from sqlalchemy.ext.declarative import declarative_base, declared_attr
from sqlalchemy.orm import Mapped, mapped_column
import datetime

Base = declarative_base()


class DbCommon(Base):
    __abstract__ = True
    id: Mapped[int] = mapped_column(primary_key=True)
    create_time: Mapped[datetime.datetime] = mapped_column(default=datetime.datetime.utcnow())
    update_time: Mapped[datetime.datetime] = mapped_column(default=datetime.datetime.utcnow(), onupdate=datetime.datetime.utcnow())

    def keys(self):
        return ["id", "create_time", "update_time"]


    @declared_attr
    def __tablename__(cls):
        return cls.__name__.lower()