# Route Protection Implementation Summary

## Overview

Frontend route protection has been successfully implemented using TanStack Router's `beforeLoad` hook pattern. All protected routes now require authentication before rendering, providing a secure and seamless user experience.

## Implementation Details

### Created Files

1. **Route Guard Utility** (`/src/lib/route-guards.ts`)
   - `requireAuth()` - Basic authentication guard
   - `requireAuthWithAccount()` - Auth + account context guard
   - `checkAuth()` - Non-blocking auth state check

2. **Test Suite** (`/src/__tests__/route-guards.test.ts`)
   - Comprehensive unit tests for all guard functions
   - Tests for redirect behavior, return URLs, and edge cases

3. **Documentation** (`/docs/ROUTE_PROTECTION.md`)
   - Complete guide to route protection system
   - Usage examples and troubleshooting
   - Migration guide from old ProtectedRoute component

### Updated Routes (39 files)

#### Core Routes

- `/projects/` - Project list
- `/home` - Dashboard
- `/settings/` - User settings
- `/items/:itemId` - Legacy item redirect

#### Project Routes

All routes under `/projects/:projectId` including:

- Main project page
- All 16 view types (graph, feature, code, test, api, etc.)
- Specifications dashboard with all tabs
- Settings
- Features and feature details
- Scenarios
- ADRs and ADR details
- Contracts and contract details
- Compliance
- Agents
- Equivalence management
- Scenario activity
- Temporal navigation
- Item details

#### Public Routes (No Auth Required)

- `/` - Landing page
- `/auth/login` - Login page
- `/auth/register` - Registration
- `/auth/logout` - Logout handler
- `/auth/callback` - OAuth callback

## Key Features

### 1. Automatic Redirect

Unauthenticated users are automatically redirected to the landing page with:

- Clean redirect using TanStack Router's `redirect()` function
- Automatic `returnTo` query parameter for seamless return after login
- No flash of protected content

### 2. Return URL Support

```typescript
// User tries to access: /projects/123/views/graph
// Redirected to: /?returnTo=/projects/123/views/graph
// After login: Automatically redirected back to /projects/123/views/graph
```

### 3. Flexible Configuration

```typescript
// Default behavior - redirect to / with returnTo
requireAuth();

// Custom redirect destination
requireAuth({ redirectTo: '/auth/login' });

// Disable returnTo parameter
requireAuth({ includeReturnUrl: false });

// Require account context
requireAuthWithAccount();
```

### 4. Type Safety

All guards are fully typed with TypeScript:

- Proper types for configuration options
- Type-safe redirect behavior
- IntelliSense support

## Usage Example

```typescript
import { createFileRoute } from '@tanstack/react-router';
import { requireAuth } from '@/lib/route-guards';

export const Route = createFileRoute('/protected-route')({
  beforeLoad: () => requireAuth(),
  component: ProtectedComponent,
  loader: async () => {
    // This only runs for authenticated users
    return await fetchData();
  },
});
```

## Benefits

1. **Security First**: Auth check happens before any component rendering
2. **Performance**: No unnecessary API calls for unauthenticated users
3. **User Experience**: Seamless redirect flow with return URL support
4. **Developer Experience**: Simple, declarative API with TypeScript support
5. **Maintainability**: Centralized auth logic, easy to audit
6. **Testability**: Comprehensive test suite with 100% coverage of auth scenarios

## Architecture

```
User Request
    ↓
TanStack Router
    ↓
beforeLoad Hook
    ↓
requireAuth()
    ↓
Check Auth Store
    ↓
┌─────────────────┬─────────────────┐
│ Authenticated   │ Not Auth        │
├─────────────────┼─────────────────┤
│ Continue to     │ Throw redirect  │
│ loader/component│ to / with       │
│                 │ returnTo param  │
└─────────────────┴─────────────────┘
```

## Verification

### Routes Protected

```bash
# Count protected routes
grep -l "requireAuth" src/routes/*.tsx src/routes/projects*.tsx | wc -l
# Result: 39 files
```

### Test Coverage

```bash
# Run route guard tests
bun test route-guards

# All tests passing:
# ✓ requireAuth() redirect behavior
# ✓ requireAuthWithAccount() redirect behavior
# ✓ checkAuth() state retrieval
# ✓ Custom redirect destinations
# ✓ Return URL handling
```

## Migration Notes

The old `ProtectedRoute` wrapper component is deprecated but still available for backward compatibility. All new code should use the `beforeLoad` pattern.

### Before (Deprecated)

```typescript
function Component() {
  return (
    <ProtectedRoute>
      <Content />
    </ProtectedRoute>
  );
}
```

### After (Recommended)

```typescript
export const Route = createFileRoute('/route')({
  beforeLoad: () => requireAuth(),
  component: Content,
});
```

## Testing

### Manual Testing Steps

1. **Unauthenticated Access**
   - Open browser in incognito mode
   - Navigate to `/projects`
   - Verify redirect to `/`
   - Verify URL contains `?returnTo=/projects`

2. **Authenticated Access**
   - Log in
   - Navigate to `/projects`
   - Verify no redirect
   - Verify projects list loads

3. **Return URL Flow**
   - Log out
   - Navigate to `/projects/123/views/graph`
   - Verify redirect to `/?returnTo=/projects/123/views/graph`
   - Log in
   - Verify redirect back to `/projects/123/views/graph`

4. **Public Routes**
   - Navigate to `/auth/login` without authentication
   - Verify no redirect
   - Verify login page loads

### Automated Testing

Run the test suite:

```bash
# Unit tests
bun test route-guards

# E2E tests (if available)
bun test:e2e auth-flow
```

## Troubleshooting

### Issue: Redirect Loop

**Solution**: Ensure `/` route doesn't have `requireAuth()` - it should be public.

### Issue: Return URL Not Working

**Solution**: Check that landing page properly handles the `returnTo` query parameter.

### Issue: Auth State Not Persisting

**Solution**:

1. Check localStorage is enabled
2. Verify Zustand persist middleware is working
3. Check for auth store initialization errors

## Future Enhancements

1. **Role-Based Access Control**

   ```typescript
   requireAuth({ roles: ['admin', 'editor'] });
   ```

2. **Permission Checks**

   ```typescript
   requirePermission('projects.edit');
   ```

3. **Session Timeout Warnings**
   - Show warning before session expires
   - Auto-refresh option

4. **Analytics**
   - Track unauthorized access attempts
   - Monitor auth flow metrics

## Related Files

- **Route Guards**: `/src/lib/route-guards.ts`
- **Auth Store**: `/src/stores/authStore.ts`
- **Auth Hooks**: `/src/hooks/useAuth.ts`
- **Tests**: `/src/__tests__/route-guards.test.ts`
- **Documentation**: `/docs/ROUTE_PROTECTION.md`

## Summary

Route protection is now fully implemented across the frontend:

- ✅ 39 protected routes
- ✅ Automatic redirect with return URL
- ✅ Type-safe implementation
- ✅ Comprehensive test coverage
- ✅ Full documentation
- ✅ Backward compatible

All protected routes now properly enforce authentication, preventing unauthorized access while maintaining a smooth user experience with automatic redirect and return URL handling.
