"""Database engine and session factory."""

from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.orm import DeclarativeBase, sessionmaker

from app.config import settings

engine = create_async_engine(settings.database_url, echo=False)

async_session = sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


class Base(DeclarativeBase):
    pass


async def get_db():
    """Dependency: yield a database session."""
    async with async_session() as session:
        yield session