package mqtt

import (
	"fmt"
	"log"

	mqtt "github.com/eclipse/paho.mqtt.golang"
)

type MqttClient struct {
	Client        mqtt.Client
	SubscribeList []SubscribeConf
}

type MqttConf struct {
	Host     string
	Port     string
	Username string
	Password string
	ClientId string
}

type SubscribeConf struct {
	Topic   string
	Handler func(mqtt.Client, mqtt.Message)
}

func NewMqttClient() *MqttClient {
	c := &MqttClient{}
	c.Client = nil
	c.SubscribeList = make([]SubscribeConf, 0)

	return c
}

func (c *MqttClient) SubTopic(topic string, f func(mqtt.Client, mqtt.Message)) {
	c.SubscribeList = append(c.SubscribeList, SubscribeConf{
		Topic:   topic,
		Handler: f,
	})
}

func (c *MqttClient) Connect(conf MqttConf) {
	host := conf.Host
	port := conf.Port
	username := conf.Username
	password := conf.Password
	clientId := conf.ClientId

	opts := mqtt.NewClientOptions()
	opts.AddBroker(fmt.Sprintf("tcp://%s:%s", host, port))
	opts.SetAutoReconnect(true) // 自动重连
	opts.SetUsername(username)
	opts.SetPassword(password)
	opts.SetClientID(clientId)

	opts.SetOnConnectHandler(func(client mqtt.Client) {
		log.Println("mqtt 连接成功")

		// 创建订阅
		log.Println("加载订阅...")
		c.CreateSubscribe()
		log.Println("加载订阅完成")
	})

	opts.SetConnectionLostHandler(func(client mqtt.Client, err error) {
		log.Println("mqtt 连接断开")
	})

	client := mqtt.NewClient(opts)

	if token := client.Connect(); token.Wait() && token.Error() != nil {
		panic("创建mqtt客户端错误,错误信息: " + token.Error().Error())
	}

	c.Client = client
}

func (c *MqttClient) Publish(topic string, payload []byte) {
	token := c.Client.Publish(topic, 0, false, payload)
	token.Wait()
}

func (c *MqttClient) CreateSubscribe() {
	for _, conf := range c.SubscribeList {
		if token := c.Client.Subscribe(conf.Topic, 1, conf.Handler); token.Wait() && token.Error() != nil {
			log.Fatal(token.Error())
		}
		log.Printf("订阅 %s 完成\n", conf.Topic)
	}
}