package devices

import (
	"context"
	"fmt"

	"git.zeroonesoft.cn/golib/xiaomihome/xiaomi"
)

// OccupancySensor 人在传感器读取接口（只读）。
type OccupancySensor interface {
	Device
	IsOccupied(ctx context.Context) (bool, error)
	GetIlluminance(ctx context.Context) (float64, error)

	OnPropsChanged(handler func(occupied bool, illuminance float64)) (string, error)
	GetProps() (bool, float64)
	FetchProps(ctx context.Context) (bool, float64, error)
}

type occupancyDevice struct {
	BaseDevice
	propOccupancy   siidPiid       // "occupancy" / "occupancy-status"（bool/uint8）
	propNoMotion    siidPiid       // "no-motion-duration"（uint16，linp.motion.* 等无 occupancy 属性的设备）
	propIlluminance siidPiid       // "illumination"
	propsCache      [2]interface{} // [0]=bool occupied, [1]=float64 lux
}

// occupied 根据设备支持的属性类型计算有人状态。
func (d *occupancyDevice) occupied(v interface{}) bool {
	if d.propOccupancy.valid {
		return toBool(v)
	}
	return toFloat(v) == 0 // no-motion-duration==0 → 有人
}

func NewOccupancySensor(client *xiaomi.Client, info *xiaomi.DeviceInfo) (OccupancySensor, 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 := &occupancyDevice{BaseDevice: BaseDevice{client: client, info: info}}
	for _, svc := range spec.Services {
		for _, prop := range svc.Properties {
			switch propertyShortName(prop.Type) {
			case "occupancy", "occupancy-status":
				if !d.propOccupancy.valid {
					d.propOccupancy = siidPiid{svc.IID, prop.PIID, true}
				}
			case "no-motion-duration":
				if !d.propNoMotion.valid {
					d.propNoMotion = siidPiid{svc.IID, prop.PIID, true}
				}
			case "illumination":
				if !d.propIlluminance.valid {
					d.propIlluminance = siidPiid{svc.IID, prop.PIID, true}
				}
			}
		}
	}
	if !d.propOccupancy.valid && !d.propNoMotion.valid {
		return nil, fmt.Errorf("%w: no occupancy/no-motion-duration property in SPEC", xiaomi.ErrNotSupported)
	}
	return d, nil
}

// occupiedProp 返回判断有人状态所用的属性。
func (d *occupancyDevice) occupiedProp() siidPiid {
	if d.propOccupancy.valid {
		return d.propOccupancy
	}
	return d.propNoMotion
}

func (d *occupancyDevice) IsOccupied(ctx context.Context) (bool, error) {
	p := d.occupiedProp()
	prop, err := d.GetProp(ctx, p.siid, p.piid)
	if err != nil {
		return false, err
	}
	return d.occupied(prop.Value), nil
}
func (d *occupancyDevice) GetIlluminance(ctx context.Context) (float64, error) {
	if !d.propIlluminance.valid {
		return 0, xiaomi.ErrNotSupported
	}
	prop, err := d.GetProp(ctx, d.propIlluminance.siid, d.propIlluminance.piid)
	if err != nil {
		return 0, err
	}
	return toFloat(prop.Value), nil
}

func (d *occupancyDevice) OnPropsChanged(handler func(occupied bool, illuminance float64)) (string, error) {
	if !d.propOccupancy.valid && !d.propNoMotion.valid && !d.propIlluminance.valid {
		return "", xiaomi.ErrNotSupported
	}
	return d.SubProp(0, 0, func(did string, prop *xiaomi.PropertyValue) {
		switch {
		case d.propOccupancy.valid && prop.SIID == d.propOccupancy.siid && prop.PIID == d.propOccupancy.piid:
			d.propsCache[0] = toBool(prop.Value)
		case d.propNoMotion.valid && prop.SIID == d.propNoMotion.siid && prop.PIID == d.propNoMotion.piid:
			d.propsCache[0] = toFloat(prop.Value) == 0
		case d.propIlluminance.valid && prop.SIID == d.propIlluminance.siid && prop.PIID == d.propIlluminance.piid:
			d.propsCache[1] = toFloat(prop.Value)
		}
		occ, _ := d.propsCache[0].(bool)
		lux, _ := d.propsCache[1].(float64)
		handler(occ, lux)
	})
}

func (d *occupancyDevice) GetProps() (bool, float64) {
	b, _ := d.propsCache[0].(bool)
	f, _ := d.propsCache[1].(float64)
	return b, f
}
func (d *occupancyDevice) FetchProps(ctx context.Context) (bool, float64, error) {
	keys := []xiaomi.PropKey{}
	p := d.occupiedProp()
	if p.valid {
		keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: p.siid, PIID: p.piid})
	}
	if d.propIlluminance.valid {
		keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propIlluminance.siid, PIID: d.propIlluminance.piid})
	}
	props, err := d.client.GetProps(ctx, keys)
	if err != nil {
		b, _ := d.propsCache[0].(bool)
		f, _ := d.propsCache[1].(float64)
		return b, f, err
	}
	var occupied bool
	var illuminance float64
	for _, r := range props {
		switch {
		case p.valid && r.SIID == p.siid && r.PIID == p.piid:
			occupied = d.occupied(r.Value)
		case d.propIlluminance.valid && r.SIID == d.propIlluminance.siid && r.PIID == d.propIlluminance.piid:
			illuminance = toFloat(r.Value)
		}
	}
	d.propsCache = [2]interface{}{occupied, illuminance}
	return occupied, illuminance, nil
}