import { describe, it, expect, vi, beforeEach } from 'vitest';
import { LogoutMutation } from './LogoutMutation';
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('LogoutMutation', () => {
  let mutation: LogoutMutation;
  let mockServiceInstance: { logout: ReturnType<typeof vi.fn> };

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

  describe('execute', () => {
    describe('happy paths', () => {
      it('should successfully logout', async () => {
        // Arrange
        mockServiceInstance.logout.mockResolvedValue(Result.ok(undefined));

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

        // Assert
        expect(result.isOk()).toBe(true);
        expect(result.unwrap()).toBeUndefined();
        expect(mockServiceInstance.logout).toHaveBeenCalledTimes(1);
      });
    });

    describe('failure modes', () => {
      it('should handle service failure during logout', async () => {
        // Arrange
        const serviceError = new Error('Session expired');
        mockServiceInstance.logout.mockRejectedValue(serviceError);

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

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Session expired');
        expect(mockServiceInstance.logout).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning error result', async () => {
        // Arrange
        const domainError = { type: 'serverError', message: 'Failed to clear session' };
        mockServiceInstance.logout.mockResolvedValue(Result.err(domainError));

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

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Failed to clear session');
        expect(mockServiceInstance.logout).toHaveBeenCalledTimes(1);
      });

      it('should handle service returning unauthorized error', async () => {
        // Arrange
        const domainError = { type: 'unauthorized', message: 'Not authenticated' };
        mockServiceInstance.logout.mockResolvedValue(Result.err(domainError));

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

        // Assert
        expect(result.isErr()).toBe(true);
        expect(result.getError()).toBe('Not authenticated');
        expect(mockServiceInstance.logout).toHaveBeenCalledTimes(1);
      });
    });

    describe('error mapping', () => {
      it('should map various domain errors to mutation errors', async () => {
        // Arrange
        const testCases = [
          { domainError: { type: 'serverError', message: 'Server error' }, expectedError: 'Server error' },
          { domainError: { type: 'unauthorized', message: 'Unauthorized' }, expectedError: 'Unauthorized' },
          { domainError: { type: 'notFound', message: 'Session not found' }, expectedError: 'Session not found' },
          { domainError: { type: 'networkError', message: 'Network error' }, expectedError: 'Network error' },
        ];

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

          const result = await mutation.execute();

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

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

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

    describe('result shape', () => {
      it('should return void result on success', async () => {
        // Arrange
        mockServiceInstance.logout.mockResolvedValue(Result.ok(undefined));

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

        // Assert
        expect(result.isOk()).toBe(true);
        expect(result.unwrap()).toBeUndefined();
        expect(typeof result.unwrap()).toBe('undefined');
      });
    });
  });
});