app.js

const express = require("express");
const socket = require("socket.io");
const http = require("http");
const { Chess } = require("chess.js");
const path = require("path");
const { log } = require("console");


const app = express();

const server = http.createServer(app);

const io = socket(server);
const chess = new Chess();

let players = {};
let currentPlayer = "w";

app.set("view engine", "ejs");
app.use(express.static(path.join(__dirname, "public")));

app.get("/", (req, res) => {
    res.render("index", { title: "Chess Game" });
});

io.on("connection", function(uniquesocket) {
    console.log("connected");
    if (!players.white) {
        players.white = uniquesocket.id;
        uniquesocket.emit("playerRole", "w")
    } else if (!players.black) {
        players.black = uniquesocket.id;
        uniquesocket.emit("playerRole", "b");
    } else {
        uniquesocket.emit("spectatorRole");
    }

    uniquesocket.on("disconnect", function() {
        if (uniquesocket.id === players.white) {
            delete players.white;
        } else if (uniquesocket.id === players.black) {
            delete players.black;
        }
    });
    uniquesocket.on("move", (move) => {
        try {
            if (chess.turn() === "w" && uniquesocket.id !== players.white) return;
            if (chess.turn() === "b" && uniquesocket.id !== players.black) return;

            const result = chess.move(move);
            if (result) {
                currentPlayer = chess.turn();
                io.emit("move", move);
                io.emit("boardState", chess.fen())
            } else {
                console.log("Invalid move :", move);
                uniquesocket.emit("invalidMove", move);
            }
        } catch (err) {
            console.log(err);
            uniquesocket.emit("Invalid move : ", move);

        }
    })
});

server.listen(3000, function() {
    console.log(" listening on port 3000");
});