package com.its.common.cluster.service;

import com.its.common.cluster.codec.ClusterMessageDecoder;
import com.its.common.cluster.codec.ClusterMessageEncoder;
import com.its.common.cluster.config.AbstractClusterConfig;
import com.its.common.cluster.handler.ClusterSlaveHandler;
import com.its.common.cluster.vo.ClusterNode;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.concurrent.GenericFutureListener;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import lombok.Setter;
import lombok.extern.slf4j.Slf4j;

import java.net.InetSocketAddress;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;

@Slf4j
@Getter
@Setter
@RequiredArgsConstructor
public class ClusterSlave implements Callable<Object> {

    private final AbstractClusterSlaveService slaveService;
    private final AbstractClusterConfig clusterConfig;
    private final ClusterNode clusterNode;
    private final ClusterSlaveBootstrapFactory bootstrapFactory;

    private Bootstrap bootstrap = null;
    private ChannelFuture channelFuture = null;
    private String ipAddress;
    private int port;

    @Override
    public Object call() {

        this.ipAddress = this.clusterNode.getIp();
        this.port = this.clusterNode.getPort();

        try {
            initializeBootstrapIfNeeded();

            if (this.clusterConfig.isLogging()) {
                log.info("ClusterNodeId: {}, ClusterSlave.call: Try Connect: toClusterId: {}, [{}.{}]", this.clusterConfig.getId(), this.clusterNode.getId(), this.ipAddress, this.port);
            }

            closePreviousChannel();

            this.channelFuture = this.bootstrap.connect(new InetSocketAddress(this.ipAddress, this.port));

            // 채널 연결 리스너 등록
            this.channelFuture.addListener(new GenericFutureListener<ChannelFuture>() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    channelOpen(future);
                }
            });

            // 채널 연결 종료 리스너 등록
            this.channelFuture.channel().closeFuture().addListener(new GenericFutureListener<ChannelFuture>() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    channelClosed(future);
                }
            });
            return this.channelFuture != null && this.channelFuture.isSuccess();
        } catch (Exception e) {
            log.error("ClusterNodeId: {}, ClusterSlave.call: Connection error toClusterId: {}, [{}.{}], Exception: {}",
                    this.clusterConfig.getId(), this.clusterNode.getId(), this.ipAddress, this.port, e.getMessage(), e);
            return false;
        }
    }

    private void initializeBootstrapIfNeeded() {
        if (this.bootstrap != null) {
            return;
        }

        if (this.clusterConfig.isLogging()) {
            log.info("ClusterNodeId: {}, ClusterSlave.call: Startup: toClusterId: {}, [{}.{}]", this.clusterConfig.getId(), this.clusterNode.getId(), this.ipAddress, this.port);
        }

        this.bootstrap = bootstrapFactory.createBootstrap();
        this.bootstrap.option(ChannelOption.SO_REUSEADDR, true);
        this.bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 5000);

        // 바인딩 로컬 포트 설정(설정파일에 등록된 바인딩 포트번호 + 서버 ID), 따라서 하나의 서버에 여러 개의 클러스터 서버가 존재할 수 있다.
        // 주의) 하나의 서버에 여러 개의 클러스터 서버가 존재할 경우, 바인딩 포트는 위의 규칙에 속하지 않는 포트번호를 할당해야 한다.
        this.bootstrap.localAddress(new InetSocketAddress(port + clusterConfig.getId()));

        this.bootstrap.handler(new ChannelInitializer<SocketChannel>() {
            @Override
            protected void initChannel(SocketChannel ch) {
                if (clusterConfig.isPacketLogging()) {
                    ch.pipeline().addLast(new LoggingHandler(LogLevel.INFO));
                }
                ch.pipeline().addLast(new IdleStateHandler(10, 0, 0, TimeUnit.SECONDS));
                ch.pipeline().addLast(new LengthFieldBasedFrameDecoder(65536, 0, 4));
                ch.pipeline().addLast(new ClusterMessageDecoder(clusterNode, clusterConfig));
                ch.pipeline().addLast(new ClusterMessageEncoder(clusterNode, clusterConfig));
                ch.pipeline().addLast(new ClusterSlaveHandler(clusterNode, slaveService));
            }
        });
    }

    private void closePreviousChannel() {
        if (this.channelFuture != null && this.channelFuture.channel().isOpen()) {
            this.channelFuture.channel().close();
            this.channelFuture = null;
        }
    }

    /**
     * 연결 성공시 처리 이벤트
     */
    protected void channelOpen(ChannelFuture future) {
        if (future.isSuccess()) {
            Channel channel = future.channel();
            channel.attr(AbstractClusterConfig.CLUSTER_ATTRIBUTE_KEY).set(this.clusterNode);
            this.clusterNode.getSyncState().connect(channel);

            if (this.clusterConfig.isLogging()) {
                log.info("ClusterNodeId: {}, ClusterSlave.channelOpen: toClusterId: {}, [{}.{}], Channel: {}", this.clusterConfig.getId(), this.clusterNode.getId(), this.ipAddress, this.port, channel);
            }
        }
        else {
            if (this.clusterConfig.isLogging()) {
                log.warn("ClusterNodeId: {}, ClusterSlave.channelOpen: toClusterId: {}, [{}.{}], Failed: {}", this.clusterConfig.getId(), clusterNode.getId(), clusterNode.getIp(), clusterNode.getPort(), future.cause().getMessage());
            }
        }
    }

    /**
     * 연결 종료시 처리 이벤트
     */
    protected synchronized void channelClosed(ChannelFuture future) {
        Channel channel = future.channel();

        if (this.clusterConfig.isLogging()) {
            log.warn("ClusterNodeId: {}, ClusterSlave.channelClosed: toClusterId: {}, [{}.{}], Channel: {}", this.clusterConfig.getId(), this.clusterNode.getId(), this.ipAddress, this.port, channel);
        }

        channel.attr(AbstractClusterConfig.CLUSTER_ATTRIBUTE_KEY).set(null);
        this.clusterNode.getSyncState().disConnect();

        if (channel.isOpen()) {
            channel.close();
        }

        channel.eventLoop().schedule(this, 5, TimeUnit.SECONDS);
    }

}