// Generic async submit + spinner for any `<form data-async>`.
// Replaces the standard form-POST navigation: button shows a spinner during
// the request, `data-confirm` runs first (skips the action if cancelled),
// page reloads on success so the new state is reflected.
(() => {
  document.querySelectorAll('form[data-async]').forEach(form => {
    form.addEventListener('submit', async (e) => {
      e.preventDefault();
      if (form.dataset.confirm && !confirm(form.dataset.confirm)) return;
      const btn = form.querySelector('button[type="submit"], button:not([type]), .btn-inline');
      const original = btn ? btn.innerHTML : '';
      if (btn) {
        btn.disabled = true;
        btn.innerHTML = '<span class="spinner">◐</span>';
      }
      try {
        const resp = await fetch(form.action, {
          method: form.method || 'POST',
          body: new FormData(form),
          redirect: 'manual',
        });
        const ok = resp.ok
          || resp.type === 'opaqueredirect'
          || (resp.status >= 200 && resp.status < 400);
        if (!ok) {
          const text = await resp.text().catch(() => '');
          alert('action failed: ' + resp.status + (text ? '\n\n' + text : ''));
          if (btn) { btn.disabled = false; btn.innerHTML = original; }
          return;
        }
        window.location.reload();
      } catch (err) {
        alert('action failed: ' + err);
        if (btn) { btn.disabled = false; btn.innerHTML = original; }
      }
    });
  });
})();