symposion_app/registrasion/controllers/product.py

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import itertools
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from django.db.models import Q
from django.db.models import Sum
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from registrasion import models as rego
from conditions import ConditionController
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
enabling conditions from the given categories.
TODO: refactor so that all conditions are tested here and
can_add_with_enabling_conditions calls this method. '''
if category is None and products is None:
raise ValueError("You must provide products or a category")
if category is not None:
all_products = rego.Product.objects.filter(category=category)
else:
all_products = []
if products is not None:
all_products = itertools.chain(all_products, products)
out = [
product
for product in all_products
if cls(product).user_can_add_within_limit(user, 1, past_carts=True)
if cls(product).can_add_with_enabling_conditions(user, 0)
]
out.sort(key=lambda product: product.order)
return out
def user_can_add_within_limit(self, user, quantity, past_carts=False):
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''' Return true if the user is able to add _quantity_ to their count of
this Product without exceeding _limit_per_user_.'''
carts = rego.Cart.objects.filter(
user=user,
released=False,
)
if past_carts:
carts = carts.filter(active=False)
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items = rego.ProductItem.objects.filter(
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cart__in=carts,
)
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prod_items = items.filter(product=self.product)
cat_items = items.filter(product__category=self.product.category)
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prod_count = prod_items.aggregate(Sum("quantity"))["quantity__sum"]
cat_count = cat_items.aggregate(Sum("quantity"))["quantity__sum"]
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if prod_count is None:
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prod_count = 0
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if cat_count is None:
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cat_count = 0
prod_limit = self.product.limit_per_user
prod_met = prod_limit is None or quantity + prod_count <= prod_limit
cat_limit = self.product.category.limit_per_user
cat_met = cat_limit is None or quantity + cat_count <= cat_limit
if prod_met and cat_met:
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return True
else:
return False
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def can_add_with_enabling_conditions(self, user, quantity):
''' Returns true if the user is able to add _quantity_ to their count
of this Product without exceeding the ceilings the product is attached
to. '''
conditions = rego.EnablingConditionBase.objects.filter(
Q(products=self.product) | Q(categories=self.product.category)
).select_subclasses()
mandatory_violated = False
non_mandatory_met = False
for condition in conditions:
cond = ConditionController.for_condition(condition)
met = cond.is_met(user, quantity)
if condition.mandatory and not met:
mandatory_violated = True
break
if met:
non_mandatory_met = True
if mandatory_violated:
# All mandatory conditions must be met
return False
if len(conditions) > 0 and not non_mandatory_met:
# If there's any non-mandatory conditions, one must be met
return False
return True