const AuthService = require('../../src/services/AuthService');
const User = require('../../src/models/User');
const emailService = require('../../src/services/EmailService');
const jwt = require('jsonwebtoken');

// Mock dependencies
jest.mock('../../src/models/User');
jest.mock('../../src/services/EmailService');
jest.mock('jsonwebtoken');

describe('AuthService Unit Tests', () => {
    beforeEach(() => {
        jest.clearAllMocks();
    });

    describe('generateToken', () => {
        it('should generate a valid JWT token', () => {
            const mockUser = {
                id: 'user-123',
                email: 'test@example.com',
                is_verified: true
            };

            const mockToken = 'mock-jwt-token';
            jwt.sign.mockReturnValue(mockToken);

            const token = AuthService.generateToken(mockUser);

            expect(jwt.sign).toHaveBeenCalledWith(
                {
                    userId: 'user-123',
                    email: 'test@example.com',
                    isVerified: true
                },
                process.env.JWT_SECRET,
                {
                    expiresIn: process.env.JWT_EXPIRES_IN || '24h',
                    issuer: 'bookmark-manager',
                    audience: 'bookmark-manager-users'
                }
            );
            expect(token).toBe(mockToken);
        });
    });

    describe('verifyToken', () => {
        it('should verify a valid token', () => {
            const mockPayload = { userId: 'user-123', email: 'test@example.com' };
            jwt.verify.mockReturnValue(mockPayload);

            const result = AuthService.verifyToken('valid-token');

            expect(jwt.verify).toHaveBeenCalledWith(
                'valid-token',
                process.env.JWT_SECRET,
                {
                    issuer: 'bookmark-manager',
                    audience: 'bookmark-manager-users'
                }
            );
            expect(result).toEqual(mockPayload);
        });

        it('should return null for invalid token', () => {
            jwt.verify.mockImplementation(() => {
                throw new Error('Invalid token');
            });

            const result = AuthService.verifyToken('invalid-token');

            expect(result).toBeNull();
        });
    });

    describe('register', () => {
        it('should successfully register a new user', async () => {
            const mockUser = {
                id: 'user-123',
                email: 'test@example.com',
                toSafeObject: () => ({ id: 'user-123', email: 'test@example.com' })
            };

            User.create.mockResolvedValue(mockUser);
            emailService.sendVerificationEmail.mockResolvedValue({ message: 'Email sent' });

            const result = await AuthService.register('test@example.com', 'password123');

            expect(User.create).toHaveBeenCalledWith({
                email: 'test@example.com',
                password: 'password123'
            });
            expect(emailService.sendVerificationEmail).toHaveBeenCalled();
            expect(result.success).toBe(true);
            expect(result.message).toBe('User registered successfully. Please check your email for verification.');
        });

        it('should handle registration failure', async () => {
            User.create.mockRejectedValue(new Error('Email already exists'));

            const result = await AuthService.register('test@example.com', 'password123');

            expect(result.success).toBe(false);
            expect(result.message).toBe('Email already exists');
        });
    });

    describe('login', () => {
        it('should successfully login a verified user', async () => {
            const mockUser = {
                id: 'user-123',
                email: 'test@example.com',
                is_verified: true,
                toSafeObject: () => ({ id: 'user-123', email: 'test@example.com' })
            };

            User.authenticate.mockResolvedValue(mockUser);
            jwt.sign.mockReturnValue('mock-token');

            const result = await AuthService.login('test@example.com', 'password123');

            expect(User.authenticate).toHaveBeenCalledWith('test@example.com', 'password123');
            expect(result.success).toBe(true);
            expect(result.token).toBe('mock-token');
            expect(result.user).toEqual({ id: 'user-123', email: 'test@example.com' });
        });

        it('should fail login for invalid credentials', async () => {
            User.authenticate.mockResolvedValue(null);

            const result = await AuthService.login('test@example.com', 'wrongpassword');

            expect(result.success).toBe(false);
            expect(result.message).toBe('Invalid email or password');
        });

        it('should fail login for unverified user', async () => {
            const mockUser = {
                id: 'user-123',
                email: 'test@example.com',
                is_verified: false
            };

            User.authenticate.mockResolvedValue(mockUser);

            const result = await AuthService.login('test@example.com', 'password123');

            expect(result.success).toBe(false);
            expect(result.message).toBe('Please verify your email before logging in');
            expect(result.requiresVerification).toBe(true);
        });
    });

    describe('verifyEmail', () => {
        it('should successfully verify email', async () => {
            const mockUser = {
                id: 'user-123',
                is_verified: false,
                verifyEmail: jest.fn().mockResolvedValue(true)
            };

            User.findByVerificationToken.mockResolvedValue(mockUser);

            const result = await AuthService.verifyEmail('valid-token');

            expect(User.findByVerificationToken).toHaveBeenCalledWith('valid-token');
            expect(mockUser.verifyEmail).toHaveBeenCalled();
            expect(result.success).toBe(true);
            expect(result.message).toBe('Email verified successfully');
        });

        it('should handle invalid verification token', async () => {
            User.findByVerificationToken.mockResolvedValue(null);

            const result = await AuthService.verifyEmail('invalid-token');

            expect(result.success).toBe(false);
            expect(result.message).toBe('Invalid or expired verification token');
        });

        it('should handle already verified email', async () => {
            const mockUser = {
                id: 'user-123',
                is_verified: true
            };

            User.findByVerificationToken.mockResolvedValue(mockUser);

            const result = await AuthService.verifyEmail('valid-token');

            expect(result.success).toBe(true);
            expect(result.message).toBe('Email already verified');
        });
    });

    describe('requestPasswordReset', () => {
        it('should send reset email for existing user', async () => {
            const mockUser = {
                id: 'user-123',
                email: 'test@example.com',
                setResetToken: jest.fn().mockResolvedValue('reset-token')
            };

            User.findByEmail.mockResolvedValue(mockUser);
            emailService.sendPasswordResetEmail.mockResolvedValue({ message: 'Email sent' });

            const result = await AuthService.requestPasswordReset('test@example.com');

            expect(User.findByEmail).toHaveBeenCalledWith('test@example.com');
            expect(mockUser.setResetToken).toHaveBeenCalled();
            expect(emailService.sendPasswordResetEmail).toHaveBeenCalledWith(mockUser, 'reset-token');
            expect(result.success).toBe(true);
        });

        it('should not reveal if email does not exist', async () => {
            User.findByEmail.mockResolvedValue(null);

            const result = await AuthService.requestPasswordReset('nonexistent@example.com');

            expect(result.success).toBe(true);
            expect(result.message).toBe('If an account with that email exists, a password reset link has been sent.');
        });
    });

    describe('resetPassword', () => {
        it('should successfully reset password', async () => {
            const mockUser = {
                id: 'user-123',
                updatePassword: jest.fn().mockResolvedValue(true)
            };

            User.findByResetToken.mockResolvedValue(mockUser);

            const result = await AuthService.resetPassword('valid-token', 'newPassword123');

            expect(User.findByResetToken).toHaveBeenCalledWith('valid-token');
            expect(mockUser.updatePassword).toHaveBeenCalledWith('newPassword123');
            expect(result.success).toBe(true);
            expect(result.message).toBe('Password reset successfully');
        });

        it('should handle invalid reset token', async () => {
            User.findByResetToken.mockResolvedValue(null);

            const result = await AuthService.resetPassword('invalid-token', 'newPassword123');

            expect(result.success).toBe(false);
            expect(result.message).toBe('Invalid or expired reset token');
        });
    });

    describe('changePassword', () => {
        it('should successfully change password', async () => {
            const mockUser = {
                id: 'user-123',
                password_hash: 'hashed-password',
                updatePassword: jest.fn().mockResolvedValue(true)
            };

            User.findById.mockResolvedValue(mockUser);
            User.verifyPassword.mockResolvedValue(true);

            const result = await AuthService.changePassword('user-123', 'currentPassword', 'newPassword123');

            expect(User.findById).toHaveBeenCalledWith('user-123');
            expect(User.verifyPassword).toHaveBeenCalledWith('currentPassword', 'hashed-password');
            expect(mockUser.updatePassword).toHaveBeenCalledWith('newPassword123');
            expect(result.success).toBe(true);
        });

        it('should fail with incorrect current password', async () => {
            const mockUser = {
                id: 'user-123',
                password_hash: 'hashed-password'
            };

            User.findById.mockResolvedValue(mockUser);
            User.verifyPassword.mockResolvedValue(false);

            const result = await AuthService.changePassword('user-123', 'wrongPassword', 'newPassword123');

            expect(result.success).toBe(false);
            expect(result.message).toBe('Current password is incorrect');
        });
    });

    describe('refreshToken', () => {
        it('should successfully refresh token', async () => {
            const mockPayload = { userId: 'user-123' };
            const mockUser = {
                id: 'user-123',
                toSafeObject: () => ({ id: 'user-123', email: 'test@example.com' })
            };

            jwt.verify.mockReturnValue(mockPayload);
            User.findById.mockResolvedValue(mockUser);
            jwt.sign.mockReturnValue('new-token');

            const result = await AuthService.refreshToken('old-token');

            expect(jwt.verify).toHaveBeenCalledWith('old-token', process.env.JWT_SECRET, {
                issuer: 'bookmark-manager',
                audience: 'bookmark-manager-users'
            });
            expect(User.findById).toHaveBeenCalledWith('user-123');
            expect(result.success).toBe(true);
            expect(result.token).toBe('new-token');
        });

        it('should fail with invalid token', async () => {
            jwt.verify.mockImplementation(() => {
                throw new Error('Invalid token');
            });

            const result = await AuthService.refreshToken('invalid-token');

            expect(result.success).toBe(false);
            expect(result.message).toBe('Invalid token');
        });
    });

    describe('validateAuthToken', () => {
        it('should validate token and return user', async () => {
            const mockPayload = { userId: 'user-123' };
            const mockUser = {
                id: 'user-123',
                is_verified: true
            };

            jwt.verify.mockReturnValue(mockPayload);
            User.findById.mockResolvedValue(mockUser);

            const result = await AuthService.validateAuthToken('valid-token');

            expect(result).toEqual(mockUser);
        });

        it('should return null for invalid token', async () => {
            jwt.verify.mockImplementation(() => {
                throw new Error('Invalid token');
            });

            const result = await AuthService.validateAuthToken('invalid-token');

            expect(result).toBeNull();
        });

        it('should return null for unverified user', async () => {
            const mockPayload = { userId: 'user-123' };
            const mockUser = {
                id: 'user-123',
                is_verified: false
            };

            jwt.verify.mockReturnValue(mockPayload);
            User.findById.mockResolvedValue(mockUser);

            const result = await AuthService.validateAuthToken('valid-token');

            expect(result).toBeNull();
        });
    });
});