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/views/orders.py

@@ -16,6 +16,7 @@ from pretix.base.models import (
     CachedFile, CachedTicket, Invoice, InvoiceAddress, Item, ItemVariation,
     Order, Quota, generate_position_secret, generate_secret,
 )
+from pretix.base.models.event import SubEvent
 from pretix.base.services.export import export
 from pretix.base.services.invoices import (
     generate_cancellation, generate_invoice, invoice_pdf, invoice_qualified,
@@ -53,13 +54,6 @@ class OrderList(EventPermissionRequiredMixin, ListView):
         if self.filter_form.is_valid():
             qs = self.filter_form.filter_qs(qs)
 
-        if self.request.GET.get("ordering", "") != "":
-            p = self.request.GET.get("ordering", "")
-            p_admissable = ('-code', 'code', '-email', 'email', '-total', 'total', '-datetime', 'datetime',
-                            '-status', 'status', 'pcnt', '-pcnt')
-            if p in p_admissable:
-                qs = qs.order_by(p)
-
         return qs.distinct()
 
     def get_context_data(self, **kwargs):
@@ -480,7 +474,8 @@ class OrderChange(OrderView):
                 try:
                     ocm.add_position(item, variation,
                                      self.add_form.cleaned_data['price'],
-                                     self.add_form.cleaned_data.get('addon_to'))
+                                     self.add_form.cleaned_data.get('addon_to'),
+                                     self.add_form.cleaned_data.get('subevent'))
                 except OrderError as e:
                     self.add_form.custom_error = str(e)
                     return False
@@ -506,6 +501,8 @@ class OrderChange(OrderView):
                     ocm.change_item(p, item, variation)
                 elif p.form.cleaned_data['operation'] == 'price':
                     ocm.change_price(p, p.form.cleaned_data['price'])
+                elif p.form.cleaned_data['operation'] == 'subevent':
+                    ocm.change_subevent(p, p.form.cleaned_data['subevent'])
                 elif p.form.cleaned_data['operation'] == 'cancel':
                     ocm.cancel(p)
 
@@ -613,7 +610,19 @@ class OverView(EventPermissionRequiredMixin, TemplateView):
 
     def get_context_data(self, **kwargs):
         ctx = super().get_context_data()
-        ctx['items_by_category'], ctx['total'] = order_overview(self.request.event)
+
+        subevent = None
+        if self.request.GET.get("subevent", "") != "" and self.request.event.has_subevents:
+            i = self.request.GET.get("subevent", "")
+            try:
+                subevent = self.request.event.subevents.get(pk=i)
+            except SubEvent.DoesNotExist:
+                pass
+
+        ctx['items_by_category'], ctx['total'] = order_overview(self.request.event, subevent=subevent)
+        ctx['subevent_warning'] = self.request.event.has_subevents and subevent and (
+            self.request.event.orders.filter(payment_fee__gt=0).exists()
+        )
         return ctx