"""
数据库连接和会话管理
"""
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from sqlalchemy.orm.session import Session
from backend.config import get_database_url,DATABASE_CONFIG

# 创建数据库引擎
engine = create_engine(
    get_database_url(),
    pool_pre_ping=True,
    pool_recycle=3600,
    echo=False  # 设置为True可以看到SQL语句
)

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

# 声明基类
Base = declarative_base()

def get_db():
    """获取数据库会话"""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

def init_db():
    """初始化数据库表"""
    from backend.models import Student, RollCallRecord, ScoreRecord
    from os import getenv
    if(mod:=getenv("DEV_MOD","DEV")):
        if(mod=="TEST"):
            Base.metadata.drop_all(bind=engine)
            print("已清空测试数据库表")
    Base.metadata.create_all(bind=engine)