"""
数据库连接配置
使用 SQLAlchemy 2.0 同步方式
"""
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from typing import Generator

from .config import settings


# 创建数据库引擎
engine = create_engine(
    settings.DATABASE_URL,
    pool_pre_ping=True,
    pool_recycle=3600,
    echo=False
)

# 创建会话工厂
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# 创建基类
Base = declarative_base()


def get_db() -> Generator:
    """
    数据库会话依赖注入
    用于 FastAPI 的依赖注入系统
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()