用户填到一半跑了怎么办

from aiogram import Router, Ffrom aiogram.filters import Command, StateFilterfrom aiogram.fsm.context import FSMContextfrom aiogram.fsm.state import State, StatesGroupfrom aiogram.types import Messageimport storageREWARDS = {    "贴纸": 30,    "会员一天": 100,    "定制头像": 500,}router = Router()class Redeem(StatesGroup):    """兑换流程的两步。"""    choosing = State()      # 等他说要换什么    confirming = State()    # 等他确认

@router.message(Command("redeem"))async def redeem_start(message: Message, state: FSMContext) -> None:    if message.from_user is None:        return    row = storage.get_user(message.from_user.id)    points = row[1] if row else 0    cheapest = min(REWARDS.values())    # 进流程之前先挡住不可能成功的情况，别让人白填一遍    if points < cheapest:        await message.answer(            f"你只有 {points} 分，最便宜的要 {cheapest} 分。\n"            f"发 /checkin 多签几天。"        )        return    menu = "\n".join(f"  {k}（{v} 分）" for k, v in REWARDS.items())    await state.set_state(Redeem.choosing)    await message.answer(        f"你有 {points} 分。兑换什么？直接回名字：\n{menu}\n\n"        f"不想换了发 /cancel"    )

@router.message(Redeem.choosing)async def redeem_choose(message: Message, state: FSMContext) -> None:    item = (message.text or "").strip()    if item not in REWARDS:        await message.answer("没有这个。照着上面的名字回一个，或者 /cancel")        return          # 状态不变，他可以重说一次    cost = REWARDS[item]    row = storage.get_user(message.from_user.id)    points = row[1] if row else 0    if cost > points:        await message.answer(f"「{item}」要 {cost} 分，你只有 {points} 分。换一个？")        return    await state.update_data(item=item, cost=cost)   # 存进这个用户的流程数据    await state.set_state(Redeem.confirming)    await message.answer(f"确认用 {cost} 分换「{item}」？回 是 或 否")

@router.message(Redeem.confirming)async def redeem_confirm(message: Message, state: FSMContext) -> None:    answer = (message.text or "").strip()    if answer not in {"是", "否"}:        await message.answer("回 是 或 否")        return    if answer == "否":        await state.clear()        await message.answer("那就算了")        return    data = await state.get_data()    await state.clear()        # 先清状态：扣分失败也不能让他卡在流程里    left = storage.spend(message.from_user.id, data["cost"])    if left is None:        await message.answer("分不够了，可能刚才在别处花掉了。再来一次吧")        return    await message.answer(f"兑换成功：{data['item']}\n剩余 {left} 分")

def spend(user_id: int, cost: int) -> int | None:    """扣分。成功返回剩余分；分不够返回 None。"""    with connect() as conn:        cur = conn.execute(            "UPDATE users SET points = points - ? "            "WHERE user_id = ? AND points >= ?",   # ← 关键在这个条件            (cost, user_id, cost),        )        if cur.rowcount == 0:            return None        # 一行都没改到 = 分不够        return conn.execute(            "SELECT points FROM users WHERE user_id = ?", (user_id,)        ).fetchone()[0]

@router.message(Command("cancel"), StateFilter("*"))async def cancel_any(message: Message, state: FSMContext) -> None:    if await state.get_state() is None:        await message.answer("你没在做什么需要取消的事")        return    await state.clear()    await message.answer("已取消")