02글자 수 채움 — 복사된 글자 수만큼 표시가 차오르는 버튼

<main class="stage">
<section class="panel">
  <div class="card">
    <p class="preview" id="preview">이 문구는 초대장 카드 아래 자동으로 채워지는 안내용 예시 텍스트입니다.</p>
    <button class="copyBtn" id="copyBtn" type="button" aria-label="문구 복사">
      <span class="fillTrack" aria-hidden="true"><span class="fillBar" id="fillBar"></span></span>
      <span class="iconSlot">
        <svg class="icon" id="icon" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M232 56v144a16 16 0 0 1-16 16H40a16 16 0 0 1-16-16V56a16 16 0 0 1 16-16h176a16 16 0 0 1 16 16" opacity=".2"/><path d="m205.66 85.66l-96 96a8 8 0 0 1-11.32 0l-40-40a8 8 0 0 1 11.32-11.32L104 164.69l90.34-90.35a8 8 0 0 1 11.32 11.32"/></g></svg>
      </span>
      <span class="count" id="count">0</span>
    </button>
  </div>
  <span class="sr" id="live" role="status" aria-live="polite"></span>
</section>
</main>

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

@include stage($stage-yellow);

.panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-4;
}

.card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-4;
  background: $subject-cream;
  border-radius: $r-card;
  padding: $sp-5 $sp-6;
  box-shadow: $shadow-raised;
  max-width: 380px;
}

.preview {
  margin: 0;
  color: $subject-ink;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 500;
  font-size: 13px;
  line-height: 1.5;
  text-align: center;
}

.copyBtn {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: $sp-2;
  padding: $sp-3 $sp-5;
  border: 0;
  border-radius: $r-pill;
  background: $subject-ink;
  color: $subject-cream;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 600;
  font-size: 14px;
  line-height: 1.3;
  cursor: pointer;
  overflow: hidden;
  isolation: isolate;
}

.fillTrack {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.fillBar {
  --fill: 0;
  position: absolute;
  inset: 0;
  transform: scaleX(var(--fill));
  transform-origin: left center;
  background: $subject-blue-deep;
}

.iconSlot {
  position: relative;
  z-index: 1;
  width: 18px;
  height: 18px;
  flex: none;
}

.icon {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
}

.count {
  position: relative;
  z-index: 1;
  min-width: 1.4em;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 340px) {
  .card {
    padding: $sp-4 $sp-5;
  }
  .preview {
    font-size: 12px;
  }
}

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

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  background: #fff7e6;
  border-radius: 16px;
  padding: 20px 24px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  max-width: 380px;
}

.preview {
  margin: 0;
  color: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 500;
  font-size: 13px;
  line-height: 1.5;
  text-align: center;
}

.copyBtn {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border: 0;
  border-radius: 999px;
  background: #17141a;
  color: #fff7e6;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  font-weight: 600;
  font-size: 14px;
  line-height: 1.3;
  cursor: pointer;
  overflow: hidden;
  isolation: isolate;
}

.fillTrack {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.fillBar {
  --fill: 0;
  position: absolute;
  inset: 0;
  transform: scaleX(var(--fill));
  transform-origin: left center;
  background: #0a4fe8;
}

.iconSlot {
  position: relative;
  z-index: 1;
  width: 18px;
  height: 18px;
  flex: none;
}

.icon {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
}

.count {
  position: relative;
  z-index: 1;
  min-width: 1.4em;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.sr {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 340px) {
  .card {
    padding: 16px 20px;
  }
  .preview {
    font-size: 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .copyBtn * {
    transition: none;
  }
}

// 글자 수 채움 — 복사한 문장의 글자 수(preview 실측 length)를 채움 비율로 바꾸고,
// 채움이 끝나면 아이콘·숫자가 짧게 떠올랐다 정착한다(translateY 보간, 이차 감쇠).
// 계산 겹: 글자 수 실측 → 진행률 → 오프셋(--fill) 재계산. 실사용자 리스너 있음(버튼 클릭).
// 실 클립보드 API 호출 없음 — 상태는 전부 시뮬레이션.
(function () {
  var preview = document.getElementById('preview');
  var btn = document.getElementById('copyBtn');
  var fillBar = document.getElementById('fillBar');
  var icon = document.getElementById('icon');
  var count = document.getElementById('count');
  var live = document.getElementById('live');
  if (!preview || !btn || !fillBar || !icon || !count || !live) return;

  var CHAR_COUNT = preview.textContent.trim().length;
  var FILL_MS_PER_CHAR = 18;
  var FILL_MS = CHAR_COUNT * FILL_MS_PER_CHAR;
  var BOUNCE_MS = 260;
  var IDLE_MS = 140;

  function bounceEase(p) {
    if (p < 0.5) return p / 0.5;
    var q = (p - 0.5) / 0.5;
    return 1 - q * q;
  }

  function render(ratio, lift) {
    fillBar.style.setProperty('--fill', ratio.toFixed(4));
    count.textContent = String(Math.round(ratio * CHAR_COUNT));
    icon.style.opacity = ratio >= 1 ? '1' : '0';
    var y = -lift * 6;
    var t = 'translateY(' + y.toFixed(2) + 'px)';
    icon.style.transform = t;
    count.style.transform = t;
  }

  function sequence(t) {
    if (t < FILL_MS) {
      render(t / FILL_MS, 0);
      live.textContent = '';
    } else if (t < FILL_MS + BOUNCE_MS) {
      render(1, bounceEase((t - FILL_MS) / BOUNCE_MS));
      live.textContent = CHAR_COUNT + '자 복사됨';
    } else {
      render(1, 0);
      live.textContent = CHAR_COUNT + '자 복사됨';
    }
  }

  render(0, 0);

  var CYCLE_MS = 2000;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var autoStart = null;
  var autoRaf = 0;

  function autoLoop(ts) {
    if (autoStart === null) autoStart = ts;
    var t = (ts - autoStart) % CYCLE_MS;
    if (t < IDLE_MS) { render(0, 0); live.textContent = ''; }
    else sequence(t - IDLE_MS);
    autoRaf = requestAnimationFrame(autoLoop);
  }

  if (!reduce) autoRaf = requestAnimationFrame(autoLoop);

  btn.addEventListener('click', function () {
    if (autoRaf) { cancelAnimationFrame(autoRaf); autoRaf = 0; }
    render(0, 0);
    var clickStart = null;
    function userLoop(ts) {
      if (clickStart === null) clickStart = ts;
      var t = ts - clickStart;
      sequence(t);
      if (t < FILL_MS + BOUNCE_MS + 20) requestAnimationFrame(userLoop);
    }
    requestAnimationFrame(userLoop);
  });
})();

import { useEffect, useRef } from "react";
import styles from "./CopyCharCountFill.module.scss";

// 글자 수 채움 — 복사한 문장의 글자 수(preview 실측 length)를 채움 비율로 바꾸고,
// 채움이 끝나면 아이콘·숫자가 짧게 떠올랐다 정착한다(translateY 보간, 이차 감쇠).
// 계산 겹: 글자 수 실측 → 진행률 → 오프셋(--fill) 재계산. 실사용자 리스너 있음(버튼 클릭).
// 실 클립보드 API 호출 없음 — 상태는 전부 시뮬레이션.
const FILL_MS_PER_CHAR = 18;
const BOUNCE_MS = 260;
const IDLE_MS = 140;
const CYCLE_MS = 2000;
const PREVIEW_TEXT = "이 문구는 초대장 카드 아래 자동으로 채워지는 안내용 예시 텍스트입니다.";

function bounceEase(p: number) {
  if (p < 0.5) return p / 0.5;
  const q = (p - 0.5) / 0.5;
  return 1 - q * q;
}

export default function CopyCharCountFill() {
  const fillBarRef = useRef<HTMLSpanElement>(null);
  const iconRef = useRef<SVGSVGElement>(null);
  const countRef = useRef<HTMLSpanElement>(null);
  const liveRef = useRef<HTMLSpanElement>(null);
  const btnRef = useRef<HTMLButtonElement>(null);

  useEffect(() => {
    const fillBar = fillBarRef.current;
    const icon = iconRef.current;
    const count = countRef.current;
    const live = liveRef.current;
    const btn = btnRef.current;
    if (!fillBar || !icon || !count || !live || !btn) return;

    const CHAR_COUNT = PREVIEW_TEXT.trim().length;
    const FILL_MS = CHAR_COUNT * FILL_MS_PER_CHAR;

    function render(ratio: number, lift: number) {
      fillBar!.style.setProperty("--fill", ratio.toFixed(4));
      count!.textContent = String(Math.round(ratio * CHAR_COUNT));
      icon!.style.opacity = ratio >= 1 ? "1" : "0";
      const y = -lift * 6;
      const t = `translateY(${y.toFixed(2)}px)`;
      icon!.style.transform = t;
      count!.style.transform = t;
    }

    function sequence(t: number) {
      if (t < FILL_MS) {
        render(t / FILL_MS, 0);
        live!.textContent = "";
      } else if (t < FILL_MS + BOUNCE_MS) {
        render(1, bounceEase((t - FILL_MS) / BOUNCE_MS));
        live!.textContent = `${CHAR_COUNT}자 복사됨`;
      } else {
        render(1, 0);
        live!.textContent = `${CHAR_COUNT}자 복사됨`;
      }
    }

    render(0, 0);

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let autoStart: number | null = null;
    let autoRaf = 0;

    function autoLoop(ts: number) {
      if (autoStart === null) autoStart = ts;
      const t = (ts - autoStart) % CYCLE_MS;
      if (t < IDLE_MS) {
        render(0, 0);
        live!.textContent = "";
      } else {
        sequence(t - IDLE_MS);
      }
      autoRaf = requestAnimationFrame(autoLoop);
    }

    if (!reduce) autoRaf = requestAnimationFrame(autoLoop);

    function onClick() {
      if (autoRaf) {
        cancelAnimationFrame(autoRaf);
        autoRaf = 0;
      }
      render(0, 0);
      let clickStart: number | null = null;
      function userLoop(ts: number) {
        if (clickStart === null) clickStart = ts;
        const t = ts - clickStart;
        sequence(t);
        if (t < FILL_MS + BOUNCE_MS + 20) requestAnimationFrame(userLoop);
      }
      requestAnimationFrame(userLoop);
    }

    btn.addEventListener("click", onClick);
    return () => {
      if (autoRaf) cancelAnimationFrame(autoRaf);
      btn.removeEventListener("click", onClick);
    };
  }, []);

  return (
    <div className={styles.stage}>
      <section className={styles.panel}>
        <div className={styles.card}>
          <p className={styles.preview}>{PREVIEW_TEXT}</p>
          <button ref={btnRef} className={styles.copyBtn} type="button" aria-label="문구 복사">
            <span className={styles.fillTrack} aria-hidden="true">
              <span ref={fillBarRef} className={styles.fillBar} />
            </span>
            <span className={styles.iconSlot}>
              <svg ref={iconRef} className={styles.icon} viewBox="0 0 256 256" aria-hidden="true">
                <g fill="currentColor">
                  <path d="M232 56v144a16 16 0 0 1-16 16H40a16 16 0 0 1-16-16V56a16 16 0 0 1 16-16h176a16 16 0 0 1 16 16" opacity=".2" />
                  <path d="m205.66 85.66l-96 96a8 8 0 0 1-11.32 0l-40-40a8 8 0 0 1 11.32-11.32L104 164.69l90.34-90.35a8 8 0 0 1 11.32 11.32" />
                </g>
              </svg>
            </span>
            <span ref={countRef} className={styles.count}>0</span>
          </button>
        </div>
        <span ref={liveRef} className={styles.sr} role="status" aria-live="polite" />
      </section>
    </div>
  );
}