from sqlalchemy import Column, DateTime
from sqlalchemy.ext.declarative import declared_attr
from datetime import datetime

from app.db.session import Base  # Re-export Base # noqa: F401


class TimestampMixin:
    """Mixin that adds created_at and updated_at columns to models."""
    
    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
    updated_at = Column(
        DateTime, 
        default=datetime.utcnow,
        onupdate=datetime.utcnow,
        nullable=False
    )


class TableNameMixin:
    """Mixin that automatically sets the table name based on the class name."""
    
    @declared_attr
    def __tablename__(cls) -> str:
        return cls.__name__.lower()