Sendmail plugin: Allow filtering for check-ins (#1382)

* Allow filtering mass-emails for Checkin Lists

* Allow filtering mass emails for not checked in

* Fix email filtering logic issue

* Use Select2 for checkin lists selection

* sendmail plugin: Make checkin list filtering optional

* Remove unused constant

* Re-size panel to only fit the right column

* Revert incorrect JavaScript change

* Change semantics of not_checked_in

* Introduce a subquery to filter on position properties

src/pretix/plugins/sendmail/forms.py

@@ -1,12 +1,13 @@
 from django import forms
 from django.urls import reverse
 from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django_scopes.forms import SafeModelMultipleChoiceField
 from i18nfield.forms import I18nFormField, I18nTextarea, I18nTextInput
 
 from pretix.base.email import get_available_placeholders
 from pretix.base.forms import PlaceholderValidator
-from pretix.base.models import Item, Order, SubEvent
-from pretix.control.forms.widgets import Select2
+from pretix.base.models import CheckinList, Item, Order, SubEvent
+from pretix.control.forms.widgets import Select2, Select2Multiple
 
 
 class MailForm(forms.Form):
@@ -27,6 +28,12 @@ class MailForm(forms.Form):
         required=True,
         queryset=Item.objects.none()
     )
+    filter_checkins = forms.BooleanField(
+        label=_('Filter check-in status'),
+        required=False
+    )
+    checkin_lists = SafeModelMultipleChoiceField(queryset=CheckinList.objects.none(), required=False)  # overridden later
+    not_checked_in = forms.BooleanField(label=_("Send to customers not checked in"), required=False)
     subevent = forms.ModelChoiceField(
         SubEvent.objects.none(),
         label=_('Only send to customers of'),
@@ -96,6 +103,21 @@ class MailForm(forms.Form):
         if not self.initial.get('items'):
             self.initial['items'] = event.items.all()
 
+        self.fields['checkin_lists'].queryset = event.checkin_lists.all()
+        self.fields['checkin_lists'].widget = Select2Multiple(
+            attrs={
+                'data-model-select2': 'generic',
+                'data-select2-url': reverse('control:event.orders.checkinlists.select2', kwargs={
+                    'event': event.slug,
+                    'organizer': event.organizer.slug,
+                }),
+                'data-placeholder': _('Send to customers checked in on list'),
+                'data-inverse-dependency': '#id_not_checked_in'
+            }
+        )
+        self.fields['checkin_lists'].widget.choices = self.fields['checkin_lists'].choices
+        self.fields['checkin_lists'].label = _('Send to customers checked in on list')
+
         if event.has_subevents:
             self.fields['subevent'].queryset = event.subevents.all()
             self.fields['subevent'].widget = Select2(