Allow to revert a gift card refund

src/pretix/control/templates/pretixcontrol/organizers/giftcard.html

@@ -64,6 +64,14 @@
                                         <a href="{% url "control:event.order" event=t.order.event.slug organizer=t.order.event.organizer.slug code=t.order.code %}">
                                             {{ t.order.full_code }}
                                         </a>
+                                        {% if t.value > 0 and t.value <= card.value %}
+                                            <button type="submit" name="revert" value="{{ t.pk }}"
+                                                    class="btn btn-default btn-xs" data-toggle="tooltip"
+                                                    title="{% trans "Create a payment on the respective order that cancels out with this transaction. The order will then likely be overpaid." %}">
+                                                <span class="fa fa-repeat"></span>
+                                                {% trans "Revert" %}
+                                            </button>
+                                        {% endif %}
                                     {% else %}
                                         <em>{% trans "Manual transaction" %}{% if t.text %}: {{ t.text }}{% endif %}</em>
                                     {% endif %}

src/pretix/control/views/organizer.py

@@ -23,11 +23,12 @@ from django.views.generic import (
 from pretix.api.models import WebHook
 from pretix.base.auth import get_auth_backends
 from pretix.base.models import (
-    Device, GiftCard, Organizer, Team, TeamInvite, User,
+    Device, GiftCard, OrderPayment, Organizer, Team, TeamInvite, User,
 )
 from pretix.base.models.event import Event, EventMetaProperty, EventMetaValue
 from pretix.base.models.giftcards import gen_giftcard_secret
 from pretix.base.models.organizer import TeamAPIToken
+from pretix.base.payment import PaymentException
 from pretix.base.services.mail import SendMailException, mail
 from pretix.control.forms.filter import (
     EventFilterForm, GiftCardFilterForm, OrganizerFilterForm,
@@ -998,7 +999,36 @@ class GiftCardDetailView(OrganizerDetailViewMixin, OrganizerPermissionRequiredMi
     @transaction.atomic()
     def post(self, request, *args, **kwargs):
         self.object = GiftCard.objects.select_for_update().get(pk=self.get_object().pk)
-        if 'value' in request.POST:
+        if 'revert' in request.POST:
+            t = get_object_or_404(self.object.transactions.all(), pk=request.POST.get('revert'), order__isnull=False)
+            if self.object.value - t.value < Decimal('0.00'):
+                messages.error(request, _('Gift cards are not allowed to have negative values.'))
+            elif t.value > 0:
+                r = t.order.payments.create(
+                    order=t.order,
+                    state=OrderPayment.PAYMENT_STATE_CREATED,
+                    amount=t.value,
+                    provider='giftcard',
+                    info=json.dumps({
+                        'gift_card': self.object.pk,
+                        'retry': True,
+                    })
+                )
+                try:
+                    r.payment_provider.execute_payment(None, r)
+                except PaymentException as e:
+                    with transaction.atomic():
+                        r.state = OrderPayment.PAYMENT_STATE_FAILED
+                        r.save()
+                        t.order.log_action('pretix.event.order.payment.failed', {
+                            'local_id': r.local_id,
+                            'provider': r.provider,
+                            'error': str(e)
+                        })
+                    messages.error(request, _('The transaction could not be reversed.'))
+                else:
+                    messages.success(request, _('The transaction has been reversed.'))
+        elif 'value' in request.POST:
             try:
                 value = DecimalField(localize=True).to_python(request.POST.get('value'))
             except ValidationError:

src/tests/control/test_giftcards.py

@@ -1,6 +1,12 @@
-import pytest
+from datetime import timedelta
 
-from pretix.base.models import Organizer, Team, User
+import pytest
+from django.utils.timezone import now
+from django_scopes import scopes_disabled
+
+from pretix.base.models import (
+    Order, OrderPayment, OrderRefund, Organizer, Team, User,
+)
 
 
 @pytest.fixture
@@ -83,6 +89,37 @@ def test_card_detail_view_transact(organizer, admin_user, gift_card, client):
     assert gift_card.all_logentries().count() == 1
 
 
+@pytest.mark.django_db
+def test_card_detail_view_transact_revert_refund(organizer, admin_user, gift_card, client):
+    with scopes_disabled():
+        event = organizer.events.create(
+            name='Dummy', slug='dummy',
+            date_from=now(), plugins='pretix.plugins.banktransfer,pretix.plugins.stripe,tests.testdummy'
+        )
+        o = Order.objects.create(
+            code='FOO', event=event, email='dummy@dummy.test',
+            status=Order.STATUS_CANCELED,
+            datetime=now(), expires=now() + timedelta(days=10),
+            total=14, locale='en'
+        )
+        o.payments.create(
+            amount=o.total, provider='banktransfer', state=OrderPayment.PAYMENT_STATE_CONFIRMED
+        )
+        r = o.refunds.create(
+            amount=o.total, provider='giftcard', state=OrderRefund.REFUND_STATE_DONE
+        )
+        t = gift_card.transactions.create(value=14, order=o, refund=r)
+
+    client.login(email='dummy@dummy.dummy', password='dummy')
+    r = client.post('/control/organizer/dummy/giftcard/{}/'.format(gift_card.pk), {
+        'revert': str(t.pk)
+    })
+    assert 'alert-success' in r.rendered_content
+    assert gift_card.value == 42
+    o.refresh_from_db()
+    assert o.pending_sum == -14
+
+
 @pytest.mark.django_db
 def test_card_detail_view_transact_min_value(organizer, admin_user, gift_card, client):
     client.login(email='dummy@dummy.dummy', password='dummy')