def _add(self, cart: Cart, product: Product, quantity: int):
for product_item in product.items.filter(
quantity__gt=0,
latest_delivery_date__gt=datetime.datetime.utcnow().date(
)).order_by("latest_delivery_date"):
item_quantity = (quantity if quantity <= product_item.quantity else
product_item.quantity)
cart_item, created = CartItem.objects.get_or_create(
cart=cart,
product=product,
latest_delivery_date=product_item.latest_delivery_date,
defaults={
"quantity": item_quantity,
"delivery_option":
product.first_available_delivery_option(),
},
)
if not created:
cart_item.quantity += item_quantity
cart_item.save()
product_item.quantity -= item_quantity
if product_item.quantity == 0:
product_item.delete()
else:
product_item.save()
quantity -= item_quantity
if quantity == 0:
break
# TODO: bulk save?
return quantity
