import itertools
from . import inventory
from django.core.exceptions import ValidationError
from django.db import models
from django.utils.encoding import python_2_unicode_compatible
from django.utils.translation import ugettext_lazy as _
from model_utils.managers import InheritanceManager
# Product Modifiers
@python_2_unicode_compatible
class DiscountBase(models.Model):
''' Base class for discounts. Each subclass has controller code that
determines whether or not the given discount is available to be added to
the current cart. '''
''' Base class for discounts. This class is subclassed with special
attributes which are used to determine whether or not the given discount
is available to be added to the current cart.
Attributes:
description (str): Display text that appears on the attendee's Invoice
when the discount is applied to a Product on that invoice.
'''
class Meta:
app_label = "registrasion"
objects = InheritanceManager()
def __str__(self):
return "Discount: " + self.description
def effects(self):
''' Returns all of the effects of this discount. '''
products = self.discountforproduct_set.all()
categories = self.discountforcategory_set.all()
return itertools.chain(products, categories)
description = models.CharField(
max_length=255,
verbose_name=_("Description"),
help_text=_("A description of this discount. This will be included on "
"invoices where this discount is applied."),
)
class DiscountForProduct(models.Model):
''' Represents a discount on an individual product. Each Discount can
contain multiple products and categories. Discounts can either be a
percentage or a fixed amount, but not both. '''
percentage or a fixed amount, but not both.
product (inventory.Product): The product that this discount line will
apply to.
percentage (Decimal): The percentage discount that will be *taken off*
this product if this discount applies.
price (Decimal): The currency value that will be *taken off* this
product if this discount applies.
quantity (int): The number of times that each user may apply this
discount line. This applies across every valid Invoice that
the user has.
if self.percentage:
return "%s%% off %s" % (self.percentage, self.product)
elif self.price:
return "$%s off %s" % (self.price, self.product)
def clean(self):
if self.percentage is None and self.price is None:
raise ValidationError(
_("Discount must have a percentage or a price."))
elif self.percentage is not None and self.price is not None:
_("Discount may only have a percentage or only a price."))
prods = DiscountForProduct.objects.filter(
discount=self.discount,
product=self.product)
cats = DiscountForCategory.objects.filter(
category=self.product.category)
if len(prods) > 1:
_("You may only have one discount line per product"))
if len(cats) != 0:
_("You may only have one discount for "
"a product or its category"))
discount = models.ForeignKey(DiscountBase, on_delete=models.CASCADE)
product = models.ForeignKey(inventory.Product, on_delete=models.CASCADE)
percentage = models.DecimalField(
max_digits=4, decimal_places=1, null=True, blank=True)
price = models.DecimalField(
max_digits=8, decimal_places=2, null=True, blank=True)
quantity = models.PositiveIntegerField()
class DiscountForCategory(models.Model):
''' Represents a discount for a category of products. Each discount can
contain multiple products. Category discounts can only be a percentage. '''
contain multiple products. Category discounts can only be a percentage.
category (inventory.Category): The category whose products that this
discount line will apply to.
a product if this discount applies.
discount line. This applies across every valid Invoice that the
user has.
return "%s%% off %s" % (self.percentage, self.category)
product__category=self.category)
category=self.category)
if len(prods) != 0:
if len(cats) > 1:
_("You may only have one discount line per category"))
category = models.ForeignKey(inventory.Category, on_delete=models.CASCADE)
max_digits=4,
decimal_places=1)
class TimeOrStockLimitDiscount(DiscountBase):
''' Discounts that are generally available, but are limited by timespan or
usage count. This is for e.g. Early Bird discounts. '''
usage count. This is for e.g. Early Bird discounts.
start_time (Optional[datetime]): When the discount should start being
offered.
end_time (Optional[datetime]): When the discount should stop being
limit (Optional[int]): How many times the discount is allowed to be
applied -- to all users.
verbose_name = _("discount (time/stock limit)")
verbose_name_plural = _("discounts (time/stock limit)")
start_time = models.DateTimeField(
null=True,
blank=True,
verbose_name=_("Start time"),
help_text=_("This discount will only be available after this time."),
end_time = models.DateTimeField(
verbose_name=_("End time"),
help_text=_("This discount will only be available before this time."),
limit = models.PositiveIntegerField(
verbose_name=_("Limit"),
help_text=_("This discount may only be applied this many times."),
class VoucherDiscount(DiscountBase):
''' Discounts that are enabled when a voucher code is in the current
cart. '''
cart. These are normally configured in the Admin page at the same time as
creating a Voucher object.
voucher (inventory.Voucher): The voucher that enables this discount.
verbose_name = _("discount (enabled by voucher)")
verbose_name_plural = _("discounts (enabled by voucher)")
voucher = models.OneToOneField(
inventory.Voucher,
on_delete=models.CASCADE,
verbose_name=_("Voucher"),
db_index=True,
class IncludedProductDiscount(DiscountBase):
''' Discounts that are enabled because another product has been purchased.
e.g. A conference ticket includes a free t-shirt. '''
e.g. A conference ticket includes a free t-shirt.
enabling_products ([inventory.Product, ...]): The products that enable
the discount.
verbose_name = _("discount (product inclusions)")
verbose_name_plural = _("discounts (product inclusions)")
enabling_products = models.ManyToManyField(
inventory.Product,
verbose_name=_("Including product"),
help_text=_("If one of these products are purchased, the discounts "
"below will be enabled."),
class RoleDiscount(object):
''' Discounts that are enabled because the active user has a specific
role. This is for e.g. volunteers who can get a discount ticket. '''
# TODO: implement RoleDiscount
pass
class FlagBase(models.Model):
''' This defines a condition which allows products or categories to
be made visible, or be prevented from being visible.
The various subclasses of this can define the conditions that enable
or disable products, by the following rules:
description (str): A human-readable description that is used to
identify the flag to staff in the admin interface. It's not seen
anywhere else in Registrasion.
condition (int): This determines the effect of this flag's condition
being met. There are two types of condition:
``ENABLE_IF_TRUE`` conditions switch on the products and
categories included under this flag if *any* such condition is met.
``DISABLE_IF_FALSE`` conditions *switch off* the products and
categories included under this flag is any such condition
*is not* met.
If there is at least one 'disable if false' flag defined on a product or
category, all such flag conditions must be met. If there is at least one
'enable if true' flag, at least one such condition must be met.
If you have both types of conditions attached to a Product, every
``DISABLE_IF_FALSE`` condition must be met, along with one
``ENABLE_IF_TRUE`` condition.
If both types of conditions exist on a product, both of these rules apply.
products ([inventory.Product, ...]):
The Products affected by this flag.
categories ([inventory.Category, ...]):
The Categories whose Products are affected by this flag.
# TODO: make concrete once https://code.djangoproject.com/ticket/26488
# is solved.
abstract = True
DISABLE_IF_FALSE = 1
ENABLE_IF_TRUE = 2
return self.description
''' Returns all of the items affected by this condition. '''
return itertools.chain(self.products.all(), self.categories.all())
@property
def is_disable_if_false(self):
return self.condition == FlagBase.DISABLE_IF_FALSE
def is_enable_if_true(self):
return self.condition == FlagBase.ENABLE_IF_TRUE
@@ -250,98 +325,122 @@ class FlagBase(models.Model):
categories = models.ManyToManyField(
inventory.Category,
help_text=_("Categories whose products are affected by this flag's "
"condition."
),
related_name="flagbase_set",
class EnablingConditionBase(FlagBase):
''' Reifies the abstract FlagBase. This is necessary because django
prevents renaming base classes in migrations. '''
# TODO: remove this, and make subclasses subclass FlagBase once
# https://code.djangoproject.com/ticket/26488 is solved.
class TimeOrStockLimitFlag(EnablingConditionBase):
''' Registration product ceilings '''
''' Product groupings that can be used to enable a product during a
specific date range, or when fewer than a limit of products have been
sold.
start_time (Optional[datetime]): This condition is only met after this
time.
end_time (Optional[datetime]): This condition is only met before this
limit (Optional[int]): The number of products that *all users* can
purchase under this limit, regardless of their per-user limits.
verbose_name = _("flag (time/stock limit)")
verbose_name_plural = _("flags (time/stock limit)")
help_text=_("Products included in this condition will only be "
"available after this time."),
"available before this time."),
help_text=_("The number of items under this grouping that can be "
"purchased."),
class ProductFlag(EnablingConditionBase):
''' The condition is met because a specific product is purchased. '''
''' The condition is met because a specific product is purchased.
enabling_products ([inventory.Product, ...]): The products that cause this
condition to be met.
verbose_name = _("flag (dependency on product)")
verbose_name_plural = _("flags (dependency on product)")
return "Enabled by products: " + str(self.enabling_products.all())
help_text=_("If one of these products are purchased, this condition "
"is met."),
class CategoryFlag(EnablingConditionBase):
''' The condition is met because a product in a particular product is
purchased. '''
purchased.
enabling_category (inventory.Category): The category that causes this
verbose_name = _("flag (dependency on product from category)")
verbose_name_plural = _("flags (dependency on product from category)")
return "Enabled by product in category: " + str(self.enabling_category)
enabling_category = models.ForeignKey(
help_text=_("If a product from this category is purchased, this "
"condition is met."),
class VoucherFlag(EnablingConditionBase):
''' The condition is met because a Voucher is present. This is for e.g.
enabling sponsor tickets. '''
verbose_name = _("flag (dependency on voucher)")