Quota form: Change item selection field per context (#3839)

* Change item checkbox select to multiselect widget

* Make item selection widget dependent on count

* Make item selection widget dependent on variable

* Adjust widget choices

* Fix widget choices

* Fix item variation key errors

* Simplify code

* Fix classname

* Improve argument name

* Fix widget name

src/pretix/control/forms/item.py

@@ -67,7 +67,7 @@ from pretix.control.forms import (
     ButtonGroupRadioSelect, ItemMultipleChoiceField, SizeValidationMixin,
     SplitDateTimeField, SplitDateTimePickerWidget,
 )
-from pretix.control.forms.widgets import Select2
+from pretix.control.forms.widgets import Select2, Select2ItemVarMulti
 from pretix.helpers.models import modelcopy
 from pretix.helpers.money import change_decimal_field
 
@@ -207,14 +207,20 @@ class QuestionOptionForm(I18nModelForm):
 
 
 class QuotaForm(I18nModelForm):
+    itemvars = forms.MultipleChoiceField(
+        label=_("Products"),
+        required=True,
+    )
+
     def __init__(self, **kwargs):
         self.instance = kwargs.get('instance', None)
         self.event = kwargs.get('event')
         items = kwargs.pop('items', None) or self.event.items.prefetch_related('variations')
+        searchable_selection = kwargs.pop('searchable_selection', None)
         self.original_instance = modelcopy(self.instance) if self.instance else None
         initial = kwargs.get('initial', {})
         if self.instance and self.instance.pk and 'itemvars' not in initial:
-            initial['itemvars'] = [str(i.pk) for i in self.instance.items.all()] + [
+            initial['itemvars'] = [str(i.pk) for i in self.instance.items.all() if (len(i.variations.all()) == 0)] + [
                 '{}-{}'.format(v.item_id, v.pk) for v in self.instance.variations.all()
             ]
         kwargs['initial'] = initial
@@ -231,12 +237,22 @@ class QuotaForm(I18nModelForm):
             else:
                 choices.append(('{}'.format(item.pk), str(item) if item.active else mark_safe(f'<strike class="text-muted">{escape(item)}</strike>')))
 
-        self.fields['itemvars'] = forms.MultipleChoiceField(
-            label=_('Products'),
-            required=True,
-            choices=choices,
-            widget=forms.CheckboxSelectMultiple
-        )
+        if searchable_selection:
+            self.fields['itemvars'].widget = Select2ItemVarMulti(
+                attrs={
+                    'data-model-select2': 'generic',
+                    'data-select2-url': reverse('control:event.items.itemvars.select2', kwargs={
+                        'event': self.event.slug,
+                        'organizer': self.event.organizer.slug,
+                    }),
+                    'data-placeholder': _('All products')
+                },
+                choices=choices,
+            )
+        else:
+            self.fields['itemvars'].widget = forms.CheckboxSelectMultiple()
+
+        self.fields['itemvars'].choices = choices
 
         if self.event.has_subevents:
             self.fields['subevent'].queryset = self.event.subevents.all()

src/pretix/control/forms/subevents.py

@@ -360,6 +360,7 @@ class BulkSubEventItemVariationForm(SubEventItemVariationForm):
 class QuotaFormSet(I18nInlineFormSet):
 
     def __init__(self, *args, **kwargs):
+        self.searchable_selection = kwargs.pop('searchable_selection', None)
         self.event = kwargs.pop('event', None)
         self.locales = self.event.settings.get('locales')
         super().__init__(*args, **kwargs)
@@ -372,7 +373,7 @@ class QuotaFormSet(I18nInlineFormSet):
         kwargs['locales'] = self.locales
         kwargs['event'] = self.event
         kwargs['items'] = self.items
-        kwargs['items'] = self.items
+        kwargs['searchable_selection'] = self.searchable_selection
         return super()._construct_form(i, **kwargs)
 
     @property

src/pretix/control/forms/widgets.py

@@ -77,3 +77,19 @@ class Select2ItemVarQuotaMixin(Select2Mixin):
 
 class Select2ItemVarQuota(Select2ItemVarQuotaMixin, forms.Select):
     pass
+
+
+class Select2ItemVarMulti(Select2Mixin, forms.SelectMultiple):
+    def options(self, name, value, attrs=None):
+        # we need this for multi-selection without a queryset for the selection of items and variations
+        for i, v in enumerate(value):
+            yield self.create_option(
+                None,
+                v,
+                dict(self.choices)[v],
+                True,
+                i,
+                subindex=None,
+                attrs=attrs
+            )
+        return