import { useEffect, useState } from 'react';
import { Navigate, Route, Routes } from 'react-router-dom';

import { RequireAnonymous, RequireAuth, RequireSiteAdmin } from './auth/guards';
import { PondGraphPage } from './graph/PondGraphPage';
import { MAINTENANCE_EVENT } from './lib/api';
import { MaintenancePage } from './pages/MaintenancePage';
import { AppLayout } from './layout/AppLayout';
import { AdminSettingsPage } from './pages/AdminSettingsPage';
import { AdminSystemPage } from './pages/AdminSystemPage';
import { FontCatalogPage } from './pages/FontCatalogPage';
import { HomePage } from './pages/HomePage';
import { LegalPage } from './pages/LegalPage';
import { NotFoundPage } from './pages/NotFoundPage';
import { PageEditorPage } from './pages/PageEditorPage';
import { PluginPreviewPage } from './pages/PluginPreviewPage';
import { PondHomePage } from './pages/PondHomePage';
import { PondSettingsPage } from './pages/PondSettingsPage';
import { PublicPageView } from './pages/PublicPageView';
import { SettingsPage } from './pages/SettingsPage';
import { TrashPage } from './pages/TrashPage';
import { ForgotPasswordPage } from './pages/auth/ForgotPasswordPage';
import { LoginPage } from './pages/auth/LoginPage';
import { ResetPasswordPage } from './pages/auth/ResetPasswordPage';
import { SignupPage } from './pages/auth/SignupPage';
import { VerifyEmailPage } from './pages/auth/VerifyEmailPage';
import { SetupPendingPage } from './setup/SetupPendingPage';
import { SetupWizardPage } from './setup/SetupWizardPage';
import { useSetupStatus } from './setup/use-setup-status';

export function App(): React.JSX.Element {
  const setup = useSetupStatus();

  // Maintenance gate (issue #103): once any api call answers 503
  // maintenance_mode — a backup restore is running — the whole UI becomes
  // the maintenance screen, which polls the exempt status endpoint and
  // reloads when the instance is back.
  const [maintenance, setMaintenance] = useState(false);
  useEffect(() => {
    const onMaintenance = (): void => setMaintenance(true);
    window.addEventListener(MAINTENANCE_EVENT, onMaintenance);
    return () => window.removeEventListener(MAINTENANCE_EVENT, onMaintenance);
  }, []);
  if (maintenance) return <MaintenancePage />;

  // First-run gate (issue #81): while setup is pending the api 503s almost
  // everything, so the SPA offers only the wizard, the login (to resume a
  // started wizard as the Site Admin), and a pending notice — without the
  // regular chrome, whose pond/search queries would all fail. If the status
  // probe itself fails (offline reload, #38), fall through to the app.
  if (setup.isPending) return <></>;
  if (setup.data?.status === 'required') {
    return (
      <div className="setup-shell">
        <Routes>
          <Route path="setup" element={<SetupWizardPage />} />
          <Route path="login" element={<LoginPage />} />
          <Route path="*" element={<SetupPendingPage />} />
        </Routes>
      </div>
    );
  }

  return (
    <Routes>
      <Route element={<AppLayout />}>
        <Route index element={<HomePage />} />

        <Route element={<RequireAnonymous />}>
          <Route path="login" element={<LoginPage />} />
          <Route path="signup" element={<SignupPage />} />
          <Route path="forgot-password" element={<ForgotPasswordPage />} />
        </Route>
        {/* Verify/reset work regardless of session state (mail links). */}
        <Route path="verify-email" element={<VerifyEmailPage />} />
        <Route path="reset-password" element={<ResetPasswordPage />} />
        {/* Public read-only page view — reachable without a session (issue #56). */}
        <Route path="public/:pondSlug/:pageSlug" element={<PublicPageView />} />
        {/* Legal pages — public, no session required (issue #82). */}
        <Route path="legal/:kind" element={<LegalPage />} />
        {/* Setup is done exactly once — afterwards the wizard url just goes home. */}
        <Route path="setup" element={<Navigate to="/" replace />} />

        <Route element={<RequireAuth />}>
          <Route path="settings" element={<SettingsPage />} />
          <Route path="fonts" element={<FontCatalogPage />} />
          <Route path="p/:pondSlug" element={<PondHomePage />} />
          {/* Static segment "trash" wins react-router's ranking over the
              dynamic :pageSlug sibling below — a page slugged "trash"
              would be unreachable via direct URL, an accepted v1 gap. */}
          <Route path="p/:pondSlug/trash" element={<TrashPage />} />
          {/* Static "settings" wins over :pageSlug, like "trash" above. */}
          <Route path="p/:pondSlug/settings" element={<PondSettingsPage />} />
          {/* Static "graph" wins over :pageSlug, like "trash" above (#112). */}
          <Route path="p/:pondSlug/graph" element={<PondGraphPage />} />
          <Route path="p/:pondSlug/:pageSlug" element={<PageEditorPage />} />
        </Route>
        <Route element={<RequireSiteAdmin />}>
          <Route path="admin" element={<AdminSettingsPage />} />
          <Route path="admin/system" element={<AdminSystemPage />} />
          {/* Sandbox preview of one installed plugin (issue #73). */}
          <Route path="admin/plugins/:pluginId/preview" element={<PluginPreviewPage />} />
        </Route>

        <Route path="*" element={<NotFoundPage />} />
      </Route>
    </Routes>
  );
}