// redisSingleton.mjs
// Conexión Singleton a Redis para Authentik (AK)

import { createClient } from 'redis';

class RedisAuthentik {
  static instance = null;

  constructor() {
    if (RedisAuthentik.instance) {
      return RedisAuthentik.instance;
    }

    const url = process.env.AK_REDIS_URL;
    if (!url) {
      throw new Error('Falta AK_REDIS_URL Ej: redis://:pass@host:6379/0');
    }
    if (!/^redis(s)?:\/\//i.test(url)) {
      throw new Error('AK_REDIS_URL inválida: debe comenzar con "redis://" o "rediss://".');
    }

    this.url = url;
    this.client = createClient({
      url: this.url,
      socket: { connectTimeout: 5000 },
    });

    this.client.on('connect',      () => console.log(`[REDIS AK] Conectando a ${this.url}`));
    this.client.on('ready',        () => console.log('[REDIS AK] Conexión lista.'));
    this.client.on('end',          () => console.warn('[REDIS AK] Conexión cerrada.'));
    this.client.on('reconnecting', () => console.warn('[REDIS AK] Reintentando conexión...'));
    this.client.on('error',        (err) => console.error('[REDIS AK] Error:', err?.message || err));

    this._connectingPromise = null;
    RedisAuthentik.instance = this;
  }

  async connect() {
    if (this.client.isOpen) return this.client;
    if (this._connectingPromise) return this._connectingPromise;

    this._connectingPromise = this.client.connect()
      .then(() => this.client)
      .catch((err) => {
        this._connectingPromise = null;
        console.error('[REDIS AK] Falló la conexión inicial:', err?.message || err);
        throw err;
      });

    return this._connectingPromise;
  }

  getClient() {
    return this.client;
  }

  async release() {
    try {
      if (this.client?.isOpen) await this.client.quit();
    } catch (e) {
      console.warn('[REDIS AK] Error al cerrar:', e?.message || e);
    } finally {
      this._connectingPromise = null;
    }
  }
}

// Instancia única
const redisAuthentik = new RedisAuthentik();

// --------------------- Healthcheck ---------------------
async function verificarConexionRedisAuthentik() {
  try {
    console.log(`[REDIS AK] Comprobando accesibilidad a Redis en ${redisAuthentik.url} ...`);
    await redisAuthentik.connect();
    const client = redisAuthentik.getClient();

    const pong = await client.ping();
    const timeArr = await client.sendCommand(['TIME']);
    const serverDate = new Date(Number(timeArr?.[0] || 0) * 1000);

    await client.set('hc:authentik', String(Date.now()), { EX: 10 });

    console.log(`[REDIS AK] Conexión OK. PING=${pong}. Hora Redis:`, serverDate.toISOString());
  } catch (error) {
    console.error('[REDIS AK] Error al conectar:', error?.message || error);
    console.error('[REDIS AK] Revisar AK_REDIS_URL, credenciales, red y firewall.');
  }
}

// Export al estilo de poolSingleton.mjs
export default { redisAuthentik, verificarConexionRedisAuthentik };
export { redisAuthentik, verificarConexionRedisAuthentik };