Fix timezone handling

aleksis/apps/alsijil/models.py

@@ -574,8 +574,8 @@ class Documentation(CalendarEvent):
                     existing_documentations := (
                         event_reference_obj := event["REFERENCE_OBJECT"]
                     ).documentation.filter(
-                        datetime_start=event["DTSTART"].dt.replace(tzinfo=timezone.utc),
-                        datetime_end=event["DTEND"].dt.replace(tzinfo=timezone.utc),
+                        datetime_start=event["DTSTART"].dt,
+                        datetime_end=event["DTEND"].dt,
                     )
                 ).exists()
                 else cls(

aleksis/apps/alsijil/schema/documentation.py

@@ -171,9 +171,8 @@ class DocumentationBatchCreateOrUpdateMutation(graphene.Mutation):
             # Timezone removal is necessary due to ISO style offsets are no valid timezones.
             # Instead, we take the timezone from the lesson_event and save it in a dedicated field.
             obj = Documentation.objects.create(
-                datetime_start=datetime.fromisoformat(datetime_start).replace(tzinfo=timezone.utc),
-                datetime_end=datetime.fromisoformat(datetime_end).replace(tzinfo=timezone.utc),
-                timezone=lesson_event.timezone,
+                datetime_start=datetime.fromisoformat(datetime_start).astimezone(lesson_event.timezone),
+                datetime_end=datetime.fromisoformat(datetime_end).astimezone(lesson_event.timezone),
                 lesson_event=lesson_event,
                 course=lesson_event.course,
                 subject=lesson_event.subject,