Extract IntroPage from app.tsx

docs/APP_REFACTORING_DESIGN.md

@@ -102,7 +102,7 @@ We will gradually eliminate React state variables in `src/app.tsx` and derive th
 #### Phase 4: Structural Page Nesting
 *   [x] **Step 4.1:** Create `src/hooks/use_google_auth.ts` to manage Google Drive authentication token updates. Remove `hasGoogleToken` state from `src/app.tsx`.
 *   [x] **Step 4.2:** Create `src/pages/view_page.tsx` containing layout rendering (`renderMainArea`), asynchronous data loaders, view state management, `revokeObjectUrls` cleanups, and `<GoogleAuthModal>` error fallback state and rendering.
-*   [ ] **Step 4.3:** Create `src/pages/intro_page.tsx` rendering the landing screen and its own local header.
+*   [x] **Step 4.3:** Create `src/pages/intro_page.tsx` rendering the landing screen and its own local header.
 *   [ ] **Step 4.4:** Refactor `src/app.tsx` to serve as a pure routing switch routing to `<IntroPage />` or `<ViewPage />`. In `App`, handle Google Drive redirection synchronously during the render pass by returning a `<Navigate replace />` element (preventing render flashing), and ensure the redirection parser checks both the router `location.search` and the external `window.location.search` to handle HashRouter query structure robustly. Once external parameters (like `state` or `authcode`) are detected, they must be stripped from `window.location.search` using `window.history.replaceState` to prevent redirection loops on page refresh. Remove all layout state logic from the root file, including moving the `useWebMcpBridge` hook invocation into `<ViewPage />`. Run final verification scripts (`npm run check:all`).
 
 ## Future Considerations

src/app.tsx

@@ -1,33 +1,20 @@
 import queryString from 'query-string';
-import {useEffect, useMemo, useRef} from 'react';
+import {useEffect, useRef} from 'react';
 import {Navigate, Route, Routes, useLocation, useNavigate} from 'react-router';
-import {
-  clearGoogleDriveCache,
-  googleDriveService,
-} from './datasource/google_drive_service';
-import {useGoogleAuth} from './hooks/use_google_auth';
-import {Intro} from './intro';
-import {TopBar} from './menu/top_bar';
+import {IntroPage} from './pages/intro_page';
 import {ViewPage} from './pages/view_page';
-import {getArguments, getStaticUrl} from './util/url_args';
+import {getStaticUrl} from './util/url_args';
 
 const staticUrl = getStaticUrl();
 
 /**
  * Root App component that orchestrates top-level routing, Google Drive "Open with"
- * payload interception and redirection, and global layout rendering for the intro view.
+ * payload interception and redirection.
  */
 export function App() {
-  /** Tracks whether the user has a valid cached Google Drive OAuth access token and provides a state setter. */
-  const {hasGoogleToken, setHasGoogleToken} = useGoogleAuth();
-
   const navigate = useNavigate();
   const location = useLocation();
 
-  const args = useMemo(() => getArguments(location), [location]);
-  /** Whether the app is in standalone mode, i.e. showing 'open file' menus. */
-  const standalone = args.standalone;
-
   /** Prevents the Google Drive "Open with" state from being processed more than once. */
   const stateProcessed = useRef(false);
 
@@ -68,14 +55,6 @@ export function App() {
     }
   }, [navigate, location.search]);
 
-  async function onGoogleSignOut() {
-    await googleDriveService.signOut();
-    setHasGoogleToken(false);
-    // Purge sessionStorage keys starting with "google-drive:"
-    clearGoogleDriveCache();
-    navigate({pathname: '/'}, {replace: true});
-  }
-
   const isViewPage = location.pathname === '/view';
 
   if (isViewPage) {
@@ -87,25 +66,14 @@ export function App() {
     );
   }
 
-  return (
-    <>
-      <TopBar
-        showingChart={false}
-        standalone={standalone}
-        hasGoogleToken={hasGoogleToken}
-        onGoogleSignOut={onGoogleSignOut}
-        onGoogleTokenAcquired={() => setHasGoogleToken(true)}
-      />
-      {staticUrl ? (
-        <Routes>
-          <Route path="*" element={<Navigate to="/view" replace />} />
-        </Routes>
-      ) : (
-        <Routes>
-          <Route path="/" element={<Intro />} />
-          <Route path="*" element={<Navigate to="/" replace />} />
-        </Routes>
-      )}
-    </>
+  return staticUrl ? (
+    <Routes>
+      <Route path="*" element={<Navigate to="/view" replace />} />
+    </Routes>
+  ) : (
+    <Routes>
+      <Route path="/" element={<IntroPage />} />
+      <Route path="*" element={<Navigate to="/" replace />} />
+    </Routes>
   );
 }

src/pages/intro_page.tsx

@@ -0,0 +1,43 @@
+import {useMemo} from 'react';
+import {useLocation, useNavigate} from 'react-router';
+import {
+  clearGoogleDriveCache,
+  googleDriveService,
+} from '../datasource/google_drive_service';
+import {useGoogleAuth} from '../hooks/use_google_auth';
+import {Intro} from '../intro';
+import {TopBar} from '../menu/top_bar';
+import {getArguments} from '../util/url_args';
+
+/**
+ * IntroPage component that represents the landing page of the application.
+ * It renders the intro text and lists examples alongside its own TopBar.
+ */
+export function IntroPage() {
+  const {hasGoogleToken, setHasGoogleToken} = useGoogleAuth();
+  const navigate = useNavigate();
+  const location = useLocation();
+
+  const args = useMemo(() => getArguments(location), [location]);
+  const standalone = args.standalone;
+
+  async function onGoogleSignOut() {
+    await googleDriveService.signOut();
+    setHasGoogleToken(false);
+    clearGoogleDriveCache();
+    navigate({pathname: '/'}, {replace: true});
+  }
+
+  return (
+    <>
+      <TopBar
+        showingChart={false}
+        standalone={standalone}
+        hasGoogleToken={hasGoogleToken}
+        onGoogleSignOut={onGoogleSignOut}
+        onGoogleTokenAcquired={() => setHasGoogleToken(true)}
+      />
+      <Intro />
+    </>
+  );
+}