package com.xcong.excoin.netty.handler;


import com.xcong.excoin.netty.common.ChannelManager;
import com.xcong.excoin.netty.common.Contans;
import com.xcong.excoin.netty.common.NettyTools;
import com.xcong.excoin.netty.dispatch.MsgDispatch;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.util.CharsetUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.util.Date;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import static io.netty.handler.codec.http.HttpUtil.isKeepAlive;

/**
 * @author wzy
 * @email wangdoubleone@gmail.com
 * @date 2019-05-06
 */
@Slf4j
@Component
@ChannelHandler.Sharable
public class WebSocketServerHandler extends ChannelInboundHandlerAdapter {

    private final ConcurrentMap<String, Integer> pingTimes = new ConcurrentHashMap<>();

    private static final int MAX_UN_REC_PING_TIMES = 3;

    private WebSocketServerHandshaker handshaker;

    @Resource(name = "msgDispatch")
    private MsgDispatch msgDispatch;

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        log.info("[websocket客户端连入服务器]-->{}", ctx.channel().id());
        ChannelManager.addWebSocketChannel(ctx.channel());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        log.info("[离开websocket服务器]-->{}", ctx.channel().id());
        ChannelManager.removeWebSocketChannel(ctx.channel());
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
//        LogUtil.info("[websocket服务器收到消息]-->{}, {}", ctx.channel().id(), msg);
        if (msg instanceof FullHttpRequest) {
            // 以http请求形式接入，但是走的是websocket
            handleHttpRequest(ctx, (FullHttpRequest) msg);
        } else if (msg instanceof WebSocketFrame) {
            // 处理websocket客户端的消息
            handlerWebSocketFrame(ctx, (WebSocketFrame) msg);

            WebSocketFrame frame = (WebSocketFrame) msg;
            String content;
            try {
                content = ((TextWebSocketFrame) frame).text();
                if (content.contains(Contans.HEART_BEAT)) {
                    resetTimes(ctx.channel());
                } else {
                    this.msgDispatch.webSocketDispatch(ctx, content);
                }
            } catch (ClassCastException e) {
                content = ((CloseWebSocketFrame) frame).reasonText();
                ctx.writeAndFlush(new TextWebSocketFrame(content));
            }
        }
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        log.info("[触发器触发]");
//        super.userEventTriggered(ctx, evt);
        if (evt instanceof IdleStateEvent) {
            IdleStateEvent event = (IdleStateEvent) evt;
            if (event.state() == IdleState.READER_IDLE) {

            } else if (event.state() == IdleState.WRITER_IDLE) {
                /*写超时*/
                ctx.channel().writeAndFlush(NettyTools.webSocketBytes(Contans.HEART_BEAT));
                Integer times = pingTimes.get(ctx.channel().id().asShortText());
                if (times == null) {
                    times = 0;
                }
                /*读超时*/
                log.info("===服务端===({}写超时, {})", ctx.channel().id().asShortText(), times);
                // 失败计数器次数大于等于3次的时候，关闭链接，等待client重连
                if (times >= MAX_UN_REC_PING_TIMES) {
                    log.info("===服务端===(写超时，关闭chanel)");
                    // 连续超过N次未收到client的ping消息，那么关闭该通道，等待client重连
                    ctx.channel().close();
                } else {
                    // 失败计数器加1
                    times++;
                    pingTimes.remove(ctx.channel().id().asShortText());
                    pingTimes.put(ctx.channel().id().asShortText(), times);
                }
            } else if (event.state() == IdleState.ALL_IDLE) {
                /*总超时*/
                System.out.println("===服务端===(ALL_IDLE 总超时)");
            }
        }
    }

    private void resetTimes(Channel channel) {
        pingTimes.remove(channel.id().asShortText());
        pingTimes.put(channel.id().asShortText(), 0);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        log.error("[websocket服务器发生异常]-->{},{}#", ctx.channel().id(), cause);
        super.exceptionCaught(ctx, cause);
    }


    private void handlerWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) {
        // 判断是否关闭链路的指令
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
            return;
        }
        // 判断是否ping消息
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        // 本例程仅支持文本消息，不支持二进制消息
        if (!(frame instanceof TextWebSocketFrame)) {
            System.out.println("本例程仅支持文本消息，不支持二进制消息");
            throw new UnsupportedOperationException(String.format("%s frame types not supported", frame.getClass().getName()));
        }
        // 返回应答消息
        String request = ((TextWebSocketFrame) frame).text();
        TextWebSocketFrame tws = new TextWebSocketFrame(new Date().toString() + ctx.channel().id() + "：" + request);
        // 群发
        // ChannelSupervise.send2All(tws);
        // 返回【谁发的发给谁】
        // ctx.channel().writeAndFlush(tws);
    }

    /**
     * 唯一的一次http请求，用于创建websocket
     */
    private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) {
        InetSocketAddress inetSocketAddress = (InetSocketAddress) ctx.channel().remoteAddress();
        InetAddress inetAddress = inetSocketAddress.getAddress();
        String ip = inetAddress.getHostAddress();
        int port = inetSocketAddress.getPort();

        //要求Upgrade为websocket，过滤掉get/Post
        if (!req.decoderResult().isSuccess() || (!"websocket".equals(req.headers().get("Upgrade")))) {
            //若不是websocket方式，则创建BAD_REQUEST的req，返回给客户端
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory("ws://" + ip + ":" + port + "/websocket", null, false);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
        } else {
            handshaker.handshake(ctx.channel(), req);
        }
    }

    /**
     * 拒绝不合法的请求，并返回错误信息
     */
    private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, DefaultFullHttpResponse res) {
        // 返回应答给客户端
        if (res.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(),
                    CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }
        //服务端向客户端发送数据
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        // 如果是非Keep-Alive，关闭连接
        if (!isKeepAlive(req) || res.status().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }
}