membersystem/src/membership/models.py

95 lines
2.7 KiB
Python

from django.contrib.postgres.constraints import ExclusionConstraint
from django.contrib.postgres.fields import DateRangeField
from django.contrib.postgres.fields import RangeOperators
from django.db import models
from django.utils import timezone
from django.utils.translation import gettext as _
from utils.mixins import CreatedModifiedAbstract
class SubscriptionPeriod(CreatedModifiedAbstract):
"""
Denotes a period for which members should pay their membership fee for.
"""
period = DateRangeField(verbose_name=_("period"))
class Meta:
constraints = [
ExclusionConstraint(
name="exclude_overlapping_periods",
expressions=[
("period", RangeOperators.OVERLAPS),
],
),
]
def __str__(self):
return (
f"{self.period.lower} - {self.period.upper or _('next general assembly')}"
)
class Membership(CreatedModifiedAbstract):
"""
Tracks that a user has membership of a given type for a given period.
"""
class QuerySet(models.QuerySet):
def for_user(self, user):
return self.filter(user=user)
def _current(self):
return self.filter(period__period__contains=timezone.now())
def current(self) -> "Membership | None":
try:
return self._current().get()
except self.model.DoesNotExist:
return None
def previous(self) -> list["Membership"]:
# A naïve way to get previous by just excluding the current. This
# means that there must be some protection against "future"
# memberships.
return list(self.all().difference(self._current()))
objects = QuerySet.as_manager()
class Meta:
verbose_name = _("membership")
verbose_name_plural = _("memberships")
user = models.ForeignKey("auth.User", on_delete=models.PROTECT)
membership_type = models.ForeignKey(
"membership.MembershipType",
related_name="memberships",
verbose_name=_("subscription type"),
on_delete=models.PROTECT,
)
period = models.ForeignKey(
"membership.SubscriptionPeriod", on_delete=models.PROTECT
)
def __str__(self):
return f"{self.user} - {self.period}"
class MembershipType(CreatedModifiedAbstract):
"""
Models membership types. Currently only a name, but will in the future
possibly contain more information like fees.
"""
class Meta:
verbose_name = _("membership type")
verbose_name_plural = _("membership types")
name = models.CharField(verbose_name=_("name"), max_length=64)
def __str__(self):
return self.name