fix(validation): scoped duplicate checks for Category and Food

[iRahmanG]

Summary

This PR introduces corrected duplicate validation logic to ensure data integrity:

• Category: Added per‑menu duplicate name validation using existsByNameIgnoreCaseAndMenu_MenuId.
• Food: Added per‑category duplicate name validation using existsByNameIgnoreCaseAndCategory_CategoryId.

Why

The earlier PR (#160) attempted similar changes but contained bugs. This new PR provides a clean, corrected implementation with proper repository methods and service logic.

Notes

• Other modules (Menu, Order, Restaurant, User) already had scoped validation checks in place.
• This PR focuses only on the missing pieces (Category and Food).
• If additional validation is expected, please highlight it so I can address it in a follow‑up.

Close Issue: #156

[Copilot]

Pull request overview

This PR adds per-scope duplicate name validation for Category (per menu) and Food (per category), replacing the previous global existsByNameIgnoreCase checks. It addresses issue #156 by introducing repository methods that include the parent scope, and adds a required menuId field on CategoryRequestDTO so the category create flow can be scoped.

Changes:

• Adds existsByNameIgnoreCaseAndMenu_MenuId on CategoryRepository and uses it in CategoryServiceImpl.createCategory; adds required menuId to CategoryRequestDTO.
• Adds existsByNameIgnoreCaseAndCategory_CategoryId on FoodRepository and uses it in both createFood and updateFood, replacing the global duplicate-name check.
• Adds debug/warn logging around the new duplicate detection paths.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
RestroHub/src/main/java/com/restroly/qrmenu/category/dto/CategoryRequestDTO.java	Adds @NotNull Long menuId so create requests carry the menu scope for duplicate validation.
RestroHub/src/main/java/com/restroly/qrmenu/category/repository/CategoryRepository.java	New derived query existsByNameIgnoreCaseAndMenu_MenuId for per-menu duplicate detection.
RestroHub/src/main/java/com/restroly/qrmenu/category/service/CategoryServiceImpl.java	Adds per-menu duplicate check in createCategory, throwing DuplicateResourceException.
RestroHub/src/main/java/com/restroly/qrmenu/food/repository/FoodRepository.java	New derived query existsByNameIgnoreCaseAndCategory_CategoryId for per-category duplicate detection.
RestroHub/src/main/java/com/restroly/qrmenu/food/service/FoodServiceImpl.java	Switches create/update duplicate checks from global name to category-scoped, with updated logs and error messages.

Comments suppressed due to low confidence (1)

RestroHub/src/main/java/com/restroly/qrmenu/category/service/CategoryServiceImpl.java:52

• The new category is built and saved without any association to the Menu identified by menuId. CategoryDTO.toEntity (called immediately below) does not set the menu field, and there is no menuRepository.findById(menuId) lookup or category.getMenu().add(menu) call here. As a result:

1. The menuId from the request is used only for the duplicate check and is silently discarded — the persisted category will not actually belong to any menu, so the very next createCategory call with the same name and menuId will again return false from existsByNameIgnoreCaseAndMenu_MenuId(...) and create another duplicate.
2. A non-existent menuId is never validated against MenuRepository, unlike the existing pattern in BranchServiceImpl.createBranch (RestroHub/src/main/java/com/restroly/qrmenu/branch/service/BranchServiceImpl.java:44-49) and MenuServiceImpl.createMenu (RestroHub/src/main/java/com/restroly/qrmenu/menu/service/MenuServiceImpl.java:46-49).

The create flow should look up the Menu by menuId (throwing ResourceNotFoundException if absent) and attach it to the new Category (e.g. category.getMenu().add(menu) / menu.getCategories().add(category)) before saving, otherwise the scoped duplicate validation cannot work.

		if(categoryRepository.existsByNameIgnoreCaseAndMenu_MenuId(
				requestDTO.getName(), requestDTO.getMenuId())) {
			log.warn("Category with name '{}' already exists in menu '{}'", requestDTO.getName(), requestDTO.getMenuId());
			throw new DuplicateResourceException("Category with name '" + requestDTO.getName() + "' already exists");
		}
		Category category = CategoryDTO.toEntity(
				CategoryDTO.builder()
						.name(requestDTO.getName())
						.description(requestDTO.getDescription())
						.isDelete(false) // default value
						.updatedDate(LocalDateTime.now())
						.build()
		);

		Category savedCategory = categoryRepository.save(category);
		log.info("Category created with ID: {}", savedCategory.getCategoryId());
		return CategoryResponseDTO.fromEntity(savedCategory);

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[iRahmanG]

Hi @rdodiya

I have fixed the changes as per review

• Category creation now validates menu existence and links the category to the menu.
• Food update now checks duplicates in the target category (from updateDTO if provided) and excludes the current foodId.

This resolves the duplicate validation issue mentioned in the review.

[rdodiya]

Hi @iRahmanG,
No need to check duplicate category names within a menu. Instead, validate duplicate category names within the same branch.

While creating categories, we are not assigning them to any menu. Categories are created independently first, and later menus are created which can contain multiple categories belonging to the same branch.

[iRahmanG]

Hi @rdodiya
I’ve updated the logic as per your feedback.

• Removed duplicate check within a menu
• Added duplicate validation at the branch level instead
• Categories are now created independently and linked to a branch, while menus can later include multiple categories from the same branch

Thanks for your feedback.