// Package devices provides strongly-typed device control abstractions for
// Xiaomi smart home devices. Each device type defines an interface that hides
// siid/piid details behind semantic methods like SetTargetTemp() and SetMode().
//
// The package uses SPEC property resolution to automatically discover the
// correct siid/piid mappings for each device model, enabling cross-model
// compatibility without hardcoded property IDs.
package devices

import (
	"context"
	"strings"

	"xiaomihome/miot"
	"xiaomihome/xiaomi"
)

// Device is the common interface shared by all device control types.
// All device kinds (Switch, Light, AirConditioner, etc.) embed this interface.
type Device interface {
	// DID returns the device's unique identifier.
	DID() string
	// Name returns the device's display name.
	Name() string
	// Model returns the device's model identifier.
	Model() string
	// Online returns whether the device is currently online.
	Online() bool
	// Info returns the full device information.
	Info() *xiaomi.DeviceInfo
}

// BaseDevice provides common functionality shared by all device types.
// Each device type embeds BaseDevice and extends it with type-specific methods.
// BaseDevice implements the Device interface.
type BaseDevice struct {
	client   *xiaomi.Client
	info     *xiaomi.DeviceInfo
	miotDev  *miot.MIoTDevice
	resolver *specResolver // cached SPEC resolver (created on demand)
}

// NewBaseDevice creates a new BaseDevice instance.
func NewBaseDevice(client *xiaomi.Client, info *xiaomi.DeviceInfo) BaseDevice {
	return BaseDevice{
		client: client,
		info:   info,
	}
}

// DID returns the device's unique identifier.
func (d *BaseDevice) DID() string {
	return d.info.DID
}

// Name returns the device's display name.
func (d *BaseDevice) Name() string {
	return d.info.Name
}

// Model returns the device's model identifier.
func (d *BaseDevice) Model() string {
	return d.info.Model
}

// Online returns whether the device is currently online.
func (d *BaseDevice) Online() bool {
	return d.info.Online
}

// Info returns the full device information.
func (d *BaseDevice) Info() *xiaomi.DeviceInfo {
	return d.info
}

// GetProp reads a single property value from the device.
func (d *BaseDevice) GetProp(ctx context.Context, siid, piid int) (*xiaomi.PropertyValue, error) {
	return d.client.GetProp(ctx, d.info.DID, siid, piid)
}

// SetProp writes a single property value to the device.
func (d *BaseDevice) SetProp(ctx context.Context, siid, piid int, value interface{}) error {
	return d.client.SetProp(ctx, d.info.DID, siid, piid, value)
}

// Action invokes a device action.
func (d *BaseDevice) Action(ctx context.Context, siid, aiid int, params []interface{}) (*xiaomi.ActionResult, error) {
	return d.client.Action(ctx, d.info.DID, siid, aiid, params)
}

// SubProp subscribes to property change notifications.
func (d *BaseDevice) SubProp(siid, piid int, handler xiaomi.PropHandler) (string, error) {
	return d.client.SubProp(d.info.DID, siid, piid, handler)
}

// SubEvent subscribes to event notifications.
func (d *BaseDevice) SubEvent(siid, eiid int, handler xiaomi.EventHandler) (string, error) {
	return d.client.SubEvent(d.info.DID, siid, eiid, handler)
}

// SubDeviceState subscribes to online/offline state changes.
func (d *BaseDevice) SubDeviceState(handler xiaomi.DeviceStateHandler) error {
	return d.client.SubDeviceState(d.info.DID, handler)
}

// getMIoTDevice returns the underlying MIoTDevice (lazy-loaded).
func (d *BaseDevice) getMIoTDevice() *miot.MIoTDevice {
	if d.miotDev == nil {
		d.miotDev = d.client.GetMIoTDevice(d.info.DID)
	}
	return d.miotDev
}

// getSpecResolver returns a SPEC property resolver (lazy-loaded).
func (d *BaseDevice) getSpecResolver() *specResolver {
	if d.resolver == nil {
		dev := d.getMIoTDevice()
		if dev != nil {
			d.resolver = newSpecResolver(dev.SpecInstance())
		}
	}
	return d.resolver
}

// specResolver is a thin wrapper to avoid importing specs package in every device file.
type specResolver struct {
	byType map[string]*miot.MIoTSpecProperty
}

func newSpecResolver(spec *miot.MIoTSpecInstance) *specResolver {
	if spec == nil {
		return nil
	}
	r := &specResolver{
		byType: make(map[string]*miot.MIoTSpecProperty),
	}
	for _, svc := range spec.Services {
		for i := range svc.Properties {
			prop := svc.Properties[i]
			name := propertyShortName(prop.Type)
			if name != "" {
				if _, exists := r.byType[name]; !exists {
					r.byType[name] = prop
				}
			}
		}
	}
	return r
}

// propertyShortName extracts the short name from a SPEC property URN.
// E.g., "urn:miot-spec-v2:property:on:00000006:..." → "on".
func propertyShortName(urn string) string {
	parts := strings.Split(urn, ":")
	if len(parts) >= 4 && parts[2] == "property" {
		return parts[3]
	}
	return urn
}

func (r *specResolver) find(propType string) (siid, piid int, found bool) {
	if r == nil {
		return 0, 0, false
	}
	if prop, ok := r.byType[propType]; ok {
		return prop.SIID, prop.PIID, true
	}
	return 0, 0, false
}