package sensors

import (
	"errors"
	"slices"
	"time"
)

func (s *Sensor) Validate() error {
	if s.SensorID == "" {
		return ErrInvalidSensorIdentifier
	}
	if s.SensorType == "" {
		return ErrInvalidSensorType
	}

	validTypes := []SType{Temperature, Humidity, CarbonDioxide, Pressure, Proximity, Light}
	isValid := slices.Contains(validTypes, s.SensorType)
	if !isValid {
		return ErrInvalidSensorType
	}

	if s.SamplingInterval == nil {
		defaultInterval := time.Second * 3600
		s.SamplingInterval = &defaultInterval
	}

	if s.ThresholdAbove == nil {
		defaultAbove := 100.0
		s.ThresholdAbove = &defaultAbove
	}

	if s.ThresholdBelow == nil {
		defaultBelow := 0.0
		s.ThresholdBelow = &defaultBelow
	}

	return nil
}

func (d *SensorData) Validate() error {
	if d.SensorID == "" {
		return ErrInvalidSensorIdentifier
	}

	if d.Value == nil {
		return ErrMissingValue
	}

	if d.Timestamp == nil {
		now := time.Now()
		d.Timestamp = &now
	}

	return nil
}

// TODO: implement this in service layer for alerts
func (d *SensorData) IsOutOfRangeAbove(sensor Sensor) bool {
	if d.Value == nil || sensor.ThresholdAbove == nil {
		return false
	}
	return *d.Value > *sensor.ThresholdAbove
}

func (d *SensorData) IsOutOfRangeBelow(sensor Sensor) bool {
	if d.Value == nil || sensor.ThresholdBelow == nil {
		return false
	}
	return *d.Value < *sensor.ThresholdBelow
}

func (r *SensorRequest) Validate() error {
	if r.SensorID == "" {
		return ErrInvalidSensorIdentifier
	}
	return nil
}

func (r *SensorDataRequest) Validate() error {
	if r.SensorID == "" {
		return ErrInvalidSensorIdentifier
	}

	if r.To == nil || *r.To == "" {
		defaultTo := time.Now().Format(time.RFC3339)
		r.To = &defaultTo
	} else {
		if _, err := time.Parse(time.RFC3339, *r.To); err != nil {
			defaultTo := time.Now().Format(time.RFC3339)
			r.To = &defaultTo
		}
	}

	if r.From == nil || *r.From == "" {
		defaultFrom := time.Now().AddDate(0, 0, -7).Format(time.RFC3339)
		r.From = &defaultFrom
	} else {
		if _, err := time.Parse(time.RFC3339, *r.From); err != nil {
			defaultFrom := time.Now().AddDate(0, 0, -7).Format(time.RFC3339)
			r.From = &defaultFrom
		}
	}

	return nil
}

var (
	ErrRegisteringSensor       = errors.New("error registering sensor")
	ErrUpdatingSensor          = errors.New("error updating sensor")
	ErrInvalidSensorIdentifier = errors.New("sensor identifier is required")
	ErrInvalidSensorType       = errors.New("sensor type is required")
	ErrSensorNotFound          = errors.New("sensor not found")
	ErrMissingValue            = errors.New("sensor value no provided")
	ErrSensorAlreadyExists     = errors.New("sensor already exists")
)