/*
  Goal having something like:
 
	wsrpc.Connect("/ws");
	wsrpc.Connect("ws://127.0.0.1/ws");


	obj = {
		method1:function() {
			//Hello
		}
	}
	wsrpc.Export(obj);
 */

function WsRpc() {
	var ctx = this
	this._requests = {}
	this.connect = function(loc) {
			var ws = this.ws = new WebSocket(loc)
			ws.onopen = function() {
				ctx._requests = {}
				ctx.connected = true;
				if(ctx.onopen != undefined) {
					ctx.onopen(ctx)
				}
			}	
			ws.onmessage = function(evt) {
				//console.log("RCV:",evt.data)
				var obj = JSON.parse(evt.data)
				var arrObj = [].concat(obj); // if object add, if array concat
				for( var i = 0; i <arrObj.length; i++) {
					ctx.process(arrObj[i]);
				}
			}
			ws.onerror = function() { }
			ws.onclose = function() {
				if(ctx.connected == true) {
					ctx.connected = false;
					if(ctx.onclose != undefined) {
						ctx.onclose(ctx)
					}
				}
				
				// Retry
				setTimeout(function() {
					ctx.connect(loc)
				},3000) // 3 seconds reconnect
			}
		}
	this.process =  function(obj) {
		if (obj.op == "call") {
			if(obj.method == undefined || this._exports[obj.method] == undefined) {
				//TODO: Send objet to inform error
				return
			}
			function response(data) {
				var dataObj = {
					"op":"response",
					"reqId":obj.reqId,
					"data":data
				}
				ctx.ws.send(JSON.stringify(dataObj));
			}
			var nparams = [].concat(response,obj.param)
			this._exports[obj.method].apply(this._exports[obj.method],nparams)
		}
		if( obj.op == "response" ) {
			//console.log("Receiving response for:", obj.reqId)
			ctx._requests[obj.reqId](obj.data)
			delete ctx._requests[obj.reqId]
		}
	}
	this.call = function(method) {
		var aparam = Array.prototype.slice.call(arguments,1)
		return new Promise(function(resolve,reject) {
			if(ctx.connected == false ) {
				reject(Error("Not connected"))
			}

			var uuidStr = uuid();
			var callObj = {
				"reqId":uuidStr,
				"op":"call",
				"method":method,
				"param":aparam
			}
			ctx._requests[uuidStr] = resolve;
			//console.log("Sending a call:", method)
			ctx.ws.send(JSON.stringify(callObj));
		})
	}
	this.export = function(obj){
		this._exports = obj;
	}
			
	return this
}


function uuid() {
	var ret = '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);
	});
	return ret;
}