package mqtt_client

import (
	"encoding/json"
	"errors"
	"git.sxidc.com/go-tools/utils/strutils"
	mqtt "github.com/eclipse/paho.mqtt.golang"
	"log"
	"sync"
	"time"
)

var (
	ErrMessageIgnore = errors.New("mqtt消息忽略")
)

type MessageHandler func(client *Client, token *SubscribeToken, topic string, data []byte) error

type ClientOptions struct {
	UserName        string
	Password        string
	Address         string
	ClientID        string
	KeepAliveSec    int64
	PingTimeoutSec  int64
	WriteTimeoutSec int64
}

func (opts *ClientOptions) check() error {
	if strutils.IsStringEmpty(opts.UserName) {
		return errors.New("必须传递用户名")
	}

	if strutils.IsStringEmpty(opts.Password) {
		return errors.New("必须传递密码")
	}

	if strutils.IsStringEmpty(opts.Address) {
		return errors.New("必须传递地址")
	}

	if strutils.IsStringEmpty(opts.ClientID) {
		return errors.New("必须传递客户端ID")
	}

	return nil
}

type SubscribeToken struct {
	messageHandler     MessageHandler
	successHandleCount int
	handleCount        int
}

func (token *SubscribeToken) SuccessHandleCount() int {
	return token.successHandleCount
}

func (token *SubscribeToken) HandleCount() int {
	return token.handleCount
}

type subscribeTopic struct {
	topic  string
	tokens []*SubscribeToken
}

type Client struct {
	client mqtt.Client
	opts   *ClientOptions

	topicsMutex *sync.Mutex
	topics      []*subscribeTopic

	publishAndReceiveTopicMapMutex sync.Mutex
	publishAndReceiveTopicMap      map[string]chan any
}

func New(opts *ClientOptions) (*Client, error) {
	if opts == nil {
		return nil, errors.New("必须传递参数")
	}

	err := opts.check()
	if err != nil {
		return nil, err
	}

	if opts.WriteTimeoutSec == 0 {
		opts.WriteTimeoutSec = 60
	}

	client := &Client{
		opts:                      opts,
		topicsMutex:               &sync.Mutex{},
		topics:                    make([]*subscribeTopic, 0),
		publishAndReceiveTopicMap: make(map[string]chan any),
	}

	mqttClient := mqtt.NewClient(mqtt.NewClientOptions().
		SetAutoReconnect(true).
		SetUsername(opts.UserName).
		SetPassword(opts.Password).
		AddBroker(opts.Address).
		SetClientID(opts.ClientID).
		SetKeepAlive(time.Duration(opts.KeepAliveSec)*time.Second).
		SetPingTimeout(time.Duration(opts.PingTimeoutSec)*time.Second).
		SetWriteTimeout(time.Duration(opts.WriteTimeoutSec)*time.Second).
		SetOrderMatters(false).
		SetWill(opts.ClientID+"/will", "dead", 2, true).
		SetOnConnectHandler(func(mqttClient mqtt.Client) {
			err := client.subscribeAll()
			if err != nil {
				log.Println("SetOnConnectHandler:", err.Error())
				return
			}
		}))

	token := mqttClient.Connect()
	if !token.WaitTimeout(time.Duration(opts.WriteTimeoutSec) * time.Second) {
		return nil, errors.New("连接超时")
	}

	if token.Error() != nil {
		return nil, token.Error()
	}

	client.client = mqttClient

	return client, nil
}

func Destroy(client *Client) {
	client.client.Disconnect(250)
	client.topicsMutex.Lock()

	for _, subscribedTopic := range client.topics {
		token := client.client.Unsubscribe(subscribedTopic.topic)
		if !token.WaitTimeout(time.Duration(client.opts.WriteTimeoutSec) * time.Second) {
			continue
		}

		if token.Error() != nil {
			log.Println("Destroy: ", token.Error())
			continue
		}
	}

	client.topics = nil

	client.topicsMutex.Unlock()

	client = nil
}

func (client *Client) Publish(topic string, qos byte, retained bool, payload any) error {
	if strutils.IsStringEmpty(topic) {
		return errors.New("没有传递发布主题")
	}

	if payload == nil {
		return errors.New("发布的payload不能为nil")
	}

	client.publish(topic, qos, retained, payload)

	return nil
}

func (client *Client) Subscribe(topic string, handlerFunc MessageHandler) (*SubscribeToken, error) {
	if strutils.IsStringEmpty(topic) {
		return nil, errors.New("没有传递订阅主题")
	}

	if handlerFunc == nil {
		return nil, errors.New("必须传递处理函数")
	}

	return client.subscribe(topic, handlerFunc)
}

func (client *Client) Unsubscribe(topic string, token *SubscribeToken) error {
	if strutils.IsStringEmpty(topic) {
		return errors.New("没有传递取消订阅主题")
	}

	return client.unsubscribe(topic, token)
}

type PublishAndReceiveReplyParams struct {
	Topic                string
	ReplyTopic           string
	PublishData          []byte
	RepublishDurationSec int64
	TryTimes             int
	StopBefore           bool
}

func (params *PublishAndReceiveReplyParams) Check() error {
	if strutils.IsStringEmpty(params.Topic) {
		return errors.New("没有传递订阅主题")
	}

	if strutils.IsStringEmpty(params.ReplyTopic) {
		return errors.New("没有传递响应订阅主题")
	}

	if params.PublishData == nil {
		return errors.New("发布的数据不能为nil")
	}

	return nil
}

type msgResponse struct {
	Success bool   `json:"success"`
	Msg     string `json:"msg"`
}

func (client *Client) PublishAndReceiveReplyMsgResponse(params *PublishAndReceiveReplyParams) error {
	err := params.Check()
	if err != nil {
		return err
	}

	err = client.publishAndReceiveReply(params, func(payload []byte) error {
		resp := new(msgResponse)
		err := json.Unmarshal(payload, resp)
		if err != nil {
			return err
		}

		if !resp.Success {
			return errors.New(resp.Msg)
		}

		return nil
	})
	if err != nil {
		return err
	}

	return nil
}

func (client *Client) PublishAndReceiveReply(params *PublishAndReceiveReplyParams, payloadDealFunc func(payload []byte) error) error {
	err := params.Check()
	if err != nil {
		return err
	}

	return client.publishAndReceiveReply(params, payloadDealFunc)
}

func (client *Client) publish(topic string, qos byte, retained bool, payload any) {
	client.waitConnected()

	token := client.client.Publish(topic, qos, retained, payload)
	if !token.WaitTimeout(time.Duration(client.opts.WriteTimeoutSec) * time.Second) {
		log.Println("发布超时")
		return
	}

	if token.Error() != nil {
		log.Println("publish:", token.Error())
		return
	}
}

func (client *Client) subscribe(topic string, handlerFunc MessageHandler) (*SubscribeToken, error) {
	client.waitConnected()

	return client.addSubscribedTopic(topic, handlerFunc, func(subscribedTopic *subscribeTopic) error {
		return client.doSubscribe(subscribedTopic)
	})
}

func (client *Client) unsubscribe(topic string, token *SubscribeToken) error {
	client.waitConnected()

	err := client.removeSubscribedTopic(topic, token, func(subscribedTopic *subscribeTopic) error {
		token := client.client.Unsubscribe(subscribedTopic.topic)
		if !token.WaitTimeout(time.Duration(client.opts.WriteTimeoutSec) * time.Second) {
			return errors.New("取消订阅超时")
		}

		if token.Error() != nil {
			return token.Error()
		}

		return nil
	})
	if err != nil {
		return err
	}

	return nil
}

func (client *Client) publishAndReceiveReply(params *PublishAndReceiveReplyParams, payloadDealFunc func(payload []byte) error) error {
	doneChan := make(chan any)

	if params.StopBefore {
		client.publishAndReceiveTopicMapMutex.Lock()
		existDoneChan, ok := client.publishAndReceiveTopicMap[params.Topic]
		if ok {
			close(existDoneChan)
			delete(client.publishAndReceiveTopicMap, params.Topic)
		} else {
			client.publishAndReceiveTopicMap[params.Topic] = doneChan
		}
		client.publishAndReceiveTopicMapMutex.Unlock()
	}

	// 订阅响应主题
	token, err := client.subscribe(params.ReplyTopic, func(c *Client, token *SubscribeToken, topic string, data []byte) error {
		defer func() {
			client.publishAndReceiveTopicMapMutex.Lock()
			existDoneChan, ok := client.publishAndReceiveTopicMap[params.Topic]
			if ok {
				close(existDoneChan)
				delete(client.publishAndReceiveTopicMap, params.Topic)
			}
			client.publishAndReceiveTopicMapMutex.Unlock()
		}()

		if token.SuccessHandleCount() >= 1 {
			return ErrMessageIgnore
		}

		if payloadDealFunc != nil {
			err := payloadDealFunc(data)
			if err != nil {
				return err
			}
		}

		return nil
	})
	if err != nil {
		return err
	}

	go func() {
		client.publish(params.Topic, 2, false, params.PublishData)

		currentTryTime := 1
		timer := time.NewTimer(time.Duration(params.RepublishDurationSec) * time.Second)
		defer timer.Stop()

		for {
			select {
			case <-doneChan:
				err := client.unsubscribe(params.ReplyTopic, token)
				if err != nil {
					log.Println("publishAndReceiveReply done:", err.Error())
					return
				}

				client.publishAndReceiveTopicMapMutex.Lock()
				delete(client.publishAndReceiveTopicMap, params.Topic)
				client.publishAndReceiveTopicMapMutex.Unlock()

				return
			case <-timer.C:
				client.publish(params.Topic, 2, false, params.PublishData)

				if params.TryTimes != 0 {
					currentTryTime++
				}

				if params.TryTimes != 0 && currentTryTime > params.TryTimes {
					client.publishAndReceiveTopicMapMutex.Lock()
					existDoneChan, ok := client.publishAndReceiveTopicMap[params.Topic]
					if ok {
						close(existDoneChan)
						delete(client.publishAndReceiveTopicMap, params.Topic)
					}
					client.publishAndReceiveTopicMapMutex.Unlock()
					return
				}

				resetDuration := time.Duration(params.RepublishDurationSec*int64(currentTryTime)) * time.Second
				timer.Reset(resetDuration)
			}
		}
	}()

	return nil
}

func (client *Client) waitConnected() {
	for {
		if client.client.IsConnected() {
			break
		}

		time.Sleep(1 * time.Second)
	}
}

func (client *Client) subscribeAll() error {
	err := client.rangeSubscribedTopics(func(subscribedTopic *subscribeTopic) error {
		return client.doSubscribe(subscribedTopic)
	})
	if err != nil {
		return err
	}

	return nil
}

func (client *Client) doSubscribe(subscribedTopic *subscribeTopic) error {
	token := client.client.Subscribe(subscribedTopic.topic, 2, func(mqttClient mqtt.Client, message mqtt.Message) {
		wg := sync.WaitGroup{}
		wg.Add(len(subscribedTopic.tokens))
		for _, token := range subscribedTopic.tokens {
			go func(token *SubscribeToken, message mqtt.Message) {
				defer func() {
					token.handleCount++
					wg.Done()
				}()

				err := token.messageHandler(client, token, subscribedTopic.topic, message.Payload())
				if err != nil && !errors.Is(err, ErrMessageIgnore) {
					log.Println("doSubscribe token.messageHandler:", err.Error())
					return
				}

				if err != nil && errors.Is(err, ErrMessageIgnore) {
					return
				}

				token.successHandleCount++
			}(token, message)
		}
		wg.Wait()
	})
	if !token.WaitTimeout(time.Duration(client.opts.WriteTimeoutSec) * time.Second) {
		return errors.New("订阅超时")
	}

	if token.Error() != nil {
		return token.Error()
	}

	return nil
}

func (client *Client) addSubscribedTopic(topic string, handler MessageHandler, addNew func(subscribedTopic *subscribeTopic) error) (*SubscribeToken, error) {
	client.topicsMutex.Lock()
	defer client.topicsMutex.Unlock()

	newToken := &SubscribeToken{messageHandler: handler}

	for _, savedTopic := range client.topics {
		if savedTopic.topic == topic {
			savedTopic.tokens = append(savedTopic.tokens, newToken)
			return newToken, nil
		}
	}

	subscribedTopic := &subscribeTopic{
		topic:  topic,
		tokens: []*SubscribeToken{newToken},
	}

	err := addNew(subscribedTopic)
	if err != nil {
		return nil, err
	}

	client.topics = append(client.topics, subscribedTopic)
	return newToken, nil
}

func (client *Client) removeSubscribedTopic(topic string, token *SubscribeToken, noTokens func(subscribedTopic *subscribeTopic) error) error {
	client.topicsMutex.Lock()
	defer client.topicsMutex.Unlock()

	findSubscribeTopicIndex := -1
	for index, subscribedTopic := range client.topics {
		if subscribedTopic.topic == topic {
			findSubscribeTopicIndex = index
		}
	}

	if findSubscribeTopicIndex == -1 {
		return nil
	}

	subscribedTopic := client.topics[findSubscribeTopicIndex]
	if subscribedTopic.tokens != nil && len(subscribedTopic.tokens) == 1 {
		err := noTokens(subscribedTopic)
		if err != nil {
			return err
		}

		client.topics = append(client.topics[:findSubscribeTopicIndex], client.topics[findSubscribeTopicIndex+1:]...)
		return nil
	}

	findTokenIndex := -1
	for index, savedToken := range subscribedTopic.tokens {
		if savedToken == token {
			findTokenIndex = index
		}
	}

	if findTokenIndex == -1 {
		return nil
	}

	subscribedTopic.tokens = append(subscribedTopic.tokens[:findTokenIndex], subscribedTopic.tokens[findTokenIndex+1:]...)
	return nil
}

func (client *Client) rangeSubscribedTopics(rangeFunc func(subscribedTopic *subscribeTopic) error) error {
	client.topicsMutex.Lock()
	defer client.topicsMutex.Unlock()

	for _, subscribedTopic := range client.topics {
		tempTopic := subscribedTopic
		err := rangeFunc(tempTopic)
		if err != nil {
			return err
		}
	}

	return nil
}