package devices

import (
	"context"
	"fmt"

	"xiaomihome/xiaomi"
)

// TempHumiditySensor 温湿度传感器读取接口（只读）。
type TempHumiditySensor interface {
	Device
	GetTemperature(ctx context.Context) (float64, error)
	GetHumidity(ctx context.Context) (float64, error)

	OnPropsChanged(handler func(temp, humidity float64)) (string, error)
	GetProps() (float64, float64)
	FetchProps(ctx context.Context) (float64, float64, error)
}

type tempHumidityDevice struct {
	BaseDevice
	propTemp     siidPiid
	propHumidity siidPiid
	propsCache   [2]float64 // [0]=temperature, [1]=humidity
}

func NewTempHumiditySensor(client *xiaomi.Client, info *xiaomi.DeviceInfo) (TempHumiditySensor, error) {
	if info == nil { return nil, xiaomi.ErrDeviceNotFound }
	miotDev := client.GetMIoTDevice(info.DID)
	if miotDev == nil { return nil, fmt.Errorf("%w: device not initialized", xiaomi.ErrDeviceNotFound) }
	spec := miotDev.SpecInstance()
	if spec == nil { return nil, fmt.Errorf("%w: device has no SPEC information", xiaomi.ErrNotSupported) }
	d := &tempHumidityDevice{BaseDevice: BaseDevice{client: client, info: info}}
	for _, svc := range spec.Services {
		for _, prop := range svc.Properties {
			switch propertyShortName(prop.Type) {
			case "temperature":
				if !d.propTemp.valid { d.propTemp = siidPiid{svc.IID, prop.PIID, true} }
			case "relative-humidity":
				if !d.propHumidity.valid { d.propHumidity = siidPiid{svc.IID, prop.PIID, true} }
			}
		}
	}
	if !d.propTemp.valid && !d.propHumidity.valid {
		return nil, fmt.Errorf("%w: no temperature or humidity property in SPEC", xiaomi.ErrNotSupported)
	}
	return d, nil
}

func (d *tempHumidityDevice) GetTemperature(ctx context.Context) (float64, error) {
	if !d.propTemp.valid { return 0, xiaomi.ErrNotSupported }
	prop, err := d.GetProp(ctx, d.propTemp.siid, d.propTemp.piid)
	if err != nil { return 0, err }
	return toFloat(prop.Value), nil
}
func (d *tempHumidityDevice) GetHumidity(ctx context.Context) (float64, error) {
	if !d.propHumidity.valid { return 0, xiaomi.ErrNotSupported }
	prop, err := d.GetProp(ctx, d.propHumidity.siid, d.propHumidity.piid)
	if err != nil { return 0, err }
	return toFloat(prop.Value), nil
}

func (d *tempHumidityDevice) OnPropsChanged(handler func(temp, humidity float64)) (string, error) {
	if !d.propTemp.valid && !d.propHumidity.valid { return "", xiaomi.ErrNotSupported }
	return d.SubProp(0, 0, func(did string, prop *xiaomi.PropertyValue) {
		switch {
		case d.propTemp.valid && prop.SIID == d.propTemp.siid && prop.PIID == d.propTemp.piid:
			d.propsCache[0] = toFloat(prop.Value)
		case d.propHumidity.valid && prop.SIID == d.propHumidity.siid && prop.PIID == d.propHumidity.piid:
			d.propsCache[1] = toFloat(prop.Value)
		}
		handler(d.propsCache[0], d.propsCache[1])
	})
}

func (d *tempHumidityDevice) GetProps() (float64, float64) { return d.propsCache[0], d.propsCache[1] }
func (d *tempHumidityDevice) FetchProps(ctx context.Context) (float64, float64, error) {
	keys := []xiaomi.PropKey{}
	if d.propTemp.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propTemp.siid, PIID: d.propTemp.piid}) }
	if d.propHumidity.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propHumidity.siid, PIID: d.propHumidity.piid}) }
	props, err := d.client.GetProps(ctx, keys)
	if err != nil { return d.propsCache[0], d.propsCache[1], err }
	state := [2]float64{d.propsCache[0], d.propsCache[1]}
	for _, p := range props {
		switch {
		case d.propTemp.valid && p.SIID == d.propTemp.siid && p.PIID == d.propTemp.piid: state[0] = toFloat(p.Value)
		case d.propHumidity.valid && p.SIID == d.propHumidity.siid && p.PIID == d.propHumidity.piid: state[1] = toFloat(p.Value)
		}
	}
	d.propsCache = state
	return state[0], state[1], nil
}