import {
  getMailgunConfig,
  isMailgunConfigured,
  isDevelopmentMode,
} from '../mailgun.config';

// Mock environment utilities
jest.mock('../../utils/env', () => ({
  getEnvVar: jest.fn(),
  isProduction: jest.fn(),
}));

describe('Mailgun Configuration', () => {
  let mockGetEnvVar: jest.MockedFunction<any>;
  let mockIsProduction: jest.MockedFunction<any>;

  beforeEach(() => {
    jest.clearAllMocks();

    // Get mocked functions
    const envUtils = require('../../utils/env');
    mockGetEnvVar = envUtils.getEnvVar;
    mockIsProduction = envUtils.isProduction;

    // Default mock implementations
    mockIsProduction.mockReturnValue(false);
  });

  describe('getMailgunConfig', () => {
    test('should return config with all environment variables set', () => {
      mockGetEnvVar
        .mockReturnValueOnce('test-api-key') // VITE_MAILGUN_API_KEY
        .mockReturnValueOnce('test.domain.com') // VITE_MAILGUN_DOMAIN
        .mockReturnValueOnce('https://api.mailgun.net/v3') // VITE_MAILGUN_BASE_URL
        .mockReturnValueOnce('Test App') // VITE_MAILGUN_FROM_NAME
        .mockReturnValueOnce('noreply@test.com'); // VITE_MAILGUN_FROM_EMAIL

      const config = getMailgunConfig();

      expect(config).toEqual({
        apiKey: 'test-api-key',
        domain: 'test.domain.com',
        baseUrl: 'https://api.mailgun.net/v3',
        fromName: 'Test App',
        fromEmail: 'noreply@test.com',
      });

      expect(mockGetEnvVar).toHaveBeenCalledTimes(5);
      expect(mockGetEnvVar).toHaveBeenNthCalledWith(1, 'VITE_MAILGUN_API_KEY');
      expect(mockGetEnvVar).toHaveBeenNthCalledWith(2, 'VITE_MAILGUN_DOMAIN');
      expect(mockGetEnvVar).toHaveBeenNthCalledWith(
        3,
        'VITE_MAILGUN_BASE_URL',
        'https://api.mailgun.net/v3'
      );
      expect(mockGetEnvVar).toHaveBeenNthCalledWith(
        4,
        'VITE_MAILGUN_FROM_NAME',
        'Medication Reminder'
      );
      expect(mockGetEnvVar).toHaveBeenNthCalledWith(
        5,
        'VITE_MAILGUN_FROM_EMAIL'
      );
    });

    test('should use default values for optional config', () => {
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        if (key === 'VITE_MAILGUN_API_KEY') return 'test-api-key';
        if (key === 'VITE_MAILGUN_DOMAIN') return 'test.domain.com';
        if (key === 'VITE_MAILGUN_FROM_EMAIL') return 'noreply@test.com';
        return defaultValue;
      });

      const config = getMailgunConfig();

      expect(config.baseUrl).toBe('https://api.mailgun.net/v3');
      expect(config.fromName).toBe('Medication Reminder');
    });

    test('should handle missing environment variables gracefully', () => {
      mockGetEnvVar.mockImplementation(
        (_key: string, defaultValue?: string) => defaultValue
      );

      const config = getMailgunConfig();

      expect(config).toEqual({
        apiKey: undefined,
        domain: undefined,
        baseUrl: 'https://api.mailgun.net/v3',
        fromName: 'Medication Reminder',
        fromEmail: undefined,
      });
    });
  });

  describe('isMailgunConfigured', () => {
    test('should return true when all required config is present', () => {
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        switch (key) {
          case 'VITE_MAILGUN_API_KEY':
            return 'test-api-key';
          case 'VITE_MAILGUN_DOMAIN':
            return 'test.domain.com';
          case 'VITE_MAILGUN_FROM_EMAIL':
            return 'noreply@test.com';
          case 'VITE_MAILGUN_BASE_URL':
            return 'https://api.mailgun.net/v3';
          case 'VITE_MAILGUN_FROM_NAME':
            return 'Test App';
          default:
            return defaultValue;
        }
      });

      expect(isMailgunConfigured()).toBe(true);
    });

    test('should return false when apiKey is missing', () => {
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        switch (key) {
          case 'VITE_MAILGUN_API_KEY':
            return undefined;
          case 'VITE_MAILGUN_DOMAIN':
            return 'test.domain.com';
          case 'VITE_MAILGUN_FROM_EMAIL':
            return 'noreply@test.com';
          case 'VITE_MAILGUN_BASE_URL':
            return 'https://api.mailgun.net/v3';
          case 'VITE_MAILGUN_FROM_NAME':
            return 'Test App';
          default:
            return defaultValue;
        }
      });

      expect(isMailgunConfigured()).toBe(false);
    });

    test('should return false when domain is missing', () => {
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        switch (key) {
          case 'VITE_MAILGUN_API_KEY':
            return 'test-api-key';
          case 'VITE_MAILGUN_DOMAIN':
            return undefined;
          case 'VITE_MAILGUN_FROM_EMAIL':
            return 'noreply@test.com';
          case 'VITE_MAILGUN_BASE_URL':
            return 'https://api.mailgun.net/v3';
          case 'VITE_MAILGUN_FROM_NAME':
            return 'Test App';
          default:
            return defaultValue;
        }
      });

      expect(isMailgunConfigured()).toBe(false);
    });

    test('should return false when fromEmail is missing', () => {
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        switch (key) {
          case 'VITE_MAILGUN_API_KEY':
            return 'test-api-key';
          case 'VITE_MAILGUN_DOMAIN':
            return 'test.domain.com';
          case 'VITE_MAILGUN_FROM_EMAIL':
            return undefined;
          case 'VITE_MAILGUN_BASE_URL':
            return 'https://api.mailgun.net/v3';
          case 'VITE_MAILGUN_FROM_NAME':
            return 'Test App';
          default:
            return defaultValue;
        }
      });

      expect(isMailgunConfigured()).toBe(false);
    });

    test('should return false when required fields are empty strings', () => {
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        switch (key) {
          case 'VITE_MAILGUN_API_KEY':
            return '';
          case 'VITE_MAILGUN_DOMAIN':
            return 'test.domain.com';
          case 'VITE_MAILGUN_FROM_EMAIL':
            return 'noreply@test.com';
          case 'VITE_MAILGUN_BASE_URL':
            return 'https://api.mailgun.net/v3';
          case 'VITE_MAILGUN_FROM_NAME':
            return 'Test App';
          default:
            return defaultValue;
        }
      });

      expect(isMailgunConfigured()).toBe(false);
    });

    test('should return true even when optional fields are missing', () => {
      // Provide only required fields (optional ones fall back to defaults)
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        switch (key) {
          case 'VITE_MAILGUN_API_KEY':
            return 'test-api-key';
          case 'VITE_MAILGUN_DOMAIN':
            return 'test.domain.com';
          case 'VITE_MAILGUN_FROM_EMAIL':
            return 'noreply@test.com';
          // baseUrl and fromName return undefined so defaults are applied
          default:
            return defaultValue;
        }
      });

      expect(isMailgunConfigured()).toBe(true);
    });
  });

  describe('isDevelopmentMode', () => {
    test('should return true when not in production and Mailgun not configured', () => {
      mockIsProduction.mockReturnValue(false);
      mockGetEnvVar.mockReturnValue(undefined);

      expect(isDevelopmentMode()).toBe(true);
    });

    test('should return false when in production even if Mailgun not configured', () => {
      mockIsProduction.mockReturnValue(true);

      expect(isDevelopmentMode()).toBe(false);
    });

    test('should return false when Mailgun is configured regardless of environment', () => {
      mockIsProduction.mockReturnValue(false);
      mockGetEnvVar
        .mockReturnValueOnce('test-api-key')
        .mockReturnValueOnce('test.domain.com')
        .mockReturnValueOnce('https://api.mailgun.net/v3')
        .mockReturnValueOnce('Test App')
        .mockReturnValueOnce('noreply@test.com');

      expect(isDevelopmentMode()).toBe(false);
    });

    test('should return false when in production and Mailgun is configured', () => {
      mockIsProduction.mockReturnValue(true);
      mockGetEnvVar
        .mockReturnValueOnce('test-api-key')
        .mockReturnValueOnce('test.domain.com')
        .mockReturnValueOnce('https://api.mailgun.net/v3')
        .mockReturnValueOnce('Test App')
        .mockReturnValueOnce('noreply@test.com');

      expect(isDevelopmentMode()).toBe(false);
    });
  });

  describe('integration scenarios', () => {
    test('should work with complete configuration', () => {
      mockGetEnvVar.mockImplementation((key: string, defaultValue?: string) => {
        switch (key) {
          case 'VITE_MAILGUN_API_KEY':
            return 'real-api-key';
          case 'VITE_MAILGUN_DOMAIN':
            return 'mg.example.com';
          case 'VITE_MAILGUN_FROM_EMAIL':
            return 'support@example.com';
          default:
            return defaultValue;
        }
      });

      expect(isMailgunConfigured()).toBe(true);
      expect(isDevelopmentMode()).toBe(false);
    });

    test('should work in development mode', () => {
      mockGetEnvVar.mockReturnValue(undefined);
      mockIsProduction.mockReturnValue(false);

      expect(isMailgunConfigured()).toBe(false);
      expect(isDevelopmentMode()).toBe(true);
    });
  });
});