from fastapi import HTTPException
from ..db import get_connection
from ..utils.jwt_handler import verify_token

def validate_admin(token):
    try:
        payload = verify_token(token)
        connection = get_connection()
        cursor = connection.cursor(dictionary=True)
        cursor.execute("SELECT user_type FROM users WHERE username = %s", (payload['sub'],))
        user = cursor.fetchone()
        if not user or user['user_type'] != 'admin':
            raise HTTPException(status_code=403, detail="权限不足")
        return True
    except Exception as e:
        raise HTTPException(status_code=401, detail=str(e))

def create_coupon_service(token: str, **coupon_data):
    validate_admin(token)
    connection = get_connection()
    try:
        cursor = connection.cursor()
        valid_from = coupon_data['valid_from'].replace('T', ' ')
        valid_to = coupon_data['valid_to'].replace('T', ' ')

        cursor.execute("""
            INSERT INTO coupons (
                coupon_code, discount_type, discount_amount, 
                min_order_amount, valid_from, valid_to, quantity
            ) VALUES (%s, %s, %s, %s, %s, %s, %s)
        """, (
            coupon_data['coupon_code'],
            coupon_data['discount_type'],
            coupon_data['discount_amount'],
            coupon_data.get('min_order_amount'),
            valid_from,
            valid_to,
            coupon_data['quantity']
        ))
        connection.commit()
        return {"message": "优惠券创建成功"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

def get_coupons_service(token: str):
    validate_admin(token)
    connection = get_connection()
    cursor = connection.cursor(dictionary=True)
    cursor.execute("SELECT * FROM coupons")
    return cursor.fetchall()

def issue_coupon_service(token: str, coupon_id: int, user_id: int):
    validate_admin(token)
    connection = get_connection()
    try:
        cursor = connection.cursor(dictionary=True)


        # 检查优惠券是否存在

        cursor.execute("""
            INSERT INTO user_coupons (user_id, coupon_id)
            VALUES (%s, %s)
        """, (user_id, coupon_id))

        # 检查库存
        cursor.execute("SELECT quantity FROM coupons WHERE coupon_id = %s", (coupon_id,))
        coupon = cursor.fetchone()
        if not coupon or coupon['quantity'] <= 0:
            raise HTTPException(status_code=400, detail="优惠券库存不足")

         # 减少库存
        cursor.execute("""
            UPDATE coupons SET quantity = quantity - 1 
            WHERE coupon_id = %s
        """, (coupon_id,))
        connection.commit()
        return {"message": "优惠券发放成功"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

def delete_coupon_service(token: str, coupon_id: int):
    validate_admin(token)
    connection = get_connection()
    try:
        cursor = connection.cursor()
        cursor.execute("DELETE FROM coupons WHERE coupon_id = %s", (coupon_id,))
        connection.commit()
        return {"message": "优惠券删除成功"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))