forked from uncloud/uncloud
485 lines
17 KiB
Python
485 lines
17 KiB
Python
from django.db import models
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from django.db.models import Q
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from django.contrib.auth import get_user_model
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from django.core.validators import MinValueValidator
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from django.utils.translation import gettext_lazy as _
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from django.utils import timezone
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from django.dispatch import receiver
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from django.core.exceptions import ObjectDoesNotExist
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import django.db.models.signals as signals
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import uuid
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from functools import reduce
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from math import ceil
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from datetime import timedelta
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from calendar import monthrange
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import uncloud_pay.stripe
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from uncloud_pay.helpers import beginning_of_month, end_of_month
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from decimal import Decimal
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# Define DecimalField properties, used to represent amounts of money.
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AMOUNT_MAX_DIGITS=10
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AMOUNT_DECIMALS=2
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# Used to generate bill due dates.
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BILL_PAYMENT_DELAY=timedelta(days=10)
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# See https://docs.djangoproject.com/en/dev/ref/models/fields/#field-choices-enum-types
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class RecurringPeriod(models.TextChoices):
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ONE_TIME = 'ONCE', _('Onetime')
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PER_YEAR = 'YEAR', _('Per Year')
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PER_MONTH = 'MONTH', _('Per Month')
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PER_MINUTE = 'MINUTE', _('Per Minute')
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PER_DAY = 'DAY', _('Per Day')
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PER_HOUR = 'HOUR', _('Per Hour')
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PER_SECOND = 'SECOND', _('Per Second')
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# See https://docs.djangoproject.com/en/dev/ref/models/fields/#field-choices-enum-types
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class ProductStatus(models.TextChoices):
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PENDING = 'PENDING', _('Pending')
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AWAITING_PAYMENT = 'AWAITING_PAYMENT', _('Awaiting payment')
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BEING_CREATED = 'BEING_CREATED', _('Being created')
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ACTIVE = 'ACTIVE', _('Active')
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DELETED = 'DELETED', _('Deleted')
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###
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# Users.
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def get_balance_for(user):
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bills = reduce(
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lambda acc, entry: acc + entry.total,
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Bill.objects.filter(owner=user),
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0)
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payments = reduce(
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lambda acc, entry: acc + entry.amount,
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Payment.objects.filter(owner=user),
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0)
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return payments - bills
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class StripeCustomer(models.Model):
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owner = models.OneToOneField( get_user_model(),
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primary_key=True,
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on_delete=models.CASCADE)
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stripe_id = models.CharField(max_length=32)
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###
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# Payments and Payment Methods.
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class Payment(models.Model):
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uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
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owner = models.ForeignKey(get_user_model(),
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on_delete=models.CASCADE)
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amount = models.DecimalField(
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default=0.0,
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max_digits=AMOUNT_MAX_DIGITS,
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decimal_places=AMOUNT_DECIMALS,
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validators=[MinValueValidator(0)])
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source = models.CharField(max_length=256,
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choices = (
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('wire', 'Wire Transfer'),
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('stripe', 'Stripe'),
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('voucher', 'Voucher'),
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('referral', 'Referral'),
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('unknown', 'Unknown')
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),
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default='unknown')
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timestamp = models.DateTimeField(editable=False, auto_now_add=True)
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# WIP prepaid and service activation logic by fnux.
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## We override save() in order to active products awaiting payment.
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#def save(self, *args, **kwargs):
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# # TODO: only run activation logic on creation, not on update.
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# unpaid_bills_before_payment = Bill.get_unpaid_for(self.owner)
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# super(Payment, self).save(*args, **kwargs) # Save payment in DB.
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# unpaid_bills_after_payment = Bill.get_unpaid_for(self.owner)
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# newly_paid_bills = list(
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# set(unpaid_bills_before_payment) - set(unpaid_bills_after_payment))
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# for bill in newly_paid_bills:
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# bill.activate_orders()
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class PaymentMethod(models.Model):
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uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
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owner = models.ForeignKey(get_user_model(),
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on_delete=models.CASCADE,
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editable=False)
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source = models.CharField(max_length=256,
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choices = (
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('stripe', 'Stripe'),
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('unknown', 'Unknown'),
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),
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default='stripe')
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description = models.TextField()
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primary = models.BooleanField(default=True)
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# Only used for "Stripe" source
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stripe_payment_method_id = models.CharField(max_length=32, blank=True, null=True)
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stripe_setup_intent_id = models.CharField(max_length=32, blank=True, null=True)
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@property
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def stripe_card_last4(self):
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if self.source == 'stripe' and self.active:
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payment_method = uncloud_pay.stripe.get_payment_method(
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self.stripe_payment_method_id)
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return payment_method.card.last4
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else:
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return None
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@property
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def active(self):
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if self.source == 'stripe' and self.stripe_payment_method_id != None:
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return True
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else:
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return False
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def charge(self, amount):
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if not self.active:
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raise Exception('This payment method is inactive.')
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if amount < 0: # Make sure we don't charge negative amount by errors...
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raise Exception('Cannot charge negative amount.')
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if self.source == 'stripe':
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stripe_customer = StripeCustomer.objects.get(owner=self.owner).stripe_id
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stripe_payment = uncloud_pay.stripe.charge_customer(
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amount, stripe_customer, self.stripe_payment_method_id)
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if 'paid' in stripe_payment and stripe_payment['paid'] == False:
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raise Exception(stripe_payment['error'])
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else:
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payment = Payment.objects.create(
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owner=self.owner, source=self.source, amount=amount)
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return payment
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else:
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raise Exception('This payment method is unsupported/cannot be charged.')
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def get_primary_for(user):
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methods = PaymentMethod.objects.filter(owner=user)
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for method in methods:
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# Do we want to do something with non-primary method?
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if method.active and method.primary:
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return method
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return None
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class Meta:
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# TODO: limit to one primary method per user.
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# unique_together is no good since it won't allow more than one
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# non-primary method.
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pass
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###
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# Bills.
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class Bill(models.Model):
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uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
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owner = models.ForeignKey(get_user_model(),
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on_delete=models.CASCADE)
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creation_date = models.DateTimeField(auto_now_add=True)
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starting_date = models.DateTimeField()
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ending_date = models.DateTimeField()
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due_date = models.DateField()
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valid = models.BooleanField(default=True)
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@property
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def reference(self):
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return "{}-{}".format(
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self.owner.username,
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self.creation_date.strftime("%Y-%m-%d-%H%M"))
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@property
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def records(self):
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bill_records = []
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orders = Order.objects.filter(bill=self)
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for order in orders:
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for order_record in order.records:
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bill_record = BillRecord(self, order_record)
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bill_records.append(bill_record)
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return bill_records
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@property
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def total(self):
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return reduce(lambda acc, record: acc + record.amount, self.records, 0)
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@property
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def final(self):
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# A bill is final when its ending date is passed.
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return self.ending_date < timezone.now()
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@staticmethod
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def generate_for(year, month, user):
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# /!\ We exclusively work on the specified year and month.
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# Default values for next bill (if any). Only saved at the end of
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# this method, if relevant.
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next_bill = Bill(owner=user,
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starting_date=beginning_of_month(year, month),
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ending_date=end_of_month(year, month),
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creation_date=timezone.now(),
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due_date=timezone.now() + BILL_PAYMENT_DELAY)
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# Select all orders active on the request period.
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orders = Order.objects.filter(
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Q(ending_date__gt=next_bill.starting_date) | Q(ending_date__isnull=True),
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owner=user)
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# Check if there is already a bill covering the order and period pair:
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# * Get latest bill by ending_date: previous_bill.ending_date
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# * If previous_bill.ending_date is before next_bill.ending_date, a new
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# bill has to be generated.
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unpaid_orders = []
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for order in orders:
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try:
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previous_bill = order.bill.latest('ending_date')
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except ObjectDoesNotExist:
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previous_bill = None
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if previous_bill == None or previous_bill.ending_date < next_bill.ending_date:
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unpaid_orders.append(order)
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# Commit next_bill if it there are 'unpaid' orders.
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if len(unpaid_orders) > 0:
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next_bill.save()
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# It is not possible to register many-to-many relationship before
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# the two end-objects are saved in database.
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for order in unpaid_orders:
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order.bill.add(next_bill)
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# TODO: use logger.
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print("Generated bill {} (amount: {}) for user {}."
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.format(next_bill.uuid, next_bill.total, user))
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return next_bill
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# Return None if no bill was created.
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return None
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@staticmethod
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def get_unpaid_for(user):
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balance = get_balance_for(user)
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unpaid_bills = []
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# No unpaid bill if balance is positive.
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if balance >= 0:
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return []
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else:
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bills = Bill.objects.filter(
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owner=user,
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due_date__lt=timezone.now()
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).order_by('-creation_date')
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# Amount to be paid by the customer.
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unpaid_balance = abs(balance)
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for bill in bills:
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if unpaid_balance < 0:
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break
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unpaid_balance -= bill.amount
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unpaid_bills.append(bill)
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return unpaid_bills
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@staticmethod
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def get_overdue_for(user):
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unpaid_bills = Bill.get_unpaid_for(user)
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return list(filter(lambda bill: bill.due_date > timezone.now(), unpaid_bills))
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class BillRecord():
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"""
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Entry of a bill, dynamically generated from order records.
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"""
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def __init__(self, bill, order_record):
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self.bill = bill
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self.order = order_record.order
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self.recurring_price = order_record.recurring_price
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self.recurring_period = order_record.recurring_period
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self.description = order_record.description
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if self.order.starting_date > self.bill.starting_date:
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self.one_time_price = order_record.one_time_price
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else:
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self.one_time_price = 0
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@property
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def recurring_count(self):
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# Compute billing delta.
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billed_until = self.bill.ending_date
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if self.order.ending_date != None and self.order.ending_date < self.order.ending_date:
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billed_until = self.order.ending_date
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billed_from = self.bill.starting_date
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if self.order.starting_date > self.bill.starting_date:
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billed_from = self.order.starting_date
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if billed_from > billed_until:
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# TODO: think about and check edges cases. This should not be
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# possible.
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raise Exception('Impossible billing delta!')
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billed_delta = billed_until - billed_from
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# TODO: refactor this thing?
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# TODO: weekly
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# TODO: yearly
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if self.recurring_period == RecurringPeriod.PER_MONTH:
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days = ceil(billed_delta / timedelta(days=1))
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# XXX: we assume monthly bills for now.
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if (self.bill.starting_date.year != self.bill.starting_date.year or
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self.bill.starting_date.month != self.bill.ending_date.month):
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raise Exception('Bill {} covers more than one month. Cannot bill PER_MONTH.'.
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format(self.bill.uuid))
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# XXX: minumal length of monthly order is to be enforced somewhere else.
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(_, days_in_month) = monthrange(
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self.bill.starting_date.year,
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self.bill.starting_date.month)
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return Decimal(days / days_in_month)
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elif self.recurring_period == RecurringPeriod.PER_DAY:
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days = ceil(billed_delta / timedelta(days=1))
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return Decimal(days)
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elif self.recurring_period == RecurringPeriod.PER_HOUR:
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hours = ceil(billed_delta / timedelta(hours=1))
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return Decimal(hours)
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elif self.recurring_period == RecurringPeriod.PER_SECOND:
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seconds = ceil(billed_delta / timedelta(seconds=1))
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return Decimal(seconds)
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elif self.recurring_period == RecurringPeriod.ONE_TIME:
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return Decimal(0)
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else:
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raise Exception('Unsupported recurring period: {}.'.
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format(record.recurring_period))
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@property
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def amount(self):
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return self.recurring_price * self.recurring_count + self.one_time_price
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###
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# Orders.
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# Order are assumed IMMUTABLE and used as SOURCE OF TRUST for generating
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# bills. Do **NOT** mutate then!
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class Order(models.Model):
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uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
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owner = models.ForeignKey(get_user_model(),
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on_delete=models.CASCADE,
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editable=False)
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# TODO: enforce ending_date - starting_date to be larger than recurring_period.
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creation_date = models.DateTimeField(auto_now_add=True)
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starting_date = models.DateTimeField(auto_now_add=True)
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ending_date = models.DateTimeField(blank=True,
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null=True)
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bill = models.ManyToManyField(Bill,
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editable=False,
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blank=True)
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recurring_period = models.CharField(max_length=32,
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choices = RecurringPeriod.choices,
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default = RecurringPeriod.PER_MONTH)
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@property
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def records(self):
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return OrderRecord.objects.filter(order=self)
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@property
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def one_time_price(self):
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return reduce(lambda acc, record: acc + record.one_time_price, self.records, 0)
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@property
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def recurring_price(self):
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return reduce(lambda acc, record: acc + record.recurring_price, self.records, 0)
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def add_record(self, one_time_price, recurring_price, description):
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OrderRecord.objects.create(order=self,
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one_time_price=one_time_price,
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recurring_price=recurring_price,
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description=description)
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class OrderRecord(models.Model):
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"""
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Order records store billing informations for products: the actual product
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might be mutated and/or moved to another order but we do not want to loose
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the details of old orders.
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Used as source of trust to dynamically generate bill entries.
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"""
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order = models.ForeignKey(Order, on_delete=models.CASCADE)
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one_time_price = models.DecimalField(default=0.0,
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max_digits=AMOUNT_MAX_DIGITS,
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decimal_places=AMOUNT_DECIMALS,
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validators=[MinValueValidator(0)])
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recurring_price = models.DecimalField(default=0.0,
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max_digits=AMOUNT_MAX_DIGITS,
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decimal_places=AMOUNT_DECIMALS,
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validators=[MinValueValidator(0)])
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description = models.TextField()
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@property
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def recurring_period(self):
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return self.order.recurring_period
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@property
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def starting_date(self):
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return self.order.starting_date
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@property
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def ending_date(self):
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return self.order.ending_date
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###
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# Products
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# Abstract (= no database representation) class used as parent for products
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# (e.g. uncloud_vm.models.VMProduct).
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class Product(models.Model):
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uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
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owner = models.ForeignKey(get_user_model(),
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on_delete=models.CASCADE,
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editable=False)
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description = ""
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status = models.CharField(max_length=32,
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choices=ProductStatus.choices,
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default=ProductStatus.PENDING)
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order = models.ForeignKey(Order,
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on_delete=models.CASCADE,
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editable=False,
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null=True)
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@property
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def recurring_price(self, recurring_period=RecurringPeriod.PER_MONTH):
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pass # To be implemented in child.
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@property
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def one_time_price(self):
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return 0
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@property
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def recurring_period(self):
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return self.order.recurring_period
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@staticmethod
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def allowed_recurring_periods():
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return RecurringPeriod.choices
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class Meta:
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abstract = True
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