symposion_app/registrasion/controllers/conditions.py

272 lines
9 KiB
Python
Raw Normal View History

import itertools
from collections import defaultdict
from collections import namedtuple
2016-01-22 05:01:30 +00:00
from django.db.models import Sum
from django.utils import timezone
from registrasion import models as rego
ConditionAndRemainder = namedtuple(
"ConditionAndRemainder",
(
"condition",
"remainder",
),
)
2016-01-22 05:01:30 +00:00
class ConditionController(object):
''' Base class for testing conditions that activate EnablingCondition
or Discount objects. '''
def __init__(self):
pass
@staticmethod
def for_condition(condition):
CONTROLLERS = {
2016-01-22 06:02:07 +00:00
rego.CategoryEnablingCondition: CategoryConditionController,
rego.IncludedProductDiscount: ProductConditionController,
rego.ProductEnablingCondition: ProductConditionController,
rego.TimeOrStockLimitDiscount:
TimeOrStockLimitDiscountController,
2016-01-22 06:02:07 +00:00
rego.TimeOrStockLimitEnablingCondition:
TimeOrStockLimitEnablingConditionController,
2016-01-22 06:02:07 +00:00
rego.VoucherDiscount: VoucherConditionController,
rego.VoucherEnablingCondition: VoucherConditionController,
2016-01-22 05:01:30 +00:00
}
try:
return CONTROLLERS[type(condition)](condition)
except KeyError:
return ConditionController()
@classmethod
def test_enabling_conditions(
cls, user, products=None, product_quantities=None):
''' Evaluates all of the enabling conditions on the given products.
If `product_quantities` is supplied, the condition is only met if it
will permit the sum of the product quantities for all of the products
it covers. Otherwise, it will be met if at least one item can be
accepted.
If all enabling conditions pass, an empty list is returned, otherwise
a list is returned containing all of the products that are *not
enabled*. '''
if products is not None and product_quantities is not None:
raise ValueError("Please specify only products or "
"product_quantities")
elif products is None:
products = set(i[0] for i in product_quantities)
2016-04-03 03:21:57 +00:00
quantities = dict((product, quantity)
for product, quantity in product_quantities)
elif product_quantities is None:
products = set(products)
quantities = {}
# Get the conditions covered by the products themselves
all_conditions = [
product.enablingconditionbase_set.select_subclasses() |
product.category.enablingconditionbase_set.select_subclasses()
for product in products
]
all_conditions = set(itertools.chain(*all_conditions))
# All mandatory conditions on a product need to be met
mandatory = defaultdict(lambda: True)
# At least one non-mandatory condition on a product must be met
# if there are no mandatory conditions
non_mandatory = defaultdict(lambda: False)
for condition in all_conditions:
cond = cls.for_condition(condition)
remainder = cond.user_quantity_remaining(user)
# Get all products covered by this condition, and the products
# from the categories covered by this condition
cond_products = condition.products.all()
from_category = rego.Product.objects.filter(
category__in=condition.categories.all(),
).all()
all_products = set(itertools.chain(cond_products, from_category))
# Remove the products that we aren't asking about
all_products = all_products & products
if quantities:
consumed = sum(quantities[i] for i in all_products)
else:
consumed = 1
met = consumed <= remainder
for product in all_products:
if condition.mandatory:
mandatory[product] &= met
else:
non_mandatory[product] |= met
valid = defaultdict(lambda: True)
for product in itertools.chain(mandatory, non_mandatory):
if product in mandatory:
# If there's a mandatory condition, all must be met
valid[product] = mandatory[product]
else:
# Otherwise, we need just one non-mandatory condition met
valid[product] = non_mandatory[product]
error_fields = [product for product in valid if not valid[product]]
return error_fields
def user_quantity_remaining(self, user):
''' Returns the number of items covered by this enabling condition the
user can add to the current cart. This default implementation returns
a big number if is_met() is true, otherwise 0.
Either this method, or is_met() must be overridden in subclasses.
'''
return 99999999 if self.is_met(user) else 0
def is_met(self, user):
''' Returns True if this enabling condition is met, otherwise returns
False.
Either this method, or user_quantity_remaining() must be overridden
in subclasses.
'''
return self.user_quantity_remaining(user) > 0
2016-01-22 05:01:30 +00:00
class CategoryConditionController(ConditionController):
def __init__(self, condition):
self.condition = condition
def is_met(self, user):
2016-01-22 05:01:30 +00:00
''' returns True if the user has a product from a category that invokes
this condition in one of their carts '''
carts = rego.Cart.objects.filter(user=user, released=False)
2016-01-22 05:01:30 +00:00
enabling_products = rego.Product.objects.filter(
2016-04-02 00:02:01 +00:00
category=self.condition.enabling_category,
)
products_count = rego.ProductItem.objects.filter(
cart__in=carts,
2016-04-02 00:02:01 +00:00
product__in=enabling_products,
).count()
return products_count > 0
2016-01-22 05:01:30 +00:00
class ProductConditionController(ConditionController):
''' Condition tests for ProductEnablingCondition and
IncludedProductDiscount. '''
def __init__(self, condition):
self.condition = condition
def is_met(self, user):
2016-01-22 05:01:30 +00:00
''' returns True if the user has a product that invokes this
condition in one of their carts '''
carts = rego.Cart.objects.filter(user=user, released=False)
products_count = rego.ProductItem.objects.filter(
cart__in=carts,
2016-04-02 00:02:01 +00:00
product__in=self.condition.enabling_products.all(),
).count()
return products_count > 0
2016-01-22 05:01:30 +00:00
class TimeOrStockLimitConditionController(ConditionController):
''' Common condition tests for TimeOrStockLimit EnablingCondition and
2016-01-22 05:01:30 +00:00
Discount.'''
def __init__(self, ceiling):
self.ceiling = ceiling
def user_quantity_remaining(self, user):
''' returns 0 if the date range is violated, otherwise, it will return
the quantity remaining under the stock limit. '''
2016-01-22 05:01:30 +00:00
# Test date range
if not self._test_date_range():
return 0
2016-01-22 05:01:30 +00:00
return self._get_remaining_stock(user)
2016-01-22 05:01:30 +00:00
def _test_date_range(self):
2016-01-22 05:01:30 +00:00
now = timezone.now()
if self.ceiling.start_time is not None:
if now < self.ceiling.start_time:
return False
if self.ceiling.end_time is not None:
if now > self.ceiling.end_time:
return False
return True
def _get_remaining_stock(self, user):
''' Returns the stock that remains under this ceiling, excluding the
user's current cart. '''
2016-01-22 05:01:30 +00:00
if self.ceiling.limit is None:
return 99999999
2016-01-22 05:01:30 +00:00
# We care about all reserved carts, but not the user's current cart
2016-01-22 05:01:30 +00:00
reserved_carts = rego.Cart.reserved_carts()
reserved_carts = reserved_carts.exclude(
user=user,
active=True,
)
items = self._items()
items = items.filter(cart__in=reserved_carts)
count = items.aggregate(Sum("quantity"))["quantity__sum"] or 0
return self.ceiling.limit - count
2016-04-03 03:21:57 +00:00
class TimeOrStockLimitEnablingConditionController(
TimeOrStockLimitConditionController):
def _items(self):
category_products = rego.Product.objects.filter(
category__in=self.ceiling.categories.all(),
)
products = self.ceiling.products.all() | category_products
2016-01-22 05:01:30 +00:00
product_items = rego.ProductItem.objects.filter(
product__in=products.all(),
2016-01-22 05:01:30 +00:00
)
return product_items
2016-01-22 05:01:30 +00:00
class TimeOrStockLimitDiscountController(TimeOrStockLimitConditionController):
def _items(self):
discount_items = rego.DiscountItem.objects.filter(
discount=self.ceiling,
)
return discount_items
2016-01-22 05:01:30 +00:00
class VoucherConditionController(ConditionController):
''' Condition test for VoucherEnablingCondition and VoucherDiscount.'''
def __init__(self, condition):
self.condition = condition
def is_met(self, user):
2016-01-22 05:01:30 +00:00
''' returns True if the user has the given voucher attached. '''
carts_count = rego.Cart.objects.filter(
2016-01-22 06:02:07 +00:00
user=user,
2016-04-02 00:02:01 +00:00
vouchers=self.condition.voucher,
).count()
return carts_count > 0