Waiting list: Allow transfer to other subevent (#2811)

Co-authored-by: Richard Schreiber <schreiber@rami.io>
Co-authored-by: Raphael Michel <michel@rami.io>

src/pretix/control/forms/waitinglist.py

@@ -0,0 +1,56 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+from django.urls import reverse
+from django_scopes.forms import SafeModelChoiceField
+
+from pretix.base.forms import I18nModelForm
+from pretix.base.models import WaitingListEntry
+from pretix.control.forms.widgets import Select2
+
+
+class WaitingListEntryTransferForm(I18nModelForm):
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        if self.event.has_subevents:
+            self.fields['subevent'].required = True
+            self.fields['subevent'].queryset = self.event.subevents.all()
+            self.fields['subevent'].widget = Select2(
+                attrs={
+                    'data-model-select2': 'event',
+                    'data-select2-url': reverse('control:event.subevents.select2', kwargs={
+                        'event': self.event.slug,
+                        'organizer': self.event.organizer.slug,
+                    }),
+                }
+            )
+            self.fields['subevent'].widget.choices = self.fields['subevent'].choices
+
+    class Meta:
+        model = WaitingListEntry
+        fields = [
+            'subevent',
+        ]
+        field_classes = {
+            'subevent': SafeModelChoiceField,
+        }