计算云服务器代金卷

def validate_coupon(coupon_code, order_total):
    # 假设从数据库获取代金券信息
    coupon_info = get_coupon_info_from_db(coupon_code)
    
    if not coupon_info:
        return "无效的代金券代码"
    
    if coupon_info['expiry_date'] < datetime.now():
        return "代金券已过期"
    
    if order_total < coupon_info['min_order_amount']:
        return "订单金额未达到使用条件"
    
    discount_amount = coupon_info['value']
    final_total = order_total - discount_amount
    return f"折扣后总金额: {final_total}"

def get_coupon_info_from_db(coupon_code):
    # 模拟从数据库获取代金券信息
    coupons = {
        "SAVE10": {"value": 10, "min_order_amount": 50, "expiry_date": datetime(2023, 12, 31)},
        "DISCOUNT20": {"value": 20, "min_order_amount": 100, "expiry_date": datetime(2023, 11, 30)}
    }
    return coupons.get(coupon_code)

# 示例调用
print(validate_coupon("SAVE10", 60))  # 输出: 折扣后总金额: 50
print(validate_coupon("DISCOUNT20", 80))  # 输出: 订单金额未达到使用条件