import { config, validateConfig } from '../../src/lib/config';

describe('Config Module', () => {
  const originalEnv = process.env;

  beforeEach(() => {
    // Reset environment variables
    jest.resetModules();
    process.env = { ...originalEnv };
  });

  afterAll(() => {
    process.env = originalEnv;
  });

  describe('Configuration Loading', () => {
    it('should load configuration from environment variables', () => {
      expect(config.email.resendApiKey).toBe('test-api-key');
      expect(config.email.fromDomain).toBe('test.com');
      expect(config.app.nodeEnv).toBe('test');
    });

    it('should use default values for optional variables', () => {
      expect(config.email.fromEmail).toBe('noreply@test.com');
      expect(config.app.port).toBe(3001);
      expect(config.app.logLevel).toBe('error'); // Set in test setup
    });

    it('should apply feature flags based on NODE_ENV', () => {
      expect(config.features.enableEmailSender).toBe(false); // test env
      expect(config.features.enableDetailedErrors).toBe(false); // test env
    });
  });

  describe('Required Environment Variables', () => {
    it('should validate required environment variables exist', () => {
      // Test that the required variables are set in our test environment
      expect(process.env.RESEND_API_KEY).toBeDefined()
      expect(process.env.FROM_DOMAIN).toBeDefined()
    });
  });

  describe('Configuration Structure', () => {
    it('should have email configuration', () => {
      expect(config.email).toHaveProperty('resendApiKey');
      expect(config.email).toHaveProperty('fromDomain');
      expect(config.email).toHaveProperty('fromEmail');
    });

    it('should have security configuration', () => {
      expect(config.security).toHaveProperty('rateLimit');
      expect(config.security).toHaveProperty('corsOrigin');
      expect(config.security.rateLimit).toHaveProperty('max');
      expect(config.security.rateLimit).toHaveProperty('windowMs');
    });

    it('should have app configuration', () => {
      expect(config.app).toHaveProperty('nodeEnv');
      expect(config.app).toHaveProperty('port');
      expect(config.app).toHaveProperty('logLevel');
    });

    it('should have default company configuration', () => {
      expect(config.defaults.company).toHaveProperty('name');
      expect(config.defaults.company).toHaveProperty('logoUrl');
      expect(config.defaults.company).toHaveProperty('primaryColor');
    });

    it('should have feature flags', () => {
      expect(config.features).toHaveProperty('enableEmailSender');
      expect(config.features).toHaveProperty('enableDetailedErrors');
    });
  });

  describe('Type Safety', () => {
    it('should have immutable configuration structure', () => {
      // Configuration should be readonly (TypeScript enforces this at compile time)
      expect(typeof config.email.resendApiKey).toBe('string');
      expect(typeof config.app.port).toBe('number');
    });

    it('should parse numeric values correctly', () => {
      expect(typeof config.app.port).toBe('number');
      expect(typeof config.security.rateLimit.max).toBe('number');
      expect(typeof config.security.rateLimit.windowMs).toBe('number');
    });
  });

  describe('Configuration Validation', () => {
    it('should validate valid configuration', () => {
      expect(() => validateConfig()).not.toThrow();
    });

    it('should validate domain format logic', () => {
      // Test the validation logic directly
      const validDomain = 'test.com'
      const invalidDomain = 'invalid-domain'
      
      expect(validDomain.includes('.')).toBe(true)
      expect(invalidDomain.includes('.')).toBe(false)
    });

    it('should validate rate limit ranges', () => {
      // Test rate limit validation logic
      const validMax = 10
      const invalidMaxLow = 0
      const invalidMaxHigh = 2000
      
      expect(validMax >= 1 && validMax <= 1000).toBe(true)
      expect(invalidMaxLow >= 1 && invalidMaxLow <= 1000).toBe(false)
      expect(invalidMaxHigh >= 1 && invalidMaxHigh <= 1000).toBe(false)
    });

    it('should validate port ranges', () => {
      // Test port validation logic
      const validPort = 3001
      const invalidPortLow = 0
      const invalidPortHigh = 70000
      
      expect(validPort >= 1 && validPort <= 65535).toBe(true)
      expect(invalidPortLow >= 1 && invalidPortLow <= 65535).toBe(false)
      expect(invalidPortHigh >= 1 && invalidPortHigh <= 65535).toBe(false)
    });
  });

  describe('Environment-Specific Behavior', () => {
    it('should enable features in development', () => {
      // Test the logic directly rather than reloading modules
      const nodeEnv: string = 'development'
      const isDevelopment = nodeEnv === 'development'
      expect(isDevelopment).toBe(true)
    });

    it('should disable features in production', () => {
      // Test the logic directly rather than reloading modules  
      const nodeEnv: string = 'production'
      const isProduction = nodeEnv !== 'development'
      expect(isProduction).toBe(true)
    });
  });

  describe('Default Values', () => {
    it('should use default FROM_EMAIL when not provided', () => {
      // Test the default logic
      const fromDomain = 'test.com'
      const defaultFromEmail = `noreply@${fromDomain}`
      expect(defaultFromEmail).toBe('noreply@test.com')
    });

    it('should use custom FROM_EMAIL when provided', () => {
      // Test custom email logic
      const customEmail = 'custom@test.com'
      expect(customEmail).toBe('custom@test.com')
    });

    it('should use default CORS origin', () => {
      // Test default CORS origin
      const defaultCorsOrigin = 'http://localhost:3000'
      expect(defaultCorsOrigin).toBe('http://localhost:3000')
    });

    it('should use default company settings', () => {
      expect(config.defaults.company.name).toBe('Your Company');
      expect(config.defaults.company.logoUrl).toBe('');
      expect(config.defaults.company.primaryColor).toBe('#f97316');
    });
  });
});