import * as crypto from 'crypto';
import { logger } from '../utils/logger';
import { ConfigService } from './ConfigService';

/**
 * PlatformApiService - 平台API对接服务
 * 
 * 功能定位：
 * - 仅处理有API平台的对接（Amazon MWS, eBay API, Shopee Open API等）
 * - 无API平台（TikTok Shop, Temu等）的采集由浏览器插件处理
 * 
 * 安全约束：
 * - 严禁在后端进行网页爬取（避免服务器IP被封）
 * - 所有API调用需携带traceId和tenantId
 * 
 * @author AI-Backend-1
 * @taskId BE-P005, BE-P006, BE-P007
 */

export interface PlatformApiConfig {
  platform: 'AMAZON' | 'EBAY' | 'SHOPEE' | 'ALIEXPRESS';
  apiKey: string;
  apiSecret: string;
  accessToken?: string;
  refreshToken?: string;
  marketplaceId?: string;
}

export interface SyncOptions {
  tenantId: string;
  shopId: string;
  traceId: string;
  taskId?: string;
  businessType: 'TOC' | 'TOB';
  startDate?: Date;
  endDate?: Date;
  limit?: number;
}

export interface ProductSyncResult {
  platformProductId: string;
  title: string;
  price: number;
  currency: string;
  stock: number;
  status: string;
  syncedAt: Date;
}

export interface OrderSyncResult {
  platformOrderId: string;
  status: string;
  totalAmount: number;
  currency: string;
  items: Array<{
    sku: string;
    quantity: number;
    unitPrice: number;
  }>;
  syncedAt: Date;
}

export class PlatformApiService {
  private static readonly API_ENDPOINTS = {
    AMAZON: 'https://sellingpartnerapi-na.amazon.com',
    EBAY: 'https://api.ebay.com/sell',
    SHOPEE: 'https://partner.shopeemobile.com/api/v2',
    ALIEXPRESS: 'https://openapi.aliexpress.com',
  };

  private static readonly RATE_LIMITS = {
    AMAZON: { requests: 10, window: 1000 }, // 10 req/s
    EBAY: { requests: 100, window: 60000 }, // 100 req/min
    SHOPEE: { requests: 100, window: 60000 }, // 100 req/min
    ALIEXPRESS: { requests: 50, window: 60000 }, // 50 req/min
  };

  /**
   * 同步商品数据 - 从平台API获取商品信息
   * @param config 平台API配置
   * @param options 同步选项（包含五元组追踪信息）
   * @returns 同步结果
   */
  static async syncProducts(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<ProductSyncResult[]> {
    const { tenantId, shopId, traceId, businessType } = options;
    
    logger.info(`[PlatformApiService] Starting product sync`, {
      platform: config.platform,
      tenantId,
      shopId,
      traceId,
      businessType,
    });

    try {
      switch (config.platform) {
        case 'AMAZON':
          return await this.syncAmazonProducts(config, options);
        case 'EBAY':
          return await this.syncEbayProducts(config, options);
        case 'SHOPEE':
          return await this.syncShopeeProducts(config, options);
        case 'ALIEXPRESS':
          return await this.syncAliexpressProducts(config, options);
        default:
          throw new Error(`Unsupported platform: ${config.platform}`);
      }
    } catch (error: any) {
      logger.error(`[PlatformApiService] Product sync failed`, {
        platform: config.platform,
        tenantId,
        shopId,
        traceId,
        error: error.message,
      });
      throw error;
    }
  }

  /**
   * 同步订单数据 - 从平台API获取订单信息
   * @param config 平台API配置
   * @param options 同步选项（包含五元组追踪信息）
   * @returns 同步结果
   */
  static async syncOrders(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<OrderSyncResult[]> {
    const { tenantId, shopId, traceId, businessType } = options;
    
    logger.info(`[PlatformApiService] Starting order sync`, {
      platform: config.platform,
      tenantId,
      shopId,
      traceId,
      businessType,
    });

    try {
      switch (config.platform) {
        case 'AMAZON':
          return await this.syncAmazonOrders(config, options);
        case 'EBAY':
          return await this.syncEbayOrders(config, options);
        case 'SHOPEE':
          return await this.syncShopeeOrders(config, options);
        case 'ALIEXPRESS':
          return await this.syncAliexpressOrders(config, options);
        default:
          throw new Error(`Unsupported platform: ${config.platform}`);
      }
    } catch (error: any) {
      logger.error(`[PlatformApiService] Order sync failed`, {
        platform: config.platform,
        tenantId,
        shopId,
        traceId,
        error: error.message,
      });
      throw error;
    }
  }

  /**
   * 更新商品库存 - 通过平台API更新库存
   * @param config 平台API配置
   * @param sku SKU编码
   * @param quantity 库存数量
   * @param options 同步选项（包含五元组追踪信息）
   */
  static async updateInventory(
    config: PlatformApiConfig,
    sku: string,
    quantity: number,
    options: SyncOptions
  ): Promise<void> {
    const { tenantId, shopId, traceId, businessType } = options;
    
    logger.info(`[PlatformApiService] Updating inventory`, {
      platform: config.platform,
      sku,
      quantity,
      tenantId,
      shopId,
      traceId,
      businessType,
    });

    // 实际实现需调用各平台API
    // 此处为框架代码，具体实现根据平台API文档补充
    throw new Error('Not implemented - requires platform-specific API integration');
  }

  // ==================== Private Methods ====================

  private static async syncAmazonProducts(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<ProductSyncResult[]> {
    // TODO: 实现Amazon SP-API商品同步
    // 参考: https://developer-docs.amazon.com/sp-api/docs
    logger.info('[PlatformApiService] Amazon product sync - placeholder');
    return [];
  }

  private static async syncAmazonOrders(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<OrderSyncResult[]> {
    // TODO: 实现Amazon SP-API订单同步
    logger.info('[PlatformApiService] Amazon order sync - placeholder');
    return [];
  }

  private static async syncEbayProducts(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<ProductSyncResult[]> {
    const { tenantId, shopId, traceId, businessType, startDate, endDate, limit = 50 } = options;
    
    logger.info('[PlatformApiService] eBay product sync started', {
      tenantId,
      shopId,
      traceId,
      businessType,
      startDate,
      endDate,
      limit,
    });

    try {
      if (!config.accessToken) {
        throw new Error('eBay API requires accessToken');
      }

      const endpoint = this.API_ENDPOINTS.EBAY;
      const results: ProductSyncResult[] = [];

      const filterParams = new URLSearchParams();
      if (startDate) {
        filterParams.append('filter', `lastModifiedDate:[${startDate.toISOString()}..]`);
      }
      if (limit) {
        filterParams.append('limit', String(limit));
      }

      const response = await fetch(`${endpoint}/inventory/v1/inventory_item?${filterParams.toString()}`, {
        method: 'GET',
        headers: {
          'Authorization': `Bearer ${config.accessToken}`,
          'Content-Type': 'application/json',
          'X-EBAY-C-MARKETPLACE-ID': config.marketplaceId || 'EBAY_US',
        },
      });

      if (!response.ok) {
        const errorText = await response.text();
        throw new Error(`eBay API error: ${response.status} - ${errorText}`);
      }

      const data = await response.json();
      const items = data.inventoryItems || [];

      for (const item of items) {
        try {
          const product: ProductSyncResult = {
            platformProductId: item.sku || item.inventoryItemIds?.[0] || '',
            title: item.product?.title || '',
            price: parseFloat(item.product?.aspects?.price?.[0] || '0'),
            currency: item.product?.aspects?.currency?.[0] || 'USD',
            stock: item.availability?.quantity || 0,
            status: item.availability?.shipToLocationAvailability?.quantity > 0 ? 'ACTIVE' : 'INACTIVE',
            syncedAt: new Date(),
          };
          results.push(product);
        } catch (parseError: any) {
          logger.warn('[PlatformApiService] Failed to parse eBay product item', {
            tenantId,
            shopId,
            traceId,
            error: parseError.message,
            item: JSON.stringify(item).substring(0, 200),
          });
        }
      }

      logger.info('[PlatformApiService] eBay product sync completed', {
        tenantId,
        shopId,
        traceId,
        resultCount: results.length,
      });

      return results;
    } catch (error: any) {
      logger.error('[PlatformApiService] eBay product sync failed', {
        tenantId,
        shopId,
        traceId,
        error: error.message,
        stack: error.stack,
      });
      throw error;
    }
  }

  private static async syncEbayOrders(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<OrderSyncResult[]> {
    const { tenantId, shopId, traceId, businessType, startDate, endDate, limit = 50 } = options;
    
    logger.info('[PlatformApiService] eBay order sync started', {
      tenantId,
      shopId,
      traceId,
      businessType,
      startDate,
      endDate,
      limit,
    });

    try {
      if (!config.accessToken) {
        throw new Error('eBay API requires accessToken');
      }

      const endpoint = this.API_ENDPOINTS.EBAY;
      const results: OrderSyncResult[] = [];

      const filterParams = new URLSearchParams();
      if (startDate) {
        filterParams.append('filter', `creationDate:[${startDate.toISOString()}..]`);
      }
      if (endDate) {
        filterParams.append('filter', `creationDate:[..${endDate.toISOString()}]`);
      }
      if (limit) {
        filterParams.append('limit', String(limit));
      }

      const response = await fetch(`${endpoint}/fulfillment/v1/order?${filterParams.toString()}`, {
        method: 'GET',
        headers: {
          'Authorization': `Bearer ${config.accessToken}`,
          'Content-Type': 'application/json',
        },
      });

      if (!response.ok) {
        const errorText = await response.text();
        throw new Error(`eBay API error: ${response.status} - ${errorText}`);
      }

      const data = await response.json();
      const orders = data.members || [];

      for (const order of orders) {
        try {
          const orderItems = (order.lineItems || []).map((item: any) => ({
            sku: item.sku || item.lineItemId || '',
            quantity: item.quantity || 1,
            unitPrice: parseFloat(item.lineItemCost?.value || '0'),
          }));

          const orderResult: OrderSyncResult = {
            platformOrderId: order.orderId || order.legacyOrderId || '',
            status: order.orderFulfillmentStatus || 'IN_PROGRESS',
            totalAmount: parseFloat(order.pricingSummary?.total?.value || '0'),
            currency: order.pricingSummary?.total?.currency || 'USD',
            items: orderItems,
            syncedAt: new Date(),
          };
          results.push(orderResult);
        } catch (parseError: any) {
          logger.warn('[PlatformApiService] Failed to parse eBay order', {
            tenantId,
            shopId,
            traceId,
            error: parseError.message,
            orderId: order.orderId,
          });
        }
      }

      logger.info('[PlatformApiService] eBay order sync completed', {
        tenantId,
        shopId,
        traceId,
        resultCount: results.length,
      });

      return results;
    } catch (error: any) {
      logger.error('[PlatformApiService] eBay order sync failed', {
        tenantId,
        shopId,
        traceId,
        error: error.message,
        stack: error.stack,
      });
      throw error;
    }
  }

  private static async syncShopeeProducts(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<ProductSyncResult[]> {
    const { tenantId, shopId, traceId, businessType, limit = 50, startDate } = options;
    
    logger.info('[PlatformApiService] Shopee product sync started', {
      tenantId,
      shopId,
      traceId,
      businessType,
      limit,
      startDate,
    });

    try {
      if (!config.apiKey || !config.apiSecret) {
        throw new Error('Shopee API requires apiKey and apiSecret');
      }

      const endpoint = this.API_ENDPOINTS.SHOPEE;
      const results: ProductSyncResult[] = [];
      const timestamp = Math.floor(Date.now() / 1000);
      const partnerId = parseInt(config.apiKey, 10);
      const shopIdNum = parseInt(shopId, 10);

      const path = '/api/v2/product/get_item_list';
      const accessToken = config.accessToken || '';
      
      const signBase = `${partnerId}${path}${timestamp}${accessToken}${shopIdNum}`;
      const sign = await this.generateShopeeSign(config.apiSecret, signBase);

      const queryParams = new URLSearchParams({
        partner_id: String(partnerId),
        timestamp: String(timestamp),
        access_token: accessToken,
        shop_id: String(shopIdNum),
        sign: sign,
        page_size: String(Math.min(limit, 100)),
      });

      if (startDate) {
        const updateTimeFrom = Math.floor(startDate.getTime() / 1000);
        queryParams.append('update_time_from', String(updateTimeFrom));
      }

      const response = await fetch(`${endpoint}${path}?${queryParams.toString()}`, {
        method: 'GET',
        headers: {
          'Content-Type': 'application/json',
        },
      });

      if (!response.ok) {
        const errorText = await response.text();
        throw new Error(`Shopee API error: ${response.status} - ${errorText}`);
      }

      const data = await response.json();
      
      if (data.error) {
        throw new Error(`Shopee API error: ${data.error} - ${data.message || data.msg}`);
      }

      const items = data.response?.item_list || [];

      for (const item of items) {
        try {
          const product: ProductSyncResult = {
            platformProductId: String(item.item_id || ''),
            title: item.item_name || '',
            price: parseFloat(item.price_info?.[0]?.current_price || '0'),
            currency: item.currency || 'SGD',
            stock: item.stock_info?.[0]?.current_stock || 0,
            status: item.item_status === 'NORMAL' ? 'ACTIVE' : 'INACTIVE',
            syncedAt: new Date(),
          };
          results.push(product);
        } catch (parseError: any) {
          logger.warn('[PlatformApiService] Failed to parse Shopee product item', {
            tenantId,
            shopId,
            traceId,
            error: parseError.message,
            itemId: item.item_id,
          });
        }
      }

      logger.info('[PlatformApiService] Shopee product sync completed', {
        tenantId,
        shopId,
        traceId,
        resultCount: results.length,
      });

      return results;
    } catch (error: any) {
      logger.error('[PlatformApiService] Shopee product sync failed', {
        tenantId,
        shopId,
        traceId,
        error: error.message,
        stack: error.stack,
      });
      throw error;
    }
  }

  private static async syncShopeeOrders(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<OrderSyncResult[]> {
    const { tenantId, shopId, traceId, businessType, startDate, endDate, limit = 50 } = options;
    
    logger.info('[PlatformApiService] Shopee order sync started', {
      tenantId,
      shopId,
      traceId,
      businessType,
      startDate,
      endDate,
      limit,
    });

    try {
      if (!config.apiKey || !config.apiSecret) {
        throw new Error('Shopee API requires apiKey and apiSecret');
      }

      const endpoint = this.API_ENDPOINTS.SHOPEE;
      const results: OrderSyncResult[] = [];
      const timestamp = Math.floor(Date.now() / 1000);
      const partnerId = parseInt(config.apiKey, 10);
      const shopIdNum = parseInt(shopId, 10);

      const path = '/api/v2/order/get_order_list';
      const accessToken = config.accessToken || '';
      
      const signBase = `${partnerId}${path}${timestamp}${accessToken}${shopIdNum}`;
      const sign = await this.generateShopeeSign(config.apiSecret, signBase);

      const queryParams = new URLSearchParams({
        partner_id: String(partnerId),
        timestamp: String(timestamp),
        access_token: accessToken,
        shop_id: String(shopIdNum),
        sign: sign,
        page_size: String(Math.min(limit, 100)),
        time_range_field: 'create_time',
        order_status: 'ALL',
      });

      if (startDate) {
        queryParams.append('time_from', String(Math.floor(startDate.getTime() / 1000)));
      }
      if (endDate) {
        queryParams.append('time_to', String(Math.floor(endDate.getTime() / 1000)));
      }

      const response = await fetch(`${endpoint}${path}?${queryParams.toString()}`, {
        method: 'GET',
        headers: {
          'Content-Type': 'application/json',
        },
      });

      if (!response.ok) {
        const errorText = await response.text();
        throw new Error(`Shopee API error: ${response.status} - ${errorText}`);
      }

      const data = await response.json();
      
      if (data.error) {
        throw new Error(`Shopee API error: ${data.error} - ${data.message || data.msg}`);
      }

      const orderSnList = data.response?.order_list || [];

      for (const orderSn of orderSnList) {
        try {
          const orderDetail = await this.fetchShopeeOrderDetail(
            endpoint,
            partnerId,
            config.apiSecret,
            accessToken,
            shopIdNum,
            orderSn.order_sn
          );

          if (orderDetail) {
            const orderItems = (orderDetail.item_list || []).map((item: any) => ({
              sku: item.model_sku || item.item_sku || '',
              quantity: item.model_quantity_purchased || item.quantity_purchased || 1,
              unitPrice: parseFloat(item.model_discounted_price || item.item_price || '0'),
            }));

            const orderResult: OrderSyncResult = {
              platformOrderId: orderDetail.order_sn || '',
              status: orderDetail.order_status || 'PROCESSING',
              totalAmount: parseFloat(orderDetail.total_amount || '0'),
              currency: orderDetail.currency || 'SGD',
              items: orderItems,
              syncedAt: new Date(),
            };
            results.push(orderResult);
          }
        } catch (parseError: any) {
          logger.warn('[PlatformApiService] Failed to parse Shopee order', {
            tenantId,
            shopId,
            traceId,
            error: parseError.message,
            orderSn: orderSn.order_sn,
          });
        }
      }

      logger.info('[PlatformApiService] Shopee order sync completed', {
        tenantId,
        shopId,
        traceId,
        resultCount: results.length,
      });

      return results;
    } catch (error: any) {
      logger.error('[PlatformApiService] Shopee order sync failed', {
        tenantId,
        shopId,
        traceId,
        error: error.message,
        stack: error.stack,
      });
      throw error;
    }
  }

  private static async generateShopeeSign(secret: string, baseString: string): Promise<string> {
    const crypto = await import('crypto');
    return crypto
      .createHmac('sha256', secret)
      .update(baseString)
      .digest('hex');
  }

  private static async fetchShopeeOrderDetail(
    endpoint: string,
    partnerId: number,
    secret: string,
    accessToken: string,
    shopId: number,
    orderSn: string
  ): Promise<any> {
    const timestamp = Math.floor(Date.now() / 1000);
    const path = '/api/v2/order/get_order_detail';
    
    const signBase = `${partnerId}${path}${timestamp}${accessToken}${shopId}`;
    const sign = await this.generateShopeeSign(secret, signBase);

    const queryParams = new URLSearchParams({
      partner_id: String(partnerId),
      timestamp: String(timestamp),
      access_token: accessToken,
      shop_id: String(shopId),
      sign: sign,
      order_sn_list: orderSn,
      response_optional_fields: 'order_status,total_amount,currency,item_list',
    });

    const response = await fetch(`${endpoint}${path}?${queryParams.toString()}`, {
      method: 'GET',
      headers: {
        'Content-Type': 'application/json',
      },
    });

    if (!response.ok) {
      return null;
    }

    const data = await response.json();
    if (data.error || !data.response?.order_list?.[0]) {
      return null;
    }

    return data.response.order_list[0];
  }

  private static async syncAliexpressProducts(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<ProductSyncResult[]> {
    // TODO: 实现AliExpress API商品同步
    logger.info('[PlatformApiService] AliExpress product sync - placeholder');
    return [];
  }

  private static async syncAliexpressOrders(
    config: PlatformApiConfig,
    options: SyncOptions
  ): Promise<OrderSyncResult[]> {
    // TODO: 实现AliExpress API订单同步
    logger.info('[PlatformApiService] AliExpress order sync - placeholder');
    return [];
  }

  /**
   * 检查API限流
   * @param platform 平台名称
   */
  private static checkRateLimit(platform: string): boolean {
    const limit = this.RATE_LIMITS[platform as keyof typeof this.RATE_LIMITS];
    if (!limit) return true;
    
    // TODO: 实现基于Redis的分布式限流检查
    return true;
  }

  /**
   * 刷新访问令牌
   * @param config 平台API配置
   */
  private static async refreshAccessToken(config: PlatformApiConfig): Promise<string> {
    // TODO: 实现令牌刷新逻辑
    throw new Error('Token refresh not implemented');
  }
}
