単一リストの並べ替え

<%# sortable: markup-level composition — pointer-drag on each item emits the drag
    signal (with its keyboard alternative), roving keeps the handles one Tab stop,
    and sortable interprets the signal: it live-reorders the DOM, hands each step
    to the page's shared announcer (wording from the announce-* values), and
    dispatches reorder on a drop that changed the position. demo.js mirrors that
    reorder event into the "saved" line — the pattern a real app uses to POST the
    new position — and echoes what the announcer heard into a muted line. %>
<div class="sortable-demo">
  <p class="sortable-demo__hint"><%= t("components.sortable.demo.hint") %></p>
  <% announce = t("components.sortable.demo.announce") %>
  <div data-controller="stimeo--sortable"
       data-stimeo--sortable-announce-grabbed-text-value="<%= announce[:grabbed] %>"
       data-stimeo--sortable-announce-moved-text-value="<%= announce[:moved] %>"
       data-stimeo--sortable-announce-dropped-text-value="<%= announce[:dropped] %>"
       data-stimeo--sortable-announce-canceled-text-value="<%= announce[:canceled] %>">
    <ul class="sortable-demo__list" data-stimeo--sortable-target="list"
        data-controller="stimeo--roving"
        data-stimeo--roving-orientation-value="vertical"
        aria-label="<%= t('components.sortable.demo.list_label') %>">
      <% t("components.sortable.demo.items").each do |label| %>
        <li class="sortable-demo__item" data-stimeo--sortable-target="item"
            data-stimeo--sortable-name="<%= label %>"
            data-controller="stimeo--pointer-drag"
            data-stimeo--pointer-drag-axis-value="y">
          <button type="button" class="sortable-demo__handle"
                  aria-label="<%= t('components.sortable.demo.handle_label', name: label) %>"
                  data-stimeo--pointer-drag-target="handle"
                  data-stimeo--roving-target="item">
            <svg class="demo-icon" viewBox="0 0 24 24" fill="currentColor" stroke="none"
                 aria-hidden="true">
              <circle cx="9" cy="6" r="1.5"></circle><circle cx="15" cy="6" r="1.5"></circle>
              <circle cx="9" cy="12" r="1.5"></circle><circle cx="15" cy="12" r="1.5"></circle>
              <circle cx="9" cy="18" r="1.5"></circle><circle cx="15" cy="18" r="1.5"></circle>
            </svg>
          </button>
          <span class="sortable-demo__label"><%= label %></span>
        </li>
      <% end %>
    </ul>
  </div>
  <p class="sortable-demo__status" data-sortable-heard aria-hidden="true"></p>
  <p class="sortable-demo__saved" data-sortable-saved aria-live="polite"
     data-saved-template="<%= t("components.sortable.demo.saved_template") %>"></p>
</div>

/*
 * Presentation-only styles for the sortable demo. The library moves the real DOM
 * nodes and flips the data hooks; this CSS lays the rows out and makes the two
 * transient states visible — data-dragging / data-grabbed on the item (from
 * pointer-drag) highlight the row being moved.
 */

.sortable-demo {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: flex-start;
}

.sortable-demo__hint {
  margin: 0;
  color: var(--muted);
}

.sortable-demo__list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin: 0;
  padding: 0;
  list-style: none;
  min-width: 16rem;
}

.sortable-demo__item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 0.375rem;
  background: var(--bg);
}

/* The row in flight: pointer drag (data-dragging) or keyboard grab (data-grabbed). */
.sortable-demo__item[data-dragging],
.sortable-demo__item[data-grabbed] {
  border-color: var(--accent);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

.sortable-demo__handle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.25rem;
  border: 1px solid transparent;
  border-radius: 0.25rem;
  background: transparent;
  color: var(--muted);
  cursor: grab;
}

.sortable-demo__handle:hover {
  color: var(--accent-700);
}

.sortable-demo__handle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.sortable-demo__item[data-dragging] .sortable-demo__handle {
  cursor: grabbing;
}

.sortable-demo__handle .demo-icon {
  width: 1rem;
  height: 1rem;
}

.sortable-demo__status,
.sortable-demo__saved {
  margin: 0;
  min-height: 1.25rem;
  font-size: 0.9rem;
  color: var(--muted);
}

// sortable dispatches reorder only when a drop changed the position — the hook a
// real app uses to persist (POST the new index, or requestSubmit a form). This
// demo mirrors it into the "saved" line instead; copy comes from the localized
// data-* template (values only, never words).
const sortable = document.querySelector("[data-controller~='stimeo--sortable']");
const saved = document.querySelector("[data-sortable-saved]");
const heard = document.querySelector("[data-sortable-heard]");

sortable?.addEventListener("stimeo--sortable:reorder", (event) => {
  const { from, to } = event.detail;
  const template = saved?.dataset.savedTemplate || "{from} -> {to}";
  if (saved) {
    saved.textContent = template
      .replace("{from}", String(from + 1))
      .replace("{to}", String(to + 1));
  }
});

// The library carries no live region of its own: each step is handed to the
// page's shared stimeo--announcer, which is what a screen reader reads. This
// line shows the same message so the demo is followable by eye; aria-hidden on
// it keeps assistive tech from hearing the text twice.
window.addEventListener("stimeo--announcer:announce", (event) => {
  if (heard) heard.textContent = event.detail.message;
});