feat(app): show added material in its studyset tab

An Anki import switches to Flashcards when the cards come into this
studyset (flattened or tagged by subdeck), not when subdecks become
sub-studysets; an imported path switches to Paths. Creating flashcards,
a note or a path switches to its tab as well, seen on coming back.

On opening, the studyset shows the first tab with content of its own:
unfinished paths, then flashcards, then notes; Flashcards when it holds
nothing. Its topics' content doesn't count, since the tabs list only the
studyset's own. A tab tapped or swiped to by the person, or material
added, stays.

Add material is built both in the app bar and in the bottom bar, so a
ContentTabCubit carries the requests to the tab controller, and
importFromAnki now returns the mode it imported with.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/lib/src/feature/anki/widget/anki_import_sheet.dart

@@ -11,8 +11,9 @@ import 'package:material_ui/material_ui.dart';
 
 /// Lets the person pick an Anki package (`.apkg`, or a whole collection's
 /// `.colpkg`) and imports it into the studyset [studysetId], as they choose
-/// in a sheet; then says what came over.
-Future<void> importFromAnki(
+/// in a sheet; then says what came over. Completes with how its decks became
+/// studysets, or with null when nothing was imported.
+Future<AnkiImportMode?> importFromAnki(
   BuildContext context, {
   required String studysetId,
 }) async {
@@ -23,7 +24,7 @@ Future<void> importFromAnki(
     extensions: const ['apkg', 'colpkg'],
   );
   if (file == null || !context.mounted) {
-    return;
+    return null;
   }
   final done = await showAdaptiveSheet<AnkiImportStateDone>(
     context,
@@ -49,7 +50,7 @@ Future<void> importFromAnki(
     },
   );
   if (done == null) {
-    return;
+    return null;
   }
   final result = done.result;
   messenger.showSnackBar(
@@ -71,6 +72,7 @@ Future<void> importFromAnki(
       ),
     ),
   );
+  return done.mode;
 }
 
 class const _AnkiImport() extends StatelessWidget {

halkyon_learn_flutter/lib/src/feature/studyset/bloc/content_tab_cubit.dart

@@ -0,0 +1,28 @@
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+/// The tabs of a studyset's content, in their order.
+enum StudysetTab() {
+  /// Its learning paths.
+  paths,
+
+  /// Its flashcards.
+  flashcards,
+
+  /// Its notes.
+  notes,
+}
+
+/// The last request to show a content tab, if any; `serial` tells two
+/// requests for one tab apart.
+typedef ContentTabState = ({StudysetTab tab, int serial})?;
+
+/// Asks the studyset screen to show a content tab: the one where material
+/// just added or imported lands (decided 2026-10-03), so the person sees it
+/// rather than looking for it.
+class ContentTabCubit() extends Cubit<ContentTabState> {
+  this : super(null);
+
+  /// Shows [tab].
+  void show(StudysetTab tab) =>
+      emit((tab: tab, serial: (state?.serial ?? 0) + 1));
+}

halkyon_learn_flutter/lib/src/feature/studyset/widget/studyset_screen.dart

@@ -1,4 +1,6 @@
+import 'dart:async';
 import 'dart:convert';
+import 'dart:developer';
 import 'dart:math' as math;
 
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -15,12 +17,14 @@ import 'package:halkyon_learn_flutter/src/core/widget/scroll_hiding_fab.dart';
 import 'package:halkyon_learn_flutter/src/core/widget/section_card.dart';
 import 'package:halkyon_learn_flutter/src/core/widget/title_with_kicker.dart';
 import 'package:halkyon_learn_flutter/src/core/widget/undo_snack_bar.dart';
+import 'package:halkyon_learn_flutter/src/feature/anki/data/anki_importer.dart';
 import 'package:halkyon_learn_flutter/src/feature/anki/widget/anki_import_sheet.dart';
 import 'package:halkyon_learn_flutter/src/feature/card/widget/card_list.dart';
 import 'package:halkyon_learn_flutter/src/feature/learning_path/bloc/path_list_bloc.dart';
 import 'package:halkyon_learn_flutter/src/feature/learning_path/widget/path_list.dart';
 import 'package:halkyon_learn_flutter/src/feature/note/widget/note_list.dart';
 import 'package:halkyon_learn_flutter/src/feature/study/model/study_progress.dart';
+import 'package:halkyon_learn_flutter/src/feature/studyset/bloc/content_tab_cubit.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/bloc/studyset_list_bloc.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/model/studyset.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/model/studyset_tree.dart';
@@ -76,6 +80,8 @@ class const StudysetScreen({
             studyset.id,
           )..add(const PathListEventStarted()),
         ),
+        // The content tab to show once material was added.
+        BlocProvider(create: (context) => ContentTabCubit()),
       ],
       child: MultiBlocListener(
         listeners: [
@@ -95,6 +101,9 @@ class const StudysetScreen({
             listener: (context, state) {
               final l10n = AppLocalizations.of(context);
               final result = state.importResult!;
+              if (result.failure == null) {
+                context.read<ContentTabCubit>().show(StudysetTab.paths);
+              }
               final message = switch (result.failure) {
                 final failure? => l10n.pathImportFailed(failure),
                 null => [
@@ -259,9 +268,14 @@ class const _StudysetView({
 }
 
 /// The studyset's content, in tabs that appear as their features land:
-/// learning paths, flashcards and notes for now. It opens on the flashcards,
-/// and on the paths instead once it is known that some path isn't completed
-/// yet, unless the person chose a tab meanwhile.
+/// learning paths, flashcards and notes for now.
+///
+/// It opens on the first tab with something of the studyset's own in it
+/// (its topics' content is in theirs), in their order: paths not completed
+/// yet, flashcards, notes; on the flashcards when there is nothing (decided
+/// 2026-10-03). Material added or imported shows in its own tab
+/// ([ContentTabCubit]). Once the person chose a tab, or material was added,
+/// opening no longer moves it.
 class const _Content({required final String studysetId})
     extends StatefulWidget {
   @override
@@ -271,13 +285,26 @@ class const _Content({required final String studysetId})
 class _ContentState()
     extends State<_Content>
     with SingleTickerProviderStateMixin {
-  late final _tabs = TabController(length: 3, vsync: this, initialIndex: 1);
+  late final _tabs = TabController(
+    length: StudysetTab.values.length,
+    vsync: this,
+    initialIndex: StudysetTab.flashcards.index,
+  );
+
+  /// Whether the tab shown is settled: chosen on opening, by the person, or
+  /// for material added.
   var _settled = false;
 
+  /// Whether the studyset itself holds cards and notes, read once on
+  /// opening; null until then.
+  ({bool cards, bool notes})? _holds;
+
   @override
   void initState() {
     super.initState();
+    // Swiping to a tab is choosing it as much as tapping it is.
     _tabs.addListener(() => _settled = true);
+    unawaited(_readWhatItHolds());
   }
 
   @override
@@ -286,18 +313,67 @@ class _ContentState()
     super.dispose();
   }
 
+  Future<void> _readWhatItHolds() async {
+    final person = PersonScope.of(context);
+    try {
+      final cards = await person.cards.cardsOf(widget.studysetId);
+      final notes = await person.notes.countsByStudyset();
+      _holds = (
+        cards: cards.isNotEmpty,
+        notes: notes.containsKey(widget.studysetId),
+      );
+    } on Object catch (error) {
+      // It stays on the flashcards, as it opened.
+      log(
+        'Reading what a studyset holds failed',
+        name: 'Studyset',
+        error: error,
+      );
+      return;
+    }
+    _chooseOnOpening();
+  }
+
+  void _show(StudysetTab tab) {
+    _settled = true;
+    if (_tabs.index != tab.index) {
+      _tabs.animateTo(tab.index);
+    }
+  }
+
+  /// Chooses the tab to open on, once enough is known: paths in progress
+  /// win at once; the others once both are known.
+  void _chooseOnOpening() {
+    if (_settled || !mounted) {
+      return;
+    }
+    final paths = context.read<PathListBloc>().state;
+    if (paths.completionKnown && paths.hasOpenPaths) {
+      _show(StudysetTab.paths);
+    } else if (paths.completionKnown && _holds != null) {
+      _show(switch (_holds!) {
+        (cards: false, notes: true) => StudysetTab.notes,
+        _ => StudysetTab.flashcards,
+      });
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     final l10n = AppLocalizations.of(context);
-    return BlocListener<PathListBloc, PathListState>(
-      listenWhen: (before, now) =>
-          !before.completionKnown && now.completionKnown,
-      listener: (context, state) {
-        if (!_settled && state.hasOpenPaths) {
-          _tabs.index = 0;
-        }
-        _settled = true;
-      },
+    return MultiBlocListener(
+      listeners: [
+        BlocListener<ContentTabCubit, ContentTabState>(
+          listener: (context, request) {
+            if (request != null) {
+              _show(request.tab);
+            }
+          },
+        ),
+        BlocListener<PathListBloc, PathListState>(
+          listener: (context, _) => _chooseOnOpening(),
+        ),
+      ],
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.stretch,
         children: [
@@ -306,9 +382,14 @@ class _ContentState()
             isScrollable: true,
             tabAlignment: TabAlignment.start,
             tabs: [
-              Tab(text: l10n.studysetTabPaths),
-              Tab(text: l10n.studysetTabFlashcards),
-              Tab(text: l10n.studysetTabNotes),
+              for (final tab in StudysetTab.values)
+                Tab(
+                  text: switch (tab) {
+                    StudysetTab.paths => l10n.studysetTabPaths,
+                    StudysetTab.flashcards => l10n.studysetTabFlashcards,
+                    StudysetTab.notes => l10n.studysetTabNotes,
+                  },
+                ),
             ],
           ),
           Expanded(
@@ -454,7 +535,9 @@ class const _StudyPill({
 
 /// What can be added to the studyset, behind [builder]'s trigger:
 /// flashcards, notes and learning paths for now; files come with their
-/// feature.
+/// feature. What is added shows in its own tab ([ContentTabCubit]): what is
+/// written there once the person comes back, what is imported once it is
+/// in.
 class const _AddMaterial({
   required final String studysetId,
   required final Widget Function(BuildContext context, MenuController menu)
@@ -467,19 +550,27 @@ class const _AddMaterial({
       menuChildren: [
         MenuItemButton(
           leadingIcon: const Icon(LucideIcons.plus),
-          onPressed: () => context.push(RoutePaths.newCard(studysetId)),
+          onPressed: () {
+            context.read<ContentTabCubit>().show(StudysetTab.flashcards);
+            context.push(RoutePaths.newCard(studysetId));
+          },
           child: Text(l10n.studysetCreateFlashcards),
         ),
         MenuItemButton(
           leadingIcon: const Icon(LucideIcons.notebookPen),
-          onPressed: () => context.push(RoutePaths.newNote(studysetId)),
+          onPressed: () {
+            context.read<ContentTabCubit>().show(StudysetTab.notes);
+            context.push(RoutePaths.newNote(studysetId));
+          },
           child: Text(l10n.studysetCreateNote),
         ),
         MenuItemButton(
           leadingIcon: const Icon(LucideIcons.route),
           onPressed: () async {
             final bloc = context.read<PathListBloc>();
+            final tabs = context.read<ContentTabCubit>();
             if (await askForNewPath(context) case final content?) {
+              tabs.show(StudysetTab.paths);
               bloc.add(PathListEventCreateRequested(content));
             }
           },
@@ -487,7 +578,17 @@ class const _AddMaterial({
         ),
         MenuItemButton(
           leadingIcon: const Icon(LucideIcons.fileInput),
-          onPressed: () => importFromAnki(context, studysetId: studysetId),
+          onPressed: () async {
+            final tabs = context.read<ContentTabCubit>();
+            // Cards that came into this studyset show in its flashcards;
+            // subdecks become topics instead.
+            switch (await importFromAnki(context, studysetId: studysetId)) {
+              case AnkiImportMode.flatten || AnkiImportMode.tagBySubdeck:
+                tabs.show(StudysetTab.flashcards);
+              case AnkiImportMode.subStudysets || null:
+                break;
+            }
+          },
           child: Text(l10n.ankiImportMenu),
         ),
         MenuItemButton(

halkyon_learn_flutter/test/feature/anki/widget/anki_import_sheet_test.dart

@@ -1,8 +1,11 @@
 import 'dart:typed_data';
 
 import 'package:flutter_test/flutter_test.dart';
+import 'package:halkyon_learn_flutter/src/core/content/rich_content.dart';
 import 'package:halkyon_learn_flutter/src/core/router/route_paths.dart';
 import 'package:halkyon_learn_flutter/src/feature/card/data/card_repository.dart';
+import 'package:halkyon_learn_flutter/src/feature/note/data/note_repository.dart';
+import 'package:halkyon_learn_flutter/src/feature/note/model/note_content.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/data/studyset_payload.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/model/studyset_content.dart';
 import 'package:material_ui/material_ui.dart';
@@ -10,6 +13,7 @@ import 'package:material_ui/material_ui.dart';
 import '../../../support/fake_asset_server_gateway.dart';
 import '../../../support/fake_card_gateway.dart';
 import '../../../support/fake_file_picker.dart';
+import '../../../support/fake_note_gateway.dart';
 import '../../../support/fake_studyset_gateway.dart';
 import '../../../support/pump_app.dart';
 import '../../../support/test_dependencies.dart';
@@ -19,13 +23,30 @@ void main() {
   late FakeCardGateway cardGateway;
   late FakeFilePicker files;
   late FakeAssetServerGateway server;
+  late FakeNoteGateway noteGateway;
 
   setUp(() {
     cardGateway = FakeCardGateway();
     files = FakeFilePicker();
     server = FakeAssetServerGateway();
+    noteGateway = FakeNoteGateway();
   });
 
+  /// The index of the studyset's content tab shown: 0 paths, 1 flashcards,
+  /// 2 notes.
+  int shownTab(WidgetTester tester) =>
+      tester.widget<TabBar>(find.byType(TabBar)).controller!.index;
+
+  /// A note in the studyset, so that it opens on its notes.
+  Future<void> withNote() async {
+    final notes = NoteRepository(noteGateway);
+    addTearDown(notes.dispose);
+    await notes.create(
+      'japanese',
+      NoteContent(title: 'Particles', body: RichContent.empty()),
+    );
+  }
+
   /// Opens the studyset Japanese, in a window wide enough for Add material
   /// to be a button.
   Future<void> showStudyset(WidgetTester tester) async {
@@ -41,11 +62,15 @@ void main() {
             encodeStudysetPayload(StudysetContent.titled('Japanese')),
           ),
         cardGateway: cardGateway,
+        noteGateway: noteGateway,
         files: files,
         assetServer: server,
       ),
       location: RoutePaths.studyset('japanese'),
     );
+    // Lets the lists settle, and the screen choose its first tab.
+    await tester.pump(const Duration(seconds: 1));
+    await tester.pumpAndSettle();
   }
 
   /// Chooses Import from Anki under Add material.
@@ -90,6 +115,33 @@ void main() {
     expect(await cards.cardsOf('japanese'), hasLength(4));
   });
 
+  testWidgets('shows the flashcards after a deck came into this studyset, '
+      'whatever tab was open', (tester) async {
+    await withNote();
+    await startImport(tester, fixture('anki_latest.apkg'));
+    await tester.tap(find.text('Tag cards by subdeck'));
+    await tester.pump();
+    await tester.tap(find.widgetWithText(FilledButton, 'Import'));
+    await tester.pumpAndSettle();
+
+    expect(shownTab(tester), 1);
+  });
+
+  testWidgets('leaves the tab as it was when the subdecks became '
+      'sub-studysets', (tester) async {
+    await withNote();
+    files.next = (name: 'japanese.apkg', bytes: fixture('anki_latest.apkg'));
+    await showStudyset(tester);
+    expect(shownTab(tester), 2);
+    await chooseImport(tester);
+    await tester.tap(find.text('Recreate as sub-studysets'));
+    await tester.pump();
+    await tester.tap(find.widgetWithText(FilledButton, 'Import'));
+    await tester.pumpAndSettle();
+
+    expect(shownTab(tester), 2);
+  });
+
   testWidgets('warns when the files may not fit in the room left', (
     tester,
   ) async {

halkyon_learn_flutter/test/feature/learning_path/widget/path_screens_test.dart

@@ -7,12 +7,15 @@ import 'package:halkyon_learn_flutter/src/feature/learning_path/data/learning_pa
 import 'package:halkyon_learn_flutter/src/feature/learning_path/model/exercise.dart';
 import 'package:halkyon_learn_flutter/src/feature/learning_path/model/learning_path.dart';
 import 'package:halkyon_learn_flutter/src/feature/learning_path/model/step_content.dart';
+import 'package:halkyon_learn_flutter/src/feature/note/data/note_repository.dart';
+import 'package:halkyon_learn_flutter/src/feature/note/model/note_content.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/data/studyset_payload.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/model/studyset_content.dart';
 import 'package:material_ui/material_ui.dart';
 
 import '../../../support/fake_file_picker.dart';
 import '../../../support/fake_learning_path_gateway.dart';
+import '../../../support/fake_note_gateway.dart';
 import '../../../support/fake_path_answer_gateway.dart';
 import '../../../support/fake_studyset_gateway.dart';
 import '../../../support/pump_app.dart';
@@ -23,6 +26,7 @@ void main() {
   late FakeLearningPathGateway pathGateway;
   late FakePathAnswerGateway answers;
   late FakeFilePicker files;
+  late FakeNoteGateway noteGateway;
 
   setUp(() {
     studysets = FakeStudysetGateway()
@@ -33,8 +37,14 @@ void main() {
     pathGateway = FakeLearningPathGateway();
     answers = FakePathAnswerGateway();
     files = FakeFilePicker();
+    noteGateway = FakeNoteGateway();
   });
 
+  /// The index of the studyset's content tab shown: 0 paths, 1 flashcards,
+  /// 2 notes.
+  int shownTab(WidgetTester tester) =>
+      tester.widget<TabBar>(find.byType(TabBar)).controller!.index;
+
   Future<void> showApp(WidgetTester tester, String location) async {
     tester.view.physicalSize = const Size(1200, 1000);
     tester.view.devicePixelRatio = 1;
@@ -45,6 +55,7 @@ void main() {
         studysetGateway: studysets,
         pathGateway: pathGateway,
         answerGateway: answers,
+        noteGateway: noteGateway,
         files: files,
       ),
       location: location,
@@ -92,6 +103,39 @@ void main() {
     expect(find.text('Particles'), findsOneWidget);
   });
 
+  testWidgets('a studyset with only notes opens on them', (tester) async {
+    final notes = NoteRepository(noteGateway);
+    addTearDown(notes.dispose);
+    await notes.create(
+      'japanese',
+      NoteContent(title: 'Particles', body: RichContent.empty()),
+    );
+
+    await showApp(tester, RoutePaths.studyset('japanese'));
+
+    expect(shownTab(tester), 2);
+    expect(find.text('Particles'), findsOneWidget);
+  });
+
+  testWidgets("notes only in its topics don't open the studyset on its own "
+      'empty notes', (tester) async {
+    studysets.receiveRemoteChange(
+      'grammar',
+      encodeStudysetPayload(StudysetContent.titled('Grammar')),
+      parentId: 'japanese',
+    );
+    final notes = NoteRepository(noteGateway);
+    addTearDown(notes.dispose);
+    await notes.create(
+      'grammar',
+      NoteContent(title: 'Particles', body: RichContent.empty()),
+    );
+
+    await showApp(tester, RoutePaths.studyset('japanese'));
+
+    expect(shownTab(tester), 1);
+  });
+
   testWidgets('without paths, the studyset opens on its flashcards', (
     tester,
   ) async {
@@ -156,11 +200,34 @@ void main() {
       findsOneWidget,
     );
     expect(find.textContaining('1 block was left out'), findsOneWidget);
-    await tester.tap(find.text('Paths'));
-    await tester.pumpAndSettle();
+    // The paths show by themselves.
+    expect(shownTab(tester), 0);
     expect(find.text('Particles'), findsOneWidget);
   });
 
+  testWidgets('a note written from Add material shows in the Notes tab on '
+      'coming back, as flashcards do in theirs', (tester) async {
+    final paths = repository();
+    final id = await paths.createPath(
+      'japanese',
+      LearningPathContent.titled('Particles'),
+    );
+    await paths.createStep(id, StepKind.info, step(StepKind.info, 'Read'));
+    await showApp(tester, RoutePaths.studyset('japanese'));
+    expect(shownTab(tester), 0);
+
+    await tester.tap(find.text('Add material'));
+    await tester.pumpAndSettle();
+    await chooseInMenu(tester, 'Create a note');
+    await tester.enterText(find.byType(TextField), 'Topic or subject');
+    await tester.pump();
+    await tester.pageBack();
+    await tester.pumpAndSettle();
+
+    expect(shownTab(tester), 2);
+    expect(find.text('Topic or subject'), findsOneWidget);
+  });
+
   testWidgets('works through a path: an info step, a choice answered wrong '
       'then right, and the finish', (tester) async {
     final paths = repository();