Allow to create refunds without a payment (#1914)

Co-authored-by: Martin Gross <gross@rami.io>

src/pretix/base/payment.py

@@ -9,7 +9,7 @@ import pytz
 from django import forms
 from django.conf import settings
 from django.contrib import messages
-from django.core.exceptions import ImproperlyConfigured
+from django.core.exceptions import ImproperlyConfigured, ValidationError
 from django.db import transaction
 from django.dispatch import receiver
 from django.forms import Form
@@ -773,6 +773,32 @@ class BasePaymentProvider:
         """
         raise PaymentException(_('Automatic refunds are not supported by this payment provider.'))
 
+    def new_refund_control_form_render(self, request: HttpRequest, order: Order) -> str:
+        """
+        Render a form that will be shown to backend users when trying to create a new refund.
+
+        Usually, refunds are created from an existing payment object, e.g. if there is a credit card
+        payment and the credit card provider returns ``True`` from ``payment_refund_supported``, the system
+        will automatically create an ``OrderRefund`` and call ``execute_refund`` on that payment. This method
+        can and should not be used in that situation! Instead, by implementing this method you can add a refund
+        flow for this payment provider that starts without an existing payment. For example, even though an order
+        was paid by credit card, it could easily be refunded by SEPA bank transfer. In that case, the SEPA bank
+        transfer provider would implement this method and return a form that asks for the IBAN.
+
+        This method should return HTML or ``None``. All form fields should have a globally unique name.
+        """
+        return
+
+    def new_refund_control_form_process(self, request: HttpRequest, amount: Decimal, order: Order) -> OrderRefund:
+        """
+        Process a backend user's request to initiate a new refund with an amount of ``amount`` for ``order``.
+
+        This method should parse the input provided to the form created and either raise ``ValidationError``
+        or return an ``OrderRefund`` object in ``created`` state that has not yet been saved to the database.
+        The system will then call ``execute_refund`` on that object.
+        """
+        raise ValidationError('Not implemented')
+
     def shred_payment_info(self, obj: Union[OrderPayment, OrderRefund]):
         """
         When personal data is removed from an event, this method is called to scrub payment-related data

src/pretix/control/templates/pretixcontrol/order/refund_choose.html

@@ -68,6 +68,28 @@
                             </td>
                         </tr>
                     {% endfor %}
+                    {% for prov, form in new_refunds %}
+                        <tr>
+                            <td></td>
+                            <td></td>
+                            <td>
+                                {{ prov.verbose_name }}
+                            </td>
+                            <td></td>
+                            <td>
+                                {% trans "Automatically refund" context "amount_label" %}
+                                <div class="input-group">
+                                    <input type="text" name="newrefund-{{ prov }}"
+                                           placeholder="{{ 0|floatformat:2 }}"
+                                           title="" class="form-control">
+                                    <span class="input-group-addon">
+                                        {{ request.event.currency }}
+                                    </span>
+                                </div><br>
+                                {{ form|safe }}
+                            </td>
+                        </tr>
+                    {% endfor %}
                     <tr>
                         <td></td>
                         <td></td>

src/pretix/control/views/item.py

@@ -46,8 +46,8 @@ from pretix.control.permissions import (
 from pretix.control.signals import item_forms, item_formsets
 from pretix.helpers.models import modelcopy
 
-from . import ChartContainingView, CreateView, PaginationMixin, UpdateView
 from ...base.channels import get_all_sales_channels
+from . import ChartContainingView, CreateView, PaginationMixin, UpdateView
 
 
 class ItemList(ListView):

src/pretix/control/views/orders.py

@@ -10,6 +10,7 @@ from urllib.parse import quote, urlencode
 import vat_moss.id
 from django.conf import settings
 from django.contrib import messages
+from django.core.exceptions import ValidationError
 from django.core.files import File
 from django.db import transaction
 from django.db.models import (
@@ -866,6 +867,29 @@ class OrderRefundView(OrderView):
                             })
                         ))
 
+            for identifier, prov in self.request.event.get_payment_providers().items():
+                prof_value = self.request.POST.get(f'newrefund-{identifier}', '0') or '0'
+                prof_value = formats.sanitize_separators(prof_value)
+                try:
+                    prof_value = Decimal(prof_value)
+                except (DecimalException, TypeError):
+                    messages.error(self.request, _('You entered an invalid number.'))
+                    is_valid = False
+                    continue
+                if prof_value > Decimal('0.00'):
+                    try:
+                        refund = prov.new_refund_control_form_process(self.request, prof_value, self.order)
+                    except ValidationError as e:
+                        for err in e:
+                            messages.error(self.request, err)
+                        is_valid = False
+                        continue
+                    if refund:
+                        refund_selected += refund.amount
+                        refund.comment = comment
+                        refund.source = OrderRefund.REFUND_SOURCE_ADMIN
+                        refunds.append(refund)
+
             for p in payments:
                 value = self.request.POST.get('refund-{}'.format(p.pk), '0') or '0'
                 value = formats.sanitize_separators(value)
@@ -907,7 +931,7 @@ class OrderRefundView(OrderView):
                         'local_id': r.local_id,
                         'provider': r.provider,
                     }, user=self.request.user)
-                    if r.payment or r.provider == "offsetting" or r.provider == "giftcard":
+                    if r.provider != "manual":
                         try:
                             r.payment_provider.execute_refund(r)
                         except PaymentException as e:
@@ -969,8 +993,17 @@ class OrderRefundView(OrderView):
                 messages.error(self.request, _('The refunds you selected do not match the selected total refund '
                                                'amount.'))
 
+        new_refunds = []
+        for identifier, prov in self.request.event.get_payment_providers().items():
+            form = prov.new_refund_control_form_render(self.request, self.order)
+            if form:
+                new_refunds.append(
+                    (prov, form)
+                )
+
         return render(self.request, 'pretixcontrol/order/refund_choose.html', {
             'payments': payments,
+            'new_refunds': new_refunds,
             'remainder': to_refund,
             'order': self.order,
             'comment': comment,
@@ -2078,7 +2111,7 @@ class ExportDoView(EventPermissionRequiredMixin, ExportMixin, AsyncAction, View)
             messages.error(
                 self.request,
                 str(_('There was a problem processing your input:')) + ' ' + ', '.join(
-                    ', '.join(l) for l in self.exporter.form.errors.values()
+                    ', '.join(line) for line in self.exporter.form.errors.values()
                 )
             )
             return redirect(reverse('control:event.orders.export', kwargs={

src/pretix/plugins/banktransfer/payment.py

@@ -1,6 +1,7 @@
 import json
 import textwrap
 from collections import OrderedDict
+from decimal import Decimal
 
 from django import forms
 from django.core.exceptions import ValidationError
@@ -13,7 +14,7 @@ from i18nfield.strings import LazyI18nString
 from localflavor.generic.forms import BICFormField, IBANFormField
 from localflavor.generic.validators import IBANValidator
 
-from pretix.base.models import OrderPayment, OrderRefund
+from pretix.base.models import Order, OrderPayment, OrderRefund
 from pretix.base.payment import BasePaymentProvider
 
 
@@ -298,6 +299,9 @@ class BankTransfer(BasePaymentProvider):
         We just keep a created refund object. It will be marked as done using the control view
         for bank transfer refunds.
         """
+        if refund.info_data.get('iban'):
+            return  # we're already done here
+
         if refund.payment is None:
             raise ValueError(_("Can only create a bank transfer refund from an existing payment."))
 
@@ -310,3 +314,59 @@ class BankTransfer(BasePaymentProvider):
 
     def refund_control_render(self, request: HttpRequest, refund: OrderRefund) -> str:
         return self._render_control_info(request, refund.order, refund.info_data)
+
+    class NewRefundForm(forms.Form):
+        payer = forms.CharField(
+            label=_('Account holder'),
+        )
+        iban = IBANFormField(
+            label=_('IBAN'),
+        )
+
+        def __init__(self, *args, **kwargs):
+            super().__init__(*args, **kwargs)
+            for n, f in self.fields.items():
+                f.required = False
+                f.widget.is_required = False
+
+        def clean_payer(self):
+            val = self.cleaned_data.get('payer')
+            if not val:
+                raise ValidationError(_("This field is required."))
+            return val
+
+        def clean_iban(self):
+            val = self.cleaned_data.get('iban')
+            if not val:
+                raise ValidationError(_("This field is required."))
+            return val
+
+    def new_refund_control_form_render(self, request: HttpRequest, order: Order) -> str:
+        f = self.NewRefundForm(
+            prefix="refund-banktransfer",
+            data=request.POST if request.method == "POST" and request.POST.get("refund-banktransfer-iban") else None,
+        )
+        template = get_template('pretixplugins/banktransfer/new_refund_control_form.html')
+        ctx = {
+            'form': f,
+        }
+        return template.render(ctx)
+
+    def new_refund_control_form_process(self, request: HttpRequest, amount: Decimal, order: Order) -> OrderRefund:
+        f = self.NewRefundForm(
+            prefix="refund-banktransfer",
+            data=request.POST
+        )
+        if not f.is_valid():
+            raise ValidationError(_('Your input was invalid, please see below for details.'))
+        return OrderRefund(
+            order=order,
+            payment=None,
+            state=OrderRefund.REFUND_STATE_CREATED,
+            amount=amount,
+            provider=self.identifier,
+            info=json.dumps({
+                'payer': f.cleaned_data['payer'],
+                'iban': self.norm(f.cleaned_data['iban']),
+            })
+        )

src/pretix/plugins/banktransfer/templates/pretixplugins/banktransfer/new_refund_control_form.html

@@ -0,0 +1,8 @@
+{% load i18n %}
+{% load ibanformat %}
+{% load bootstrap3 %}
+
+{% trans "to" %}
+{% bootstrap_field form.payer layout="inline" %}
+{% bootstrap_field form.iban layout="inline" %}
+{% bootstrap_form_errors form error_types="all" %}