"""工作单元(Unit of Work):统一事务边界。

使用方式:
    async with get_uow() as uow:
        await uow.session.get(Match, 1)
        await uow.commit()
"""
from __future__ import annotations

from collections.abc import AsyncIterator
from contextlib import asynccontextmanager

from src.db.base import AsyncSessionLocal


@asynccontextmanager
async def get_uow() -> AsyncIterator[AsyncSessionLocal]:
    """创建新的工作单元(用于非路由上下文)。

    用法:
        async with get_uow() as session:
            await session.get(...)
            # 退出时自动 commit(无异常) 或 rollback(有异常)
    """
    session = AsyncSessionLocal()
    try:
        yield session
        await session.commit()
    except Exception:
        await session.rollback()
        raise
    finally:
        await session.close()