package mqtt

import (
	"fmt"
	"log/slog"
	"math/rand"
	"time"

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

// MQTT客户端连接配置
type MqttOptions struct {
	// MQTT Broker 代理
	Broker string
	// 认证用户名
	Username string
	// 认证密码
	Password string
}

func NewMqttOptions(address, username, password string) MqttOptions {
	return MqttOptions{
		Broker:   address,
		Username: username,
		Password: password,
	}
}

var messagePubHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
	slog.Debug("MQTT收到消息", "topic", msg.Topic(), "msg", string(msg.Payload()))
}

var connectHandler mqtt.OnConnectHandler = func(client mqtt.Client) {
	or := client.OptionsReader()
	slog.Info("MQTT连接成功", "ClientID", or.ClientID())
	// subs := make(map[string]byte)
	// subs["$SYS/brokers/+/clients/+/+"] = 0
	// client.SubscribeMultiple(subs, messagePubHandler)
}

var connectLostHandler mqtt.ConnectionLostHandler = func(client mqtt.Client, err error) {
	slog.Error("MQTT连接断开", "error", err)
}

var mqttClient mqtt.Client
var clientId string

// 初始化MQTT客户端id
func initClientId() {
	if clientId == "" {
		us := uuid.New().String()
		usl := len(us)
		sufix5 := us[usl-5 : usl]
		clientId = fmt.Sprintf("%s%d", sufix5, rand.New(rand.NewSource(time.Now().UnixNano())).Int()%1000)
	}
}

// 获取MQTT客户端id
func GetClientId() string {
	return clientId
}

// 启动MQTT
func Startup(options MqttOptions) {
	initClientId()
	opts := mqtt.NewClientOptions()
	opts.AddBroker(options.Broker)
	opts.SetClientID(clientId)
	opts.SetUsername(options.Username)
	opts.SetPassword(options.Password)
	opts.SetDefaultPublishHandler(messagePubHandler)
	opts.OnConnect = connectHandler
	opts.OnConnectionLost = connectLostHandler
	client := mqtt.NewClient(opts)
	if token := client.Connect(); token.Wait() && token.Error() != nil {
		panic(token.Error())
	}
	mqttClient = client
}

// 发布消息
func Publish(dest string, data any) error {
	token := mqttClient.Publish(dest, 0, false, data)
	if token.Wait() && token.Error() != nil {
		return token.Error()
	}
	return nil
}