From 6b2ab755616070cdda6c59c9b9f6db14d65260ad Mon Sep 17 00:00:00 2001
From: michael <michael.brehm@stud.hs-mannheim.de>
Date: Fri, 22 Nov 2024 17:46:32 +0100
Subject: [PATCH] add basic usecase layer

---
 src/use_cases/cart_repository_interface.py |  8 ++++++++
 src/use_cases/view_cart.py                 | 22 ++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 src/use_cases/cart_repository_interface.py
 create mode 100644 src/use_cases/view_cart.py

diff --git a/src/use_cases/cart_repository_interface.py b/src/use_cases/cart_repository_interface.py
new file mode 100644
index 0000000..5bf005a
--- /dev/null
+++ b/src/use_cases/cart_repository_interface.py
@@ -0,0 +1,8 @@
+from typing import Optional, List
+
+class CartRepositoryInterface:
+    def fetch_cart_by_user_id(self, user_id: int) -> Optional[List[dict]]:
+        """
+        Abstract method to fetch cart data by user ID.
+        """
+        raise NotImplementedError("fetch_cart_by_user_id must be implemented by a subclass")
diff --git a/src/use_cases/view_cart.py b/src/use_cases/view_cart.py
new file mode 100644
index 0000000..5618362
--- /dev/null
+++ b/src/use_cases/view_cart.py
@@ -0,0 +1,22 @@
+#python imports
+from typing import Optional
+
+#dependency imports
+from entities.cart import Cart, CartItem
+from interface_adapters.cart_repository import CartRepository
+
+class ViewCart:
+    def __init__(self, cart_repository: CartRepository):
+        self.cart_repository = cart_repository
+
+    def execute(self, user_id: int) -> Optional[Cart]:
+        """
+        Fetches the cart data from the repository, converts it to Cart entity.
+        """
+        cart_data = self.cart_repository.fetch_cart_by_user_id(user_id)
+        if not cart_data:
+            return None
+
+        # Convert raw data to domain entities
+        items = [CartItem(**item) for item in cart_data]
+        return Cart(items)
\ No newline at end of file