package com.zhentao.information.config;

import com.zhentao.information.handler.WebSocketHandler;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.stream.ChunkedWriteHandler;
import io.netty.handler.timeout.IdleStateHandler;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.annotation.Resource;
import java.util.concurrent.TimeUnit;

/**
 * Netty服务器配置类
 * 配置WebSocket服务器的启动参数和处理器链
 */
@Slf4j
@Configuration
public class NettyConfig {

    /**
     * WebSocket服务器端口
     */
    @Value("${netty.websocket.port}")
    private int port;

    /**
     * WebSocket消息处理器
     */
    @Resource
    private WebSocketHandler webSocketHandler;

    /**
     * 配置并启动Netty服务器
     * @return ServerBootstrap实例
     */
    @Bean
    public ServerBootstrap serverBootstrap() {
        // 创建主从线程组
        // bossGroup用于接收客户端连接
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        // workerGroup用于处理客户端数据
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        
        // 创建服务器启动对象
        ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(bossGroup, workerGroup)
                // 设置服务器通道实现
                .channel(NioServerSocketChannel.class)
                // 设置线程队列等待连接个数
                .option(ChannelOption.SO_BACKLOG, 128)
                // 设置保持活动连接状态
                .childOption(ChannelOption.SO_KEEPALIVE, true)
                // 禁用Nagle算法，减少延迟
                .childOption(ChannelOption.TCP_NODELAY, true)
                // 设置处理器
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel ch) {
                        // 获取管道
                        ch.pipeline()
                                // HTTP编解码器
                                .addLast(new HttpServerCodec())
                                // 支持大数据流
                                .addLast(new ChunkedWriteHandler())
                                // HTTP消息聚合器
                                .addLast(new HttpObjectAggregator(65536))
                                // 调整心跳检测时间：30秒没有收到消息就触发
                                .addLast(new IdleStateHandler(30, 0, 0, TimeUnit.SECONDS))
                                // WebSocket协议处理器
                                .addLast(new WebSocketServerProtocolHandler("/ws", null, true, 65536))
                                // 自定义消息处理器
                                .addLast(webSocketHandler);
                    }
                });
        
        try {
            // 绑定端口并启动服务器
            bootstrap.bind(port).sync();
            log.info("Netty WebSocket服务器启动成功，端口：{}", port);
        } catch (InterruptedException e) {
            log.error("Netty WebSocket服务器启动失败", e);
            Thread.currentThread().interrupt();
        }
        
        return bootstrap;
    }
}