"""Async-Engine und Session-Factory."""

from collections.abc import AsyncGenerator

from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

from app.core.config import settings

engine = create_async_engine(
    str(settings.database_url),
    echo=settings.debug,
    pool_pre_ping=True,
)

SessionLocal = async_sessionmaker(
    bind=engine,
    class_=AsyncSession,
    expire_on_commit=False,
    autoflush=False,
)


async def get_session() -> AsyncGenerator[AsyncSession, None]:
    """FastAPI-Dependency: eine Session pro Request."""
    async with SessionLocal() as session:
        try:
            yield session
        except Exception:
            await session.rollback()
            raise