03완료 비율을 계산해 채워지는 대기열 진행 링

<main class="stage">
<div class="wpr is-demo" id="wprRoot">
  <div class="wpr__ringWrap">
    <svg class="wpr__ring" viewBox="0 0 120 120" aria-hidden="true">
      <circle class="wpr__track" cx="60" cy="60" r="52"></circle>
      <circle class="wpr__fill" id="wprFill" cx="60" cy="60" r="52"></circle>
    </svg>
    <div class="wpr__pct" id="wprPct" aria-hidden="true">0%</div>
  </div>
  <p class="wpr__status" id="wprStatus" aria-live="polite"></p>
  <div class="wpr__controls">
    <button type="button" class="wpr__btn wpr__btn--primary" id="wprProcess">처리 추가</button>
    <button type="button" class="wpr__btn" id="wprReset">초기화</button>
  </div>
</div>
</main>

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

// 핵심: 처리 비율(0~1)을 stroke-dashoffset 으로 환산해 링을 채우고, 비율 구간마다
// 링 색을 세 단계로 계산해 전파한다 — 색은 속성이 아니라 비율값에서 매번 다시 계산된다.

@include stage($stage-orange);

.wpr {
  position: relative;
  display: grid;
  gap: $sp-3;
  justify-items: center;
  width: min(90vw, 300px);
}

.wpr__ringWrap {
  border-radius: 50%;
  position: relative;
  width: 168px;
  height: 168px;
  display: grid;
  place-items: center;
}

.wpr__ring {
  width: 168px;
  height: 168px;
  transform: rotate(-90deg);
}

.wpr__track {
  fill: none;
  stroke: rgba($stage-ink, .18);
  stroke-width: 10;
}

.wpr__fill {
  fill: none;
  stroke: $subject-blue-deep;
  stroke-width: 10;
  stroke-linecap: round;
}

.wpr__fill.is-early { stroke: $subject-blue-deep; }
.wpr__fill.is-mid { stroke: $stage-ink; }
.wpr__fill.is-late { stroke: $tick-up; }

.wpr__pct {
  position: absolute;
  font-size: 24px;
  font-weight: 700;
  color: $stage-ink;
  font-variant-numeric: tabular-nums;
}

.wpr__status {
  margin: 0;
  font-size: 11px;
  font-weight: 600;
  color: rgba($stage-ink, .65);
}

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

.wpr__btn {
  border: 1px solid rgba($stage-ink, .28);
  background: transparent;
  color: $stage-ink;
  border-radius: $r-control;
  padding: $sp-2 $sp-4;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
}

.wpr__btn--primary {
  background: $stage-ink;
  border-color: $stage-ink;
  color: $stage-paper;
}

.wpr__btn:focus-visible {
  outline: 2px solid $stage-ink;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .wpr__ringWrap { width: 104px; height: 104px; }
  .wpr__ring { width: 104px; height: 104px; }
  .wpr__pct { font-size: 19px; }
}

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

@media (max-height: 240px) {
  .wpr { gap: $sp-2; }
  .wpr__status { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
  .wpr__btn { padding-top: $sp-1; padding-bottom: $sp-1; }
}

// 처리 인원이 늘 때마다 링 안쪽이 한 번 밝아졌다 가라앉는다.
.wpr__ringWrap.is-flash { animation: wprFlash 900ms ease-out; }

@keyframes wprFlash {
  from { background: rgba($subject-blue-deep, .3); }
  to { background: rgba($subject-blue-deep, 0); }
}

@media (prefers-reduced-motion: reduce) {
  .wpr__ringWrap.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: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.wpr {
  position: relative;
  display: grid;
  gap: 12px;
  justify-items: center;
  width: min(90vw, 300px);
}

.wpr__ringWrap {
  border-radius: 50%;
  position: relative;
  width: 168px;
  height: 168px;
  display: grid;
  place-items: center;
}

.wpr__ring {
  width: 168px;
  height: 168px;
  transform: rotate(-90deg);
}

.wpr__track {
  fill: none;
  stroke: rgba(23, 20, 26, 0.18);
  stroke-width: 10;
}

.wpr__fill {
  fill: none;
  stroke: #0a4fe8;
  stroke-width: 10;
  stroke-linecap: round;
}

.wpr__fill.is-early {
  stroke: #0a4fe8;
}

.wpr__fill.is-mid {
  stroke: #17141a;
}

.wpr__fill.is-late {
  stroke: #3ddc97;
}

.wpr__pct {
  position: absolute;
  font-size: 24px;
  font-weight: 700;
  color: #17141a;
  font-variant-numeric: tabular-nums;
}

.wpr__status {
  margin: 0;
  font-size: 11px;
  font-weight: 600;
  color: rgba(23, 20, 26, 0.65);
}

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

.wpr__btn {
  border: 1px solid rgba(23, 20, 26, 0.28);
  background: transparent;
  color: #17141a;
  border-radius: 12px;
  padding: 8px 16px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
}

.wpr__btn--primary {
  background: #17141a;
  border-color: #17141a;
  color: #ffffff;
}

.wpr__btn:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .wpr__ringWrap {
    width: 104px;
    height: 104px;
  }
  .wpr__ring {
    width: 104px;
    height: 104px;
  }
  .wpr__pct {
    font-size: 19px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .wpr__fill {
    transition: none;
  }
}
@media (max-height: 240px) {
  .wpr {
    gap: 8px;
  }
  .wpr__status {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
  }
  .wpr__btn {
    padding-top: 4px;
    padding-bottom: 4px;
  }
}
.wpr__ringWrap.is-flash {
  animation: wprFlash 900ms ease-out;
}

@keyframes wprFlash {
  from {
    background: rgba(10, 79, 232, 0.3);
  }
  to {
    background: rgba(10, 79, 232, 0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .wpr__ringWrap.is-flash {
    animation: none;
  }
}

(function () {
  // 기법: 처리된 인원 수를 전체 인원으로 나눈 비율을 다시 계산해 원 둘레(2πr)에서 그 비율만큼을
  // stroke-dashoffset 으로 채운다. 채워지는 동안 RING_FILL_DURATION_MS 로 easeOutCubic 보간하고,
  // 비율 구간(0~1/3, 1/3~2/3, 2/3~1)에 따라 링 색을 세 단계로 계산해 함께 바꾼다.
  var RING_FILL_DURATION_MS = 500;
  var TOTAL = 30;
  var RADIUS = 52;
  var CIRCUMFERENCE = 2 * Math.PI * RADIUS;

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var rand = seedRand(434031);

  function easeOutCubic(t) { return 1 - Math.pow(1 - t, 3); }

  var root = document.getElementById('wprRoot');
  var fillEl = document.getElementById('wprFill');
  var pctEl = document.getElementById('wprPct');
  var status = document.getElementById('wprStatus');

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

  fillEl.style.strokeDasharray = CIRCUMFERENCE.toFixed(2);

  var processed = 0;
  var shownRatio = 0;
  var ringAnim = null;

  function stageOf(ratio) {
    if (ratio >= 2 / 3) return 'is-late';
    if (ratio >= 1 / 3) return 'is-mid';
    return 'is-early';
  }

  function paintRing(ratio) {
    var offset = CIRCUMFERENCE * (1 - ratio);
    fillEl.style.strokeDashoffset = offset.toFixed(2);
    fillEl.classList.remove('is-early', 'is-mid', 'is-late');
    fillEl.classList.add(stageOf(ratio));
    pctEl.textContent = Math.round(ratio * 100) + '%';
  }

  function flash(el) {
    if (reduce) return;
    el.classList.remove('is-flash');
    void el.offsetWidth;
    el.classList.add('is-flash');
  }
  function tweenRing(from, to) {
    flash(fillEl.parentNode.parentNode);
    if (ringAnim) cancelAnimationFrame(ringAnim);
    if (reduce) { shownRatio = to; paintRing(to); return; }
    var start = null;
    function step(ts) {
      if (start === null) start = ts;
      var t = Math.min(1, (ts - start) / RING_FILL_DURATION_MS);
      var e = easeOutCubic(t);
      var v = from + (to - from) * e;
      shownRatio = v;
      paintRing(v);
      if (t < 1) { ringAnim = requestAnimationFrame(step); } else { ringAnim = null; }
    }
    ringAnim = requestAnimationFrame(step);
  }

  function paintStatus() {
    status.textContent = '처리 ' + processed + '/' + TOTAL + ' · ' + Math.round((processed / TOTAL) * 100) + '%';
  }

  function addProcessed() {
    if (processed >= TOTAL) { paintStatus(); return; }
    var step = 1 + Math.floor(rand() * 3);
    processed = Math.min(TOTAL, processed + step);
    tweenRing(shownRatio, processed / TOTAL);
    paintStatus();
  }

  function resetAll() {
    processed = 0;
    shownRatio = 0;
    paintRing(0);
    paintStatus();
  }

  var processBtn = document.getElementById('wprProcess');
  var resetBtn = document.getElementById('wprReset');

  function onProcess() { root.classList.remove('is-demo'); addProcessed(); }
  function onReset() { root.classList.remove('is-demo'); resetAll(); }

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

  var demoSchedule = [200, 1200];
  var demoIndex = 0;
  var t0 = null;

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

  paintRing(0);
  paintStatus();
  requestAnimationFrame(tick);
})();

// WaitingQueueProgressRingCompletionRatio — vanilla 판(03-waiting-queue-progress-ring-completion-ratio) 의
// React 포트. 처리 인원 / 전체 인원 비율을 다시 계산해 stroke-dashoffset 으로 링을 채우고,
// 비율 구간(0~1/3, 1/3~2/3, 2/3~1)마다 링 색을 계산해 함께 바꾼다.
import { useEffect, useRef, useState } from "react";
import styles from "./WaitingQueueProgressRingCompletionRatio.module.scss";

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

const RING_FILL_DURATION_MS = 500;
const TOTAL = 30;
const RADIUS = 52;
const CIRCUMFERENCE = 2 * Math.PI * RADIUS;

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

function easeOutCubic(t: number): number { return 1 - Math.pow(1 - t, 3); }

function stageOf(ratio: number): string {
  if (ratio >= 2 / 3) return styles.isLate;
  if (ratio >= 1 / 3) return styles.isMid;
  return styles.isEarly;
}

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 WaitingQueueProgressRingCompletionRatio() {
  const [offset, setOffset] = useState(CIRCUMFERENCE);
  const [stageClass, setStageClass] = useState("");
  const [pctText, setPctText] = useState("0%");
  const [status, setStatus] = useState("");
  const [reduce, setReduce] = useState(false);
  const randRef = useRef<() => number>(seedRand(434031)) as Box<() => number>;
  const processedRef = useRef<number>(0) as Box<number>;
  const shownRatioRef = useRef<number>(0) as Box<number>;
  const ringAnimRef = 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 ringWrapRef = useRef<HTMLDivElement | null>(null) as Box<HTMLDivElement | null>;

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

  function paintRing(ratio: number): void {
    setOffset(CIRCUMFERENCE * (1 - ratio));
    setStageClass(stageOf(ratio));
    setPctText(Math.round(ratio * 100) + "%");
  }

  function paintStatus(): void {
    setStatus("처리 " + processedRef.current + "/" + TOTAL + " · " + Math.round((processedRef.current / TOTAL) * 100) + "%");
  }

  function tweenRing(from: number, to: number): void {
    flash(ringWrapRef.current, styles.isFlash, reduce);
    if (ringAnimRef.current) cancelAnimationFrame(ringAnimRef.current);
    if (reduce) { shownRatioRef.current = to; paintRing(to); return; }
    let start = 0;
    function step(ts: number): void {
      if (start === 0) start = ts;
      const t = Math.min(1, (ts - start) / RING_FILL_DURATION_MS);
      const e = easeOutCubic(t);
      const v = from + (to - from) * e;
      shownRatioRef.current = v;
      paintRing(v);
      if (t < 1) { ringAnimRef.current = requestAnimationFrame(step); } else { ringAnimRef.current = 0; }
    }
    ringAnimRef.current = requestAnimationFrame(step);
  }

  function addProcessed(): void {
    if (processedRef.current >= TOTAL) { paintStatus(); return; }
    const step = 1 + Math.floor(randRef.current() * 3);
    processedRef.current = Math.min(TOTAL, processedRef.current + step);
    tweenRing(shownRatioRef.current, processedRef.current / TOTAL);
    paintStatus();
  }

  function resetAll(): void {
    processedRef.current = 0;
    shownRatioRef.current = 0;
    paintRing(0);
    paintStatus();
  }

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

  useEffect(() => {
    paintRing(0);
    paintStatus();
    let t0 = 0;
    function tick(ts: number): void {
      if (t0 === 0) t0 = ts;
      const now = ts - t0;
      const sched = demoScheduleRef.current;
      if (!reduce && demoRef.current && demoIndexRef.current < sched.length && now >= sched[demoIndexRef.current]) {
        if (processedRef.current >= TOTAL) { resetAll(); } else { addProcessed(); }
        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 onProcess(): void { stopDemo(); addProcessed(); }
  function onReset(): void { stopDemo(); resetAll(); }

  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.wpr}>
        <div className={styles.ringWrap} ref={ringWrapRef}>
          <svg className={styles.ring} viewBox="0 0 120 120" aria-hidden="true">
            <circle className={styles.track} cx="60" cy="60" r="52" />
            <circle
              className={[styles.fill, stageClass].join(" ")}
              cx="60" cy="60" r="52"
              style={{ strokeDasharray: CIRCUMFERENCE.toFixed(2), strokeDashoffset: offset.toFixed(2) }}
            />
          </svg>
          <div className={styles.pct} aria-hidden="true">{pctText}</div>
        </div>
        <p className={styles.status} aria-live="polite">{status}</p>
        <div className={styles.controls}>
          <button type="button" className={[styles.btn, styles.btnPrimary].join(" ")} onClick={onProcess} onKeyDown={(e: { key: string; preventDefault: () => void }) => onKeyDown(e, onProcess)}>처리 추가</button>
          <button type="button" className={styles.btn} onClick={onReset} onKeyDown={(e: { key: string; preventDefault: () => void }) => onKeyDown(e, onReset)}>초기화</button>
        </div>
      </div>
    </main>
  );
}