from sqlalchemy.orm import Session
from app.models.coupon import CouponDB,UserCouponDB
from app.models.user import UserDB
from datetime import datetime

class CouponManager:
    def __init__(self, db: Session):
        self.db = db

    # 发放优惠券
    def add_coupon(
        self,
        user_id: int,
        coupon_id: int,
        count: int,
        expire_time: datetime
    ):
        try:
            # 检查优惠券是否存在
            coupon = self.db.query(CouponDB).filter(CouponDB.id == coupon_id).first()
            if not coupon:
                raise ValueError("优惠券不存在")
            
            # 检查用户是否存在
            user = self.db.query(UserDB).filter(UserDB.userid == user_id).first()
            if not user:
                raise ValueError("用户不存在")
            
            for _ in range(count):  
                # 发放优惠券
                user_coupon = UserCouponDB(
                    user_id=user_id,
                    coupon_id=coupon_id,
                    coupon_name=coupon.name,
                    coupon_amount=coupon.amount,
                    coupon_type=coupon.coupon_type,
                    expire_time=expire_time,
                )
                self.db.add(user_coupon)
            
            self.db.commit()
        except Exception as e:
            self.db.rollback()
            raise e