package mqtt_api

import (
	"git.sxidc.com/go-framework/baize/framework/core/infrastructure/logger"
	"sync"
)

type Handler func(c *Context)

type subscribeItem struct {
	handlers   []Handler
	subscribed bool
}

type Router struct {
	Group string

	mqttClient *MqttClient

	contextsMutex *sync.Mutex
	contexts      []*Context

	globalHandlers []Handler

	subscribeItemsMutex *sync.Mutex
	subscribeItems      map[string]*subscribeItem
}

func NewRouter(group string, globalHandlers []Handler) *Router {
	return &Router{
		Group:               group,
		mqttClient:          nil,
		contextsMutex:       &sync.Mutex{},
		contexts:            make([]*Context, 0),
		globalHandlers:      globalHandlers,
		subscribeItemsMutex: &sync.Mutex{},
		subscribeItems:      make(map[string]*subscribeItem),
	}
}

func DestroyRouter(router *Router) {
	if router == nil {
		return
	}

	router.contextsMutex.Lock()

	for _, context := range router.contexts {
		destroyContext(context)
	}

	router.contexts = nil

	router.contextsMutex.Unlock()

	router = nil
}

func (router *Router) Start(mqttOptions *MqttClientOptions) error {
	mqttClient, err := newMqttClient(mqttOptions, func(client *MqttClient) {
		router.subscribeTopics(client)
	}, func(client *MqttClient) {
		router.unsubscribeTopics(client)
	})
	if err != nil {
		return err
	}

	err = mqttClient.connect()
	if err != nil {
		return err
	}

	router.mqttClient = mqttClient

	return nil
}

func (router *Router) Finish() {
	if router.mqttClient == nil {
		return
	}

	router.unsubscribeTopics(router.mqttClient)

	router.mqttClient.disconnect()
	destroyMqttClient(router.mqttClient)
	router.mqttClient = nil
}

func (router *Router) AddGlobalHandlers(handlers ...Handler) {
	router.globalHandlers = append(router.globalHandlers, handlers...)
}

func (router *Router) AddTopic(topic string, handlers ...Handler) error {
	allHandlers := append(router.globalHandlers, handlers...)
	err := router.addAndSubscribeTopicHandlers(router.Group+topic, allHandlers...)
	if err != nil {
		return err
	}

	return nil
}

func (router *Router) subscribeTopics(client *MqttClient) {
	if !client.mqttClient.IsConnected() {
		return
	}

	router.rangeTopicHandlers(func(topic string, handlers []Handler) {
		err := router.subscribeMqttClient(client, topic, handlers)
		if err != nil {
			logger.GetInstance().Error(err)
			return
		}
	})
}

func (router *Router) unsubscribeTopics(client *MqttClient) {
	if !client.mqttClient.IsConnected() {
		return
	}

	router.rangeTopicHandlers(func(topic string, handlers []Handler) {
		err := client.unsubscribe(topic)
		if err != nil {
			logger.GetInstance().Error(err)
			return
		}
	})
}

func (router *Router) subscribeMqttClient(client *MqttClient, topic string, handlers []Handler) error {
	err := client.subscribe(topic, func(topic string, data []byte) {
		c, err := newContext(router.mqttClient, topic, data, handlers)
		if err != nil {
			logger.GetInstance().Error(err)
			return
		}

		c.callHandlers()

		c.Next()
	})
	if err != nil {
		return err
	}

	return nil
}

func (router *Router) addAndSubscribeTopicHandlers(topic string, handlers ...Handler) error {
	router.subscribeItemsMutex.Lock()
	defer router.subscribeItemsMutex.Unlock()

	router.subscribeItems[topic] = &subscribeItem{
		handlers:   handlers,
		subscribed: false,
	}

	if router.mqttClient == nil {
		return nil
	}

	if !router.mqttClient.mqttClient.IsConnected() {
		return nil
	}

	err := router.subscribeMqttClient(router.mqttClient, topic, handlers)
	if err != nil {
		return err
	}

	router.subscribeItems[topic].subscribed = true

	return nil
}

func (router *Router) removeTopicHandlers(topic string) {
	router.subscribeItemsMutex.Lock()
	defer router.subscribeItemsMutex.Unlock()

	if router.subscribeItems[topic] == nil {
		return
	}

	delete(router.subscribeItems, topic)
}

func (router *Router) rangeTopicHandlers(callback func(topic string, handlers []Handler)) {
	router.subscribeItemsMutex.Lock()
	defer router.subscribeItemsMutex.Unlock()

	for topic, item := range router.subscribeItems {
		if !item.subscribed {
			callback(topic, item.handlers)
		}
	}
}