registrasion/controllers/item.py
def _items(self, cart_status, category=None):
        ''' Aggregates the items that this user has purchased.

        Arguments:
            cart_status (int or Iterable(int)): etc
            category (Optional[models.inventory.Category]): the category
                of items to restrict to.

        Returns:
            [ProductAndQuantity, ...]: A list of product-quantity pairs,
                aggregating like products from across multiple invoices.

        '''

        if not isinstance(cart_status, Iterable):
            cart_status = [cart_status]

        status_query = (
            Q(productitem__cart__status=status) for status in cart_status
        )

        in_cart = Q(productitem__cart__user=self.user)
        in_cart = in_cart & reduce(operator.__or__, status_query)

        quantities_in_cart = When(
            in_cart,
            then="productitem__quantity",
        )

        quantities_or_zero = Case(
            quantities_in_cart,
            default=Value(0),
        )

        products = inventory.Product.objects

        if category:
            products = products.filter(category=category)

        products = products.select_related("category")
        products = products.annotate(quantity=Sum(quantities_or_zero))
        products = products.filter(quantity__gt=0)

        out = []
        for prod in products:
            out.append(ProductAndQuantity(prod, prod.quantity))
        return out
def _items(self, cart_status, category=None):
        ''' Aggregates the items that this user has purchased.

        Arguments:
            cart_status (int or Iterable(int)): etc
            category (Optional[models.inventory.Category]): the category
                of items to restrict to.

        Returns:
            [ProductAndQuantity, ...]: A list of product-quantity pairs,
                aggregating like products from across multiple invoices.

        '''

        if not isinstance(cart_status, Iterable):
            cart_status = [cart_status]

        status_query = (
            Q(productitem__cart__status=status) for status in cart_status
        )

        in_cart = Q(productitem__cart__user=self.user)
        in_cart = in_cart & reduce(operator.__or__, status_query)

        quantities_in_cart = When(
            in_cart,
            then="productitem__quantity",
        )

        quantities_or_zero = Case(
            quantities_in_cart,
            default=Value(0),
        )

        products = inventory.Product.objects

        if category:
            products = products.filter(category=category)

        products = products.select_related("category")
        products = products.annotate(quantity=Sum(quantities_or_zero))
        products = products.filter(quantity__gt=0)

        out = []
        for prod in products:
            out.append(ProductAndQuantity(prod, prod.quantity))
        return out
Aggregates the items that this user has purchased.

        Arguments:
            cart_status (int or Iterable(int)): etc
            category (Optional[models.inventory.Category]): the category
                of items to restrict to.

        Returns:
            [ProductAndQuantity, ...]: A list of product-quantity pairs,
                aggregating like products from across multiple invoices.