Refs #105 -- Variation support for vouchers

src/pretix/control/forms/vouchers.py

@@ -1,18 +1,57 @@
+from django import forms
+from django.utils.translation import ugettext_lazy as _
+
 from pretix.base.forms import I18nModelForm
-from pretix.base.models import Voucher
+from pretix.base.models import Item, ItemVariation, Voucher
 
 
 class VoucherForm(I18nModelForm):
+    itemvar = forms.ChoiceField(
+        label=_("Product"),
+        help_text=_(
+            "This product is added to the user's cart if the voucher is redeemed."
+        )
+    )
+
     class Meta:
         model = Voucher
         localized_fields = '__all__'
         fields = [
-            'code', 'valid_until', 'block_quota', 'allow_ignore_quota', 'price', 'item'
+            'code', 'valid_until', 'block_quota', 'allow_ignore_quota', 'price'
         ]
 
     def __init__(self, *args, **kwargs):
+        instance = kwargs.get('instance')
+        initial = kwargs.get('initial')
+        if instance:
+            try:
+                if instance.variation:
+                    initial['itemvar'] = '%d-%d' % (instance.item.pk, instance.variation.pk)
+                elif instance.item:
+                    initial['itemvar'] = str(instance.item.pk)
+            except Item.DoesNotExist:
+                pass
         super().__init__(*args, **kwargs)
-        self.fields['item'].queryset = self.instance.event.items.all()
+        choices = []
+        for i in self.instance.event.items.prefetch_related('variations').all():
+            variations = list(i.variations.all())
+            if variations:
+                for v in variations:
+                    choices.append(('%d-%d' % (i.pk, v.pk), '%s – %s' % (i.name, v.value)))
+            else:
+                choices.append((str(i.pk), i.name))
+        self.fields['itemvar'].choices = choices
 
-    def _get_validation_exclusions(self):
-        return []
+    def save(self, commit=True):
+        if '-' in self.cleaned_data['itemvar']:
+            itemid, varid = self.cleaned_data['itemvar'].split('-')
+        else:
+            itemid, varid = self.cleaned_data['itemvar'], None
+        self.instance.item = Item.objects.get(pk=itemid, event=self.instance.event)
+        if varid:
+            self.instance.variation = ItemVariation.objects.get(pk=varid, item=self.instance.item)
+        else:
+            self.instance.variation = None
+        super().save(commit)
+
+        return ['item']