from django.conf import settings
from django.db import models


class OptionalAuditableMixin(models.Model):
    """Mixin for models that want explicit auditable fields."""

    usuario_creacion = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="+",
    )
    fecha_creacion = models.DateTimeField(auto_now_add=True, null=True, blank=True)
    usuario_actualizacion = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="+",
    )
    fecha_actualizacion = models.DateTimeField(auto_now=True, null=True, blank=True)

    class Meta:
        abstract = True