ChessGame/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 app = express(); //Routing and middleware setup are done by express ////app has an instance of express
// const server = http.createServer(app);
// const io = socket(server); //socket is used to connect in real time

// const chess = new Chess(); //now all the rules of chess is stored in chess variable
// let players = {};
// let currentPlayer = "w";

// app.set("view engine", "ejs");
// app.use(express.static(path.join(__dirname, "public"))); //by this we can use images and all

// 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; //uniquesocket.on("move", (move) => {} isse  move event record hoga
//       if (chess.turn() === "b" && uniquesocket.id !== players.black) return;

//       const result = chess.move(move); //idhar move event(jo bhi pawn move hua hai wo) valid hai ki nahi  evaluate hoga

//       if (result) {
//         currentPlayer = chess.turn();
//         io.emit("move", move);
//         io.emit("boardState", chess.fen());
//       } else {
//         console.log("Invalid move: ", move); ////consoling in browser
//         uniquesocket.emit("invalidMove", move); ////informing the player that the move is invalid
//       }
//     } catch (err) {
//       console.log(err);
//       uniquesocket.emit("Invalid move: ", move); ////const result = chess.move(move);if this line fails then catch is executed///////timestamp:1:06:06
//     }
//   });
// });

// server.listen(3000, function () {
//   console.log("Listening");
// });
// //3 types of server method
// //server sends the message to the sender itself also, so only the sender can be able to know that the message is sent to  other/s
// //server sends the message to only particular person
// //server send the message to all except sender , this is called broadcasting. Eg:When you are typing in whatsapp, it shows typing to others except the typer



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

const app = express();
const server = http.createServer(app);
const io = socketIo(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", (socket) => {
  console.log("A player connected:", socket.id);

  if (!players.white) {
    players.white = socket.id;
    socket.emit("playerRole", "w");
  } else if (!players.black) {
    players.black = socket.id;
    socket.emit("playerRole", "b");
  } else {
    socket.emit("spectatorRole");
  }

  socket.on("disconnect", () => {
    if (socket.id === players.white) {
      delete players.white;
    } else if (socket.id === players.black) {
      delete players.black;
    }
  });

  socket.on("move", (move) => {
    try {
      if ((chess.turn() === "w" && socket.id !== players.white) ||
          (chess.turn() === "b" && socket.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);
        socket.emit("invalidMove", move);
      }
    } catch (err) {
      console.error(err);
      socket.emit("error", "Invalid move");
    }
  });

  socket.emit("boardState", chess.fen());
});

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