//app.js
var express = require('express');
var app = express();
var serv = require('http').Server(app);

app.get('/',function(req, res) {
	res.sendFile(__dirname + '/client/index.html');
});
app.use('/client',express.static(__dirname + '/client'));

serv.listen(2000);
console.log("Server started.");

var SOCKET_LIST = {};

var Entity = function(){
	var self = {
		x:250,
		y:250,
		spdX:0,
		spdY:0,
		id:"",
	}
	self.update = function(){
		self.updatePosition();
	}
	self.updatePosition = function(){
		self.x += self.spdX;
		self.y += self.spdY;
	}
	return self;
}

var Player = function(id){
	var self = Entity();
	self.id = id;
	self.number = "" + Math.floor(10 * Math.random());
	self.pressingRight = false;
	self.pressingLeft = false;
	self.pressingUp = false;
	self.pressingDown = false;
	self.maxSpd = 10;

	var super_update = self.update;
	self.update = function(){
		self.updateSpd();
		super_update();
	}


	self.updateSpd = function(){
		if(self.pressingRight)
			self.spdX = self.maxSpd;
		else if(self.pressingLeft)
			self.spdX = -self.maxSpd;
		else
			self.spdX = 0;

		if(self.pressingUp)
			self.spdY = -self.maxSpd;
		else if(self.pressingDown)
			self.spdY = self.maxSpd;
		else
			self.spdY = 0;
	}
	Player.list[id] = self;
	return self;
}
Player.list = {};
Player.onConnect = function(socket){
	var player = Player(socket.id);
	socket.on('keyPress',function(data){
		if(data.inputId === 'left')
			player.pressingLeft = data.state;
		else if(data.inputId === 'right')
			player.pressingRight = data.state;
		else if(data.inputId === 'up')
			player.pressingUp = data.state;
		else if(data.inputId === 'down')
			player.pressingDown = data.state;
	});
}
Player.onDisconnect = function(socket){
	delete Player.list[socket.id];
}
Player.update = function(){
	var pack = [];
	for(var i in Player.list){
		var player = Player.list[i];
		player.update();
		pack.push({
			x:player.x,
			y:player.y,
			number:player.number
		});
	}
	return pack;
}


var Bullet = function(angle){
	var self = Entity();
	self.id = Math.random();
	self.spdX = Math.cos(angle/180*Math.PI) * 10;
	self.spdY = Math.sin(angle/180*Math.PI) * 10;

	self.timer = 0;
	self.toRemove = false;
	var super_update = self.update;
	self.update = function(){
		if(self.timer++ > 100)
			self.toRemove = true;
		super_update();
	}
	Bullet.list[self.id] = self;
	return self;
}
Bullet.list = {};

Bullet.update = function(){
	if(Math.random() < 0.1){
		Bullet(Math.random()*360);
	}

	var pack = [];
	for(var i in Bullet.list){
		var bullet = Bullet.list[i];
		bullet.update();
		pack.push({
			x:bullet.x,
			y:bullet.y,
		});
	}
	return pack;
}

var io = require('socket.io')(serv,{});
io.sockets.on('connection', function(socket){
	socket.id = Math.random();
	SOCKET_LIST[socket.id] = socket;

	Player.onConnect(socket);

	socket.on('disconnect',function(){
		delete SOCKET_LIST[socket.id];
		Player.onDisconnect(socket);
	});




});

setInterval(function(){
	var pack = {
		player:Player.update(),
		bullet:Bullet.update(),
	}

	for(var i in SOCKET_LIST){
		var socket = SOCKET_LIST[i];
		socket.emit('newPositions',pack);
	}
},1000/25);



//index.html
<canvas id="ctx" width="500" height="500" style="border:1px solid #000000;"></canvas>

<script src="https://cdn.socket.io/socket.io-1.4.5.js"></script>
<script>
	var ctx = document.getElementById("ctx").getContext("2d");
	ctx.font = '30px Arial';

	var socket = io();

	socket.on('newPositions',function(data){
		ctx.clearRect(0,0,500,500);
		for(var i = 0 ; i < data.player.length; i++)
			ctx.fillText(data.player[i].number,data.player[i].x,data.player[i].y);

		for(var i = 0 ; i < data.bullet.length; i++)
			ctx.fillRect(data.bullet[i].x-5,data.bullet[i].y-5,10,10);
	});

	document.onkeydown = function(event){
		if(event.keyCode === 68)	//d
			socket.emit('keyPress',{inputId:'right',state:true});
		else if(event.keyCode === 83)	//s
			socket.emit('keyPress',{inputId:'down',state:true});
		else if(event.keyCode === 65) //a
			socket.emit('keyPress',{inputId:'left',state:true});
		else if(event.keyCode === 87) // w
			socket.emit('keyPress',{inputId:'up',state:true});

	}
	document.onkeyup = function(event){
		if(event.keyCode === 68)	//d
			socket.emit('keyPress',{inputId:'right',state:false});
		else if(event.keyCode === 83)	//s
			socket.emit('keyPress',{inputId:'down',state:false});
		else if(event.keyCode === 65) //a
			socket.emit('keyPress',{inputId:'left',state:false});
		else if(event.keyCode === 87) // w
			socket.emit('keyPress',{inputId:'up',state:false});
	}

</script>