import { InMemoryHealthCheckAdapter } from './InMemoryHealthCheckAdapter';

describe('InMemoryHealthCheckAdapter', () => {
  let adapter: InMemoryHealthCheckAdapter;

  beforeEach(() => {
    adapter = new InMemoryHealthCheckAdapter();
    adapter.setResponseTime(0); // Speed up tests
  });

  describe('Health Checks', () => {
    it('should return healthy by default', async () => {
      // When
      const result = await adapter.performHealthCheck();

      // Then
      expect(result.healthy).toBe(true);
      expect(adapter.getStatus()).toBe('connected');
    });

    it('should return unhealthy when configured to fail', async () => {
      // Given
      adapter.setShouldFail(true, 'Custom error');

      // When
      const result = await adapter.performHealthCheck();

      // Then
      expect(result.healthy).toBe(false);
      expect(result.error).toBe('Custom error');
    });
  });

  describe('Status Transitions', () => {
    it('should transition to disconnected after 3 consecutive failures', async () => {
      // Given
      adapter.setShouldFail(true);

      // When
      await adapter.performHealthCheck(); // 1
      expect(adapter.getStatus()).toBe('checking'); // Initial state is disconnected, first failure keeps it checking/disconnected
      
      await adapter.performHealthCheck(); // 2
      await adapter.performHealthCheck(); // 3

      // Then
      expect(adapter.getStatus()).toBe('disconnected');
    });

    it('should transition to degraded if reliability is low', async () => {
      // Given
      // We need 5 requests total, and reliability < 0.7
      // 1 success, 4 failures (not consecutive)
      
      await adapter.performHealthCheck(); // Success 1
      
      adapter.setShouldFail(true);
      await adapter.performHealthCheck(); // Failure 1
      adapter.setShouldFail(false);
      await adapter.performHealthCheck(); // Success 2 (resets consecutive)
      adapter.setShouldFail(true);
      await adapter.performHealthCheck(); // Failure 2
      await adapter.performHealthCheck(); // Failure 3
      adapter.setShouldFail(false);
      await adapter.performHealthCheck(); // Success 3 (resets consecutive)
      adapter.setShouldFail(true);
      await adapter.performHealthCheck(); // Failure 4
      await adapter.performHealthCheck(); // Failure 5

      // Then
      expect(adapter.getStatus()).toBe('degraded');
      expect(adapter.getReliability()).toBeLessThan(70);
    });

    it('should recover status after a success', async () => {
      // Given
      adapter.setShouldFail(true);
      await adapter.performHealthCheck();
      await adapter.performHealthCheck();
      await adapter.performHealthCheck();
      expect(adapter.getStatus()).toBe('disconnected');

      // When
      adapter.setShouldFail(false);
      await adapter.performHealthCheck();

      // Then
      expect(adapter.getStatus()).toBe('connected');
      expect(adapter.isAvailable()).toBe(true);
    });
  });

  describe('Metrics', () => {
    it('should track average response time', async () => {
      // Given
      adapter.setResponseTime(10);
      await adapter.performHealthCheck();
      
      adapter.setResponseTime(20);
      await adapter.performHealthCheck();

      // Then
      const health = adapter.getHealth();
      expect(health.averageResponseTime).toBe(15);
      expect(health.totalRequests).toBe(2);
    });
  });

  describe('Maintenance', () => {
    it('should clear state', async () => {
      // Given
      await adapter.performHealthCheck();
      expect(adapter.getHealth().totalRequests).toBe(1);

      // When
      adapter.clear();

      // Then
      expect(adapter.getHealth().totalRequests).toBe(0);
      expect(adapter.getStatus()).toBe('disconnected'); // Initial state
    });
  });
});