package org.springblade.jfpt.nettyTcpServer;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.ServerSocketChannel;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.logging.LoggingHandler;

import java.nio.ByteOrder;
import java.nio.charset.Charset;


public class TcpServer {
	private int port;
	private ServerSocketChannel serverSocketChannel;

	public TcpServer(int port){
		this.port = port;
		bind();
	}

	private void bind() {
		Thread thread = new Thread(new Runnable() {
			@Override
			public void run() {
				//服务端要建立两个group，一个负责接收客户端的连接，一个负责处理数据传输
				//连接处理group
				EventLoopGroup boss = new NioEventLoopGroup();
				//事件处理group
				EventLoopGroup worker = new NioEventLoopGroup();
				ServerBootstrap bootstrap = new ServerBootstrap();
				// 绑定处理group
				bootstrap.group(boss, worker).channel(NioServerSocketChannel.class)
					//保持连接数
					.option(ChannelOption.SO_BACKLOG, 128)
					//有数据立即发送
					.option(ChannelOption.TCP_NODELAY, true)
					//保持连接
					.childOption(ChannelOption.SO_KEEPALIVE, true)
					.childOption(ChannelOption.RCVBUF_ALLOCATOR, new FixedRecvByteBufAllocator(512*250))
					.childHandler(new NettyChannelHandler());

				//绑定端口，同步等待成功
				ChannelFuture future;
				try {
					future = bootstrap.bind(port).sync();
					if (future.isSuccess()) {
						serverSocketChannel = (ServerSocketChannel) future.channel();
						System.out.println("服务端启动成功，端口："+port);
					} else {
						System.out.println("服务端启动失败！");
					}

					//等待服务监听端口关闭,就是由于这里会将线程阻塞，导致无法发送信息，所以我这里开了线程
					future.channel().closeFuture().sync();
				} catch (Exception e) {
					e.printStackTrace();
				}
				finally {
					//优雅地退出，释放线程池资源
					boss.shutdownGracefully();
					worker.shutdownGracefully();
				}
			}
		});
		thread.start();
	}



	private class NettyChannelHandler extends ChannelInitializer<SocketChannel> {

		@Override
		protected void initChannel(SocketChannel socketChannel)
			throws Exception {
			//socketChannel.pipeline().addLast(new MyNettyDecode());
			//socketChannel.pipeline().addLast(new StringDecoder(Charset.forName("UTF-8")));
			//socketChannel.pipeline().addLast("decoder", new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0,4,0,4));
			//socketChannel.pipeline().addLast("encoder", new LengthFieldPrepender(4, false));
			socketChannel.pipeline().addLast(new TcpServerHandler());
		}
	}

}