Product rendering, cart functionality

services/orders.py

@@ -1,11 +1,117 @@
+import logging
 from sqlalchemy.ext.asyncio import AsyncSession
+from db.models.orders import OrderStatus
+from repositories.order_items import OrderItemRepository
 from repositories.orders import OrderRepository
 
+logger = logging.getLogger(__name__)
+
+
+class OrderServiceException(Exception): ...
+
 
 class OrderService:
-    def __init__(self, order_repo: OrderRepository):
+    def __init__(
+        self, order_repo: OrderRepository, order_items_repo: OrderItemRepository
+    ):
         self.order_repo = order_repo
+        self.order_items_repo = order_items_repo
 
-    async def get_order_count(self, session: AsyncSession, user_id: int) -> int:
-        orders = await self.order_repo.get_orders_by_user(session, user_id)
+    async def get_order_count(self, session: AsyncSession, customer: int) -> int:
+        orders = await self.order_repo.get_orders_by_user(session, customer)
         return len(orders)
+
+    async def add_to_cart(
+        self,
+        session: AsyncSession,
+        *,
+        customer: int,
+        product_id: int,
+        quantity: int = 1,
+    ) -> int:
+        order = await self.order_repo.get_draft_order_by_user(session, customer)
+
+        if not order:
+            order = await self.order_repo.create_order(
+                session, customer, OrderStatus.DRAFT
+            )
+
+        order_item = await self.order_items_repo.get_item_by_order_and_product(
+            session, order_id=order.id, product_id=product_id
+        )
+
+        if not order_item:
+            order_item = await self.order_items_repo.create_order_item(
+                session, order_id=order.id, product_id=product_id, quantity=quantity
+            )
+        else:
+            await self.order_items_repo.update_order_item_quantity(
+                session, order_item.id, quantity=order_item.quantity + quantity
+            )
+
+        return order_item.quantity + quantity
+
+    async def remove_from_cart(
+        self,
+        session: AsyncSession,
+        *,
+        customer: int,
+        product_id: int,
+        quantity: int = 1,
+    ) -> int:
+        order = await self.order_repo.get_draft_order_by_user(session, customer)
+
+        if not order:
+            raise OrderServiceException(
+                "attempt of removing product from non-existing cart, potential callback_query exploit, ignoring..."
+            )
+
+        order_item = await self.order_items_repo.get_item_by_order_and_product(
+            session, order_id=order.id, product_id=product_id
+        )
+
+        if not order_item:
+            raise OrderServiceException(
+                "attempt of decreasing quantity of non-existing order_item, potential callback_query exploit, ignoring..."
+            )
+
+        new_quantity = max(0, order_item.quantity - quantity)
+        await self.order_items_repo.update_order_item_quantity(
+            session, order_item_id=order_item.id, quantity=new_quantity
+        )
+
+        return new_quantity
+
+    async def get_cart_product_amount(
+        self, session: AsyncSession, *, customer: int, product_id: int
+    ) -> int:
+        order = await self.order_repo.get_draft_order_by_user(session, customer)
+
+        if not order:
+            return 0
+
+        order_item = await self.order_items_repo.get_item_by_order_and_product(
+            session, order_id=order.id, product_id=product_id
+        )
+        return order_item.quantity
+
+    async def clear_cart_item(self, session, *, customer: int, product_id: int) -> None:
+        order = await self.order_repo.get_draft_order_by_user(session, customer)
+
+        if not order:
+            raise OrderServiceException(
+                "attempt of clearing a non-existing cart, potential callback_query exploit, ignoring..."
+            )
+
+        order_item = await self.order_items_repo.get_item_by_order_and_product(
+            session, order_id=order.id, product_id=product_id
+        )
+
+        if not order_item:
+            raise OrderServiceException(
+                "attempt of clearing an order_item that isn't in a cart, potential callback_query exploit, ignoring..."
+            )
+
+        await self.order_items_repo.update_order_item_quantity(
+            session, order_item_id=order_item.id, quantity=0
+        )