package com.unisinsight.project.udp;

import cn.hutool.extra.spring.SpringUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

@Component
public class UDPServer {
    
    private static final Logger logger = LoggerFactory.getLogger(UDPServer.class);
    
    private static final int PORT = 8115;
    
    private DatagramSocket socket;
    private Thread serverThread;
    private volatile boolean running = false;
    
    @PostConstruct
    public void start() {
        try {
            socket = new DatagramSocket(PORT);
            running = true;
            
            serverThread = new Thread(() -> {
                byte[] buffer = new byte[1024];
                
                while (running) {
                    try {
                        DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
                        socket.receive(packet);
                        
                        // 处理接收到的数据
                        handlePacket(packet);
                    } catch (IOException e) {
                        if (running) {
                            logger.error("UDP服务器接收数据时发生错误", e);
                        }
                    }
                }
            });
            
            serverThread.start();
            logger.info("UDP服务器已启动，监听端口: {}", PORT);
        } catch (SocketException e) {
            logger.error("UDP服务器启动失败，端口: {}", PORT, e);
        }
    }
    
    private void handlePacket(DatagramPacket packet) {
        try {
            // 获取客户端地址和端口
            InetAddress clientAddress = packet.getAddress();
            int clientPort = packet.getPort();
            
            // 获取主机IP地址
            String hostIP = InetAddress.getLocalHost().getHostAddress();
            String serverPort = SpringUtil.getProperty("server.port");
            // 将主机IP地址发送回客户端
            byte[] responseData = hostIP.getBytes();
            DatagramPacket responsePacket = new DatagramPacket(responseData, responseData.length, clientAddress, clientPort);
            socket.send(responsePacket);


            logger.info("已向客户端 {}/{} 返回主机IP地址: {}:{}", clientAddress.getHostAddress(), clientPort, hostIP, serverPort);
        } catch (UnknownHostException e) {
            logger.error("无法获取本机IP地址", e);
        } catch (IOException e) {
            logger.error("向客户端发送数据时发生错误", e);
        }
    }
    
    @PreDestroy
    public void stop() {
        running = false;
        if (socket != null && !socket.isClosed()) {
            socket.close();
        }
        if (serverThread != null) {
            serverThread.interrupt();
        }
        logger.info("UDP服务器已停止");
    }
}