#python imports
from typing import Optional

#dependency imports
from entities.cart import Cart, CartItem
from use_cases.cart_repository_interface import CartRepositoryInterface

class ViewCart:
    def __init__(self, cart_repository: CartRepositoryInterface):
        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)