package devices

import (
	"context"
	"xiaomihome/xiaomi"
)

// Light 灯光统一控制接口
type Light interface {
	Device
	TurnOn(ctx context.Context) error
	TurnOff(ctx context.Context) error
	Toggle(ctx context.Context) error

	// 能力查询
	HasBrightness() bool
	HasColorTemp() bool
	HasColor() bool

	// 亮度 (1-100)
	SetBrightness(ctx context.Context, pct int) error
	GetBrightness(ctx context.Context) (int, error)

	// 色温 (2700-6500K)
	SetColorTemp(ctx context.Context, kelvin int) error
	GetColorTemp(ctx context.Context) (int, error)

	// 颜色 (0-255)
	SetColor(ctx context.Context, r, g, b int) error
	GetColor(ctx context.Context) (r, g, b int, err error)

	OnStateChanged(handler func(state LightState, changed string)) (string, error)
	GetState() LightState
	FetchState(ctx context.Context) (LightState, error)
}

// LightState 灯光完整状态（字段名对齐 SPEC type）
type LightState struct {
	On               bool   `json:"on"`                // SPEC: "on"
	Brightness       int    `json:"brightness"`        // SPEC: "brightness"
	ColorTemperature int    `json:"colorTemperature"`  // SPEC: "color-temperature"
	ColorRGB         [3]int `json:"colorRgb"`          // SPEC: "color"
}

type lightDevice struct {
	BaseDevice
	propOn         siidPiid // "on"
	propBrightness siidPiid // "brightness"
	propColorTemp  siidPiid // "color-temperature"
	propColor      siidPiid // "color"

	stateCache LightState // MQTT 推送维护的本地缓存
}

// NewLight creates a Light control for the given device.
func NewLight(client *xiaomi.Client, info *xiaomi.DeviceInfo) (Light, error) {
	d := &lightDevice{
		BaseDevice: NewBaseDevice(client, info),
	}

	resolver := d.getSpecResolver()
	if resolver == nil {
		return nil, xiaomi.ErrNoSPEC
	}

	// "on" is required
	siid, piid, ok := resolver.find("on")
	if !ok {
		return nil, xiaomi.ErrNotSupported
	}
	d.propOn = siidPiid{siid, piid, true}

	// Optional properties
	if s, p, ok := resolver.find("brightness"); ok {
		d.propBrightness = siidPiid{s, p, true}
	}
	if s, p, ok := resolver.find("color-temperature"); ok {
		d.propColorTemp = siidPiid{s, p, true}
	}
	if s, p, ok := resolver.find("color"); ok {
		d.propColor = siidPiid{s, p, true}
	}

	return d, nil
}

func (d *lightDevice) TurnOn(ctx context.Context) error {
	if !d.propOn.valid {
		return xiaomi.ErrNotSupported
	}
	return d.SetProp(ctx, d.propOn.siid, d.propOn.piid, true)
}

func (d *lightDevice) TurnOff(ctx context.Context) error {
	if !d.propOn.valid {
		return xiaomi.ErrNotSupported
	}
	return d.SetProp(ctx, d.propOn.siid, d.propOn.piid, false)
}

func (d *lightDevice) Toggle(ctx context.Context) error {
	on, err := d.isOn(ctx)
	if err != nil {
		return err
	}
	if on {
		return d.TurnOff(ctx)
	}
	return d.TurnOn(ctx)
}

func (d *lightDevice) isOn(ctx context.Context) (bool, error) {
	prop, err := d.GetProp(ctx, d.propOn.siid, d.propOn.piid)
	if err != nil {
		return false, err
	}
	if b, ok := prop.Value.(bool); ok {
		return b, nil
	}
	return false, nil
}

func (d *lightDevice) HasBrightness() bool { return d.propBrightness.valid }
func (d *lightDevice) HasColorTemp() bool  { return d.propColorTemp.valid }
func (d *lightDevice) HasColor() bool      { return d.propColor.valid }

func (d *lightDevice) SetBrightness(ctx context.Context, pct int) error {
	if !d.propBrightness.valid {
		return xiaomi.ErrNotSupported
	}
	return d.SetProp(ctx, d.propBrightness.siid, d.propBrightness.piid, pct)
}

func (d *lightDevice) GetBrightness(ctx context.Context) (int, error) {
	if !d.propBrightness.valid {
		return 0, xiaomi.ErrNotSupported
	}
	prop, err := d.GetProp(ctx, d.propBrightness.siid, d.propBrightness.piid)
	if err != nil {
		return 0, err
	}
	return toInt(prop.Value), nil
}

func (d *lightDevice) SetColorTemp(ctx context.Context, kelvin int) error {
	if !d.propColorTemp.valid {
		return xiaomi.ErrNotSupported
	}
	return d.SetProp(ctx, d.propColorTemp.siid, d.propColorTemp.piid, kelvin)
}

func (d *lightDevice) GetColorTemp(ctx context.Context) (int, error) {
	if !d.propColorTemp.valid {
		return 0, xiaomi.ErrNotSupported
	}
	prop, err := d.GetProp(ctx, d.propColorTemp.siid, d.propColorTemp.piid)
	if err != nil {
		return 0, err
	}
	return toInt(prop.Value), nil
}

func (d *lightDevice) SetColor(ctx context.Context, r, g, b int) error {
	if !d.propColor.valid {
		return xiaomi.ErrNotSupported
	}
	colorVal := (r << 16) | (g << 8) | b
	return d.SetProp(ctx, d.propColor.siid, d.propColor.piid, colorVal)
}

func (d *lightDevice) GetColor(ctx context.Context) (r, g, b int, err error) {
	if !d.propColor.valid {
		return 0, 0, 0, xiaomi.ErrNotSupported
	}
	prop, err := d.GetProp(ctx, d.propColor.siid, d.propColor.piid)
	if err != nil {
		return 0, 0, 0, err
	}
	val := toInt(prop.Value)
	r = (val >> 16) & 0xFF
	g = (val >> 8) & 0xFF
	b = val & 0xFF
	return r, g, b, nil
}

func (d *lightDevice) OnStateChanged(handler func(state LightState, changed string)) (string, error) {
	type field struct {
		siid, piid int
		name       string
		fill       func(*LightState, interface{})
	}
	var fields []field
	if d.propOn.valid {
		fields = append(fields, field{d.propOn.siid, d.propOn.piid, "on",
			func(s *LightState, v interface{}) { s.On, _ = v.(bool) }})
	}
	if d.propBrightness.valid {
		fields = append(fields, field{d.propBrightness.siid, d.propBrightness.piid, "brightness",
			func(s *LightState, v interface{}) { s.Brightness = toInt(v) }})
	}
	if d.propColorTemp.valid {
		fields = append(fields, field{d.propColorTemp.siid, d.propColorTemp.piid, "color-temperature",
			func(s *LightState, v interface{}) { s.ColorTemperature = toInt(v) }})
	}
	if d.propColor.valid {
		fields = append(fields, field{d.propColor.siid, d.propColor.piid, "color",
			func(s *LightState, v interface{}) {
				if v, ok := v.(float64); ok {
					c := int(v)
					s.ColorRGB = [3]int{(c >> 16) & 0xFF, (c >> 8) & 0xFF, c & 0xFF}
				}
			}})
	}
	if len(fields) == 0 {
		return "", xiaomi.ErrNotSupported
	}
	return d.SubProp(0, 0, func(did string, prop *xiaomi.PropertyValue) {
		for _, f := range fields {
			if f.siid == prop.SIID && f.piid == prop.PIID {
				f.fill(&d.stateCache, prop.Value)
				handler(d.stateCache, f.name)
				return
			}
		}
	})
}

// toInt converts an interface{} value to int.
func toInt(v interface{}) int {
	switch n := v.(type) {
	case float64:
		return int(n)
	case int:
		return n
	case int64:
		return int(n)
	case uint8:
		return int(n)
	case uint16:
		return int(n)
	case uint32:
		return int(n)
	}
	return 0
}

func (d *lightDevice) GetState() LightState { return d.stateCache }
func (d *lightDevice) FetchState(ctx context.Context) (LightState, error) {
	keys := []xiaomi.PropKey{}
	if d.propOn.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propOn.siid, PIID: d.propOn.piid}) }
	if d.propBrightness.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propBrightness.siid, PIID: d.propBrightness.piid}) }
	if d.propColorTemp.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propColorTemp.siid, PIID: d.propColorTemp.piid}) }
	if d.propColor.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propColor.siid, PIID: d.propColor.piid}) }
	props, err := d.client.GetProps(ctx, keys)
	if err != nil { return d.stateCache, err }
	state := LightState{}
	for _, p := range props {
		switch {
		case d.propOn.valid && p.SIID == d.propOn.siid && p.PIID == d.propOn.piid: state.On, _ = p.Value.(bool)
		case d.propBrightness.valid && p.SIID == d.propBrightness.siid && p.PIID == d.propBrightness.piid: state.Brightness = toInt(p.Value)
		case d.propColorTemp.valid && p.SIID == d.propColorTemp.siid && p.PIID == d.propColorTemp.piid: state.ColorTemperature = toInt(p.Value)
		case d.propColor.valid && p.SIID == d.propColor.siid && p.PIID == d.propColor.piid:
			if v, ok := p.Value.(float64); ok { c := int(v); state.ColorRGB = [3]int{(c>>16)&0xFF, (c>>8)&0xFF, c&0xFF} }
		}
	}
	d.stateCache = state
	return state, nil
}