const express = require('express');
const http = require('http');
const socketIo = require('socket.io');

const app = express();
const server = http.createServer(app);
const io = socketIo(server, {
    cors: {
        origin: '*',
        methods: ['GET', 'POST'],
        credentials: true,
    },
});

io.on('connection', (socket) => {
    console.log('Client connected');

    socket.on('ping', (data) => {
        // 接收到客户端发送的 ping 消息，可以记录接收时间并返回响应
        const receiveTime = new Date().getTime();
        //console.log(`Received ping from client: ${data}`);
        socket.emit('pong', { data, receiveTime });
    });

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

const PORT = 9000;
server.listen(PORT, () => {
    console.log(`Server is running on port ${PORT}`);
});