02フロンティアが波紋の形で外へ広がり育つ迷路

<main class="stage">
<div class="hs is-demo" id="hs">
  <canvas class="hs__canvas" data-role="canvas" width="480" height="300" tabindex="0" aria-label="掘った領域に接するマスの列からひとつずつ選んでつなぎ、編入の順番が波紋の帯として残る迷路。マスを押すとそこから育て直します"></canvas>
  <p class="hs__status" data-role="status" aria-live="off">フロンティアから一マスずつ選んでつないでいます</p>
  <div class="hs__tools">
    <button class="hs__btn" data-role="restart" type="button">育て直す</button>
    <button class="hs__btn" data-role="mode" type="button">選び方を変える</button>
  </div>
</div>
</main>

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

.hs {
  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;
}

.hs__canvas {
  display: block;
  width: 100%;
  height: 100%;
  cursor: crosshair;
}

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

.hs__status {
  position: absolute;
  left: $sp-3;
  bottom: $sp-3;
  box-sizing: border-box;
  max-width: 34%;
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-control;
  background: rgba(255, 255, 255, .85);
  color: $subject-ink;
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
  pointer-events: none;
}

// 판은 오른쪽에 있다 — 버튼은 왼쪽 위 칸에 두고, 좁으면 줄을 바꿔 판을 덮지 않는다
.hs__tools {
  position: absolute;
  left: $sp-3;
  top: $sp-3;
  box-sizing: border-box;
  max-width: 34%;
  display: flex;
  flex-wrap: wrap;
  gap: $sp-2;
}

.hs__btn {
  margin: 0;
  padding: $sp-1 $sp-3;
  border: 0;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .85);
  color: $subject-ink;
  font: inherit;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  cursor: pointer;
  transition: background-color $dur-quick ease-out;
}

.hs__btn:hover {
  background: $subject-cream;
}

.hs__btn[aria-pressed="true"] {
  background: $subject-mint;
}

.hs__btn:focus-visible {
  outline: 2px solid rgba(255, 255, 255, .95);
  outline-offset: 2px;
}

// 손가락 가로 끌기는 이 캔버스가 받고, 세로 쓸기는 브라우저에 남겨 페이지 스크롤이 막히지 않게 한다
.hs__canvas { touch-action: pan-y; }

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

@media (prefers-reduced-motion: reduce) {
  .hs__btn { transition: none; }
}

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);
}

.hs {
  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;
}

.hs__canvas {
  display: block;
  width: 100%;
  height: 100%;
  cursor: crosshair;
}

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

.hs__status {
  position: absolute;
  left: 12px;
  bottom: 12px;
  box-sizing: border-box;
  max-width: 34%;
  margin: 0;
  padding: 4px 12px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.85);
  color: #17141a;
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
  pointer-events: none;
}

.hs__tools {
  position: absolute;
  left: 12px;
  top: 12px;
  box-sizing: border-box;
  max-width: 34%;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.hs__btn {
  margin: 0;
  padding: 4px 12px;
  border: 0;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #17141a;
  font: inherit;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  cursor: pointer;
  transition: background-color 220ms ease-out;
}

.hs__btn:hover {
  background: #fff7e6;
}

.hs__btn[aria-pressed=true] {
  background: #4cd4a6;
}

.hs__btn:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.95);
  outline-offset: 2px;
}

.hs__canvas {
  touch-action: pan-y;
}

@media (max-width: 340px) {
  .hs__btn {
    font-size: 10px;
    padding: 4px 8px;
  }
  .hs__status {
    font-size: 10px;
    padding: 4px 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .hs__btn {
    transition: none;
  }
}

(function () {
    const root = document.getElementById("hs");
    if (!root) return;
    const W = 480;
    const H = 300;
    const FIXED_DT = 16;
    // 파스텔 팔레트 — 어두운 무대 위에 밝은 바닥을 얹어 명도 차로 길이 읽힌다
    const BG = [29, 26, 44];
    const ROCK = [44, 39, 64];
    const PAPER = [255, 248, 234];
    const INK = [58, 48, 76];
    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];
    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 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)]; }
    const canvasEl = root.querySelector('[data-role="canvas"]');
    const statusEl = root.querySelector('[data-role="status"]');
    const ctxRaw = canvasEl ? canvasEl.getContext('2d') : null;
    if (!canvasEl || !ctxRaw || !statusEl) {
        return;
    }
    const cv = canvasEl;
    const ctx = ctxRaw;
    const status = statusEl;
    const reduceQuery = window.matchMedia('(prefers-reduced-motion: reduce)');
    const still = reduceQuery.matches;
    // 자동 시연 중인가 — 사람이 처음 만지는 순간 시연을 멈추고 상태 줄을 읽어 주기 시작한다
    let demo = root.classList.contains('is-demo');
    function wake() {
        if (!demo) {
            return;
        }
        demo = false;
        root.classList.remove('is-demo');
        status.setAttribute('aria-live', 'polite');
    }
    function say(text) {
        if (status.textContent !== text) {
            status.textContent = text;
        }
    }
    function fitCanvas() {
        // 배율은 2 에서 자른다 — 배율 3 기기에서 화소가 2.25배로 늘어 프레임마다 일이 그만큼 커지지 않게
        const dpr = Math.min(window.devicePixelRatio || 1, 2);
        cv.width = Math.round(W * dpr);
        cv.height = Math.round(H * dpr);
        ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
    }
    function onResize() {
        fitCanvas();
        draw();
    }
    fitCanvas();
    window.addEventListener('resize', onResize);
    // 화면 좌표(CSS px) → 장면 좌표(480x300). 리사이즈 뒤에도 늘 현재 크기로 다시 잰다
    function toScene(ev) {
        const r = cv.getBoundingClientRect();
        return [((ev.clientX - r.left) / r.width) * W, ((ev.clientY - r.top) / r.height) * H];
    }
    // 시드 고정 난수 — 같은 시드면 같은 미로가 다시 나온다 (32비트 정수 섞기)
    function makeRng(seed) {
        let s = seed >>> 0;
        return function () {
            s = (s + 0x6d2b79f5) >>> 0;
            let t = s;
            t = Math.imul(t ^ (t >>> 15), t | 1);
            t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
            return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
        };
    }
    // 격자 — 31×31 칸, 칸마다 벽 네 장을 비트 하나씩으로 든다
    const GRID_N = 31;
    const CELL_N = GRID_N * GRID_N;
    const CS = 9;
    const BOARD = GRID_N * CS;
    let BX = W - 12 - BOARD;
    const BY = (H - BOARD) / 2;
    const ENTRY = 0;
    const EXIT = CELL_N - 1;
    // 방향 0 북 · 1 동 · 2 남 · 3 서 — 시계 방향 순서라 +1 이 오른쪽으로 돌기, +3 이 왼쪽으로 돌기
    const DX = [0, 1, 0, -1];
    const DY = [-1, 0, 1, 0];
    const BIT = [1, 2, 4, 8];
    const ALL_WALLS = 15;
    function neighbor(i, d) {
        const x = (i % GRID_N) + DX[d];
        const y = Math.floor(i / GRID_N) + DY[d];
        return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
    }
    function isOpen(walls, i, d) {
        return (walls[i] & BIT[d]) === 0 && neighbor(i, d) >= 0;
    }
    // 벽 한 장 걷기 — 양쪽 칸의 비트를 함께 지운다 (한쪽만 지우면 길이 일방통행이 된다)
    function knock(walls, i, d) {
        const n = neighbor(i, d);
        walls[i] &= ~BIT[d];
        walls[n] &= ~BIT[(d + 2) % 4];
        return n;
    }
    function openCount(walls, i) {
        let c = 0;
        for (let d = 0; d < 4; d += 1) {
            if (isOpen(walls, i, d)) {
                c += 1;
            }
        }
        return c;
    }
    function cellX(i) { return BX + (i % GRID_N) * CS; }
    function cellY(i) { return BY + Math.floor(i / GRID_N) * CS; }
    function cellAt(sx, sy) {
        const x = Math.floor((sx - BX) / CS);
        const y = Math.floor((sy - BY) / CS);
        return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
    }
    function fillCell(i, c, a) {
        ctx.fillStyle = rgba(c, a);
        ctx.fillRect(cellX(i), cellY(i), CS, CS);
    }
    // 벽 비트를 선분으로 — 칸마다 동·남 벽만 긋고 맨 윗줄·맨 왼줄만 북·서 벽을 더 긋는다 (같은 벽을 두 번 긋지 않는다)
    function strokeWalls(walls, color, lw) {
        ctx.beginPath();
        for (let i = 0; i < CELL_N; i += 1) {
            const x = cellX(i);
            const y = cellY(i);
            const w = walls[i];
            if ((w & 2) !== 0) {
                ctx.moveTo(x + CS, y);
                ctx.lineTo(x + CS, y + CS);
            }
            if ((w & 4) !== 0) {
                ctx.moveTo(x, y + CS);
                ctx.lineTo(x + CS, y + CS);
            }
            if (i < GRID_N && (w & 1) !== 0) {
                ctx.moveTo(x, y);
                ctx.lineTo(x + CS, y);
            }
            if (i % GRID_N === 0 && (w & 8) !== 0) {
                ctx.moveTo(x, y);
                ctx.lineTo(x, y + CS);
            }
        }
        ctx.strokeStyle = color;
        ctx.lineWidth = lw;
        ctx.lineCap = 'square';
        ctx.stroke();
    }
    // 입구(왼쪽 위)·출구(오른쪽 아래) 표시 — 바깥 벽 밖에 작은 삼각형
    function drawGates() {
        ctx.fillStyle = rgba(MINT, 0.95);
        ctx.beginPath();
        ctx.moveTo(BX - 9, BY + 1);
        ctx.lineTo(BX - 2, BY + CS / 2);
        ctx.lineTo(BX - 9, BY + CS - 1);
        ctx.closePath();
        ctx.fill();
        ctx.fillStyle = rgba(PINK, 0.95);
        ctx.beginPath();
        ctx.moveTo(BX + BOARD + 2, BY + BOARD - CS + 1);
        ctx.lineTo(BX + BOARD + 9, BY + BOARD - CS / 2);
        ctx.lineTo(BX + BOARD + 2, BY + BOARD - 1);
        ctx.closePath();
        ctx.fill();
    }
    // 왼쪽 칸의 수치 — 이름표 한 줄 + 값 한 줄
    function panelRow(row, label, value) {
        const y = 104 + row * 34;
        ctx.textAlign = 'left';
        ctx.textBaseline = 'alphabetic';
        ctx.fillStyle = rgba(PAPER, 0.62);
        ctx.font = '500 11px sans-serif';
        ctx.fillText(label, 16, y);
        ctx.fillStyle = rgba(PAPER, 0.96);
        ctx.font = '700 15px sans-serif';
        ctx.fillText(value, 16, y + 18);
    }
    function clearStage() {
        ctx.fillStyle = rgba(BG, 1);
        ctx.fillRect(0, 0, W, H);
    }
    function addFront(g, c) {
        for (let d = 0; d < 4; d += 1) {
            const n = neighbor(c, d);
            if (n < 0 || g.inMaze[n] === 1 || g.inFront[n] === 1) {
                continue;
            }
            g.inFront[n] = 1;
            g.front.push(n);
        }
    }
    function growStart(seed, start) {
        const g = { walls: new Uint8Array(CELL_N).fill(ALL_WALLS), inMaze: new Uint8Array(CELL_N), inFront: new Uint8Array(CELL_N), front: [], order: new Int32Array(CELL_N).fill(-1), count: 0, last: start, rnd: makeRng(seed) };
        g.inMaze[start] = 1;
        g.order[start] = 0;
        g.count = 1;
        addFront(g, start);
        return g;
    }
    // フロンティア(판 영역에 닿은 안 掘ったマス)에서 하나를 골라 이미 판 이웃 하나와 벽 한 장으로 잇는다
    function growOne(g, mode) {
        const len = g.front.length;
        if (len === 0) {
            return -1;
        }
        let c = 0;
        if (mode === 'newest') {
            c = g.front.pop();
        }
        else if (mode === 'oldest') {
            c = g.front.shift();
        }
        else {
            const k = Math.floor(g.rnd() * len);
            c = g.front[k];
            g.front[k] = g.front[len - 1];
            g.front.pop();
        }
        g.inFront[c] = 0;
        const links = [];
        for (let d = 0; d < 4; d += 1) {
            const n = neighbor(c, d);
            if (n >= 0 && g.inMaze[n] === 1) {
                links.push(d);
            }
        }
        knock(g.walls, c, links[Math.floor(g.rnd() * links.length)]);
        g.inMaze[c] = 1;
        g.order[c] = g.count;
        g.count += 1;
        g.last = c;
        addFront(g, c);
        return c;
    }
    function growAll(seed, start, mode) {
        const g = growStart(seed, start);
        while (growOne(g, mode) >= 0) { /* 프론티어가 빌 때까지 */ }
        return g.walls;
    }
    // 프론티어에서 다음 칸을 選び方 — random 은 아무거나, newest 는 막 들어온 것, oldest 는 가장 먼저 들어온 것
    const FRONTIER_PICK = 'random';
    // 편입 순번 몇 개마다 波紋の帯 하나를 두르나
    const RIPPLE_W = 26;
    // 띠가 생긴 뒤 칸이 하나 더 들어올 때마다 그 띠 색이 옅어지는 비율 (지수 감쇠)
    const RING_FADE = 0.0035;
    const GROW_MS = 8;
    const SEED = 464;
    const HOLD_MS = 1400;
    const CENTER = Math.floor(GRID_N / 2) * GRID_N + Math.floor(GRID_N / 2);
    const MODES = ['random', 'newest', 'oldest'];
    const TXT_GROW = 'フロンティアから一マスずつ選んでつないでいます';
    const TXT_DONE = '完成 — 壁を960枚払い、ひとつの盤になりました';
    const restartBtn = root.querySelector('[data-role="restart"]');
    const modeBtn = root.querySelector('[data-role="mode"]');
    let mode = FRONTIER_PICK;
    let pass = 0;
    let start = CENTER;
    let grower = growStart(SEED, start);
    let stepAcc = 0;
    let holdLeft = 0;
    function modeName(m) {
        return m === 'random' ? 'ランダム' : (m === 'newest' ? '最新のマス' : '最初のマス');
    }
    function done() { return grower.front.length === 0; }
    function report() { say(done() ? TXT_DONE : TXT_GROW); }
    function reset(s) {
        start = s;
        grower = growStart(SEED + pass, s);
        stepAcc = 0;
        holdLeft = 0;
    }
    function grow(n) {
        for (let k = 0; k < n && !done(); k += 1) {
            growOne(grower, mode);
        }
    }
    function step() {
        if (done()) {
            return;
        }
        stepAcc += FIXED_DT;
        while (stepAcc >= GROW_MS && !done()) {
            stepAcc -= GROW_MS;
            growOne(grower, mode);
        }
        report();
    }
    function settle() {
        grow(CELL_N);
        report();
    }
    function demoTick(t) {
        if (!done() || t < 0) {
            return;
        }
        holdLeft += FIXED_DT;
        if (holdLeft >= HOLD_MS) {
            pass += 1;
            reset(CENTER);
        }
    }
    const BAND_A = SKY;
    const BAND_B = LILAC;
    const OLD_PALE = mix(PAPER, BG, 0.05);
    function draw() {
        clearStage();
        ctx.fillStyle = rgba(ROCK, 1);
        ctx.fillRect(BX, BY, BOARD, BOARD);
        const g = grower;
        for (let i = 0; i < CELL_N; i += 1) {
            if (g.inMaze[i] === 1) {
                const o = g.order[i];
                const band = Math.floor(o / RIPPLE_W) % 2 === 0 ? BAND_A : BAND_B;
                const k = Math.exp(-(g.count - o) * RING_FADE);
                fillCell(i, mix(OLD_PALE, band, 0.22 + 0.78 * k), 1);
            }
            else if (g.inFront[i] === 1) {
                ctx.fillStyle = rgba(MINT, 0.9);
                ctx.fillRect(cellX(i) + 2, cellY(i) + 2, CS - 4, CS - 4);
            }
        }
        strokeWalls(g.walls, rgba(INK, 1), 2);
        if (!done()) {
            ctx.fillStyle = rgba(PINK, 1);
            ctx.fillRect(cellX(g.last) + 1, cellY(g.last) + 1, CS - 2, CS - 2);
        }
        drawGates();
        panelRow(0, '掘ったマス', String(g.count) + ' / ' + String(CELL_N));
        panelRow(1, 'フロンティア', String(g.front.length));
        panelRow(2, '波紋の帯', String(Math.ceil(g.count / RIPPLE_W)));
        panelRow(3, '選び方', modeName(mode));
    }
    function after() {
        if (still) {
            settle();
        }
        report();
        draw();
    }
    function restart(s) {
        pass += 1;
        reset(s);
        after();
    }
    function nextMode() {
        mode = MODES[(MODES.indexOf(mode) + 1) % MODES.length];
        restart(start);
    }
    cv.addEventListener('pointerdown', function (ev) {
        wake();
        const p = toScene(ev);
        const c = cellAt(p[0], p[1]);
        if (c >= 0) {
            restart(c);
        }
    });
    cv.addEventListener('keydown', function (ev) {
        if (ev.key === 'Enter') {
            ev.preventDefault();
            wake();
            nextMode();
        }
        else if (ev.key === 'ArrowRight') {
            ev.preventDefault();
            wake();
            grow(40);
            after();
        }
        else if (ev.key === 'Home') {
            ev.preventDefault();
            wake();
            restart(CENTER);
        }
    });
    if (restartBtn) {
        restartBtn.addEventListener('click', function () { wake(); restart(CENTER); });
    }
    if (modeBtn) {
        modeBtn.addEventListener('click', function () { wake(); nextMode(); });
    }
    report();
    let rafId = 0;
    let lastTs = -1;
    let acc = 0;
    let clock = 0;
    function frame(ts) {
        if (lastTs < 0) {
            lastTs = ts;
        }
        // 탭이 숨었다 돌아와도 한 번에 100ms 까지만 따라잡는다 — 순간이동 대신 이어서 움직인다
        acc += Math.min(ts - lastTs, 100);
        lastTs = ts;
        let n = 0;
        while (acc >= FIXED_DT && n < 6) {
            clock += FIXED_DT;
            if (demo) {
                demoTick(clock);
            }
            step();
            acc -= FIXED_DT;
            n += 1;
        }
        draw();
        rafId = window.requestAnimationFrame(frame);
    }
    if (still) {
        settle();
        draw();
    }
    else {
        rafId = window.requestAnimationFrame(frame);
    }
    return function () {
        window.cancelAnimationFrame(rafId);
        window.removeEventListener('resize', onResize);
    };
})();

// MzFrontierRippleGrowth - vanilla 판(02-mz-frontier-ripple-growth) 의 React 포트. 같은 계산을 useEffect 안에서 돌린다.
import { useEffect, useRef } from "react";
import styles from "./MzFrontierRippleGrowth.module.scss";

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

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

  useEffect(() => {
    const rootEl = rootRef.current;
    if (!rootEl) return;
    const root: HTMLElement = rootEl;
    type RGB = [number, number, number];
    const W = 480;
    const H = 300;
    const FIXED_DT = 16;
    // 파스텔 팔레트 — 어두운 무대 위에 밝은 바닥을 얹어 명도 차로 길이 읽힌다
    const BG: RGB = [29, 26, 44];
    const ROCK: RGB = [44, 39, 64];
    const PAPER: RGB = [255, 248, 234];
    const INK: RGB = [58, 48, 76];
    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];
    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 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)]; }
    const canvasEl = root.querySelector('[data-role="canvas"]') as HTMLCanvasElement | null;
    const statusEl = root.querySelector('[data-role="status"]') as HTMLElement | null;
    const ctxRaw = canvasEl ? canvasEl.getContext('2d') : null;
    if (!canvasEl || !ctxRaw || !statusEl) { return; }
    const cv: HTMLCanvasElement = canvasEl;
    const ctx: CanvasRenderingContext2D = ctxRaw;
    const status: HTMLElement = statusEl;
    const reduceQuery = window.matchMedia('(prefers-reduced-motion: reduce)');
    const still = reduceQuery.matches;
    // 자동 시연 중인가 — 사람이 처음 만지는 순간 시연을 멈추고 상태 줄을 읽어 주기 시작한다
    let demo = root.classList.contains('is-demo');
    function wake(): void {
        if (!demo) { return; }
        demo = false;
        root.classList.remove('is-demo');
        status.setAttribute('aria-live', 'polite');
    }
    function say(text: string): void {
        if (status.textContent !== text) { status.textContent = text; }
    }
    function fitCanvas(): void {
        // 배율은 2 에서 자른다 — 배율 3 기기에서 화소가 2.25배로 늘어 프레임마다 일이 그만큼 커지지 않게
        const dpr = Math.min(window.devicePixelRatio || 1, 2);
        cv.width = Math.round(W * dpr);
        cv.height = Math.round(H * dpr);
        ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
    }
    function onResize(): void {
        fitCanvas();
        draw();
    }
    fitCanvas();
    window.addEventListener('resize', onResize);
    // 화면 좌표(CSS px) → 장면 좌표(480x300). 리사이즈 뒤에도 늘 현재 크기로 다시 잰다
    function toScene(ev: PointerEvent): [number, number] {
        const r = cv.getBoundingClientRect();
        return [((ev.clientX - r.left) / r.width) * W, ((ev.clientY - r.top) / r.height) * H];
    }
    // 시드 고정 난수 — 같은 시드면 같은 미로가 다시 나온다 (32비트 정수 섞기)
    function makeRng(seed: number): () => number {
        let s = seed >>> 0;
        return function (): number {
            s = (s + 0x6d2b79f5) >>> 0;
            let t = s;
            t = Math.imul(t ^ (t >>> 15), t | 1);
            t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
            return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
        };
    }
    // 격자 — 31×31 칸, 칸마다 벽 네 장을 비트 하나씩으로 든다
    const GRID_N = 31;
    const CELL_N = GRID_N * GRID_N;
    const CS = 9;
    const BOARD = GRID_N * CS;
    let BX = W - 12 - BOARD;
    const BY = (H - BOARD) / 2;
    const ENTRY = 0;
    const EXIT = CELL_N - 1;
    // 방향 0 북 · 1 동 · 2 남 · 3 서 — 시계 방향 순서라 +1 이 오른쪽으로 돌기, +3 이 왼쪽으로 돌기
    const DX = [0, 1, 0, -1];
    const DY = [-1, 0, 1, 0];
    const BIT = [1, 2, 4, 8];
    const ALL_WALLS = 15;
    function neighbor(i: number, d: number): number {
        const x = (i % GRID_N) + DX[d];
        const y = Math.floor(i / GRID_N) + DY[d];
        return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
    }
    function isOpen(walls: Uint8Array, i: number, d: number): boolean {
        return (walls[i] & BIT[d]) === 0 && neighbor(i, d) >= 0;
    }
    // 벽 한 장 걷기 — 양쪽 칸의 비트를 함께 지운다 (한쪽만 지우면 길이 일방통행이 된다)
    function knock(walls: Uint8Array, i: number, d: number): number {
        const n = neighbor(i, d);
        walls[i] &= ~BIT[d];
        walls[n] &= ~BIT[(d + 2) % 4];
        return n;
    }
    function openCount(walls: Uint8Array, i: number): number {
        let c = 0;
        for (let d = 0; d < 4; d += 1) { if (isOpen(walls, i, d)) { c += 1; } }
        return c;
    }
    function cellX(i: number): number { return BX + (i % GRID_N) * CS; }
    function cellY(i: number): number { return BY + Math.floor(i / GRID_N) * CS; }
    function cellAt(sx: number, sy: number): number {
        const x = Math.floor((sx - BX) / CS);
        const y = Math.floor((sy - BY) / CS);
        return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
    }
    function fillCell(i: number, c: RGB, a: number): void {
        ctx.fillStyle = rgba(c, a);
        ctx.fillRect(cellX(i), cellY(i), CS, CS);
    }
    // 벽 비트를 선분으로 — 칸마다 동·남 벽만 긋고 맨 윗줄·맨 왼줄만 북·서 벽을 더 긋는다 (같은 벽을 두 번 긋지 않는다)
    function strokeWalls(walls: Uint8Array, color: string, lw: number): void {
        ctx.beginPath();
        for (let i = 0; i < CELL_N; i += 1) {
            const x = cellX(i);
            const y = cellY(i);
            const w = walls[i];
            if ((w & 2) !== 0) { ctx.moveTo(x + CS, y); ctx.lineTo(x + CS, y + CS); }
            if ((w & 4) !== 0) { ctx.moveTo(x, y + CS); ctx.lineTo(x + CS, y + CS); }
            if (i < GRID_N && (w & 1) !== 0) { ctx.moveTo(x, y); ctx.lineTo(x + CS, y); }
            if (i % GRID_N === 0 && (w & 8) !== 0) { ctx.moveTo(x, y); ctx.lineTo(x, y + CS); }
        }
        ctx.strokeStyle = color;
        ctx.lineWidth = lw;
        ctx.lineCap = 'square';
        ctx.stroke();
    }
    // 입구(왼쪽 위)·출구(오른쪽 아래) 표시 — 바깥 벽 밖에 작은 삼각형
    function drawGates(): void {
        ctx.fillStyle = rgba(MINT, 0.95);
        ctx.beginPath();
        ctx.moveTo(BX - 9, BY + 1);
        ctx.lineTo(BX - 2, BY + CS / 2);
        ctx.lineTo(BX - 9, BY + CS - 1);
        ctx.closePath();
        ctx.fill();
        ctx.fillStyle = rgba(PINK, 0.95);
        ctx.beginPath();
        ctx.moveTo(BX + BOARD + 2, BY + BOARD - CS + 1);
        ctx.lineTo(BX + BOARD + 9, BY + BOARD - CS / 2);
        ctx.lineTo(BX + BOARD + 2, BY + BOARD - 1);
        ctx.closePath();
        ctx.fill();
    }
    // 왼쪽 칸의 수치 — 이름표 한 줄 + 값 한 줄
    function panelRow(row: number, label: string, value: string): void {
        const y = 104 + row * 34;
        ctx.textAlign = 'left';
        ctx.textBaseline = 'alphabetic';
        ctx.fillStyle = rgba(PAPER, 0.62);
        ctx.font = '500 11px sans-serif';
        ctx.fillText(label, 16, y);
        ctx.fillStyle = rgba(PAPER, 0.96);
        ctx.font = '700 15px sans-serif';
        ctx.fillText(value, 16, y + 18);
    }
    function clearStage(): void {
        ctx.fillStyle = rgba(BG, 1);
        ctx.fillRect(0, 0, W, H);
    }
    type PickMode = 'random' | 'newest' | 'oldest';
    type Grower = { walls: Uint8Array; inMaze: Uint8Array; inFront: Uint8Array; front: number[]; order: Int32Array; count: number; last: number; rnd: () => number };
    function addFront(g: Grower, c: number): void {
        for (let d = 0; d < 4; d += 1) {
            const n = neighbor(c, d);
            if (n < 0 || g.inMaze[n] === 1 || g.inFront[n] === 1) { continue; }
            g.inFront[n] = 1;
            g.front.push(n);
        }
    }
    function growStart(seed: number, start: number): Grower {
        const g: Grower = { walls: new Uint8Array(CELL_N).fill(ALL_WALLS), inMaze: new Uint8Array(CELL_N), inFront: new Uint8Array(CELL_N), front: [], order: new Int32Array(CELL_N).fill(-1), count: 0, last: start, rnd: makeRng(seed) };
        g.inMaze[start] = 1;
        g.order[start] = 0;
        g.count = 1;
        addFront(g, start);
        return g;
    }
    // 프론티어(판 영역에 닿은 안 판 칸)에서 하나를 골라 이미 판 이웃 하나와 벽 한 장으로 잇는다
    function growOne(g: Grower, mode: PickMode): number {
        const len = g.front.length;
        if (len === 0) { return -1; }
        let c = 0;
        if (mode === 'newest') {
            c = g.front.pop() as number;
        } else if (mode === 'oldest') {
            c = g.front.shift() as number;
        } else {
            const k = Math.floor(g.rnd() * len);
            c = g.front[k];
            g.front[k] = g.front[len - 1];
            g.front.pop();
        }
        g.inFront[c] = 0;
        const links: number[] = [];
        for (let d = 0; d < 4; d += 1) {
            const n = neighbor(c, d);
            if (n >= 0 && g.inMaze[n] === 1) { links.push(d); }
        }
        knock(g.walls, c, links[Math.floor(g.rnd() * links.length)]);
        g.inMaze[c] = 1;
        g.order[c] = g.count;
        g.count += 1;
        g.last = c;
        addFront(g, c);
        return c;
    }
    function growAll(seed: number, start: number, mode: PickMode): Uint8Array {
        const g = growStart(seed, start);
        while (growOne(g, mode) >= 0) { /* 프론티어가 빌 때까지 */ }
        return g.walls;
    }
    // 프론티어에서 다음 칸을 고르는 법 — random 은 아무거나, newest 는 막 들어온 것, oldest 는 가장 먼저 들어온 것
    const FRONTIER_PICK: PickMode = 'random';
    // 편입 순번 몇 개마다 물결 띠 하나를 두르나
    const RIPPLE_W = 26;
    // 띠가 생긴 뒤 칸이 하나 더 들어올 때마다 그 띠 색이 옅어지는 비율 (지수 감쇠)
    const RING_FADE = 0.0035;
    const GROW_MS = 8;
    const SEED = 464;
    const HOLD_MS = 1400;
    const CENTER = Math.floor(GRID_N / 2) * GRID_N + Math.floor(GRID_N / 2);
    const MODES: PickMode[] = ['random', 'newest', 'oldest'];
    const TXT_GROW = '프론티어에서 한 칸씩 골라 붙이는 중';
    const TXT_DONE = '완성 — 벽 960장을 걷어 한 판이 됨';
    const restartBtn = root.querySelector('[data-role="restart"]') as HTMLButtonElement | null;
    const modeBtn = root.querySelector('[data-role="mode"]') as HTMLButtonElement | null;
    let mode: PickMode = FRONTIER_PICK;
    let pass = 0;
    let start = CENTER;
    let grower = growStart(SEED, start);
    let stepAcc = 0;
    let holdLeft = 0;
    function modeName(m: PickMode): string {
        return m === 'random' ? '무작위' : (m === 'newest' ? '막 들어온 칸' : '먼저 들어온 칸');
    }
    function done(): boolean { return grower.front.length === 0; }
    function report(): void { say(done() ? TXT_DONE : TXT_GROW); }
    function reset(s: number): void {
        start = s;
        grower = growStart(SEED + pass, s);
        stepAcc = 0;
        holdLeft = 0;
    }
    function grow(n: number): void {
        for (let k = 0; k < n && !done(); k += 1) { growOne(grower, mode); }
    }
    function step(): void {
        if (done()) { return; }
        stepAcc += FIXED_DT;
        while (stepAcc >= GROW_MS && !done()) {
            stepAcc -= GROW_MS;
            growOne(grower, mode);
        }
        report();
    }
    function settle(): void {
        grow(CELL_N);
        report();
    }
    function demoTick(t: number): void {
        if (!done() || t < 0) { return; }
        holdLeft += FIXED_DT;
        if (holdLeft >= HOLD_MS) {
            pass += 1;
            reset(CENTER);
        }
    }
    const BAND_A = SKY;
    const BAND_B = LILAC;
    const OLD_PALE = mix(PAPER, BG, 0.05);
    function draw(): void {
        clearStage();
        ctx.fillStyle = rgba(ROCK, 1);
        ctx.fillRect(BX, BY, BOARD, BOARD);
        const g = grower;
        for (let i = 0; i < CELL_N; i += 1) {
            if (g.inMaze[i] === 1) {
                const o = g.order[i];
                const band = Math.floor(o / RIPPLE_W) % 2 === 0 ? BAND_A : BAND_B;
                const k = Math.exp(-(g.count - o) * RING_FADE);
                fillCell(i, mix(OLD_PALE, band, 0.22 + 0.78 * k), 1);
            } else if (g.inFront[i] === 1) {
                ctx.fillStyle = rgba(MINT, 0.9);
                ctx.fillRect(cellX(i) + 2, cellY(i) + 2, CS - 4, CS - 4);
            }
        }
        strokeWalls(g.walls, rgba(INK, 1), 2);
        if (!done()) {
            ctx.fillStyle = rgba(PINK, 1);
            ctx.fillRect(cellX(g.last) + 1, cellY(g.last) + 1, CS - 2, CS - 2);
        }
        drawGates();
        panelRow(0, '판 칸', String(g.count) + ' / ' + String(CELL_N));
        panelRow(1, '프론티어', String(g.front.length));
        panelRow(2, '물결 띠', String(Math.ceil(g.count / RIPPLE_W)));
        panelRow(3, '고르는 법', modeName(mode));
    }
    function after(): void {
        if (still) { settle(); }
        report();
        draw();
    }
    function restart(s: number): void {
        pass += 1;
        reset(s);
        after();
    }
    function nextMode(): void {
        mode = MODES[(MODES.indexOf(mode) + 1) % MODES.length];
        restart(start);
    }
    cv.addEventListener('pointerdown', function (ev: PointerEvent): void {
        wake();
        const p = toScene(ev);
        const c = cellAt(p[0], p[1]);
        if (c >= 0) { restart(c); }
    });
    cv.addEventListener('keydown', function (ev: KeyboardEvent): void {
        if (ev.key === 'Enter') { ev.preventDefault(); wake(); nextMode(); }
        else if (ev.key === 'ArrowRight') { ev.preventDefault(); wake(); grow(40); after(); }
        else if (ev.key === 'Home') { ev.preventDefault(); wake(); restart(CENTER); }
    });
    if (restartBtn) { restartBtn.addEventListener('click', function (): void { wake(); restart(CENTER); }); }
    if (modeBtn) { modeBtn.addEventListener('click', function (): void { wake(); nextMode(); }); }
    report();

    let rafId = 0;
    let lastTs = -1;
    let acc = 0;
    let clock = 0;
    function frame(ts: number): void {
        if (lastTs < 0) { lastTs = ts; }
        // 탭이 숨었다 돌아와도 한 번에 100ms 까지만 따라잡는다 — 순간이동 대신 이어서 움직인다
        acc += Math.min(ts - lastTs, 100);
        lastTs = ts;
        let n = 0;
        while (acc >= FIXED_DT && n < 6) {
            clock += FIXED_DT;
            if (demo) { demoTick(clock); }
            step();
            acc -= FIXED_DT;
            n += 1;
        }
        draw();
        rafId = window.requestAnimationFrame(frame);
    }
    if (still) {
        settle();
        draw();
    } else {
        rafId = window.requestAnimationFrame(frame);
    }
    return function (): void {
        window.cancelAnimationFrame(rafId);
        window.removeEventListener('resize', onResize);
    };

  }, []);

  return (
    <div className={cx("hs") + " is-demo"} ref={rootRef}>
        <canvas className={cx("hs__canvas")} data-role="canvas" width={480} height={300} tabIndex={0} aria-label="판 영역에 닿은 칸 목록에서 하나씩 골라 붙이며 편입 순번이 물결 띠로 남는 미로. 칸을 누르면 그 칸에서 다시 키운다"></canvas>
        <p className={cx("hs__status")} data-role="status" aria-live="off">프론티어에서 한 칸씩 골라 붙이는 중</p>
        <div className={cx("hs__tools")}>
          <button className={cx("hs__btn")} data-role="restart" type="button">다시 키우기</button>
          <button className={cx("hs__btn")} data-role="mode" type="button">고르는 법 바꾸기</button>
        </div>
    </div>
  );
}