symposion_app/registrasion/controllers/item.py
2016-09-02 15:57:20 +10:00

95 lines
2.5 KiB
Python

''' NEEDS TESTS '''
from registrasion.models import commerce
from registrasion.models import inventory
from collections import namedtuple
from django.db.models import Case
from django.db.models import Q
from django.db.models import Sum
from django.db.models import When
from django.db.models import Value
_ProductAndQuantity = namedtuple("ProductAndQuantity", ["product", "quantity"])
class ProductAndQuantity(_ProductAndQuantity):
''' Class that holds a product and a quantity.
Attributes:
product (models.inventory.Product)
quantity (int)
'''
pass
class ItemController(object):
def __init__(self, user):
self.user = user
def items_purchased(self, category=None):
''' Aggregates the items that this user has purchased.
Arguments:
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.
'''
in_cart = (
Q(productitem__cart__user=self.user) &
Q(productitem__cart__status=commerce.Cart.STATUS_PAID)
)
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_pending(self):
''' Gets all of the items that the user has reserved, but has not yet
paid for.
Returns:
[ProductAndQuantity, ...]: A list of product-quantity pairs for the
items that the user has not yet paid for.
'''
all_items = commerce.ProductItem.objects.filter(
cart__user=self.user,
cart__status=commerce.Cart.STATUS_ACTIVE,
).select_related(
"product",
"product__category",
).order_by(
"product__category__order",
"product__order",
)
return all_items