class CircuitBreaker {
  private failures = 0;
  private lastFailure?: Date;

  async call<T>(fn: () => Promise<T>): Promise<T> {
    if (this.isOpen()) {
      throw new Error('Circuit is open');
    }
    try {
      const result = await fn();
      this.reset();
      return result;
    } catch (error) {
      this.recordFailure();
      throw error;
    }
  }
}

async function withRetry<T>(
  fn: () => Promise<T>,
  maxRetries = 3
): Promise<T> {
  for (let i = 0; i < maxRetries; i++) {
    try {
      return await fn();
    } catch (error) {
      if (i === maxRetries - 1) throw error;
      await sleep(Math.pow(2, i) * 1000); // Exponential backoff
    }
  }
}

app.get('/health', (req, res) => {
  res.json({ status: 'healthy' });
});

app.get('/ready', async (req, res) => {
  const dbHealthy = await checkDatabase();
  const cacheHealthy = await checkCache();

  if (dbHealthy && cacheHealthy) {
    res.json({ status: 'ready' });
  } else {
    res.status(503).json({ status: 'not ready' });
  }
});