01Called Number Whose Digits Roll After Recalculating the Remaining Count

<main class="stage">
<div class="wcn is-demo" id="wcnRoot">
  <div class="wcn__board">
    <div class="wcn__odometer" id="wcnCallOdo" aria-hidden="true"></div>
    <div class="wcn__remainWrap" aria-hidden="true">
      <span class="wcn__remainLabel">Left:</span>
      <div class="wcn__odometer wcn__odometer--small" id="wcnRemainOdo"></div>
      <span class="wcn__remainUnit"> </span>
    </div>
  </div>
  <p class="wcn__status" id="wcnStatus" aria-live="polite"></p>
  <div class="wcn__controls">
    <button type="button" class="wcn__btn" id="wcnReset">Start over</button>
    <button type="button" class="wcn__btn wcn__btn--primary" id="wcnNext">Call next</button>
  </div>
</div>
</main>

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

// 핵심: 순번·남은인원 두 오도미터 모두 자리별 릴로 굴러간다. 남은인원은 총원에서
// 호출된 인원 수를 뺀 값을 매 호출마다 다시 계산해서 자리 단위로 내려간다.

@include stage($stage-ink);

.wcn {
  position: relative;
  display: grid;
  gap: $sp-4;
  justify-items: center;
  width: min(90vw, 300px);
}

.wcn__board {
  border-radius: $r-card;
  display: grid;
  gap: $sp-3;
  justify-items: center;
}

.wcn__odometer {
  display: flex;
  gap: $sp-1;
  font-variant-numeric: tabular-nums;
}

.wcn__digit {
  position: relative;
  width: 54px;
  height: 80px;
  overflow: hidden;
  border-radius: $r-xs;
  background: rgba($stage-paper, .08);
}

.wcn__odometer--small .wcn__digit {
  width: 34px;
  height: 52px;
}

.wcn__reel {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
}

.wcn__reel i {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 80px;
  font-style: normal;
  font-size: 52px;
  font-weight: 700;
  color: $subject-blue-light;
}

.wcn__odometer--small .wcn__reel i {
  height: 52px;
  font-size: 32px;
  color: $stage-paper;
}

.wcn__remainWrap {
  display: flex;
  align-items: center;
  gap: $sp-2;
}

.wcn__remainLabel,
.wcn__remainUnit {
  font-size: 12px;
  font-weight: 600;
  color: rgba($stage-paper, .72);
}

.wcn__status {
  margin: 0;
  font-size: 11px;
  font-weight: 600;
  color: rgba($stage-paper, .7);
}

.wcn__controls {
  display: flex;
  gap: $sp-2;
}

.wcn__btn {
  border: 1px solid rgba($stage-paper, .3);
  background: transparent;
  color: $stage-paper;
  border-radius: $r-control;
  padding: $sp-2 $sp-4;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
}

.wcn__btn--primary {
  background: $subject-blue-deep;
  border-color: $subject-blue-deep;
  color: $stage-paper;
}

.wcn__btn:focus-visible {
  outline: 2px solid $subject-blue-light;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .wcn__digit { width: 30px; height: 44px; }
  .wcn__reel i { height: 44px; font-size: 28px; }
  .wcn__odometer--small .wcn__digit { width: 22px; height: 32px; }
  .wcn__odometer--small .wcn__reel i { height: 32px; font-size: 20px; }
}

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

// 호출 신호 — 새 번호가 불릴 때마다 보드 전체가 한 번 밝아졌다 가라앉는다.
.wcn__board.is-flash { animation: wcnFlash 900ms ease-out; }

@keyframes wcnFlash {
  from { background: rgba($subject-blue-deep, .38); }
  to { background: rgba($subject-blue-deep, 0); }
}

@media (prefers-reduced-motion: reduce) {
  .wcn__board.is-flash { animation: 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);
}

.wcn {
  position: relative;
  display: grid;
  gap: 16px;
  justify-items: center;
  width: min(90vw, 300px);
}

.wcn__board {
  border-radius: 16px;
  display: grid;
  gap: 12px;
  justify-items: center;
}

.wcn__odometer {
  display: flex;
  gap: 4px;
  font-variant-numeric: tabular-nums;
}

.wcn__digit {
  position: relative;
  width: 54px;
  height: 80px;
  overflow: hidden;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.08);
}

.wcn__odometer--small .wcn__digit {
  width: 34px;
  height: 52px;
}

.wcn__reel {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
}

.wcn__reel i {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 80px;
  font-style: normal;
  font-size: 52px;
  font-weight: 700;
  color: #5b8cf8;
}

.wcn__odometer--small .wcn__reel i {
  height: 52px;
  font-size: 32px;
  color: #ffffff;
}

.wcn__remainWrap {
  display: flex;
  align-items: center;
  gap: 8px;
}

.wcn__remainLabel,
.wcn__remainUnit {
  font-size: 12px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.72);
}

.wcn__status {
  margin: 0;
  font-size: 11px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.7);
}

.wcn__controls {
  display: flex;
  gap: 8px;
}

.wcn__btn {
  border: 1px solid rgba(255, 255, 255, 0.3);
  background: transparent;
  color: #ffffff;
  border-radius: 12px;
  padding: 8px 16px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
}

.wcn__btn--primary {
  background: #0a4fe8;
  border-color: #0a4fe8;
  color: #ffffff;
}

.wcn__btn:focus-visible {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .wcn__digit {
    width: 30px;
    height: 44px;
  }
  .wcn__reel i {
    height: 44px;
    font-size: 28px;
  }
  .wcn__odometer--small .wcn__digit {
    width: 22px;
    height: 32px;
  }
  .wcn__odometer--small .wcn__reel i {
    height: 32px;
    font-size: 20px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .wcn__reel {
    transition: none;
  }
}
.wcn__board.is-flash {
  animation: wcnFlash 900ms ease-out;
}

@keyframes wcnFlash {
  from {
    background: rgba(10, 79, 232, 0.38);
  }
  to {
    background: rgba(10, 79, 232, 0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .wcn__board.is-flash {
    animation: none;
  }
}

(function () {
  // 기법: 새 순번이 호출될 때마다 Left: 대기 인원(총원 - 처리된 인원)을 다시 계산해, 그 차이를
  // 자릿수 릴(디지트 릴)로 자리마다 순서대로 굴려 내린다. 순번 숫자 자체도 자리별 릴이며,
  // CALL_NUMBER_ROLL_MS 는 한 자리가 다음 값으로 굴러가는 데 걸리는 시간, DIGIT_STAGGER_MS 는
  // 자리마다 시작을 늦추는 간격이다 — CSS 트랜지션이 아니라 rAF 로 각 릴의 위치를 계산한다.
  var CALL_NUMBER_ROLL_MS = 480;
  var DIGIT_STAGGER_MS = 70;

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var rand = seedRand(434011);

  var TOTAL_PARTIES = 42;
  var CALL_BASE = 101;
  var callIndex = 0; // 지금까지 호출된 인원 수

  var root = document.getElementById('wcnRoot');
  var callOdo = document.getElementById('wcnCallOdo');
  var remainOdo = document.getElementById('wcnRemainOdo');
  var status = document.getElementById('wcnStatus');

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (reduce) root.classList.remove('is-demo');

  function easeInOutCubic(t) {
    return t < 0.5 ? 4 * t * t * t : 1 - Math.pow(-2 * t + 2, 3) / 2;
  }

  // 자릿수 릴: 각 digit 은 {el, from, to, startMs, doneMs}
  function buildOdometer(container, digitCount) {
    container.innerHTML = '';
    var digits = [];
    for (var i = 0; i < digitCount; i += 1) {
      var d = document.createElement('div');
      d.className = 'wcn__digit';
      var reel = document.createElement('div');
      reel.className = 'wcn__reel';
      d.appendChild(reel);
      container.appendChild(d);
      digits.push({ el: d, reel: reel, value: 0, from: 0, to: 0, start: 0, dur: 0 });
    }
    return digits;
  }

  var callDigits = buildOdometer(callOdo, 3);
  var remainDigits = buildOdometer(remainOdo, 2);

  function paintReel(digit, value) {
    var reel = digit.reel;
    if (reel.childElementCount !== 10) {
      reel.innerHTML = '';
      for (var n = 0; n < 10; n += 1) {
        var i = document.createElement('i');
        i.textContent = String(n);
        reel.appendChild(i);
      }
    }
    reel.style.transform = 'translateY(' + (-value * 10) + '%)';
  }

  function setDigitsImmediate(digits, num) {
    var s = String(num);
    while (s.length < digits.length) s = '0' + s;
    for (var i = 0; i < digits.length; i += 1) {
      var v = Number(s[i]);
      digits[i].value = v;
      digits[i].from = v;
      digits[i].to = v;
      digits[i].dur = 0;
      paintReel(digits[i], v);
    }
  }

  function flash(el) {
    if (reduce) return;
    el.classList.remove('is-flash');
    void el.offsetWidth;
    el.classList.add('is-flash');
  }
  function rollDigits(digits, num, nowMs) {
    if (reduce) { setDigitsImmediate(digits, num); return; }
    flash(callOdo.parentNode);
    var s = String(num);
    while (s.length < digits.length) s = '0' + s;
    for (var i = 0; i < digits.length; i += 1) {
      var v = Number(s[i]);
      if (v === digits[i].to) continue;
      digits[i].from = digits[i].value;
      digits[i].to = v;
      digits[i].start = nowMs + i * DIGIT_STAGGER_MS;
      digits[i].dur = CALL_NUMBER_ROLL_MS;
    }
  }

  function stepDigits(digits, nowMs) {
    for (var i = 0; i < digits.length; i += 1) {
      var d = digits[i];
      if (d.value === d.to && nowMs >= d.start) continue;
      if (nowMs < d.start) continue;
      var t = Math.min(1, (nowMs - d.start) / d.dur);
      var e = easeInOutCubic(t);
      var span = d.to - d.from;
      // 두 자리 사이를 최단 방향으로 굴린다(9→0 처럼 넘어가는 경우 고려).
      if (Math.abs(span) > 5) span = span > 0 ? span - 10 : span + 10;
      var cur = d.from + span * e;
      cur = ((cur % 10) + 10) % 10;
      d.value = t >= 1 ? d.to : cur;
      paintReel(d, cur);
    }
  }

  var callNum = CALL_BASE;
  var remain = TOTAL_PARTIES;
  setDigitsImmediate(callDigits, 0);
  setDigitsImmediate(remainDigits, remain);

  function paintStatus() {
    status.textContent = 'Now calling ' + callNum + ' · ' + remain + ' ';
  }

  function callNext(nowMs) {
    if (remain <= 0) { paintStatus(); return; }
    callIndex += 1;
    callNum = CALL_BASE + callIndex - 1;
    remain = Math.max(0, TOTAL_PARTIES - callIndex);
    rollDigits(callDigits, callNum, nowMs);
    rollDigits(remainDigits, remain, nowMs);
    paintStatus();
  }

  function resetAll(nowMs) {
    callIndex = 0;
    callNum = CALL_BASE;
    remain = TOTAL_PARTIES;
    rollDigits(callDigits, 0, nowMs);
    rollDigits(remainDigits, remain, nowMs);
    paintStatus();
  }

  var nextBtn = document.getElementById('wcnNext');
  var resetBtn = document.getElementById('wcnReset');

  function onNext() {
    root.classList.remove('is-demo');
    callNext(perfNow());
  }
  function onReset() {
    root.classList.remove('is-demo');
    resetAll(perfNow());
  }

  nextBtn.addEventListener('click', onNext);
  nextBtn.addEventListener('keydown', function (e) {
    if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); onNext(); }
  });
  resetBtn.addEventListener('click', onReset);
  resetBtn.addEventListener('keydown', function (e) {
    if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); onReset(); }
  });

  var t0 = null;
  function perfNow() { return t0 === null ? 0 : performance.now() - t0; }

  // 시연 스케줄: 첫 변화는 200ms 뒤, 이후 자연스러운 간격으로 반복.
  var demoSchedule = [200, 1200];
  var demoIndex = 0;

  function tick(ts) {
    if (t0 === null) t0 = ts;
    var now = ts - t0;
    if (!reduce) {
      stepDigits(callDigits, now);
      stepDigits(remainDigits, now);
      if (root.classList.contains('is-demo') && demoIndex < demoSchedule.length && now >= demoSchedule[demoIndex]) {
        if (remain <= 0) { resetAll(now); } else { callNext(now); }
        demoIndex += 1;
        if (demoIndex >= demoSchedule.length) demoIndex = 0, demoSchedule = demoSchedule.map(function (v) { return v + now + 2000; });
      }
    }
    requestAnimationFrame(tick);
  }

  if (reduce) {
    paintStatus();
  } else {
    requestAnimationFrame(tick);
  }
})();

// WaitingQueueCallNumberRoll — vanilla 판(01-waiting-queue-call-number-roll-remaining) 의 React 포트.
// 새 순번이 호출될 때마다 남은 대기 인원(총원 - 호출된 인원)을 다시 계산해 자릿수 릴로 굴려 내리고,
// 순번 숫자도 자리마다 CALL_NUMBER_ROLL_MS 동안 굴러간다 — CSS 트랜지션이 아니라 rAF 보간.
import { useEffect, useRef, useState } from "react";
import styles from "./WaitingQueueCallNumberRoll.module.scss";

type Box<T> = { current: T };

const CALL_NUMBER_ROLL_MS = 480;
const DIGIT_STAGGER_MS = 70;
const TOTAL_PARTIES = 42;
const CALL_BASE = 101;

function seedRand(seed: number): () => number {
  let s = seed >>> 0;
  return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
}

function easeInOutCubic(t: number): number {
  return t < 0.5 ? 4 * t * t * t : 1 - Math.pow(-2 * t + 2, 3) / 2;
}

type Digit = { value: number; from: number; to: number; start: number; dur: number };

function digitsOf(n: number, len: number): number[] {
  const s = String(n).padStart(len, "0");
  const out: number[] = [];
  for (let i = 0; i < s.length; i += 1) out.push(s.charCodeAt(i) - 48);
  return out;
}

function flash(el: HTMLElement | null, cls: string, reduce: boolean): void {
  if (reduce || !el) return;
  el.classList.remove(cls);
  void el.offsetWidth;
  el.classList.add(cls);
}

export default function WaitingQueueCallNumberRoll() {
  seedRand(434011);
  const [status, setStatus] = useState("");
  const [reduce, setReduce] = useState(false);
  const callDigitsRef = useRef<Digit[]>([{ value: 0, from: 0, to: 0, start: 0, dur: 0 }, { value: 0, from: 0, to: 0, start: 0, dur: 0 }, { value: 0, from: 0, to: 0, start: 0, dur: 0 }]) as Box<Digit[]>;
  const remainDigitsRef = useRef<Digit[]>([{ value: 0, from: 0, to: 0, start: 0, dur: 0 }, { value: 0, from: 0, to: 0, start: 0, dur: 0 }]) as Box<Digit[]>;
  const callReelRefs = useRef<Array<HTMLDivElement | null>>([null, null, null]) as Box<Array<HTMLDivElement | null>>;
  const remainReelRefs = useRef<Array<HTMLDivElement | null>>([null, null]) as Box<Array<HTMLDivElement | null>>;
  const callNumRef = useRef<number>(CALL_BASE) as Box<number>;
  const remainRef = useRef<number>(TOTAL_PARTIES) as Box<number>;
  const callIndexRef = useRef<number>(0) as Box<number>;
  const demoRef = useRef<boolean>(true) as Box<boolean>;
  const demoIndexRef = useRef<number>(0) as Box<number>;
  const demoScheduleRef = useRef<number[]>([200, 1200]) as Box<number[]>;
  const frameRef = useRef<number>(0) as Box<number>;
  const boardRef = useRef<HTMLDivElement | null>(null) as Box<HTMLDivElement | null>;

  useEffect(() => {
    setReduce(window.matchMedia("(prefers-reduced-motion: reduce)").matches);
  }, []);

  function paintReel(el: HTMLDivElement | null, value: number): void {
    if (!el) return;
    el.style.transform = "translateY(" + (-value * 10) + "%)";
  }

  function rollDigits(digits: Digit[], num: number, nowMs: number): void {
    if (digits === callDigitsRef.current) flash(boardRef.current, styles.isFlash, reduce);
    const s = digitsOf(num, digits.length);
    if (reduce) {
      const refs = digits === callDigitsRef.current ? callReelRefs.current : remainReelRefs.current;
      for (let i = 0; i < digits.length; i += 1) {
        digits[i].value = s[i]; digits[i].from = s[i]; digits[i].to = s[i]; digits[i].dur = 0;
        paintReel(refs[i], s[i]);
      }
      return;
    }
    for (let i = 0; i < digits.length; i += 1) {
      const v = s[i];
      if (v === digits[i].to) continue;
      digits[i].from = digits[i].value;
      digits[i].to = v;
      digits[i].start = nowMs + i * DIGIT_STAGGER_MS;
      digits[i].dur = CALL_NUMBER_ROLL_MS;
    }
  }

  function stepDigits(digits: Digit[], refs: Array<HTMLDivElement | null>, nowMs: number): void {
    for (let i = 0; i < digits.length; i += 1) {
      const d = digits[i];
      if (d.value === d.to && nowMs >= d.start) continue;
      if (nowMs < d.start) continue;
      const t = Math.min(1, (nowMs - d.start) / d.dur);
      const e = easeInOutCubic(t);
      let span = d.to - d.from;
      if (Math.abs(span) > 5) span = span > 0 ? span - 10 : span + 10;
      let cur = d.from + span * e;
      cur = ((cur % 10) + 10) % 10;
      d.value = t >= 1 ? d.to : cur;
      paintReel(refs[i], cur);
    }
  }

  function paintStatus(): void {
    setStatus("호출 번호 " + callNumRef.current + " · 남은 " + remainRef.current + "명");
  }

  function callNext(nowMs: number): void {
    if (remainRef.current <= 0) { paintStatus(); return; }
    callIndexRef.current += 1;
    callNumRef.current = CALL_BASE + callIndexRef.current - 1;
    remainRef.current = Math.max(0, TOTAL_PARTIES - callIndexRef.current);
    rollDigits(callDigitsRef.current, callNumRef.current, nowMs);
    rollDigits(remainDigitsRef.current, remainRef.current, nowMs);
    paintStatus();
  }

  function resetAll(nowMs: number): void {
    callIndexRef.current = 0;
    callNumRef.current = CALL_BASE;
    remainRef.current = TOTAL_PARTIES;
    rollDigits(callDigitsRef.current, 0, nowMs);
    rollDigits(remainDigitsRef.current, remainRef.current, nowMs);
    paintStatus();
  }

  function stopDemo(): void { demoRef.current = false; }

  useEffect(() => {
    paintStatus();
    let t0 = 0;
    function tick(ts: number): void {
      if (t0 === 0) t0 = ts;
      const now = ts - t0;
      if (!reduce) {
        stepDigits(callDigitsRef.current, callReelRefs.current, now);
        stepDigits(remainDigitsRef.current, remainReelRefs.current, now);
        const sched = demoScheduleRef.current;
        if (demoRef.current && demoIndexRef.current < sched.length && now >= sched[demoIndexRef.current]) {
          if (remainRef.current <= 0) { resetAll(now); } else { callNext(now); }
          demoIndexRef.current += 1;
          if (demoIndexRef.current >= sched.length) {
            demoIndexRef.current = 0;
            demoScheduleRef.current = sched.map((v) => v + now + 2000);
          }
        }
      }
      frameRef.current = requestAnimationFrame(tick);
    }
    frameRef.current = requestAnimationFrame(tick);
    return () => cancelAnimationFrame(frameRef.current);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [reduce]);

  function onNext(): void { stopDemo(); callNext(performance.now()); }
  function onReset(): void { stopDemo(); resetAll(performance.now()); }

  function onKeyDown(e: { key: string; preventDefault: () => void }, fn: () => void): void {
    if (e.key === "Enter" || e.key === " ") { e.preventDefault(); fn(); }
  }

  return (
    <main className={styles.stage}>
      <div className={styles.wcn}>
        <div className={styles.board} ref={boardRef}>
          <div className={styles.odometer} aria-hidden="true">
            {[0, 1, 2].map((i) => (
              <div className={styles.digit} key={i}>
                <div className={styles.reel} ref={(el: HTMLDivElement | null) => { callReelRefs.current[i] = el; }}>
                  {"0123456789".split("").map((ch) => <i key={ch}>{ch}</i>)}
                </div>
              </div>
            ))}
          </div>
          <div className={styles.remainWrap} aria-hidden="true">
            <span className={styles.remainLabel}>남은</span>
            <div className={[styles.odometer, styles.odometerSmall].join(" ")}>
              {[0, 1].map((i) => (
                <div className={styles.digit} key={i}>
                  <div className={styles.reel} ref={(el: HTMLDivElement | null) => { remainReelRefs.current[i] = el; }}>
                    {"0123456789".split("").map((ch) => <i key={ch}>{ch}</i>)}
                  </div>
                </div>
              ))}
            </div>
            <span className={styles.remainUnit}>명</span>
          </div>
        </div>
        <p className={styles.status} aria-live="polite">{status}</p>
        <div className={styles.controls}>
          <button type="button" className={styles.btn} onClick={onReset} onKeyDown={(e: { key: string; preventDefault: () => void }) => onKeyDown(e, onReset)}>처음으로</button>
          <button type="button" className={[styles.btn, styles.btnPrimary].join(" ")} onClick={onNext} onKeyDown={(e: { key: string; preventDefault: () => void }) => onKeyDown(e, onNext)}>다음 호출</button>
        </div>
      </div>
    </main>
  );
}