Add sub-events and relative date settings (#503)

* Data model

* little crud

* SubEventItemForm etc

* Drop SubEventItem.active, quota editor

* Fix failing tests

* First frontend stuff

* Addons form stuff

* Quota calculation

* net price display on EventIndex

* Add tests, solve some bugs

* Correct quota selection in more places, consolidate pricing logic

* Fix failing quota tests

* Fix TypeError

* Add tests for checkout

* Fixed a bug in QuotaForm

* Prevent immutable cart if a quota was removed from an item

* Add tests for pricing

* Handle waiting list

* Filter in check-in list

* Fixed import lost in rebase

* Fix waiting list widget

* Voucher management

* Voucher redemption

* Fix broken tests

* Add subevents to OrderChangeManager

* Create a subevent during event creation

* Fix bulk voucher creation

* Introduce subevent.active

* Copy from for subevents

* Show active in list

* ICal download for subevents

* Check start and end of presale

* Failing tests / show cart logic

* Test

* Rebase migrations

* REST API integration of sub-events

* Integrate quota calculation into the traditional quota form

* Make subevent argument to add_position optional

* Log-display foo

* pretixdroid and subevents

* Filter by subevent

* Add more tests

* Some mor tests

* Rebase fixes

* More tests

* Relative dates

* Restrict selection in relative datetime widgets

* Filter subevent list

* Re-label has_subevents

* Rebase fixes, subevents in calendar view

* Performance and caching issues

* Refactor calendar templates

* Permission tests

* Calendar fixes and month selection

* subevent selection

* Rename subevents to dates

* Add tests for calendar views

src/pretix/control/forms/orders.py

@@ -4,10 +4,12 @@ from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.formats import localize
 from django.utils.timezone import now
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import pgettext_lazy, ugettext_lazy as _
 
 from pretix.base.forms import I18nModelForm
 from pretix.base.models import Item, ItemAddOn, Order, OrderPosition
+from pretix.base.models.event import SubEvent
+from pretix.base.services.pricing import get_price
 
 
 class ExtendForm(I18nModelForm):
@@ -55,6 +57,15 @@ class CommentForm(I18nModelForm):
         }
 
 
+class SubEventChoiceField(forms.ModelChoiceField):
+    def label_from_instance(self, obj):
+        p = get_price(self.instance.item, self.instance.variation,
+                      voucher=self.instance.voucher,
+                      subevent=obj)
+        return '{} – {} ({} {})'.format(obj.name, obj.get_date_range_display(),
+                                        p, self.instance.order.event.currency)
+
+
 class OrderPositionAddForm(forms.Form):
     do = forms.BooleanField(
         label=_('Add a new product to the order'),
@@ -74,6 +85,12 @@ class OrderPositionAddForm(forms.Form):
         label=_('Gross price'),
         help_text=_("Keep empty for the product's default price")
     )
+    subevent = forms.ModelChoiceField(
+        SubEvent.objects.none(),
+        label=pgettext_lazy('subevent', 'Date'),
+        required=True,
+        empty_label=None
+    )
 
     def __init__(self, *args, **kwargs):
         order = kwargs.pop('order')
@@ -100,9 +117,20 @@ class OrderPositionAddForm(forms.Form):
         else:
             del self.fields['addon_to']
 
+        if order.event.has_subevents:
+            self.fields['subevent'].queryset = order.event.subevents.all()
+        else:
+            del self.fields['subevent']
+
 
 class OrderPositionChangeForm(forms.Form):
     itemvar = forms.ChoiceField()
+    subevent = SubEventChoiceField(
+        SubEvent.objects.none(),
+        label=pgettext_lazy('subevent', 'New date'),
+        required=True,
+        empty_label=None
+    )
     price = forms.DecimalField(
         required=False,
         max_digits=10, decimal_places=2,
@@ -114,6 +142,7 @@ class OrderPositionChangeForm(forms.Form):
         choices=(
             ('product', 'Change product'),
             ('price', 'Change price'),
+            ('subevent', 'Change event date'),
             ('cancel', 'Remove product')
         )
     )
@@ -131,9 +160,15 @@ class OrderPositionChangeForm(forms.Form):
                 pass
 
             initial['price'] = instance.price
+        initial['subevent'] = instance.subevent
 
         kwargs['initial'] = initial
         super().__init__(*args, **kwargs)
+        if instance.order.event.has_subevents:
+            self.fields['subevent'].instance = instance
+            self.fields['subevent'].queryset = instance.order.event.subevents.all()
+        else:
+            del self.fields['subevent']
         choices = []
         for i in instance.order.event.items.prefetch_related('variations').all():
             pname = str(i.name)
@@ -142,11 +177,13 @@ class OrderPositionChangeForm(forms.Form):
             variations = list(i.variations.all())
             if variations:
                 for v in variations:
+                    p = get_price(i, v, voucher=instance.voucher, subevent=instance.subevent)
                     choices.append(('%d-%d' % (i.pk, v.pk),
-                                    '%s – %s (%s %s)' % (pname, v.value, localize(v.price),
+                                    '%s – %s (%s %s)' % (pname, v.value, localize(p),
                                                          instance.order.event.currency)))
             else:
-                choices.append((str(i.pk), '%s (%s %s)' % (pname, localize(i.default_price),
+                p = get_price(i, None, voucher=instance.voucher, subevent=instance.subevent)
+                choices.append((str(i.pk), '%s (%s %s)' % (pname, localize(p),
                                                            instance.order.event.currency)))
         self.fields['itemvar'].choices = choices