package backend

import (
	"crypto/tls"
	"crypto/x509"
	"fmt"
	"strings"
	"time"

	"agent/cmd/agent/config"
	"agent/cmd/agent/global"
	"agent/cmd/agent/option"
	"linkfog.com/public/lib/l"

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

type Backend struct {
	isRunning      bool
	client         MQTT.Client
	ReconnectTimes int
	Status         int
	signal         chan struct{}
}

type BackendOpt func(*Backend)

var backendMod *Backend

func New(opts ...BackendOpt) *Backend {
	b := Backend{
		signal: make(chan struct{}),
	}
	for _, opt := range opts {
		opt(&b)
	}

	clientOpts := MQTT.NewClientOptions()
	for _, b := range global.HostInfoTail.MQTTInfo.BrokerInfo {
		clientOpts.AddBroker(fmt.Sprintf("ssl://%s", b.IP))
	}

	// NOTE: 自测使用
	if config.Edition == "dev" {
		clientOpts.AddBroker(fmt.Sprintf("%s:%d", option.Opt.MQTTBrokerURL, option.Opt.MQTTBrokerPort))
	}
	clientOpts.SetClientID(global.DeviceSerialNumber)
	clientOpts.SetUsername(global.MQTTUsername)
	clientOpts.SetPassword(global.MQTTPassword)

	// TLS配置
	tlsConfig, err := newTlsConfig()
	if err != nil {
		l.Error(err)
		return nil
	}
	clientOpts.SetTLSConfig(tlsConfig)

	// 设置session持久化订阅，基于clientid，在客户端断开连接时topic不会自动删除
	clientOpts.SetCleanSession(false)

	// 设置自动重连
	clientOpts.SetAutoReconnect(true)
	clientOpts.SetMaxReconnectInterval(10 * time.Second)

	// 设置回调函数
	clientOpts.SetOnConnectHandler(connectCallback)
	clientOpts.SetConnectionLostHandler(connectInterruptionCallback)
	clientOpts.SetReconnectingHandler(reconnectingCallback)
	clientOpts.SetDefaultPublishHandler(handleSubscribeMsgCallback)

	// 初始化客户端
	b.client = MQTT.NewClient(clientOpts)

	backendMod = &b
	return &b
}

func (b *Backend) Start() error {
	b.isRunning = true

	for {
		if token := b.client.Connect(); token.Wait() && token.Error() != nil {
			l.Warnf("MQTT init connecting err :%v", token.Error())
			b.Status = global.MQTTFailedToConnect
			b.ReconnectTimes++
		} else {
			l.Info("MQTT init connecting success")
			b.Status = global.MQTTConnected
			break
		}

		time.Sleep(2 * time.Minute)
	}

	go func() {
		for {
			select {
			case msg := <-global.HostInfoTail.MQTTInfo.PublishChan:
				topic := translateTopic(msg.Key)
				if len(topic) > 0 {
					b.client.Publish(topic, 1, false, []byte(msg.Payload))
				}
			case <-b.signal:
				l.Info("MQTT exit")
				return
			}
		}
	}()
	return nil
}

func (b *Backend) Stop() {
	if b.IsRunning() {
		b.isRunning = false
		b.signal <- struct{}{}
		b.client.Disconnect(250)

	}
}

func (b *Backend) Name() string { return global.BackendModuleName }

func (b *Backend) IsRunning() bool {
	return b.isRunning
}

func connectCallback(client MQTT.Client) {
	l.Info("MQTT connected")
	backendMod.Status = global.MQTTConnected
	// 订阅
	if token := client.Subscribe(global.DeviceSerialNumber+"/publish/#", 1, nil); token.Wait() && token.Error() != nil {
		l.Error(token.Error())
	}
	//if token := client.Subscribe("device/sleep", 1, nil); token.Wait() && token.Error() != nil {
	//	l.Error(token.Error())
	//}
}

func connectInterruptionCallback(client MQTT.Client, err error) {
	l.Infof("MQTT connection interruption err:%s", err)
	backendMod.Status = global.MQTTReConnecting
}

func reconnectingCallback(client MQTT.Client, opts *MQTT.ClientOptions) {
	l.Info("MQTT reconnecting")
	backendMod.ReconnectTimes++
}

func handleSubscribeMsgCallback(client MQTT.Client, msg MQTT.Message) {
	l.Infof("MQTT Received message from topic %s, %s", msg.Topic(), string(msg.Payload()))
	if strings.HasPrefix(msg.Topic(), global.SubscribePrefixInfo) {
		key := msg.Topic()[strings.Index(msg.Topic(), global.SubscribePrefixInfo)+len(global.SubscribePrefixInfo):]
		global.HostInfoTail.MQTTInfo.ConsumeChan <- &global.Message{
			Payload: string(msg.Payload()),
			Key:     key,
		}
	}
	//} else if msg.Topic() == "device/sleep" {
	//	mp := make(map[string]interface{})
	//	err := json.Unmarshal(msg.Payload(), &mp)
	//	if err != nil {
	//		l.Errorf("MQTT fail to json Unmarshal, err:%v", err)
	//		return
	//	}
	//	if tmp, ok := mp["sleep"].(string); ok {
	//		s, _ := strconv.Atoi(tmp)
	//		time.Sleep(time.Duration(s) * time.Second)
	//	}
	//	mp["sn"] = global.DeviceSerialNumber
	//	data, _ := json.Marshal(mp)
	//	client.Publish("device/awake", 1, false, data)
	//}
}

func translateTopic(key string) (ret string) {
	if l := strings.Index(key, "agent."); l != -1 && l < len(key) {
		ret = strings.Replace(key[l:], ".", "_", -1)
	}

	return ret
}

func (b *Backend) Receive(msg *global.Message) error {
	return nil
}

func newTlsConfig() (*tls.Config, error) {
	// 配置 TLS 以忽略证书验证
	cfg := new(tls.Config)
	cfg.RootCAs = x509.NewCertPool()

	certPemBytes, err := global.CertFS.ReadFile(global.MyCertPem)
	if err != nil {
		return nil, fmt.Errorf("load cert pem err:%s", err)
	}

	certKeyBytes, err := global.CertFS.ReadFile(global.MyCertKey)
	if err != nil {
		return nil, fmt.Errorf("load key pem err:%s", err)
	}

	cert, err := tls.X509KeyPair(certPemBytes, certKeyBytes)
	if err != nil {
		return nil, fmt.Errorf("parse cert/key err:%s", err)
	}

	cfg.Certificates = append(cfg.Certificates, cert)

	cfg.InsecureSkipVerify = true

	return cfg, nil
}