from sqlalchemy import Column, Integer, Boolean, ForeignKey

from ._base import Entity, entity_types_registry


if not entity_types_registry.get('Device'):

    class Device(Entity):
        __tablename__ = 'device'

        id = Column(
            Integer, ForeignKey(Entity.id, ondelete='CASCADE'), primary_key=True
        )
        reachable = Column(Boolean, default=True)

        __mapper_args__ = {
            'polymorphic_identity': __tablename__,
        }

    entity_types_registry['Device'] = Device
else:
    Device = entity_types_registry['Device']