import { useMemo, useRef } from 'react';
import { useLocation } from 'react-router';
import { ImpersonationBanner, useDock, usePanelFullscreen, useChatNotifications } from 'officerdev';
import { usePermissions } from 'hooks/usePermissions';
import { ErrorBoundary } from '@/components/ErrorBoundary';
import { ScreenErrorFallback } from './ScreenErrorFallback';
import { Background } from './Background';
import { Header } from './Header';
import { Dock, useDockItems, defaultDockPaths } from './Dock';
import { Spotlight } from './Spotlight/Spotlight';
import { ShortcutsModal } from './ShortcutsModal';
import { useIsTouch } from './useIsTouch';
import { usePageTitleSync } from '@/state/usePageTitle';
import { RouteGate } from './RouteGate';

type DashboardLayoutProps = {
  children?: React.ReactNode;
};
export function DashboardLayout({ children }: DashboardLayoutProps) {
  const { canVisit, plugins } = usePermissions();
  // Filtered BEFORE useDock, so a member's saved dock order cannot resurrect an icon their role no longer
  // reaches, and so the pinned-item defaults fall back to something they can actually open. Cosmetic
  // either way — every one of these routes is refused server-side too — but an app that offers a door it
  // will then slam is worse than one that never showed it.
  // The shell's own items plus whatever the installed sidecars contribute. `plugins` already excludes
  // anything uninstalled or disabled, so an absent feature has no tile at all rather than a dead one.
  const allDockItems = useDockItems(plugins);
  const permitted = useMemo(() => allDockItems.filter((item) => canVisit(item.to)), [canVisit, allDockItems]);
  const { items: visibleItems } = useDock(
    permitted,
    useMemo(() => defaultDockPaths(plugins), [plugins]),
  );
  const isTouch = useIsTouch();
  const { pathname } = useLocation();
  usePageTitleSync();
  useChatNotifications();
  // A panel can maximize into the content region on its own, but it cannot paint over this header — the
  // region below is an `absolute z-2` stacking context and the header is a `fixed z-10` sibling of it. So
  // "full screen" is cooperative: the panel asks, and the chrome steps aside.
  const panelFullscreen = usePanelFullscreen();
  // The nav dock measures its reveal boundary from this element, so it sits just above whatever is at the
  // bottom of the content region. Written for the in-flow music bar, which used to be rendered here and
  // left with `plugins/music/` on 2026-08-15; the measurement is not music-specific and still holds for
  // anything a screen puts at its foot.
  const regionRef = useRef<HTMLElement | null>(null);

  return (
    <div className="relative flex h-dvh flex-col overflow-hidden outline-none inset-0">
      {/* ABOVE the header, and outside everything that can be hidden. A fullscreen panel hides the header;
          it must not be able to hide the fact that you are somebody else. Renders nothing when you are not. */}
      <ImpersonationBanner />
      <Header dockItems={visibleItems} hidden={panelFullscreen} />
      {/* Outside the content region on purpose, like the header and the dock: whatever a screen is doing
          — maximised panel, error boundary, mid-navigation — ctrl-space still gets you off it. */}
      <Spotlight />
      {/* Outside the content region for the same reason Spotlight is: ctrl+? has to work from a maximised
          panel, an error boundary, or mid-navigation. */}
      <ShortcutsModal />
      {/* overflow-CLIP, not hidden: `hidden` still makes this a scroll container, and the nav Dock —
          absolute, parked below the bottom edge by translateY while hidden — adds its transformed box to
          the scrollable overflow. So clicking a link let the browser scroll this section ~70px to reveal
          the focused element: content slid up under the fixed header and the hidden dock slid into view.
          `clip` clips identically but is not scrollable, so nothing can ever scroll it. */}
      <section ref={regionRef} className="relative min-h-0 flex-1 snap-start overflow-clip">
        <Background />
        {!isTouch && <Dock items={visibleItems} boundaryRef={regionRef} className="hidden md:flex" />}
        <div className="absolute inset-0 z-2 pt-[52px] md:pt-[64px] pb-2 overflow-y-auto">
          {/* Chrome stays outside: whatever broke, the dock and the header still navigate you off it.
              Keyed on the pathname so leaving a broken screen is itself a recovery. */}
          <ErrorBoundary
            resetKeys={[pathname]}
            fallback={({ error, reset }) => <ScreenErrorFallback error={error} reset={reset} />}
          >
            {/* Inside the boundary and around every screen, so one place decides whether a route exists for
                this account on this server. Filtering the dock was never enough: the tile was hidden and the
                route still rendered for anyone who typed it, followed an old link or restored a tab. */}
            <RouteGate>{children}</RouteGate>
          </ErrorBoundary>
        </div>
      </section>
    </div>
  );
}