import { EmailVerificationService } from '../emailVerification.service';
import { AuthenticatedUser } from '../auth.types';
import { AccountStatus } from '../auth.constants';

// Mock the mailgun service
jest.mock('../../mailgun.service', () => ({
  mailgunService: {
    sendVerificationEmail: jest.fn().mockResolvedValue(true),
    sendPasswordResetEmail: jest.fn().mockResolvedValue(true),
  },
}));

// Mock the couchdb.factory service
jest.mock('../../couchdb.factory', () => ({
  dbService: {
    findUserByEmail: jest.fn(),
    updateUser: jest.fn(),
  },
}));

describe('EmailVerificationService', () => {
  let emailVerificationService: EmailVerificationService;
  let mockMailgunService: any;
  let mockDbService: any;

  const createMockUser = (
    overrides: Partial<AuthenticatedUser> = {}
  ): AuthenticatedUser => ({
    _id: 'user1',
    _rev: 'mock-rev-1',
    email: 'test@example.com',
    username: 'testuser',
    password: 'password',
    emailVerified: false,
    status: AccountStatus.PENDING,
    ...overrides,
  });

  beforeEach(async () => {
    emailVerificationService = new EmailVerificationService();
    // Clear localStorage before each test
    localStorage.clear();
    // Reset all mocks
    jest.clearAllMocks();

    // Get mocked services
    const mailgunModule = await import('../../mailgun.service');
    const dbModule = await import('../../couchdb.factory');
    mockMailgunService = mailgunModule.mailgunService;
    mockDbService = dbModule.dbService;
  });

  describe('generateVerificationToken', () => {
    test('should generate a valid verification token', async () => {
      // Arrange
      const user = createMockUser();
      mockMailgunService.sendVerificationEmail.mockResolvedValue(true);

      // Act
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Assert
      expect(verificationToken).toBeDefined();
      expect(verificationToken.token).toBeDefined();
      expect(verificationToken.token).toHaveLength(32); // UUID without hyphens
      expect(verificationToken.expiresAt).toBeDefined();
      expect(verificationToken.userId).toBe(user._id);
      expect(verificationToken.email).toBe(user.email);
      expect(verificationToken.expiresAt.getTime()).toBeGreaterThan(Date.now());

      // Verify token is stored in localStorage
      const storedTokens = JSON.parse(
        localStorage.getItem('verification_tokens') || '[]'
      );
      expect(storedTokens).toHaveLength(1);
      expect(storedTokens[0].token).toBe(verificationToken.token);
      expect(storedTokens[0].userId).toBe(user._id);
      expect(storedTokens[0].email).toBe(user.email);
    });

    test('should send verification email when user has email', async () => {
      // Arrange
      const user = createMockUser({ email: 'user@example.com' });
      mockMailgunService.sendVerificationEmail.mockResolvedValue(true);

      // Act
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Assert
      expect(mockMailgunService.sendVerificationEmail).toHaveBeenCalledWith(
        user.email,
        verificationToken.token
      );
    });

    test('should handle email sending failure gracefully', async () => {
      // Arrange
      const user = createMockUser({ email: 'user@example.com' });
      mockMailgunService.sendVerificationEmail.mockResolvedValue(false);

      // Act
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Assert
      expect(verificationToken).toBeDefined();
      expect(verificationToken.token).toBeDefined();
      expect(mockMailgunService.sendVerificationEmail).toHaveBeenCalledWith(
        user.email,
        verificationToken.token
      );
    });

    test('should not send email when user has no email', async () => {
      // Arrange
      const user = createMockUser({ email: '' });

      // Act
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Assert
      expect(verificationToken).toBeDefined();
      expect(mockMailgunService.sendVerificationEmail).not.toHaveBeenCalled();
    });

    test('should generate unique tokens for multiple calls', async () => {
      // Arrange
      const user1 = createMockUser({
        _id: 'user1',
        email: 'user1@example.com',
      });
      const user2 = createMockUser({
        _id: 'user2',
        email: 'user2@example.com',
      });

      // Act
      const token1 =
        await emailVerificationService.generateVerificationToken(user1);
      const token2 =
        await emailVerificationService.generateVerificationToken(user2);

      // Assert
      expect(token1.token).not.toBe(token2.token);
      expect(token1.userId).toBe('user1');
      expect(token2.userId).toBe('user2');

      // Verify both tokens are stored
      const storedTokens = JSON.parse(
        localStorage.getItem('verification_tokens') || '[]'
      );
      expect(storedTokens).toHaveLength(2);
    });
  });

  describe('validateVerificationToken', () => {
    test('should validate a valid token and return user', async () => {
      // Arrange
      const user = createMockUser();
      mockDbService.findUserByEmail.mockResolvedValue(user);

      // Generate and store a token first
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Act
      const validatedUser =
        await emailVerificationService.validateVerificationToken(
          verificationToken.token
        );

      // Assert
      expect(validatedUser).toBeDefined();
      expect(validatedUser!._id).toBe(user._id);
      expect(validatedUser!.email).toBe(user.email);
      expect(mockDbService.findUserByEmail).toHaveBeenCalledWith(user.email);
    });

    test('should return null for non-existent token', async () => {
      // Act
      const validatedUser =
        await emailVerificationService.validateVerificationToken(
          'invalid-token'
        );

      // Assert
      expect(validatedUser).toBeNull();
      expect(mockDbService.findUserByEmail).not.toHaveBeenCalled();
    });

    test('should return null for expired token', async () => {
      // Arrange
      const user = createMockUser();
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Manually expire the token in localStorage
      const tokens = JSON.parse(
        localStorage.getItem('verification_tokens') || '[]'
      );
      tokens[0].expiresAt = new Date(
        Date.now() - 1000 * 60 * 60 * 24
      ).toISOString(); // 24 hours ago
      localStorage.setItem('verification_tokens', JSON.stringify(tokens));

      // Act
      const validatedUser =
        await emailVerificationService.validateVerificationToken(
          verificationToken.token
        );

      // Assert
      expect(validatedUser).toBeNull();
      expect(mockDbService.findUserByEmail).not.toHaveBeenCalled();
    });

    test('should return null when user not found in database', async () => {
      // Arrange
      const user = createMockUser();
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);
      mockDbService.findUserByEmail.mockResolvedValue(null);

      // Act
      const validatedUser =
        await emailVerificationService.validateVerificationToken(
          verificationToken.token
        );

      // Assert
      expect(validatedUser).toBeNull();
      expect(mockDbService.findUserByEmail).toHaveBeenCalledWith(user.email);
    });

    test('should handle database errors gracefully', async () => {
      // Arrange
      const user = createMockUser();
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);
      mockDbService.findUserByEmail.mockRejectedValue(
        new Error('Database error')
      );

      // Act & Assert
      await expect(
        emailVerificationService.validateVerificationToken(
          verificationToken.token
        )
      ).rejects.toThrow('Database error');
    });
  });

  describe('markEmailVerified', () => {
    test('should update user status to active and mark email verified', async () => {
      // Arrange
      const user = createMockUser();
      const expectedUpdatedUser = {
        ...user,
        emailVerified: true,
        status: AccountStatus.ACTIVE,
      };

      // Store a verification token first
      await emailVerificationService.generateVerificationToken(user);
      mockDbService.updateUser.mockResolvedValue(expectedUpdatedUser);

      // Act
      await emailVerificationService.markEmailVerified(user);

      // Assert
      expect(mockDbService.updateUser).toHaveBeenCalledWith(
        expectedUpdatedUser
      );
    });

    test('should remove verification token after marking verified', async () => {
      // Arrange
      const user = createMockUser();
      await emailVerificationService.generateVerificationToken(user);
      mockDbService.updateUser.mockResolvedValue(user);

      // Verify token exists before
      let tokens = JSON.parse(
        localStorage.getItem('verification_tokens') || '[]'
      );
      expect(tokens).toHaveLength(1);

      // Act
      await emailVerificationService.markEmailVerified(user);

      // Assert - token should be removed
      tokens = JSON.parse(localStorage.getItem('verification_tokens') || '[]');
      expect(tokens).toHaveLength(0);
    });

    test('should only remove tokens for the specific user', async () => {
      // Arrange
      const user1 = createMockUser({
        _id: 'user1',
        email: 'user1@example.com',
      });
      const user2 = createMockUser({
        _id: 'user2',
        email: 'user2@example.com',
      });

      await emailVerificationService.generateVerificationToken(user1);
      await emailVerificationService.generateVerificationToken(user2);
      mockDbService.updateUser.mockResolvedValue(user1);

      // Verify both tokens exist
      let tokens = JSON.parse(
        localStorage.getItem('verification_tokens') || '[]'
      );
      expect(tokens).toHaveLength(2);

      // Act - verify only user1
      await emailVerificationService.markEmailVerified(user1);

      // Assert - only user1's token should be removed
      tokens = JSON.parse(localStorage.getItem('verification_tokens') || '[]');
      expect(tokens).toHaveLength(1);
      expect(tokens[0].userId).toBe('user2');
    });

    test('should handle database update errors', async () => {
      // Arrange
      const user = createMockUser();
      mockDbService.updateUser.mockRejectedValue(new Error('Update failed'));

      // Act & Assert
      await expect(
        emailVerificationService.markEmailVerified(user)
      ).rejects.toThrow('Update failed');
    });
  });

  describe('sendPasswordResetEmail', () => {
    test('should delegate to mailgun service', async () => {
      // Arrange
      const email = 'user@example.com';
      const token = 'reset-token';
      mockMailgunService.sendPasswordResetEmail.mockResolvedValue(true);

      // Act
      const result = await emailVerificationService.sendPasswordResetEmail(
        email,
        token
      );

      // Assert
      expect(result).toBe(true);
      expect(mockMailgunService.sendPasswordResetEmail).toHaveBeenCalledWith(
        email,
        token
      );
    });

    test('should return false when email sending fails', async () => {
      // Arrange
      const email = 'user@example.com';
      const token = 'reset-token';
      mockMailgunService.sendPasswordResetEmail.mockResolvedValue(false);

      // Act
      const result = await emailVerificationService.sendPasswordResetEmail(
        email,
        token
      );

      // Assert
      expect(result).toBe(false);
      expect(mockMailgunService.sendPasswordResetEmail).toHaveBeenCalledWith(
        email,
        token
      );
    });
  });

  describe('integration scenarios', () => {
    test('should complete full verification flow', async () => {
      // Arrange
      const user = createMockUser();
      mockDbService.findUserByEmail.mockResolvedValue(user);
      mockDbService.updateUser.mockResolvedValue({
        ...user,
        emailVerified: true,
        status: AccountStatus.ACTIVE,
      });

      // Act - Generate token
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Act - Validate token
      const validatedUser =
        await emailVerificationService.validateVerificationToken(
          verificationToken.token
        );

      // Act - Mark as verified
      await emailVerificationService.markEmailVerified(validatedUser!);

      // Assert
      expect(validatedUser).toBeDefined();
      expect(mockDbService.updateUser).toHaveBeenCalledWith({
        ...user,
        emailVerified: true,
        status: AccountStatus.ACTIVE,
      });

      // Verify token is cleaned up
      const tokens = JSON.parse(
        localStorage.getItem('verification_tokens') || '[]'
      );
      expect(tokens).toHaveLength(0);
    });

    test('should handle token expiration during flow', async () => {
      // Arrange
      const user = createMockUser();
      const verificationToken =
        await emailVerificationService.generateVerificationToken(user);

      // Simulate time passing - expire the token
      const tokens = JSON.parse(
        localStorage.getItem('verification_tokens') || '[]'
      );
      tokens[0].expiresAt = new Date(Date.now() - 1000).toISOString(); // 1 second ago
      localStorage.setItem('verification_tokens', JSON.stringify(tokens));

      // Act
      const validatedUser =
        await emailVerificationService.validateVerificationToken(
          verificationToken.token
        );

      // Assert
      expect(validatedUser).toBeNull();
    });
  });
});