feat(app): reset a studyset's progress, with an undo

The studyset's options offer Reset progress: after asking, every card
in it and in the studysets inside it starts afresh as new (a 'reset'
entry each), its history kept; an undo for a few seconds deletes those
entries again.

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/l10n/app_en.arb

@@ -303,6 +303,12 @@
   "studyFewer": "Fewer",
   "studyMore": "More",
 
+  "studysetMenuReset": "Reset progress",
+  "studysetResetTitle": "Reset progress?",
+  "studysetResetMessage": "Every flashcard in it, and in the studysets inside it, starts afresh as new, on all your devices. Your study history stays. You can undo this for a few seconds.",
+  "studysetResetConfirm": "Reset",
+  "studysetResetDone": "Progress reset",
+
   "commonCancel": "Cancel",
   "commonClose": "Close",
   "commonUndo": "Undo",

halkyon_learn_flutter/lib/l10n/app_localizations.dart

@@ -1660,6 +1660,36 @@ abstract class AppLocalizations {
   /// **'More'**
   String get studyMore;
 
+  /// No description provided for @studysetMenuReset.
+  ///
+  /// In en, this message translates to:
+  /// **'Reset progress'**
+  String get studysetMenuReset;
+
+  /// No description provided for @studysetResetTitle.
+  ///
+  /// In en, this message translates to:
+  /// **'Reset progress?'**
+  String get studysetResetTitle;
+
+  /// No description provided for @studysetResetMessage.
+  ///
+  /// In en, this message translates to:
+  /// **'Every flashcard in it, and in the studysets inside it, starts afresh as new, on all your devices. Your study history stays. You can undo this for a few seconds.'**
+  String get studysetResetMessage;
+
+  /// No description provided for @studysetResetConfirm.
+  ///
+  /// In en, this message translates to:
+  /// **'Reset'**
+  String get studysetResetConfirm;
+
+  /// No description provided for @studysetResetDone.
+  ///
+  /// In en, this message translates to:
+  /// **'Progress reset'**
+  String get studysetResetDone;
+
   /// No description provided for @commonCancel.
   ///
   /// In en, this message translates to:

halkyon_learn_flutter/lib/l10n/app_localizations_en.dart

@@ -942,6 +942,22 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get studyMore => 'More';
 
+  @override
+  String get studysetMenuReset => 'Reset progress';
+
+  @override
+  String get studysetResetTitle => 'Reset progress?';
+
+  @override
+  String get studysetResetMessage =>
+      'Every flashcard in it, and in the studysets inside it, starts afresh as new, on all your devices. Your study history stays. You can undo this for a few seconds.';
+
+  @override
+  String get studysetResetConfirm => 'Reset';
+
+  @override
+  String get studysetResetDone => 'Progress reset';
+
   @override
   String get commonCancel => 'Cancel';
 

halkyon_learn_flutter/lib/src/feature/study/data/review_gateway.dart

@@ -17,6 +17,10 @@ abstract interface class ReviewGateway() {
   /// Appends reviews; reviews are never changed.
   Future<void> insert(Iterable<ReviewRow> reviews);
 
+  /// Deletes the fresh starts of the cards [cardIds] made at [at], to undo
+  /// them.
+  Future<void> deleteResets(Set<String> cardIds, DateTime at);
+
   /// Fires when a sync brought changes from the person's other devices.
   Stream<void> get remoteChanges;
 }

halkyon_learn_flutter/lib/src/feature/study/data/review_repository.dart

@@ -64,6 +64,10 @@ class ReviewRepository(final ReviewGateway _gateway) {
       ),
   ]);
 
+  /// Undoes [reset] of [cardIds] at [at].
+  Future<void> undoReset(Iterable<String> cardIds, DateTime at) =>
+      _gateway.deleteResets({...cardIds}, at.toUtc());
+
   /// Of [reviews], those of [mode] after the last fresh start.
   List<Review> _since(List<Review> reviews, StudyMode mode) {
     DateTime? start;

halkyon_learn_flutter/lib/src/feature/study/data/sync_review_gateway.dart

@@ -52,6 +52,23 @@ class SyncReviewGateway(
     _sync.requestSync();
   }
 
+  @override
+  Future<void> deleteResets(Set<String> cardIds, DateTime at) async {
+    if (cardIds.isEmpty) {
+      return;
+    }
+    await protocol.ReviewLog.db.deleteWhere(
+      _db,
+      where: (t) =>
+          t.cardId.inSet({
+            for (final id in cardIds) protocol.UuidValue.withValidation(id),
+          }) &
+          t.mode.equals('reset') &
+          t.reviewedAt.equals(at),
+    );
+    _sync.requestSync();
+  }
+
   @override
   Stream<void> get remoteChanges => _sync.merges;
 }

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

@@ -96,6 +96,19 @@ final class const StudysetListEventUnarchiveRequested(
   List<Object?> get props => [id];
 }
 
+/// Start the progress of every card in the studyset [id], and in what is
+/// inside it, afresh.
+final class const StudysetListEventResetRequested(
+  /// The studyset's id.
+  final String id,
+) extends StudysetListEvent {
+  @override
+  List<Object?> get props => [id];
+}
+
+/// Undo the last fresh start.
+final class const StudysetListEventResetUndone() extends StudysetListEvent;
+
 /// Work out the studysets' progress again, as after a study session.
 final class const StudysetListEventProgressRefreshRequested()
     extends StudysetListEvent;
@@ -175,8 +188,32 @@ class StudysetListBloc(
       (event, emit) => _studysets.unarchive(event.id),
     );
     on<StudysetListEventProgressRefreshRequested>(_onProgressRefreshRequested);
+    on<StudysetListEventResetRequested>((event, emit) async {
+      final at = clock.now().toUtc();
+      final cardIds = [
+        for (final id in subtreeOf(event.id, _studysetsRead))
+          for (final card in await _cards.cardsOf(id)) card.id,
+      ];
+      _resetting = _reviews
+          .reset(cardIds, at)
+          .then((_) => (cardIds: cardIds, at: at));
+      await _resetting;
+      add(const StudysetListEventProgressRefreshRequested());
+    });
+    on<StudysetListEventResetUndone>((event, emit) async {
+      final resetting = _resetting;
+      _resetting = null;
+      if (resetting != null) {
+        final (:cardIds, :at) = await resetting;
+        await _reviews.undoReset(cardIds, at);
+        add(const StudysetListEventProgressRefreshRequested());
+      }
+    });
   }
 
+  /// The last fresh start, which an undo takes back.
+  Future<({List<String> cardIds, DateTime at})>? _resetting;
+
   /// How often the progress was asked for, so that a slow, older working
   /// out never overwrites a newer one.
   var _progressRequests = 0;

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

@@ -8,6 +8,7 @@ import 'package:halkyon_learn_flutter/src/core/editor/rich_content_view.dart';
 import 'package:halkyon_learn_flutter/src/core/layout/window_size.dart';
 import 'package:halkyon_learn_flutter/src/core/router/route_paths.dart';
 import 'package:halkyon_learn_flutter/src/core/widget/adaptive_sheet.dart';
+import 'package:halkyon_learn_flutter/src/core/widget/confirm_dialog.dart';
 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';
@@ -481,6 +482,7 @@ class const _StudyBar({
 enum _Option() {
   edit,
   move,
+  reset,
   archive,
   unarchive,
   delete,
@@ -555,6 +557,26 @@ class const _Options({
     );
   }
 
+  Future<void> _reset(BuildContext context) async {
+    final l10n = AppLocalizations.of(context);
+    final bloc = context.read<StudysetListBloc>();
+    if (!await confirmDestructiveAction(
+          context,
+          title: l10n.studysetResetTitle,
+          message: l10n.studysetResetMessage,
+          confirmLabel: l10n.studysetResetConfirm,
+        ) ||
+        !context.mounted) {
+      return;
+    }
+    bloc.add(StudysetListEventResetRequested(studyset.id));
+    showUndoSnackBar(
+      context,
+      message: l10n.studysetResetDone,
+      onUndo: () => bloc.add(const StudysetListEventResetUndone()),
+    );
+  }
+
   /// Back to where the person came from; to the studyset it sat in, or to
   /// the library, when they came straight here.
   void _leave(BuildContext context) {
@@ -587,6 +609,7 @@ class const _Options({
       onSelected: (option) => switch (option) {
         _Option.edit => _edit(context),
         _Option.move => _move(context),
+        _Option.reset => _reset(context),
         _Option.archive => _archive(context, archive: true),
         _Option.unarchive => _archive(context, archive: false),
         _Option.delete => deleteStudysetWithUndo(
@@ -598,6 +621,7 @@ class const _Options({
       itemBuilder: (context) => [
         item(_Option.edit, LucideIcons.pencil, l10n.studysetMenuEdit),
         item(_Option.move, LucideIcons.folderInput, l10n.studysetMenuMove),
+        item(_Option.reset, LucideIcons.rotateCcw, l10n.studysetMenuReset),
         if (studyset.isArchived)
           item(
             _Option.unarchive,

halkyon_learn_flutter/test/feature/studyset/bloc/studyset_list_bloc_test.dart

@@ -3,6 +3,7 @@ import 'package:halkyon_learn_flutter/src/core/content/rich_content.dart';
 import 'package:halkyon_learn_flutter/src/feature/card/data/card_repository.dart';
 import 'package:halkyon_learn_flutter/src/feature/card/model/card_content.dart';
 import 'package:halkyon_learn_flutter/src/feature/study/data/review_repository.dart';
+import 'package:halkyon_learn_flutter/src/feature/study/model/rating.dart';
 import 'package:halkyon_learn_flutter/src/feature/study/model/study_progress.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/bloc/studyset_list_bloc.dart';
 import 'package:halkyon_learn_flutter/src/feature/studyset/data/studyset_deletions.dart';
@@ -21,6 +22,7 @@ void main() {
   late FakeCardGateway cardGateway;
   late CardRepository cards;
   late StudysetDeletions deletions;
+  late ReviewRepository reviews;
   late StudysetListBloc bloc;
 
   setUp(() {
@@ -28,6 +30,7 @@ void main() {
     studysets = StudysetRepository(gateway);
     cardGateway = FakeCardGateway();
     cards = CardRepository(cardGateway);
+    reviews = ReviewRepository(FakeReviewGateway());
   });
   tearDown(() async {
     await bloc.close();
@@ -45,7 +48,7 @@ void main() {
     bloc = StudysetListBloc(
       studysets,
       cards,
-      ReviewRepository(FakeReviewGateway()),
+      reviews,
       deletions,
       parentId: parentId,
     )..add(const StudysetListEventStarted());
@@ -337,4 +340,33 @@ void main() {
       await listing(['Kanji', 'Kana']);
     });
   });
+
+  test('resetting starts the progress of a studyset and what is inside it '
+      'afresh; an undo takes it back', () async {
+    final japanese = await studysets.create(StudysetContent.titled('Japanese'));
+    final kanji = await studysets.create(
+      StudysetContent.titled('Kanji'),
+      parentId: japanese,
+    );
+    for (final studyset in [japanese, kanji]) {
+      final id = await cards.create(studyset, newCard());
+      await reviews.record(
+        cardId: id,
+        rating: Rating.easy,
+        reviewedAt: DateTime.now().toUtc(),
+        duration: Duration.zero,
+      );
+    }
+    start();
+    Future<int> dueIn(String id) async => (await bloc.stream.firstWhere(
+      (s) => s is StudysetListStateLoaded && s.progress.containsKey(id),
+    ) as StudysetListStateLoaded).progress[id]!.due;
+    await listing(['Japanese']);
+
+    bloc.add(StudysetListEventResetRequested(japanese));
+    expect(await dueIn(japanese), 2);
+
+    bloc.add(const StudysetListEventResetUndone());
+    expect(await dueIn(japanese), 0);
+  });
 }

halkyon_learn_flutter/test/support/fake_review_gateway.dart

@@ -27,6 +27,15 @@ class FakeReviewGateway() implements ReviewGateway {
     }
   }
 
+  @override
+  Future<void> deleteResets(Set<String> cardIds, DateTime at) async =>
+      rows.removeWhere(
+        (row) =>
+            cardIds.contains(row.cardId) &&
+            row.mode == 'reset' &&
+            row.reviewedAt == at,
+      );
+
   @override
   Stream<void> get remoteChanges => const Stream.empty();
 }