09問題の有効時間がリングで縮み、尽きると更新アイコンが回って新しい問題に替わる確認

<main class="stage">
<div class="cp is-demo" id="cp">
  <canvas class="cp__canvas" data-role="canvas" width="480" height="300" tabindex="0" aria-label="問題の有効時間がリングで縮み、尽きると更新アイコンが回って新しい問題に替わる確認"></canvas>
  <p class="cp__status" data-role="status" aria-live="polite">デモを準備中</p>
  <button class="cp__btn" data-role="btn" type="button">一時停止</button>
</div>
</main>

@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);

.cp {
  position: relative;
  width: min(92vw, calc(160vh - 12.8vw));
  aspect-ratio: 480 / 300;
  margin: 0 auto;
  border-radius: $r-card;
  overflow: hidden;
  box-shadow: $shadow-raised;
  background: $subject-ink;
}

.cp__canvas {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
}

.cp__canvas:focus-visible {
  outline: 2px solid rgba(255, 255, 255, .85);
  outline-offset: -6px;
}

.cp__status {
  position: absolute;
  left: $sp-3;
  top: $sp-3;
  max-width: 62%;
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .85);
  color: $subject-ink;
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
  pointer-events: none;
}

.cp__btn {
  position: absolute;
  right: $sp-3;
  bottom: $sp-3;
  margin: 0;
  padding: $sp-1 $sp-3;
  border: 0;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .85);
  color: $subject-ink;
  font-family: inherit;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  cursor: pointer;
}

.cp__btn:focus-visible {
  outline: 2px solid #ffffff;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .cp__btn { font-size: 10px; padding: $sp-1 $sp-2; }
  .cp__status { font-size: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  .cp { cursor: default; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.cp {
  position: relative;
  width: min(92vw, 160vh - 12.8vw);
  aspect-ratio: 480/300;
  margin: 0 auto;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  background: #17141a;
}

.cp__canvas {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
}

.cp__canvas:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.85);
  outline-offset: -6px;
}

.cp__status {
  position: absolute;
  left: 12px;
  top: 12px;
  max-width: 62%;
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #17141a;
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
  pointer-events: none;
}

.cp__btn {
  position: absolute;
  right: 12px;
  bottom: 12px;
  margin: 0;
  padding: 4px 12px;
  border: 0;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #17141a;
  font-family: inherit;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  cursor: pointer;
}

.cp__btn:focus-visible {
  outline: 2px solid #ffffff;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .cp__btn {
    font-size: 10px;
    padding: 4px 8px;
  }
  .cp__status {
    font-size: 10px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cp {
    cursor: default;
  }
}

(function () {
    const root = document.getElementById("cp");
    if (!root)
        return;
    const W = 480;
    const H = 300;
    const PI2 = Math.PI * 2;
    const FIXED_DT = 16;
    const IDLE_TICKS = 150;
    const BTN_PAUSE = '一時停止';
    const BTN_PLAY = '再生';
    const BTN_NEXT = '次の場面';
    // 파스텔 팔레트 - 어두운 판 위에 밝은 색을 얹어 명도 차로 읽힌다
    const BG = [29, 26, 44];
    const PANEL = [44, 40, 68];
    const MINT = [126, 226, 192];
    const SKY = [124, 196, 255];
    const LILAC = [190, 164, 255];
    const PINK = [255, 160, 190];
    const PEACH = [255, 208, 168];
    const CREAM = [255, 244, 224];
    const CHARSET = 'ABCDEFGHJKLMNPQRSTUVWXYZabdefghmnqrt23456789';
    function clamp(v, lo, hi) { return v < lo ? lo : (v > hi ? hi : v); }
    function lerp(a, b, k) { return a + (b - a) * k; }
    function smooth(x) { const c = clamp(x, 0, 1); return c * c * (3 - 2 * c); }
    function easeOutBack(x) { const c = clamp(x, 0, 1) - 1; return 1 + c * c * (2.7 * c + 1.7); }
    function rgba(c, a) {
        return 'rgba(' + Math.round(c[0]) + ',' + Math.round(c[1]) + ',' + Math.round(c[2]) + ',' + clamp(a, 0, 1).toFixed(3) + ')';
    }
    function mix(a, b, k) {
        return [lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)];
    }
    // 시드 고정 난수 - 같은 시드면 언제나 같은 수열 (선형 합동 방식)
    function lcg(seed) {
        let s = seed >>> 0;
        return function () {
            s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
            return s / 4294967296;
        };
    }
    // 정수 두 개와 시드로 0 이상 1 미만의 값을 만드는 해시 (같은 입력은 늘 같은 값)
    function hash2(x, y, seed) {
        let h = (Math.imul(x | 0, 374761393) + Math.imul(y | 0, 668265263) + Math.imul(seed | 0, 1442695041)) | 0;
        h = Math.imul(h ^ (h >>> 13), 1274126177);
        h ^= h >>> 16;
        return (h >>> 0) / 4294967296;
    }
    // 시드로 뜻 없는 글자열을 만든다
    function glyphStr(seed, n) {
        const r = lcg(seed * 7919 + 13);
        let s = '';
        for (let i = 0; i < n; i += 1) {
            s += CHARSET.charAt(Math.floor(r() * CHARSET.length));
        }
        return s;
    }
    function rrect(ctx, x, y, w, h, r) {
        const rr = Math.max(0, Math.min(r, w / 2, h / 2));
        ctx.beginPath();
        ctx.moveTo(x + rr, y);
        ctx.lineTo(x + w - rr, y);
        ctx.arcTo(x + w, y, x + w, y + rr, rr);
        ctx.lineTo(x + w, y + h - rr);
        ctx.arcTo(x + w, y + h, x + w - rr, y + h, rr);
        ctx.lineTo(x + rr, y + h);
        ctx.arcTo(x, y + h, x, y + h - rr, rr);
        ctx.lineTo(x, y + rr);
        ctx.arcTo(x, y, x + rr, y, rr);
        ctx.closePath();
    }
    function mount(root, make) {
        const canvas = root.querySelector('[data-role="canvas"]');
        const statusEl = root.querySelector('[data-role="status"]');
        const btnEl = root.querySelector('[data-role="btn"]');
        if (!canvas || !statusEl || !btnEl) {
            return function () { return; };
        }
        const ctx = canvas.getContext('2d');
        if (!ctx) {
            return function () { return; };
        }
        const dpr = Math.min(window.devicePixelRatio || 1, 2);
        canvas.width = Math.round(W * dpr);
        canvas.height = Math.round(H * dpr);
        ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
        const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
        const inp = { idle: 99999, focus: false, key: false };
        const scene = make(inp, reduce);
        let paused = false;
        let rafId = 0;
        let lastTs = -1;
        let accMs = 0;
        let lastLabel = '';
        let lastLabelTick = -999;
        let lastLive = 'polite';
        let tickN = 0;
        let clk = 0;
        let wasAuto = true;
        const cleaners = [];
        function listen(target, type, fn) {
            target.addEventListener(type, fn);
            cleaners.push(function () { target.removeEventListener(type, fn); });
        }
        function show() {
            scene.draw(ctx);
            // 시연이 혼자 돌 때는 낭독을 끄고, 사람이 만지는 동안은 값이 바뀌어도 0.7초에 한 번만 갱신한다
            const live = (reduce || inp.idle <= IDLE_TICKS) ? 'polite' : 'off';
            if (live !== lastLive) {
                lastLive = live;
                statusEl.setAttribute('aria-live', live);
            }
            const t = scene.label();
            if (t !== lastLabel && (reduce || live === 'off' || tickN - lastLabelTick >= 44)) {
                lastLabel = t;
                lastLabelTick = tickN;
                statusEl.textContent = t;
            }
        }
        // 고정 간격 한 틱 - 입력이 없으면 시연 스크립트가 같은 입구로 입력을 대신 넣는다
        function advance() {
            inp.idle += 1;
            tickN += 1;
            const a = inp.idle > IDLE_TICKS;
            if (a && !wasAuto) {
                scene.reset();
                clk = 0;
            }
            wasAuto = a;
            if (a) {
                clk += 1;
                scene.auto(clk);
                if (clk >= scene.CYCLE) {
                    clk = 0;
                    scene.reset();
                }
            }
            scene.step();
        }
        // 움직임 줄이기: 틱을 몰아서 돌린 뒤 한 번만 그린다 (중간 보간 장면은 화면에 나오지 않는다)
        function settle(n) {
            for (let i = 0; i < n; i += 1) {
                inp.idle = 0;
                tickN += 1;
                scene.step();
            }
            show();
        }
        function tick(ts) {
            if (lastTs < 0) {
                lastTs = ts;
            }
            const frameDt = Math.min(ts - lastTs, 160);
            lastTs = ts;
            if (!paused) {
                accMs += frameDt;
                while (accMs >= FIXED_DT) {
                    advance();
                    accMs -= FIXED_DT;
                }
                show();
            }
            rafId = requestAnimationFrame(tick);
        }
        function point(e) {
            const r = canvas.getBoundingClientRect();
            return [clamp((e.clientX - r.left) * W / r.width, 0, W), clamp((e.clientY - r.top) * H / r.height, 0, H)];
        }
        btnEl.textContent = reduce ? BTN_NEXT : BTN_PAUSE;
        if (reduce) {
            root.classList.remove('is-demo');
            for (let i = 0; i < scene.REDUCE_TICKS; i += 1) {
                advance();
            }
            show();
        }
        listen(btnEl, 'click', function () {
            if (reduce) {
                if (scene.next) {
                    scene.next();
                    show();
                    return;
                }
                const n = Math.round(scene.CYCLE / 3);
                inp.idle = 99999;
                wasAuto = true;
                for (let i = 0; i < n; i += 1) {
                    advance();
                }
                show();
                return;
            }
            paused = !paused;
            if (paused) {
                root.classList.remove('is-demo');
            }
            else {
                root.classList.add('is-demo');
            }
            btnEl.textContent = paused ? BTN_PLAY : BTN_PAUSE;
        });
        listen(canvas, 'focus', function () { inp.focus = true; if (reduce) {
            show();
        } });
        listen(canvas, 'blur', function () { inp.focus = false; inp.key = false; if (reduce) {
            show();
        } });
        listen(canvas, 'pointerdown', function (e) {
            const p = point(e);
            inp.idle = 0;
            inp.key = false;
            try {
                canvas.setPointerCapture(e.pointerId);
            }
            catch (err) { /* 캡처가 안 되는 환경은 그냥 넘어간다 */ }
            scene.down(p[0], p[1]);
            if (reduce) {
                settle(30);
            }
        });
        listen(canvas, 'pointermove', function (e) {
            const p = point(e);
            inp.idle = 0;
            inp.key = false;
            scene.move(p[0], p[1]);
            if (reduce) {
                settle(30);
            }
        });
        listen(canvas, 'pointerup', function (e) {
            const p = point(e);
            inp.idle = 0;
            scene.up(p[0], p[1]);
            if (reduce) {
                settle(30);
            }
        });
        listen(canvas, 'keydown', function (e) {
            inp.idle = 0;
            inp.key = true;
            if (scene.key(e.key)) {
                e.preventDefault();
            }
            if (reduce) {
                settle(30);
            }
        });
        if (!reduce) {
            rafId = requestAnimationFrame(tick);
        }
        return function () {
            cancelAnimationFrame(rafId);
            for (let i = 0; i < cleaners.length; i += 1) {
                cleaners[i]();
            }
        };
    }
    const TTL_MS = 1300; // 새 글자판이 유효한 시간 (시연 길이에 맞춘 값 - 쓸 때는 늘려 쓴다)
    const WARN_FRAC = 0.3; // 남은 비율이 이 밑으로 내려가면 경고색
    const REFRESH_SPIN_MS = 360; // 새로고침 아이콘이 반 바퀴 도는 시간
    const RING_W = 12; // 고리 두께 (px)
    const RX = 384;
    const RY = 150;
    const RR = 78;
    const TXT_LEFT = '更新 {n} 回 · 有効 {s} 秒';
    const TXT_WARN = 'まもなく期限切れ · 更新 {n} 回';
    const TXT_EXPIRED = '期限切れ · 更新中';
    const TXT_BOARD_OFF = '期限切れ';
    // PURE-BEGIN
    // 남은 시간 비율 - 고리 호의 길이가 된다
    function ringFrac(elapsedMs, ttlMs) {
        const f = 1 - elapsedMs / ttlMs;
        return f < 0 ? 0 : (f > 1 ? 1 : f);
    }
    // 경고 구간 안에서 0 에서 1 로 올라가는 색 섞음 비율
    function warnMix(frac, warn) {
        if (frac >= warn) {
            return 0;
        }
        const k = 1 - frac / warn;
        return k > 1 ? 1 : k;
    }
    // PURE-END
    const make = (inp, reduce) => {
        let seed = 31;
        let elapsed = 0;
        let spinT = -1;
        let refreshes = 0;
        let fillAnim = 1;
        let stage = 0;
        let t = 0;
        function startRefresh() {
            if (reduce) {
                seed += 1;
                refreshes += 1;
                elapsed = 0;
                return;
            }
            if (spinT < 0) {
                spinT = 0;
            }
        }
        function easeSpin(x) {
            const c = clamp(x, 0, 1);
            return c < 0.5 ? 4 * c * c * c : 1 - Math.pow(-2 * c + 2, 3) / 2;
        }
        const scene = {
            CYCLE: 1000,
            REDUCE_TICKS: 0,
            reset() { return; },
            auto() { return; },
            next() {
                stage = (stage + 1) % 3;
                if (stage === 0) {
                    elapsed = 0;
                }
                if (stage === 1) {
                    elapsed = TTL_MS * (1 - WARN_FRAC * 0.5);
                }
                if (stage === 2) {
                    seed += 1;
                    refreshes += 1;
                    elapsed = 0;
                    stage = 0;
                }
            },
            step() {
                t += 1;
                if (reduce) {
                    return;
                }
                if (spinT >= 0) {
                    spinT += FIXED_DT / REFRESH_SPIN_MS;
                    if (spinT >= 1) {
                        spinT = -1;
                        seed += 1;
                        refreshes += 1;
                        elapsed = 0;
                        fillAnim = 0;
                    }
                }
                else {
                    elapsed += FIXED_DT;
                    if (elapsed >= TTL_MS) {
                        elapsed = TTL_MS;
                        spinT = 0;
                    }
                }
                if (fillAnim < 1) {
                    fillAnim = Math.min(1, fillAnim + FIXED_DT / 220);
                }
            },
            draw(ctx) {
                ctx.fillStyle = rgba(BG, 1);
                ctx.fillRect(0, 0, W, H);
                const frac0 = ringFrac(elapsed, TTL_MS);
                const frac = spinT >= 0 ? 0 : Math.min(frac0, smooth(fillAnim));
                const wm = warnMix(frac0, WARN_FRAC);
                const expired = spinT >= 0;
                // 글자판
                ctx.fillStyle = rgba(PANEL, 1);
                rrect(ctx, 20, 62, 276, 176, 18);
                ctx.fill();
                const text = glyphStr(seed, 5);
                const r = lcg(seed * 29 + 3);
                ctx.save();
                ctx.globalAlpha = expired ? 0.28 : 1;
                ctx.font = 'bold 54px "Segoe UI", "Noto Sans KR", sans-serif';
                ctx.textAlign = 'center';
                ctx.textBaseline = 'middle';
                const cols = [MINT, SKY, PINK, PEACH, CREAM];
                for (let i = 0; i < 5; i += 1) {
                    ctx.save();
                    ctx.translate(58 + i * 47, 150 + (r() - 0.5) * 22 + Math.sin(t * 0.07 + i * 1.9) * 3);
                    ctx.rotate((r() - 0.5) * 0.5);
                    ctx.fillStyle = rgba(cols[(i + seed) % cols.length], 1);
                    ctx.fillText(text.charAt(i), 0, 0);
                    ctx.restore();
                }
                ctx.strokeStyle = rgba(CREAM, 0.7);
                ctx.lineWidth = 2;
                for (let i = 0; i < 3; i += 1) {
                    const y0 = 90 + r() * 120;
                    ctx.beginPath();
                    ctx.moveTo(30, y0);
                    ctx.bezierCurveTo(100, y0 - 40, 200, y0 + 40, 286, 90 + r() * 120);
                    ctx.stroke();
                }
                ctx.restore();
                if (expired) {
                    ctx.fillStyle = rgba(PINK, 1);
                    ctx.font = 'bold 26px "Segoe UI", "Noto Sans KR", sans-serif';
                    ctx.fillText(TXT_BOARD_OFF, 158, 150);
                }
                // 고리 - 호 길이가 남은 시간
                const col = mix(MINT, PINK, wm);
                ctx.lineCap = 'round';
                ctx.lineWidth = RING_W;
                ctx.strokeStyle = rgba(CREAM, 0.18);
                ctx.beginPath();
                ctx.arc(RX, RY, RR, 0, PI2);
                ctx.stroke();
                if (frac > 0.002) {
                    ctx.strokeStyle = rgba(col, 1);
                    ctx.beginPath();
                    ctx.arc(RX, RY, RR, -Math.PI / 2, -Math.PI / 2 + PI2 * frac);
                    ctx.stroke();
                    const ha = -Math.PI / 2 + PI2 * frac;
                    ctx.fillStyle = rgba(CREAM, 1);
                    ctx.beginPath();
                    ctx.arc(RX + Math.cos(ha) * RR, RY + Math.sin(ha) * RR, 5 + wm * Math.abs(Math.sin(t * 0.25)) * 2, 0, PI2);
                    ctx.fill();
                }
                // 새로고침 아이콘 - 만료되면 반 바퀴 돈다
                const ang = spinT >= 0 ? Math.PI * easeSpin(spinT) : 0;
                ctx.save();
                ctx.translate(RX, RY);
                ctx.rotate(ang);
                ctx.strokeStyle = rgba(spinT >= 0 ? PINK : CREAM, 1);
                ctx.lineWidth = 7;
                ctx.beginPath();
                ctx.arc(0, 0, 26, 0.35 * Math.PI, 1.75 * Math.PI);
                ctx.stroke();
                ctx.fillStyle = rgba(spinT >= 0 ? PINK : CREAM, 1);
                ctx.beginPath();
                ctx.moveTo(26 * Math.cos(1.75 * Math.PI) - 10, 26 * Math.sin(1.75 * Math.PI) - 12);
                ctx.lineTo(26 * Math.cos(1.75 * Math.PI) + 12, 26 * Math.sin(1.75 * Math.PI) - 2);
                ctx.lineTo(26 * Math.cos(1.75 * Math.PI) - 4, 26 * Math.sin(1.75 * Math.PI) + 12);
                ctx.closePath();
                ctx.fill();
                ctx.restore();
                if (inp.key && inp.focus) {
                    ctx.strokeStyle = 'rgba(255,255,255,0.95)';
                    ctx.lineWidth = 2.5;
                    ctx.beginPath();
                    ctx.arc(RX, RY, RR + 14, 0, PI2);
                    ctx.stroke();
                }
            },
            label() {
                if (spinT >= 0) {
                    return TXT_EXPIRED;
                }
                const ttl = String(Math.round(TTL_MS / 100) / 10);
                if (warnMix(ringFrac(elapsed, TTL_MS), WARN_FRAC) > 0) {
                    return TXT_WARN.replace('{n}', String(refreshes));
                }
                return TXT_LEFT.replace('{s}', ttl).replace('{n}', String(refreshes));
            },
            down(x, y) {
                if (Math.hypot(x - RX, y - RY) <= RR + 16) {
                    startRefresh();
                }
            },
            move() { return; },
            up() { return; },
            key(k) {
                if (k === 'Enter' || k === ' ' || k === 'r' || k === 'R') {
                    startRefresh();
                    return true;
                }
                return false;
            },
        };
        return scene;
    };
    return mount(root, make);
})();

// CapExpireRingRefreshSpin - vanilla 판(09-cap-expire-ring-refresh-spin) 의 React 포트. 같은 계산을 useEffect 안에서 돌린다.
import { useEffect, useRef } from "react";
import styles from "./CapExpireRingRefreshSpin.module.scss";

const cx = (s: string): string => s.split(" ").map((n) => styles[n] ?? n).join(" ");

export default function CapExpireRingRefreshSpin() {
  const rootRef = useRef<HTMLDivElement | null>(null);

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    type RGB = [number, number, number];
    interface Input { idle: number; focus: boolean; key: boolean; }
    interface Scene {
        CYCLE: number;
        REDUCE_TICKS: number;
        reset(): void;
        auto(clk: number): void;
        step(): void;
        draw(ctx: CanvasRenderingContext2D): void;
        label(): string;
        down(x: number, y: number): void;
        move(x: number, y: number): void;
        up(x: number, y: number): void;
        key(k: string): boolean;
        next?(): void;
    }
    type Make = (inp: Input, reduce: boolean) => Scene;
    const W = 480;
    const H = 300;
    const PI2 = Math.PI * 2;
    const FIXED_DT = 16;
    const IDLE_TICKS = 150;
    const BTN_PAUSE = '멈춤';
    const BTN_PLAY = '재생';
    const BTN_NEXT = '다음 장면';
    // 파스텔 팔레트 - 어두운 판 위에 밝은 색을 얹어 명도 차로 읽힌다
    const BG: RGB = [29, 26, 44];
    const PANEL: RGB = [44, 40, 68];
    const MINT: RGB = [126, 226, 192];
    const SKY: RGB = [124, 196, 255];
    const LILAC: RGB = [190, 164, 255];
    const PINK: RGB = [255, 160, 190];
    const PEACH: RGB = [255, 208, 168];
    const CREAM: RGB = [255, 244, 224];
    const CHARSET = 'ABCDEFGHJKLMNPQRSTUVWXYZabdefghmnqrt23456789';
    function clamp(v: number, lo: number, hi: number): number { return v < lo ? lo : (v > hi ? hi : v); }
    function lerp(a: number, b: number, k: number): number { return a + (b - a) * k; }
    function smooth(x: number): number { const c = clamp(x, 0, 1); return c * c * (3 - 2 * c); }
    function easeOutBack(x: number): number { const c = clamp(x, 0, 1) - 1; return 1 + c * c * (2.7 * c + 1.7); }
    function rgba(c: RGB, a: number): string {
        return 'rgba(' + Math.round(c[0]) + ',' + Math.round(c[1]) + ',' + Math.round(c[2]) + ',' + clamp(a, 0, 1).toFixed(3) + ')';
    }
    function mix(a: RGB, b: RGB, k: number): RGB {
        return [lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)];
    }
    // 시드 고정 난수 - 같은 시드면 언제나 같은 수열 (선형 합동 방식)
    function lcg(seed: number): () => number {
        let s = seed >>> 0;
        return function () {
            s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
            return s / 4294967296;
        };
    }
    // 정수 두 개와 시드로 0 이상 1 미만의 값을 만드는 해시 (같은 입력은 늘 같은 값)
    function hash2(x: number, y: number, seed: number): number {
        let h = (Math.imul(x | 0, 374761393) + Math.imul(y | 0, 668265263) + Math.imul(seed | 0, 1442695041)) | 0;
        h = Math.imul(h ^ (h >>> 13), 1274126177);
        h ^= h >>> 16;
        return (h >>> 0) / 4294967296;
    }
    // 시드로 뜻 없는 글자열을 만든다
    function glyphStr(seed: number, n: number): string {
        const r = lcg(seed * 7919 + 13);
        let s = '';
        for (let i = 0; i < n; i += 1) {
            s += CHARSET.charAt(Math.floor(r() * CHARSET.length));
        }
        return s;
    }
    function rrect(ctx: CanvasRenderingContext2D, x: number, y: number, w: number, h: number, r: number): void {
        const rr = Math.max(0, Math.min(r, w / 2, h / 2));
        ctx.beginPath();
        ctx.moveTo(x + rr, y);
        ctx.lineTo(x + w - rr, y);
        ctx.arcTo(x + w, y, x + w, y + rr, rr);
        ctx.lineTo(x + w, y + h - rr);
        ctx.arcTo(x + w, y + h, x + w - rr, y + h, rr);
        ctx.lineTo(x + rr, y + h);
        ctx.arcTo(x, y + h, x, y + h - rr, rr);
        ctx.lineTo(x, y + rr);
        ctx.arcTo(x, y, x + rr, y, rr);
        ctx.closePath();
    }
    function mount(root: HTMLElement, make: Make): () => void {
        const canvas = root.querySelector('[data-role="canvas"]') as HTMLCanvasElement;
        const statusEl = root.querySelector('[data-role="status"]') as HTMLElement;
        const btnEl = root.querySelector('[data-role="btn"]') as HTMLButtonElement;
        if (!canvas || !statusEl || !btnEl) {
            return function () { return; };
        }
        const ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
        if (!ctx) {
            return function () { return; };
        }
        const dpr = Math.min(window.devicePixelRatio || 1, 2);
        canvas.width = Math.round(W * dpr);
        canvas.height = Math.round(H * dpr);
        ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
        const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
        const inp: Input = { idle: 99999, focus: false, key: false };
        const scene = make(inp, reduce);
        let paused = false;
        let rafId = 0;
        let lastTs = -1;
        let accMs = 0;
        let lastLabel = '';
        let lastLabelTick = -999;
        let lastLive = 'polite';
        let tickN = 0;
        let clk = 0;
        let wasAuto = true;
        const cleaners: Array<() => void> = [];
        function listen<K extends keyof HTMLElementEventMap>(target: HTMLElement, type: K, fn: (e: HTMLElementEventMap[K]) => void): void {
            target.addEventListener(type, fn);
            cleaners.push(function () { target.removeEventListener(type, fn); });
        }
        function show(): void {
            scene.draw(ctx);
            // 시연이 혼자 돌 때는 낭독을 끄고, 사람이 만지는 동안은 값이 바뀌어도 0.7초에 한 번만 갱신한다
            const live = (reduce || inp.idle <= IDLE_TICKS) ? 'polite' : 'off';
            if (live !== lastLive) {
                lastLive = live;
                statusEl.setAttribute('aria-live', live);
            }
            const t = scene.label();
            if (t !== lastLabel && (reduce || live === 'off' || tickN - lastLabelTick >= 44)) {
                lastLabel = t;
                lastLabelTick = tickN;
                statusEl.textContent = t;
            }
        }
        // 고정 간격 한 틱 - 입력이 없으면 시연 스크립트가 같은 입구로 입력을 대신 넣는다
        function advance(): void {
            inp.idle += 1;
            tickN += 1;
            const a = inp.idle > IDLE_TICKS;
            if (a && !wasAuto) {
                scene.reset();
                clk = 0;
            }
            wasAuto = a;
            if (a) {
                clk += 1;
                scene.auto(clk);
                if (clk >= scene.CYCLE) {
                    clk = 0;
                    scene.reset();
                }
            }
            scene.step();
        }
        // 움직임 줄이기: 틱을 몰아서 돌린 뒤 한 번만 그린다 (중간 보간 장면은 화면에 나오지 않는다)
        function settle(n: number): void {
            for (let i = 0; i < n; i += 1) {
                inp.idle = 0;
                tickN += 1;
                scene.step();
            }
            show();
        }
        function tick(ts: number): void {
            if (lastTs < 0) {
                lastTs = ts;
            }
            const frameDt = Math.min(ts - lastTs, 160);
            lastTs = ts;
            if (!paused) {
                accMs += frameDt;
                while (accMs >= FIXED_DT) {
                    advance();
                    accMs -= FIXED_DT;
                }
                show();
            }
            rafId = requestAnimationFrame(tick);
        }
        function point(e: PointerEvent): number[] {
            const r = canvas.getBoundingClientRect();
            return [clamp((e.clientX - r.left) * W / r.width, 0, W), clamp((e.clientY - r.top) * H / r.height, 0, H)];
        }
        btnEl.textContent = reduce ? BTN_NEXT : BTN_PAUSE;
        if (reduce) {
            root.classList.remove('is-demo');
            for (let i = 0; i < scene.REDUCE_TICKS; i += 1) {
                advance();
            }
            show();
        }
        listen(btnEl, 'click', function () {
            if (reduce) {
                if (scene.next) {
                    scene.next();
                    show();
                    return;
                }
                const n = Math.round(scene.CYCLE / 3);
                inp.idle = 99999;
                wasAuto = true;
                for (let i = 0; i < n; i += 1) {
                    advance();
                }
                show();
                return;
            }
            paused = !paused;
            if (paused) {
                root.classList.remove('is-demo');
            }
            else {
                root.classList.add('is-demo');
            }
            btnEl.textContent = paused ? BTN_PLAY : BTN_PAUSE;
        });
        listen(canvas, 'focus', function () { inp.focus = true; if (reduce) { show(); } });
        listen(canvas, 'blur', function () { inp.focus = false; inp.key = false; if (reduce) { show(); } });
        listen(canvas, 'pointerdown', function (e) {
            const p = point(e);
            inp.idle = 0;
            inp.key = false;
            try { canvas.setPointerCapture(e.pointerId); } catch (err) { /* 캡처가 안 되는 환경은 그냥 넘어간다 */ }
            scene.down(p[0], p[1]);
            if (reduce) { settle(30); }
        });
        listen(canvas, 'pointermove', function (e) {
            const p = point(e);
            inp.idle = 0;
            inp.key = false;
            scene.move(p[0], p[1]);
            if (reduce) { settle(30); }
        });
        listen(canvas, 'pointerup', function (e) {
            const p = point(e);
            inp.idle = 0;
            scene.up(p[0], p[1]);
            if (reduce) { settle(30); }
        });
        listen(canvas, 'keydown', function (e) {
            inp.idle = 0;
            inp.key = true;
            if (scene.key(e.key)) {
                e.preventDefault();
            }
            if (reduce) { settle(30); }
        });
        if (!reduce) {
            rafId = requestAnimationFrame(tick);
        }
        return function () {
            cancelAnimationFrame(rafId);
            for (let i = 0; i < cleaners.length; i += 1) {
                cleaners[i]();
            }
        };
    }
    const TTL_MS = 1300;          // 새 글자판이 유효한 시간 (시연 길이에 맞춘 값 - 쓸 때는 늘려 쓴다)
    const WARN_FRAC = 0.3;        // 남은 비율이 이 밑으로 내려가면 경고색
    const REFRESH_SPIN_MS = 360;  // 새로고침 아이콘이 반 바퀴 도는 시간
    const RING_W = 12;            // 고리 두께 (px)
    const RX = 384;
    const RY = 150;
    const RR = 78;
    const TXT_LEFT = '새로고침 {n}회 · 유효 시간 {s}초';
    const TXT_WARN = '곧 만료 · 새로고침 {n}회';
    const TXT_EXPIRED = '만료 · 새로고침 중';
    const TXT_BOARD_OFF = '만료';
    // PURE-BEGIN
    // 남은 시간 비율 - 고리 호의 길이가 된다
    function ringFrac(elapsedMs: number, ttlMs: number): number {
        const f = 1 - elapsedMs / ttlMs;
        return f < 0 ? 0 : (f > 1 ? 1 : f);
    }
    // 경고 구간 안에서 0 에서 1 로 올라가는 색 섞음 비율
    function warnMix(frac: number, warn: number): number {
        if (frac >= warn) { return 0; }
        const k = 1 - frac / warn;
        return k > 1 ? 1 : k;
    }
    // PURE-END
    const make: Make = (inp, reduce) => {
        let seed = 31;
        let elapsed = 0;
        let spinT = -1;
        let refreshes = 0;
        let fillAnim = 1;
        let stage = 0;
        let t = 0;
        function startRefresh(): void {
            if (reduce) {
                seed += 1;
                refreshes += 1;
                elapsed = 0;
                return;
            }
            if (spinT < 0) { spinT = 0; }
        }
        function easeSpin(x: number): number {
            const c = clamp(x, 0, 1);
            return c < 0.5 ? 4 * c * c * c : 1 - Math.pow(-2 * c + 2, 3) / 2;
        }
        const scene: Scene = {
            CYCLE: 1000,
            REDUCE_TICKS: 0,
            reset() { return; },
            auto() { return; },
            next() {
                stage = (stage + 1) % 3;
                if (stage === 0) { elapsed = 0; }
                if (stage === 1) { elapsed = TTL_MS * (1 - WARN_FRAC * 0.5); }
                if (stage === 2) { seed += 1; refreshes += 1; elapsed = 0; stage = 0; }
            },
            step() {
                t += 1;
                if (reduce) { return; }
                if (spinT >= 0) {
                    spinT += FIXED_DT / REFRESH_SPIN_MS;
                    if (spinT >= 1) {
                        spinT = -1;
                        seed += 1;
                        refreshes += 1;
                        elapsed = 0;
                        fillAnim = 0;
                    }
                }
                else {
                    elapsed += FIXED_DT;
                    if (elapsed >= TTL_MS) { elapsed = TTL_MS; spinT = 0; }
                }
                if (fillAnim < 1) { fillAnim = Math.min(1, fillAnim + FIXED_DT / 220); }
            },
            draw(ctx) {
                ctx.fillStyle = rgba(BG, 1);
                ctx.fillRect(0, 0, W, H);
                const frac0 = ringFrac(elapsed, TTL_MS);
                const frac = spinT >= 0 ? 0 : Math.min(frac0, smooth(fillAnim));
                const wm = warnMix(frac0, WARN_FRAC);
                const expired = spinT >= 0;
                // 글자판
                ctx.fillStyle = rgba(PANEL, 1);
                rrect(ctx, 20, 62, 276, 176, 18);
                ctx.fill();
                const text = glyphStr(seed, 5);
                const r = lcg(seed * 29 + 3);
                ctx.save();
                ctx.globalAlpha = expired ? 0.28 : 1;
                ctx.font = 'bold 54px "Segoe UI", "Noto Sans KR", sans-serif';
                ctx.textAlign = 'center';
                ctx.textBaseline = 'middle';
                const cols = [MINT, SKY, PINK, PEACH, CREAM];
                for (let i = 0; i < 5; i += 1) {
                    ctx.save();
                    ctx.translate(58 + i * 47, 150 + (r() - 0.5) * 22 + Math.sin(t * 0.07 + i * 1.9) * 3);
                    ctx.rotate((r() - 0.5) * 0.5);
                    ctx.fillStyle = rgba(cols[(i + seed) % cols.length], 1);
                    ctx.fillText(text.charAt(i), 0, 0);
                    ctx.restore();
                }
                ctx.strokeStyle = rgba(CREAM, 0.7);
                ctx.lineWidth = 2;
                for (let i = 0; i < 3; i += 1) {
                    const y0 = 90 + r() * 120;
                    ctx.beginPath();
                    ctx.moveTo(30, y0);
                    ctx.bezierCurveTo(100, y0 - 40, 200, y0 + 40, 286, 90 + r() * 120);
                    ctx.stroke();
                }
                ctx.restore();
                if (expired) {
                    ctx.fillStyle = rgba(PINK, 1);
                    ctx.font = 'bold 26px "Segoe UI", "Noto Sans KR", sans-serif';
                    ctx.fillText(TXT_BOARD_OFF, 158, 150);
                }
                // 고리 - 호 길이가 남은 시간
                const col = mix(MINT, PINK, wm);
                ctx.lineCap = 'round';
                ctx.lineWidth = RING_W;
                ctx.strokeStyle = rgba(CREAM, 0.18);
                ctx.beginPath();
                ctx.arc(RX, RY, RR, 0, PI2);
                ctx.stroke();
                if (frac > 0.002) {
                    ctx.strokeStyle = rgba(col, 1);
                    ctx.beginPath();
                    ctx.arc(RX, RY, RR, -Math.PI / 2, -Math.PI / 2 + PI2 * frac);
                    ctx.stroke();
                    const ha = -Math.PI / 2 + PI2 * frac;
                    ctx.fillStyle = rgba(CREAM, 1);
                    ctx.beginPath();
                    ctx.arc(RX + Math.cos(ha) * RR, RY + Math.sin(ha) * RR, 5 + wm * Math.abs(Math.sin(t * 0.25)) * 2, 0, PI2);
                    ctx.fill();
                }
                // 새로고침 아이콘 - 만료되면 반 바퀴 돈다
                const ang = spinT >= 0 ? Math.PI * easeSpin(spinT) : 0;
                ctx.save();
                ctx.translate(RX, RY);
                ctx.rotate(ang);
                ctx.strokeStyle = rgba(spinT >= 0 ? PINK : CREAM, 1);
                ctx.lineWidth = 7;
                ctx.beginPath();
                ctx.arc(0, 0, 26, 0.35 * Math.PI, 1.75 * Math.PI);
                ctx.stroke();
                ctx.fillStyle = rgba(spinT >= 0 ? PINK : CREAM, 1);
                ctx.beginPath();
                ctx.moveTo(26 * Math.cos(1.75 * Math.PI) - 10, 26 * Math.sin(1.75 * Math.PI) - 12);
                ctx.lineTo(26 * Math.cos(1.75 * Math.PI) + 12, 26 * Math.sin(1.75 * Math.PI) - 2);
                ctx.lineTo(26 * Math.cos(1.75 * Math.PI) - 4, 26 * Math.sin(1.75 * Math.PI) + 12);
                ctx.closePath();
                ctx.fill();
                ctx.restore();
                if (inp.key && inp.focus) {
                    ctx.strokeStyle = 'rgba(255,255,255,0.95)';
                    ctx.lineWidth = 2.5;
                    ctx.beginPath();
                    ctx.arc(RX, RY, RR + 14, 0, PI2);
                    ctx.stroke();
                }
            },
            label() {
                if (spinT >= 0) { return TXT_EXPIRED; }
                const ttl = String(Math.round(TTL_MS / 100) / 10);
                if (warnMix(ringFrac(elapsed, TTL_MS), WARN_FRAC) > 0) { return TXT_WARN.replace('{n}', String(refreshes)); }
                return TXT_LEFT.replace('{s}', ttl).replace('{n}', String(refreshes));
            },
            down(x, y) {
                if (Math.hypot(x - RX, y - RY) <= RR + 16) { startRefresh(); }
            },
            move() { return; },
            up() { return; },
            key(k) {
                if (k === 'Enter' || k === ' ' || k === 'r' || k === 'R') { startRefresh(); return true; }
                return false;
            },
        };
        return scene;
    };

    return mount(root, make);
  }, []);

  return (
      <div className={cx("cp") + " is-demo"} id="cp" ref={rootRef}>
      <canvas className={cx("cp__canvas")} data-role="canvas" width="480" height="300" tabIndex={0} aria-label="문제 유효 시간이 고리로 줄다가 끝나면 새로고침 아이콘이 돌며 새 문제로 바뀌는 확인"></canvas>
      <p className={cx("cp__status")} data-role="status" aria-live="polite">시연 준비 중</p>
      <button className={cx("cp__btn")} data-role="btn" type="button">멈춤</button>
      </div>
  );
}