Proof of concept

src/pretix/presale/checkoutflow.py

@@ -15,7 +15,7 @@ from django.utils.translation import (
 from django.views.generic.base import TemplateResponseMixin
 from django_scopes import scopes_disabled
 
-from pretix.base.models import Order
+from pretix.base.models import GiftCard, Order
 from pretix.base.models.orders import InvoiceAddress, OrderPayment
 from pretix.base.services.cart import (
     get_fees, set_cart_addons, update_tax_rates,
@@ -530,6 +530,24 @@ class PaymentStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
 
     def post(self, request):
         self.request = request
+        if request.POST.get("giftcard"):
+            # TODO: cross-organizer acceptance, check for valid money, …
+            try:
+                gc = GiftCard.objects.get(
+                    issuer=request.organizer,
+                    secret=request.POST.get("giftcard")
+                )
+                if gc.currency != request.event.currency:
+                    messages.error(self.request, _("This gift card does not support this currency."))
+                    return self.render()
+                if 'gift_cards' not in self.cart_session:
+                    self.cart_session['gift_cards'] = []
+                self.cart_session['gift_cards'] = self.cart_session['gift_cards'] + [gc.pk]
+                return self.render()
+            except GiftCard.DoesNotExist:
+                messages.error(self.request, _("This gift card is not known."))
+                return self.render()
+
         for p in self.provider_forms:
             if p['provider'].identifier == request.POST.get('payment', ''):
                 self.cart_session['payment'] = p['provider'].identifier
@@ -709,7 +727,7 @@ class ConfirmStep(CartMixin, AsyncAction, TemplateFlowStep):
         return self.do(self.request.event.id, self.payment_provider.identifier if self.payment_provider else None,
                        [p.id for p in self.positions], self.cart_session.get('email'),
                        translation.get_language(), self.invoice_address.pk, meta_info,
-                       request.sales_channel)
+                       request.sales_channel, self.cart_session.get('gift_cards'))
 
     def get_success_message(self, value):
         create_empty_cart_id(self.request)

src/pretix/presale/templates/pretixpresale/event/checkout_payment.html

@@ -11,6 +11,8 @@
     <form method="post">
         {% csrf_token %}
         <div class="panel-group" id="payment_accordion">
+            {# TODO: make this proper #}
+            <input type="text" class="form-control" placeholder="Add gift card" name="giftcard">
             {% for p in providers %}
                 <div class="panel panel-default" data-total="{{ p.total|floatformat:2 }}">
                     <label class="accordion-radio">