// Pure routing helpers for the news feed, shared by its two mounts: `/` (interim,
// becomes the hub at cutover) and `/news` (its permanent home). Kept framework-free
// so they're unit-testable without mounting the Svelte component.

// Which base path the feed is rendering at. `/news` is permanent; `/` is the interim
// mount. Anything not under /news is treated as `/`.
export function feedBase(pathname) {
  return (pathname || '').startsWith('/news') ? '/news' : '/';
}

// The current view key, derived from query params only (path-agnostic, so a deep link
// works at either base): search > source > tag > explicit view > 'today' (Highlights).
export function parseView(url) {
  const p = url.searchParams;
  if ((p.get('q') || '').trim()) return 'search';
  if (p.get('source')) return 'source:' + p.get('source');
  if (p.get('tag')) return 'tag:' + p.get('tag');
  return p.get('view') || 'today';
}

// A link to a view at the given base path. 'today' is the bare base; everything else
// carries its query param so the same parseView() reads it back identically.
export function viewUrl(base, key) {
  if (key === 'today') return base;
  if (key.startsWith('source:')) return base + '?source=' + encodeURIComponent(key.slice(7));
  if (key.startsWith('tag:')) return base + '?tag=' + encodeURIComponent(key.slice(4));
  return base + '?view=' + encodeURIComponent(key);
}