06Pick-up and drop event card

<main class="stage">
  <div class="dd is-demo">
    <div class="dd__head">
      <span class="dd__ico" aria-hidden="true"><svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 108v44a80 80 0 0 1-160 0v-12a20 20 0 0 1 20-20h20V92a20 20 0 0 1 40 0a20 20 0 0 1 40 0v16a20 20 0 0 1 40 0" opacity=".2"/><path d="M188 80a27.8 27.8 0 0 0-13.36 3.4a28 28 0 0 0-46.64-11A28 28 0 0 0 80 92v20H68a28 28 0 0 0-28 28v12a88 88 0 0 0 176 0v-44a28 28 0 0 0-28-28m12 72a72 72 0 0 1-144 0v-12a12 12 0 0 1 12-12h12v24a8 8 0 0 0 16 0V92a12 12 0 0 1 24 0v28a8 8 0 0 0 16 0V92a12 12 0 0 1 24 0v28a8 8 0 0 0 16 0v-12a12 12 0 0 1 24 0Z"/></g></svg></span>
      <span class="dd__title">2026. 9</span>
      <span class="dd__live" id="dd-live" role="status" aria-live="polite"></span>
    </div>
    <div class="dd__dow" aria-hidden="true"><span>M</span><span>T</span><span>W</span><span>T</span><span>F</span></div>
    <div class="dd__grid" id="dd-grid" role="grid" aria-label="Move-event calendar">
      <div class="dd__r" role="row">
        <div class="dd__c" role="gridcell" data-d="7"><span class="dd__n">7</span></div>
        <div class="dd__c dd__c--from" role="gridcell" data-d="8"><span class="dd__n">8</span><button class="dd__chip dd__chip--fly" type="button" aria-grabbed="false"><span class="dd__grip" aria-hidden="true"><svg xmlns="http://www.w3.org/2000/svg" width="9" height="9" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 32v192a16 16 0 0 1-16 16H64a16 16 0 0 1-16-16V32a16 16 0 0 1 16-16h128a16 16 0 0 1 16 16" opacity=".2"/><path d="M104 60a12 12 0 1 1-12-12a12 12 0 0 1 12 12m60 12a12 12 0 1 0-12-12a12 12 0 0 0 12 12m-72 44a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12m-72 68a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12"/></g></svg></span><span class="dd__t">Review</span></button></div>
        <div class="dd__c dd__c--to" role="gridcell" data-d="9"><span class="dd__n">9</span></div>
        <div class="dd__c" role="gridcell" data-d="10"><span class="dd__n">10</span></div>
        <div class="dd__c" role="gridcell" data-d="11"><span class="dd__n">11</span></div>
      </div>
      <div class="dd__r" role="row">
        <div class="dd__c" role="gridcell" data-d="14"><span class="dd__n">14</span></div>
        <div class="dd__c" role="gridcell" data-d="15" aria-current="date"><span class="dd__n is-today">15</span></div>
        <div class="dd__c" role="gridcell" data-d="16"><span class="dd__n">16</span><button class="dd__chip" type="button" aria-grabbed="false"><span class="dd__grip" aria-hidden="true"><svg xmlns="http://www.w3.org/2000/svg" width="9" height="9" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 32v192a16 16 0 0 1-16 16H64a16 16 0 0 1-16-16V32a16 16 0 0 1 16-16h128a16 16 0 0 1 16 16" opacity=".2"/><path d="M104 60a12 12 0 1 1-12-12a12 12 0 0 1 12 12m60 12a12 12 0 1 0-12-12a12 12 0 0 0 12 12m-72 44a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12m-72 68a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12"/></g></svg></span><span class="dd__t">Deploy</span></button></div>
        <div class="dd__c" role="gridcell" data-d="17"><span class="dd__n">17</span></div>
        <div class="dd__c" role="gridcell" data-d="18"><span class="dd__n">18</span></div>
      </div>
      <div class="dd__r" role="row">
        <div class="dd__c" role="gridcell" data-d="21"><span class="dd__n">21</span></div>
        <div class="dd__c" role="gridcell" data-d="22"><span class="dd__n">22</span></div>
        <div class="dd__c" role="gridcell" data-d="23"><span class="dd__n">23</span></div>
        <div class="dd__c" role="gridcell" data-d="24"><span class="dd__n">24</span><button class="dd__chip" type="button" aria-grabbed="false"><span class="dd__grip" aria-hidden="true"><svg xmlns="http://www.w3.org/2000/svg" width="9" height="9" viewBox="0 0 256 256"><g fill="currentColor"><path d="M208 32v192a16 16 0 0 1-16 16H64a16 16 0 0 1-16-16V32a16 16 0 0 1 16-16h128a16 16 0 0 1 16 16" opacity=".2"/><path d="M104 60a12 12 0 1 1-12-12a12 12 0 0 1 12 12m60 12a12 12 0 1 0-12-12a12 12 0 0 0 12 12m-72 44a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12m-72 68a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12"/></g></svg></span><span class="dd__t">Retro</span></button></div>
        <div class="dd__c" role="gridcell" data-d="25"><span class="dd__n">25</span></div>
      </div>
    </div>
  </div>
</main>

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

$duration: $dur-quick;
$easing:   $ease-spring;
$color:    $subject-blue;

@include stage($stage-paper);

.dd {
  // 한 칸 옆으로 옮기는 거리 = 칸 폭 + gap. 격자 폭이 min(320px, 90vw) 이므로 계산으로 얻는다
  --step: calc((min(320px, 90vw) + #{$sp-1}) / 5);
  box-sizing: border-box;
  width: min(320px, 90vw);
  color: $subject-ink;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

.dd__head { display: flex; align-items: center; gap: $sp-2; margin: 0 0 $sp-2; }
.dd__ico { display: inline-flex; color: $color; }
.dd__title { font-size: clamp(11px, 3.4vw, 14px); font-weight: 700; }
.dd__live {
  margin-left: auto;
  font-size: clamp(8px, 2.4vw, 10px);
  font-weight: 700;
  color: $subject-blue-deep;   // 밝은 면 위 파란 글자 — 5.74:1
  white-space: nowrap;
}

.dd__dow {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: $sp-1;
  margin: 0 0 $sp-1;
  font-size: clamp(8px, 2.4vw, 10px);
  font-weight: 700;
  text-align: center;
  color: rgba(23, 20, 26, .72);   // AA 4.5 (.45 는 2.97:1 이었다)
}

.dd__grid { display: flex; flex-direction: column; gap: $sp-1; }
.dd__r { display: grid; grid-template-columns: repeat(5, 1fr); gap: $sp-1; }

.dd__c {
  position: relative;
  box-sizing: border-box;
  height: clamp(34px, 10.5vw, 42px);
  border-radius: $r-sm;
  background: rgba(23, 20, 26, .05);
}
// 받을 준비 — 점선 테두리
.dd__c::after {
  content: "";
  position: absolute;
  inset: 0;
  border: 2px dashed $color;
  border-radius: $r-sm;
  opacity: 0;
  pointer-events: none;
  transition: opacity $duration $easing;
}
.dd__c.is-over::after { opacity: 1; }

.dd__n {
  position: absolute;
  top: $sp-1; left: $sp-1;
  font-size: clamp(8px, 2.4vw, 10px);
  font-weight: 700;
  color: rgba(23, 20, 26, .72);   // AA 4.5 (.5 는 3.37:1 이었다)
}
.dd__n.is-today {
  color: $subject-blue-deep;   // 밝은 면 위 파란 글자 — 5.74:1
  text-decoration: underline;
  text-underline-offset: 2px;
}

.dd__chip {
  position: absolute;
  left: $sp-1; right: $sp-1; bottom: $sp-1;
  box-sizing: border-box;
  height: clamp(14px, 4.4vw, 18px);
  display: flex;
  align-items: center;
  gap: $sp-1;
  padding: 0 $sp-1;
  border: 0;
  border-radius: $r-xs;
  background: $subject-blue-deep;
  color: $subject-cream;
  font-family: inherit;
  font-size: clamp(8px, 2.3vw, 9px);
  font-weight: 700;
  line-height: 1;
  cursor: grab;
  touch-action: none;
  overflow: hidden;
  white-space: nowrap;
  transition: box-shadow $duration $easing, transform $duration $easing;
}
.dd__grip { display: inline-flex; flex: 0 0 auto; opacity: .75; }
.dd__t { overflow: hidden; text-overflow: ellipsis; }
.dd__chip:focus-visible { outline: 2px solid $subject-ink; outline-offset: 2px; }
// 집힌 상태 — 떠서 기울고 그림자가 깊어진다. pointer-events 를 끊어야 밑의 칸을 집어낼 수 있다
.dd__chip.is-grab {
  z-index: 5;
  transform: translateY(-6px) scale(1.06) rotate(-4deg);
  box-shadow: $shadow-raised;
  cursor: grabbing;
  pointer-events: none;
}

// ── 자동 루프: 칩 하나가 옆 칸으로 떠서 옮겨갔다 돌아온다 (2s) ──
.dd.is-demo .dd__chip--fly {
  z-index: 5;
  animation-name: dd-fly;
  animation-duration: $dur-loop;
  animation-timing-function: $easing;
  animation-iteration-count: infinite;
}
.dd.is-demo .dd__c--to::after {
  animation-name: dd-ring;
  animation-duration: $dur-loop;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}
.dd.is-demo .dd__c--from::after {
  animation-name: dd-ring-back;
  animation-duration: $dur-loop;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}

@keyframes dd-fly {
  0%, 6%   { transform: translate(0, 0) scale(1) rotate(0deg); box-shadow: 0 0 0 rgba(23, 20, 26, 0); }
  20%      { transform: translate(0, -6px) scale(1.06) rotate(-4deg); box-shadow: $shadow-raised; }
  40%      { transform: translate(var(--step), -6px) scale(1.06) rotate(-4deg); box-shadow: $shadow-raised; }
  50%, 58% { transform: translate(var(--step), 0) scale(1) rotate(0deg); box-shadow: 0 0 0 rgba(23, 20, 26, 0); }
  70%      { transform: translate(var(--step), -6px) scale(1.06) rotate(4deg); box-shadow: $shadow-raised; }
  88%      { transform: translate(0, -6px) scale(1.06) rotate(4deg); box-shadow: $shadow-raised; }
  100%     { transform: translate(0, 0) scale(1) rotate(0deg); box-shadow: 0 0 0 rgba(23, 20, 26, 0); }
}
@keyframes dd-ring {
  0%, 13%   { opacity: 0; }
  14%, 49%  { opacity: 1; }
  50%, 100% { opacity: 0; }
}
@keyframes dd-ring-back {
  0%, 61%   { opacity: 0; }
  62%, 93%  { opacity: 1; }
  94%, 100% { opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .dd.is-demo .dd__chip--fly,
  .dd.is-demo .dd__c--to::after,
  .dd.is-demo .dd__c--from::after { animation: none !important; }
  .dd__chip, .dd__c::after { 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);
}

.dd {
  --step: calc((min(320px, 90vw) + 4px) / 5);
  box-sizing: border-box;
  width: min(320px, 90vw);
  color: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

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

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

.dd__title {
  font-size: clamp(11px, 3.4vw, 14px);
  font-weight: 700;
}

.dd__live {
  margin-left: auto;
  font-size: clamp(8px, 2.4vw, 10px);
  font-weight: 700;
  color: #0a4fe8;
  white-space: nowrap;
}

.dd__dow {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 4px;
  margin: 0 0 4px;
  font-size: clamp(8px, 2.4vw, 10px);
  font-weight: 700;
  text-align: center;
  color: rgba(23, 20, 26, 0.72);
}

.dd__grid {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.dd__r {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 4px;
}

.dd__c {
  position: relative;
  box-sizing: border-box;
  height: clamp(34px, 10.5vw, 42px);
  border-radius: 8px;
  background: rgba(23, 20, 26, 0.05);
}

.dd__c::after {
  content: "";
  position: absolute;
  inset: 0;
  border: 2px dashed #2f6df6;
  border-radius: 8px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 220ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.dd__c.is-over::after {
  opacity: 1;
}

.dd__n {
  position: absolute;
  top: 4px;
  left: 4px;
  font-size: clamp(8px, 2.4vw, 10px);
  font-weight: 700;
  color: rgba(23, 20, 26, 0.72);
}

.dd__n.is-today {
  color: #0a4fe8;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.dd__chip {
  position: absolute;
  left: 4px;
  right: 4px;
  bottom: 4px;
  box-sizing: border-box;
  height: clamp(14px, 4.4vw, 18px);
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 0 4px;
  border: 0;
  border-radius: 4px;
  background: #0a4fe8;
  color: #fff7e6;
  font-family: inherit;
  font-size: clamp(8px, 2.3vw, 9px);
  font-weight: 700;
  line-height: 1;
  cursor: grab;
  touch-action: none;
  overflow: hidden;
  white-space: nowrap;
  transition: box-shadow 220ms cubic-bezier(0.2, 0.8, 0.2, 1), transform 220ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.dd__grip {
  display: inline-flex;
  flex: 0 0 auto;
  opacity: 0.75;
}

.dd__t {
  overflow: hidden;
  text-overflow: ellipsis;
}

.dd__chip:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 2px;
}

.dd__chip.is-grab {
  z-index: 5;
  transform: translateY(-6px) scale(1.06) rotate(-4deg);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  cursor: grabbing;
  pointer-events: none;
}

.dd.is-demo .dd__chip--fly {
  z-index: 5;
  animation-name: dd-fly;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: infinite;
}

.dd.is-demo .dd__c--to::after {
  animation-name: dd-ring;
  animation-duration: 2s;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}

.dd.is-demo .dd__c--from::after {
  animation-name: dd-ring-back;
  animation-duration: 2s;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}

@keyframes dd-fly {
  0%, 6% {
    transform: translate(0, 0) scale(1) rotate(0deg);
    box-shadow: 0 0 0 rgba(23, 20, 26, 0);
  }
  20% {
    transform: translate(0, -6px) scale(1.06) rotate(-4deg);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  40% {
    transform: translate(var(--step), -6px) scale(1.06) rotate(-4deg);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  50%, 58% {
    transform: translate(var(--step), 0) scale(1) rotate(0deg);
    box-shadow: 0 0 0 rgba(23, 20, 26, 0);
  }
  70% {
    transform: translate(var(--step), -6px) scale(1.06) rotate(4deg);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  88% {
    transform: translate(0, -6px) scale(1.06) rotate(4deg);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  100% {
    transform: translate(0, 0) scale(1) rotate(0deg);
    box-shadow: 0 0 0 rgba(23, 20, 26, 0);
  }
}
@keyframes dd-ring {
  0%, 13% {
    opacity: 0;
  }
  14%, 49% {
    opacity: 1;
  }
  50%, 100% {
    opacity: 0;
  }
}
@keyframes dd-ring-back {
  0%, 61% {
    opacity: 0;
  }
  62%, 93% {
    opacity: 1;
  }
  94%, 100% {
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .dd.is-demo .dd__chip--fly,
  .dd.is-demo .dd__c--to::after,
  .dd.is-demo .dd__c--from::after {
    animation: none !important;
  }
  .dd__chip, .dd__c::after {
    transition: none;
  }
}

// 포인터: pointerdown 으로 집고 pointermove 로 끌고 pointerup 에서 그 칸에 appendChild 한다.
// 키보드: 칩에 포커스 → Space 로 집기 → 화살표로 칸 이동 → Space 로 놓기 (Escape 취소).
var root = document.querySelector('.dd');
var grid = document.getElementById('dd-grid');
var live = document.getElementById('dd-live');
var cells = [].slice.call(grid.querySelectorAll('.dd__c'));
var COLS = 5;
var MSG_GRAB = 'Picked up';
var MSG_DROP = 'Dropped';
var drag = null, held = null, cur = 0;

function armCells(on) {
  for (var i = 0; i < cells.length; i++) {
    if (on) cells[i].setAttribute('aria-dropeffect', 'move');
    else { cells[i].removeAttribute('aria-dropeffect'); cells[i].classList.remove('is-over'); }
  }
}
function drop(chip, cell) {
  if (cell && cell !== chip.parentNode) { cell.appendChild(chip); live.textContent = MSG_DROP + ' ' + cell.getAttribute('data-d'); }
  else live.textContent = MSG_DROP;
}

// ── 포인터 ──
grid.addEventListener('pointerdown', function (e) {
  var chip = e.target.closest ? e.target.closest('.dd__chip') : null;
  if (!chip) return;
  root.classList.remove('is-demo');
  drag = { chip: chip, x: e.clientX, y: e.clientY, over: null };
  chip.classList.add('is-grab');
  chip.setAttribute('aria-grabbed', 'true');
  armCells(true);
  live.textContent = MSG_GRAB;
  e.preventDefault();
});
document.addEventListener('pointermove', function (e) {
  if (!drag) return;
  drag.chip.style.transform = 'translate(' + (e.clientX - drag.x) + 'px,' + (e.clientY - drag.y - 6) + 'px) scale(1.06) rotate(-4deg)';
  var el = document.elementFromPoint(e.clientX, e.clientY);
  var c = el && el.closest ? el.closest('.dd__c') : null;
  if (c !== drag.over) {
    if (drag.over) drag.over.classList.remove('is-over');
    drag.over = c;
    if (c) c.classList.add('is-over');
  }
});
document.addEventListener('pointerup', function () {
  if (!drag) return;
  var chip = drag.chip, cell = drag.over;
  chip.style.transform = '';
  chip.classList.remove('is-grab');
  chip.setAttribute('aria-grabbed', 'false');
  armCells(false);
  drop(chip, cell);
  drag = null;
  chip.focus({ preventScroll: true });
});

// ── 키보드 ──
grid.addEventListener('keydown', function (e) {
  var chip = e.target.closest ? e.target.closest('.dd__chip') : null;
  if (!chip) return;
  if (e.key === ' ' || e.key === 'Enter') {
    e.preventDefault();
    root.classList.remove('is-demo');
    if (held === chip) {
      drop(chip, cells[cur]);
      chip.classList.remove('is-grab');
      chip.setAttribute('aria-grabbed', 'false');
      armCells(false);
      held = null;
      chip.focus({ preventScroll: true });
    } else {
      held = chip;
      cur = cells.indexOf(chip.parentNode);
      chip.classList.add('is-grab');
      chip.setAttribute('aria-grabbed', 'true');
      armCells(true);
      cells[cur].classList.add('is-over');
      live.textContent = MSG_GRAB;
    }
    return;
  }
  if (e.key === 'Escape' && held === chip) {
    chip.classList.remove('is-grab');
    chip.setAttribute('aria-grabbed', 'false');
    armCells(false);
    held = null;
    return;
  }
  if (held !== chip) return;
  var n = cur;
  if (e.key === 'ArrowLeft') n = cur - 1;
  else if (e.key === 'ArrowRight') n = cur + 1;
  else if (e.key === 'ArrowUp') n = cur - COLS;
  else if (e.key === 'ArrowDown') n = cur + COLS;
  else return;
  if (n < 0 || n >= cells.length) return;
  e.preventDefault();
  cells[cur].classList.remove('is-over');
  cur = n;
  cells[cur].classList.add('is-over');
  live.textContent = cells[cur].getAttribute('data-d');
});

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

export type DragDropEvent = { id: string; title: string; day: number };

export type DragDropCalendarProps = {
  /** 칸에 붙일 날짜 라벨 (3행 × 5열 = 15칸) */
  days?: number[];
  events?: DragDropEvent[];
  today?: number;
  duration?: number;
  easing?: string;
  color?: string;
  onMove?: (id: string, day: number) => void;
  /** aria-live 안내 문구 — 언어팩에서 넣는다 */
  labels?: { grabbed: string; dropped: string };
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type KeyEvt = { key: string; preventDefault: () => void };
type PtrEvt = { clientX: number; clientY: number; preventDefault: () => void };

const COLS = 5;
const DEFAULT_DAYS = [7, 8, 9, 10, 11, 14, 15, 16, 17, 18, 21, 22, 23, 24, 25];
const DEFAULT_EVENTS: DragDropEvent[] = [
  { id: "a", title: "리뷰", day: 8 },
  { id: "b", title: "배포", day: 16 },
  { id: "c", title: "회고", day: 24 },
];

function Grip() {
  return (
    <span className={styles.grip} aria-hidden="true">
      <svg xmlns="http://www.w3.org/2000/svg" width="9" height="9" viewBox="0 0 256 256">
        <g fill="currentColor">
          <path d="M208 32v192a16 16 0 0 1-16 16H64a16 16 0 0 1-16-16V32a16 16 0 0 1 16-16h128a16 16 0 0 1 16 16" opacity=".2" />
          <path d="M104 60a12 12 0 1 1-12-12a12 12 0 0 1 12 12m60 12a12 12 0 1 0-12-12a12 12 0 0 0 12 12m-72 44a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12m-72 68a12 12 0 1 0 12 12a12 12 0 0 0-12-12m72 0a12 12 0 1 0 12 12a12 12 0 0 0-12-12" />
        </g>
      </svg>
    </span>
  );
}

export default function DragDropCalendar({
  days = DEFAULT_DAYS,
  events = DEFAULT_EVENTS,
  today = 15,
  duration = 220,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#2f6df6",
  onMove,
  labels = { grabbed: "집었습니다", dropped: "놓았습니다" },
}: DragDropCalendarProps) {
  const [placed, setPlaced] = useState<DragDropEvent[]>(events);
  const [grabbed, setGrabbed] = useState<string | null>(null);
  const [over, setOver] = useState<number>(-1);
  const [offset, setOffset] = useState<{ x: number; y: number } | null>(null);
  const [say, setSay] = useState("");
  const chipRefs = useRef<{ [id: string]: HTMLButtonElement | null }>({});
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  useEffect(() => {
    if (!grabbed) return;
    const el = chipRefs.current ? chipRefs.current[grabbed] : null;
    if (el) el.focus({ preventScroll: true });
  }, [grabbed]);

  function place(id: string, day: number) {
    setPlaced((ps) => ps.map((p) => (p.id === id ? { ...p, day } : p)));
    setSay(`${labels.dropped} ${day}`);
    if (onMove) onMove(id, day);
  }

  function dayFromPoint(x: number, y: number): number {
    const el = document.elementFromPoint(x, y);
    const cell = el && (el as HTMLElement).closest ? (el as HTMLElement).closest("[data-day]") : null;
    return cell ? Number((cell as HTMLElement).dataset.day) : -1;
  }

  function onPointerDown(id: string, e: PtrEvt) {
    e.preventDefault();
    setGrabbed(id);
    setSay(labels.grabbed);
    const x0 = e.clientX;
    const y0 = e.clientY;
    setOffset({ x: 0, y: 0 });
    let last = -1;
    const onMovePtr = (ev: { clientX: number; clientY: number }) => {
      setOffset({ x: ev.clientX - x0, y: ev.clientY - y0 });
      last = dayFromPoint(ev.clientX, ev.clientY);
      setOver(last);
    };
    const onUp = () => {
      document.removeEventListener("pointermove", onMovePtr);
      document.removeEventListener("pointerup", onUp);
      if (last >= 0) place(id, last);
      setGrabbed(null);
      setOver(-1);
      setOffset(null);
    };
    document.addEventListener("pointermove", onMovePtr);
    document.addEventListener("pointerup", onUp);
  }

  function onKeyDown(id: string, day: number, e: KeyEvt) {
    if (e.key === " " || e.key === "Enter") {
      e.preventDefault();
      if (grabbed === id) {
        if (over >= 0) place(id, days[over]);
        setGrabbed(null);
        setOver(-1);
      } else {
        setGrabbed(id);
        setOver(days.indexOf(day));
        setSay(labels.grabbed);
      }
      return;
    }
    if (e.key === "Escape" && grabbed === id) { setGrabbed(null); setOver(-1); return; }
    if (grabbed !== id || over < 0) return;
    let n = over;
    if (e.key === "ArrowLeft") n = over - 1;
    else if (e.key === "ArrowRight") n = over + 1;
    else if (e.key === "ArrowUp") n = over - COLS;
    else if (e.key === "ArrowDown") n = over + COLS;
    else return;
    if (n < 0 || n >= days.length) return;
    e.preventDefault();
    setOver(n);
    setSay(String(days[n]));
  }

  const rows: number[][] = [];
  for (let r = 0; r * COLS < days.length; r += 1) rows.push(days.slice(r * COLS, r * COLS + COLS));

  return (
    <div className={styles.dd} style={vars}>
      <div className={styles.head}>
        <span className={styles.title}>2026. 9</span>
        <span className={styles.live} role="status" aria-live="polite">{say}</span>
      </div>
      <div className={styles.grid} role="grid">
        {rows.map((row) => (
          <div className={styles.row} role="row" key={row[0]}>
            {row.map((d) => {
              const i = days.indexOf(d);
              const isOver = grabbed !== null && over === i;
              return (
                <div
                  key={d}
                  data-day={d}
                  className={`${styles.cell} ${isOver ? styles.isOver : ""}`}
                  role="gridcell"
                  aria-current={d === today ? "date" : undefined}
                  aria-dropeffect={grabbed ? "move" : undefined}
                >
                  <span className={`${styles.n} ${d === today ? styles.isToday : ""}`}>{d}</span>
                  {placed.filter((p) => p.day === d).map((p) => {
                    const held = grabbed === p.id;
                    const style: CSSProperties = held && offset
                      ? { transform: `translate(${offset.x}px, ${offset.y - 6}px) scale(1.06) rotate(-4deg)` }
                      : {};
                    return (
                      <button
                        key={p.id}
                        ref={(el: HTMLButtonElement | null) => { if (chipRefs.current) chipRefs.current[p.id] = el; }}
                        type="button"
                        className={`${styles.chip} ${held ? styles.isGrab : ""}`}
                        style={style}
                        aria-grabbed={held}
                        onPointerDown={(e: PtrEvt) => onPointerDown(p.id, e)}
                        onKeyDown={(e: KeyEvt) => onKeyDown(p.id, d, e)}
                      >
                        <Grip />
                        <span className={styles.t}>{p.title}</span>
                      </button>
                    );
                  })}
                </div>
              );
            })}
          </div>
        ))}
      </div>
    </div>
  );
}