/** Construct inert embed markup, retaining the read capability only in the URL fragment. */
export function viewerURL(value, token, base = location.origin) {
  const url = new URL(value, base);
  if (!['https:', 'http:'].includes(url.protocol)) throw new Error('Invalid viewer URL');
  if (url.username || url.password) throw new Error('Invalid viewer URL');
  if (token) url.hash = new URLSearchParams({ token }).toString();
  return url.href;
}
export function iframeCode(value, base = location.origin) {
  const url = viewerURL(value, null, base);
  const escaped = url.replace(/[&"<>']/g, c => ({'&':'&amp;','"':'&quot;','<':'&lt;','>':'&gt;',"'":'&#39;'}[c]));
  return `<iframe\n  src="${escaped}"\n  width="100%"\n  height="800"\n  title="Altium design viewer"\n  loading="lazy"\n  referrerpolicy="no-referrer"\n  allowfullscreen\n></iframe>`;
}
export function mountShare(host, value) {
  const code = iframeCode(value), widget = document.createElement('div');widget.className = 'share-widget';
  const toggle = document.createElement('button');toggle.type = 'button';toggle.className = 'share-toggle';toggle.textContent = 'Share';toggle.setAttribute('aria-expanded','false');
  const panel = document.createElement('div');panel.className = 'share-panel';panel.hidden = true;
  const caption = document.createElement('p');caption.textContent = 'Embed this viewer in Gitea or this service:';
  const text = document.createElement('textarea');text.readOnly = true;text.value = code;text.rows = 9;text.setAttribute('aria-label','Viewer iframe code');
  const note = document.createElement('p');note.className = 'share-note';
  note.textContent = new URL(value,location.origin).hash.includes('token=') ? 'This code includes a read token. Anyone with the code can view this design.' : 'Embedding is allowed only on this service and https://git.sadentel.net.';
  const copy = document.createElement('button');copy.type = 'button';copy.textContent = 'Copy iframe';
  const status = document.createElement('span');status.setAttribute('role','status');
  copy.addEventListener('click',async()=>{
    try { await navigator.clipboard.writeText(code);status.textContent = 'Copied'; }
    catch { text.focus();text.select();status.textContent = 'Select and copy the code manually.'; }
  });
  toggle.addEventListener('click',()=>{panel.hidden=!panel.hidden;toggle.setAttribute('aria-expanded',String(!panel.hidden));});
  widget.addEventListener('keydown',event=>{if(event.key==='Escape'){panel.hidden=true;toggle.setAttribute('aria-expanded','false');toggle.focus();}});
  panel.append(caption,text,note,copy,status);widget.append(toggle,panel);host.append(widget);
}