// Collapsible chrome controller: left sidebar + right companion rail.
// Desktop → panels shrink the grid (state persisted). Narrow/portrait → panels
// become off-canvas drawers over the main area with a scrim; closed by default.
//
// State lives as classes on #shell: `sidebar-collapsed` / `rail-collapsed`.
// rightrail.js also toggles `rail-collapsed` (its own strip) + the same key, so
// a MutationObserver keeps the scrim in sync no matter who toggles.

const SB_KEY = 'void_sidebar_collapsed';
const RAIL_KEY = 'void_rail_collapsed';

const shell = () => document.getElementById('shell');
const isNarrow = () => window.matchMedia('(max-width: 860px)').matches;

function syncScrim() {
  const s = shell();
  if (!s) return;
  const anyOpen = isNarrow() &&
    (!s.classList.contains('sidebar-collapsed') || !s.classList.contains('rail-collapsed'));
  document.body.classList.toggle('drawer-open', anyOpen);
}

export function toggleSidebar() {
  const s = shell();
  const opening = s.classList.contains('sidebar-collapsed');
  s.classList.toggle('sidebar-collapsed');
  if (opening && isNarrow()) s.classList.add('rail-collapsed'); // one drawer at a time
  if (!isNarrow()) localStorage.setItem(SB_KEY, String(!opening));
}

export function toggleRail() {
  const s = shell();
  const opening = s.classList.contains('rail-collapsed');
  s.classList.toggle('rail-collapsed');
  if (opening && isNarrow()) s.classList.add('sidebar-collapsed');
  localStorage.setItem(RAIL_KEY, String(!opening));
}

function closeDrawers() {
  shell().classList.add('sidebar-collapsed', 'rail-collapsed');
}

export function initChrome() {
  const s = shell();
  if (!s) return;

  if (!document.getElementById('scrim')) {
    const scrim = document.createElement('div');
    scrim.id = 'scrim';
    scrim.addEventListener('click', closeDrawers);
    document.body.appendChild(scrim);
  }

  // Initial state.
  if (isNarrow()) {
    s.classList.add('sidebar-collapsed', 'rail-collapsed'); // drawers closed on phones/portrait
  } else if (localStorage.getItem(SB_KEY) === 'true') {
    s.classList.add('sidebar-collapsed'); // restore desktop preference (rail handled by rightrail.js)
  }

  // Keep the scrim correct whenever shell classes change (covers rightrail's own toggle).
  new MutationObserver(syncScrim).observe(s, { attributes: true, attributeFilter: ['class'] });

  // Crossing the breakpoint: collapse to a sane default for the new mode.
  let wasNarrow = isNarrow();
  window.addEventListener('resize', () => {
    const narrow = isNarrow();
    if (narrow === wasNarrow) return;
    wasNarrow = narrow;
    if (narrow) closeDrawers();
    else s.classList.remove('sidebar-collapsed'); // show the sidebar again on desktop
    syncScrim();
  });

  syncScrim();
}