package worker

import (
	"encoding/json"
	"errors"
	"fmt"
	orglog "log"
	"os"
	"strconv"
	"strings"
	"time"

	mqtt "github.com/eclipse/paho.mqtt.golang"
	"wkla.no-ip.biz/gogs/Willie/MsgService/MessageService/model"
)

const processorPrefix = "processor"
const datasourcePrefix = "datasource"

func CreateMQTTDestinationProcessor(backend string, destination model.Destination) (DestinationProcessor, error) {
	processor := MQTTDestinationProcessor{
		Backend:     backend,
		Destination: destination,
	}
	return &processor, nil
}

//MQTTDestinationProcessor does nothing
type MQTTDestinationProcessor struct {
	Backend     string
	Destination model.Destination
}

//Initialise the mqtt processor
func (m *MQTTDestinationProcessor) Initialise(backend string, destination model.Destination) error {
	// delete an already connected mqtt processor
	//	if m.Destination != nil {
	datasinkNsName := GetMQTTClientNsName(processorPrefix, backend, m.Destination.Name)
	datasink, ok := mqttClients[datasinkNsName]
	if ok {
		if datasink.Client != nil {
			datasink.Client.Disconnect(1000)
		}
	}
	delete(mqttClients, datasinkNsName)
	//	}
	m.Destination = destination
	// now initilaise the new connection
	datasink, err := getDatasinkMQTTClient(datasinkNsName, backend, destination.Config.(model.DataSourceConfigMQTT))
	if err != nil {
		log.Alertf("%v", err)
		return err
	}
	return nil
}

//Destroy the mqtt processor
func (m *MQTTDestinationProcessor) Destroy(backend string, destination model.Destination) error {
	datasinkNsName := GetMQTTClientNsName(processorPrefix, backend, m.Destination.Name)
	datasink, ok := mqttClients[datasinkNsName]
	if ok {
		if datasink.Client != nil {
			datasink.Client.Disconnect(1000)
		}
		delete(mqttClients, datasinkNsName)
	}
	return nil
}

//Store stores the message to a topic
func (m *MQTTDestinationProcessor) Store(data model.JSONMap) (string, error) {
	datasinkNsName := GetMQTTClientNsName(processorPrefix, m.Backend, m.Destination.Name)
	datasink, ok := mqttClients[datasinkNsName]
	if !ok {
		err := m.Initialise(m.Backend, m.Destination)
		if err != nil {
			return "", err
		}
		datasinkNsName = GetMQTTClientNsName(processorPrefix, m.Backend, m.Destination.Name)
		datasink, ok = mqttClients[datasinkNsName]
		if !ok {
			return "", errors.New("destination client is not ready")
		}
	}
	payload, err := json.Marshal(data)
	if err != nil {
		return "", err
	}
	config := m.Destination.Config.(model.DataSourceConfigMQTT)
	token := datasink.Client.Publish(datasink.Topic, byte(config.QoS), false, payload)
	token.Wait()
	if token.Error() != nil {
		return "", token.Error()
	}
	return fmt.Sprintf("brk: %s, tpc: %s", datasink.Broker, datasink.Topic), nil
}

type MqttDatasource struct {
	Client                   mqtt.Client
	Broker                   string
	Backend                  string
	Destinations             []string
	Topic                    string
	QoS                      int
	Payload                  string
	TopicAttribute           string
	SimpleValueAttribute     string
	SimpleValueAttributeType string
	Rule                     string
}

var mqttClients = make(map[string]MqttDatasource)

//GetMQTTClients
func GetMQTTClients() map[string]MqttDatasource {
	return mqttClients
}

func init() {
	//	mqtt.DEBUG = orglog.New(os.Stdout, "DEBUG", 0)
	mqtt.ERROR = orglog.New(os.Stdout, "ERROR", 0)
}

func mqttStoreMessage(datasource MqttDatasource, msg mqtt.Message) {
	//log.Infof("MODEL: %s.%s TOPIC: %s  MSG: %s", datasource.Backend, datasource.Model, msg.Topic(), msg.Payload())
	data, err := prepareMessage(datasource, msg)
	if err != nil {
		log.Alertf("%v", err)
		return
	}

	if datasource.TopicAttribute != "" {
		data[datasource.TopicAttribute] = datasource.Topic
	}

	data, err = executeTransformationrule(datasource, data)
	if err != nil {
		log.Alertf("%v", err)
		return
	}

	for _, destination := range datasource.Destinations {
		if strings.HasPrefix(destination, "$model.") {
			modelname := strings.TrimPrefix(destination, "$model.")
			route := model.Route{
				Backend: datasource.Backend,
				Model:   modelname,
			}
			Store(route, data)
		} else {
			err := Destinations.Store(datasource.Backend, destination, data)
			if err != nil {
				log.Alertf("%v", err)
				return
			}
		}
	}
}

func executeTransformationrule(datasource MqttDatasource, data model.JSONMap) (model.JSONMap, error) {
	if datasource.Rule != "" {
		jsonBytes, err := json.Marshal(data)
		if err != nil {
			log.Alertf("%v", err)
			return nil, err
		}
		newJson, err := Rules.TransformJSON(datasource.Backend, datasource.Rule, jsonBytes)
		if err != nil {
			log.Alertf("%v", err)
			return nil, err
		}

		data = nil
		err = json.Unmarshal(newJson, &data)
		if err != nil {
			log.Alertf("%v", err)
			return nil, err
		}
		//fmt.Printf("src: %s\ndst: %s\n", string(jsonBytes), string(newJson))
	}
	return data, nil
}

func getSimpleDataAsModel(fieldname, fieldtype string, payload string) (model.JSONMap, error) {
	data := model.JSONMap{}
	var err error
	switch fieldtype {
	case model.FieldTypeInt:
		value, err := strconv.Atoi(payload)
		if err == nil {
			data[fieldname] = value
		}
	case model.FieldTypeFloat:
		value, err := strconv.ParseFloat(payload, 64)
		if err == nil {
			data[fieldname] = value
		}
	case model.FieldTypeTime:
		value, err := time.Parse(time.RFC3339, payload)
		if err != nil {
			saveerr := err
			var vint int
			vint, err = strconv.Atoi(payload)
			if err == nil {
				value = time.Unix(0, int64(vint)*int64(time.Millisecond))
			} else {
				err = saveerr
			}
		}
		if err == nil {
			data[fieldname] = value
		}
	case model.FieldTypeBool:
		value, err := strconv.ParseBool(payload)
		if err == nil {
			data[fieldname] = value
		}
	default:
		data[fieldname] = payload
	}
	if err != nil {
		return nil, err
	}
	return data, nil
}

func prepareMessage(datasource MqttDatasource, msg mqtt.Message) (model.JSONMap, error) {
	var data model.JSONMap
	data = nil
	switch strings.ToLower(datasource.Payload) {
	case "application/json":
		err := json.Unmarshal(msg.Payload(), &data)
		if err != nil {
			log.Alertf("%v", err)
			return nil, err
		}
	case "application/x.simple":
		added := false
		payload := string(msg.Payload())
		var err error
		data, err = getSimpleDataAsModel(datasource.SimpleValueAttribute, datasource.SimpleValueAttributeType, payload)
		if err != nil {
			log.Alertf("converting error on topic %s: %v", datasource.Topic, err)
			return nil, err
		}
		if !added {
			data[datasource.SimpleValueAttribute] = string(msg.Payload())
		}
	}
	return data, nil
}

func mqttConnectionLost(datasource MqttDatasource, c mqtt.Client, e error) {
	connected := false
	for !connected {
		err := mqttReconnect(c)
		if err != nil {
			log.Alertf("%v", err)
			time.Sleep(10 * time.Second)
			continue
		}
		connected = c.IsConnected()
	}

	subscribed := false
	for !subscribed {
		if !c.IsConnected() {
			mqttReconnect(c)
		}
		err := mqttSubscribe(datasource)
		if err != nil {
			log.Alertf("%v", err)
			time.Sleep(10 * time.Second)
			continue
		}
		subscribed = true
	}
	log.Infof("registering topic %s on %s for model %v", datasource.Topic, datasource.Broker, datasource.Destinations)
}

func mqttReconnect(c mqtt.Client) error {
	if !c.IsConnected() {
		token := c.Connect()
		token.Wait()
		err := token.Error()
		return err
	}
	return nil
}

func mqttSubscribe(datasource MqttDatasource) error {
	token := datasource.Client.Subscribe(datasource.Topic, byte(datasource.QoS), func(c mqtt.Client, m mqtt.Message) {
		mqttStoreMessage(datasource, m)
	})
	token.Wait()
	err := token.Error()
	return err
}

func mqttUnsubscribe(datasource MqttDatasource) error {
	token := datasource.Client.Unsubscribe(datasource.Topic)
	token.Wait()
	err := token.Error()
	return err
}

func getDatasinkMQTTClient(datasinkNsName string, backendname string, config model.DataSourceConfigMQTT) (MqttDatasource, error) {
	datasourceMqtt := MqttDatasource{
		Broker:                   config.Broker,
		Backend:                  backendname,
		Topic:                    config.Topic,
		QoS:                      config.QoS,
		Payload:                  config.Payload,
		TopicAttribute:           config.AddTopicAsAttribute,
		SimpleValueAttribute:     config.SimpleValueAttribute,
		SimpleValueAttributeType: config.SimpleValueAttributeType,
	}

	opts := mqtt.NewClientOptions().AddBroker(config.Broker).SetClientID(datasinkNsName)
	opts.SetKeepAlive(2 * time.Second)
	//opts.SetDefaultPublishHandler(f)
	opts.SetPingTimeout(1 * time.Second)
	opts.AutoReconnect = true

	opts.SetConnectionLostHandler(func(c mqtt.Client, err error) {
		mqttConnectionLost(datasourceMqtt, c, err)
	})
	if config.Username != "" {
		opts.CredentialsProvider = func() (string, string) {
			return config.Username, config.Password
		}
	}

	c := mqtt.NewClient(opts)
	datasourceMqtt.Client = c

	err := mqttReconnect(c)
	if err != nil {
		return MqttDatasource{}, err
	}

	mqttClients[datasinkNsName] = datasourceMqtt
	return datasourceMqtt, nil
}

func getDatasourceMQTTClient(clientID string, backendname string, datasource model.DataSource) (MqttDatasource, error) {
	destinationmodel := datasource.Destinations
	config := datasource.Config.(model.DataSourceConfigMQTT)

	datasourceMqtt := MqttDatasource{
		Broker:                   config.Broker,
		Backend:                  backendname,
		Destinations:             destinationmodel,
		Topic:                    config.Topic,
		QoS:                      config.QoS,
		Payload:                  config.Payload,
		TopicAttribute:           config.AddTopicAsAttribute,
		SimpleValueAttribute:     config.SimpleValueAttribute,
		SimpleValueAttributeType: config.SimpleValueAttributeType,
		Rule:                     datasource.Rule,
	}

	opts := mqtt.NewClientOptions().AddBroker(config.Broker).SetClientID(clientID)
	opts.SetKeepAlive(2 * time.Second)
	//opts.SetDefaultPublishHandler(f)
	opts.SetPingTimeout(1 * time.Second)
	opts.AutoReconnect = true

	opts.SetConnectionLostHandler(func(c mqtt.Client, err error) {
		mqttConnectionLost(datasourceMqtt, c, err)
	})
	if config.Username != "" {
		opts.CredentialsProvider = func() (string, string) {
			return config.Username, config.Password
		}
	}

	c := mqtt.NewClient(opts)
	datasourceMqtt.Client = c

	err := mqttReconnect(c)
	if err != nil {
		return MqttDatasource{}, err
	}

	datasourceNSName := GetMQTTClientNsName(datasourcePrefix, datasourceMqtt.Backend, datasource.Name)
	mqttClients[datasourceNSName] = datasourceMqtt
	return datasourceMqtt, nil
}

func mqttRegisterTopic(clientID string, backendname string, datasource model.DataSource) error {
	datasourceMqtt, err := getDatasourceMQTTClient(clientID, backendname, datasource)
	if err != nil {
		return err
	}

	err = mqttSubscribe(datasourceMqtt)
	if err != nil {
		return err
	}

	log.Infof("registering topic %s on %s for model %s", datasourceMqtt.Topic, datasourceMqtt.Broker, datasource.Destinations)
	return nil
}

func mqttDeregisterTopic(clientID string, backendname string, datasource model.DataSource) error {
	datasourceNSName := GetMQTTClientNsName(datasourcePrefix, backendname, datasource.Name)
	datasourceMqtt, ok := mqttClients[datasourceNSName]
	if ok {
		err := mqttUnsubscribe(datasourceMqtt)
		if err != nil {
			return err
		}
		datasourceMqtt.Client.Disconnect(1000)
		delete(mqttClients, datasourceNSName)
		log.Infof("deregistering topic %s on %s for model %s", datasourceMqtt.Topic, datasourceMqtt.Broker, datasource.Destinations)
	}
	return nil
}

func GetMQTTClientNsName(prefix, backend, dataname string) string {
	return fmt.Sprintf("%s.%s.%s", prefix, backend, dataname)
}