from sqlalchemy import create_engine, MetaData
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from .config import settings

engine = create_engine(settings.DATABASE_URL, pool_pre_ping=True, echo=False, pool_size=30, max_overflow=60, pool_timeout=30, pool_recycle=3600)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

def init_db():
    """初始化数据库表"""
    Base.metadata.create_all(bind=engine)