fix: Code for category

internal/service/category.go

@@ -25,6 +25,7 @@ type CategoryRepository interface {
 // CategoryInput carries the mutable fields of a category.
 type CategoryInput struct {
 	ParentID    *uuid.UUID
+	Code        string
 	Name        string
 	Description string
 }
@@ -39,13 +40,17 @@ func NewCategoryService(repo CategoryRepository) *CategoryService {
 	return &CategoryService{repo: repo}
 }
 
-// Create validates the parent (if any) and stores a new category.
+// Create validates the code and parent (if any) and stores a new category.
 func (s *CategoryService) Create(ctx context.Context, in CategoryInput) (domain.Category, error) {
+	if !domain.ValidSlug(in.Code) {
+		return domain.Category{}, fmt.Errorf("%w: code must be a slug (lowercase latin letters, digits, and dashes)", domain.ErrValidation)
+	}
 	if err := s.ensureParentExists(ctx, in.ParentID); err != nil {
 		return domain.Category{}, err
 	}
 	return s.repo.Create(ctx, domain.Category{
 		ParentID:    in.ParentID,
+		Code:        in.Code,
 		Name:        in.Name,
 		Description: in.Description,
 	})
@@ -61,8 +66,11 @@ func (s *CategoryService) List(ctx context.Context, parentID *uuid.UUID) ([]doma
 	return s.repo.List(ctx, parentID)
 }
 
-// Update validates the parent change (existence + no cycles) and stores it.
+// Update validates the code and parent change (existence + no cycles) and stores it.
 func (s *CategoryService) Update(ctx context.Context, id uuid.UUID, in CategoryInput) (domain.Category, error) {
+	if !domain.ValidSlug(in.Code) {
+		return domain.Category{}, fmt.Errorf("%w: code must be a slug (lowercase latin letters, digits, and dashes)", domain.ErrValidation)
+	}
 	if _, err := s.repo.GetByID(ctx, id); err != nil {
 		return domain.Category{}, err
 	}
@@ -75,6 +83,7 @@ func (s *CategoryService) Update(ctx context.Context, id uuid.UUID, in CategoryI
 	return s.repo.Update(ctx, domain.Category{
 		ID:          id,
 		ParentID:    in.ParentID,
+		Code:        in.Code,
 		Name:        in.Name,
 		Description: in.Description,
 	})