Fix #202 -- Allow the manual ordering of questions

* Allow the manual ordering of questions
Update Unit Tests
Fix some typos

* Add migrations

* Minor notation change

src/pretix/base/migrations/0032_question_position.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.9 on 2016-08-21 19:27
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0031_auto_20160816_0648'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='question',
+            name='position',
+            field=models.IntegerField(default=0),
+        ),
+    ]

src/pretix/base/migrations/0033_auto_20160821_2222.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.9.9 on 2016-08-21 22:22
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0032_question_position'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='question',
+            options={'ordering': ('position', 'id'), 'verbose_name': 'Question', 'verbose_name_plural': 'Questions'},
+        ),
+    ]

src/pretix/base/models/items.py

@@ -386,10 +386,14 @@ class Question(LoggedModel):
         blank=True,
         help_text=_('This question will be asked to buyers of the selected products')
     )
+    position = models.IntegerField(
+        default=0
+    )
 
     class Meta:
         verbose_name = _("Question")
         verbose_name_plural = _("Questions")
+        ordering = ('position', 'id')
 
     def __str__(self):
         return str(self.question)
@@ -404,6 +408,13 @@ class Question(LoggedModel):
         if self.event:
             self.event.get_cache().clear()
 
+    @property
+    def sortkey(self):
+        return self.position, self.id
+
+    def __lt__(self, other) -> bool:
+        return self.sortkey < other.sortkey
+
 
 class QuestionOption(models.Model):
     question = models.ForeignKey('Question', related_name='options')

src/pretix/control/templates/pretixcontrol/items/questions.html

@@ -41,6 +41,10 @@
                     {% url "control:event.items.questions.edit" organizer=request.event.organizer.slug event=request.event.slug question=q.id %}">{{ q.question }}</a></strong>
                         </td>
                         <td>{{ q.get_type_display }}</td>
+                        <td>
+                            <a href="{% url "control:event.items.questions.up" organizer=request.event.organizer.slug event=request.event.slug question=q.id %}" class="btn btn-default btn-sm {% if forloop.counter0 == 0 %}disabled{% endif %}"><i class="fa fa-arrow-up"></i></a>
+                            <a href="{% url "control:event.items.questions.down" organizer=request.event.organizer.slug event=request.event.slug question=q.id %}" class="btn btn-default btn-sm {% if forloop.revcounter0 == 0 %}disabled{% endif %}"><i class="fa fa-arrow-down"></i></a>
+                        </td>
                         <td class="text-right"><a href="
                     {% url "control:event.items.questions.delete" organizer=request.event.organizer.slug event=request.event.slug question=q.id %}" class="btn btn-danger btn-sm"><i class="fa fa-trash"></i></a>
                         </td>

src/pretix/control/urls.py

@@ -50,6 +50,9 @@ urlpatterns = [
         url(r'^questions/$', item.QuestionList.as_view(), name='event.items.questions'),
         url(r'^questions/(?P<question>\d+)/delete$', item.QuestionDelete.as_view(),
             name='event.items.questions.delete'),
+        url(r'^questions/(?P<question>\d+)/up$', item.question_move_up, name='event.items.questions.up'),
+        url(r'^questions/(?P<question>\d+)/down$', item.question_move_down,
+            name='event.items.questions.down'),
         url(r'^questions/(?P<question>\d+)/$', item.QuestionUpdate.as_view(),
             name='event.items.questions.edit'),
         url(r'^questions/add$', item.QuestionCreate.as_view(), name='event.items.questions.add'),

src/pretix/control/views/item.py

@@ -208,7 +208,7 @@ def category_move(request, category, up=True):
         if cat.position != i:
             cat.position = i
             cat.save()
-    messages.success(request, _('The order of categories as been updated.'))
+    messages.success(request, _('The order of categories has been updated.'))
 
 
 @event_permission_required("can_change_items")
@@ -237,6 +237,49 @@ class QuestionList(ListView):
         return self.request.event.questions.all()
 
 
+def question_move(request, question, up=True):
+    """
+    This is a helper function to avoid duplicating code in question_move_up and
+    question_move_down. It takes a question and a direction and then tries to bring
+    all items for this question in a new order.
+    """
+    try:
+        question = request.event.questions.get(
+            id=question
+        )
+    except Question.DoesNotExist:
+        raise Http404(_("The selected question does not exist."))
+    questions = list(request.event.questions.order_by("position"))
+
+    index = questions.index(question)
+    if index != 0 and up:
+        questions[index - 1], questions[index] = questions[index], questions[index - 1]
+    elif index != len(questions) - 1 and not up:
+        questions[index + 1], questions[index] = questions[index], questions[index + 1]
+
+    for i, qt in enumerate(questions):
+        if qt.position != i:
+            qt.position = i
+            qt.save()
+    messages.success(request, _('The order of questions has been updated.'))
+
+
+@event_permission_required("can_change_items")
+def question_move_up(request, organizer, event, question):
+    question_move(request, question, up=True)
+    return redirect('control:event.items.questions',
+                    organizer=request.event.organizer.slug,
+                    event=request.event.slug)
+
+
+@event_permission_required("can_change_items")
+def question_move_down(request, organizer, event, question):
+    question_move(request, question, up=False)
+    return redirect('control:event.items.questions',
+                    organizer=request.event.organizer.slug,
+                    event=request.event.slug)
+
+
 class QuestionDelete(EventPermissionRequiredMixin, DeleteView):
     model = Question
     template_name = 'pretixcontrol/items/question_delete.html'

src/pretix/presale/views/questions.py

@@ -9,7 +9,7 @@ class QuestionsViewMixin:
     @cached_property
     def forms(self):
         """
-        A list of forms with one form for each cart cart position that has questions
+        A list of forms with one form for each cart position that has questions
         the user can answer. All forms have a custom prefix, so that they can all be
         submitted at once.
         """