Carry absences to all following lessons on save. Closes #17.

biscuit/apps/alsijil/model_extensions.py

+from datetime import date
+from typing import Optional
+
 from django.db.models import Exists, OuterRef
 
 from biscuit.apps.chronos.models import Lesson, LessonPeriod
@@ -22,6 +25,28 @@ def lesson_periods_as_teacher(self):
     return LessonPeriod.objects.filter(lesson__teachers=self)
 
 
+@Person.method
+def mark_absent(self, day: date, starting_period: Optional[int] = 0, absent=True, excused=False):
+    wanted_week = CalendarWeek.from_date(day)
+
+    # Get all lessons of this person on the specified day
+    lesson_periods = self.lesson_periods_as_participant.on_day(
+        day
+    ).filter(
+        period__period__gte=starting_period
+    )
+
+    # Create and update all personal notes for the discovered lesson periods
+    for lesson_period in lesson_periods:
+        PersonalNote.objects.update_or_create(
+            person=self,
+            lesson_period=lesson_period,
+            week=wanted_week.week,
+            absent=absent,
+            excused=excused
+        )
+
+
 @LessonPeriod.method
 def personal_notes(self, wanted_week: CalendarWeek):
     # Find all persons in the associated groups that do not yet have a personal note for this lesson

biscuit/apps/alsijil/views.py

@@ -14,7 +14,7 @@ from biscuit.apps.chronos.util import CalendarWeek
 from biscuit.core.models import Group, Person
 
 from .forms import LessonDocumentationForm, PersonalNoteFormSet, SelectForm
-from .models import LessonDocumentation, PersonalNote
+from .models import LessonDocumentation
 
 
 @login_required
@@ -57,8 +57,18 @@ def lesson(request: HttpRequest, year: Optional[int] = None, week: Optional[int]
     if request.method == 'POST':
         if lesson_documentation_form.is_valid():
             lesson_documentation_form.save()
+
         if personal_note_formset.is_valid():
-            personal_note_formset.save()
+            instances = personal_note_formset.save()
+
+            # Iterate over personal notes and carry changed absences to following lessons
+            for instance in instances:
+                instance.person.mark_absent(
+                    wanted_week[lesson_period.period.weekday],
+                    lesson_period.period.period+1,
+                    instance.absent,
+                    instance.excused
+                )
 
     context['lesson_documentation'] = lesson_documentation
     context['lesson_documentation_form'] = lesson_documentation_form