Fixed #86 -- Decide about variations at product creation

src/pretix/base/models/items.py

@@ -211,6 +211,10 @@ class Item(LoggedModel):
         return min([q.availability() for q in self.quotas.all()],
                    key=lambda s: (s[0], s[1] if s[1] is not None else sys.maxsize))
 
+    @cached_property
+    def has_variations(self):
+        return self.variations.exists()
+
 
 class ItemVariation(models.Model):
     """

src/pretix/control/forms/item.py

@@ -2,7 +2,7 @@ import copy
 
 from django import forms
 from django.forms import BooleanField, ModelMultipleChoiceField
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import ugettext as __, ugettext_lazy as _
 
 from pretix.base.forms import I18nModelForm
 from pretix.base.models import (
@@ -101,6 +101,20 @@ class ItemFormGeneral(I18nModelForm):
         ]
 
 
+class ItemCreateForm(ItemFormGeneral):
+    has_variations = forms.BooleanField(label=_('The product should exist in multiple variations'),
+                                        help_text=_('Select this option e.g. for t-shirts that come in multiple sizes. '
+                                                    'You can select the variations in the next step.'))
+
+    def save(self, *args, **kwargs):
+        instance = super().save(*args, **kwargs)
+        if self.cleaned_data.get('has_variations'):
+            ItemVariation.objects.create(
+                item=instance, value=__('Standard')
+            )
+        return instance
+
+
 class ItemVariationForm(I18nModelForm):
     class Meta:
         model = ItemVariation

src/pretix/control/templates/pretixcontrol/item/base.html

@@ -4,10 +4,20 @@
 {% block content %}
     {% if object.id %}
         <h1>{% trans "Modify product:" %} {{ object.name }}</h1>
+        {% if object.has_variations %}
         <ul class="nav nav-pills">
-            <li {% if "event.item" == url_name %}class="active"{% endif %}><a href="{% url 'control:event.item' organizer=request.event.organizer.slug event=request.event.slug item=object.id %}">{% trans "General information" %}</a></li>
+            <li {% if "event.item" == url_name %}class="active"{% endif %}>
-            <li {% if "event.item.variations" == url_name %}class="active"{% endif %}><a href="{% url 'control:event.item.variations' organizer=request.event.organizer.slug event=request.event.slug item=object.id %}">{% trans "Variations" %}</a></li>
+                <a href="{% url 'control:event.item' organizer=request.event.organizer.slug event=request.event.slug item=object.id %}">
+                    {% trans "General information" %}
+                </a>
+            </li>
+            <li {% if "event.item.variations" == url_name %}class="active"{% endif %}>
+                <a href="{% url 'control:event.item.variations' organizer=request.event.organizer.slug event=request.event.slug item=object.id %}">
+                    {% trans "Variations" %}
+                </a>
+            </li>
         </ul>
+        {% endif %}
     {% else %}
         <h1>{% trans "Create product" %}</h1>
         <p>{% blocktrans trimmed %}

src/pretix/control/templates/pretixcontrol/item/index.html

@@ -8,6 +8,9 @@
 			<legend>{% trans "General information" %}</legend>
 			{% bootstrap_field form.name layout="horizontal" %}
 			{% bootstrap_field form.active layout="horizontal" %}
+            {% if form.has_variations %}
+                {% bootstrap_field form.has_variations layout="horizontal" %}
+            {% endif %}
 			{% bootstrap_field form.category layout="horizontal" %}
             {% bootstrap_field form.admission layout="horizontal" %}
 			{% bootstrap_field form.description layout="horizontal" %}

src/pretix/control/views/item.py

@@ -17,7 +17,8 @@ from pretix.base.models import (
     Item, ItemCategory, ItemVariation, Question, Quota,
 )
 from pretix.control.forms.item import (
-    CategoryForm, ItemFormGeneral, ItemVariationForm, QuestionForm, QuotaForm,
+    CategoryForm, ItemCreateForm, ItemFormGeneral, ItemVariationForm,
+    QuestionForm, QuotaForm,
 )
 from pretix.control.permissions import (
     EventPermissionRequiredMixin, event_permission_required,
@@ -491,7 +492,7 @@ class ItemDetailMixin(SingleObjectMixin):
 
 
 class ItemCreate(EventPermissionRequiredMixin, CreateView):
-    form_class = ItemFormGeneral
+    form_class = ItemCreateForm
     template_name = 'pretixcontrol/item/index.html'
     permission = 'can_change_items'