// Shared async-button primitive. Used by both the dashboard and the
// per-agent UI for any button that triggers a network action.
//
// `asyncBtn(btn, fn)` — the single reusable component:
//   1. Guards double-click: returns immediately if `btn` is already
//      disabled (prevents a second identical request from firing).
//   2. Saves `btn.innerHTML` and replaces it with a spinner during the
//      async operation.
//   3. Re-enables the button and restores the original content when `fn`
//      resolves or rejects (via `finally`), so callers don't need
//      save/restore boilerplate.
//
// Usage:
//   btn.addEventListener('click', () => asyncBtn(btn, async () => {
//     const resp = await fetch('/api/...');
//     if (!resp.ok) throw new Error(await resp.text());
//     // handle success
//   }));
//
// Error handling: `asyncBtn` restores the button on any thrown error /
// rejected promise but does NOT surface the error — callers must catch
// and display it themselves (via `themedToast`, `alert`, a status span,
// etc.) inside `fn` without re-throwing. `fn` must not let errors escape
// unhandled: `asyncBtn` returns the `fn().finally(...)` promise so
// callers can optionally chain `.catch` or `await`, but does not add its
// own catch — an unhandled rejection from `fn` will propagate normally.
export function asyncBtn(btn, fn) {
  if (btn.disabled) return; // double-click guard
  const orig = btn.innerHTML;
  btn.disabled = true;
  btn.innerHTML = '<span class="spinner">◐</span>';
  return fn().finally(() => {
    btn.disabled = false;
    btn.innerHTML = orig;
  });
}