/**
 * BullMQ / ioredis connection for concierge queues.
 * DigitalOcean Managed Redis (port 25061) requires TLS — use rediss:// or REDIS_TLS=true.
 */
function parseRedisUrl(raw) {
  const url = String(raw || 'redis://127.0.0.1:6379').trim();
  try {
    return new URL(url);
  } catch {
    return null;
  }
}

function shouldUseTls(parsed) {
  if (!parsed) return false;
  const force =
    String(process.env.REDIS_TLS || '').trim().toLowerCase() === '1' ||
    String(process.env.REDIS_TLS || '').trim().toLowerCase() === 'true';
  if (force) return true;
  if (parsed.protocol === 'rediss:') return true;
  if (parsed.port === '25061') return true;
  if (parsed.hostname && parsed.hostname.includes('ondigitalocean.com')) return true;
  return false;
}

/**
 * Options for BullMQ `connection` (ioredis). maxRetriesPerRequest must be null for workers.
 * @returns {import('ioredis').RedisOptions}
 */
function getBullMQConnection() {
  const raw = process.env.REDIS_URL || 'redis://127.0.0.1:6379';
  const parsed = parseRedisUrl(raw);

  const conn = {
    maxRetriesPerRequest: null,
    enableReadyCheck: true,
    retryStrategy(times) {
      return Math.min(times * 300, 8000);
    },
  };

  if (!parsed) {
    return { ...conn, host: '127.0.0.1', port: 6379 };
  }

  Object.assign(conn, {
    host: parsed.hostname,
    port: Number(parsed.port) || 6379,
    username: parsed.username || undefined,
    password: parsed.password ? decodeURIComponent(parsed.password) : undefined,
  });

  if (parsed.pathname && parsed.pathname.length > 1) {
    const db = Number(parsed.pathname.slice(1));
    if (!Number.isNaN(db)) conn.db = db;
  }

  if (shouldUseTls(parsed)) {
    conn.tls = {};
    if (!parsed.port) conn.port = 25061;
  }

  return conn;
}

/**
 * Verify Redis is reachable at startup (workers).
 */
async function verifyRedisConnection() {
  const Redis = require('ioredis');
  const opts = getBullMQConnection();
  const client = new Redis(opts);

  try {
    await client.ping();
    const tlsNote = opts.tls ? ' (TLS)' : '';
    console.log(`[redis] connected: ${opts.host}:${opts.port}${tlsNote}`);
  } catch (err) {
    const hint = opts.tls
      ? ''
      : '\n  Hint: DigitalOcean Managed Redis needs TLS. Set REDIS_TLS=true or use rediss:// in REDIS_URL.';
    throw new Error(`Redis connection failed: ${err.message}${hint}`);
  } finally {
    client.disconnect();
  }
}

module.exports = {
  getBullMQConnection,
  verifyRedisConnection,
  shouldUseTls,
  parseRedisUrl,
};