02Rotation bind — an indicator whose rotation value turns in proportion to the pulled distance ratio

<main class="stage">
<div class="prrb is-demo" id="prrb">
  <div class="prrb__phone" id="prrbPhone">
    <div class="prrb__zone">
      <span class="prrb__ring"></span>
      <span class="prrb__knob" id="prrbKnob"></span>
    </div>
    <div class="prrb__list" id="prrbList">
      <div class="prrb__row"></div>
      <div class="prrb__row"></div>
      <div class="prrb__row"></div>
    </div>
  </div>
  <span class="prrb__hint" id="prrbHint">Pull to refresh</span>
</div>
</main>

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

// 계산 겹(비율→각도 place())은 JS 에 있다 — 여기는 정적 배치만.
@include stage($stage-yellow);

.prrb {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
}

.prrb__phone {
  position: relative;
  width: 220px;
  height: 168px;
  overflow: hidden;
  border-radius: $r-card;
  background: $stage-paper;
  touch-action: none;
  cursor: grab;
}

.prrb__zone {
  position: relative;
  height: 56px;
  display: grid;
  place-items: center;
}

.prrb__ring {
  position: absolute;
  width: 36px;
  height: 36px;
  border-radius: $r-pill;
  border: 2px solid rgba($subject-ink, .16);
}

.prrb__knob {
  position: relative;
  width: 8px;
  height: 8px;
  border-radius: $r-pill;
  background: $subject-blue-deep;
}

.prrb__list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: $sp-2;
  padding: $sp-3 $sp-4;
}

.prrb__row {
  height: 20px;
  border-radius: $r-sm;
  background: $subject-cream;
}

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

@media (max-width: 340px) {
  .prrb__phone { width: 176px; height: 132px; }
  .prrb__zone { height: 44px; }
  .prrb__ring { width: 28px; height: 28px; }
  .prrb__list { padding: $sp-2 $sp-3; gap: $sp-1; }
  .prrb__row { height: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  .prrb__knob, .prrb__list { 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);
}

.prrb {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.prrb__phone {
  position: relative;
  width: 220px;
  height: 168px;
  overflow: hidden;
  border-radius: 16px;
  background: #ffffff;
  touch-action: none;
  cursor: grab;
}

.prrb__zone {
  position: relative;
  height: 56px;
  display: grid;
  place-items: center;
}

.prrb__ring {
  position: absolute;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  border: 2px solid rgba(23, 20, 26, 0.16);
}

.prrb__knob {
  position: relative;
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: #0a4fe8;
}

.prrb__list {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 12px 16px;
}

.prrb__row {
  height: 20px;
  border-radius: 8px;
  background: #fff7e6;
}

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

@media (max-width: 340px) {
  .prrb__phone {
    width: 176px;
    height: 132px;
  }
  .prrb__zone {
    height: 44px;
  }
  .prrb__ring {
    width: 28px;
    height: 28px;
  }
  .prrb__list {
    padding: 8px 12px;
    gap: 4px;
  }
  .prrb__row {
    height: 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .prrb__knob, .prrb__list {
    transition: none !important;
  }
}

(function () {
  var phone = document.getElementById('prrbPhone');
  var knob = document.getElementById('prrbKnob');
  var list = document.getElementById('prrbList');
  var hint = document.getElementById('prrbHint');
  var root = document.getElementById('prrb');

  // 계산 겹: 당긴 거리(raw)를 기준 거리(REF)로 나눈 비율(ratio)만큼 knob 을 궤도(SWEEP도)로 돌린다.
  // ratio 가 1 이 되면 거리 연동을 놓고 각속도(SPIN_SPEED)로 계속 도는 로딩 상태로 넘어간다.
  var REF = 120, SWEEP = 270, RADIUS = 18, SPIN_SPEED = 0.62; // deg / ms

  function place(angleDeg, pullPx) {
    var rad = (angleDeg - 90) * Math.PI / 180;
    var x = Math.cos(rad) * RADIUS, y = Math.sin(rad) * RADIUS;
    knob.style.transform = 'translate(' + x.toFixed(1) + 'px,' + y.toFixed(1) + 'px)';
    list.style.transform = 'translateY(' + pullPx.toFixed(1) + 'px)';
  }

  var state = 'idle'; // idle -> dragging -> spinning -> idle
  var raw = 0, ratio = 0, spinAngle = 0, spinStart = 0, spinRaf = null;

  function fromRatio() { return ratio * SWEEP; }

  function spinFrame(ts) {
    if (!spinStart) { spinStart = ts; }
    var el = ts - spinStart;
    spinAngle = (el * SPIN_SPEED) % 360;
    place(spinAngle, 24);
    if (el < 900) {
      spinRaf = requestAnimationFrame(spinFrame);
    } else {
      state = 'idle'; ratio = 0; raw = 0; spinStart = 0;
      hint.textContent = 'Pull to refresh';
      place(0, 0);
    }
  }

  function startSpin() {
    state = 'spinning';
    hint.textContent = 'Loading';
    spinStart = 0;
    spinRaf = requestAnimationFrame(spinFrame);
  }

  function apply(r) {
    raw = r;
    ratio = Math.max(0, Math.min(1, raw / REF));
    place(fromRatio(), ratio * 24);
    hint.textContent = ratio > 0.05 ? ('Rotation ' + Math.round(fromRatio()) + 'deg · Ratio ' + Math.round(ratio * 100) + '%') : 'Pull to refresh';
  }

  var dragging = false, startY = 0, startRaw = 0;
  function onDown(y) {
    if (state === 'spinning') { return; }
    dragging = true; state = 'dragging'; startY = y; startRaw = raw;
  }
  function onMove(y) {
    if (!dragging) { return; }
    apply(Math.max(0, Math.min(REF * 1.3, startRaw + (y - startY))));
  }
  function onUp() {
    if (!dragging) { return; }
    dragging = false;
    if (ratio >= 1) { startSpin(); } else { state = 'idle'; apply(0); }
  }

  function wireReal() {
    phone.addEventListener('pointerdown', function (e) { root.classList.remove('is-demo'); stopAutoplay(); onDown(e.clientY); });
    window.addEventListener('pointermove', function (e) { onMove(e.clientY); });
    window.addEventListener('pointerup', onUp);
  }
  phone.style.touchAction = 'none';
  wireReal();
  place(0, 0);

  // 자동 루프: raw 를 단계적으로 REF 까지 올려 같은 apply()·startSpin() 경로를 탄다.
  var autoRaw = 0, autoTimer = null;
  function autoTick() {
    if (state === 'spinning') { return; }
    autoRaw += 30;
    if (autoRaw >= REF) { apply(REF); startSpin(); autoRaw = 0; return; }
    apply(autoRaw);
  }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } if (spinRaf) { cancelAnimationFrame(spinRaf); } }
  if (!reduce) { autoTimer = setInterval(autoTick, 170); }
})();

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

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

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

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

    // 계산 겹: 당긴 거리(raw)를 기준 거리(REF)로 나눈 비율(ratio)만큼 knob 을 궤도(SWEEP도)로 돌린다.
    // ratio 가 1 이 되면 거리 연동을 놓고 각속도(SPIN_SPEED)로 계속 도는 로딩 상태로 넘어간다.
    const REF = 120, SWEEP = 270, RADIUS = 18, SPIN_SPEED = 0.62;

    function place(angleDeg: number, pullPx: number) {
      const rad = (angleDeg - 90) * Math.PI / 180;
      const x = Math.cos(rad) * RADIUS, y = Math.sin(rad) * RADIUS;
      knob!.style.transform = "translate(" + x.toFixed(1) + "px," + y.toFixed(1) + "px)";
      list!.style.transform = "translateY(" + pullPx.toFixed(1) + "px)";
    }

    let state: "idle" | "dragging" | "spinning" = "idle";
    let raw = 0, ratio = 0, spinAngle = 0, spinStart = 0, spinRaf: number | null = null;
    function fromRatio() { return ratio * SWEEP; }

    function spinFrame(ts: number) {
      if (!spinStart) { spinStart = ts; }
      const el = ts - spinStart;
      spinAngle = (el * SPIN_SPEED) % 360;
      place(spinAngle, 24);
      if (el < 900) {
        spinRaf = requestAnimationFrame(spinFrame);
      } else {
        state = "idle"; ratio = 0; raw = 0; spinStart = 0;
        hint!.textContent = "당겨서 새로고침";
        place(0, 0);
      }
    }
    function startSpin() {
      state = "spinning";
      hint!.textContent = "불러오는 중";
      spinStart = 0;
      spinRaf = requestAnimationFrame(spinFrame);
    }

    function apply(r: number) {
      raw = r;
      ratio = Math.max(0, Math.min(1, raw / REF));
      place(fromRatio(), ratio * 24);
      hint!.textContent = ratio > 0.05 ? ("회전 " + Math.round(fromRatio()) + "도 · 비율 " + Math.round(ratio * 100) + "%") : "당겨서 새로고침";
    }

    let dragging = false, startY = 0, startRaw = 0;
    function onDown(y: number) {
      if (state === "spinning") return;
      dragging = true; state = "dragging"; startY = y; startRaw = raw;
    }
    function onMove(y: number) {
      if (!dragging) return;
      apply(Math.max(0, Math.min(REF * 1.3, startRaw + (y - startY))));
    }
    function onUp() {
      if (!dragging) return;
      dragging = false;
      if (ratio >= 1) { startSpin(); } else { state = "idle"; apply(0); }
    }

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

    let autoRaw = 0, autoTimer: number | null = null;
    function autoTick() {
      if (state === "spinning") return;
      autoRaw += 30;
      if (autoRaw >= REF) { apply(REF); startSpin(); autoRaw = 0; return; }
      apply(autoRaw);
    }
    function stopAutoplay() {
      if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; }
      if (spinRaf !== null) { cancelAnimationFrame(spinRaf); }
    }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { autoTimer = window.setInterval(autoTick, 170); }

    return () => {
      stopAutoplay();
      phone.removeEventListener("pointerdown", onPointerDown);
      window.removeEventListener("pointermove", onPointerMove);
      window.removeEventListener("pointerup", onUp);
    };
  }, []);

  return (
    <div ref={rootRef} className={styles.stage}>
      <div className={styles.prrb}>
        <div className={styles.phone}>
          <div className={styles.zone}>
            <span className={styles.ring} />
            <span className={styles.knob} style={{ background: color }} />
          </div>
          <div className={styles.list}>
            <div className={styles.row} />
            <div className={styles.row} />
            <div className={styles.row} />
          </div>
        </div>
        <span className={styles.hint}>당겨서 새로고침</span>
      </div>
    </div>
  );
}