/**
 * Hash routing, shared.
 *
 * `pageFromHash()` turns `location.hash` into the page id the app navigates by
 * (`llm-page-change`'s `detail.page`, the sidebar's `_activePage`, the value the
 * view-context store describes). It lives here — and not in `sidebar.js`, where
 * it grew — because there are now two readers of it: the menu highlight and the
 * view context attached to a message. Two copies of this logic would drift, and
 * the drift would be invisible: the assistant would be told the user is on one
 * page while the menu highlights another.
 *
 * The mobile shell (`mobile-app.js`) routes a fixed set of sections of its own
 * and does not go through this.
 */

// Every hash segment the app accepts as a page. Anything else falls back to
// `home`, so a hand-typed or stale URL lands on the chat rather than nowhere.
export const KNOWN_PAGES = [
  'inbox', 'dashboard', 'tasks', 'projects', 'files', 'models', 'providers',
  'approval', 'agents', 'users', 'roles', 'shared-folders', 'connectors',
  'connector', 'plugins', 'plugin-detail', 'marketplace', 'profile', 'config',
  'llm-requests', 'session', 'system-agents', 'file_viewer', 'tool_detail',
];

export function pageFromHash() {
  const hash = location.hash.slice(1);
  if (!hash) return 'home';
  // Segment ends at the first `/` (e.g. `#session/123`) or `?` (e.g. `#file_viewer?path=...`).
  const match = hash.match(/^([^/?]+)/);
  const segment = match ? match[1] : '';
  // Plugin pages: `#plugin/<plugin_id>/<page_id>` — the route is accepted by
  // shape (deep links must survive the async `/api/plugins/pages` load); the
  // host reports an error if the page turns out not to exist for this user.
  if (segment === 'plugin') {
    const m = hash.match(/^plugin\/([^/?]+)\/([^/?]+)/);
    return m ? `plugin/${m[1]}/${m[2]}` : 'home';
  }
  // `connector` (singular) is the per-connector detail page, `connectors` the list.
  // `plugin-catalog` is the pre-merge hash of what is now `#plugins`.
  const page = segment === 'plugin-catalog' ? 'plugins' : segment;
  return KNOWN_PAGES.includes(page) ? page : 'home';
}