symposion_app/registrasion/controllers/product.py

90 lines
2.6 KiB
Python

import itertools
from django.db.models import Case
from django.db.models import F, Q
from django.db.models import Sum
from django.db.models import When
from django.db.models import Value
from registrasion.models import commerce
from registrasion.models import inventory
from .category import CategoryController
from .flag import FlagController
class ProductController(object):
def __init__(self, product):
self.product = product
@classmethod
def available_products(cls, user, category=None, products=None):
''' Returns a list of all of the products that are available per
flag conditions from the given categories. '''
if category is None and products is None:
raise ValueError("You must provide products or a category")
if category is not None:
all_products = inventory.Product.objects.filter(category=category)
all_products = all_products.select_related("category")
else:
all_products = []
if products is not None:
all_products = set(itertools.chain(all_products, products))
category_remainders = CategoryController.user_remainders(user)
product_remainders = ProductController.user_remainders(user)
passed_limits = set(
product
for product in all_products
if category_remainders[product.category.id] > 0
if product_remainders[product.id] > 0
)
failed_and_messages = FlagController.test_flags(
user, products=passed_limits
)
failed_conditions = set(i[0] for i in failed_and_messages)
out = list(passed_limits - failed_conditions)
out.sort(key=lambda product: product.order)
return out
@classmethod
def user_remainders(cls, user):
'''
Return:
Mapping[int->int]: A dictionary that maps the product ID to the
user's remainder for that product.
'''
products = inventory.Product.objects.all()
cart_filter = (
Q(productitem__cart__user=user) &
Q(productitem__cart__status=commerce.Cart.STATUS_PAID)
)
quantity = When(
cart_filter,
then='productitem__quantity'
)
quantity_or_zero = Case(
quantity,
default=Value(0),
)
remainder = Case(
When(limit_per_user=None, then=Value(99999999)),
default=F('limit_per_user') - Sum(quantity_or_zero),
)
products = products.annotate(remainder=remainder)
return dict((product.id, product.remainder) for product in products)