Unification of pagination, admins control and more

services/catalogue.py

@@ -0,0 +1,54 @@
+from typing import Union, Optional
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from dto.catalogue import CatalogueType, CatalogueView
+from repositories import ProductRepository, CategoriesRepository
+from config import PAGE_SIZE
+
+
+class CatalogueService:
+    def __init__(
+        self, product_repo: ProductRepository, categories_repo: CategoriesRepository
+    ) -> None:
+        self.product_repo = product_repo
+        self.categories_repo = categories_repo
+
+    async def build_category_view(
+        self, session: AsyncSession, cat_id: Optional[Union[int, str]], page: int = 0
+    ) -> CatalogueView:
+        cat_id = (
+            int(cat_id)
+            if isinstance(cat_id, (int, str)) and str(cat_id).isdigit()
+            else None
+        )
+
+        view = CatalogueView(page=page)
+        children = await self.categories_repo.get_categories_by_parent_id(
+            session, cat_id
+        )
+        category = await self.categories_repo.get_category_by_id(session, cat_id)
+
+        if not category:  # Root category
+            view.category = "root"
+            view.show_menu = True
+        else:  # Subcategories
+            view.category = cat_id
+            view.parent_id = category.parent_id or "root"
+
+        if not children:  # Products
+            view.view_type = CatalogueType.PRODUCTS
+            products = await self.product_repo.get_product_by_category(
+                session, cat_id, limit=PAGE_SIZE + 1, offset=view.page * PAGE_SIZE
+            )
+
+            if not products:
+                view.view_type = CatalogueType.EMPTY
+
+            view.products = products[:PAGE_SIZE]
+            view.has_next = len(products) > PAGE_SIZE
+            return view
+
+        view.view_type = CatalogueType.CATEGORIES
+        view.children = children[:PAGE_SIZE]
+
+        return view