Fix #303 -- valid until date for payment providers (#334)

* Fix 303

* fix #303

* minor refactoring

* improving timezone aware

* added documentation

src/pretix/base/payment.py

@@ -1,13 +1,16 @@
 from collections import OrderedDict
+from datetime import date
 from decimal import Decimal
 from typing import Any, Dict
 
+import pytz
 from django import forms
 from django.contrib import messages
 from django.dispatch import receiver
 from django.forms import Form
 from django.http import HttpRequest
 from django.template.loader import get_template
+from django.utils.timezone import now
 from django.utils.translation import ugettext_lazy as _
 
 from pretix.base.decimal import round_decimal
@@ -86,7 +89,7 @@ class BasePaymentProvider:
         settings keys and the values should be corresponding Django form fields.
 
         The default implementation returns the appropriate fields for the ``_enabled``,
-        ``_fee_abs`` and ``_fee_percent`` settings mentioned above.
+        ``_fee_abs``, ``_fee_percent`` and ``_availability_date`` settings mentioned above.
 
         We suggest that you return an ``OrderedDict`` object instead of a dictionary
         and make use of the default implementation. Your implementation could look
@@ -126,6 +129,13 @@ class BasePaymentProvider:
                  help_text=_('Percentage'),
                  required=False
              )),
+            ('_availability_date',
+             forms.DateField(
+                 label=_('Available until'),
+                 help_text=_('Users will not be able to choose this payment provider after the given date.'),
+                 required=False,
+                 widget=forms.DateInput(attrs={'class': 'datepickerfield'})
+             )),
             ('_fee_reverse_calc',
              forms.BooleanField(
                  label=_('Calculate the fee from the total value including the fee.'),
@@ -190,6 +200,14 @@ class BasePaymentProvider:
         form.fields = self.payment_form_fields
         return form
 
+    def _is_still_available(self, now_dt=None):
+        now_dt = now_dt or now()
+        tz = pytz.timezone(self.event.settings.timezone)
+        availability_date = self.settings.get('_availability_date', as_type=date)
+        if availability_date:
+            return availability_date >= now_dt.astimezone(tz).date()
+        return True
+
     def is_allowed(self, request: HttpRequest) -> bool:
         """
         You can use this method to disable this payment provider for certain groups
@@ -197,9 +215,9 @@ class BasePaymentProvider:
         user will not be able to select this payment method. This will only be called
         during checkout, not on retrying.
 
-        The default implementation always returns ``True``.
+        The default implementation checks for the _availability_date setting to be either unset or in the future.
         """
-        return True
+        return self._is_still_available()
 
     def payment_form_render(self, request: HttpRequest) -> str:
         """
@@ -335,11 +353,11 @@ class BasePaymentProvider:
         Will be called to check whether it is allowed to change the payment method of
         an order to this one.
 
-        The default implementation always returns ``True``.
+        The default implementation checks for the _availability_date setting to be either unset or in the future.
 
         :param order: The order object
         """
-        return True
+        return self._is_still_available()
 
     def order_can_retry(self, order: Order) -> bool:
         """

src/tests/base/test_payment.py

@@ -1,6 +1,8 @@
+import datetime
 from decimal import Decimal
 
 import pytest
+import pytz
 from django.utils.timezone import now
 from tests.testdummy.payment import DummyPaymentProvider
 
@@ -50,3 +52,32 @@ def test_payment_fee_reverse_percent_and_abs_default(event):
     prov.settings.set('_fee_abs', Decimal('0.30'))
     prov.settings.set('_fee_percent', Decimal('2.90'))
     assert prov.calculate_fee(Decimal('100.00')) == Decimal('3.30')
+
+
+@pytest.mark.django_db
+def test_availability_date_available(event):
+    prov = DummyPaymentProvider(event)
+    prov.settings.set('_availability_date', datetime.date.today() + datetime.timedelta(days=1))
+    result = prov._is_still_available()
+    assert result
+
+
+@pytest.mark.django_db
+def test_availability_date_not_available(event):
+    prov = DummyPaymentProvider(event)
+    prov.settings.set('_availability_date', datetime.date.today() - datetime.timedelta(days=1))
+    result = prov._is_still_available()
+    assert not result
+
+
+@pytest.mark.django_db
+def test_availability_date_timezones(event):
+    event.settings.set('timezone', 'US/Pacific')
+    prov = DummyPaymentProvider(event)
+    prov.settings.set('_availability_date', '2016-12-01')
+
+    tz = pytz.timezone('US/Pacific')
+    utc = pytz.timezone('UTC')
+    assert prov._is_still_available(tz.localize(datetime.datetime(2016, 11, 30, 23, 0, 0)).astimezone(utc))
+    assert prov._is_still_available(tz.localize(datetime.datetime(2016, 12, 1, 23, 59, 0)).astimezone(utc))
+    assert not prov._is_still_available(tz.localize(datetime.datetime(2016, 12, 2, 0, 0, 1)).astimezone(utc))