#!/usr/bin/env node
const http = require("http");
const express = require("express");
const socketio = require("socket.io")

const PORT = 8080;

const app = express();
const server = http.Server(app);
const io = socketio(server);

// gameid -> {pl: [socket], started: Bool}
const games = new Map();

function genId() {
	for (let i = 0; i < 10; i++) {
		// 2176782336 == 36^6
		const id = ("000000" + (2176782336 * Math.random() | 0).toString(36)).slice(-6);
		if (!games.has(id)) return id;
	}
	return "";
}

function validId(id) {
	return /^[0-9a-z]{6}$/.test(id);
}

app.get("/", (req, res) => {
	const gameid = genId();
	if (gameid == "") {
		res.sendStatus(500);
		return;
	}
	res.redirect("/game/" + gameid);
});

app.param("gameid", (req, res, next, gameid) => {
	if (!validId(gameid)) {
		res.sendStatus(404);
	} else {
		next();
	}
});

app.get("/game/:gameid", (req, res) => {
	res.sendFile(__dirname + "/game.html");
});

app.get("/game.css", (req, res) => res.sendFile(__dirname + "/game.css"));
app.get("/game.js", (req, res) => res.sendFile(__dirname + "/game.js"));

io.on("connection", (conn) => {
	let gameid, gameobj;
	conn.on("open", (id) => {
		console.log("open " + id);
		if (!validId(id)) {
			console.log("  invalid");
			conn.emit("redirect", "/");
			conn.disconnect(true);
			return;
		}
		gameobj = games.get(id);
		if (gameobj != undefined) {
			if (gameobj.pl.length == 1 && !gameobj.started) {
				console.log("  serve");
				gameid = id;
				gameobj.pl.push(conn);
				gameobj.pl[0].emit("status", "Get ready...");
				gameobj.pl[1].emit("status", "Get ready...");
				gameobj.pl[0].emit("serve", "left", 0.5, 0.5);
				gameobj.pl[1].emit("serve", "right", 0.5, 0.5);
				gameobj.started = true;
				setTimeout(() => {
					if (!gameobj || gameobj.pl.length != 2) return;
					gameobj.pl[0].emit("status", "");
					gameobj.pl[1].emit("status", "");
					gameobj.pl[0].emit("startBall");
					gameobj.pl[1].emit("start");
				}, 2000);
			} else {
				console.log("  full");
				gameobj = undefined;
				conn.emit("status", "Game full! Opening new game...");
				setTimeout(() => {
					conn.emit("redirect", "/");
					conn.disconnect(true);
				}, 2000);
			}
		} else {
			console.log("  new");
			gameid = id;
			gameobj = {pl: [conn], started: false};
			games.set(gameid, gameobj);
			conn.emit("status", "Waiting for other player...");
		}
	});

	conn.on("disconnect", () => {
		if (gameobj == undefined) return;

		console.log("stop " + gameid);

		const newpl = [];
		for (const p of gameobj.pl) {
			if (p != conn) {
				p.emit("stop");
				p.emit("status", "Other player left.");
				setTimeout(() => {
					p.emit("redirect", "/");
					p.disconnect(true);
				}, 2000);
				newpl.push(p);
			}
		}

		if (newpl.length == 0) {
			console.log("  delete");
			games.delete(gameid);
		} else {
			gameobj.pl = newpl;
		}
	});

	conn.on("padvec", (pos, vel) => {
		if (!gameobj) return;
		for (const p of gameobj.pl) {
			if (p != conn) {
				p.emit("padvec", pos, vel);
			}
		}
	});
});

server.listen(PORT, () => console.log("Listening on port " + PORT));