symposion_app/registrasion/controllers/product.py

99 lines
3.1 KiB
Python

import itertools
from collections import namedtuple
from django.db.models import F, Q
from registrasion import models as rego
from conditions import ConditionController
DiscountEnabler = namedtuple("DiscountEnabler", ("discount", "condition", "value"))
class ProductController(object):
def __init__(self, product):
self.product = product
def user_can_add_within_limit(self, user, quantity):
''' 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)
items = rego.ProductItem.objects.filter(product=self.product, cart=carts)
count = 0
for item in items:
count += item.quantity
if quantity + count > self.product.limit_per_user:
return False
else:
return True
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
def get_enabler(self, condition):
if condition.percentage is not None:
value = condition.percentage * self.product.price
else:
value = condition.price
return DiscountEnabler(
discount=condition.discount,
condition=condition,
value=value
)
def available_discounts(self, user):
''' Returns the set of available discounts for this user, for this
product. '''
product_discounts = rego.DiscountForProduct.objects.filter(
product=self.product)
category_discounts = rego.DiscountForCategory.objects.filter(
category=self.product.category
)
potential_discounts = set(itertools.chain(
(self.get_enabler(i) for i in product_discounts),
(self.get_enabler(i) for i in category_discounts),
))
discounts = []
for discount in potential_discounts:
real_discount = rego.DiscountBase.objects.get_subclass(pk=discount.discount.pk)
cond = ConditionController.for_condition(real_discount)
if cond.is_met(user, 0):
discounts.append(discount)
return discounts