from sqlalchemy import Column, Integer, DateTime, Boolean, String, JSON, func
from sqlalchemy.orm import declarative_mixin, declarative_base

Base = declarative_base()

@declarative_mixin
class CRUDMixin:
    id = Column(Integer, primary_key=True)
    created_at = Column(DateTime, default=func.now())
    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())

    def as_dict(self):
        return {c.name: getattr(self, c.name) for c in self.__table__.columns}

class Version(Base):
    __tablename__ = "versions"

    id = Column(Integer, primary_key=True)
    model_name = Column(String, nullable=False)
    object_id = Column(Integer, nullable=False)
    change_type = Column(String, nullable=False)
    data = Column(JSON, nullable=True)
    timestamp = Column(DateTime, default=func.now())

    actor = Column(String, nullable=True)
    metadata = Column(JSON, nullable=True)