import { Knex } from 'knex';
import db from '../config/database';

export class MerchantDataStatisticsService {
  /**
   * 统计多商户数据
   * @param params 统计参数
   * @param traceInfo 追踪信息
   * @returns 统计数据
   */
  public static async statisticsMerchantData(
    params: {
      merchantId?: string;
      timeRange?: { start: string; end: string };
      metrics?: string[];
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    merchantId: string;
    timestamp: string;
    metrics: Record<string, any>;
    details: Array<{
      metric: string;
      value: number;
      unit: string;
      trend: 'up' | 'down' | 'stable';
    }>;
  }> {
    try {
      // 模拟数据库查询
      const merchantId = params.merchantId || 'all';
      const timestamp = new Date().toISOString();
      
      // 构建统计指标
      const metrics = {
        totalOrders: Math.floor(Math.random() * 1000) + 100,
        totalSales: (Math.random() * 100000 + 10000).toFixed(2),
        averageOrderValue: (Math.random() * 500 + 100).toFixed(2),
        orderCompletionRate: (Math.random() * 30 + 70).toFixed(2),
        activeCustomers: Math.floor(Math.random() * 500) + 100,
        newCustomers: Math.floor(Math.random() * 100) + 20,
      };
      
      const details = Object.entries(metrics).map(([metric, value]) => ({
        metric,
        value: typeof value === 'string' ? parseFloat(value) : value,
        unit: metric.includes('Rate') ? '%' : metric.includes('Sales') || metric.includes('Value') ? '¥' : '',
        trend: ['up', 'down', 'stable'][Math.floor(Math.random() * 3)] as 'up' | 'down' | 'stable',
      }));
      
      return {
        merchantId,
        timestamp,
        metrics,
        details,
      };
    } catch (error) {
      console.error('Error statistics merchant data:', error);
      throw new Error('Failed to statistics merchant data');
    }
  }

  /**
   * 生成商户数据统计报告
   * @param params 报告参数
   * @param traceInfo 追踪信息
   * @returns 报告数据
   */
  public static async generateStatisticsReport(
    params: {
      merchantId?: string;
      timeRange: { start: string; end: string };
      reportType: 'daily' | 'weekly' | 'monthly' | 'quarterly' | 'yearly';
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    reportId: string;
    merchantId: string;
    reportType: string;
    timeRange: { start: string; end: string };
    timestamp: string;
    summary: string;
    metrics: Record<string, any>;
    recommendations: string[];
  }> {
    try {
      const reportId = `REPORT-${Date.now()}`;
      const merchantId = params.merchantId || 'all';
      const timestamp = new Date().toISOString();
      
      // 生成统计数据
      const statistics = await this.statisticsMerchantData(params, traceInfo);
      
      // 生成摘要
      const summary = `商户 ${merchantId} 在 ${params.timeRange.start} 至 ${params.timeRange.end} 期间的${this.getReportTypeName(params.reportType)}统计报告`;
      
      // 生成建议
      const recommendations = [
        '建议优化产品定价策略，提高平均订单价值',
        '建议增加促销活动，吸引更多新客户',
        '建议改进客户服务，提高订单完成率',
        '建议分析销售数据，优化产品结构',
      ];
      
      return {
        reportId,
        merchantId,
        reportType: params.reportType,
        timeRange: params.timeRange,
        timestamp,
        summary,
        metrics: statistics.metrics,
        recommendations,
      };
    } catch (error) {
      console.error('Error generating statistics report:', error);
      throw new Error('Failed to generate statistics report');
    }
  }

  /**
   * 获取商户排名
   * @param params 排名参数
   * @param traceInfo 追踪信息
   * @returns 排名数据
   */
  public static async getMerchantRanking(
    params: {
      metric: 'sales' | 'orders' | 'customers' | 'completionRate';
      limit?: number;
      timeRange: { start: string; end: string };
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    metric: string;
    timeRange: { start: string; end: string };
    timestamp: string;
    rankings: Array<{
      rank: number;
      merchantId: string;
      merchantName: string;
      value: number;
      unit: string;
    }>;
  }> {
    try {
      const limit = params.limit || 10;
      const timestamp = new Date().toISOString();
      
      // 模拟排名数据
      const rankings = Array.from({ length: limit }, (_, index) => ({
        rank: index + 1,
        merchantId: `MERCHANT-${index + 1}`,
        merchantName: `商户${index + 1}`,
        value: Math.floor(Math.random() * 100000) + 1000,
        unit: params.metric === 'completionRate' ? '%' : params.metric === 'customers' || params.metric === 'orders' ? '' : '¥',
      })).sort((a, b) => b.value - a.value);
      
      return {
        metric: params.metric,
        timeRange: params.timeRange,
        timestamp,
        rankings,
      };
    } catch (error) {
      console.error('Error getting merchant ranking:', error);
      throw new Error('Failed to get merchant ranking');
    }
  }

  /**
   * 获取报告类型名称
   * @param reportType 报告类型
   * @returns 报告类型名称
   */
  private static getReportTypeName(reportType: string): string {
    const typeNames = {
      daily: '每日',
      weekly: '每周',
      monthly: '每月',
      quarterly: '季度',
      yearly: '年度',
    };
    return typeNames[reportType as keyof typeof typeNames] || '';
  }
}