first commit

internal/service/auth_service.go

@@ -0,0 +1,106 @@
+package service
+
+import (
+	"errors"
+
+	"homework-manager/internal/models"
+	"homework-manager/internal/repository"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+var (
+	ErrUserNotFound       = errors.New("user not found")
+	ErrEmailAlreadyExists = errors.New("email already exists")
+	ErrInvalidCredentials = errors.New("invalid credentials")
+)
+
+type AuthService struct {
+	userRepo *repository.UserRepository
+}
+
+func NewAuthService() *AuthService {
+	return &AuthService{
+		userRepo: repository.NewUserRepository(),
+	}
+}
+
+func (s *AuthService) Register(email, password, name string) (*models.User, error) {
+	// Check if email already exists
+	_, err := s.userRepo.FindByEmail(email)
+	if err == nil {
+		return nil, ErrEmailAlreadyExists
+	}
+
+	// Hash password
+	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return nil, err
+	}
+
+	// Determine role (first user is admin)
+	role := "user"
+	count, _ := s.userRepo.Count()
+	if count == 0 {
+		role = "admin"
+	}
+
+	user := &models.User{
+		Email:        email,
+		PasswordHash: string(hashedPassword),
+		Name:         name,
+		Role:         role,
+	}
+
+	if err := s.userRepo.Create(user); err != nil {
+		return nil, err
+	}
+
+	return user, nil
+}
+
+func (s *AuthService) Login(email, password string) (*models.User, error) {
+	user, err := s.userRepo.FindByEmail(email)
+	if err != nil {
+		return nil, ErrInvalidCredentials
+	}
+
+	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(password)); err != nil {
+		return nil, ErrInvalidCredentials
+	}
+
+	return user, nil
+}
+
+func (s *AuthService) GetUserByID(id uint) (*models.User, error) {
+	return s.userRepo.FindByID(id)
+}
+
+func (s *AuthService) ChangePassword(userID uint, oldPassword, newPassword string) error {
+	user, err := s.userRepo.FindByID(userID)
+	if err != nil {
+		return ErrUserNotFound
+	}
+
+	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(oldPassword)); err != nil {
+		return ErrInvalidCredentials
+	}
+
+	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(newPassword), bcrypt.DefaultCost)
+	if err != nil {
+		return err
+	}
+
+	user.PasswordHash = string(hashedPassword)
+	return s.userRepo.Update(user)
+}
+
+func (s *AuthService) UpdateProfile(userID uint, name string) error {
+	user, err := s.userRepo.FindByID(userID)
+	if err != nil {
+		return ErrUserNotFound
+	}
+
+	user.Name = name
+	return s.userRepo.Update(user)
+}