from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import DeclarativeBase
from config import settings

engine = create_async_engine(settings.database_url, pool_size=10, echo=False)
AsyncSessionLocal = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


class Base(DeclarativeBase):
    pass


async def get_pg_session() -> AsyncSession:
    """FastAPI dependency — yields a DB session and closes it after the request."""
    async with AsyncSessionLocal() as session:
        yield session
