package sensor

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

	"github.com/go-flucky/flucky/pkg/internal/format"
	"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
}

func (s *DHT11) ID() string {
	return s.SensorID
}

// Read measured values
func (s *DHT11) Read() ([]*types.MeasuredValue, 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, temperatureValue, err := dht.Read()
	if err != nil {
		return nil, fmt.Errorf("Read error: %v", err)
	}

	measuredValues := []*types.MeasuredValue{
		&types.MeasuredValue{
			ID:        uuid.NewV4().String(),
			Value:     float64(humidityValue),
			ValueType: types.MeasuredValueTypeHumidity,
			FromDate:  format.FormatedTime(),
			TillDate:  format.FormatedTime(),
			SensorID:  s.SensorID,
		},
		&types.MeasuredValue{
			ID:        uuid.NewV4().String(),
			Value:     float64(temperatureValue),
			ValueType: types.MeasuredValueTypeTemperature,
			FromDate:  format.FormatedTime(),
			TillDate:  format.FormatedTime(),
			SensorID:  s.SensorID,
		},
	}

	return measuredValues, nil
}

// ReadChannel reads the measured values from the sensor and writes them to a
// channel.
func (s *DHT11) ReadChannel(measuredValueChannel chan<- *types.MeasuredValue, errorChannel chan<- error, wg *sync.WaitGroup) {
	if wg != nil {
		defer wg.Done()
	}

	measuredValues, err := s.Read()
	if err != nil {
		errorChannel <- err
		return
	}

	for _, measuredValue := range measuredValues {
		measuredValueChannel <- measuredValue
	}

}

// ReadContinously reads the measured values continously from the sensor and
// writes them to a channel.
func (s *DHT11) ReadContinously(ctx context.Context, measuredValueChannel chan<- *types.MeasuredValue, errorChannel chan<- error) {
	for {
		select {
		case <-ctx.Done():
			errorChannel <- fmt.Errorf("%v: Context closed: %v", s.SensorName, ctx.Err())
			return
		default:
			s.ReadChannel(measuredValueChannel, errorChannel, nil)
		}
	}
}

// Ticker returns a new ticker, which tick every when the sensor should be read
func (s *DHT11) Ticker() *time.Ticker {
	duration, err := time.ParseDuration(s.TickDuration)
	if err != nil {
		duration = time.Minute
	}
	return time.NewTicker(duration)
}