"""
数据库连接和会话管理
"""

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

# 创建异步引擎
# 将数据库URL转换为asyncmy驱动（用于异步操作）
# 首先尝试pymysql到asyncmy的转换，如果失败则尝试mysql到mysql+asyncmy的转换
if 'mysql+pymysql' in settings.DATABASE_URL:
    async_db_url = settings.DATABASE_URL.replace('mysql+pymysql', 'mysql+asyncmy')
else:
    async_db_url = settings.DATABASE_URL.replace('mysql', 'mysql+asyncmy')
    
async_engine = create_async_engine(
    async_db_url,
    echo=settings.DEBUG,
    pool_pre_ping=True
)

# 创建会话工厂
AsyncSessionLocal = async_sessionmaker(
    bind=async_engine,
    class_=AsyncSession,
    expire_on_commit=False
)

async def get_db():
    """获取数据库会话的依赖函数"""
    async with AsyncSessionLocal() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()