package MqttService

import (
	"crypto/tls"
	mqtt "github.com/eclipse/paho.mqtt.golang"
	log "github.com/sirupsen/logrus"
	"net/url"
	"rpiMqttControl/internal/PinControlService"
	"time"
)

type OnCompletionHandler func()

type MqttService struct {
	mqttClient mqtt.Client
	quit       chan struct{}
	config     MqttServiceConfig
	pinService *PinControlService.PinControlService
}

func (m *MqttService) pinEventCallback(pinName string, pinState PinControlService.PinState) {
	topic := m.config.TopicPrefix + "/gpio/" + pinName + "/event"
	token := m.mqttClient.Publish(topic, 1, false, string(pinState))
	go m._asyncWait(token, nil)
}

func (m *MqttService) pinCyclicCallback(pinName string, pinState PinControlService.PinState) {
	topic := m.config.TopicPrefix + "/gpio/" + pinName + "/value"
	token := m.mqttClient.Publish(topic, 1, false, string(pinState))
	go m._asyncWait(token, nil)
}
func (m *MqttService) controlCallback(_ mqtt.Client, message mqtt.Message) {
	if pinNo, err := PinNameFromTopic(message.Topic()); err == nil {
		if err := m.pinService.Command(pinNo, PinControlService.PinCommand(message.Payload())); err != nil {
			log.Error(err.Error())
		}
	} else {
		log.Error(err.Error())
	}
}
func (m *MqttService) Stop() {
	m.quit <- struct{}{}
	m.mqttClient.Disconnect(100)
}

func (m *MqttService) _asyncWait(token mqtt.Token, onComplete OnCompletionHandler) {
	for {
		select {
		case <-token.Done():
			if err := token.Error(); err != nil {
				log.Fatal(err)
			} else {
				if onComplete != nil {
					onComplete()
				}
			}
			return
		case <-m.quit:
			return
		}
	}
}
func (m *MqttService) _subscribe() {
	topic := m.config.TopicPrefix + "/gpio/+/control"
	token := m.mqttClient.Subscribe(topic, 1, m.controlCallback)

	go m._asyncWait(token, nil)
}

func (m *MqttService) Start() {
	m.mqttClient.Connect()
}

func NewMqttService(config MqttServiceConfig, pinService *PinControlService.PinControlService) MqttService {
	clientOptions := mqtt.NewClientOptions()
	clientOptions.AddBroker(config.BrokerAddress)

	if config.Username != "" {
		clientOptions.Username = config.Username
		clientOptions.Password = config.Password
	}

	clientOptions.SetConnectRetry(true)
	clientOptions.SetConnectRetryInterval(time.Duration(config.ConnectRetryIntervalMs) * time.Millisecond)
	clientOptions.SetMaxReconnectInterval(time.Duration(config.MaxReconnectIntervalMs) * time.Millisecond)
	clientOptions.SetAutoReconnect(config.AutoReconnect)
	clientOptions.SetConnectTimeout(time.Duration(config.ConnectTimeoutMs) * time.Millisecond)
	clientOptions.SetConnectionLostHandler(func(client mqtt.Client, err error) {
		log.Warn("connection lost to broker")
	})

	clientOptions.SetConnectionAttemptHandler(func(broker *url.URL, tlsCfg *tls.Config) *tls.Config {
		log.Infof("connection attempt to %s", broker.String())
		return tlsCfg
	})
	var mqttService *MqttService
	clientOptions.SetOnConnectHandler(func(client mqtt.Client) {
		log.Info("successfully connected to broker")
		mqttService._subscribe()
	})
	mqttClient := mqtt.NewClient(clientOptions)

	m := MqttService{
		mqttClient: mqttClient,
		quit:       make(chan struct{}, 1),
		pinService: pinService,
		config:     config,
	}
	mqttService = &m

	pinService.OnCycleCallback = m.pinCyclicCallback
	pinService.OnChangeCallback = m.pinEventCallback

	return m
}