Resolve "Option to hide incomplete substitutions from the plan"

Closes #39 (closed)

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

@@ -8,6 +8,7 @@ from tqdm import tqdm
 
 from aleksis.apps.chronos import models as chronos_models
 from aleksis.apps.chronos.models import ValidityRange
+from aleksis.core.util.core_helpers import get_site_preferences
 
 from .... import models as mysql_models
 from ..util import (
@@ -138,6 +139,17 @@ def import_substitutions(
             for id_ in class_ids:
                 classes.append(classes_ref[id_])
 
+            if get_site_preferences()["untis_mysql__ignore_incomplete_substitutions"]:
+                # Skip incomplete substitutions
+                if (
+                    not room_new
+                    and not subject_new
+                    and not teachers
+                    and not cancelled
+                    and not cancelled_for_teachers
+                ):
+                    continue
+
             if lesson_period:
                 (substitution, created,) = chronos_models.LessonSubstitution.objects.get_or_create(
                     lesson_period=lesson_period, week=week.week, year=week.year