import { describe, it, expect, vi, beforeEach } from 'vitest';
import { ForgotPasswordMutation } from './ForgotPasswordMutation';
import { AuthService } from '@/lib/services/auth/AuthService';
import { Result } from '@/lib/contracts/Result';

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

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

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

  describe('execute', () => {
    describe('happy paths', () => {
      it('should successfully send forgot password request', async () => {
        // Arrange
        const input = { email: 'test@example.com' };
        const serviceOutput = { message: 'Reset link sent', magicLink: 'https://example.com/reset' };
        mockServiceInstance.forgotPassword.mockResolvedValue(Result.ok(serviceOutput));

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

        // Assert
        expect(result.isOk()).toBe(true);
        expect(result.unwrap()).toEqual(serviceOutput);
        expect(mockServiceInstance.forgotPassword).toHaveBeenCalledWith(input);
        expect(mockServiceInstance.forgotPassword).toHaveBeenCalledTimes(1);
      });

      it('should handle forgot password request without magicLink', async () => {
        // Arrange
        const input = { email: 'test@example.com' };
        const serviceOutput = { message: 'Reset link sent' };
        mockServiceInstance.forgotPassword.mockResolvedValue(Result.ok(serviceOutput));

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

        // Assert
        expect(result.isOk()).toBe(true);
        expect(result.unwrap()).toEqual(serviceOutput);
        expect(mockServiceInstance.forgotPassword).toHaveBeenCalledWith(input);
      });
    });

    describe('failure modes', () => {
      it('should handle service failure during forgot password request', async () => {
        // Arrange
        const input = { email: 'test@example.com' };
        const serviceError = new Error('Service error');
        mockServiceInstance.forgotPassword.mockRejectedValue(serviceError);

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

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Service error');
        expect(mockServiceInstance.forgotPassword).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning error result', async () => {
        // Arrange
        const input = { email: 'test@example.com' };
        const domainError = { type: 'serverError', message: 'Email not found' };
        mockServiceInstance.forgotPassword.mockResolvedValue(Result.err(domainError));

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

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Email not found');
        expect(mockServiceInstance.forgotPassword).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning validation error', async () => {
        // Arrange
        const input = { email: 'invalid-email' };
        const domainError = { type: 'validationError', message: 'Invalid email format' };
        mockServiceInstance.forgotPassword.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.forgotPassword).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning rate limit error', async () => {
        // Arrange
        const input = { email: 'test@example.com' };
        const domainError = { type: 'rateLimit', message: 'Too many requests' };
        mockServiceInstance.forgotPassword.mockResolvedValue(Result.err(domainError));

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

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Too many requests');
        expect(mockServiceInstance.forgotPassword).toHaveBeenCalledTimes(1);
      });
    });

    describe('error mapping', () => {
      it('should map various domain errors to mutation errors', async () => {
        // Arrange
        const input = { email: 'test@example.com' };
        const testCases = [
          { domainError: { type: 'serverError', message: 'Server error' }, expectedError: 'Server error' },
          { domainError: { type: 'validationError', message: 'Validation error' }, expectedError: 'Validation error' },
          { domainError: { type: 'notFound', message: 'Not found' }, expectedError: 'Not found' },
          { domainError: { type: 'rateLimit', message: 'Rate limit exceeded' }, expectedError: 'Rate limit exceeded' },
        ];

        for (const testCase of testCases) {
          mockServiceInstance.forgotPassword.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 input', async () => {
        // Arrange
        const input = { email: 'test@example.com' };
        mockServiceInstance.forgotPassword.mockResolvedValue(
          Result.ok({ message: 'Reset link sent' })
        );

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

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

      it('should handle empty email gracefully', async () => {
        // Arrange
        const input = { email: '' };
        mockServiceInstance.forgotPassword.mockResolvedValue(
          Result.ok({ message: 'Reset link sent' })
        );

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

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

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

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