import { createClient } from 'redis';

let redisClient: ReturnType<typeof createClient> | null = null;

export const getRedisClient = async () => {
  if (!redisClient) {
    const redisUrl = process.env.REDIS_URL || 'redis://localhost:6379';
    
    redisClient = createClient({
      url: redisUrl,
      socket: {
        reconnectStrategy: (retries) => Math.min(retries * 50, 1000)
      }
    });

    redisClient.on('error', (err) => {
      console.error('Redis Client Error:', err);
    });

    redisClient.on('connect', () => {
      console.log('Redis Client Connected');
    });

    redisClient.on('ready', () => {
      console.log('Redis Client Ready');
    });

    redisClient.on('end', () => {
      console.log('Redis Client Disconnected');
    });

    await redisClient.connect();
  }

  return redisClient;
};

export const closeRedisConnection = async () => {
  if (redisClient) {
    await redisClient.quit();
    redisClient = null;
  }
};

// Cache utilities
export const cache = {
  async get(key: string) {
    try {
      const client = await getRedisClient();
      const value = await client.get(key);
      return value ? JSON.parse(value) : null;
    } catch (error) {
      console.error('Redis GET error:', error);
      return null;
    }
  },

  async set(key: string, value: unknown, ttlSeconds = 3600) {
    try {
      const client = await getRedisClient();
      await client.setEx(key, ttlSeconds, JSON.stringify(value));
      return true;
    } catch (error) {
      console.error('Redis SET error:', error);
      return false;
    }
  },

  async del(key: string) {
    try {
      const client = await getRedisClient();
      await client.del(key);
      return true;
    } catch (error) {
      console.error('Redis DEL error:', error);
      return false;
    }
  },

  async exists(key: string) {
    try {
      const client = await getRedisClient();
      return await client.exists(key);
    } catch (error) {
      console.error('Redis EXISTS error:', error);
      return false;
    }
  },

  async flush() {
    try {
      const client = await getRedisClient();
      await client.flushAll();
      return true;
    } catch (error) {
      console.error('Redis FLUSH error:', error);
      return false;
    }
  }
};

// Session management
export const session = {
  async create(userId: string, data: unknown, ttlSeconds = 86400) {
    const sessionId = `session:${userId}:${Date.now()}`;
    await cache.set(sessionId, data, ttlSeconds);
    return sessionId;
  },

  async get(sessionId: string) {
    return await cache.get(sessionId);
  },

  async update(sessionId: string, data: unknown, ttlSeconds = 86400) {
    return await cache.set(sessionId, data, ttlSeconds);
  },

  async destroy(sessionId: string) {
    return await cache.del(sessionId);
  }
};

// Analytics caching
export const analyticsCache = {
  async getProjectStats(projectId: number) {
    return await cache.get(`analytics:project:${projectId}`);
  },

  async setProjectStats(projectId: number, stats: unknown, ttlSeconds = 300) {
    return await cache.set(`analytics:project:${projectId}`, stats, ttlSeconds);
  },

  async getOverallStats() {
    return await cache.get('analytics:overall');
  },

  async setOverallStats(stats: unknown, ttlSeconds = 600) {
    return await cache.set('analytics:overall', stats, ttlSeconds);
  },

  async invalidateProject(projectId: number) {
    await cache.del(`analytics:project:${projectId}`);
    await cache.del('analytics:overall');
  },

  async clearAll() {
    try {
      const client = await getRedisClient();
      // Clear all analytics-related keys
      const keys = await client.keys('analytics:*');
      if (keys.length > 0) {
        await client.del(keys);
      }
    } catch (error) {
      console.error('Error clearing analytics cache:', error);
    }
  }
};