"""
数据库连接配置
"""
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import declarative_base
from sqlalchemy import event, text
from app.config import settings

# 创建异步引擎
engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    future=True,
    pool_size=20,  # 增加连接池大小
    max_overflow=40,
    pool_pre_ping=True
)

# 创建异步会话工厂
AsyncSessionLocal = async_sessionmaker(
    engine,
    class_=AsyncSession,
    expire_on_commit=False,
    autocommit=False,
    autoflush=False
)

# 声明基类
Base = declarative_base()


async def get_db():
    """获取数据库会话"""
    async with AsyncSessionLocal() as session:
        try:
            yield session
        finally:
            await session.close()


async def init_db():
    """初始化数据库表"""
    async with engine.begin() as conn:
        # PostgreSQL 不需要 WAL 设置
        await conn.run_sync(Base.metadata.create_all)


async def close_db():
    """关闭数据库连接"""
    await engine.dispose()