"use strict";

define([
    "edit/editsStore",
    "edit/attachmentsStore",

    "dojo/Evented",
    "dojo/_base/Deferred",
    "dojo/promise/all",
    "dojo/_base/declare",
    "dojo/_base/lang",
    "dojo/_base/array",
	"dojo/dom-attr",
	"dojo/dom-style",

    "esri/layers/GraphicsLayer",
    "esri/graphic",
    "esri/symbols/SimpleMarkerSymbol",
    "esri/symbols/SimpleLineSymbol",
    "esri/symbols/SimpleFillSymbol",

    "esri/request"],
	function(editsStore, AttachmentsStore,
		Evented,Deferred,all,declare,lang,array,domAttr,domStyle,
		GraphicsLayer,Graphic,SimpleMarkerSymbol,SimpleLineSymbol,SimpleFillSymbol,
        esriRequest)
{
    return declare([Evented],
    {
        _onlineStatus: "online",
        _featureLayers: {},

        ONLINE: "online",				// all edits will directly go to the server
        OFFLINE: "offline", 			// edits will be enqueued
        RECONNECTING: "reconnecting", 	// sending stored edits to the server

        // manager emits event when...
        events: {
            EDITS_SENT: 'edits-sent', 			// ...whenever any edit is actually sent to the server
            EDITS_ENQUEUED: 'edits-enqueued', 	// ...when an edit is enqueued (and not sent to the server)
            ALL_EDITS_SENT: 'all-edits-sent', 	// ...after going online and there are no pending edits in the queue
            ATTACHMENT_ENQUEUED: 'attachment-enqueued',
            ATTACHMENTS_SENT: 'attachments-sent'
        },

        _checkFileAPIs: function()
        {
            if( window.File && window.FileReader && window.FileList && window.Blob )
            {
                console.log("All APIs supported!");

                if(!XMLHttpRequest.prototype.sendAsBinary )
                {               
                    // https://code.google.com/p/chromium/issues/detail?id=35705#c40
                    XMLHttpRequest.prototype.sendAsBinary = function(datastr) 
                    {
                        function byteValue(x) {
                            return x.charCodeAt(0) & 0xff;
                        }
                        var ords = Array.prototype.map.call(datastr, byteValue);
                        var ui8a = new Uint8Array(ords);
                        this.send(ui8a.buffer);
                    }
                    console.log("extending XMLHttpRequest");
                }
                return true;
            }
            else
            {
                alert('The File APIs are not fully supported in this browser.');
                return false;
            }
        },

        /**
         * Overrides a feature layer.
         * @param layer
         * @returns deferred
         */
        extend: function(layer, callback)
        {
            var self = this;

            // we keep track of the FeatureLayer object
            this._featureLayers[ layer.url ] = layer;

            // replace the applyEdits() method
            layer._applyEdits = layer.applyEdits;


            // attachments 
            layer._addAttachment = layer.addAttachment;
            layer._queryAttachmentInfos = layer.queryAttachmentInfos;
            layer._deleteAttachments = layer.deleteAttachments;

            if( !this._checkFileAPIs())
            {
                return callback(false, "File APIs not supported");
            }

            try
            {
                layer.attachmentsStore = new AttachmentsStore();

                if( /*false &&*/ layer.attachmentsStore.isSupported() )
                    layer.attachmentsStore.init(callback);
                else
                    return callback(false, "indexedDB not supported");
            }
            catch(err)
            {
                console.log("problem!  " + err.toString())
            }

            /*

            operations supported offline:
            1. add a new attachment to an existing feature
            2. add a new attachment to a new feature
            3. remove an attachment that is already in the server... how do we know about it?
            4. remove an attachment that is not in the server yet
            5. update an existing attachment to an existing feature, how do we know about it?
            6. update a new attachment

            concerns:
            - should the key in the db be the objectId or the attachmentId?
            - manage the relationship between offline features and attachments: what if the user wants to add
              an attachment to a feature that is still offline? we need to keep track of objectids so that when
              the feature is sent to the server and receives a final objectid we replace the temporary negative id
              by its final objectid
            - what if the user deletes an offline feature that had offline attachments? we need to discard the attachment              

            */            

            //
            // attachments
            //
            layer.queryAttachmentInfos = function(objectId,callback,errback){
                if( self.getOnlineStatus() == self.ONLINE)
                {
                    var def = this._queryAttachmentInfos(objectId,
                        function()
                        {
                            console.log(arguments);
                            self.emit(self.events.ATTACHMENTS_INFO,arguments);
                            callback && callback.apply(this,arguments);
                        },
                        errback);
                    return def;
                }
                else
                {
                    // NEEDS TESTING
                    var deferred = new Deferred();
                    this.attachmentsStore.getAttachmentsByFeatureId(objectId, function(found,attachments)
                    {
                        callback && callback.apply(this,attachments);
                        deferred.resolve(attachments);
                    });
                    return deferred;
                }
            }

            layer.addAttachment = function(objectId,formNode,callback,errback){
                if( self.getOnlineStatus() == self.ONLINE)
                {
                    return this._addAttachment(objectId,formNode,
                        function(){
                            self.emit(self.events.ATTACHMENTS_SENT,arguments);
                            callback && callback.apply(this,arguments);
                        },
                        function(err){
                            console.log("addAttachment: " + err)
                            errback && errback.apply(this,arguments);
                        }
                    )
                }
                else
                {
                    // TODO: we need to:
                    // 1. extract the file from formNode
                    // 2. store the file in a format that can be later sent to the server using REST API
                    // concerns: 
                    // a) the mechanism to convert a file path into binary data to be sent over POST
                    // is normally handled by the API/Browser... how can we reuse as much of that mechanism as 
                    // possible? There is a big leap between parameters we receive here (objectId and formNode) and
                    // the data that gets sent via REST to the server (use chrome devtools network tab to see that)
                    // b) what fields should be in our attachment object stored in the db?
                    // c) what should be the key in the db? objectid? attachmentid? problem is that when we are offline
                    // we don't know about attachmentids and other attachments that can be attached to the same feature
                    // we could use negative attachmentids, as we do with feature objectids
                    console.assert(objectId);

                    console.log(formNode);

                    // get input node(s)
                    // read file from input into variable
                    this._readFilesFromForm(formNode, function(files)
                    {
                        // callback called once for each input[type=file] node in formNode
                        console.log(files);
                        // store the file(s)
                    });

                }
            }

            // callback called once for each input[type=file] node in formNode
            layer._readFilesFromForm = function(formNode, callback)
            {
                var inputNodes = array.filter(formNode.elements, function(node) { return node.type == "file"});
                inputNodes.forEach(function(inputNode)
                {
                    var files = [];
                    var pendingFiles = inputNode.files.length
                    var i, n = inputNode.files.length;

                    if( pendingFiles == 0)
                        return callback(files);

                    for(i=0;i<n; i++)
                    {
                        var file = inputNode.files[i];

                        console.log("reading file", file.name);

                        var reader = new FileReader();

                        // closure to keep 'file' value
                        reader.onload = (function(theFile){
                            return function(evt) {
                                console.log(evt);
                                files.push({
                                    name: theFile.name,
                                    type: theFile.type,
                                    content: evt.target.result,
                                    size: theFile.size
                                });
                                pendingFiles--;
                                if( pendingFiles == 0)
                                    return callback(files);
                            }
                        }(file));

                        reader.readAsBinaryString(file);
                    };
                });
                
            }

            layer.deleteAttachments = function(objectId,attachmentsIds,callback,errback){
                if( self.getOnlineStatus() == self.ONLINE)
                {
                    var def = this._deleteAttachments(objectId,attachmentsIds,
                        function()
                        {
                            self.emit(self.events.ATTACHMENTS_DELETED,arguments);
                            callback && callback.apply(this,arguments);
                        },
                        function(err){
                            console.log("deleteAttachments: " + err)
                            errback && errback.apply(this,arguments);
                        });
                    return def;
                }
                else
                {
                	console.log("deleteAttachments() - OFFLINE", objectId, attachmentsIds);

                    
                }
            }


            //
            // other functions
            //

            /**
             * Overrides the ArcGIS API for JavaSccript applyEdits() method.
             * @param adds Creates a new edit entry.
             * @param updates Updates an existing entry.
             * @param deletes Deletes an existing entry.
             * @param callback Called when the operation is complete.
             * @param errback  An error object is returned if an error occurs
             * @returns {*} deferred
             */
            layer.applyEdits = function(adds,updates,deletes,callback,errback)
            {
                // inside this method, 'this' will be the FeatureLayer
                // and 'self' will be the offlineFeatureLayer object

                if( self.getOnlineStatus() == self.ONLINE)
                {
                    var def = this._applyEdits(adds,updates,deletes,
                        function()
                        {
                            self.emit(self.events.EDITS_SENT,arguments);
                            callback && callback.apply(this,arguments);
                        },
                        errback);
                    return def;
                }
                else
                {
                    var deferred = new Deferred();
                    var results = {	addResults:[],updateResults:[], deleteResults:[] };
                    var updatesMap = {};

                    this.onBeforeApplyEdits(adds, updates, deletes);

                    adds = adds || [];
                    adds.forEach(function(addEdit)
                    {
                        var objectId = this.getNextTempId();
                        addEdit.attributes[ this.objectIdField ] = objectId;
                        var result = editsStore.pushEdit(editsStore.ADD, this.url, addEdit);
                        results.addResults.push({ success:result.success, error: result.error, objectId: objectId});
                        if(result.success)
                        {
                            var phantomAdd = new Graphic(
                                addEdit.geometry,
                                self._getPhantomSymbol(addEdit.geometry, editsStore.ADD),
                                {
                                    objectId: objectId
                                });
                            this._phantomLayer.add(phantomAdd);
							domAttr.set(phantomAdd.getNode(),"stroke-dasharray","10,4");
							domStyle.set(phantomAdd.getNode(), "pointer-events","none");
                        }
                    },this);

                    updates = updates || [];
                    updates.forEach(function(updateEdit)
                    {
                        var objectId = updateEdit.attributes[ this.objectIdField ];
                        var result = editsStore.pushEdit(editsStore.UPDATE, this.url, updateEdit);
                        results.updateResults.push({success:result.success, error: result.error, objectId: objectId});
                        updatesMap[ objectId ] = updateEdit;
                        if(result.success)
                        {
                            var phantomUpdate = new Graphic(
                                updateEdit.geometry,
                                self._getPhantomSymbol(updateEdit.geometry, editsStore.UPDATE),
                                {
                                    objectId: objectId
                                });
                            this._phantomLayer.add(phantomUpdate);
							domAttr.set(phantomUpdate.getNode(),"stroke-dasharray","5,2");
							domStyle.set(phantomUpdate.getNode(), "pointer-events","none");
                        }
                    },this);

                    deletes = deletes || [];
                    deletes.forEach(function(deleteEdit)
                    {
                        var objectId = deleteEdit.attributes[ this.objectIdField ];
                        var result = editsStore.pushEdit(editsStore.DELETE, this.url, deleteEdit);
                        results.deleteResults.push({success:result.success, error: result.error, objectId: objectId});
                        if(result.success)
                        {
                            var phantomDelete = new Graphic(
                                deleteEdit.geometry,
                                self._getPhantomSymbol(deleteEdit.geometry, editsStore.DELETE),
                                {
                                    objectId: objectId
                                });
                            this._phantomLayer.add(phantomDelete);
							domAttr.set(phantomDelete.getNode(),"stroke-dasharray","4,4");
							domStyle.set(phantomDelete.getNode(), "pointer-events","none");
                        }
                    },this);

                    /* we already pushed the edits into the local store, now we let the FeatureLayer to do the local updating of the layer graphics */
                    setTimeout(function()
                    {
                        this._editHandler(results, adds, updatesMap, callback, errback, deferred);
                        self.emit(self.events.EDITS_ENQUEUED, results);
                    }.bind(this),0);
                    return deferred;
                }
            }; // layer.applyEdits()

            // we need to identify ADDs before sending them to the server
            // we assign temporary ids (using negative numbers to distinguish them from real ids)
            layer._nextTempId = -1;
            layer.getNextTempId = function()
            {
                return this._nextTempId--;
            };

            function _initPhantomLayer()
            {
				try
				{
                    layer._phantomLayer = new GraphicsLayer({opacity:0.8});
					layer._map.addLayer(layer._phantomLayer);
                }
				catch(err)
				{
                    console.log("Unable to init PhantomLayer");
                }
            }
            _initPhantomLayer();

        }, // extend

        _phantomSymbols: [],

        _getPhantomSymbol: function(geometry, operation)
        {
            if( this._phantomSymbols.length == 0)
            {
                var color = [0,255,0,255];
				var width = 1.5;

                this._phantomSymbols['point'] = [];
                this._phantomSymbols['point'][editsStore.ADD] = new SimpleMarkerSymbol({
                    "type": "esriSMS", "style": "esriSMSCross",
                    "xoffset": 10, "yoffset": 10,
                    "color": [255,255,255,0], "size": 15,
                    "outline": { "color": color, "width": width, "type": "esriSLS", "style": "esriSLSSolid" }
                });
                this._phantomSymbols['point'][editsStore.UPDATE] = new SimpleMarkerSymbol({
                    "type": "esriSMS", "style": "esriSMSCircle",
                    "xoffset": 0, "yoffset": 0,
                    "color": [255,255,255,0], "size": 15,
                    "outline": { "color": color, "width": width, "type": "esriSLS", "style": "esriSLSSolid" }
                });
                this._phantomSymbols['point'][editsStore.DELETE] = new SimpleMarkerSymbol({
                    "type": "esriSMS", "style": "esriSMSX",
                    "xoffset": 0, "yoffset": 0,
                    "color": [255,255,255,0], "size": 15,
                    "outline": { "color": color, "width": width, "type": "esriSLS", "style": "esriSLSSolid" }
                });
                this._phantomSymbols['multipoint'] = null;

                this._phantomSymbols['polyline'] = [];
                this._phantomSymbols['polyline'][editsStore.ADD] = new SimpleLineSymbol({
                    "type": "esriSLS", "style": "esriSLSSolid",
                    "color": color,"width": width
                });
                this._phantomSymbols['polyline'][editsStore.UPDATE] = new SimpleLineSymbol({
					"type": "esriSLS", "style": "esriSLSSolid", 
                    "color": color,"width": width
                });
                this._phantomSymbols['polyline'][editsStore.DELETE] = new SimpleLineSymbol({
					"type": "esriSLS", "style": "esriSLSSolid", 
                    "color": color,"width": width
                });

                this._phantomSymbols['polygon'] = [];
                this._phantomSymbols['polygon'][editsStore.ADD] = new SimpleFillSymbol({
                    "type": "esriSFS",
                    "style": "esriSFSSolid",
                    "color": [255,255,255,0],
                    "outline": { "type": "esriSLS", "style": "esriSLSSolid", "color": color, "width": width }
                });
                this._phantomSymbols['polygon'][editsStore.UPDATE] = new SimpleFillSymbol({
                    "type": "esriSFS",
                    "style": "esriSFSSolid",
                    "color": [255,255,255,0],
                    "outline": { "type": "esriSLS", "style": "esriSLSDash", "color": color, "width": width }
                });
                this._phantomSymbols['polygon'][editsStore.DELETE] = new SimpleFillSymbol({
                    "type": "esriSFS",
                    "style": "esriSFSSolid",
                    "color": [255,255,255,0],
                    "outline": { "type": "esriSLS", "style": "esriSLSDot", "color": color, "width": width }
                });
            }

            return this._phantomSymbols[ geometry.type ][ operation ];
        },

        /**
         * Forces library into an offline state. Any edits applied during this condition will be stored locally
         */
        goOffline: function()
        {
            console.log('going offline');
            this._onlineStatus = this.OFFLINE;
        },

        /**
         * Forces library to return to an online state. If there are pending edits,
         * an attempt will be made to sync them with the remote feature server
         * @param callback callback( boolean, errors )
         */
        goOnline: function(callback)
        {
            console.log('going online');
            this._onlineStatus = this.RECONNECTING;
            this._replayStoredEdits(function()
            {
                this._onlineStatus = this.ONLINE;
                callback && callback.apply(this,arguments);
            }.bind(this));
            //this.refresh();
        },

        /**
         * Determines if offline or online condition exists
         * @returns {string} ONLINE or OFFLINE
         */
        getOnlineStatus: function()
        {
            return this._onlineStatus;
        },

        /**
         * A string value representing human readable information on pending edits
         * @param edit
         * @returns {string}
         */
        getReadableEdit: function(edit)
        {
            var layer = this._featureLayers[ edit.layer ];
            var graphic = editsStore._deserialize(edit.graphic);
            var readableGraphic = graphic.geometry.type;
            var layerId = edit.layer.substring(edit.layer.lastIndexOf('/')+1);
            if(layer)
                readableGraphic += " [id=" + graphic.attributes[layer.objectIdField] + "]";
            return "o:" + edit.operation + ", l:" + layerId + ", g:" + readableGraphic;
        },

        /* internal methods */

        _optimizeEditsQueue: function()
        {
            // console.log("edits:", editsStore._retrieveEditsQueue().map(function(e){return this.getReadableEdit(e)},this));
            var optimizedEdits = {};
            var editCount = editsStore.pendingEditsCount();
            var optimizedCount = 0;

            while( editsStore.hasPendingEdits() )
            {
                var edit = editsStore.popFirstEdit();
                var layer = this._featureLayers[ edit.layer ];

                if( ! (edit.layer in optimizedEdits) )
                    optimizedEdits[edit.layer] = {}

                var layerEdits = optimizedEdits[edit.layer];
                var objectId = edit.graphic.attributes[ layer.objectIdField ];

                if( !( objectId in layerEdits) )
                {
                    // first edit we see of this feature, no optimization to apply
                    layerEdits[ objectId ] = edit;
                    optimizedCount += 1;
                }
                else
                {
                    // we already have seen one edit for this same feature... we can merge the two edits in a single operation
                    switch( edit.operation )
                    {
                        case editsStore.ADD:
                            /* impossible!! */
                            throw("can't add the same feature twice!");
                            break;
                        case editsStore.UPDATE:
                            layerEdits[ objectId ].graphic = edit.graphic;
                            break;
                        case editsStore.DELETE:
                            if(objectId < 0)
                            {
                                delete layerEdits[ objectId ];
                                optimizedCount -= 1;
                            }
                            else
                                layerEdits[objectId].operation = editsStore.DELETE;
                            break;
                    }
                }
                if( Object.keys(layerEdits).length == 0 )
                {
                    delete optimizedEdits[edit.layer]
                }
            }

            // console.log("optimized:",optimizedEdits);
            console.log("optimized", editCount, "edits into", optimizedCount,"edits of", Object.keys(optimizedEdits).length ,"layers");
            return optimizedEdits;
        },

        _replayStoredEdits: function(callback)
        {
            if( editsStore.hasPendingEdits() )
            {
                //
                // flatten the queue into unique edits for each feature, grouped by FeatureLayer
                //
                var optimizedEdits = this._optimizeEditsQueue();
                var promises = {};

                if( Object.keys(optimizedEdits).length == 0 )
                {
                    this.emit(this.events.ALL_EDITS_SENT);
                    callback && callback(true, {});
                    return;
                }

                //
                // send edits for each of the layers
                //
                for(var layerUrl in optimizedEdits)
                {
                    if(!optimizedEdits.hasOwnProperty(layerUrl))
                        continue;

                    var layer = this._featureLayers[ layerUrl ];
                    var layerEdits = optimizedEdits[layerUrl];

                    console.assert(Object.keys(layerEdits).length != 0)

                    layer.__onEditsComplete = layer["onEditsComplete"];
                    layer["onEditsComplete"] = function() { console.log("intercepting events onEditsComplete");}
                    layer.__onBeforeApplyEdits = layer["onBeforeApplyEdits"];
                    layer["onBeforeApplyEdits"] = function() { console.log("intercepting events onBeforeApplyEdits");}

                    var adds = [], updates = [], deletes = [];
                    for(var objectId in layerEdits)
                    {
                        if(!layerEdits.hasOwnProperty(objectId))
                            continue;

                        var edit = layerEdits[objectId];
                        switch(edit.operation)
                        {
                            case editsStore.ADD:
                                for(var i=0; i<layer.graphics.length; i++)
                                {
                                    var g = layer.graphics[i];
                                    if( g.attributes[layer.objectIdField] == edit.graphic.attributes[layer.objectIdField] )
                                    {
                                        layer.remove(g);
                                        break;
                                    }
                                };
                                delete edit.graphic.attributes[ layer.objectIdField ];
                                adds.push(edit.graphic);
                                break;
                            case editsStore.UPDATE:
                                updates.push(edit.graphic);
                                break;
                            case editsStore.DELETE:
                                deletes.push(edit.graphic)
                                break;
                        }
                    }

                    promises[layerUrl] = function(layer)
                    {
                        // unfortunately we can't use the promise that is returned from layer._applyEdits()
                        // because it returns 3 result parameters (addResults,updateResults,deleteResults)
                        // and when we combine all promises in the dojo/promise/all() method below this only
                        // supports promises that return one value
                        var dfd = new Deferred();
                        layer._applyEdits(adds,updates,deletes,
                            function(addResults,updateResults,deleteResults)
                            {
                                layer._phantomLayer.clear();
                                layer["onEditsComplete"] = layer.__onEditsComplete; delete layer.__onEditsComplete;
                                layer["onBeforeApplyEdits"] = layer.__onBeforeApplyEdits; delete layer.__onBeforeApplyEdits;
                                dfd.resolve({addResults:addResults,updateResults:updateResults,deleteResults:deleteResults}); // wrap three arguments in a single object
                            },
                            function(error)
                            {
                                layer["onEditsComplete"] = layer.__onEditsComplete; delete layer.__onEditsComplete;
                                layer["onBeforeApplyEdits"] = layer.__onBeforeApplyEdits; delete layer.__onBeforeApplyEdits;
                                dfd.reject(error);
                            }
                        );
                        return dfd;
                    }(layer);
                }

                //
                // wait for all requests to finish
                //
                var allPromises = new all(promises);
                allPromises.then(
                    function(responses)
                    {
                        console.log("all responses are back");
                        this.emit(this.events.EDITS_SENT);
                        this.emit(this.events.ALL_EDITS_SENT);
                        callback && callback(true,responses);
                    }.bind(this),
                    function(errors)
                    {
                        console.log("ERROR!!");
                        console.log(errors);
                        callback && callback(false,errors);
                    }.bind(this));
            } // hasPendingEdits()
            else
            {
                this.emit(this.events.ALL_EDITS_SENT);
                callback && callback(true, {});
            }
        },

    }); // declare
}); // define