def assert_round_down(amount, expected):
self.assertEqual(round_down_cent(Decimal(amount)),
Decimal(expected))
def assert_round_down(amount, expected):
self.assertEqual(
round_down_cent(Decimal(amount)),
Decimal(expected)
)
def cancel(self, guid, prorated_refund=False, refund_amount=None):
"""Cancel a subscription
:param guid: the guid of subscription to cancel
:param prorated_refund: Should we generate a prorated refund
transaction according to remaining time of subscription period?
:param refund_amount: if refund_amount is given, it will be used
to refund customer, you cannot set prorated_refund with
refund_amount
:return: if prorated_refund is True, and the subscription is
refundable, the refund transaction guid will be returned
"""
if prorated_refund and refund_amount is not None:
raise ValueError('You cannot set refund_amount when '
'prorated_refund is True')
tx_model = TransactionModel(self.session)
subscription = self.get(guid, raise_error=True)
if subscription.canceled:
raise SubscriptionCanceledError('Subscription {} is already '
'canceled'.format(guid))
now = tables.now_func()
subscription.canceled = True
subscription.canceled_at = now
tx_guid = None
# should we do refund
do_refund = False
# we want to do a prorated refund here, however, if there is no any
# issued transaction, then no need to do a refund, just skip
if (
(prorated_refund or refund_amount is not None) and
subscription.period
):
previous_transaction = (
self.session.query(tables.Transaction)
.filter_by(subscription_guid=subscription.guid)
.order_by(tables.Transaction.scheduled_at.desc())
.first()
)
# it is possible the previous transaction is failed or retrying,
# so that we should only refund finished transaction
if previous_transaction.status == TransactionModel.STATUS_DONE:
do_refund = True
if do_refund:
if prorated_refund:
previous_datetime = previous_transaction.scheduled_at
# the total time delta in the period
total_delta = (
subscription.next_transaction_at - previous_datetime
)
total_seconds = decimal.Decimal(total_delta.total_seconds())
# the passed time so far since last transaction
elapsed_delta = now - previous_datetime
elapsed_seconds = decimal.Decimal(elapsed_delta.total_seconds())
# TODO: what about calculate in different granularity here?
# such as day or hour granularity?
rate = 1 - (elapsed_seconds / total_seconds)
amount = previous_transaction.amount * rate
amount = round_down_cent(amount)
else:
amount = round_down_cent(decimal.Decimal(refund_amount))
if amount > previous_transaction.amount:
raise ValueError('refund_amount cannot be grather than '
'subscription amount {}'
.format(previous_transaction.amount))
# make sure we will not refund zero dollar
# TODO: or... should we?
if amount:
tx_guid = tx_model.create(
subscription_guid=subscription.guid,
amount=amount,
transaction_type=tx_model.TYPE_REFUND,
scheduled_at=subscription.next_transaction_at,
refund_to_guid=previous_transaction.guid,
)
# cancel not done transactions (exclude refund transaction)
Transaction = tables.Transaction
not_done_transactions = (
self.session.query(Transaction)
.filter_by(subscription_guid=guid)
.filter(Transaction.transaction_type != TransactionModel.TYPE_REFUND)
.filter(Transaction.status.in_([
tx_model.STATUS_INIT,
tx_model.STATUS_RETRYING,
]))
)
not_done_transactions.update(dict(
status=tx_model.STATUS_CANCELED,
updated_at=now,
), synchronize_session='fetch')
self.session.add(subscription)
self.session.flush()
return tx_guid
