import Redis from 'ioredis';
import { config } from '../config';

export class CacheStrategyService {
  private static redisClient: Redis;

  /**
   * 初始化Redis客户端
   */
  private static initializeRedis() {
    if (!this.redisClient) {
      this.redisClient = new Redis({
        host: config.redis.host,
        port: config.redis.port,
        password: config.redis.password,
      });
    }
  }

  /**
   * 分析缓存使用情况
   * @param params 分析参数
   * @param traceInfo 追踪信息
   * @returns 缓存使用分析结果
   */
  public static async analyzeCacheUsage(
    params: {
      timeRange: { start: string; end: string };
      cacheKeys?: string[];
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    timestamp: string;
    timeRange: { start: string; end: string };
    totalCacheKeys: number;
    cacheHitRate: number;
    cacheMissRate: number;
    topAccessedKeys: Array<{
      key: string;
      accessCount: number;
      hitCount: number;
      missCount: number;
      hitRate: number;
    }>;
    recommendations: string[];
  }> {
    try {
      const timestamp = new Date().toISOString();
      
      // 模拟缓存使用分析数据
      const topAccessedKeys = Array.from({ length: 10 }, (_, index) => ({
        key: `product:${index + 1}`,
        accessCount: Math.floor(Math.random() * 10000) + 1000,
        hitCount: Math.floor(Math.random() * 9000) + 900,
        missCount: Math.floor(Math.random() * 1000) + 100,
        hitRate: (Math.random() * 30 + 70).toFixed(2),
      }));
      
      const totalCacheKeys = 1000;
      const cacheHitRate = (Math.random() * 30 + 70).toFixed(2);
      const cacheMissRate = (100 - parseFloat(cacheHitRate)).toFixed(2);
      
      // 生成优化建议
      const recommendations = [
        '增加热门商品的缓存过期时间',
        '实现缓存预热机制，提前加载热门数据',
        '优化缓存键设计，使用更合理的命名规则',
        '考虑使用二级缓存，提高缓存命中率',
        '监控缓存使用情况，及时调整缓存策略',
      ];
      
      return {
        timestamp,
        timeRange: params.timeRange,
        totalCacheKeys,
        cacheHitRate: parseFloat(cacheHitRate),
        cacheMissRate: parseFloat(cacheMissRate),
        topAccessedKeys: topAccessedKeys.map(key => ({
          ...key,
          hitRate: parseFloat(key.hitRate),
        })),
        recommendations,
      };
    } catch (error) {
      console.error('Error analyzing cache usage:', error);
      throw new Error('Failed to analyze cache usage');
    }
  }

  /**
   * 优化缓存策略
   * @param params 缓存策略参数
   * @param traceInfo 追踪信息
   * @returns 缓存策略优化结果
   */
  public static async optimizeCacheStrategy(
    params: {
      cacheKeys: Array<{
        key: string;
        ttl: number;
        priority: 'high' | 'medium' | 'low';
      }>;
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    timestamp: string;
    optimizedKeys: number;
    results: Array<{
      key: string;
      oldTtl: number;
      newTtl: number;
      status: string;
    }>;
  }> {
    try {
      const timestamp = new Date().toISOString();
      const results = [];
      
      for (const keyInfo of params.cacheKeys) {
        // 根据优先级调整TTL
        let newTtl = keyInfo.ttl;
        if (keyInfo.priority === 'high') {
          newTtl = 3600; // 1 hour
        } else if (keyInfo.priority === 'medium') {
          newTtl = 1800; // 30 minutes
        } else if (keyInfo.priority === 'low') {
          newTtl = 600; // 10 minutes
        }
        
        results.push({
          key: keyInfo.key,
          oldTtl: keyInfo.ttl,
          newTtl,
          status: 'success',
        });
      }
      
      return {
        timestamp,
        optimizedKeys: params.cacheKeys.length,
        results,
      };
    } catch (error) {
      console.error('Error optimizing cache strategy:', error);
      throw new Error('Failed to optimize cache strategy');
    }
  }

  /**
   * 实现缓存预热
   * @param params 预热参数
   * @param traceInfo 追踪信息
   * @returns 预热结果
   */
  public static async prewarmCache(
    params: {
      cacheKeys: Array<{
        key: string;
        data: any;
        ttl: number;
      }>;
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    timestamp: string;
    prewarmedKeys: number;
    results: Array<{
      key: string;
      status: 'success' | 'failure';
      message: string;
    }>;
  }> {
    try {
      const timestamp = new Date().toISOString();
      const results = [];
      let prewarmedKeys = 0;
      
      for (const keyInfo of params.cacheKeys) {
        try {
          // 模拟缓存预热
          results.push({
            key: keyInfo.key,
            status: 'success' as 'success',
            message: 'Cache prewarmed successfully',
          });
          prewarmedKeys++;
        } catch (error) {
          results.push({
            key: keyInfo.key,
            status: 'failure' as 'failure',
            message: error.message,
          });
        }
      }
      
      return {
        timestamp,
        prewarmedKeys,
        results,
      };
    } catch (error) {
      console.error('Error prewarming cache:', error);
      throw new Error('Failed to prewarm cache');
    }
  }

  /**
   * 清理过期缓存
   * @param params 清理参数
   * @param traceInfo 追踪信息
   * @returns 清理结果
   */
  public static async cleanExpiredCache(
    params: {
      pattern?: string;
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    timestamp: string;
    cleanedKeys: number;
    pattern: string;
  }> {
    try {
      const timestamp = new Date().toISOString();
      const pattern = params.pattern || '*';
      
      // 模拟清理过期缓存
      const cleanedKeys = Math.floor(Math.random() * 1000) + 100;
      
      return {
        timestamp,
        cleanedKeys,
        pattern,
      };
    } catch (error) {
      console.error('Error cleaning expired cache:', error);
      throw new Error('Failed to clean expired cache');
    }
  }

  /**
   * 获取缓存性能指标
   * @param params 指标参数
   * @param traceInfo 追踪信息
   * @returns 性能指标
   */
  public static async getCacheMetrics(
    params: {
      metrics: string[];
    },
    traceInfo: {
      tenantId: string;
      shopId: string;
      taskId: string;
      traceId: string;
      businessType: 'TOC' | 'TOB';
    }
  ): Promise<{
    timestamp: string;
    metrics: Record<string, any>;
  }> {
    try {
      const timestamp = new Date().toISOString();
      const metrics: Record<string, any> = {};
      
      if (params.metrics.includes('cacheHitRate')) {
        metrics.cacheHitRate = (Math.random() * 30 + 70).toFixed(2);
      }
      if (params.metrics.includes('cacheMissRate')) {
        metrics.cacheMissRate = (Math.random() * 30 + 5).toFixed(2);
      }
      if (params.metrics.includes('averageCacheTime')) {
        metrics.averageCacheTime = (Math.random() * 10 + 1).toFixed(2);
      }
      if (params.metrics.includes('totalCacheSize')) {
        metrics.totalCacheSize = Math.floor(Math.random() * 1000000000) + 100000000;
      }
      if (params.metrics.includes('cacheKeysCount')) {
        metrics.cacheKeysCount = Math.floor(Math.random() * 10000) + 1000;
      }
      
      return {
        timestamp,
        metrics,
      };
    } catch (error) {
      console.error('Error getting cache metrics:', error);
      throw new Error('Failed to get cache metrics');
    }
  }
}
