MAKENTNU/web

from django.db import models
from django.db.models import Q
from django.utils import timezone
from django.utils.translation import gettext_lazy as _

from web.modelfields import URLTextField
from web.multilingual.modelfields import MultiLingualTextField


class AnnouncementQuerySet(models.QuerySet):

    def shown(self) -> 'AnnouncementQuerySet[Announcement]':
        """Returns a ``QuerySet`` with only the announcements that are currently shown."""
        now = timezone.localtime()
        return self.filter(
            Q(display_from__lte=now)
            & (Q(display_to__isnull=True) | Q(display_to__gt=now))
        )

    def not_shown(self) -> 'AnnouncementQuerySet[Announcement]':
        """Returns a ``QuerySet`` with only the announcements that are currently not shown."""
        now = timezone.localtime()
        return self.filter(
            Q(display_from__lte=now) & Q(display_to__lte=now)
            | Q(display_from__gt=now)
        )

    def site_wide(self) -> 'AnnouncementQuerySet[Announcement]':
        """Returns a ``QuerySet`` with only the announcements that should be displayed site-wide."""
        return self.filter(site_wide=True)

    def non_site_wide(self) -> 'AnnouncementQuerySet[Announcement]':
        """Returns a ``QuerySet`` with only the announcements that should not be displayed site-wide."""
        return self.filter(site_wide=False)


class Announcement(models.Model):
    """
    Model for general announcements. All announcements are time-based, but can be shown for an indefinite time period if
    there is no end time given. An announcement may also link to another page with more information.
    """

    class Type(models.TextChoices):
        INFO = "I", _("Information")
        WARNING = "W", _("Warning")
        CRITICAL = "C", _("Critical")

    classification = models.CharField(choices=Type.choices, max_length=1, default=Type.INFO,
                                      verbose_name=_("type"))
    site_wide = models.BooleanField(verbose_name=_("site-wide"),
                                    help_text=_("If selected, the announcement will be shown on all pages, otherwise it"
                                                " is only shown on the front page."))
    content = MultiLingualTextField(verbose_name=_("content"))
    link = URLTextField(blank=True, verbose_name=_("link"),
                        help_text=_("An optional link to an information page."))
    display_from = models.DateTimeField(default=timezone.localtime, verbose_name=_("display from"),
                                        help_text=_("The date from which the announcement will be shown."))
    display_to = models.DateTimeField(null=True, blank=True, verbose_name=_("display to"),
                                      help_text=_("The announcement will be shown until this date. If none is given, it"
                                                  " is shown indefinitely."))

    objects = AnnouncementQuerySet.as_manager()

    def __str__(self):
        return f"{self.get_classification_display()}: {self.content}"

    def is_shown(self):
        """Checks if the given reservation is currently shown."""
        return self.display_from <= timezone.localtime() and (
                self.display_to is None or self.display_to > timezone.localtime())