from django.db import models

class Entity(models.Model):
    name = models.TextField(null=True, blank=True, default=None)
    details = models.TextField(null=True, blank=True, default=None)

class EntityClosure(models.Model):
    ancestor = models.ForeignKey(Entity, related_name="dset")
    descendant = models.ForeignKey(Entity, related_name="aset")
    depth = models.PositiveSmallIntegerField()

class Tag(Entity):
    def __str__(self):
        return self.name

class TaggedEntity(models.Model):
    entity = models.ForeignKey(Entity,related_name="tags")
    tag = models.ForeignKey(Tag,related_name="entities")

# Para testar
if not Entity.objects.count():
    e = Entity.objects.create(name="teste")
    t1 = Tag.objects.create(name="Tag 1")
    t2 = Tag.objects.create(name="Tag 2")
    t11 = Tag.objects.create(name="Tag 1.1")
    EntityClosure.objects.create(ancestor=t1, descendant=t1, depth=0)
    EntityClosure.objects.create(ancestor=t2, descendant=t2, depth=0)
    EntityClosure.objects.create(ancestor=t11, descendant=t11, depth=0)
    EntityClosure.objects.create(ancestor=t1, descendant=t11, depth=1)
    TaggedEntity.objects.create(entity=e, tag=t11)