server/src/index.js

const express = require('express');
const http = require('http');
const path = require('path');
const https = require('https');
const { Server } = require('socket.io');
const Room = require('./game/Room');
const { PORT } = require('../config');

const app = express();
const server = http.createServer(app);
const io = new Server(server, {
  cors: {
    origin: '*',
  },
});

// Serve client build
app.use(express.static(path.join(__dirname, '../../client')));

// Health check endpoint – used by Render and uptime monitors to prevent sleep
app.get('/health', (req, res) => {
  res.status(200).json({ status: 'ok', uptime: Math.floor(process.uptime()) });
});

const room = new Room(io);

io.on('connection', (socket) => {
  console.log('Người chơi kết nối:', socket.id);

  socket.on('join', (name) => {
    const player = room.addPlayer(socket.id, name);
    socket.emit('joined', { id: player.id });
  });

  socket.on('input', ({ x, y, boost }) => {
    room.handleInput(socket.id, x, y, boost);
  });

  socket.on('disconnect', () => {
    console.log('Người chơi rời đi:', socket.id);
    room.removePlayer(socket.id);
  });
});

room.start();

server.listen(PORT, '0.0.0.0',() => {
  console.log(`Server đang chạy tại port ${PORT}`);

  // Self-ping every 14 minutes to prevent Render free tier from sleeping
  const RENDER_URL = process.env.RENDER_EXTERNAL_URL;
  if (RENDER_URL) {
    const pingUrl = `${RENDER_URL}/health`;
    setInterval(() => {
      const protocol = pingUrl.startsWith('https') ? https : require('http');
      protocol.get(pingUrl, (res) => {
        console.log(`[keep-alive] ping ${pingUrl} → ${res.statusCode}`);
      }).on('error', (err) => {
        console.warn('[keep-alive] ping failed:', err.message);
      });
    }, 14 * 60 * 1000); // 14 minutes
    console.log(`[keep-alive] Self-ping enabled → ${pingUrl}`);
  } else {
    console.log('[keep-alive] RENDER_EXTERNAL_URL not set – skipping self-ping');
  }
});