04Submenu cascade open — a submenu opens once the hovered duration value passes a set amount

<main class="stage">
<div class="cm is-demo" id="cm">
  <div class="cm__field" id="cmField">
    <span class="cm__hint">Right-click → hover on Sort</span>
  </div>
  <div class="cm__menu" id="cmMenu" role="menu">
    <button class="cm__item" type="button" role="menuitem">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M216 40v128h-48V88H88V40Z" opacity=".2"/><path d="M216 32H88a8 8 0 0 0-8 8v40H40a8 8 0 0 0-8 8v128a8 8 0 0 0 8 8h128a8 8 0 0 0 8-8v-40h40a8 8 0 0 0 8-8V40a8 8 0 0 0-8-8m-56 176H48V96h112Zm48-48h-32V88a8 8 0 0 0-8-8H96V48h112Z"/></g></svg></span>
      <span>Copy</span>
    </button>
    <button class="cm__item" type="button" role="menuitem">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 48v168a8 8 0 0 1-8 8H56a8 8 0 0 1-8-8V48a8 8 0 0 1 8-8h40a39.83 39.83 0 0 0-8 24v8h80v-8a39.83 39.83 0 0 0-8-24h40a8 8 0 0 1 8 8" opacity=".2"/><path d="M200 32h-36.26a47.92 47.92 0 0 0-71.48 0H56a16 16 0 0 0-16 16v168a16 16 0 0 0 16 16h144a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m-72 0a32 32 0 0 1 32 32H96a32 32 0 0 1 32-32m72 184H56V48h26.75A47.9 47.9 0 0 0 80 64v8a8 8 0 0 0 8 8h80a8 8 0 0 0 8-8v-8a47.9 47.9 0 0 0-2.75-16H200Z"/></g></svg></span>
      <span>Paste</span>
    </button>
    <button class="cm__item cm__item--active" type="button" role="menuitem" id="cmSortTrigger">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M184 88v104a8 8 0 0 1-13.66 5.66l-32-32a8 8 0 0 1 0-11.32L170.34 122A8 8 0 0 1 184 88M72 88v104a8 8 0 0 0 13.66 5.66l32-32a8 8 0 0 0 0-11.32L85.66 122A8 8 0 0 0 72 88" opacity=".2"/><path d="M226.83 82.34a8 8 0 0 0-8.72 1.73l-32 32a8 8 0 0 0 0 11.32l32 32A8 8 0 0 0 232 154V90a8 8 0 0 0-5.17-7.66M216 134.69L197.31 116L216 97.31ZM37.86 116l32-32a8 8 0 0 1 13.66 5.66v64A8 8 0 0 1 69.86 159l-32-32a8 8 0 0 1 0-11m14.28 5.66L59.86 130V102Z"/></g></svg></span>
      <span>Sort</span>
      <span class="cm__caret"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><path fill="currentColor" d="M181.66 133.66l-80 80a8 8 0 0 1-11.32-11.32L164.69 128L90.34 53.66a8 8 0 0 1 11.32-11.32l80 80a8 8 0 0 1 0 11.32"/></svg></span>
    </button>
    <button class="cm__item cm__item--danger" type="button" role="menuitem">
      <span class="cm__ic"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M200 56v152a8 8 0 0 1-8 8H64a8 8 0 0 1-8-8V56Z" opacity=".2"/><path d="M216 48h-40v-8a24 24 0 0 0-24-24h-48a24 24 0 0 0-24 24v8H40a8 8 0 0 0 0 16h8v144a16 16 0 0 0 16 16h128a16 16 0 0 0 16-16V64h8a8 8 0 0 0 0-16M96 40a8 8 0 0 1 8-8h48a8 8 0 0 1 8 8v8H96Zm96 168H64V64h128Zm-80-104v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0m48 0v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0"/></g></svg></span>
      <span>Delete</span>
    </button>
  </div>
  <div class="cm__sub" id="cmSub" role="menu">
    <button class="cm__item" type="button" role="menuitem"><span>By name</span></button>
    <button class="cm__item" type="button" role="menuitem"><span>By date</span></button>
    <button class="cm__item" type="button" role="menuitem"><span>By size</span></button>
  </div>
</div>
</main>

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

// 계산 겹: 부모 항목 위에 머무른 시간이 CASCADE_MS 를 넘는지 타이머로 재고, 넘으면 그 항목의
// 오른쪽 경계 좌표 값을 하위 목록의 왼쪽 좌표 값으로 그대로 물려 옆에 이어 붙인다 (openSub()).
@include stage($stage-paper);

.cm {
  position: relative;
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
}

.cm__field {
  width: clamp(190px, 60vw, 260px);
  height: 130px;
  border-radius: $r-card;
  background: $subject-blue-deep;
  color: $subject-cream;
  display: grid;
  place-items: center;
  padding: $sp-3;
  box-sizing: border-box;
  font: 600 14px/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  text-align: center;
  user-select: none;
}

.cm__hint { opacity: .85; font-weight: 500; font-size: 12px; }

.cm__menu {
  position: fixed;
  top: 0;
  left: 0;
  min-width: 156px;
  background: $stage-paper;
  border-radius: $r-sm;
  box-shadow: $shadow-raised;
  padding: $sp-1;
  display: grid;
  gap: $sp-1;
  opacity: 0;
  transform: scale(.94);
  transform-origin: top left;
  pointer-events: none;
  transition: opacity $dur-quick $ease-out, transform $dur-quick $ease-out;
  z-index: 5;

  &.is-open { opacity: 1; transform: scale(1); pointer-events: auto; }
}

.cm__sub {
  position: fixed;
  top: 0;
  left: 0;
  min-width: 132px;
  background: $stage-paper;
  border-radius: $r-sm;
  box-shadow: $shadow-raised;
  padding: $sp-1;
  display: grid;
  gap: $sp-1;
  opacity: 0;
  transform: scale(.9);
  transform-origin: top left;
  pointer-events: none;
  transition: opacity $dur-quick $ease-pop, transform $dur-quick $ease-pop;
  z-index: 6;

  &.is-open { opacity: 1; transform: scale(1); pointer-events: auto; }
}

.cm__item {
  position: relative;
  display: flex;
  align-items: center;
  gap: $sp-2;
  padding: $sp-2 $sp-3;
  border: 0;
  background: none;
  border-radius: $r-xs;
  font: 500 13px/1.2 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: $subject-ink;
  cursor: pointer;
  text-align: left;

  &:hover, &:focus-visible, &--active { background: rgba($subject-ink, .08); }
  &--danger { color: $error; }
}

.cm__caret { margin-left: auto; width: 12px; height: 12px; color: rgba($subject-ink, .55); }
.cm__caret svg { display: block; width: 100%; height: 100%; }

.cm__ic {
  width: 16px;
  height: 16px;
  flex: none;
  color: $subject-blue;

  svg { display: block; width: 100%; height: 100%; }
}
.cm__item--danger .cm__ic { color: $error; }

@media (max-width: 340px) {
  .cm__field { width: 176px; height: 108px; font-size: 12px; padding: $sp-2; }
  .cm__menu { min-width: 132px; }
  .cm__sub { min-width: 112px; }
  .cm__item { padding: $sp-1 $sp-2; font-size: 12px; }
}

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

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

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

.cm {
  position: relative;
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
}

.cm__field {
  width: clamp(190px, 60vw, 260px);
  height: 130px;
  border-radius: 16px;
  background: #0a4fe8;
  color: #fff7e6;
  display: grid;
  place-items: center;
  padding: 12px;
  box-sizing: border-box;
  font: 600 14px/1.3 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  text-align: center;
  user-select: none;
}

.cm__hint {
  opacity: 0.85;
  font-weight: 500;
  font-size: 12px;
}

.cm__menu {
  position: fixed;
  top: 0;
  left: 0;
  min-width: 156px;
  background: #ffffff;
  border-radius: 8px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  padding: 4px;
  display: grid;
  gap: 4px;
  opacity: 0;
  transform: scale(0.94);
  transform-origin: top left;
  pointer-events: none;
  transition: opacity 220ms ease-out, transform 220ms ease-out;
  z-index: 5;
}
.cm__menu.is-open {
  opacity: 1;
  transform: scale(1);
  pointer-events: auto;
}

.cm__sub {
  position: fixed;
  top: 0;
  left: 0;
  min-width: 132px;
  background: #ffffff;
  border-radius: 8px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  padding: 4px;
  display: grid;
  gap: 4px;
  opacity: 0;
  transform: scale(0.9);
  transform-origin: top left;
  pointer-events: none;
  transition: opacity 220ms cubic-bezier(0.2, 1.4, 0.4, 1), transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
  z-index: 6;
}
.cm__sub.is-open {
  opacity: 1;
  transform: scale(1);
  pointer-events: auto;
}

.cm__item {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border: 0;
  background: none;
  border-radius: 4px;
  font: 500 13px/1.2 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: #17141a;
  cursor: pointer;
  text-align: left;
}
.cm__item:hover, .cm__item:focus-visible, .cm__item--active {
  background: rgba(23, 20, 26, 0.08);
}
.cm__item--danger {
  color: #c2361a;
}

.cm__caret {
  margin-left: auto;
  width: 12px;
  height: 12px;
  color: rgba(23, 20, 26, 0.55);
}

.cm__caret svg {
  display: block;
  width: 100%;
  height: 100%;
}

.cm__ic {
  width: 16px;
  height: 16px;
  flex: none;
  color: #2f6df6;
}
.cm__ic svg {
  display: block;
  width: 100%;
  height: 100%;
}

.cm__item--danger .cm__ic {
  color: #c2361a;
}

@media (max-width: 340px) {
  .cm__field {
    width: 176px;
    height: 108px;
    font-size: 12px;
    padding: 8px;
  }
  .cm__menu {
    min-width: 132px;
  }
  .cm__sub {
    min-width: 112px;
  }
  .cm__item {
    padding: 4px 8px;
    font-size: 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cm__menu, .cm__sub {
    transition: none;
  }
}

(function () {
  var field = document.getElementById('cmField');
  var menu = document.getElementById('cmMenu');
  var sub = document.getElementById('cmSub');
  var trigger = document.getElementById('cmSortTrigger');
  var root = document.getElementById('cm');
  var GAP = 6;
  var CASCADE_MS = 260;

  function place(el, x, y) {
    var w = el.offsetWidth, h = el.offsetHeight;
    var vw = document.documentElement.clientWidth, vh = document.documentElement.clientHeight;
    var px = Math.max(GAP, Math.min(x, vw - w - GAP));
    var py = Math.max(GAP, Math.min(y, vh - h - GAP));
    el.style.left = px.toFixed(0) + 'px';
    el.style.top = py.toFixed(0) + 'px';
    return { left: px, top: py, right: px + w, width: w };
  }

  var hoverTimer = null;
  function openMenu(x, y) {
    menu.style.left = '0px'; menu.style.top = '0px';
    var box = place(menu, x, y);
    menu.classList.add('is-open');
  }
  function closeAll() {
    menu.classList.remove('is-open');
    sub.classList.remove('is-open');
    clearHover();
  }
  function clearHover() { if (hoverTimer) { clearTimeout(hoverTimer); hoverTimer = null; } }

  function scheduleSub() {
    clearHover();
    // 계산 겹: Sort 항목 위에 머무른 시간을 CASCADE_MS 로 재고, 그 시간을 넘겨야만 서브메뉴를 연다
    // (즉시 열지 않음 — 지나가는 커서에 반응하지 않게).
    hoverTimer = setTimeout(function () {
      var mr = menu.getBoundingClientRect();
      var tr = trigger.getBoundingClientRect();
      place(sub, mr.right - 2, tr.top - 4);
      sub.classList.add('is-open');
    }, CASCADE_MS);
  }

  trigger.addEventListener('pointerenter', scheduleSub);
  trigger.addEventListener('pointerleave', function () { clearHover(); });

  field.addEventListener('contextmenu', function (e) {
    e.preventDefault();
    root.classList.remove('is-demo'); stopAutoplay();
    closeAll();
    openMenu(e.clientX, e.clientY);
  });
  document.addEventListener('pointerdown', function (e) {
    if (menu.classList.contains('is-open') && !menu.contains(e.target) && !sub.contains(e.target) && e.target !== field) {
      closeAll();
    }
  });

  // 자동 루프: 메뉴를 연 뒤 Sort 항목 위에 CASCADE_MS 이상 머물러 서브메뉴가 계단식으로 이어 붙는
  // 것을 보여주고, 잠시 뒤 닫는다.
  var step = 0, autoTimer = null;
  function autoTick() {
    var phase = step % 4;
    if (phase === 0) {
      var r = field.getBoundingClientRect();
      openMenu(r.left + r.width * 0.5, r.top + r.height * 0.6);
    } else if (phase === 1) {
      scheduleSub();
    } else if (phase === 3) {
      closeAll();
    }
    step++;
  }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } clearHover(); }
  if (!reduce) { autoTimer = setInterval(autoTick, CASCADE_MS + 140); autoTick(); }
})();

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

const ICON_COPY = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M216 40v128h-48V88H88V40Z" opacity=".2"/><path d="M216 32H88a8 8 0 0 0-8 8v40H40a8 8 0 0 0-8 8v128a8 8 0 0 0 8 8h128a8 8 0 0 0 8-8v-40h40a8 8 0 0 0 8-8V40a8 8 0 0 0-8-8m-56 176H48V96h112Zm48-48h-32V88a8 8 0 0 0-8-8H96V48h112Z"/></g></svg>';
const ICON_PASTE = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 48v168a8 8 0 0 1-8 8H56a8 8 0 0 1-8-8V48a8 8 0 0 1 8-8h40a39.83 39.83 0 0 0-8 24v8h80v-8a39.83 39.83 0 0 0-8-24h40a8 8 0 0 1 8 8" opacity=".2"/><path d="M200 32h-36.26a47.92 47.92 0 0 0-71.48 0H56a16 16 0 0 0-16 16v168a16 16 0 0 0 16 16h144a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m-72 0a32 32 0 0 1 32 32H96a32 32 0 0 1 32-32m72 184H56V48h26.75A47.9 47.9 0 0 0 80 64v8a8 8 0 0 0 8 8h80a8 8 0 0 0 8-8v-8a47.9 47.9 0 0 0-2.75-16H200Z"/></g></svg>';
const ICON_SORT = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M184 88v104a8 8 0 0 1-13.66 5.66l-32-32a8 8 0 0 1 0-11.32L170.34 122A8 8 0 0 1 184 88M72 88v104a8 8 0 0 0 13.66 5.66l32-32a8 8 0 0 0 0-11.32L85.66 122A8 8 0 0 0 72 88" opacity=".2"/><path d="M226.83 82.34a8 8 0 0 0-8.72 1.73l-32 32a8 8 0 0 0 0 11.32l32 32A8 8 0 0 0 232 154V90a8 8 0 0 0-5.17-7.66M216 134.69L197.31 116L216 97.31ZM37.86 116l32-32a8 8 0 0 1 13.66 5.66v64A8 8 0 0 1 69.86 159l-32-32a8 8 0 0 1 0-11m14.28 5.66L59.86 130V102Z"/></g></svg>';
const ICON_CARET = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><path fill="currentColor" d="M181.66 133.66l-80 80a8 8 0 0 1-11.32-11.32L164.69 128L90.34 53.66a8 8 0 0 1 11.32-11.32l80 80a8 8 0 0 1 0 11.32"/></svg>';
const ICON_TRASH = '<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256"><g fill="currentColor"><path d="M200 56v152a8 8 0 0 1-8 8H64a8 8 0 0 1-8-8V56Z" opacity=".2"/><path d="M216 48h-40v-8a24 24 0 0 0-24-24h-48a24 24 0 0 0-24 24v8H40a8 8 0 0 0 0 16h8v144a16 16 0 0 0 16 16h128a16 16 0 0 0 16-16V64h8a8 8 0 0 0 0-16M96 40a8 8 0 0 1 8-8h48a8 8 0 0 1 8 8v8H96Zm96 168H64V64h128Zm-80-104v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0m48 0v64a8 8 0 0 1-16 0v-64a8 8 0 0 1 16 0"/></g></svg>';

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

export default function SubmenuCascadeOpen({
  color = "#2f6df6",
}: SubmenuCascadeOpenProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const field = root.querySelector<HTMLDivElement>(`.${styles.field}`);
    const menu = root.querySelector<HTMLDivElement>(`.${styles.menu}`);
    const sub = root.querySelector<HTMLDivElement>(`.${styles.sub}`);
    const trigger = root.querySelector<HTMLButtonElement>(`.${styles.trigger}`);
    if (!field || !menu || !sub || !trigger) return;
    const GAP = 6;
    const CASCADE_MS = 260;

    function place(el: HTMLElement, x: number, y: number) {
      const w = el.offsetWidth, h = el.offsetHeight;
      const vw = document.documentElement.clientWidth, vh = document.documentElement.clientHeight;
      const px = Math.max(GAP, Math.min(x, vw - w - GAP));
      const py = Math.max(GAP, Math.min(y, vh - h - GAP));
      el.style.left = px.toFixed(0) + "px";
      el.style.top = py.toFixed(0) + "px";
    }

    let hoverTimer: number | null = null;
    function openMenu(x: number, y: number) {
      menu!.style.left = "0px"; menu!.style.top = "0px";
      place(menu!, x, y);
      menu!.classList.add(styles.open);
    }
    function clearHover() { if (hoverTimer !== null) { window.clearTimeout(hoverTimer); hoverTimer = null; } }
    function closeAll() { menu!.classList.remove(styles.open); sub!.classList.remove(styles.subOpen); clearHover(); }

    // 계산 겹: 정렬 항목 위에 머무른 시간을 CASCADE_MS 로 재고, 그 시간을 넘겨야만 서브메뉴를
    // 연다(즉시 열지 않음 — 지나가는 커서에 반응하지 않게).
    function scheduleSub() {
      clearHover();
      hoverTimer = window.setTimeout(() => {
        const mr = menu!.getBoundingClientRect();
        const tr = trigger!.getBoundingClientRect();
        place(sub!, mr.right - 2, tr.top - 4);
        sub!.classList.add(styles.subOpen);
      }, CASCADE_MS);
    }

    trigger.addEventListener("pointerenter", scheduleSub);
    const onLeave = () => clearHover();
    trigger.addEventListener("pointerleave", onLeave);

    function onContextMenu(e: MouseEvent) { e.preventDefault(); stopAutoplay(); closeAll(); openMenu(e.clientX, e.clientY); }
    function onDocDown(e: PointerEvent) {
      if (menu!.classList.contains(styles.open) && !menu!.contains(e.target as Node) && !sub!.contains(e.target as Node) && e.target !== field) closeAll();
    }
    field.addEventListener("contextmenu", onContextMenu);
    document.addEventListener("pointerdown", onDocDown);

    let step = 0;
    let autoTimer: number | null = null;
    function autoTick() {
      const phase = step % 4;
      if (phase === 0) {
        const r = field!.getBoundingClientRect();
        openMenu(r.left + r.width * 0.5, r.top + r.height * 0.6);
      } else if (phase === 1) {
        scheduleSub();
      } else if (phase === 3) {
        closeAll();
      }
      step++;
    }
    function stopAutoplay() { if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; } clearHover(); }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { autoTimer = window.setInterval(autoTick, CASCADE_MS + 140); autoTick(); }

    return () => {
      stopAutoplay();
      field.removeEventListener("contextmenu", onContextMenu);
      document.removeEventListener("pointerdown", onDocDown);
      trigger.removeEventListener("pointerenter", scheduleSub);
      trigger.removeEventListener("pointerleave", onLeave);
    };
  }, []);

  return (
    <div ref={rootRef} className={styles.stage}>
      <div className={styles.cm}>
        <div className={styles.field}>
          <span className={styles.hint}>우클릭 → 정렬에 머무르기</span>
        </div>
        <div className={styles.menu} role="menu">
          <button type="button" className={styles.item} role="menuitem">
            <span className={styles.ic} style={{ color }} dangerouslySetInnerHTML={{ __html: ICON_COPY }} />
            <span>복사</span>
          </button>
          <button type="button" className={styles.item} role="menuitem">
            <span className={styles.ic} style={{ color }} dangerouslySetInnerHTML={{ __html: ICON_PASTE }} />
            <span>붙여넣기</span>
          </button>
          <button type="button" className={`${styles.item} ${styles.active} ${styles.trigger}`} role="menuitem">
            <span className={styles.ic} style={{ color }} dangerouslySetInnerHTML={{ __html: ICON_SORT }} />
            <span>정렬</span>
            <span className={styles.caret} dangerouslySetInnerHTML={{ __html: ICON_CARET }} />
          </button>
          <button type="button" className={`${styles.item} ${styles.danger}`} role="menuitem">
            <span className={styles.ic} dangerouslySetInnerHTML={{ __html: ICON_TRASH }} />
            <span>삭제</span>
          </button>
        </div>
        <div className={styles.sub} role="menu">
          <button type="button" className={styles.item} role="menuitem"><span>이름순</span></button>
          <button type="button" className={styles.item} role="menuitem"><span>날짜순</span></button>
          <button type="button" className={styles.item} role="menuitem"><span>크기순</span></button>
        </div>
      </div>
    </div>
  );
}