#!/usr/bin/env node

var aicmd;

if(process.argv.length!=3){
	console.log("Give AI command to run as command line argument.");
	process.exit(1);
}
aicmd=process.argv[2];
console.log("Using AI command '"+aicmd+"'");


var app=require("express")(),
    http=require("http").Server(app),
    io=require("socket.io")(http),
    fs=require("fs"),
    spawn=require("child_process").spawn;

eval(String(fs.readFileSync("common.js")));


var HTTPPORT=8080;

var uniqid=(function(){
	var id=0;
	return function(){return id++;};
})();

app.get("/",function(req,res){
	res.sendFile(__dirname+"/index.html");
});

["index.html","common.js"].forEach(function(fname){
	app.get("/"+fname,function(req,res){
		res.sendFile(__dirname+"/"+fname);
	});
});

var childpids=[];

process.on("exit",function(){
	console.log("Exiting:");
	console.log.apply(console,arguments);
	childpids.forEach(function(pid){process.kill(pid);});
	process.exit();
});
process.on("SIGINT",function(){
	console.log("SIGINT:");
	console.log.apply(console,arguments);
	childpids.forEach(function(pid){process.kill(pid);});
	process.exit();
});

function stopproc(proc){
	var pid=proc.pid;
	console.log("Stopping proc with pid "+pid+", childpids="+JSON.stringify(childpids));
	proc.stdin.write("Quit\n");
	var timeout=setTimeout(function(){
		console.log("Proc with pid "+pid+" didn't stop in time, killing");
		proc.kill();
		var idx=childpids.indexOf(pid); if(idx!=-1)childpids.splice(idx,1);
	},500);
	proc.on("exit",function(){
		clearTimeout(timeout);
		var idx=childpids.indexOf(pid); if(idx!=-1)childpids.splice(idx,1);
	});
}

io.on("connection",function(conn){
	var id=uniqid();
	console.log("New IO connection id "+id);
	var pingtimeout=null;

	var bd=emptyboard();
	var aiplayer=0;

	conn.on("disconnect",function(){
		console.log("Disconnect id "+id);
		if(proc){stopproc(proc);proc=null;}
		if(pingtimeout)clearTimeout(pingtimeout);
	});
	conn.on("ping",function(){ //only enable ping timeouting if a first ping received
		if(pingtimeout)clearTimeout(pingtimeout);
		pingtimeout=setTimeout(function(){
			console.log("Ping timeout on id "+id+"!");
			if(proc){stopproc(proc);proc=null;}
			conn.disconnect(true);
		},4000);
	});
	conn.on("usermove",function(idx){
		idx=+idx;
		if(idx<0||idx>=W*H){
			conn.emit("alert","You sent an invalid move, index "+idx);
			conn.emit("getusermove");
			return;
		}
		var x=idx%W,y=~~(idx/W);
		bd[y][x].c=1-aiplayer;
		bd[y][x].n++;
		bd=stabilise(bd);
		if(countballs(bd)>2){
			var win=checkwin(bd);
			if(win!=-1){
				conn.emit("win",1-aiplayer);
				if(proc){stopproc(proc);proc=null;}
				return;
			}
		}
		proc.stdin.write(x+" "+y+"\n");
		conn.emit("setonturn",aiplayer);
	});


	var proc=spawn("sh",["-c",aicmd],{
		stdio:["pipe","pipe",process.stderr]
	});
	childpids.push(proc.pid);
	var buffer="";
	proc.stdout.on("data",function(data){
		var idx,line,mv,win;
		buffer+=data;
		while((idx=buffer.indexOf("\n"))!=-1){
			line=buffer.slice(0,idx);
			buffer=buffer.slice(idx+1);
			mv=line.split(" ").map(function(s){return parseInt(s,10);});
			if(mv.length!=2||isNaN(mv[0])||isNaN(mv[1])){
				console.log("Invalid move written by AI: '"+line+"'");
				conn.emit("alert","Invalid move written by AI: '"+line+"'");
				mv[0]=0;
				mv[1]=0;
			}
			bd[mv[1]][mv[0]].c=aiplayer;
			bd[mv[1]][mv[0]].n++;
			bd=stabilise(bd);
			conn.emit("applymove",{index:W*mv[1]+mv[0],player:aiplayer});
			if(countballs(bd)>2){
				win=checkwin(bd);
				if(win!=-1){
					conn.emit("win",aiplayer);
					if(proc){stopproc(proc);proc=null;}
					return;
				}
			}
			conn.emit("setonturn",1-aiplayer);
			conn.emit("getusermove");
		}
	});
	proc.stdin.write("A\n-1 -1\n");
	conn.emit("emptyboard");
	conn.emit("setonturn",0);
});

http.listen(HTTPPORT,function(){
	console.log("Listening on http://localhost:"+HTTPPORT);
});