アンカー配置ユーティリティ

<%# Anchored positioning demo: the panel is positioned against the anchor button by the
    opt-in stimeo--anchored controller (it writes only position/left/top). Choose a side
    with the buttons — demo.js sets the placement value — and the panel mirrors the
    resolved side via data-anchored-placement (shown through demo.css). The controller is
    registered from the opt-in stimeo-ui/positioning subpath in demo.js; demo.css owns the
    look. %>
<div class="anchored-demo">
  <p class="anchored-demo__hint"><%= t("components.anchored.demo.hint") %></p>
  <div class="anchored-demo__controls" role="group"
    aria-label="<%= t('components.anchored.demo.placement_label') %>">
    <button type="button" class="demo-trigger" data-placement="top" aria-pressed="false">
      <%= t("components.anchored.demo.placements.top") %>
    </button>
    <button type="button" class="demo-trigger" data-placement="right" aria-pressed="false">
      <%= t("components.anchored.demo.placements.right") %>
    </button>
    <button type="button" class="demo-trigger" data-placement="bottom" aria-pressed="true">
      <%= t("components.anchored.demo.placements.bottom") %>
    </button>
    <button type="button" class="demo-trigger" data-placement="left" aria-pressed="false">
      <%= t("components.anchored.demo.placements.left") %>
    </button>
  </div>
  <div class="anchored-demo__viewport">
    <div class="anchored-demo__scope" data-controller="stimeo--anchored"
      data-stimeo--anchored-placement-value="bottom"
      data-stimeo--anchored-offset-value="8"
      data-stimeo--anchored-padding-value="8">
      <button type="button" class="demo-trigger anchored-demo__anchor"
        data-stimeo--anchored-target="anchor">
        <%= t("components.anchored.demo.anchor") %>
      </button>
      <div class="anchored-demo__floating" data-stimeo--anchored-target="floating"
        data-placement-label="<%= t('components.anchored.demo.placement_prefix') %>"></div>
    </div>
  </div>
</div>

/*
 * Presentation-only styles for the anchored-positioning demo. The library writes only
 * position/left/top on the floating element and mirrors the resolved side onto
 * data-anchored-placement; this CSS frames the viewport (a positioned ancestor the
 * absolute coordinates resolve against), the anchor, and the floating panel — and shows
 * the resolved placement through the data-* hook.
 */

.anchored-demo {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: flex-start;
  width: 100%;
}

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

.anchored-demo__controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* Positioned ancestor: the engine's absolute coordinates resolve against this box. */
.anchored-demo__viewport {
  position: relative;
  display: grid;
  place-items: center;
  width: 100%;
  min-height: 16rem;
  border: 1px dashed var(--border);
  border-radius: 0.5rem;
}

/* The scope is layout-transparent so the anchor centers in the viewport grid and the
   floating element positions against the viewport, not an extra box. */
.anchored-demo__scope {
  display: contents;
}

.anchored-demo__floating {
  /* The engine sets position/left/top; everything here is look-only and themable.
     Start absolute so the panel never disrupts layout before the controller connects. */
  position: absolute;
  top: 0;
  left: 0;
  min-width: 7rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--accent);
  border-radius: 0.375rem;
  background: var(--bg);
  color: var(--fg);
  box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
}

/* Surface the resolved (post-flip) placement from the controller's data-* hook. The
   label comes from a data-* attribute so it follows the page locale; only the
   placement value itself is API vocabulary and stays as the engine resolved it. */
.anchored-demo__floating::after {
  content: attr(data-placement-label) " " attr(data-anchored-placement);
  color: var(--muted);
}

// anchored opt-in positioning demo (consumer-side JS).
//
// stimeo--anchored ships in the opt-in stimeo-ui/positioning subpath, so it is NOT
// auto-registered by registerStimeo (which keeps the core install zero-dependency).
// Importing the subpath here is what pulls in @floating-ui/dom; we register the
// controller on the playground's Stimulus app, then wire the placement buttons to the
// controller's placement value so picking a side re-positions the panel.
import { AnchoredController } from "stimeo-ui/positioning";

// Register once (Turbo can re-run this inline module on navigation).
if (window.Stimulus && !window.__stimeoAnchoredRegistered) {
  window.Stimulus.register("stimeo--anchored", AnchoredController);
  window.__stimeoAnchoredRegistered = true;
}

document.querySelectorAll(".anchored-demo").forEach((root) => {
  // Idempotent: wire each root once even if this module re-runs. The marker is a property,
  // not an attribute: Turbo copies attributes into its page snapshot, so an attribute one
  // comes back set on a restored page whose elements carry no listeners.
  if (root.demoWired) return;
  root.demoWired = true;

  const scope = root.querySelector('[data-controller~="stimeo--anchored"]');
  if (!scope) return;
  const buttons = root.querySelectorAll("[data-placement]");

  buttons.forEach((button) => {
    button.addEventListener("click", () => {
      // Setting the value triggers placementValueChanged → the controller re-positions.
      scope.setAttribute("data-stimeo--anchored-placement-value", button.dataset.placement);
      buttons.forEach((other) => other.setAttribute("aria-pressed", String(other === button)));
    });
  });
});