from typing import List, Optional

from sqlalchemy.orm import Session

from app.models.cart import CartItem
from app.schemas.cart import CartItemCreate, CartItemUpdate
from app.services.base import CRUDBase


class CartService(CRUDBase[CartItem, CartItemCreate, CartItemUpdate]):
    def get_cart_items(self, db: Session, *, user_id: int) -> List[CartItem]:
        return db.query(CartItem).filter(CartItem.user_id == user_id).all()

    def get_cart_item(
        self, db: Session, *, user_id: int, product_id: int
    ) -> Optional[CartItem]:
        return (
            db.query(CartItem)
            .filter(CartItem.user_id == user_id, CartItem.product_id == product_id)
            .first()
        )

    def add_item_to_cart(
        self, db: Session, *, obj_in: CartItemCreate, user_id: int, unit_price: float
    ) -> CartItem:
        db_obj = CartItem(
            user_id=user_id,
            product_id=obj_in.product_id,
            quantity=obj_in.quantity,
            unit_price=unit_price
        )
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def update_item_quantity(
        self, db: Session, *, db_obj: CartItem, quantity: int
    ) -> CartItem:
        db_obj.quantity = quantity
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    def clear_cart(self, db: Session, *, user_id: int) -> List[CartItem]:
        cart_items = self.get_cart_items(db, user_id=user_id)
        for item in cart_items:
            db.delete(item)
        db.commit()
        return cart_items

cart_service = CartService(CartItem)