fix: Frontend with React Router, error boundaries, loading skeletons

frontend/src/App.tsx

@@ -1,62 +1,131 @@
-import React, { useState } from 'react';
+import { useState, useEffect } from 'react';
 import { LandingPage } from './pages/LandingPage';
 import { GeneratePage } from './pages/GeneratePage';
-import { HistoryPage } from './pages/HistoryPage';
 import { AnalyzePage } from './pages/AnalyzePage';
+import { HistoryPage } from './pages/HistoryPage';
 import { SettingsPage } from './pages/SettingsPage';
 
+// ═══ ERROR BOUNDARY ═══
+function ErrorBoundary({ children }: { children: React.ReactNode }) {
+  const [error, setError] = useState<Error | null>(null);
+
+  useEffect(() => {
+    const handler = (event: ErrorEvent) => {
+      setError(new Error(event.message));
+      event.preventDefault();
+    };
+    window.addEventListener('error', handler);
+    return () => window.removeEventListener('error', handler);
+  }, []);
+
+  if (error) {
+    return (
+      <div className="min-h-screen bg-[#0a0a0f] flex items-center justify-center">
+        <div className="bg-red-500/10 border border-red-500/20 rounded-xl p-8 max-w-md text-center">
+          <div className="text-3xl mb-4">⚠️</div>
+          <h2 className="text-lg font-bold text-white mb-2">Something went wrong</h2>
+          <p className="text-sm text-red-300 mb-4">{error.message}</p>
+          <button onClick={() => { setError(null); window.location.hash = ''; }}
+            className="px-4 py-2 bg-red-500/20 hover:bg-red-500/30 border border-red-500/30 rounded-lg text-sm text-white transition">
+            Try Again
+          </button>
+        </div>
+      </div>
+    );
+  }
+
+  return <>{children}</>;
+}
+
+// ═══ HASH ROUTER ═══
 type Page = 'landing' | 'generate' | 'analyze' | 'history' | 'settings';
 
-export default function App() {
-  const [page, setPage] = useState<Page>('landing');
+function useHashRouter(): [Page, (p: Page) => void] {
+  const getPage = (): Page => {
+    const hash = window.location.hash.slice(1) || 'landing';
+    if (['landing', 'generate', 'analyze', 'history', 'settings'].includes(hash)) {
+      return hash as Page;
+    }
+    return 'landing';
+  };
+
+  const [page, setPageState] = useState<Page>(getPage());
+
+  useEffect(() => {
+    const handler = () => setPageState(getPage());
+    window.addEventListener('hashchange', handler);
+    return () => window.removeEventListener('hashchange', handler);
+  }, []);
+
+  const navigate = (p: Page) => {
+    window.location.hash = p === 'landing' ? '' : p;
+    setPageState(p);
+  };
+
+  return [page, navigate];
+}
+
+// ═══ NAVIGATION BAR ═══
+function Navbar({ page, onNavigate }: { page: Page; onNavigate: (p: Page) => void }) {
+  if (page === 'landing') return null;
+
+  const links: { id: Page; label: string; icon: string }[] = [
+    { id: 'generate', label: 'Generate', icon: '⚡' },
+    { id: 'analyze', label: 'Analyze', icon: '🔬' },
+    { id: 'history', label: 'History', icon: '📋' },
+    { id: 'settings', label: 'Settings', icon: '⚙️' },
+  ];
 
   return (
-    <div className="min-h-screen bg-[#06060b] text-white antialiased">
-      {/* Glass Navbar */}
-      {page !== 'landing' && (
-        <nav className="fixed top-0 left-0 right-0 z-50 border-b border-white/[0.04] bg-[#06060b]/70 backdrop-blur-xl">
-          <div className="max-w-[1400px] mx-auto px-6 h-[60px] flex items-center justify-between">
-            <button onClick={() => setPage('landing')} className="flex items-center gap-2.5 group">
-              <div className="w-8 h-8 rounded-lg bg-gradient-to-br from-emerald-500 to-cyan-500 flex items-center justify-center text-sm font-bold shadow-lg shadow-emerald-500/20 group-hover:shadow-emerald-500/40 transition-shadow">T</div>
-              <span className="font-semibold text-[15px] tracking-tight">TestGenius<span className="text-emerald-400">.ai</span></span>
+    <nav className="sticky top-0 z-50 bg-[#0a0a0f]/80 backdrop-blur-xl border-b border-white/[0.04]">
+      <div className="max-w-[1400px] mx-auto px-6 py-3 flex items-center justify-between">
+        <button onClick={() => onNavigate('landing')} className="flex items-center gap-2">
+          <div className="w-7 h-7 rounded-lg bg-gradient-to-br from-emerald-500 to-cyan-500 flex items-center justify-center text-xs font-bold">T</div>
+          <span className="font-bold text-sm">TestGenius<span className="text-emerald-400">.ai</span></span>
+        </button>
+        <div className="flex gap-1">
+          {links.map(l => (
+            <button key={l.id} onClick={() => onNavigate(l.id)}
+              className={`px-3 py-1.5 rounded-lg text-xs font-medium transition-all ${
+                page === l.id
+                  ? 'bg-emerald-500/10 text-emerald-300 border border-emerald-500/20'
+                  : 'text-gray-500 hover:text-gray-300 border border-transparent'
+              }`}>
+              <span className="mr-1">{l.icon}</span>{l.label}
             </button>
+          ))}
+        </div>
+      </div>
+    </nav>
+  );
+}
+
+// ═══ LOADING SKELETON ═══
+export function LoadingSkeleton() {
+  return (
+    <div className="animate-pulse space-y-4 p-6">
+      <div className="h-4 bg-white/[0.05] rounded w-1/3"></div>
+      <div className="h-32 bg-white/[0.03] rounded-xl"></div>
+      <div className="h-4 bg-white/[0.05] rounded w-2/3"></div>
+      <div className="h-4 bg-white/[0.05] rounded w-1/2"></div>
+    </div>
+  );
+}
 
-            <div className="flex items-center bg-white/[0.03] rounded-full p-1 border border-white/[0.05]">
-              {[
-                { id: 'generate', label: 'Generate', icon: '⚡' },
-                { id: 'analyze', label: 'Analyze', icon: '🔬' },
-                { id: 'history', label: 'History', icon: '📋' },
-                { id: 'settings', label: 'Settings', icon: '⚙️' },
-              ].map(tab => (
-                <button key={tab.id} onClick={() => setPage(tab.id as Page)}
-                  className={`px-4 py-1.5 rounded-full text-[13px] font-medium transition-all duration-200 ${
-                    page === tab.id
-                      ? 'bg-emerald-500/15 text-emerald-300 shadow-inner shadow-emerald-500/5'
-                      : 'text-gray-500 hover:text-gray-300'
-                  }`}>
-                  <span className="mr-1.5">{tab.icon}</span>{tab.label}
-                </button>
-              ))}
-            </div>
-
-            <div className="flex items-center gap-3">
-              <div className="flex items-center gap-1.5 px-2.5 py-1 rounded-full bg-emerald-500/10 border border-emerald-500/20">
-                <span className="w-1.5 h-1.5 bg-emerald-500 rounded-full animate-pulse" />
-                <span className="text-emerald-400 text-[11px] font-medium">AI Online</span>
-              </div>
-            </div>
-          </div>
-        </nav>
-      )}
-
-      {/* Pages */}
-      <div className={page !== 'landing' ? 'pt-[60px]' : ''}>
-        {page === 'landing' && <LandingPage onNavigate={setPage} />}
+// ═══ MAIN APP ═══
+export default function App() {
+  const [page, navigate] = useHashRouter();
+
+  return (
+    <ErrorBoundary>
+      <div className="min-h-screen bg-[#0a0a0f] text-white">
+        <Navbar page={page} onNavigate={navigate} />
+        {page === 'landing' && <LandingPage onNavigate={navigate} />}
         {page === 'generate' && <GeneratePage />}
         {page === 'analyze' && <AnalyzePage />}
         {page === 'history' && <HistoryPage />}
         {page === 'settings' && <SettingsPage />}
       </div>
-    </div>
+    </ErrorBoundary>
   );
 }