package com.ld.io.netty;

import com.ld.io.api.HeartbeatProvider;
import com.ld.io.api.IoMsgConsumer;
import com.ld.io.api.IoSession;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.io.IOException;

@Sharable
public class ReadMessageHandler extends SimpleChannelInboundHandler<Object> {
    private final InternalLogger logger = InternalLoggerFactory.getInstance(this.getClass());
    private ReceiveMessageThreadPool threadPool;//消息处理线程池
    private NettySessionFactory nettySessionFactory;//会话工厂
    private HeartbeatProvider heartbeatMessageProvider;//心跳数据提供者

    public ReadMessageHandler(IoMsgConsumer messageConsumer, NettySessionFactory nettySessionFactory, HeartbeatProvider heartbeatMessageProvider) {
        this.threadPool = new ReceiveMessageThreadPool(messageConsumer);
        this.nettySessionFactory = nettySessionFactory;
        this.heartbeatMessageProvider = heartbeatMessageProvider;
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        nettySessionFactory.create(new NettyChannel(ctx));
        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        nettySessionFactory.destroy(ctx);
        super.channelInactive(ctx);
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        IoSession session = nettySessionFactory.getSession(ctx);
        threadPool.execute(session, (byte[]) msg);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        logger.error("happened error!", cause);
        Channel channel = ctx.channel();
        if (cause instanceof IOException && channel.isActive()) {
            nettySessionFactory.destroy(ctx);
            ctx.close();
        }
    }

    /**
     * 心跳处理
     * 超时后尝试向客户端发送消息，若发送失败关闭channel
     */
    @Override
    public void userEventTriggered(final ChannelHandlerContext ctx, Object evt) throws Exception {
        if (evt instanceof IdleStateEvent) {
            if (heartbeatMessageProvider == null) {
                return;
            }

            logger.info("Health check time out, the event was triggered");
            IoSession session = nettySessionFactory.getSession(ctx);
            if(null == session){
            	logger.error("no Session by HeartBeat");
            	return;
            }
            byte[] bytes = heartbeatMessageProvider.provide(session);
            
            if(null == bytes){
            	logger.error("no msg by HeartBeat");
            	return;
            }

            ByteBuf buf = Unpooled.copiedBuffer(bytes);
            ctx.writeAndFlush(buf).addListener((ChannelFutureListener) future -> {
                if (!future.isSuccess()) {
                    nettySessionFactory.destroy(ctx);
                    future.channel().close();
                }
            });
        } else {
            super.userEventTriggered(ctx, evt);
        }
    }
}