback Returns true if offline condition detected otherwise returns false.
     * Format: {count, success, id}
     * @private
     */
    this._applyEdits = function(/* Boolean */ internet, /* Graphic */ graphic,/* FeatureLayer */ layer, /* String */ enumValue, callback){
        var grSize = this.utils.apprxGraphicSize(graphic);
        var mb = this.getlocalStorageUsed();
        console.log("getlocalStorageUsed = " + mb + " MBs");
        if(grSize + mb > this._localEnum().LOCAL_STORAGE_MAX_LIMIT /* MB */){
            alert("The graphic you are editing is too big (" + grSize.toFixed(4) + " MBs) for the remaining storage. Please try again.")
            callback(0,false,0);
            return;
        }
        else if(mb > this._localEnum().LOCAL_STORAGE_MAX_LIMIT /* MB */){
            alert("You are almost over the local storage limit. No more data can be added.")
            callback(0,false,0);
            return;
        }
        if(internet === false){
            this._addToLocalStore(graphic,layer,enumValue,callback);
            this._startOfflineListener();
        }
        else{
            //No need for a callback because this is an online request and it's immediately
            //pushed to Feature Service.
            this._layerEditManager(graphic,layer,enumValue,this.enum(),function(count,success,id,error){
                console.log("id: " + id + ", success: " + success);
            });
        }
    }

    /**
     * Directly implements the applyEdits() method for ADDS, UPDATES and DELETES.
     * NOTE: objectid's usually don't exist on new points, lines, polys that have not
     * been committed to the server yet.
     * @param graphic
     * @param layer
     * @param value
     * @param localEnum
     * @param mCallback
     * @private
     */
    this._layerEditManager = function(
        /* Graphic */ graphic,
        /* FeatureLayer */ layer,
        /* String */ value,
        /* Object */ localEnum,
        /* Object */ mCallback){
        switch(value){
            case localEnum.DELETE:
                layer.applyEdits(null,null,[graphic],function(addResult,updateResult,deleteResult){
                    if(mCallback != null && typeof deleteResult != "undefined" && deleteResult.length > 0) {
                        mCallback(count,deleteResult[0].success,deleteResult[0].objectId,null);
                        console.log("deleteResult ObjectId: " + deleteResult[0].objectId + ", Success: " + deleteResult[0].success);
                    }
                }.bind(this),
                    function(error){
                        console.log("_layer: " + error.lineNumber + " " + error.message);
                        mCallback(deleteResult[0].objectId,false,null,error);
                    }.bind(this)
                );
                break;
            case localEnum.ADD:
                layer.applyEdits([graphic],null,null,function(addResult,updateResult,deleteResult){
                    if(mCallback != null && typeof addResult != "undefined" && addResult.length > 0) {
                        mCallback(count,addResult[0].success,addResult[0].objectId,null);
                        console.log("addResult ObjectId: " + addResult[0].objectId + ", Success: " + addResult[0].success);
                    }
                }.bind(this),
                    function(error){
                        console.log("_layer: " + error.lineNumber + " " + error.message);
                        mCallback(addResult[0].objectId,false,null,error);
                    }.bind(this)
                );
                break;
            case localEnum.UPDATE:
                layer.applyEdits(null,[graphic],null,function(addResult,updateResult,deleteResult){
                    if(mCallback != null && typeof updateResult != "undefined" && updateResult.length > 0) {
                        mCallback(count,updateResult[0].success,updateResult[0].objectId,null);
                        console.log("updateResult ObjectId: " + updateResult[0].objectId + ", Success: " + updateResult[0].success);
                    }
                }.bind(this),
                    function(error){
                        console.log("_layer: " + error.toString);
                        mCallback(updateResult[0].objectId,false,null,error)
                    }.bind(this)
                );
                break;
        }
    }

    /**
     * Initiates adding a graphic to temp local storage.
     * Dispatches a pendingEditEvent whereby message = pendingEventObject.
     * @param graphic
     * @param layer
     * @param enumValue
     * @param callback
     * @private
     */
    this._addToLocalStore = function(/* Graphic */ graphic, /* FeatureLayer */ layer, /* String */ enumValue,callback){
        var arr = this._getTempLocalStore();
        var serializedGraphic = this._serializeGraphic(graphic,layer,enumValue);
        var setItem = new this._duplicateLocalStorageValue();
        //If localStorage does NOT exist
        if(arr === null){
            var setAttempt = this._setTempLocalStore(serializedGraphic);
            if(setAttempt == true){
                setItem.success = true;
                setItem.duplicate = false;
            }
            else{
                setItem.success = false;
                setItem.duplicate = false;
            }
            callback(0,setItem,0);
        }
        else{
            setItem = this._updateExistingLocalStore(serializedGraphic);
            callback(0,setItem,0);
        }
        layer.add(graphic);
        // this._dispatchEvent(true,this._localEnum().PENDING_EDIT_EVENT);
    }

    this._startOfflineListener = function(){
        if(this._reestablishedInternetListener == null){
            function onlineStatusHandler(evt){
                if(evt.detail.message == true && evt.detail.type == this._localEnum().INTERNET_STATUS_EVENT){
                    console.log("_startOfflineListener - internet reestablished");
                    var arr = null;
                    try{var arr = this._getTempLocalStore()}catch(err){console.log("onlineStatusHandler: " + err.toString())};
                    if(arr != null){
                        this._reestablishedInternet();
                    }
                }
            }
            document.addEventListener("offlineEditEvent",onlineStatusHandler.bind(this),false);
            this._reestablishedInternetListener = 1;
            console.log("starting offline listener.");
        }
    }

    /**
     * Custom Event dispatcher. Always listen for offlineEditEvent and break down different
     * events via the event.detail.type string.
     * @param msg
     * @param event
     * @private
     */
    this._dispatchEvent = function(msg,event){
        //this.preventDefault();
        if (typeof msg != "defined" && window.CustomEvent) {
            var event = new CustomEvent("offlineEditEvent", {
                detail: {
                    type: event,
                    message: msg,
                    time: new Date()
                },
                bubbles: true,
                cancelable: true
            });
            document.dispatchEvent(event);
        }
    }

    /**
     * Creates a graphics array from localstorage and pushes all applicable edits to a
     * manager that handles the applyEdits() method.
     * @param callback (boolean,enum,graphicsLayerId,objectId) or (false,null,null,null)
     * if this.getStore() returns null
     * @private
     */
    this._reestablishedInternet = function(){

        var data = localStorage.getItem(this._localEnum().STORAGE_KEY);
        if(data != null){
            var split = data.split(this._localEnum().TOKEN);
            for(var property in split){
                var item = split[property];
                if(typeof item !== "undefined" && item.length > 0 && item !== null && item != ""){
                    var graphic = this._deserializeGraphic(item);
                    var layer = this.getGraphicsLayerById(graphic.layer);
                    var valueToDelete = item;
                    this._layerEditManager(graphic.graphic,layer,graphic.enumValue,this.enum(),function(/* Number */ num, /* boolean */ success, /* String */ id,error){
                        var date = new Date();
                        var indexObject = new this._indexObject(graphic.layer,id,graphic.enumValue,success,graphic.graphic.geometry.type,date) ;
                        var deleteTempItem = this._deleteItemTempLocalStore(valueToDelete);
                        this._setItemLocalStoreIndexObject(indexObject);
                    }.bind(this));
                }
            }
        }
        else{
            console.log("_reestablishedInternet: localStorage was empty.");
        }
    }

    /**
     * Delete all items stored by this library using its unique key.
     * Does NOT delete anything else from localStorage.
     */
    this._deleteTempLocalStore = function(){
        console.log("deleting localStore");
        try{
            localStorage.removeItem(this._localEnum().STORAGE_KEY);
        }
        catch(err){
            return err.stack;
        }
        return true;
    }

    /**
     * Returns the raw local storage object.
     * @returns {*}
     * @private
     */
    this._getTempLocalStore = function(){
        return localStorage.getItem(this._localEnum().STORAGE_KEY);
    }

    /**
     * Takes a serialized geometry and adds it to localStorage
     * @param serializedGraphic
     * @return
     * @private
     */
    this._updateExistingLocalStore = function(/* String */ serializedGraphic){
        var duplicateObj = new this._duplicateLocalStorageValue();
        var localStore = this._getTempLocalStore();
        var split = localStore.split(this._localEnum().TOKEN);
        var dupeFlag = false;
        for(var property in split){
            var item = split[property];
            if(typeof item !== "undefined" && item.length > 0 && item !== null){
                var sub = serializedGraphic.substring(0,serializedGraphic.length - 3);
                //This is not the sturdiest way to verify if two geometries are equal
                if(sub === item){
                    console.log("updateExistingLocalStore: duplicate item skipped.");
                    this._dispatchEvent(true,"duplicateEditEvent");
                    dupeFlag = true;
                    break;
                }
            }
        }
        if(dupeFlag == false) {
            var setValue = this._setTempLocalStore(localStore + serializedGraphic);
            if(setValue == true){
                duplicateObj.success = true;
                duplicateObj.duplicate = false;
            }
            else{
                duplicateObj.success = false;
                duplicateObj.duplicate = false;
            }
        }
        else{
            duplicateObj.duplicate = true;
        }
        return duplicateObj;
    }

    /**
     * Sets the localStorage. NOTE: This is a temporary location to store pending edits.
     * The graphic may not have a UID if it has not been processed by the feature service.
     * This poses a minor storage issue. So, in this version of the library we simply
     * store the serialized graphic information and append it to any other pending edits.
     * @param serializedGraphic
     * @returns {_duplicateLocalStorageValue} returns true if success, else false. Writes
     * error stack to console.
     */
    this._setTempLocalStore = function(/* String */ serializedGraphic){
        var success = false;
        try{
            localStorage.setItem(this._localEnum().STORAGE_KEY,serializedGraphic);
            success = true;
        }
        catch(err){
            console.log("_setTempLocalStore(): " + err.toString);
            success = false;
        }
        return success;
    }

    /**
     * Deletes an item in temporary local store.
     * REQUIRES: ObjectId field is present
     * @param objectId
     * @param callback
     * @private
     */
    this._deleteObjectIdTempLocalStore = function(/* String */ objectId,callback){
        var success = false;
        var localStore = localStorage.getItem(this._localEnum().STORAGE_KEY);
        if(localStore != null){
            var splitStore = localStore.split(this._localEnum().TOKEN);
            for(var property in splitStore){
                var test = splitStore[property];
                if(typeof test !== "undefined" && test.length > 0 && test != null && Boolean(test) != false){
                    var item = JSON.parse(splitStore[property]);
                    var q = JSON.parse(item.attributes);
                    if(q.hasOwnProperty("objectid") && q.objectid == objectId){
                        splitStore.splice(parseFloat(property),1);
                        var newArr = this._reserializeGraphicsArray(splitStore);
                        localStorage.removeItem(this._localEnum().STORAGE_KEY);
                        var setItem = this._setTempLocalStore(newArr);
                        setItem == true ? success = true : success = false;
                        break;
                    }
                }
            }
        }
        callback(success);
    }

    /**
     * Deletes an item in temporary local store.
     * @param entry String representing an entire entry contained in the local store
     * @param callback
     * @private
     */
    this._deleteItemTempLocalStore = function(/* String */ entry,callback){
        var success = false;
        var localStore = localStorage.getItem(this._localEnum().STORAGE_KEY);
        if(localStore != null){
            var splitStore = localStore.split(this._localEnum().TOKEN);
            for(var property in splitStore){
                var test = splitStore[property];
                if(typeof test !== "undefined" && test.length > 0 && test != null && Boolean(test) != false){
//                    var graphic = this._deserializeGraphic(test);
                    if(test == entry){
                        splitStore.splice(parseFloat(property),1);
                        var newArr = this._reserializeGraphicsArray(splitStore);
                        localStorage.removeItem(this._localEnum().STORAGE_KEY);
                        var setItem = this._setTempLocalStore(newArr);
                        setItem == true ? success = true : success = false;
                        break;
                    }
                }
            }
        }
        return success;
    }

    /**
     * Validates if an item has been deleted.
     * @param objectId
     * @returns {boolean}
     * @private
     */
    this._isItemTempLocalStore = function(/* String */ objectId){
        var localStore = localStorage.getItem(this._localEnum().INDEX_KEY);
        if(localStore != null){
            var split = localStore.split(this._localEnum().TOKEN);
            for(var property in split){
                var item = JSON.parse(split[property]);
                if(typeof item !== "undefined" || item.length > 0 || item != null){
                    if(item.hasOwnProperty("id") && item.id == objectId){
                        return true;
                    }
                }
            }
        }
        return false;
    }

    /**
     * Takes an array of graphics as input and serializes them for local storage.
     * Use this when removing an item from the array. This allows you to
     * reconstitute the temporary local storage minus the item that was removed.
     * @param array
     * @returns {string}
     * @private
     */
    this._reserializeGraphicsArray = function( /* Array */ array){
        var newStr = "";
        var length = array.length;
        for(var i=0;i<length;i++){
            var segment = array[i];
            if(!!segment == false)continue; //skip null values or empty strings
            //var newSegment = segment.replace(/\\/g,'');

            try{
                //validate that the segment is parseable.
                //If not then something went wrong.
                var test = JSON.parse(segment);
                if(typeof test != "undefined"){
                    newStr += segment + this._localEnum().TOKEN;
                }
            }
            catch(err){
                console.log("_reserializeGraphicsArray: " + err.toString());
            }
        }
        return newStr;
    }

    this._deleteLocalStoreIndex = function(){
        console.log("deleting localStoreIndex");
        try{
            localStorage.removeItem(this._localEnum().INDEX_KEY);
        }
        catch(err){
            return err.stack;
        }
        return true;
    }

    /**
     * Validates if an item has been deleted.
     * @param objectId
     * @returns {boolean}
     * @private
     */
    this._isItemLocalStoreIndex = function(/* String */ objectId){
        var localStore = localStorage.getItem(this._localEnum().INDEX_KEY);
        if(localStore != null){
            var split = localStore.split(this._localEnum().TOKEN);
            for(var property in split){
                var item = JSON.parse(split[property]);
                if(typeof item !== "undefined" || item.length > 0 || item != null){
                    if(item.hasOwnProperty("id") && item.id == objectId){
                        return true;
                    }
                }
            }
        }
        return false;
    }

    /**
     * Retrieves an item from index
     * @param objectId
     * @returns {Object} returns null if item not found
     * @private
     */
    this._getItemLocalStoreIndex = function(/* String */ objectId){
        var localStore = localStorage.getItem(this._localEnum().INDEX_KEY);
        if(localStore != null){
            var split = localStore.split(this._localEnum().TOKEN);
            for(var property in split){
                var item = JSON.parse(split[property]);
                if(typeof item !== "undefined" || item.length > 0 || item != null){
                    if(item.hasOwnProperty("id") && item.id == objectId){
                        return item;
                    }
                }
            }
        }
        return null;
    }

    /**
     * Pushes data to the Index. Index uses localStorage for cross-platform consistency.
     * @param indexObject uses the model _indexObject
     * @returns {*}
     * @private
     */
    this._setItemLocalStoreIndexObject = function(/* Object */ indexObject){
        var mIndex = JSON.stringify(indexObject);
        var localStore = this.getLocalStoreIndex();
        try{
            if(localStore == null || typeof localStore == "undefined"){
                localStorage.setItem(this._localEnum().INDEX_KEY,mIndex + this._localEnum().TOKEN);
            }
            else{
                localStorage.setItem(this._localEnum().INDEX_KEY,localStore + mIndex + this._localEnum().TOKEN);
            }
            success = true;
            this._dispatchEvent(indexObject,this._localEnum().INDEX_UPDATE_EVENT);
        }
        catch(err){
            console.log("_setItemLocalStoreIndexObject(): " + err.stack);
            success = false;
        }
        return success;
    }

    /**
     * Returns a graphic that has been reconstituted from localStorage.
     * @param item
     * @returns {{graphic: esri.Graphic, layer: *, enumValue: *}}
     * @private
     */
    this._deserializeGraphic = function(/* Graphic */ item){
        var jsonItem = JSON.parse(item);
        var geometry = JSON.parse(jsonItem.geometry);
        var attributes = JSON.parse(jsonItem.attributes);
        var enumValue = jsonItem.enumValue;
        var layer = JSON.parse(jsonItem.layer);
        var finalGeom = null;
        switch(geometry.type){
            case "polyline":
                finalGeom = new esri.geometry.Polyline(new esri.SpatialReference(geometry.spatialReference.wkid));
                for(var path in geometry.paths){
                    finalGeom.addPath(geometry.paths[path]);
                }
                break
            case "point":
                finalGeom = new esri.geometry.Point(geometry.x,geometry.y,new esri.SpatialReference(geometry.spatialReference.wkid));
                break;
            case "polygon":
                finalGeom = new esri.geometry.Polygon(new esri.SpatialReference(geometry.spatialReference.wkid));
                for(var ring in geometry.rings){
                    finalGeom.addRing(geometry.rings[ring]);
                }
                break;
        }
        var graphic = new esri.Graphic(finalGeom, null, attributes, null);
        return {"graphic":graphic,"layer":layer,"enumValue":enumValue};
    }

    /**
     * Rebuilds Geometry in a way that can be serialized/deserialized
     * @param graphic
     * @param layer
     * @param enumValue
     * @returns {string}
     * @private
     */
    this._serializeGraphic = function(/* Graphic */ graphic, layer, enumValue){
        var json = new this._jsonGraphicsObject();
        json.layer = layer.layerId;
        json.enumValue = enumValue;
        json.geometry = JSON.stringify(graphic.geometry)
        if(graphic.hasOwnProperty("attributes")){
            if(graphic.attributes != null){
                try{
                    var q = this._hydrate.stringify(graphic.attributes);
                }
                catch(err){
                    console.log("_serializeGraphic: " + err.toString());
                }
                json.attributes = q;
            }
        }
        return JSON.stringify(json) + this._localEnum().TOKEN;
    }

    /**
     * Rebuilds Geometry in a way that can be serialized/deserialized
     * @param graphic
     * @param layer
     * @param enumValue
     * @returns {string}
     * @private
     */
    this._serializeGraphicNoToken = function(/* Graphic */ graphic, layer, enumValue){
        var json = new this._jsonGraphicsObject();
        json.layer = layer.layerId;
        json.enumValue = enumValue;
        json.geometry = JSON.stringify(graphic.geometry)
        if(graphic.hasOwnProperty("attributes")){
            if(graphic.attributes != null){
                try{
                    var q = this._hydrate.stringify(graphic.attributes);
                }
                catch(err){
                    console.log("_serializeGraphic: " + err.toString());
                }
                json.attributes = q;
            }
        }
        return JSON.stringify(json);
    }

    //////////////////////////
    ///
    /// INTERNAL Models
    ///
    //////////////////////////

    /**
     * Model for storing serialized graphics
     * @private
     */
    this._jsonGraphicsObject = function(){
        this.layer = null;
        this.enumValue = null;
        this.geometry = null;
        this.attributes = null;
        this.date = null;
    }

    /**
     * Model for holding temporary local store data that validates
     * if an item has been added successfully and whether or not it
     * was a duplicate.
     * @private
     */
    this._duplicateLocalStorageValue = function(){
        /**
         * Boolean: whether or not the item was successfully added to local storage
         */
        this.success = null;
        /**
         * Boolean: indicates if the item was a duplicate entry and therefore was not added to local storage
         */
        this.duplicate = null;
    }

    /**
     * Model for storing serialized index info.
     * @param layerId
     * @param id
     * @param enumType
     * @param success
     * @param geoType The type of Esri geometry
     * @param date Date
     * @private
     */
    this._indexObject = function(/* String */ layerId,
                                 /* String */ id, /* String */ enumType, /* boolean */ success,
                                 /* String */ geoType, /* Date */ date){
        this.id = id;
        this.layerId = layerId;
        this.type = enumType;
        this.success = success;
        this.geometryType = geoType;
        this.date = date;
    }

    /**
     * Model for storing results when attempting to apply edits
     * after internet has been reestablished
     * @param success
     * @param enumString
     * @param graphicsLayerId
     * @param objectId
     * @param error
     * @private
     */
    this._editResultObject = function(/* boolean */ success, /* String */ enumString,
                                      /* int */ graphicsLayerId, /* int */ objectId,/* String */ date, error){
        this.success = success;
        this.enumString = enumString;
        this.graphicsLayerId = graphicsLayerId;
        this.objectId = objectId;
        this.date = date;
        this.error = error;
    }

    //////////////////////////
    ///
    /// INITIALISE
    ///
    //////////////////////////

    /**
     * Auto-detects online/offline conditions.
     * Listen for INTERNET_STATUS_EVENT = true/false.
     * Dependant on Offline.js
     * @private
     */
    this._offlineMonitor = function(){
        Offline.options = { checkOnLoad: true, reconnect: true, requests: false };
        Offline.check();
        Offline.on('up down', function(){
            if(Offline.state === 'up'){
                console.log("internet is up.");
                this._dispatchEvent(true,this._localEnum().INTERNET_STATUS_EVENT);
            }
            else{
                console.log("internet is down.");
                this._dispatchEvent(false,this._localEnum().INTERNET_STATUS_EVENT);
            }
        }.bind(this));
    }

    /**
     * Load src
     * TO-DO: Needs to be made AMD compliant!
     * @param urlArray
     * @param callback
     * @private
     */
    this._loadScripts = function(/* Array */ urlArray, callback)
    {
        var thisScriptUrl = getScriptURL();
        var parse_url = /^(?:([A-Za-z]+):)?(\/{0,3})([0-9.\-A-Za-z]+)(?::(\d+))?(?:\/([^?#]*))?(?:\?([^#]*))?(?:#(.*))?$/;
        var parts = parse_url.exec( thisScriptUrl );
        var baseUrl = '/' + parts[5].substring(0,parts[5].lastIndexOf("/"));
        count = 0;
        for(var i in urlArray){
            try{
                var head = document.getElementsByTagName('head')[0];
                var script = document.createElement('script');
                script.type = 'text/javascript';
                script.src = baseUrl + '/' + urlArray[i];
                script.onreadystatechange = function(){
                    count++;
                    console.log("Script loaded. " + this.src);
                    if(count == urlArray.length) callback();
                };
                script.onload = function(){
                    count++;
                    console.log("Script loaded. " + this.src);
                    if(count == urlArray.length) callback();
                };
                head.appendChild(script);
            }
            catch(err){
                console.log("_loadScripts: " + err.stack);
            }
        }
    }

    this._parseFeatureLayers = function(/* Event */ map){
        var layerIds = map.graphicsLayerIds;
        try{
            for (var i in layerIds){
                var layer = map.getLayer(layerIds[i]);
                if(layer.hasOwnProperty("type") && layer.type.toLowerCase() == "feature layer"){
                    if(layer.isEditable() == true){
                        this.layers.push(layer);
                    }
                }
                else{
                    throw ("Layer not editable: " + layer.url );
                }
            }
        }
        catch(err){
            console.log("_parseFeatureLayer: " + err.stack);
        }
    }

    /**
     * Initializes the OfflineStore library. Loads required src.
     * @see Required script sare set in _localEnum.
     * @type {*}
     * @private
     */
    this._init = function(){
        this._loadScripts(this._localEnum().REQUIRED_LIBS,function(){
            this.utils = new OfflineUtils();
            this._parseFeatureLayers(this.map);
            this._hydrate = new Hydrate();
            if(typeof Offline == "object"){
                this._offlineMonitor();
                console.log("OfflineStore is ready.")
                var arr = this._getTempLocalStore();
                if(arr != null && Offline.state === 'up'){
                    this._reestablishedInternet();
                }
                else if(arr != null && Offline.state !== 'up'){
                    this._startOfflineListener();
                }
            }
        }.bind(this));
    }.bind(this)()

    /**
     * Allow application builders to detect potential fatal events that
     * could affect data integrity.
     * TO-DO some errors like those in callbacks may not be trapped by this!
     * @param msg
     * @param url
     * @param line
     * @returns {boolean}
     */
    window.onerror = function (msg,url,line){
        console.log(msg + ", " + url + ":" + line);
        if (window.CustomEvent) {
            var event = new CustomEvent("windowErrorEvent", {
                detail: {
                    message: msg,
                    time: new Date()
                },
                bubbles: true,
                cancelable: true
            });
            document.dispatchEvent(event);
        }
        return true;
    }
};