model_extensions.py

from datetime import date

from django.db.models import Exists, F, OuterRef

from biscuit.apps.chronos.models import LessonPeriod
from biscuit.apps.chronos.util import CalendarWeek
from biscuit.core.models import Group, Person

from .models import PersonalNote


@Person.method
def mark_absent(
    self,
    day: date,
    from_period: int = 0,
    absent: bool = True,
    excused: bool = False,
    remarks: str = "",
):
    """ Mark a person absent for all lessons in a day, optionally starting with
    a selected period number.
    
    This function creates `PersonalNote` objects for every `LessonPeriod` the person
    participates in on the selected day and marks them as absent/excused.

    ..note:: Only available when BiscuIT-App-Alsijil is installed.

    :Date: 2019-11-10
    :Authors:
        - Dominik George <dominik.george@teckids.org>
    """

    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=from_period
    )

    # Create and update all personal notes for the discovered lesson periods
    for lesson_period in lesson_periods:
        personal_note, created = PersonalNote.objects.update_or_create(
            person=self,
            lesson_period=lesson_period,
            week=wanted_week.week,
            defaults={"absent": absent, "excused": excused},
        )

        if remarks:
            if personal_note.remarks:
                personal_note.remarks += "; %s" % remarks
            else:
                personal_note.remarks = remarks
            personal_note.save()


@LessonPeriod.method
def get_personal_notes(self, wanted_week: CalendarWeek):
    """ Get all personal notes for that lesson in a specified week.
    
    Returns all linked `PersonalNote` objects, filtered by the given weeek,
    creating those objects that haven't been created yet.
    
    ..note:: Only available when BiscuIT-App-Alsijil is installed.

    :Date: 2019-11-09
    :Authors:
        - Dominik George <dominik.george@teckids.org>
    """

    # Find all persons in the associated groups that do not yet have a personal note for this lesson
    missing_persons = Person.objects.annotate(
        no_personal_notes=~Exists(
            PersonalNote.objects.filter(
                week=wanted_week.week, lesson_period=self, person__pk=OuterRef("pk")
            )
        )
    ).filter(
        member_of__in=Group.objects.filter(pk__in=self.lesson.groups.all()),
        is_active=True,
        no_personal_notes=True,
    )

    # Create all missing personal notes
    PersonalNote.objects.bulk_create(
        [
            PersonalNote(person=person, lesson_period=self, week=wanted_week.week)
            for person in missing_persons
        ]
    )

    return PersonalNote.objects.select_related("person").filter(
        lesson_period=self, week=wanted_week.week
    )