refactor: update PDF view model and routing for improved session management

integration_test/pdf_view_test.dart

@@ -61,17 +61,17 @@ void main() {
     final ctx = tester.element(find.byType(PdfSignatureHomePage));
     final container = ProviderScope.containerOf(ctx);
     final vm = container.read(pdfViewModelProvider);
-    expect(vm, 1);
+    expect(vm.currentPage, 1);
 
     container.read(pdfViewModelProvider.notifier).jumpToPage(2);
     await tester.pumpAndSettle();
     await tester.pump(const Duration(milliseconds: 120));
-    expect(container.read(pdfViewModelProvider), 2);
+    expect(container.read(pdfViewModelProvider).currentPage, 2);
 
     container.read(pdfViewModelProvider.notifier).jumpToPage(3);
     await tester.pumpAndSettle();
     await tester.pump(const Duration(milliseconds: 120));
-    expect(container.read(pdfViewModelProvider), 3);
+    expect(container.read(pdfViewModelProvider).currentPage, 3);
   });
 
   testWidgets('PDF View: zoom in/out', (tester) async {
@@ -166,7 +166,7 @@ void main() {
 
     final ctx = tester.element(find.byType(PdfSignatureHomePage));
     final container = ProviderScope.containerOf(ctx);
-    expect(container.read(pdfViewModelProvider), 1);
+    expect(container.read(pdfViewModelProvider).currentPage, 1);
 
     final pagesSidebar = find.byType(PagesSidebar);
     expect(pagesSidebar, findsOneWidget);
@@ -180,7 +180,7 @@ void main() {
     await tester.tap(page3Thumbnail);
     await tester.pumpAndSettle();
 
-    expect(container.read(pdfViewModelProvider), 3);
+    expect(container.read(pdfViewModelProvider).currentPage, 3);
   });
 
   testWidgets('PDF View: thumbnails scroll and select', (tester) async {
@@ -221,7 +221,7 @@ void main() {
 
     final ctx = tester.element(find.byType(PdfSignatureHomePage));
     final container = ProviderScope.containerOf(ctx);
-    expect(container.read(pdfViewModelProvider), 1);
+    expect(container.read(pdfViewModelProvider).currentPage, 1);
 
     final pagesSidebar = find.byType(PagesSidebar);
     expect(pagesSidebar, findsOneWidget);
@@ -229,13 +229,84 @@ void main() {
     await tester.drag(pagesSidebar, const Offset(0, -200));
     await tester.pumpAndSettle();
 
-    expect(find.text('1'), findsOneWidget);
+    // Page number '1' may appear in multiple text widgets (e.g., overlay/toolbar); restrict to sidebar.
-    expect(container.read(pdfViewModelProvider), 1);
+    final page1InSidebar = find.descendant(
+      of: pagesSidebar,
+      matching: find.text('1'),
+    );
+    expect(page1InSidebar, findsOneWidget);
+    expect(container.read(pdfViewModelProvider).currentPage, 1);
 
     // Select page 2 thumbnail and verify page changes
-    await tester.tap(find.text('2'));
+    final page2InSidebar = find.descendant(
+      of: pagesSidebar,
+      matching: find.text('2'),
+    );
+    await tester.tap(page2InSidebar);
     await tester.pumpAndSettle();
-    expect(container.read(pdfViewModelProvider), 2);
+    expect(container.read(pdfViewModelProvider).currentPage, 2);
+  });
+
+  testWidgets('PDF View: scroll thumbnails to reveal and select last page', (
+    tester,
+  ) async {
+    final pdfBytes =
+        await File('integration_test/data/sample-local-pdf.pdf').readAsBytes();
+    SharedPreferences.setMockInitialValues({});
+    final prefs = await SharedPreferences.getInstance();
+
+    await tester.pumpWidget(
+      ProviderScope(
+        overrides: [
+          preferencesRepositoryProvider.overrideWith(
+            (ref) => PreferencesStateNotifier(prefs),
+          ),
+          documentRepositoryProvider.overrideWith(
+            (ref) =>
+                DocumentStateNotifier()
+                  ..openPicked(pageCount: 3, bytes: pdfBytes),
+          ),
+          pdfViewModelProvider.overrideWith(
+            (ref) => PdfViewModel(ref, useMockViewer: false),
+          ),
+        ],
+        child: MaterialApp(
+          localizationsDelegates: AppLocalizations.localizationsDelegates,
+          supportedLocales: AppLocalizations.supportedLocales,
+          locale: const Locale('en'),
+          home: PdfSignatureHomePage(
+            onPickPdf: () async {},
+            onClosePdf: () {},
+            currentFile: fs.XFile('test.pdf'),
+          ),
+        ),
+      ),
+    );
+
+    await tester.pumpAndSettle();
+
+    final ctx = tester.element(find.byType(PdfSignatureHomePage));
+    final container = ProviderScope.containerOf(ctx);
+    expect(container.read(pdfViewModelProvider).currentPage, 1);
+
+    final pagesSidebar = find.byType(PagesSidebar);
+    expect(pagesSidebar, findsOneWidget);
+
+    // Ensure page 3 not initially in view by trying to find it and allowing that it might be offstage.
+    // Perform a scroll/drag to bring page 3 into view.
+    await tester.drag(pagesSidebar, const Offset(0, -400));
+    await tester.pumpAndSettle();
+
+    final page3 = find.descendant(of: pagesSidebar, matching: find.text('3'));
+    expect(page3, findsOneWidget);
+    await tester.tap(page3);
+    await tester.pumpAndSettle();
+    expect(container.read(pdfViewModelProvider).currentPage, 3);
+
+    // Scroll back upward and verify selection persists.
+    await tester.drag(pagesSidebar, const Offset(0, 300));
+    await tester.pumpAndSettle();
+    expect(container.read(pdfViewModelProvider).currentPage, 3);
   });
 
   //TODO: Scroll Thumbs

lib/domain/models/graphic_adjust.dart

@@ -5,7 +5,7 @@ class GraphicAdjust {
 
   const GraphicAdjust({
     this.contrast = 1.0,
-    this.brightness = 0.0,
+    this.brightness = 1.0,
     this.bgRemoval = false,
   });
 

lib/routing/router.dart

@@ -5,126 +5,50 @@ import 'package:go_router/go_router.dart';
 import 'package:pdf_signature/ui/features/pdf/widgets/pdf_screen.dart';
 import 'package:pdf_signature/ui/features/welcome/widgets/welcome_screen.dart';
 import 'package:pdf_signature/data/repositories/document_repository.dart';
-import 'package:pdf_signature/data/repositories/signature_card_repository.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/pdf_view_model.dart';
-import 'package:file_selector/file_selector.dart' as fs;
-import 'package:pdfrx/pdfrx.dart';
 
-class PdfManager {
+// PdfManager removed: responsibilities moved into PdfSessionViewModel.
-  final DocumentStateNotifier _documentNotifier;
-  final SignatureCardStateNotifier _signatureCardNotifier;
-  final GoRouter _router;
-
-  fs.XFile _currentFile = fs.XFile('');
-
-  PdfManager({
-    required DocumentStateNotifier documentNotifier,
-    required SignatureCardStateNotifier signatureCardNotifier,
-    required GoRouter router,
-  }) : _documentNotifier = documentNotifier,
-       _signatureCardNotifier = signatureCardNotifier,
-       _router = router;
-
-  fs.XFile get currentFile => _currentFile;
-
-  Future<void> openPdf({String? path, Uint8List? bytes}) async {
-    int pageCount = 1; // default
-    if (bytes != null) {
-      try {
-        final doc = await PdfDocument.openData(bytes);
-        pageCount = doc.pages.length;
-      } catch (_) {
-        // ignore
-      }
-    }
-
-    // Update file reference if path is provided
-    if (path != null) {
-      _currentFile = fs.XFile(path);
-    }
-
-    _documentNotifier.openPicked(pageCount: pageCount, bytes: bytes);
-    _signatureCardNotifier.clearAll();
-
-    // Navigate to PDF screen after successfully opening PDF
-    _router.go('/pdf');
-  }
-
-  void closePdf() {
-    _documentNotifier.close();
-    _signatureCardNotifier.clearAll();
-    _currentFile = fs.XFile('');
-
-    // Navigate back to welcome screen when closing PDF
-    _router.go('/');
-  }
-
-  Future<void> pickAndOpenPdf() async {
-    final typeGroup = const fs.XTypeGroup(label: 'PDF', extensions: ['pdf']);
-    final file = await fs.openFile(acceptedTypeGroups: [typeGroup]);
-    if (file != null) {
-      Uint8List? bytes;
-      try {
-        bytes = await file.readAsBytes();
-      } catch (_) {
-        bytes = null;
-      }
-      await openPdf(path: file.path, bytes: bytes);
-    }
-  }
-}
 
 final routerProvider = Provider<GoRouter>((ref) {
-  // Create PdfManager instance with dependencies
+  // Determine initial location based on current document state.
-  final documentNotifier = ref.read(documentRepositoryProvider.notifier);
+  // Access the state via the provider (not via the notifier's protected .state).
-  final signatureCardNotifier = ref.read(
+  final docState = ref.read(documentRepositoryProvider);
-    signatureCardRepositoryProvider.notifier,
+  final initialLocation = docState.loaded ? '/pdf' : '/';
-  );
+  // Session view model will be obtained inside each route builder; no shared
+  // late variable (avoids LateInitializationError on rebuilds).
 
-  // Create a navigator key for the router
   final navigatorKey = GlobalKey<NavigatorState>();
-
+  late final GoRouter router; // declare before use in builders
-  // Create a late variable for the router
-  late final GoRouter router;
-
-  // Create PdfManager with router dependency (will be set after router creation)
-  late final PdfManager pdfManager;
-
-  // If tests pre-load a document, start at /pdf so sidebars and controls
-  // are present immediately.
-  final initialLocation = documentNotifier.debugState.loaded ? '/pdf' : '/';
 
   router = GoRouter(
     navigatorKey: navigatorKey,
     routes: [
       GoRoute(
         path: '/',
-        builder:
+        builder: (context, state) {
-            (context, state) => WelcomeScreen(
+          final sessionVm = ref.read(pdfSessionViewModelProvider(router));
-              onPickPdf: () => pdfManager.pickAndOpenPdf(),
+          return WelcomeScreen(
-              onOpenPdf:
+            onPickPdf: () => sessionVm.pickAndOpenPdf(),
-                  ({String? path, Uint8List? bytes, String? fileName}) =>
+            onOpenPdf:
-                      pdfManager.openPdf(path: path, bytes: bytes),
+                ({String? path, Uint8List? bytes, String? fileName}) =>
-            ),
+                    sessionVm.openPdf(path: path, bytes: bytes),
+          );
+        },
       ),
       GoRoute(
         path: '/pdf',
-        builder:
+        builder: (context, state) {
-            (context, state) => PdfSignatureHomePage(
+          final sessionVm = ref.read(pdfSessionViewModelProvider(router));
-              onPickPdf: () => pdfManager.pickAndOpenPdf(),
+          return PdfSignatureHomePage(
-              onClosePdf: () => pdfManager.closePdf(),
+            onPickPdf: () => sessionVm.pickAndOpenPdf(),
-              currentFile: pdfManager.currentFile,
+            onClosePdf: () => sessionVm.closePdf(),
-            ),
+            currentFile: sessionVm.currentFile,
+          );
+        },
       ),
     ],
     initialLocation: initialLocation,
   );
 
-  // Now create PdfManager with the router
-  pdfManager = PdfManager(
-    documentNotifier: documentNotifier,
-    signatureCardNotifier: signatureCardNotifier,
-    router: router,
-  );
-
   return router;
 });

lib/ui/features/pdf/view_model/pdf_view_model.dart

@@ -5,6 +5,8 @@ import 'package:pdf_signature/data/repositories/document_repository.dart';
 import 'package:pdf_signature/data/repositories/signature_card_repository.dart';
 import 'package:pdf_signature/domain/models/model.dart';
 import 'package:pdfrx/pdfrx.dart';
+import 'package:file_selector/file_selector.dart' as fs;
+import 'package:go_router/go_router.dart';
 
 class PdfViewModel extends ChangeNotifier {
   final Ref ref;
@@ -62,28 +64,8 @@ class PdfViewModel extends ChangeNotifier {
     notifyListeners();
   }
 
-  Future<void> openPdf({required String path, Uint8List? bytes}) async {
-    int pageCount = 1;
-    if (bytes != null) {
-      try {
-        final doc = await PdfDocument.openData(bytes);
-        pageCount = doc.pages.length;
-      } catch (_) {
-        // ignore
-      }
-    }
-    ref
-        .read(documentRepositoryProvider.notifier)
-        .openPicked(pageCount: pageCount, bytes: bytes);
-    clearAllSignatureCards();
-
-    currentPage = 1; // Reset current page to 1
-  }
-
   // Document repository methods
-  void closeDocument() {
+  // Lifecycle (open/close) removed: handled exclusively by PdfSessionViewModel.
-    ref.read(documentRepositoryProvider.notifier).close();
-  }
 
   void setPageCount(int count) {
     ref.read(documentRepositoryProvider.notifier).setPageCount(count);
@@ -197,3 +179,63 @@ class PdfViewModel extends ChangeNotifier {
 final pdfViewModelProvider = ChangeNotifierProvider<PdfViewModel>((ref) {
   return PdfViewModel(ref);
 });
+
+/// ViewModel managing PDF session lifecycle (file picking/open/close) and
+/// navigation. Replaces the previous PdfManager helper.
+class PdfSessionViewModel extends ChangeNotifier {
+  final Ref ref;
+  final GoRouter router;
+  fs.XFile _currentFile = fs.XFile('');
+
+  PdfSessionViewModel({required this.ref, required this.router});
+
+  fs.XFile get currentFile => _currentFile;
+
+  Future<void> pickAndOpenPdf() async {
+    final typeGroup = const fs.XTypeGroup(label: 'PDF', extensions: ['pdf']);
+    final file = await fs.openFile(acceptedTypeGroups: [typeGroup]);
+    if (file != null) {
+      Uint8List? bytes;
+      try {
+        bytes = await file.readAsBytes();
+      } catch (_) {
+        bytes = null;
+      }
+      await openPdf(path: file.path, bytes: bytes);
+    }
+  }
+
+  Future<void> openPdf({String? path, Uint8List? bytes}) async {
+    int pageCount = 1; // default
+    if (bytes != null) {
+      try {
+        final doc = await PdfDocument.openData(bytes);
+        pageCount = doc.pages.length;
+      } catch (_) {
+        // ignore invalid bytes
+      }
+    }
+    if (path != null) {
+      _currentFile = fs.XFile(path);
+    }
+    ref
+        .read(documentRepositoryProvider.notifier)
+        .openPicked(pageCount: pageCount, bytes: bytes);
+    ref.read(signatureCardRepositoryProvider.notifier).clearAll();
+    router.go('/pdf');
+    notifyListeners();
+  }
+
+  void closePdf() {
+    ref.read(documentRepositoryProvider.notifier).close();
+    ref.read(signatureCardRepositoryProvider.notifier).clearAll();
+    _currentFile = fs.XFile('');
+    router.go('/');
+    notifyListeners();
+  }
+}
+
+final pdfSessionViewModelProvider =
+    ChangeNotifierProvider.family<PdfSessionViewModel, GoRouter>((ref, router) {
+      return PdfSessionViewModel(ref: ref, router: router);
+    });

lib/ui/features/welcome/view_model/welcome_view_model.dart

@@ -1,19 +1,23 @@
 import 'dart:typed_data';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:pdf_signature/ui/features/pdf/view_model/pdf_view_model.dart';
+import 'package:go_router/go_router.dart';
+import 'package:pdf_signature/routing/router.dart';
 
 class WelcomeViewModel {
   final Ref ref;
+  final GoRouter router;
 
-  WelcomeViewModel(this.ref);
+  WelcomeViewModel(this.ref, this.router);
 
   Future<void> openPdf({required String path, Uint8List? bytes}) async {
-    await ref
+    // Use PdfSessionViewModel to open and navigate.
-        .read(pdfViewModelProvider.notifier)
+    final session = ref.read(pdfSessionViewModelProvider(router));
-        .openPdf(path: path, bytes: bytes);
+    await session.openPdf(path: path, bytes: bytes);
   }
 }
 
 final welcomeViewModelProvider = Provider<WelcomeViewModel>((ref) {
-  return WelcomeViewModel(ref);
+  final router = ref.read(routerProvider);
+  return WelcomeViewModel(ref, router);
 });