08Captcha slot — a widget that computes selection match ratio to set border color and button state

<main class="stage">
<section class="wrap" id="wrap">
  <p class="eyebrow">Human check</p>
  <div class="grid" id="grid">
    <div class="tile" data-index="0"></div>
    <div class="tile" data-index="1"></div>
    <div class="tile" data-index="2"></div>
    <div class="tile" data-index="3"></div>
    <div class="tile" data-index="4"></div>
    <div class="tile" data-index="5"></div>
    <div class="tile" data-index="6"></div>
    <div class="tile" data-index="7"></div>
    <div class="tile" data-index="8"></div>
  </div>
  <p class="hint">Match rate <span id="matchPercent">0</span>%</p>
  <button type="button" class="btn" id="submitBtn" disabled>Confirm</button>
</section>
</main>

@use "../../../../site/static/demo-tokens" as *;

$duration: $dur-loop;
$easing: $ease-out;
$color: $subject-blue-deep;

@include stage($stage-paper);

.wrap {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-2;
}

.wrap::before {
  content: "";
  position: absolute;
  inset: -$sp-3;
  border-radius: $r-card;
  background: radial-gradient(circle, rgba($color, .14), transparent 70%);
  animation: scanPulse $duration $easing infinite;
  z-index: -1;
}

.eyebrow {
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba($subject-ink, .08);
  color: $subject-ink;
  font-weight: 600;
  font-size: 11px;
  letter-spacing: .04em;
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, 40px);
  grid-template-rows: repeat(3, 40px);
  gap: $sp-1;
}

.tile {
  border-radius: $r-sm;
  border: 2px solid rgba($subject-ink, .18);
  background: $subject-cream;
  transition: border-color .15s $easing, background-color .15s $easing;
}

.tile.isPicked {
  border-color: $color;
  background: rgba($color, .12);
}

.hint {
  margin: 0;
  color: $subject-ink;
  font-weight: 600;
  font-size: 13px;
}

.btn {
  border: none;
  border-radius: $r-control;
  padding: $sp-2 $sp-6;
  background: $color;
  color: $subject-cream;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: opacity .15s $easing;
}

.btn:disabled {
  opacity: .4;
  cursor: not-allowed;
}

@keyframes scanPulse {
  0%, 100% { opacity: .35; transform: scale(.92); }
  50% { opacity: .8; transform: scale(1.05); }
}

@media (max-width: 340px) {
  .wrap { gap: $sp-1; }
  .grid { grid-template-columns: repeat(3, 28px); grid-template-rows: repeat(3, 28px); }
  .hint { font-size: 11px; }
  .btn { font-size: 11px; padding: $sp-1 $sp-4; }
}

@media (prefers-reduced-motion: reduce) {
  .wrap::before { animation: none; opacity: .5; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.wrap {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.wrap::before {
  content: "";
  position: absolute;
  inset: -12px;
  border-radius: 16px;
  background: radial-gradient(circle, rgba(10, 79, 232, 0.14), transparent 70%);
  animation: scanPulse 2s ease-out infinite;
  z-index: -1;
}

.eyebrow {
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.08);
  color: #17141a;
  font-weight: 600;
  font-size: 11px;
  letter-spacing: 0.04em;
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, 40px);
  grid-template-rows: repeat(3, 40px);
  gap: 4px;
}

.tile {
  border-radius: 8px;
  border: 2px solid rgba(23, 20, 26, 0.18);
  background: #fff7e6;
  transition: border-color 0.15s ease-out, background-color 0.15s ease-out;
}

.tile.isPicked {
  border-color: #0a4fe8;
  background: rgba(10, 79, 232, 0.12);
}

.hint {
  margin: 0;
  color: #17141a;
  font-weight: 600;
  font-size: 13px;
}

.btn {
  border: none;
  border-radius: 12px;
  padding: 8px 24px;
  background: #0a4fe8;
  color: #fff7e6;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: opacity 0.15s ease-out;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

@keyframes scanPulse {
  0%, 100% {
    opacity: 0.35;
    transform: scale(0.92);
  }
  50% {
    opacity: 0.8;
    transform: scale(1.05);
  }
}
@media (max-width: 340px) {
  .wrap {
    gap: 4px;
  }
  .grid {
    grid-template-columns: repeat(3, 28px);
    grid-template-rows: repeat(3, 28px);
  }
  .hint {
    font-size: 11px;
  }
  .btn {
    font-size: 11px;
    padding: 4px 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .wrap::before {
    animation: none;
    opacity: 0.5;
  }
}

// 캡차 위젯(08, 아이디어형) — 정답 칸(ANSWER)과 시간이 흐르며 자동으로 골라지는 칸(PICK_ORDER)을
// 매 프레임 다시 비교해 Match rate(matchRatio)을 구하고, 그 값이 기준(MATCH_THRESHOLD)을
// 넘어야 Confirm 버튼을 실제로 활성화한다. 실제 클릭 리스너는 넣지 않는다 — 자동 선택 시뮬레이션만.
// 실키·실서버 요청 없음.
(function () {
  var ANSWER = [1, 3, 5, 7];
  var PICK_ORDER = [1, 4, 3, 7, 5]; // 일부러 오답 4 를 포함한 고정 순서
  var PICK_MS = 350; // 5 * 350 = 1750
  var MATCH_THRESHOLD = 1; // 100% 일치해야 활성화
  var CYCLE_MS = 2000;

  function clamp(v, min, max) { return Math.max(min, Math.min(max, v)); }

  var tiles = Array.prototype.slice.call(document.querySelectorAll('.tile'));
  var matchPercent = document.getElementById('matchPercent');
  var submitBtn = document.getElementById('submitBtn');
  if (!tiles.length || !matchPercent || !submitBtn) return;

  function selectedSoFar(t) {
    var count = clamp(Math.floor(t / PICK_MS), 0, PICK_ORDER.length);
    return PICK_ORDER.slice(0, count);
  }

  function matchRatioOf(selected) {
    var hit = 0;
    for (var i = 0; i < ANSWER.length; i++) {
      if (selected.indexOf(ANSWER[i]) !== -1) hit += 1;
    }
    return clamp(hit / ANSWER.length, 0, 1);
  }

  function apply(t) {
    var selected = selectedSoFar(t);
    tiles.forEach(function (tile) {
      var idx = Number(tile.getAttribute('data-index'));
      tile.classList.toggle('isPicked', selected.indexOf(idx) !== -1);
    });
    var ratio = matchRatioOf(selected);
    matchPercent.textContent = String(Math.round(ratio * 100));
    submitBtn.disabled = ratio < MATCH_THRESHOLD;
  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (reduce) {
    apply(PICK_ORDER.length * PICK_MS);
    return;
  }

  var start = null;
  function loop(ts) {
    if (start === null) start = ts;
    var t = (ts - start) % CYCLE_MS;
    apply(t);
    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);
})();

import { useEffect, useRef } from "react";
import styles from "./CaptchaSlot.module.scss";

// 캡차 위젯(08, 아이디어형) — 정답 칸(ANSWER)과 시간이 흐르며 자동으로 골라지는 칸(PICK_ORDER)을
// 매 프레임 다시 비교해 일치율(matchRatio)을 구하고, 그 값이 기준(MATCH_THRESHOLD)을
// 넘어야 확인 버튼을 실제로 활성화한다. 실제 클릭 리스너는 넣지 않는다 — 자동 선택 시뮬레이션만.
// 실키·실서버 요청 없음.
const ANSWER = [1, 3, 5, 7];
const PICK_ORDER = [1, 4, 3, 7, 5]; // 일부러 오답 4 를 포함한 고정 순서
const PICK_MS = 350; // 5 * 350 = 1750
const MATCH_THRESHOLD = 1; // 100% 일치해야 활성화
const CYCLE_MS = 2000;
const TILE_INDEXES = [0, 1, 2, 3, 4, 5, 6, 7, 8];

function clamp(v: number, min: number, max: number) {
  return Math.max(min, Math.min(max, v));
}

function selectedSoFar(t: number) {
  const count = clamp(Math.floor(t / PICK_MS), 0, PICK_ORDER.length);
  return PICK_ORDER.slice(0, count);
}

function matchRatioOf(selected: number[]) {
  let hit = 0;
  for (let i = 0; i < ANSWER.length; i++) {
    if (selected.indexOf(ANSWER[i]) !== -1) hit += 1;
  }
  return clamp(hit / ANSWER.length, 0, 1);
}

export default function CaptchaSlot() {
  const tileRefs = [
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
    useRef<HTMLDivElement>(null),
  ];
  const matchRef = useRef<HTMLSpanElement>(null);
  const submitRef = useRef<HTMLButtonElement>(null);

  useEffect(() => {
    const tiles = tileRefs.map((r) => r.current);
    const matchEl = matchRef.current;
    const submitEl = submitRef.current;
    if (tiles.some((t) => !t) || !matchEl || !submitEl) return;

    function apply(t: number) {
      const selected = selectedSoFar(t);
      tiles.forEach((tile, idx) => {
        if (!tile) return;
        tile.classList.toggle(styles.isPicked, selected.indexOf(idx) !== -1);
      });
      const ratio = matchRatioOf(selected);
      matchEl!.textContent = String(Math.round(ratio * 100));
      submitEl!.disabled = ratio < MATCH_THRESHOLD;
    }

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (reduce) {
      apply(PICK_ORDER.length * PICK_MS);
      return;
    }

    let start: number | null = null;
    let raf = 0;
    function loop(ts: number) {
      if (start === null) start = ts;
      const t = (ts - start) % CYCLE_MS;
      apply(t);
      raf = requestAnimationFrame(loop);
    }
    raf = requestAnimationFrame(loop);
    return () => cancelAnimationFrame(raf);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <main className={styles.stage}>
      <section className={styles.wrap}>
        <p className={styles.eyebrow}>사람 확인</p>
        <div className={styles.grid}>
          {TILE_INDEXES.map((idx) => (
            <div key={idx} className={styles.tile} ref={tileRefs[idx]} />
          ))}
        </div>
        <p className={styles.hint}>
          일치율 <span ref={matchRef}>0</span>%
        </p>
        <button type="button" className={styles.btn} ref={submitRef} disabled>확인</button>
      </section>
    </main>
  );
}