package com.zksy.pole.MQTTServer.callBack;

import com.alibaba.fastjson.JSONObject;

import com.zksy.pole.MQTTServer.config.MQTTServerProperties;
import com.zksy.pole.MQTTServer.server.MQTTServer;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.handler.codec.mqtt.*;
import lombok.RequiredArgsConstructor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.zksy.pole.MQTTServer.channel.MQTTDeviceManerger.MQTTdeviceAdd;
import static com.zksy.pole.MQTTServer.channel.MQTTDeviceManerger.MQTTdeviceRemove;
import io.netty.handler.codec.*;
/**
 * 大黄
 */
@Component
@RequiredArgsConstructor
public class BootNettyMqttMsgBack {

	private static final Logger log =  LoggerFactory.getLogger(BootNettyMqttMsgBack.class);
	private final MQTTServerProperties MQTTserverProperties;

	/**
	 * 	确认连接请求
	 * @param channel
	 * @param mqttMessage
	 */
	public void connack (Channel channel, MqttMessage mqttMessage) {
		MqttConnectMessage mqttConnectMessage = (MqttConnectMessage) mqttMessage;
		MqttFixedHeader mqttFixedHeaderInfo = mqttConnectMessage.fixedHeader();
		MqttConnectVariableHeader mqttConnectVariableHeaderInfo = mqttConnectMessage.variableHeader();

		//	构建返回报文， 可变报头
		MqttConnAckVariableHeader mqttConnAckVariableHeaderBack = new MqttConnAckVariableHeader(MqttConnectReturnCode.CONNECTION_ACCEPTED, mqttConnectVariableHeaderInfo.isCleanSession());
		//	构建返回报文， 固定报头
		MqttFixedHeader mqttFixedHeaderBack = new MqttFixedHeader(MqttMessageType.CONNACK,mqttFixedHeaderInfo.isDup(), MqttQoS.AT_MOST_ONCE, mqttFixedHeaderInfo.isRetain(), 0x02);
		//	构建CONNACK消息体
		MqttConnAckMessage connAck = new MqttConnAckMessage(mqttFixedHeaderBack, mqttConnAckVariableHeaderBack);
		//log.info("back--"+connAck.toString());
		log.debug("设备上线,channelId：{}", channel.id());
		MQTTdeviceAdd(channel);
		channel.writeAndFlush(connAck);
	}
	public void disconnack (Channel channel, MqttMessage mqttMessage) {
		MqttConnectMessage mqttConnectMessage = (MqttConnectMessage) mqttMessage;
		MqttFixedHeader mqttFixedHeaderInfo = mqttConnectMessage.fixedHeader();
		MqttConnectVariableHeader mqttConnectVariableHeaderInfo = mqttConnectMessage.variableHeader();
		//	构建返回报文， 可变报头
		MqttConnAckVariableHeader mqttConnAckVariableHeaderBack = new MqttConnAckVariableHeader(MqttConnectReturnCode.CONNECTION_REFUSED_BANNED, mqttConnectVariableHeaderInfo.isCleanSession());
		//	构建返回报文， 固定报头
		MqttFixedHeader mqttFixedHeaderBack = new MqttFixedHeader(MqttMessageType.DISCONNECT,mqttFixedHeaderInfo.isDup(), MqttQoS.AT_MOST_ONCE, mqttFixedHeaderInfo.isRetain(), 0x02);
		//	构建CONNACK消息体
		MqttConnAckMessage connAck = new MqttConnAckMessage(mqttFixedHeaderBack, mqttConnAckVariableHeaderBack);
		//log.info("back--"+connAck.toString());
		channel.writeAndFlush(connAck);
		log.debug("设备下线,channelId：{}", channel.id());
		MQTTdeviceRemove(channel);
	}

	/**
	 * 	根据qos发布确认
	 * @param channel
	 * @param mqttMessage
	 */
	public  void puback (Channel channel, MqttMessage mqttMessage) throws InterruptedException {
		MqttPublishMessage mqttPublishMessage = (MqttPublishMessage) mqttMessage;
		MqttFixedHeader mqttFixedHeaderInfo = mqttPublishMessage.fixedHeader();
		Object obj= mqttMessage.variableHeader();
		MqttPublishVariableHeader variableHeader=(MqttPublishVariableHeader)obj;
		String topicName=variableHeader.topicName();
		System.err.println("topicName========"+topicName);
		MqttQoS qos =  mqttFixedHeaderInfo.qosLevel();
		//注意：	readableBytes会改变写指针位置，使后续推送数据时，读取数据为空，需要重置	读指针
        byte[] headBytes = new byte[mqttPublishMessage.payload().readableBytes()];
        mqttPublishMessage.payload().readBytes(headBytes);
        String data = new String(headBytes);
        System.out.println("收到数据-->"+data);
		//重置读取的指针
		mqttPublishMessage.payload().resetReaderIndex();
		//（qos= 0最多一次的传输，1至少一次的传输，2: 只有一次的传输）
        switch (qos) {
	        case AT_MOST_ONCE: 		//	至多一次
				// 构建自定义应答消息
				MqttFixedHeader customFixedHeader = new MqttFixedHeader(MqttMessageType.PUBLISH, false, MqttQoS.AT_MOST_ONCE, false, 0x02);
				MqttPublishVariableHeader customVariableHeader = new MqttPublishVariableHeader("down/light/ack/40005274", 0); // 使用0作为packetId，因为这里不需要确认
				JSONObject jsonObject = new JSONObject();
				jsonObject.put("flag", 1);
				jsonObject.put("cmd", 1111);
				byte[] customPayload = jsonObject.toString().getBytes(StandardCharsets.UTF_8);
				ByteBuf customByteBuf = Unpooled.wrappedBuffer(customPayload);
				MqttPublishMessage customMessage = new MqttPublishMessage(customFixedHeader, customVariableHeader, customByteBuf);

				// 发送自定义应答消息给网关
				if (channel != null) {
					channel.writeAndFlush(customMessage);
				} else {
					log.warn("网关通道未找到，无法发送应答消息");
				}
	            break;
			// QoS 1: 发送PUBACK
	        case AT_LEAST_ONCE:		//	至少一次
	    		//	构建返回报文， 可变报头
	    		MqttMessageIdVariableHeader mqttMessageIdVariableHeaderBack = MqttMessageIdVariableHeader.from(mqttPublishMessage.variableHeader().packetId());
	    		//	构建返回报文， 固定报头
	    		MqttFixedHeader mqttFixedHeaderBack = new MqttFixedHeader(MqttMessageType.PUBACK,mqttFixedHeaderInfo.isDup(), MqttQoS.AT_MOST_ONCE, mqttFixedHeaderInfo.isRetain(), 0x02);
	    		//	构建PUBACK消息体
	    		MqttPubAckMessage pubAck = new MqttPubAckMessage(mqttFixedHeaderBack, mqttMessageIdVariableHeaderBack);
	    		log.info("back--"+pubAck.toString());
	    		channel.writeAndFlush(pubAck);
				//推送到订阅的客户端
				subscribSend(mqttMessage,channel);
	            break;
			// QoS 2: 发送PUBREC
	        case EXACTLY_ONCE:		//	刚好一次
	            //	构建返回报文， 固定报头
	        	MqttFixedHeader mqttFixedHeaderBack2 = new MqttFixedHeader(MqttMessageType.PUBREC,false, MqttQoS.AT_LEAST_ONCE,false,0x02);
	            //	构建返回报文， 可变报头
	            MqttMessageIdVariableHeader mqttMessageIdVariableHeaderBack2 = MqttMessageIdVariableHeader.from(mqttPublishMessage.variableHeader().packetId());
	            MqttMessage mqttMessageBack = new MqttMessage(mqttFixedHeaderBack2,mqttMessageIdVariableHeaderBack2);
				//服务端收到publis的QoS2的消息之后，服务端需要保存一个msgid的记录，并且进入一个状态，
				// 即之后不管来了几个这个msgid的消息，都不管他，认为是重复的，丢弃。
				//接收到publish的QoS2消息之后，不能马上投递给上层，而是在本地做持久化，将消息保存起来。
				int mqttMessageId=mqttPublishMessage.variableHeader().packetId();
				if(!MQTTServer.mqttMessageIdMap.containsKey(mqttMessageId)){
					//不存在此消息，将此消息暂存 //todo 这里可以换成redis做缓存
					MQTTServer.mqttMessageIdMap.put(mqttMessageId, mqttMessage);
					log.info("消息ID"+mqttMessageId+"-->Qos2级别消息，消息缓存");
				}else{
					//重复发送消息，直接返回
					log.info(mqttPublishMessage.variableHeader().packetId()+"消息重复："+mqttPublishMessage.fixedHeader().isDup());
					return;
				}

	    		channel.writeAndFlush(mqttMessageBack);
	            break;
			default:
				break;
        }
	}

	/**
	 * 	发布完成 qos2
	 * @param channel
	 * @param mqttMessage
	 */
	public  void pubcomp (Channel channel, MqttMessage mqttMessage) {
		System.out.println("==========发布完成==========");
        MqttMessageIdVariableHeader messageIdVariableHeader = (MqttMessageIdVariableHeader) mqttMessage.variableHeader();
        //	构建返回报文， 固定报头
    	MqttFixedHeader mqttFixedHeaderBack = new MqttFixedHeader(MqttMessageType.PUBCOMP,false, MqttQoS.AT_MOST_ONCE,false,0);
        //	构建返回报文， 可变报头
        MqttMessageIdVariableHeader mqttMessageIdVariableHeaderBack = MqttMessageIdVariableHeader.from(messageIdVariableHeader.messageId());
        MqttMessage mqttMessageBack = new MqttMessage(mqttFixedHeaderBack,mqttMessageIdVariableHeaderBack);
		//log.info("back--"+mqttMessageBack.toString());
		channel.writeAndFlush(mqttMessageBack);
	}

	/**
	 * 	订阅确认
	 * @param channel
	 * @param mqttMessage
	 */
	public  void suback(Channel channel, MqttMessage mqttMessage) {
		System.out.println("=============客户端订阅主题===================");
		MqttSubscribeMessage mqttSubscribeMessage = (MqttSubscribeMessage) mqttMessage;
		MqttMessageIdVariableHeader messageIdVariableHeader = mqttSubscribeMessage.variableHeader();
		//	构建返回报文， 可变报头
		MqttMessageIdVariableHeader variableHeaderBack = MqttMessageIdVariableHeader.from(messageIdVariableHeader.messageId());
		Set<String> topics = mqttSubscribeMessage.payload().topicSubscriptions().stream().map(mqttTopicSubscription -> mqttTopicSubscription.topicName()).collect(Collectors.toSet());
		//log.info(topics.toString());
		List<Integer> grantedQoSLevels = new ArrayList<>(topics.size());
		for (int i = 0; i < topics.size(); i++) {
			grantedQoSLevels.add(mqttSubscribeMessage.payload().topicSubscriptions().get(i).qualityOfService().value());
			System.out.println("topics=========================="+topics);
		}
		//	构建返回报文	有效负载
		MqttSubAckPayload payloadBack = new MqttSubAckPayload(grantedQoSLevels);
		//	构建返回报文	固定报头
		MqttFixedHeader mqttFixedHeaderBack = new MqttFixedHeader(MqttMessageType.SUBACK, false, MqttQoS.AT_MOST_ONCE, false, 2+topics.size());
		//	构建返回报文	订阅确认
		MqttSubAckMessage subAck = new MqttSubAckMessage(mqttFixedHeaderBack,variableHeaderBack, payloadBack);
		channel.writeAndFlush(subAck);
	}

	/**
	 * 	取消订阅确认
	 * @param channel
	 * @param mqttMessage
	 */
	public  void unsuback(Channel channel, MqttMessage mqttMessage) {
		MqttMessageIdVariableHeader messageIdVariableHeader = (MqttMessageIdVariableHeader) mqttMessage.variableHeader();
		//	构建返回报文	可变报头
		MqttMessageIdVariableHeader variableHeaderBack = MqttMessageIdVariableHeader.from(messageIdVariableHeader.messageId());
		//	构建返回报文	固定报头
		MqttFixedHeader mqttFixedHeaderBack = new MqttFixedHeader(MqttMessageType.UNSUBACK, false, MqttQoS.AT_MOST_ONCE, false, 2);
		//	构建返回报文	取消订阅确认
		MqttUnsubAckMessage unSubAck = new MqttUnsubAckMessage(mqttFixedHeaderBack,variableHeaderBack);
		channel.writeAndFlush(unSubAck);
	}

	/**
	 * 	心跳响应
	 * @param channel
	 * @param mqttMessage
	 */
	public  void pingresp (Channel channel, MqttMessage mqttMessage) {
		System.out.println("-----------心跳响应-------------");
		//	心跳响应报文	11010000 00000000  固定报文
		MqttFixedHeader fixedHeader = new MqttFixedHeader(MqttMessageType.PINGRESP, false, MqttQoS.AT_MOST_ONCE, false, 0);
		MqttMessage mqttMessageBack = new MqttMessage(fixedHeader);
		channel.writeAndFlush(mqttMessageBack);
	}

	/**
	 * 订阅推送
	 */
	public  void subscribSend(MqttMessage mqttMessage,Channel channel){
		MqttPublishMessage mqttPublishMessage = (MqttPublishMessage) mqttMessage;
		Object obj=mqttMessage.variableHeader();
		MqttPublishVariableHeader variableHeader=(MqttPublishVariableHeader)obj;
		String topicName=variableHeader.topicName();
		System.err.println("topicName========"+topicName);
		int packetId=variableHeader.packetId();
		//固定消息头 注意此处的消息类型PUBLISH mqtt协议
		MqttFixedHeader FixedHeader = new MqttFixedHeader(MqttMessageType.PUBLISH,false, MqttQoS.AT_MOST_ONCE,false,0);
		//可变消息头
		MqttPublishVariableHeader mqttPublishVariableHeader=new MqttPublishVariableHeader("down/light/ack/40005274",0);
		JSONObject jsonObject = new JSONObject();
		jsonObject.put("flag","1");
		jsonObject.put("cmd","1111");
		byte[] bytes = jsonObject.toString().getBytes();
		ByteBuf byteBuf = Unpooled.wrappedBuffer(bytes);
		//推送消息体
		MqttPublishMessage mqttPublishMessageResult=new MqttPublishMessage(FixedHeader,mqttPublishVariableHeader, byteBuf);
		log.info("推送地址————》"+mqttPublishVariableHeader);
				//订阅次此topic的Mqtt客户端搜到此消息，
				Channel channelSub= MQTTServer.MQTTdeviceChannelGroup.find(channel.id());
				//writeAndFlush会将ByteBuf的引用释放，refCnt会减去1,使用retain加1
				if(channelSub!=null) {
					mqttPublishMessageResult.retain();
					channelSub.writeAndFlush(mqttPublishMessageResult);
					System.out.println("channelSub="+channelSub+"-----------mqttPublishMessageResult="+mqttPublishMessageResult);
				}
			mqttPublishMessageResult.release();
	}

	/**
	 * 用户鉴权
	 */
	public boolean authentication(MqttConnectPayload payload){
		//todo 这里只是使用了最直接的账号密码鉴权，这里可以进行diy，
		// 例如客户端用sha256算法加密（设备名（username）+系统时间戳+设备密钥（password）)得到加密密钥
		// 服务器根据设备名和设备密钥再进行同样的操作，再比较服务端和客户端加密的密钥是否一致
		// 加密算法放下面了
		log.warn("clientId"+payload.clientIdentifier());
		String username=MQTTserverProperties.getUsername();
		String password=MQTTserverProperties.getPassword();
		//无账号或者无密码通过
		if(stringEmptyCheck(password)||stringEmptyCheck(username)){
			return true;
		}else {
			//消息中账号密码为空
			if(payload.passwordInBytes()==null||payload.userName()==null){
				return false;
			}
			String passwordAuthen=new String(payload.passwordInBytes());
			String usernameAuthen=payload.userName();
			log.warn("username:{},password:{}",usernameAuthen,passwordAuthen);
			if(password.equals(passwordAuthen)&&username.equals(usernameAuthen)){
				return true;
			}else {
				return false;
			}
		}
	}
	/**
	 * sha256_HMAC加密
	 * @param message 设备名+时间戳
	 * @param secret  设备秘钥
	 * @return 加密密钥字符串
	 */
	public String hmacSHA256(String secret, String message) throws Exception {
		String hash = "";
		Mac hmacSha256 = Mac.getInstance("HmacSHA256");
		SecretKeySpec secret_key = new SecretKeySpec(secret.getBytes(), "HmacSHA256");
		hmacSha256.init(secret_key);
		byte[] bytes = hmacSha256.doFinal(message.getBytes());
		hash = byteArrayToHexString(bytes);
		return hash;
	}
	/**
	 * 将加密后的字节数组转换成字符串
	 *
	 * @param b 字节数组
	 * @return 字符串
	 */
	public  String byteArrayToHexString(byte[] b) {
		StringBuilder hs = new StringBuilder();
		String stmp;
		for (int n = 0; b!=null && n < b.length; n++) {
			stmp = Integer.toHexString(b[n] & 0XFF);
			if (stmp.length() == 1)
				hs.append('0');
			hs.append(stmp);
		}
		return hs.toString().toLowerCase();
	}

	//判断字符字符为空
	private boolean stringEmptyCheck(String str){
		if(str==null||"".equals(str)){
			return true;
		}else {
			return false;
		}
	}

}