uncloud/uncloud/uncloud_pay/models.py

282 lines
10 KiB
Python

from django.db import models
from functools import reduce
from django.contrib.auth import get_user_model
from django.core.validators import MinValueValidator
from django.utils.translation import gettext_lazy as _
from django.utils import timezone
from math import ceil
from datetime import timedelta
from calendar import monthrange
import uuid
AMOUNT_MAX_DIGITS=10
AMOUNT_DECIMALS=2
# See https://docs.djangoproject.com/en/dev/ref/models/fields/#field-choices-enum-types
class RecurringPeriod(models.TextChoices):
ONE_TIME = 'ONCE', _('Onetime')
PER_YEAR = 'YEAR', _('Per Year')
PER_MONTH = 'MONTH', _('Per Month')
PER_MINUTE = 'MINUTE', _('Per Minute')
PER_DAY = 'DAY', _('Per Day')
PER_HOUR = 'HOUR', _('Per Hour')
PER_SECOND = 'SECOND', _('Per Second')
class Bill(models.Model):
uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
owner = models.ForeignKey(get_user_model(),
on_delete=models.CASCADE)
creation_date = models.DateTimeField(auto_now_add=True)
starting_date = models.DateTimeField()
ending_date = models.DateTimeField()
due_date = models.DateField()
valid = models.BooleanField(default=True)
@property
def records(self):
bill_records = []
orders = Order.objects.filter(bill=self)
for order in orders:
for order_record in order.records:
bill_record = BillRecord(self, order_record)
bill_records.append(bill_record)
return bill_records
@property
def total(self):
return reduce(lambda acc, record: acc + record.amount(), self.records, 0)
@property
def final(self):
# A bill is final when its ending date is passed.
return self.ending_date < timezone.now()
class BillRecord():
def __init__(self, bill, order_record):
self.bill = bill
self.order = order_record.order
self.setup_fee = order_record.setup_fee
self.recurring_price = order_record.recurring_price
self.recurring_period = order_record.recurring_period
self.description = order_record.description
def amount(self):
# Compute billing delta.
billed_until = self.bill.ending_date
if self.order.ending_date != None and self.order.ending_date < self.order.ending_date:
billed_until = self.order.ending_date
billed_from = self.bill.starting_date
if self.order.starting_date > self.bill.starting_date:
billed_from = self.order.starting_date
if billed_from > billed_until:
# TODO: think about and check edges cases. This should not be
# possible.
raise Exception('Impossible billing delta!')
billed_delta = billed_until - billed_from
# TODO: refactor this thing?
# TODO: weekly
# TODO: yearly
if self.recurring_period == RecurringPeriod.PER_MONTH:
days = ceil(billed_delta / timedelta(days=1))
# XXX: we assume monthly bills for now.
if (self.bill.starting_date.year != self.bill.starting_date.year or
self.bill.starting_date.month != self.bill.ending_date.month):
raise Exception('Bill {} covers more than one month. Cannot bill PER_MONTH.'.
format(self.bill.uuid))
# XXX: minumal length of monthly order is to be enforced somewhere else.
(_, days_in_month) = monthrange(
self.bill.starting_date.year,
self.bill.starting_date.month)
adjusted_recurring_price = self.recurring_price / days_in_month
recurring_price = adjusted_recurring_price * days
return self.recurring_price # TODO
elif self.recurring_period == RecurringPeriod.PER_DAY:
days = ceil(billed_delta / timedelta(days=1))
return self.recurring_price * days
elif self.recurring_period == RecurringPeriod.PER_HOUR:
hours = ceil(billed_delta / timedelta(hours=1))
return self.recurring_price * hours
elif self.recurring_period == RecurringPeriod.PER_SECOND:
seconds = ceil(billed_delta / timedelta(seconds=1))
return self.recurring_price * seconds
else:
raise Exception('Unsupported recurring period: {}.'.
format(record.recurring_period))
# /!\ BIG FAT WARNING /!\ #
#
# Order are assumed IMMUTABLE and used as SOURCE OF TRUST for generating
# bills. Do **NOT** mutate then!
#
# Why? We need to store the state somewhere since product are mutable (e.g.
# adding RAM to VM, changing price of 1GB of RAM, ...). An alternative could
# have been to only store the state in bills but would have been more
# confusing: the order is a 'contract' with the customer, were both parts
# agree on deal => That's what we want to keep archived.
#
# /!\ BIG FAT WARNING /!\ #
class Order(models.Model):
uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
owner = models.ForeignKey(get_user_model(),
on_delete=models.CASCADE,
editable=False)
# TODO: enforce ending_date - starting_date to be larger than recurring_period.
creation_date = models.DateTimeField(auto_now_add=True)
starting_date = models.DateTimeField(auto_now_add=True)
ending_date = models.DateTimeField(blank=True,
null=True)
bill = models.ManyToManyField(Bill,
editable=False,
blank=True)
recurring_period = models.CharField(max_length=32,
choices = RecurringPeriod.choices,
default = RecurringPeriod.PER_MONTH)
@property
def records(self):
return OrderRecord.objects.filter(order=self)
@property
def setup_fee(self):
return reduce(lambda acc, record: acc + record.setup_fee, self.records, 0)
@property
def recurring_price(self):
return reduce(lambda acc, record: acc + record.recurring_price, self.records, 0)
def add_record(self, setup_fee, recurring_price, description):
OrderRecord.objects.create(order=self,
setup_fee=setup_fee,
recurring_price=recurring_price,
description=description)
class OrderRecord(models.Model):
order = models.ForeignKey(Order, on_delete=models.CASCADE)
setup_fee = models.DecimalField(default=0.0,
max_digits=AMOUNT_MAX_DIGITS,
decimal_places=AMOUNT_DECIMALS,
validators=[MinValueValidator(0)])
recurring_price = models.DecimalField(default=0.0,
max_digits=AMOUNT_MAX_DIGITS,
decimal_places=AMOUNT_DECIMALS,
validators=[MinValueValidator(0)])
description = models.TextField()
@property
def recurring_period(self):
return self.order.recurring_period
@property
def starting_date(self):
return self.order.starting_date
@property
def ending_date(self):
return self.order.ending_date
class PaymentMethod(models.Model):
uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
owner = models.ForeignKey(get_user_model(),
on_delete=models.CASCADE,
editable=False)
source = models.CharField(max_length=256,
choices = (
('stripe', 'Stripe'),
('unknown', 'Unknown'),
),
default='stripe')
description = models.TextField()
primary = models.BooleanField(default=True)
# Only used for "Stripe" source
stripe_card_id = models.CharField(max_length=32, blank=True, null=True)
def charge(self, amount):
if amount > 0: # Make sure we don't charge negative amount by errors...
if self.source == 'stripe':
# TODO: wire to stripe, see meooow-payv1/strip_utils.py
payment = Payment(owner=self.owner, source=self.source, amount=amount)
payment.save() # TODO: Check return status
return True
else:
# We do not handle that source yet.
return False
else:
return False
class Meta:
unique_together = [['owner', 'primary']]
class Payment(models.Model):
uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
owner = models.ForeignKey(get_user_model(),
on_delete=models.CASCADE)
amount = models.DecimalField(
default=0.0,
max_digits=AMOUNT_MAX_DIGITS,
decimal_places=AMOUNT_DECIMALS,
validators=[MinValueValidator(0)])
source = models.CharField(max_length=256,
choices = (
('wire', 'Wire Transfer'),
('stripe', 'Stripe'),
('voucher', 'Voucher'),
('referral', 'Referral'),
('unknown', 'Unknown')
),
default='unknown')
timestamp = models.DateTimeField(editable=False, auto_now_add=True)
class Product(models.Model):
uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
owner = models.ForeignKey(get_user_model(),
on_delete=models.CASCADE,
editable=False)
description = ""
status = models.CharField(max_length=256,
choices = (
('pending', 'Pending'),
('being_created', 'Being created'),
('active', 'Active'),
('deleted', 'Deleted')
),
default='pending'
)
order = models.ForeignKey(Order,
on_delete=models.CASCADE,
editable=False,
null=True)
@property
def recurring_price(self, recurring_period=RecurringPeriod.PER_MONTH):
pass # To be implemented in child.
@property
def setup_fee(self):
return 0
class Meta:
abstract = True