/**
 * Sensor Feature
 * Provides read-only state for sensors (temperature, humidity, power, etc.)
 */

import { Feature, type TDeviceReference } from './feature.abstract.js';
import type { IFeatureOptions } from '../interfaces/feature.interfaces.js';
import type {
  TSensorProtocol,
  TSensorDeviceClass,
  TSensorStateClass,
  ISensorCapabilities,
  ISensorState,
  ISensorFeatureInfo,
  ISensorProtocolClient,
} from '../interfaces/smarthome.interfaces.js';

/**
 * Options for creating a SensorFeature
 */
export interface ISensorFeatureOptions extends IFeatureOptions {
  /** Protocol type */
  protocol: TSensorProtocol;
  /** Entity ID (for Home Assistant) */
  entityId: string;
  /** Protocol client for reading sensor state */
  protocolClient: ISensorProtocolClient;
  /** Device class (temperature, humidity, etc.) */
  deviceClass?: TSensorDeviceClass;
  /** State class (measurement, total, etc.) */
  stateClass?: TSensorStateClass;
  /** Unit of measurement */
  unit?: string;
  /** Precision (decimal places) */
  precision?: number;
}

/**
 * Sensor Feature - read-only state values
 *
 * Protocol-agnostic: works with Home Assistant, MQTT, SNMP, etc.
 *
 * @example
 * ```typescript
 * const sensor = device.getFeature<SensorFeature>('sensor');
 * if (sensor) {
 *   await sensor.refreshState();
 *   console.log(`Temperature: ${sensor.value} ${sensor.unit}`);
 * }
 * ```
 */
export class SensorFeature extends Feature {
  public readonly type = 'sensor' as const;
  public readonly protocol: TSensorProtocol;

  /** Entity ID (e.g., "sensor.living_room_temperature") */
  public readonly entityId: string;

  /** Capabilities */
  public readonly capabilities: ISensorCapabilities;

  /** Current state */
  protected _value: string | number | boolean = '';
  protected _numericValue?: number;
  protected _unit?: string;
  protected _lastUpdated: Date = new Date();

  /** Protocol client for reading sensor state */
  private protocolClient: ISensorProtocolClient;

  constructor(
    device: TDeviceReference,
    port: number,
    options: ISensorFeatureOptions
  ) {
    super(device, port, options);
    this.protocol = options.protocol;
    this.entityId = options.entityId;
    this.protocolClient = options.protocolClient;
    this.capabilities = {
      deviceClass: options.deviceClass,
      stateClass: options.stateClass,
      unit: options.unit,
      precision: options.precision,
    };
    this._unit = options.unit;
  }

  // ============================================================================
  // Properties
  // ============================================================================

  /**
   * Get current value (cached)
   */
  public get value(): string | number | boolean {
    return this._value;
  }

  /**
   * Get numeric value if available (cached)
   */
  public get numericValue(): number | undefined {
    return this._numericValue;
  }

  /**
   * Get unit of measurement
   */
  public get unit(): string | undefined {
    return this._unit;
  }

  /**
   * Get device class
   */
  public get deviceClass(): TSensorDeviceClass | undefined {
    return this.capabilities.deviceClass;
  }

  /**
   * Get state class
   */
  public get stateClass(): TSensorStateClass | undefined {
    return this.capabilities.stateClass;
  }

  /**
   * Get last updated timestamp
   */
  public get lastUpdated(): Date {
    return this._lastUpdated;
  }

  // ============================================================================
  // Connection
  // ============================================================================

  protected async doConnect(): Promise<void> {
    // Fetch initial state
    try {
      const state = await this.protocolClient.getState(this.entityId);
      this.updateStateInternal(state);
    } catch {
      // Ignore errors fetching initial state
    }
  }

  protected async doDisconnect(): Promise<void> {
    // Nothing to disconnect
  }

  // ============================================================================
  // Sensor Reading
  // ============================================================================

  /**
   * Refresh state from the device
   */
  public async refreshState(): Promise<ISensorState> {
    const state = await this.protocolClient.getState(this.entityId);
    this.updateStateInternal(state);
    return state;
  }

  /**
   * Update state from external source (e.g., state change event)
   */
  public updateState(state: ISensorState): void {
    this.updateStateInternal(state);
    this.emit('state:changed', state);
  }

  /**
   * Internal state update
   */
  private updateStateInternal(state: ISensorState): void {
    this._value = state.value;
    this._numericValue = state.numericValue;
    this._unit = state.unit || this._unit;
    this._lastUpdated = state.lastUpdated;
  }

  // ============================================================================
  // Feature Info
  // ============================================================================

  public getFeatureInfo(): ISensorFeatureInfo {
    return {
      ...this.getBaseFeatureInfo(),
      type: 'sensor',
      protocol: this.protocol,
      capabilities: this.capabilities,
      currentState: {
        value: this._value,
        numericValue: this._numericValue,
        unit: this._unit,
        lastUpdated: this._lastUpdated,
      },
    };
  }
}