package devices

import (
	"context"
	"xiaomihome/xiaomi"
)

// Fan 风扇统一控制接口
type Fan interface {
	Device
	TurnOn(ctx context.Context) error
	TurnOff(ctx context.Context) error
	IsOn(ctx context.Context) (bool, error)

	SetFanLevel(ctx context.Context, level int) error // 0=off, 1-4 档位
	GetFanLevel(ctx context.Context) (int, error)

	SetOscillation(ctx context.Context, on bool) error
	IsOscillating(ctx context.Context) (bool, error)

	SetNaturalWind(ctx context.Context, on bool) error
	IsNaturalWind(ctx context.Context) (bool, error)

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

// FanState 风扇完整状态（MQTT 缓存）
type FanState struct {
	On          bool `json:"on"`
	FanLevel    int  `json:"fanLevel"`
	Oscillation bool `json:"oscillation"`
	NaturalWind bool `json:"naturalWind"`
}

type fanDevice struct {
	BaseDevice
	propOn          siidPiid // "on"
	propFanLevel    siidPiid // "fan-level"
	propOscillation siidPiid // "horizontal-swing" or "oscillation"
	propNaturalWind siidPiid // "mode" (natural wind mode)

	stateCache FanState
}

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

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

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

	if s, p, ok := resolver.find("fan-level"); ok {
		d.propFanLevel = siidPiid{s, p, true}
	}
	if s, p, ok := resolver.find("horizontal-swing"); ok {
		d.propOscillation = siidPiid{s, p, true}
	}
	if s, p, ok := resolver.find("mode"); ok {
		d.propNaturalWind = siidPiid{s, p, true}
	}

	return d, nil
}

func (d *fanDevice) 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 *fanDevice) 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 *fanDevice) IsOn(ctx context.Context) (bool, error) {
	if !d.propOn.valid {
		return false, xiaomi.ErrNotSupported
	}
	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 *fanDevice) SetFanLevel(ctx context.Context, level int) error {
	if !d.propFanLevel.valid {
		return xiaomi.ErrNotSupported
	}
	return d.SetProp(ctx, d.propFanLevel.siid, d.propFanLevel.piid, level)
}

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

func (d *fanDevice) SetOscillation(ctx context.Context, on bool) error {
	if !d.propOscillation.valid {
		return xiaomi.ErrNotSupported
	}
	return d.SetProp(ctx, d.propOscillation.siid, d.propOscillation.piid, on)
}

func (d *fanDevice) IsOscillating(ctx context.Context) (bool, error) {
	if !d.propOscillation.valid {
		return false, xiaomi.ErrNotSupported
	}
	prop, err := d.GetProp(ctx, d.propOscillation.siid, d.propOscillation.piid)
	if err != nil {
		return false, err
	}
	if b, ok := prop.Value.(bool); ok {
		return b, nil
	}
	return false, nil
}

func (d *fanDevice) SetNaturalWind(ctx context.Context, on bool) error {
	if !d.propNaturalWind.valid {
		return xiaomi.ErrNotSupported
	}
	mode := 0 // normal
	if on {
		mode = 1 // natural wind
	}
	return d.SetProp(ctx, d.propNaturalWind.siid, d.propNaturalWind.piid, mode)
}

func (d *fanDevice) IsNaturalWind(ctx context.Context) (bool, error) {
	if !d.propNaturalWind.valid {
		return false, xiaomi.ErrNotSupported
	}
	prop, err := d.GetProp(ctx, d.propNaturalWind.siid, d.propNaturalWind.piid)
	if err != nil {
		return false, err
	}
	return toInt(prop.Value) == 1, nil
}

func (d *fanDevice) OnStateChanged(handler func(state FanState, changed string)) (string, error) {
	type field struct{ siid, piid int; name string; fill func(*FanState, interface{}) }
	var fields []field
	if d.propOn.valid {
		fields = append(fields, field{d.propOn.siid, d.propOn.piid, "on",
			func(s *FanState, v interface{}) { s.On, _ = v.(bool) }})
	}
	if d.propFanLevel.valid {
		fields = append(fields, field{d.propFanLevel.siid, d.propFanLevel.piid, "fan-level",
			func(s *FanState, v interface{}) { s.FanLevel = toInt(v) }})
	}
	if d.propOscillation.valid {
		fields = append(fields, field{d.propOscillation.siid, d.propOscillation.piid, "swing",
			func(s *FanState, v interface{}) { s.Oscillation, _ = v.(bool) }})
	}
	if d.propNaturalWind.valid {
		fields = append(fields, field{d.propNaturalWind.siid, d.propNaturalWind.piid, "mode",
			func(s *FanState, v interface{}) { s.NaturalWind = toInt(v) == 1 }})
	}
	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
			}
		}
	})
}

func (d *fanDevice) GetState() FanState { return d.stateCache }
func (d *fanDevice) FetchState(ctx context.Context) (FanState, 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.propFanLevel.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propFanLevel.siid, PIID: d.propFanLevel.piid}) }
	if d.propOscillation.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propOscillation.siid, PIID: d.propOscillation.piid}) }
	if d.propNaturalWind.valid { keys = append(keys, xiaomi.PropKey{DID: d.info.DID, SIID: d.propNaturalWind.siid, PIID: d.propNaturalWind.piid}) }
	props, err := d.client.GetProps(ctx, keys)
	if err != nil { return d.stateCache, err }
	state := FanState{}
	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.propFanLevel.valid && p.SIID == d.propFanLevel.siid && p.PIID == d.propFanLevel.piid: state.FanLevel = toInt(p.Value)
		case d.propOscillation.valid && p.SIID == d.propOscillation.siid && p.PIID == d.propOscillation.piid: state.Oscillation, _ = p.Value.(bool)
		case d.propNaturalWind.valid && p.SIID == d.propNaturalWind.siid && p.PIID == d.propNaturalWind.piid: state.NaturalWind = toInt(p.Value) == 1
		}
	}
	d.stateCache = state
	return state, nil
}