Cancel all lessons on group absences

aleksis/apps/untis/util/mysql/importers/absences.py

 import logging
 from enum import Enum
 
+from django.db.models import Count
 from django.utils.translation import gettext as _
 
 from reversion import create_revision, set_comment
 from tqdm import tqdm
 
+from aleksis.apps.chronos.models import LessonEvent
 from aleksis.apps.kolego import models as kolego_models
 from aleksis.apps.lesrooster.models import ValidityRange
+from aleksis.core.models import Group
 
 from .... import models as mysql_models
 from ..util import (
@@ -125,6 +128,42 @@ def import_absences(
             existing_absences.append(import_ref)
             ref[import_ref] = new_absence
 
+        # Cancel all lessons of this group
+        if group:
+            # Search parent groups with match
+            group_qs = Group.objects.annotate(parent_groups_count=Count("parent_groups")).filter(
+                parent_groups_count=1, parent_groups=group
+            )
+
+            # Search lesson events with exact groups or parent groups match
+            qs = LessonEvent.objects.filter(
+                amends__isnull=True, extended_data__event_untis__isnull=True
+            ).filter(
+                pk__in=LessonEvent.objects.annotate(groups_count=Count("groups"))
+                .filter(groups_count=1, groups=group)
+                .values_list("id", flat=True)
+                .union(LessonEvent.objects.filter(groups__in=group_qs).values_list("id", flat=True))
+            )
+
+            affected_events = LessonEvent.get_single_events(
+                datetime_start, datetime_end, request=None, with_reference_object=True, queryset=qs
+            )
+
+            for affected_event in affected_events:
+                ref_object = affected_event["REFERENCE_OBJECT"]
+                amending_event, __ = LessonEvent.objects.update_or_create(
+                    amends=ref_object,
+                    datetime_start=affected_event["DTSTART"].dt,
+                    datetime_end=affected_event["DTEND"].dt,
+                    defaults=dict(cancelled=True),
+                )
+                amending_event.extended_data["cancelled_by_absence_untis"] = import_ref
+                amending_event.save()
+                logging.info(
+                    f"  Cancel lesson event {ref_object.id} from {affected_event['DTSTART'].dt} "
+                    f"to {affected_event['DTEND'].dt} with event {amending_event.id}"
+                )
+
     # Delete all no longer existing absences
     for a in kolego_models.Absence.objects.filter(
         extended_data__import_ref_untis__isnull=False,