models.py

# flake8: noqa: DJ01

from __future__ import annotations

from datetime import date, datetime, time, timedelta
from typing import Dict, Iterator, List, Optional, Tuple, Union

from django.core.exceptions import ValidationError
from django.db import models
from django.db.models import Max, Min, Q
from django.db.models.functions import Coalesce
from django.forms import Media
from django.urls import reverse
from django.utils import timezone
from django.utils.formats import date_format
from django.utils.functional import classproperty
from django.utils.translation import gettext_lazy as _

from cache_memoize import cache_memoize
from calendarweek.django import CalendarWeek, i18n_day_abbr_choices_lazy, i18n_day_name_choices_lazy
from colorfield.fields import ColorField

from aleksis.apps.chronos.managers import (
    AbsenceQuerySet,
    BreakManager,
    CurrentSiteManager,
    EventManager,
    EventQuerySet,
    ExtraLessonManager,
    ExtraLessonQuerySet,
    GroupPropertiesMixin,
    HolidayQuerySet,
    LessonPeriodManager,
    LessonPeriodQuerySet,
    LessonSubstitutionManager,
    LessonSubstitutionQuerySet,
    SupervisionManager,
    SupervisionQuerySet,
    SupervisionSubstitutionManager,
    TeacherPropertiesMixin,
    ValidityRangeQuerySet,
)
from aleksis.apps.chronos.mixins import (
    ValidityRangeRelatedExtensibleModel,
    WeekAnnotationMixin,
    WeekRelatedMixin,
)
from aleksis.apps.chronos.util.date import get_current_year
from aleksis.apps.chronos.util.format import format_m2m
from aleksis.core.managers import CurrentSiteManagerWithoutMigrations
from aleksis.core.mixins import (
    ExtensibleModel,
    GlobalPermissionModel,
    SchoolTermRelatedExtensibleModel,
)
from aleksis.core.models import DashboardWidget, SchoolTerm
from aleksis.core.util.core_helpers import has_person


class ValidityRange(ExtensibleModel):
    """Validity range model.

    This is used to link data to a validity range.
    """

    objects = CurrentSiteManagerWithoutMigrations.from_queryset(ValidityRangeQuerySet)()

    school_term = models.ForeignKey(
        SchoolTerm,
        on_delete=models.CASCADE,
        verbose_name=_("School term"),
        related_name="validity_ranges",
    )
    name = models.CharField(verbose_name=_("Name"), max_length=255, blank=True)

    date_start = models.DateField(verbose_name=_("Start date"))
    date_end = models.DateField(verbose_name=_("End date"))

    @classmethod
    @cache_memoize(3600)
    def get_current(cls, day: Optional[date] = None):
        if not day:
            day = timezone.now().date()
        try:
            return cls.objects.on_day(day).first()
        except ValidityRange.DoesNotExist:
            return None

    @classproperty
    def current(cls):
        return cls.get_current()

    def clean(self):
        """Ensure there is only one validity range at each point of time."""
        if self.date_end < self.date_start:
            raise ValidationError(_("The start date must be earlier than the end date."))

        if self.school_term:
            if (
                self.date_end > self.school_term.date_end
                or self.date_start < self.school_term.date_start
            ):
                raise ValidationError(_("The validity range must be within the school term."))

        qs = ValidityRange.objects.within_dates(self.date_start, self.date_end)
        if self.pk:
            qs = qs.exclude(pk=self.pk)
        if qs.exists():
            raise ValidationError(
                _("There is already a validity range for this time or a part of this time.")
            )

    def __str__(self):
        return self.name or f"{date_format(self.date_start)}–{date_format(self.date_end)}"

    class Meta:
        verbose_name = _("Validity range")
        verbose_name_plural = _("Validity ranges")
        constraints = [
            # Heads up: Uniqueness per term implies uniqueness per site
            models.UniqueConstraint(
                fields=["school_term", "date_start", "date_end"], name="unique_dates_per_term"
            ),
        ]
        indexes = [
            models.Index(fields=["date_start", "date_end"], name="validity_date_start_date_end")
        ]


class TimePeriod(ValidityRangeRelatedExtensibleModel):
    WEEKDAY_CHOICES = i18n_day_name_choices_lazy()
    WEEKDAY_CHOICES_SHORT = i18n_day_abbr_choices_lazy()

    weekday = models.PositiveSmallIntegerField(
        verbose_name=_("Week day"), choices=i18n_day_name_choices_lazy()
    )
    period = models.PositiveSmallIntegerField(verbose_name=_("Number of period"))

    time_start = models.TimeField(verbose_name=_("Start time"))
    time_end = models.TimeField(verbose_name=_("End time"))

    def __str__(self) -> str:
        return f"{self.get_weekday_display()}, {self.period}."

    @classmethod
    def get_times_dict(cls) -> Dict[int, Tuple[datetime, datetime]]:
        periods = {}
        for period in cls.objects.for_current_or_all().all():
            periods[period.period] = (period.time_start, period.time_end)

        return periods

    def get_date(self, week: Optional[CalendarWeek] = None) -> date:
        if isinstance(week, CalendarWeek):
            wanted_week = week
        else:
            year = getattr(self, "_year", None) or date.today().year
            week_number = getattr(self, "_week", None) or CalendarWeek().week

            wanted_week = CalendarWeek(year=year, week=week_number)

        return wanted_week[self.weekday]

    def get_datetime_start(self, week: Optional[Union[CalendarWeek, int]] = None) -> datetime:
        """Get datetime of lesson start in a specific week."""
        day = self.get_date(week)
        return datetime.combine(day, self.time_start)

    def get_datetime_end(self, week: Optional[Union[CalendarWeek, int]] = None) -> datetime:
        """Get datetime of lesson end in a specific week."""
        day = self.get_date(week)
        return datetime.combine(day, self.time_end)

    @classmethod
    def get_next_relevant_day(
        cls, day: Optional[date] = None, time: Optional[time] = None, prev: bool = False
    ) -> date:
        """Return next (previous) day with lessons depending on date and time."""
        if day is None:
            day = timezone.now().date()

        if time is not None and cls.time_max and not prev:
            if time > cls.time_max:
                day += timedelta(days=1)

        cw = CalendarWeek.from_date(day)

        if day.weekday() > cls.weekday_max:
            if prev:
                day = cw[cls.weekday_max]
            else:
                cw += 1
                day = cw[cls.weekday_min]
        elif day.weekday() < TimePeriod.weekday_min:
            if prev:
                cw -= 1
                day = cw[cls.weekday_max]
            else:
                day = cw[cls.weekday_min]