import express from 'express';
import { createServer } from 'http';
import { Server } from 'socket.io';
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

const app = express();
const httpServer = createServer(app);
const io = new Server(httpServer, {
  cors: {
    origin: "*",
    methods: ["GET", "POST"]
  }
});

// Serve static files from the React build (dist)
app.use(express.static(join(__dirname, 'dist')));

// Handle SPA routing - send index.html for any unknown route
app.get('*', (req, res) => {
  res.sendFile(join(__dirname, 'dist', 'index.html'));
});

// Socket.io Signaling for WebRTC
io.on('connection', (socket) => {
  console.log('User connected:', socket.id);

  socket.on('join-room', (roomId) => {
    const room = io.sockets.adapter.rooms.get(roomId);
    const numClients = room ? room.size : 0;

    if (numClients < 10) {
      socket.join(roomId);

      // Get all OTHER users in the room
      const otherUsers = [];
      if (room) {
        room.forEach(id => {
          if (id !== socket.id) otherUsers.push(id);
        });
      }

      // Send list of existing users to the new user
      socket.emit('all-users', otherUsers);

      // Notify others that a new user joined - REMOVED to avoid double notification with user-info
      // socket.to(roomId).emit('user-joined', { signal: null, callerID: socket.id });

    } else {
      socket.emit('full');
      return;
    }

    // Broadcast updated count
    const updatedRoom = io.sockets.adapter.rooms.get(roomId);
    io.to(roomId).emit('room-count', updatedRoom ? updatedRoom.size : 0);
  });

  // Relay WebRTC signals to specific peers
  socket.on('offer', ({ offer, to }) => {
    io.to(to).emit('offer', { offer, from: socket.id });
  });

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

  socket.on('ice-candidate', ({ candidate, to }) => {
    io.to(to).emit('ice-candidate', { candidate, from: socket.id });
  });

  // Relay Captions (Broadcast to room)
  socket.on('caption', ({ text, userName, roomId }) => {
    socket.to(roomId).emit('caption', { text, userName });
  });

  // Relay Chat Messages (Broadcast to room)
  socket.on('chat-message', ({ text, userName, roomId }) => {
    socket.to(roomId).emit('chat-message', { text, userName });
  });

  // Exchange User Info (Broadcast to room)
  socket.on('user-info', ({ userName, roomId }) => {
    // Broadcast to others in the room that this user joined
    socket.to(roomId).emit('user-joined', { userName, callerID: socket.id });
    // Send user info to room
    socket.to(roomId).emit('user-info', { userName, id: socket.id });
  });

  socket.on('disconnecting', () => {
    for (const room of socket.rooms) {
      if (room !== socket.id) {
        // Get current count, minus this socket which is about to leave
        const roomObj = io.sockets.adapter.rooms.get(room);
        const count = roomObj ? roomObj.size - 1 : 0;
        socket.to(room).emit('room-count', count);
        socket.to(room).emit('user-disconnected', socket.id);
        socket.to(room).emit('user-left', { userName: 'A user' });
      }
    }
  });

  socket.on('disconnect', () => {
    console.log('User disconnected');
  });
});

// Use port 7860 for Hugging Face Spaces compatibility, or default to 3000
const PORT = process.env.PORT || 7860;

httpServer.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});