import { describe, it, expect, vi, beforeEach } from 'vitest';
import { LoginMutation } from './LoginMutation';
import { AuthService } from '@/lib/services/auth/AuthService';
import { Result } from '@/lib/contracts/Result';
import { SessionViewModel } from '@/lib/view-models/SessionViewModel';

// Mock dependencies
vi.mock('@/lib/services/auth/AuthService', () => {
  return {
    AuthService: vi.fn(),
  };
});

describe('LoginMutation', () => {
  let mutation: LoginMutation;
  let mockServiceInstance: { login: ReturnType<typeof vi.fn> };

  beforeEach(() => {
    vi.clearAllMocks();
    mutation = new LoginMutation();
    mockServiceInstance = {
      login: vi.fn(),
    };
    // Use mockImplementation to return the instance
    (AuthService as any).mockImplementation(function() {
      return mockServiceInstance;
    });
  });

  describe('execute', () => {
    describe('happy paths', () => {
      it('should successfully login with valid credentials', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'password123' };
        const mockUser = {
          userId: 'user-123',
          email: 'test@example.com',
          displayName: 'Test User',
          role: 'user',
        };
        const sessionViewModel = new SessionViewModel(mockUser);
        mockServiceInstance.login.mockResolvedValue(Result.ok(sessionViewModel));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isOk()).toBe(true);
        expect(result.unwrap()).toBeInstanceOf(SessionViewModel);
        expect(result.unwrap().userId).toBe('user-123');
        expect(result.unwrap().email).toBe('test@example.com');
        expect(mockServiceInstance.login).toHaveBeenCalledWith(input);
        expect(mockServiceInstance.login).toHaveBeenCalledTimes(1);
      });

      it('should handle login with rememberMe option', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'password123', rememberMe: true };
        const mockUser = {
          userId: 'user-123',
          email: 'test@example.com',
          displayName: 'Test User',
          role: 'user',
        };
        const sessionViewModel = new SessionViewModel(mockUser);
        mockServiceInstance.login.mockResolvedValue(Result.ok(sessionViewModel));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isOk()).toBe(true);
        expect(result.unwrap()).toBeInstanceOf(SessionViewModel);
        expect(mockServiceInstance.login).toHaveBeenCalledWith(input);
      });

      it('should handle login with optional fields', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'password123' };
        const mockUser = {
          userId: 'user-123',
          email: 'test@example.com',
          displayName: 'Test User',
          role: 'user',
          primaryDriverId: 'driver-456',
          avatarUrl: 'https://example.com/avatar.jpg',
        };
        const sessionViewModel = new SessionViewModel(mockUser);
        mockServiceInstance.login.mockResolvedValue(Result.ok(sessionViewModel));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isOk()).toBe(true);
        const session = result.unwrap();
        expect(session.userId).toBe('user-123');
        expect(session.driverId).toBe('driver-456');
        expect(session.avatarUrl).toBe('https://example.com/avatar.jpg');
      });
    });

    describe('failure modes', () => {
      it('should handle service failure during login', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'wrongpassword' };
        const serviceError = new Error('Invalid credentials');
        mockServiceInstance.login.mockRejectedValue(serviceError);

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Invalid credentials');
        expect(mockServiceInstance.login).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning unauthorized error', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'wrongpassword' };
        const domainError = { type: 'unauthorized', message: 'Invalid email or password' };
        mockServiceInstance.login.mockResolvedValue(Result.err(domainError));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Invalid email or password');
        expect(mockServiceInstance.login).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning validation error', async () => {
        // Arrange
        const input = { email: 'invalid-email', password: 'password123' };
        const domainError = { type: 'validationError', message: 'Invalid email format' };
        mockServiceInstance.login.mockResolvedValue(Result.err(domainError));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Invalid email format');
        expect(mockServiceInstance.login).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning accountLocked error', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'password123' };
        const domainError = { type: 'unauthorized', message: 'Account locked due to too many failed attempts' };
        mockServiceInstance.login.mockResolvedValue(Result.err(domainError));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Account locked due to too many failed attempts');
        expect(mockServiceInstance.login).toHaveBeenCalledTimes(1);
      });
    });

    describe('error mapping', () => {
      it('should map various domain errors to mutation errors', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'password123' };
        const testCases = [
          { domainError: { type: 'unauthorized', message: 'Invalid credentials' }, expectedError: 'Invalid credentials' },
          { domainError: { type: 'validationError', message: 'Validation failed' }, expectedError: 'Validation failed' },
          { domainError: { type: 'serverError', message: 'Server error' }, expectedError: 'Server error' },
          { domainError: { type: 'notFound', message: 'User not found' }, expectedError: 'User not found' },
        ];

        for (const testCase of testCases) {
          mockServiceInstance.login.mockResolvedValue(Result.err(testCase.domainError));

          const result = await mutation.execute(input);

          expect(result.isErr()).toBe(true);
          expect(result.getError()).toBe(testCase.expectedError);
        }
      });
    });

    describe('input validation', () => {
      it('should accept valid email and password input', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'password123' };
        const mockUser = {
          userId: 'user-123',
          email: 'test@example.com',
          displayName: 'Test User',
          role: 'user',
        };
        const sessionViewModel = new SessionViewModel(mockUser);
        mockServiceInstance.login.mockResolvedValue(Result.ok(sessionViewModel));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isOk()).toBe(true);
        expect(mockServiceInstance.login).toHaveBeenCalledTimes(1);
      });

      it('should handle empty email gracefully', async () => {
        // Arrange
        const input = { email: '', password: 'password123' };
        const mockUser = {
          userId: 'user-123',
          email: '',
          displayName: 'Test User',
          role: 'user',
        };
        const sessionViewModel = new SessionViewModel(mockUser);
        mockServiceInstance.login.mockResolvedValue(Result.ok(sessionViewModel));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isOk()).toBe(true);
        expect(mockServiceInstance.login).toHaveBeenCalledWith(input);
      });

      it('should handle empty password gracefully', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: '' };
        const mockUser = {
          userId: 'user-123',
          email: 'test@example.com',
          displayName: 'Test User',
          role: 'user',
        };
        const sessionViewModel = new SessionViewModel(mockUser);
        mockServiceInstance.login.mockResolvedValue(Result.ok(sessionViewModel));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isOk()).toBe(true);
        expect(mockServiceInstance.login).toHaveBeenCalledWith(input);
      });
    });

    describe('service instantiation', () => {
      it('should create AuthService instance', () => {
        // Arrange & Act
        const mutation = new LoginMutation();

        // Assert
        expect(mutation).toBeInstanceOf(LoginMutation);
      });
    });

    describe('result shape', () => {
      it('should return SessionViewModel with correct properties', async () => {
        // Arrange
        const input = { email: 'test@example.com', password: 'password123' };
        const mockUser = {
          userId: 'user-123',
          email: 'test@example.com',
          displayName: 'Test User',
          role: 'admin',
          primaryDriverId: 'driver-456',
          avatarUrl: 'https://example.com/avatar.jpg',
        };
        const sessionViewModel = new SessionViewModel(mockUser);
        mockServiceInstance.login.mockResolvedValue(Result.ok(sessionViewModel));

        // Act
        const result = await mutation.execute(input);

        // Assert
        expect(result.isOk()).toBe(true);
        const session = result.unwrap();
        expect(session).toBeInstanceOf(SessionViewModel);
        expect(session.userId).toBe('user-123');
        expect(session.email).toBe('test@example.com');
        expect(session.displayName).toBe('Test User');
        expect(session.role).toBe('admin');
        expect(session.driverId).toBe('driver-456');
        expect(session.avatarUrl).toBe('https://example.com/avatar.jpg');
        expect(session.isAuthenticated).toBe(true);
      });
    });
  });
});