from django.db import models
from django.contrib.auth.models import User, Group, Permission
from django.contrib.contenttypes.models import ContentType
from django.db.models.signals import post_save
from django.urls import reverse
from django.dispatch import receiver
from django.core import validators


class SchoolProfile(models.Model):
    """Ajoute un champ pour distinguer les groupes écoles des autres."""
    group = models.OneToOneField(
        Group,
        on_delete=models.CASCADE,
        related_name="school",
    )
    admins = models.OneToOneField(
        Group,
        on_delete=models.SET_NULL,
        related_name="admin_of",
        null=True
    )
    phone = models.CharField(
        max_length=10,
        help_text="Visible uniquement des administrateurs",
        verbose_name="Numéro de téléphone pour contacter le responsable des productions",
        blank=False,
        null=True,
        validators=[
            validators.RegexValidator('^[0-9]{10}$',
            "Veuillez entrer un numéro à 10 chiffres."),
        ]
    )

    def __str__(self):
        return self.group.name

    def get_absolute_url(self):
        return reverse("users:school", kwargs={'pk':self.pk})

    def save(self, *args, **kwargs):
        viewing_right, _ = Permission.objects.get_or_create(
            codename='view_' + str(self.group.pk),
            name='Peut voir ' + str(self.group.pk),
            content_type=ContentType.objects.get_for_model(SchoolProfile)
        )
        if viewing_right not in self.group.permissions.all():
            self.group.permissions.add(viewing_right)
            self.group.save()
        admins,_ = Group.objects.get_or_create(name='admins')
        admins.permissions.add(viewing_right)
        super().save(*args, **kwargs)


@receiver(post_save, sender=SchoolProfile)
def update_permissions_school(sender, instance, **kwargs):
    instance.admins,admin_created = Group.objects.get_or_create(name=str(instance.group.pk)+'_admins')
    admin_right,_ = Permission.objects.get_or_create(
        codename='manage_' + str(instance.group.pk),
        name="Administrateur de l'école " + str(instance.group.pk),
        content_type=ContentType.objects.get_for_model(SchoolProfile)
    )
    admins,_ = Group.objects.get_or_create(name='admins')
    admins.permissions.add(admin_right)
    if admin_created:
        instance.save(update_fields=['admins'])
        instance.admins.permissions.add(admin_right)
        instance.admins.save()


class UserProfile(models.Model):
    """Profil d'un utilisateur"""
    school = models.ForeignKey(SchoolProfile, on_delete=models.SET_NULL, null=True)
    user = models.OneToOneField(User, on_delete=models.CASCADE)


@receiver(post_save, sender=UserProfile)
def update_groups(sender, instance, **kwargs):
    instance.user.groups.add(instance.school.group)


@receiver(post_save, sender=User)
def update_permission_user(sender, instance, **kwargs):
    perm,_ = Permission.objects.get_or_create(
        codename='manage_'+str(instance.pk),
        name='Peut administrer ' + instance.username,
        content_type=ContentType.objects.get_for_model(User)
    )
    instance.user_permissions.add(perm)
    admins,_ = Group.objects.get_or_create(name='admins')
    admins.permissions.add(perm)