01リアルタイム視聴カウンター

<main class="stage is-demo">
  <section class="lv" aria-label="リアルタイム視聴者数">
    <div class="lv__left">
      <p class="lv__head">
        <span class="lv__ic" aria-hidden="true"><svg viewBox="0 0 256 256" width="20" height="20"><g fill="currentColor"><path d="M136 108a52 52 0 1 1-52-52a52 52 0 0 1 52 52" opacity=".2"/><path d="M117.25 157.92a60 60 0 1 0-66.5 0a95.83 95.83 0 0 0-47.22 37.71a8 8 0 1 0 13.4 8.74a80 80 0 0 1 134.14 0a8 8 0 0 0 13.4-8.74a95.83 95.83 0 0 0-47.22-37.71M40 108a44 44 0 1 1 44 44a44.05 44.05 0 0 1-44-44m210.14 98.7a8 8 0 0 1-11.07-2.33A79.83 79.83 0 0 0 172 168a8 8 0 0 1 0-16a44 44 0 1 0-16.34-84.87a8 8 0 1 1-5.94-14.85a60 60 0 0 1 55.53 105.64a95.83 95.83 0 0 1 47.22 37.71a8 8 0 0 1-2.33 11.07"/></g></svg></span>
        <span class="lv__live"><span class="lv__dot" aria-hidden="true"></span>ライブ</span>
      </p>
      <p class="lv__count">いま <b class="lv__n" id="lv-n">128</b>人が視聴中</p>
      <p class="lv__st" id="lv-st" role="status" aria-live="polite">このページを同時に見ている人数です</p>
    </div>
    <div class="lv__bars" aria-hidden="true">
      <span class="lv__bar" style="--i:0;--v:.42"><i></i></span>
      <span class="lv__bar" style="--i:1;--v:.60"><i></i></span>
      <span class="lv__bar" style="--i:2;--v:.48"><i></i></span>
      <span class="lv__bar" style="--i:3;--v:.82"><i></i></span>
      <span class="lv__bar" style="--i:4;--v:.55"><i></i></span>
      <span class="lv__bar" style="--i:5;--v:.70"><i></i></span>
      <span class="lv__bar" style="--i:6;--v:.92"><i></i></span>
    </div>
  </section>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;
$easing: $ease-pop;
$color: $subject-blue;

@include stage($stage-ink);

.lv {
  box-sizing: border-box; width: min(360px, 94vw);
  display: flex; align-items: flex-end; gap: $sp-5;
  background: $subject-cream; color: $subject-ink;
  border-radius: $r-card; padding: $sp-4; box-shadow: $shadow-raised;
}

.lv__left { flex: 1 1 auto; min-width: 0; }

.lv__head { display: flex; align-items: center; gap: $sp-2; margin: 0; }
.lv__ic { display: inline-flex; color: $color; }

.lv__live {
  display: inline-flex; align-items: center; gap: $sp-1;
  padding: $sp-1 $sp-2; border-radius: $r-pill;
  background: $stage-paper; color: $error;   // 크림 카드 위 붉은 틴트 면은 4.31:1 — 페이퍼 면 위 $error 5.47:1
  font-weight: 800; font-size: 10px; line-height: 1.2;
}
.lv__dot {
  width: 6px; height: 6px; border-radius: 50%; background: $error;
  animation-name: lv-pulse; animation-duration: $duration; animation-timing-function: $ease-out;
  animation-iteration-count: infinite;
}
@keyframes lv-pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50%      { transform: scale(1.6); opacity: .45; }
}

.lv__count { margin: $sp-2 0 0; font-weight: 700; font-size: 13px; line-height: 1.2; }
.lv__n {
  font-weight: 800; font-size: 44px; line-height: 1.05;
  font-variant-numeric: tabular-nums; color: $color;
}

.lv__st { margin: $sp-1 0 0; font-weight: 500; font-size: 10px; line-height: 1.3; color: rgba(23, 20, 26, .6); }

// 막대 7칸 — 폭은 grid 가 균등 분배하고(BD19 오탐 회피), 높이는 scaleY 배율만 바꾼다
.lv__bars {
  flex: 0 0 auto; display: grid; grid-template-columns: repeat(7, 1fr);
  gap: $sp-2; width: 132px; height: 72px;
}
.lv__bar { display: flex; align-items: flex-end; justify-content: center; }
.lv__bar i {
  display: block; width: 12px; height: 100%; border-radius: $r-xs; background: $color;
  transform: scaleY(var(--v, .5)); transform-origin: bottom; // 규칙8: 아래서 차오름
  transition: transform $dur-base $ease-out;
}

// ── 측정용 자동 루프 ────────────────────────────────
// 손대기 전에도 막대가 물결치게 — 사람이 누르거나 키를 치면 JS 가 .is-demo 를 뗀다
.stage.is-demo .lv__bar i {
  animation-name: lv-wave;
  animation-duration: $duration;
  animation-timing-function: $ease-out;
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: calc(var(--i) * 90ms);
}
@keyframes lv-wave {
  0%, 100% { transform: scaleY(.34); }
  35%      { transform: scaleY(1); }
  70%      { transform: scaleY(.58); }
}

// ── 접근성 ──────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .lv__dot, .stage.is-demo .lv__bar i, .lv__bar i {
    animation: none !important;
    transition: none !important;
  }
  .stage.is-demo .lv__bar i { transform: scaleY(var(--v, .5)) !important; }
}

// ── 반응형(320×200) ──────────────────────────────────
@media (max-width: 340px), (max-height: 220px) {
  .lv { width: min(292px, 92vw); gap: $sp-3; padding: $sp-3; }
  .lv__head { gap: $sp-1; }
  .lv__ic svg { width: 14px; height: 14px; }
  .lv__live { padding: 0 $sp-1; font-size: 9px; }
  .lv__count { margin-top: $sp-1; font-size: 11px; }
  .lv__n { font-size: 28px; }
  .lv__st { margin-top: 0; font-size: 9px; }
  .lv__bars { gap: $sp-1; width: 80px; height: 46px; }
  .lv__bar i { width: 8px; }
}

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);
}

.lv {
  box-sizing: border-box;
  width: min(360px, 94vw);
  display: flex;
  align-items: flex-end;
  gap: 20px;
  background: #fff7e6;
  color: #17141a;
  border-radius: 16px;
  padding: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.lv__left {
  flex: 1 1 auto;
  min-width: 0;
}

.lv__head {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
}

.lv__ic {
  display: inline-flex;
  color: #2f6df6;
}

.lv__live {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 8px;
  border-radius: 999px;
  background: #ffffff;
  color: #c2361a;
  font-weight: 800;
  font-size: 10px;
  line-height: 1.2;
}

.lv__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #c2361a;
  animation-name: lv-pulse;
  animation-duration: 2s;
  animation-timing-function: ease-out;
  animation-iteration-count: infinite;
}

@keyframes lv-pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.6);
    opacity: 0.45;
  }
}
.lv__count {
  margin: 8px 0 0;
  font-weight: 700;
  font-size: 13px;
  line-height: 1.2;
}

.lv__n {
  font-weight: 800;
  font-size: 44px;
  line-height: 1.05;
  font-variant-numeric: tabular-nums;
  color: #2f6df6;
}

.lv__st {
  margin: 4px 0 0;
  font-weight: 500;
  font-size: 10px;
  line-height: 1.3;
  color: rgba(23, 20, 26, 0.6);
}

.lv__bars {
  flex: 0 0 auto;
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 8px;
  width: 132px;
  height: 72px;
}

.lv__bar {
  display: flex;
  align-items: flex-end;
  justify-content: center;
}

.lv__bar i {
  display: block;
  width: 12px;
  height: 100%;
  border-radius: 4px;
  background: #2f6df6;
  transform: scaleY(var(--v, 0.5));
  transform-origin: bottom;
  transition: transform 300ms ease-out;
}

.stage.is-demo .lv__bar i {
  animation-name: lv-wave;
  animation-duration: 2s;
  animation-timing-function: ease-out;
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: calc(var(--i) * 90ms);
}

@keyframes lv-wave {
  0%, 100% {
    transform: scaleY(0.34);
  }
  35% {
    transform: scaleY(1);
  }
  70% {
    transform: scaleY(0.58);
  }
}
@media (prefers-reduced-motion: reduce) {
  .lv__dot, .stage.is-demo .lv__bar i, .lv__bar i {
    animation: none !important;
    transition: none !important;
  }
  .stage.is-demo .lv__bar i {
    transform: scaleY(var(--v, 0.5)) !important;
  }
}
@media (max-width: 340px), (max-height: 220px) {
  .lv {
    width: min(292px, 92vw);
    gap: 12px;
    padding: 12px;
  }
  .lv__head {
    gap: 4px;
  }
  .lv__ic svg {
    width: 14px;
    height: 14px;
  }
  .lv__live {
    padding: 0 4px;
    font-size: 9px;
  }
  .lv__count {
    margin-top: 4px;
    font-size: 11px;
  }
  .lv__n {
    font-size: 28px;
  }
  .lv__st {
    margin-top: 0;
    font-size: 9px;
  }
  .lv__bars {
    gap: 4px;
    width: 80px;
    height: 46px;
  }
  .lv__bar i {
    width: 8px;
  }
}

// 실제 동작: setInterval 이 1.2초마다 시청자 수를 ±1~6 랜덤 워크(96~168)로 옮기고, 그 값을 막대 7칸의
// --v(=scaleY 배율)에 큐처럼 밀어 넣는다. 읽어 주는 문장은 5번에 한 번만 갱신해 화면낭독기가 쉴 새 없이 떠들지 않게 한다.
var stage = document.querySelector('.stage');
var count = document.getElementById('lv-n');
var msg = document.getElementById('lv-st');
var bars = [].slice.call(document.querySelectorAll('.lv__bar'));
var n = 128, ticks = 0;
var history = [.42, .60, .48, .82, .55, .70, .92];
function paint() {
  count.textContent = n;
  for (var i = 0; i < bars.length; i++) bars[i].style.setProperty('--v', history[i].toFixed(2));
}
function step() {
  var d = Math.floor(Math.random() * 6) + 1;
  if (Math.random() < .5) d = -d;
  n = Math.max(96, Math.min(168, n + d));
  history.push(Math.max(.28, Math.min(1, (n - 88) / 84)));
  history.shift();
  paint();
  ticks++;
  if (ticks % 5 === 0) msg.textContent = 'いま ' + n + '人がこのページを見ています';
}
setInterval(step, 1200);
function human() { stage.classList.remove('is-demo'); }
stage.addEventListener('pointerdown', human, { once: true });
window.addEventListener('keydown', human, { once: true });

import { useEffect, useState } from "react";
import type { CSSProperties } from "react";
import styles from "./LiveViewerCounter.module.scss";

export type LiveViewerCounterProps = {
  /** 격자 미리보기용 루프 길이(ms) */
  duration?: number;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type BarVars = CSSProperties & { "--i"?: number; "--v"?: number };

const initialBars = [0.42, 0.6, 0.48, 0.82, 0.55, 0.7, 0.92];

function Users() {
  return (
    <svg viewBox="0 0 256 256" width="20" height="20" aria-hidden="true">
      <g fill="currentColor">
        <path d="M136 108a52 52 0 1 1-52-52a52 52 0 0 1 52 52" opacity=".2" />
        <path d="M117.25 157.92a60 60 0 1 0-66.5 0a95.83 95.83 0 0 0-47.22 37.71a8 8 0 1 0 13.4 8.74a80 80 0 0 1 134.14 0a8 8 0 0 0 13.4-8.74a95.83 95.83 0 0 0-47.22-37.71M40 108a44 44 0 1 1 44 44a44.05 44.05 0 0 1-44-44m210.14 98.7a8 8 0 0 1-11.07-2.33A79.83 79.83 0 0 0 172 168a8 8 0 0 1 0-16a44 44 0 1 0-16.34-84.87a8 8 0 1 1-5.94-14.85a60 60 0 0 1 55.53 105.64a95.83 95.83 0 0 1 47.22 37.71a8 8 0 0 1-2.33 11.07" />
      </g>
    </svg>
  );
}

export default function LiveViewerCounter({
  duration = 2000,
  easing = "cubic-bezier(.2,1.4,.4,1)",
  color = "#2f6df6",
}: LiveViewerCounterProps) {
  const [n, setN] = useState(128);
  const [bars, setBars] = useState<number[]>(initialBars);
  const [msg, setMsg] = useState("이 페이지를 함께 보는 사람 수예요");
  const [loop, setLoop] = useState(true);

  // setInterval 이 1.2초마다 값을 ±1~6 옮기고(96~168), 그 값을 막대 7칸의 --v(=scaleY 배율)로 밀어 넣는다.
  // 읽어 주는 문장은 5번에 한 번만 갱신해 화면낭독기가 쉴 새 없이 떠들지 않게 한다.
  useEffect(() => {
    let count = 128;
    let tick = 0;
    let history = initialBars.slice();
    const id = setInterval(() => {
      let d = Math.floor(Math.random() * 6) + 1;
      if (Math.random() < 0.5) d = -d;
      count = Math.max(96, Math.min(168, count + d));
      history = history.slice(1).concat(Math.max(0.28, Math.min(1, (count - 88) / 84)));
      tick += 1;
      setN(count);
      setBars(history);
      if (tick % 5 === 0) setMsg(`지금 ${count}명이 이 페이지를 보고 있어요`);
    }, 1200);
    return () => clearInterval(id);
  }, []);

  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  const cls = [styles.lv, loop ? styles["is-demo"] : ""].filter(Boolean).join(" ");

  return (
    <section
      className={cls}
      style={vars}
      aria-label="실시간 시청자 수"
      onPointerDown={() => setLoop(false)}
      onKeyDown={() => setLoop(false)}
    >
      <div className={styles.lv__left}>
        <p className={styles.lv__head}>
          <span className={styles.lv__ic} aria-hidden="true"><Users /></span>
          <span className={styles.lv__live}>
            <span className={styles.lv__dot} aria-hidden="true" />
            실시간
          </span>
        </p>
        <p className={styles.lv__count}>
          지금 <b className={styles.lv__n}>{n}</b>명 보는 중
        </p>
        <p className={styles.lv__st} role="status" aria-live="polite">{msg}</p>
      </div>
      <div className={styles.lv__bars} aria-hidden="true">
        {bars.map((v, i) => {
          const bv: BarVars = { "--i": i, "--v": v };
          return (
            <span key={i} className={styles.lv__bar} style={bv}>
              <i />
            </span>
          );
        })}
      </div>
    </section>
  );
}