"""SQLAlchemy 异步引擎和 session 工厂。"""

from __future__ import annotations

from contextlib import asynccontextmanager

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

from fastapi_admin.config import ASYNCPG_DATABASE_URL

_engine = create_async_engine(ASYNCPG_DATABASE_URL, echo=False, pool_size=20, max_overflow=10)

_AsyncSessionFactory = async_sessionmaker(_engine, class_=AsyncSession, expire_on_commit=False)


@asynccontextmanager
async def GetAsyncSession():
    """获取异步数据库 session（上下文管理器）。"""
    async with _AsyncSessionFactory() as session:
        yield session
        await session.commit()