import { defineEventHandler, readBody } from 'h3'
import { saveCaptcha } from '../../utils/guard'

const SLIDER_SIZE = 42
const MIN_W = 240
const MAX_W = 480

/**
 * 生成滑块拼图验证码 challenge。
 * 前端量取自身宽度后传入，后端在该宽度内随机生成缺口 X 坐标作为答案。
 * 返回 token + puzzleX(缺口位置，前端用于渲染) + width + size。
 */
export default defineEventHandler(async (event) => {
  const body = (await readBody(event).catch(() => ({}))) as Record<string, any>
  const width = Math.min(Math.max(Number(body?.width) || 320, MIN_W), MAX_W)
  const token = globalThis.crypto.randomUUID()
  const answer = Math.floor(Math.random() * (width - SLIDER_SIZE * 2)) + SLIDER_SIZE
  await saveCaptcha(token, answer)
  return { token, puzzleX: answer, width, size: SLIDER_SIZE }
})