UPD: change grace period for purging registration and participant data.

dav_registration/models.py

@@ -2,7 +2,6 @@
 from __future__ import unicode_literals
 import datetime
 import logging
-import uuid
 from django.db import models
 from django.urls import reverse
 from django.utils import timezone
@@ -17,7 +16,6 @@ from . import signals
 logger = logging.getLogger(__name__)
 
 midnight = datetime.time(00, 00, 00)
-one_day = datetime.timedelta(1)
 
 
 @python_2_unicode_compatible
@@ -150,4 +148,18 @@ Anmerkung:
             last_day = event.alt_first_day
         else:
             last_day = event.first_day
-        return timezone.make_aware(datetime.datetime.combine(last_day + one_day * 7, midnight))
+
+        april = datetime.date(last_day.year, 4, 1)
+        july = datetime.date(last_day.year, 7, 1)
+        july_nextyear = datetime.date(last_day.year + 1, 7, 1)
+        october = datetime.date(last_day.year, 10, 1)
+        january_nextyear = datetime.date(last_day.year + 1, 1, 1)
+
+        if last_day < april:
+            purge_date = july
+        elif last_day < october:
+            purge_date = january_nextyear
+        else:
+            purge_date = july_nextyear
+
+        return timezone.make_aware(datetime.datetime.combine(purge_date, midnight))