import { Injectable, OnModuleDestroy, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import Redis from 'ioredis';

@Injectable()
export class RedisService implements OnModuleDestroy {
  private readonly logger = new Logger(RedisService.name);
  private readonly client: Redis;

  constructor(private readonly configService: ConfigService) {
    const host = this.configService.get<string>('REDIS_HOST') || 'localhost';
    const port = this.configService.get<number>('REDIS_PORT') || 6379;
    const password = this.configService.get<string>('REDIS_PASSWORD');
    const db = this.configService.get<number>('REDIS_DB') || 1;

    this.client = new Redis({
      host,
      port,
      password: password || undefined,
      db,
    });

    this.client.on('connect', () => {
      this.logger.log(`Connected to Redis at ${host}:${port}, DB: ${db}`);
    });

    this.client.on('error', (err) => {
      this.logger.error('Redis connection error:', err);
    });
  }

  async onModuleDestroy() {
    await this.client.quit();
    this.logger.log('Redis connection closed');
  }

  getClient(): Redis {
    return this.client;
  }

  async get(key: string): Promise<string | null> {
    return this.client.get(key);
  }

  async set(key: string, value: string, ttlSeconds?: number): Promise<void> {
    if (ttlSeconds) {
      await this.client.setex(key, ttlSeconds, value);
    } else {
      await this.client.set(key, value);
    }
  }

  async del(key: string): Promise<void> {
    await this.client.del(key);
  }

  async delByPattern(pattern: string): Promise<number> {
    const keys = await this.client.keys(pattern);
    if (keys.length === 0) {
      return 0;
    }
    return this.client.del(...keys);
  }

  async exists(key: string): Promise<boolean> {
    const result = await this.client.exists(key);
    return result === 1;
  }

  async setJson<T>(key: string, value: T, ttlSeconds?: number): Promise<void> {
    await this.set(key, JSON.stringify(value), ttlSeconds);
  }

  async getJson<T>(key: string): Promise<T | null> {
    const value = await this.get(key);
    if (!value) {
      return null;
    }
    try {
      return JSON.parse(value) as T;
    } catch {
      this.logger.warn(`Failed to parse JSON for key: ${key}`);
      return null;
    }
  }

  async ttl(key: string): Promise<number> {
    return this.client.ttl(key);
  }
}