chat_server.js

// chat_server.js
// @authors octopoulo <polluxyz@gmail.com>, Aloril <aloril@iki.fi>
// @version 2022-05-21
/*
globals
console, exports, require
*/
'use strict';

let Module = require('./js/chess-wasm.js'),
	{Stringify} = require('./js/common.js'),
	Net = require('net');

let frc = false,
	LS = console.log,
	port = 8090,
	server = new Net.Server();

server.listen(port, () => {
	LS(`Server listening for connection requests on socket localhost:${port}.`);
});

let chess,
	voting = {}; //indexed by fen, supports 1-2 clients

/**
 * Load chess-wasm
 */
async function loadWasm()
{
	let instance = await Module();
	chess = new instance.Chess();
	LS('chess library loaded');
}

function vote(data)
{
	LS('vote, data=' + Stringify(data));
	if (typeof data.fen == "string") { //needed because fen string here don't match fen strings in Python
	let lst = data.fen.split(" ");
	data.fen = lst[0] + " " + lst[1] + " " + lst[5];
	}
	if (!(data.fen in voting) || typeof data.move != "string" || data.move.length > 5)
	{
		LS('Not found');
		return;
	}
	if (!data.time)
	{
		LS('Old GUI, no voting');
		return;
	}
	let entry = voting[data.fen],
	move = data.move;
	LS('entry: ' + Stringify(entry.votes) + ' ' + Stringify(entry.byIP));
	if (!(move in entry.votes))
	{
		entry.votes[move] = 0;
	}
	if (data.ip in entry.byIP)
	{
		if (entry.byIP[data.ip] == move)
		{
			LS("Same move as earlier: " + move);
			return;
		}
		LS(`Reduce vote: ${entry.byIP[data.ip]} by ${data.ip}`);
		entry.votes[entry.byIP[data.ip]]--;
	}
	entry.votes[move]++;
	entry.byIP[data.ip] = move;
	let msg = Stringify({
		fen: data.fen,
		votes: Object.entries(entry.votes),
	});
	LS(`Sending data: ${msg}.`);
	LS('---');
	entry.socket.write(msg.length.toString().padStart(4, " ") + msg);
}

server.on('connection', async socket => {
	let ip = socket.remoteAddress;
	LS(`A new connection has been established: ${ip}.`);
	if (ip != '::ffff:127.0.0.1')
	{
		LS('Not local connection, closing');
		socket.destroy();
		return;
	}

	if (!chess)
		await loadWasm();

	socket.on('data', chunk => {
		// CHECK THIS: FIX: handle 2 messages in one packet or incomplete packets:
		// Error can triggered by "go movetime 100" for example. Could use same method as chat_engine.read_votes does.
		LS('data');
		let data, text;
		try
		{
			text = chunk.toString();
			data = JSON.parse(text);
		}
		catch (e)
		{
			LS(`bad data: ${data}, text: ${text}`);
			LS(e);
			return;
		}

		if (data.voting != undefined)
		{
			if (data.voting)
			{
				voting[data.fen] = {
					votes: {},
					byIP: {},
					socket: socket
				};
				LS("created empty voting");
			}
			else if (data.fen in voting)
			{
				delete voting[data.fen];
				LS("deleted voting");
			}
		}
		LS(`Data received from client: ${text}`);
	});

	socket.on('end', () => {
		LS('Closing connection with the client');
	});

	socket.on('error', err => {
		LS(`Error: ${err}`);
	});
});

exports.vote = vote;