06Drag-to-confirm — a button that reaches a confirmed state once a dragged position value passes a threshold

<main class="stage">
<div class="ctadcs is-demo" id="ctadcs">
  <div class="ctadcs__panel">
    <div class="ctadcs__track" id="ctadcsTrack">
      <span class="ctadcs__trackLabel">Slide to confirm payment</span>
      <button class="ctadcs__thumb" id="ctadcsThumb" type="button" aria-label="Slide to confirm"></button>
    </div>
    <span class="ctadcs__hint" id="ctadcsHint">Must pass the 70% threshold to confirm</span>
  </div>
</div>
</main>

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

// 계산 겹(임계 판정·스프링 복귀)은 JS 에 있다 — 여기는 정적 배치만.
@include stage($stage-yellow);

.stage { position: relative; }

.ctadcs__panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
  padding: $sp-5;
  border-radius: $r-card;
  background: $stage-paper;
}

.ctadcs__track {
  position: relative;
  width: 220px;
  height: 48px;
  border-radius: $r-pill;
  background: $subject-cream;
  display: flex;
  align-items: center;
  padding: $sp-1;
}

.ctadcs__trackLabel {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: rgba($subject-ink, .5);
  font-size: 13px;
  font-weight: 700;
  pointer-events: none;
}

.ctadcs__thumb {
  position: relative;
  width: 40px;
  height: 40px;
  border: 0;
  border-radius: $r-pill;
  background: $subject-blue-deep;
  cursor: grab;
  touch-action: none;
}

.ctadcs__hint {
  color: rgba($subject-ink, .72);
  font-size: 12px;
  text-align: center;
}

@media (max-width: 340px) {
  .ctadcs__panel { padding: $sp-4; gap: $sp-2; }
  .ctadcs__track { width: 180px; height: 44px; }
  .ctadcs__thumb { width: 36px; height: 36px; }
}

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

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);
}

.stage {
  position: relative;
}

.ctadcs__panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 20px;
  border-radius: 16px;
  background: #ffffff;
}

.ctadcs__track {
  position: relative;
  width: 220px;
  height: 48px;
  border-radius: 999px;
  background: #fff7e6;
  display: flex;
  align-items: center;
  padding: 4px;
}

.ctadcs__trackLabel {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: rgba(23, 20, 26, 0.5);
  font-size: 13px;
  font-weight: 700;
  pointer-events: none;
}

.ctadcs__thumb {
  position: relative;
  width: 40px;
  height: 40px;
  border: 0;
  border-radius: 999px;
  background: #0a4fe8;
  cursor: grab;
  touch-action: none;
}

.ctadcs__hint {
  color: rgba(23, 20, 26, 0.72);
  font-size: 12px;
  text-align: center;
}

@media (max-width: 340px) {
  .ctadcs__panel {
    padding: 16px;
    gap: 8px;
  }
  .ctadcs__track {
    width: 180px;
    height: 44px;
  }
  .ctadcs__thumb {
    width: 36px;
    height: 36px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ctadcs__thumb {
    transition: none !important;
  }
}

(function () {
  var root = document.getElementById('ctadcs');
  var track = document.getElementById('ctadcsTrack');
  var thumb = document.getElementById('ctadcsThumb');
  var hint = document.getElementById('ctadcsHint');

  // 계산 겹: 끄는 위치 값을 트랙 폭 대비 비율(0~1)로 clamp 하고, THRESH(0.7)를 넘겼는지로
  // 확정 여부를 가른다. 기준 미달로 놓이면 목표(0)까지 매 프레임 lerp(관성 없는 스프링 복귀)한다.
  var THRESH = 0.7;
  var pos = 0, target = 0, raf = null, confirmed = false;
  var THUMB_W = 40;

  function maxTravel() { return track.clientWidth - THUMB_W - 8; }

  function apply(p) {
    var mt = maxTravel();
    thumb.style.transform = 'translateX(' + (p * mt).toFixed(1) + 'px)';
  }

  function settle() {
    var diff = target - pos;
    pos += diff * 0.3;
    if (Math.abs(diff) < 0.002) { pos = target; }
    apply(pos);
    if (Math.abs(target - pos) > 0.002) {
      raf = requestAnimationFrame(settle);
    } else {
      raf = null;
    }
  }
  function goTo(p) {
    target = p;
    if (raf === null) { raf = requestAnimationFrame(settle); }
  }

  function release(p) {
    if (p >= THRESH) {
      confirmed = true;
      goTo(1);
      hint.textContent = 'Confirmed';
      setTimeout(function () { confirmed = false; goTo(0); hint.textContent = 'Must pass the 70% threshold to confirm'; }, 500);
    } else {
      goTo(0);
    }
  }

  var dragging = false, startX = 0, startPos = 0;
  function onDown(clientX) {
    if (confirmed) { return; }
    dragging = true; startX = clientX; startPos = pos;
    if (raf) { cancelAnimationFrame(raf); raf = null; }
  }
  function onMove(clientX) {
    if (!dragging) { return; }
    var mt = maxTravel();
    var dp = (clientX - startX) / mt;
    pos = Math.max(0, Math.min(1, startPos + dp));
    apply(pos);
  }
  function onUp() {
    if (!dragging) { return; }
    dragging = false;
    release(pos);
  }

  function wireReal() {
    thumb.addEventListener('pointerdown', function (e) { root.classList.remove('is-demo'); stopAutoplay(); onDown(e.clientX); });
    window.addEventListener('pointermove', function (e) { onMove(e.clientX); });
    window.addEventListener('pointerup', onUp);
  }
  wireReal();
  apply(0);

  // 자동 루프: 실제 드래그 대신 목표 값을 단계적으로 옮겨 같은 release() 판정 로직을 탄다.
  var autoTarget = 0, autoTimer = null;
  function autoTick() {
    autoTarget = autoTarget >= 1 ? 0 : Math.min(1, autoTarget + 0.35);
    pos = autoTarget;
    apply(pos);
    if (autoTarget >= 1) { release(1); }
  }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } }
  if (!reduce) { autoTimer = setInterval(autoTick, 220); }
})();

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

export type CtaBtnDragConfirmSlideProps = {
  color?: string;
};

export default function CtaBtnDragConfirmSlide({
  color = "#0a4fe8",
}: CtaBtnDragConfirmSlideProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const track = root.querySelector<HTMLDivElement>(`.${styles.track}`);
    const thumb = root.querySelector<HTMLButtonElement>(`.${styles.thumb}`);
    const hint = root.querySelector<HTMLSpanElement>(`.${styles.hint}`);
    if (!track || !thumb || !hint) return;

    // 계산 겹: 끄는 위치 값을 트랙 폭 대비 비율(0~1)로 clamp 하고, THRESH(0.7)를 넘겼는지로
    // 확정 여부를 가른다. 기준 미달로 놓이면 목표(0)까지 매 프레임 lerp(스프링 복귀)한다.
    const THRESH = 0.7;
    const THUMB_W = 40;
    let pos = 0, target = 0, raf: number | null = null, confirmed = false;

    function maxTravel() { return track!.clientWidth - THUMB_W - 8; }
    function apply(p: number) {
      const mt = maxTravel();
      thumb!.style.transform = "translateX(" + (p * mt).toFixed(1) + "px)";
    }
    function settle() {
      const diff = target - pos;
      pos += diff * 0.3;
      if (Math.abs(diff) < 0.002) { pos = target; }
      apply(pos);
      raf = Math.abs(target - pos) > 0.002 ? requestAnimationFrame(settle) : null;
    }
    function goTo(p: number) {
      target = p;
      if (raf === null) { raf = requestAnimationFrame(settle); }
    }
    function release(p: number) {
      if (p >= THRESH) {
        confirmed = true;
        goTo(1);
        hint!.textContent = "확정되었습니다";
        window.setTimeout(() => { confirmed = false; goTo(0); hint!.textContent = "기준(70%)을 넘겨야 확정됩니다"; }, 500);
      } else {
        goTo(0);
      }
    }

    let dragging = false, startX = 0, startPos = 0;
    function onDown(clientX: number) {
      if (confirmed) return;
      dragging = true; startX = clientX; startPos = pos;
      if (raf !== null) { cancelAnimationFrame(raf); raf = null; }
    }
    function onMove(clientX: number) {
      if (!dragging) return;
      const mt = maxTravel();
      const dp = (clientX - startX) / mt;
      pos = Math.max(0, Math.min(1, startPos + dp));
      apply(pos);
    }
    function onUp() {
      if (!dragging) return;
      dragging = false;
      release(pos);
    }

    function onPointerDown(e: PointerEvent) { stopAutoplay(); onDown(e.clientX); }
    function onPointerMove(e: PointerEvent) { onMove(e.clientX); }
    thumb.addEventListener("pointerdown", onPointerDown);
    window.addEventListener("pointermove", onPointerMove);
    window.addEventListener("pointerup", onUp);
    apply(0);

    let autoTarget = 0, autoTimer: number | null = null;
    function autoTick() {
      autoTarget = autoTarget >= 1 ? 0 : Math.min(1, autoTarget + 0.35);
      pos = autoTarget;
      apply(pos);
      if (autoTarget >= 1) { release(1); }
    }
    function stopAutoplay() { if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; } }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { autoTimer = window.setInterval(autoTick, 220); }

    return () => {
      stopAutoplay();
      if (raf !== null) { cancelAnimationFrame(raf); }
      thumb.removeEventListener("pointerdown", onPointerDown);
      window.removeEventListener("pointermove", onPointerMove);
      window.removeEventListener("pointerup", onUp);
    };
  }, []);

  return (
    <div ref={rootRef} className={styles.stage}>
      <div className={styles.panel}>
        <div className={styles.track}>
          <span className={styles.trackLabel}>밀어서 결제 확정</span>
          <button className={styles.thumb} type="button" aria-label="밀어서 확정" style={{ background: color }} />
        </div>
        <span className={styles.hint}>기준(70%)을 넘겨야 확정됩니다</span>
      </div>
    </div>
  );
}