import db from '../../config/database';
import { v4 as uuidv4 } from 'uuid';
import { logger } from '../../utils/logger';
// 暂时注释掉，因为AuditService文件不存在
// import { AuditService } from '../core/AuditService';

export interface Inventory {
  id: string;
  tenantId: string;
  shopId: string;
  productId: string;
  skuId: string;
  warehouseId: string;
  quantity: number;
  reservedQuantity: number;
  availableQuantity: number;
  status: 'IN_STOCK' | 'LOW_STOCK' | 'OUT_OF_STOCK';
  lastUpdated: Date;
  createdAt: Date;
}

export interface InventorySync {
  id: string;
  tenantId: string;
  shopId: string;
  platform: string;
  syncType: 'FULL' | 'INCREMENTAL';
  status: 'PENDING' | 'IN_PROGRESS' | 'COMPLETED' | 'FAILED';
  totalItems: number;
  syncedItems: number;
  failedItems: number;
  startedAt: Date;
  completedAt: Date;
  createdAt: Date;
}

export interface InventoryForecast {
  id: string;
  tenantId: string;
  shopId: string;
  productId: string;
  forecastDate: Date;
  predictedQuantity: number;
  confidence: number;
  createdAt: Date;
}

export interface InventoryDistribution {
  id: string;
  tenantId: string;
  shopId: string;
  productId: string;
  warehouseId: string;
  allocatedQuantity: number;
  priority: number;
  createdAt: Date;
}

export class InventoryService {
  private static readonly TABLE_INVENTORY = 'cf_inventory';
  private static readonly TABLE_INVENTORY_SYNC = 'cf_inventory_syncs';
  private static readonly TABLE_INVENTORY_FORECAST = 'cf_inventory_forecasts';
  private static readonly TABLE_INVENTORY_DISTRIBUTION = 'cf_inventory_distributions';

  // ==================== 基础库存管理 ====================

  static async createInventory(inventoryData: Partial<Inventory>): Promise<Inventory> {
    const id = uuidv4();
    const availableQuantity = inventoryData.quantity || 0 - (inventoryData.reservedQuantity || 0);
    const status = this.calculateInventoryStatus(availableQuantity);

    await db(this.TABLE_INVENTORY).insert({
      id,
      ...inventoryData,
      availableQuantity,
      status,
      lastUpdated: new Date(),
      created_at: new Date()
    });
    return (await this.getInventoryById(id))!;
  }

  static async getInventoryById(id: string): Promise<Inventory | null> {
    return await db(this.TABLE_INVENTORY).where({ id }).first();
  }

  static async getInventoryByProduct(productId: string, skuId?: string): Promise<Inventory | null> {
    let query = db(this.TABLE_INVENTORY).where({ productId });
    if (skuId) {
      query = query.where({ skuId });
    }
    return await query.first();
  }

  static async updateInventoryQuantity(id: string, quantity: number): Promise<Inventory | null> {
    const inventory = await this.getInventoryById(id);
    if (!inventory) return null;

    const availableQuantity = quantity - inventory.reservedQuantity;
    const status = this.calculateInventoryStatus(availableQuantity);

    await db(this.TABLE_INVENTORY).where({ id }).update({
      quantity,
      availableQuantity,
      status,
      lastUpdated: new Date()
    });
    return await this.getInventoryById(id);
  }

  static async reserveInventory(id: string, quantity: number): Promise<Inventory | null> {
    const inventory = await this.getInventoryById(id);
    if (!inventory) return null;

    if (inventory.availableQuantity < quantity) {
      throw new Error('Insufficient inventory');
    }

    const reservedQuantity = inventory.reservedQuantity + quantity;
    const availableQuantity = inventory.quantity - reservedQuantity;
    const status = this.calculateInventoryStatus(availableQuantity);

    await db(this.TABLE_INVENTORY).where({ id }).update({
      reservedQuantity,
      availableQuantity,
      status,
      lastUpdated: new Date()
    });
    return await this.getInventoryById(id);
  }

  static async releaseInventory(id: string, quantity: number): Promise<Inventory | null> {
    const inventory = await this.getInventoryById(id);
    if (!inventory) return null;

    if (inventory.reservedQuantity < quantity) {
      throw new Error('Insufficient reserved inventory');
    }

    const reservedQuantity = inventory.reservedQuantity - quantity;
    const availableQuantity = inventory.quantity - reservedQuantity;
    const status = this.calculateInventoryStatus(availableQuantity);

    await db(this.TABLE_INVENTORY).where({ id }).update({
      reservedQuantity,
      availableQuantity,
      status,
      lastUpdated: new Date()
    });
    return await this.getInventoryById(id);
  }

  static async listInventory(tenantId: string, shopId: string, filters?: any): Promise<Inventory[]> {
    let query = db(this.TABLE_INVENTORY).where({ tenantId, shopId });

    if (filters) {
      if (filters.status) query = query.where({ status: filters.status });
      if (filters.warehouseId) query = query.where({ warehouseId: filters.warehouseId });
      if (filters.minQuantity !== undefined) query = query.where('quantity', '>=', filters.minQuantity);
      if (filters.maxQuantity !== undefined) query = query.where('quantity', '<=', filters.maxQuantity);
    }

    return await query.orderBy('lastUpdated', 'desc');
  }

  // ==================== 库存热力图 ====================

  static async getInventoryHotmap(tenantId: string): Promise<any> {
    // 模拟实现：返回全球库存分布热力图数据
    return {
      data: [
        {
          country: 'China',
          quantity: 10000,
          percentage: 40
        },
        {
          country: 'United States',
          quantity: 7500,
          percentage: 30
        },
        {
          country: 'Germany',
          quantity: 2500,
          percentage: 10
        },
        {
          country: 'Japan',
          quantity: 2000,
          percentage: 8
        },
        {
          country: 'Other',
          quantity: 3000,
          percentage: 12
        }
      ],
      total: 25000
    };
  }

  // ==================== 库存同步 ====================

  static async createInventorySync(syncData: Partial<InventorySync>): Promise<InventorySync> {
    const id = uuidv4();
    await db(this.TABLE_INVENTORY_SYNC).insert({
      id,
      ...syncData,
      startedAt: new Date(),
      created_at: new Date()
    });
    return (await this.getInventorySyncById(id))!;
  }

  static async getInventorySyncById(id: string): Promise<InventorySync | null> {
    return await db(this.TABLE_INVENTORY_SYNC).where({ id }).first();
  }

  static async updateInventorySyncStatus(id: string, status: 'IN_PROGRESS' | 'COMPLETED' | 'FAILED', completedAt?: Date): Promise<InventorySync | null> {
    await db(this.TABLE_INVENTORY_SYNC).where({ id }).update({
      status,
      completedAt: completedAt || new Date(),
      updated_at: new Date()
    });
    return await this.getInventorySyncById(id);
  }

  static async syncInventory(tenantId: string, shopId: string, platform: string, syncType: 'FULL' | 'INCREMENTAL'): Promise<InventorySync> {
    const sync = await this.createInventorySync({
      tenantId,
      shopId,
      platform,
      syncType,
      status: 'IN_PROGRESS',
      totalItems: 0,
      syncedItems: 0,
      failedItems: 0
    });

    try {
      // 这里可以实现具体的库存同步逻辑
      // 例如：从平台API获取库存数据并更新本地库存
      const products = await this.getProductsForSync(tenantId, shopId, platform);
      sync.totalItems = products.length;

      for (const product of products) {
        try {
          // 模拟同步过程
          await this.updateProductInventory(tenantId, shopId, product.id, product.skuId, product.quantity);
          sync.syncedItems++;
        } catch (error) {
          logger.error('[InventoryService] Error syncing inventory', { error, productId: product.id });
          sync.failedItems++;
        }
      }

      await this.updateInventorySyncStatus(sync.id, 'COMPLETED');
    } catch (error) {
      logger.error('[InventoryService] Error in sync process', { error });
      await this.updateInventorySyncStatus(sync.id, 'FAILED');
    }

    return sync;
  }

  // ==================== 库存预测 ====================

  static async createInventoryForecast(forecastData: Partial<InventoryForecast>): Promise<InventoryForecast> {
    const id = uuidv4();
    await db(this.TABLE_INVENTORY_FORECAST).insert({
      id,
      ...forecastData,
      created_at: new Date()
    });
    return (await this.getInventoryForecastById(id))!;
  }

  static async getInventoryForecastById(id: string): Promise<InventoryForecast | null> {
    return await db(this.TABLE_INVENTORY_FORECAST).where({ id }).first();
  }

  static async getInventoryForecastByProduct(productId: string, forecastDate: Date): Promise<InventoryForecast | null> {
    return await db(this.TABLE_INVENTORY_FORECAST)
      .where({ productId })
      .where('forecastDate', '=', forecastDate)
      .first();
  }

  static async forecastInventory(tenantId: string, shopId: string, productId: string, days: number): Promise<InventoryForecast[]> {
    const forecasts: InventoryForecast[] = [];

    for (let i = 1; i <= days; i++) {
      const forecastDate = new Date();
      forecastDate.setDate(forecastDate.getDate() + i);

      // 这里可以实现具体的库存预测逻辑
      // 例如：基于历史销售数据和趋势进行预测
      const baseInventory = await this.getInventoryByProduct(productId);
      const predictedQuantity = baseInventory ? baseInventory.quantity * (1 - i * 0.1) : 0; // 简单的线性预测

      const forecast = await this.createInventoryForecast({
        tenantId,
        shopId,
        productId,
        forecastDate,
        predictedQuantity,
        confidence: 0.7 // 模拟70%的置信度
      });

      forecasts.push(forecast);
    }

    return forecasts;
  }

  // ==================== 库存分配 ====================

  static async createInventoryDistribution(distributionData: Partial<InventoryDistribution>): Promise<InventoryDistribution> {
    const id = uuidv4();
    await db(this.TABLE_INVENTORY_DISTRIBUTION).insert({
      id,
      ...distributionData,
      created_at: new Date()
    });
    return (await this.getInventoryDistributionById(id))!;
  }

  static async getInventoryDistributionById(id: string): Promise<InventoryDistribution | null> {
    return await db(this.TABLE_INVENTORY_DISTRIBUTION).where({ id }).first();
  }

  static async distributeInventory(tenantId: string, shopId: string, productId: string, distributions: Array<{
    warehouseId: string;
    quantity: number;
    priority: number;
  }>): Promise<InventoryDistribution[]> {
    const createdDistributions: InventoryDistribution[] = [];

    for (const distribution of distributions) {
      const createdDistribution = await this.createInventoryDistribution({
        tenantId,
        shopId,
        productId,
        warehouseId: distribution.warehouseId,
        allocatedQuantity: distribution.quantity,
        priority: distribution.priority
      });
      createdDistributions.push(createdDistribution);
    }

    return createdDistributions;
  }

  // ==================== 辅助方法 ====================

  private static calculateInventoryStatus(availableQuantity: number): 'IN_STOCK' | 'LOW_STOCK' | 'OUT_OF_STOCK' {
    if (availableQuantity <= 0) {
      return 'OUT_OF_STOCK';
    } else if (availableQuantity < 10) {
      return 'LOW_STOCK';
    } else {
      return 'IN_STOCK';
    }
  }

  private static async getProductsForSync(tenantId: string, shopId: string, platform: string): Promise<Array<{
    id: string;
    skuId: string;
    quantity: number;
  }>> {
    // 模拟从平台获取产品数据
    return [
      { id: '1', skuId: 'SKU1', quantity: 100 },
      { id: '2', skuId: 'SKU2', quantity: 50 },
      { id: '3', skuId: 'SKU3', quantity: 0 }
    ];
  }

  private static async updateProductInventory(tenantId: string, shopId: string, productId: string, skuId: string, quantity: number): Promise<void> {
    const existingInventory = await this.getInventoryByProduct(productId, skuId);
    if (existingInventory) {
      await this.updateInventoryQuantity(existingInventory.id, quantity);
    } else {
      await this.createInventory({
        tenantId,
        shopId,
        productId,
        skuId,
        warehouseId: 'default',
        quantity,
        reservedQuantity: 0
      });
    }
  }

  // ==================== 额外方法 ====================

  static async updateStock(tenantId: string, productId: string, quantity: number): Promise<Inventory | null> {
    const inventory = await this.getInventoryByProduct(productId);
    if (!inventory) return null;
    return await this.updateInventoryQuantity(inventory.id, quantity);
  }

  static async getStock(tenantId: string, skuId: string, warehouseId?: string): Promise<Inventory | null> {
    let query = db(this.TABLE_INVENTORY).where({ tenantId, skuId });
    if (warehouseId) {
      query = query.where({ warehouseId });
    }
    return await query.first();
  }

  static async lockStock(tenantId: string, skuId: string, quantity: number, warehouseId?: string): Promise<boolean> {
    const inventory = await this.getStock(tenantId, skuId, warehouseId);
    if (!inventory) return false;
    
    try {
      await this.reserveInventory(inventory.id, quantity);
      return true;
    } catch (error) {
      logger.error('[InventoryService] Error locking stock', { error, skuId, quantity });
      return false;
    }
  }

  static async deductStock(tenantId: string, skuId: string, quantity: number, warehouseId?: string): Promise<boolean> {
    const inventory = await this.getStock(tenantId, skuId, warehouseId);
    if (!inventory) return false;
    
    try {
      const newQuantity = inventory.quantity - quantity;
      if (newQuantity < 0) return false;
      
      await this.updateInventoryQuantity(inventory.id, newQuantity);
      return true;
    } catch (error) {
      logger.error('[InventoryService] Error deducting stock', { error, skuId, quantity });
      return false;
    }
  }

  static async releaseStock(tenantId: string, skuId: string, quantity: number, warehouseId?: string): Promise<boolean> {
    const inventory = await this.getStock(tenantId, skuId, warehouseId);
    if (!inventory) return false;
    
    try {
      await this.releaseInventory(inventory.id, quantity);
      return true;
    } catch (error) {
      logger.error('[InventoryService] Error releasing stock', { error, skuId, quantity });
      return false;
    }
  }

  static async adjustStock(tenantId: string, skuId: string, quantity: number, warehouseId?: string): Promise<boolean> {
    const inventory = await this.getStock(tenantId, skuId, warehouseId);
    if (!inventory) return false;
    
    try {
      const newQuantity = inventory.quantity + quantity;
      if (newQuantity < 0) return false;
      
      await this.updateInventoryQuantity(inventory.id, newQuantity);
      return true;
    } catch (error) {
      logger.error('[InventoryService] Error adjusting stock', { error, skuId, quantity });
      return false;
    }
  }
}


