import { logger } from '../utils/logger';

export interface TrackingPoint {
  timestamp: Date;
  location: string;
  status: string;
  description: string;
  coordinates?: { lat: number; lng: number };
}

export interface PackageTelemetry {
  trackingNumber: string;
  currentStatus: string;
  estimatedDelivery: Date;
  history: TrackingPoint[];
  lastUpdate: Date;
}

/**
 * [BIZ_TRADE_10] 跨境物流包裹实时状态遥测 (Logistic Telemetry)
 * @description 提供包裹位置与状态的实时追踪与可视化数据源，支持全链路轨迹动态感知
 */
export class LogisticTelemetryService {
  /**
   * 获取包裹实时遥测数据
   */
  static async getTelemetry(trackingNumber: string): Promise<PackageTelemetry> {
    logger.info(`[LogisticTelemetry] Fetching real-time status for: ${trackingNumber}`);

    // 模拟从第三方物流 API 获取数据
    const telemetry: PackageTelemetry = {
      trackingNumber,
      currentStatus: 'IN_TRANSIT',
      estimatedDelivery: new Date(Date.now() + 5 * 24 * 60 * 60 * 1000),
      lastUpdate: new Date(),
      history: [
        { 
          timestamp: new Date(Date.now() - 2 * 24 * 60 * 60 * 1000), 
          location: 'Shanghai, CN', 
          status: 'PICKED_UP', 
          description: 'Package picked up by carrier',
          coordinates: { lat: 31.2304, lng: 121.4737 }
        },
        { 
          timestamp: new Date(Date.now() - 1 * 24 * 60 * 60 * 1000), 
          location: 'Shanghai Pudong Airport', 
          status: 'DEPARTED', 
          description: 'Package departed from facility',
          coordinates: { lat: 31.1443, lng: 121.8083 }
        },
        { 
          timestamp: new Date(), 
          location: 'Over the Pacific Ocean', 
          status: 'IN_TRANSIT', 
          description: 'Flight in progress'
        }
      ]
    };

    return telemetry;
  }

  /**
   * 模拟轨迹推演 (用于前端平滑动画)
   */
  static predictCurrentLocation(telemetry: PackageTelemetry): { lat: number; lng: number } {
    // 逻辑：基于上一个已知点与目的地，根据时间差进行线性插值推演
    // 简单返回一个模拟点
    return { lat: 37.7749, lng: -122.4194 }; // 模拟接近旧金山
  }
}
