server.js

// server.js
const express = require('express');
const http    = require('http');
const path    = require('path');
const { Server } = require('socket.io');

const app    = express();
const server = http.createServer(app);
const io     = new Server(server);
const PORT   = process.env.PORT || 3000;

// Serve static assets
app.use(express.static(path.join(__dirname, 'public')));
app.get('/',          (req,res) => res.sendFile(path.join(__dirname,'public/index.html')));
app.get('/lobby/:roomId',(req,res) => res.sendFile(path.join(__dirname,'public/lobby.html')));

// Global room → (socket → userId) map
const roomMembers = new Map();

io.on('connection', socket => {
  // Helper to find which room this socket is in
  function getRoom() {
    return [...socket.rooms].find(r => r !== socket.id);
  }

  socket.on('join-room', ({ room, user }) => {
    socket.join(room);

    // ensure map exists
    if (!roomMembers.has(room)) {
      roomMembers.set(room, new Map());
    }
    const members = roomMembers.get(room);
    members.set(socket.id, user);

    // send the new client all existing members
    const existing = Array.from(members.entries()).map(
      ([sid, uid]) => ({ sid, uid })
    );
    socket.emit('existing-members', existing);

    // inform everyone else
    socket.to(room).emit('member-joined', {
      sid: socket.id,
      uid:  user
    });
  });

  socket.on('leave-room', () => {
    const room = getRoom();
    if (!room) return;

    const members = roomMembers.get(room);
    if (members) {
      members.delete(socket.id);
      socket.to(room).emit('member-left', socket.id);

      // clean up empty rooms
      if (members.size === 0) {
        roomMembers.delete(room);
      }
    }
    socket.leave(room);
  });

  socket.on('start-stream', () => {
    const room = getRoom();
    if (room) socket.to(room).emit('stream-started');
  });

  socket.on('stop-stream', () => {
    const room = getRoom();
    if (room) socket.to(room).emit('stream-stopped');
  });

  socket.on('signal', ({ to, data }) => {
    socket.to(to).emit('signal', {
      from: socket.id,
      data
    });
  });

  // If the socket disconnects unexpectedly, clean up
  socket.on('disconnect', () => {
    const room = getRoom();
    if (!room) return;
    const members = roomMembers.get(room);
    if (members) {
      members.delete(socket.id);
      socket.to(room).emit('member-left', socket.id);
      if (members.size === 0) roomMembers.delete(room);
    }
  });
});

server.listen(PORT, () => {
  console.log(`Server listening on http://localhost:${PORT}`);
});