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

# 创建带连接池监控的引擎
engine = create_engine(
    settings.DATABASE_URL,
    poolclass=QueuePool,
    pool_pre_ping=True,
    echo=False,  # 生产环境建议关闭SQL日志
    pool_size=400,
    max_overflow=600,
    pool_timeout=60,  # 增加超时时间到60秒
    pool_recycle=3600,  # 1小时回收连接
    pool_reset_on_return='commit'  # 归还连接时重置状态
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()

def get_db():
    """数据库依赖注入函数"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

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