"""
数据库连接和会话管理
"""

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

logger = logging.getLogger(__name__)

# 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()


async def resolve_user_id(user_id_str: str, db_session: AsyncSession) -> int:
    """
    将用户ID字符串转换为整数ID。
    对于guest用户（如 "guest_xxx"），在数据库中查找或创建对应的用户记录。
    """
    try:
        return int(user_id_str)
    except (TypeError, ValueError):
        from models.database import User
        result = await db_session.execute(
            select(User).where(User.uid == user_id_str)
        )
        user = result.scalar_one_or_none()
        if user:
            return user.id
        # 创建新的guest用户并立即提交，确保后续连接能查到
        new_user = User(
            uid=user_id_str,
            username=user_id_str,
            nickname=user_id_str,
            role=1
        )
        db_session.add(new_user)
        await db_session.flush()
        await db_session.commit()
        logger.info(f"Created guest user: uid={user_id_str}, id={new_user.id}")
        return new_user.id