package sensor

import (
	"context"
	"fmt"
	"math"
	"sync"
	"time"

	"github.com/go-flucky/flucky/pkg/types"
	"github.com/go-flucky/go-dht"
	uuid "github.com/satori/go.uuid"
)

// DHT11 is a sensor to measure humidity and temperature.
type DHT11 struct {
	*types.Sensor
}

// GetSensorModel returns the sensor model
func (s *DHT11) GetSensorModel() types.SensorModel {
	return s.Sensor.SensorModel
}

// ReadHumidity measure the humidity
func (s *DHT11) ReadHumidity(round float64) (*types.Humidity, error) {
	err := dht.HostInit()
	if err != nil {
		return nil, fmt.Errorf("HostInit error: %v", err)
	}

	gpio, err := types.GPIOToString(*s.GPIONumber)
	if err != nil {
		return nil, err
	}

	dht, err := dht.NewDHT(gpio, dht.Celsius, "")
	if err != nil {
		return nil, fmt.Errorf("NewDHT error: %v", err)
	}

	humidityValue, _, err := dht.Read()
	if err != nil {
		return nil, fmt.Errorf("Read error: %v", err)
	}

	if round != 0 {
		humidityValue = math.Round(humidityValue/round) * round
	}

	humidity := &types.Humidity{
		HumidityID:       uuid.NewV4().String(),
		HumidityValue:    humidityValue,
		HumidityFromDate: time.Now(),
		HumidityTillDate: time.Now(),
		SensorID:         s.SensorID,
	}

	return humidity, nil
}

// ReadHumidityWriteIntoChannel and write values into a channel
func (s *DHT11) ReadHumidityWriteIntoChannel(round float64, humidityChannel chan<- *types.Humidity, errorChannel chan<- error, wg *sync.WaitGroup) {
	if wg != nil {
		defer wg.Done()
	}

	humidity, err := s.ReadHumidity(round)
	if err != nil {
		errorChannel <- err
		return
	}
	humidityChannel <- humidity
}

// ReadHumidityContinously into a channel until context closed
func (s *DHT11) ReadHumidityContinously(ctx context.Context, round float64, humidityChannel chan<- *types.Humidity, errorChannel chan<- error) {
	for {
		select {
		case <-ctx.Done():
			errorChannel <- fmt.Errorf("%v: Context closed: %v", s.SensorName, ctx.Err())
			return
		default:
			s.ReadHumidityWriteIntoChannel(round, humidityChannel, errorChannel, nil)
		}
	}
}

// ReadTemperature measure the temperature
func (s *DHT11) ReadTemperature(degree types.Degree, round float64) (*types.Temperature, error) {
	err := dht.HostInit()
	if err != nil {
		return nil, fmt.Errorf("HostInit error: %v", err)
	}

	gpio, err := types.GPIOToString(*s.GPIONumber)
	if err != nil {
		return nil, err
	}

	dht, err := dht.NewDHT(gpio, dht.Celsius, "")
	if err != nil {
		return nil, fmt.Errorf("NewDHT error: %v", err)
	}

	_, temperatureValue, err := dht.Read()
	if err != nil {
		return nil, fmt.Errorf("Read error: %v", err)
	}

	// Convert temperature degree
	temperatureValue = convertTemperatureMeasurementUnit(temperatureValue, types.DegreeCelsius, degree)

	if round != 0 {
		temperatureValue = math.Round(temperatureValue/round) * round
	}

	temperature := &types.Temperature{
		TemperatureID:       uuid.NewV4().String(),
		TemperatureValue:    temperatureValue,
		TemperatureDegree:   degree,
		TemperatureFromDate: time.Now(),
		TemperatureTillDate: time.Now(),
		SensorID:            s.SensorID,
	}

	return temperature, nil
}

// ReadTemperatureWriteIntoChannel and write values into a channel
func (s *DHT11) ReadTemperatureWriteIntoChannel(degree types.Degree, round float64, temperatureChannel chan<- *types.Temperature, errorChannel chan<- error, wg *sync.WaitGroup) {
	if wg != nil {
		defer wg.Done()
	}

	temperature, err := s.ReadTemperature(degree, round)
	if err != nil {
		errorChannel <- err
		return
	}
	temperatureChannel <- temperature
}

// ReadTemperatureContinously into a channel until context closed
func (s *DHT11) ReadTemperatureContinously(ctx context.Context, degree types.Degree, round float64, temperatureChannel chan<- *types.Temperature, errorChannel chan<- error) {
	for {
		select {
		case <-ctx.Done():
			errorChannel <- fmt.Errorf("%v: Context closed: %v", s.SensorName, ctx.Err())
			return
		default:
			s.ReadTemperatureWriteIntoChannel(degree, round, temperatureChannel, errorChannel, nil)
		}
	}
}