fix(explore): a study button in a copy studies the copy's studyset

A study button names the studyset it studies by its id. Copied from a
release or an archive, the studysets get new ids, and a button in the
content kept naming the author's (or the archive's), which the person
doesn't have: it studied nothing. The copier now writes the content after
the studysets, each study button naming the studyset made of the one it
named; only a study button's studyset, as a short id could also be a word
of the content.

A later release taken into a copy still brings the author's ids into its
buttons: the copy updater doesn't rename them yet.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/lib/src/feature/explore/data/release_copier.dart

@@ -2,6 +2,7 @@ import 'dart:convert';
 import 'dart:typed_data';
 
 import 'package:halkyon_learn_flutter/src/core/asset/data/asset_repository.dart';
+import 'package:halkyon_learn_flutter/src/core/content/content_blocks.dart';
 import 'package:halkyon_learn_flutter/src/core/content/published_ref.dart';
 import 'package:halkyon_learn_flutter/src/feature/card/data/card_payload.dart';
 import 'package:halkyon_learn_flutter/src/feature/card/data/card_repository.dart';
@@ -166,14 +167,26 @@ class ReleaseCopier(
       step();
     }
 
+    // Content naming a studyset of the release (a study button) names the
+    // one made of it now, as it names the person's own files.
+    final named = _read(
+      release,
+      assetIds,
+      studysetIds: {
+        for (final MapEntry(key: directory, value: item)
+            in read.studysets.entries)
+          item.id: studysetIds[directory]!,
+      },
+    );
+
     final tagIds = <String, String>{};
     Future<Set<String>> tagsOf(List<String> names) async => {
       for (final name in names) tagIds[name] ??= await _tags.create(name),
     };
 
-    for (final directory in read.directories) {
+    for (final directory in named.directories) {
       final studysetId = studysetIds[directory]!;
-      final cards = _ordered(read.cards[directory]);
+      final cards = _ordered(named.cards[directory]);
       final cardIds = await _cards.createAll(studysetId, [
         for (final card in cards)
           if (origin == null)
@@ -191,7 +204,7 @@ class ReleaseCopier(
       done += cards.length;
       onProgress?.call(done / total);
 
-      for (final note in _ordered(read.notes[directory])) {
+      for (final note in _ordered(named.notes[directory])) {
         final (:noteId, revisionId: _) = await _notes.create(
           studysetId,
           origin == null
@@ -205,7 +218,7 @@ class ReleaseCopier(
         step();
       }
 
-      for (final path in _ordered(read.paths[directory])) {
+      for (final path in _ordered(named.paths[directory])) {
         final pathId = ids[path.id] = await _paths.createPath(
           studysetId,
           origin == null
@@ -216,7 +229,7 @@ class ReleaseCopier(
           await _tags.setTagsOfPath(pathId, await tagsOf(path.tags));
         }
         step();
-        for (final stepItem in _ordered(read.steps[path.id])) {
+        for (final stepItem in _ordered(named.steps[path.id])) {
           await _paths.createStep(
             pathId,
             stepItem.kind!,
@@ -231,7 +244,7 @@ class ReleaseCopier(
         }
       }
 
-      for (final pdf in _ordered(read.pdfs[directory])) {
+      for (final pdf in _ordered(named.pdfs[directory])) {
         await _pdfs.add(
           studysetId,
           origin == null
@@ -245,9 +258,15 @@ class ReleaseCopier(
   }
 
   /// [release]'s items decoded, each file of the release named by the
-  /// asset row [assetIds] gives its old one; throws [ReleaseUnreadable] for
+  /// asset row [assetIds] gives its old one, and each studyset of it a
-  /// an item this app can't read.
+  /// study button names by the one [studysetIds] gives (the content's only
-  _Read _read(PublishedRelease release, Map<String, String> assetIds) {
+  /// reference to a studyset); throws [ReleaseUnreadable] for an item this
+  /// app can't read.
+  _Read _read(
+    PublishedRelease release,
+    Map<String, String> assetIds, {
+    Map<String, String> studysetIds = const {},
+  }) {
     final read = _Read();
     try {
       for (final MapEntry(key: path, value: json) in release.items.entries) {
@@ -269,7 +288,7 @@ class ReleaseCopier(
             tag! as String,
         ];
         // The person's own files in place of the author's.
-        var text = jsonEncode(json['payload']);
+        var text = jsonEncode(_renamed(json['payload'], studysetIds));
         for (final MapEntry(key: old, value: own) in assetIds.entries) {
           text = text.replaceAll(old, own);
         }
@@ -348,6 +367,25 @@ class ReleaseCopier(
 
   static const _kinds = {'cards', 'notes', 'paths', 'pdfs'};
 
+  /// [json] with every studyset a study button names by the one [names]
+  /// gives in its place.
+  static Object? _renamed(Object? json, Map<String, String> names) =>
+      names.isEmpty
+      ? json
+      : switch (json) {
+          final List<Object?> list => [
+            for (final item in list) _renamed(item, names),
+          ],
+          final Map<String, Object?> map => {
+            for (final MapEntry(:key, :value) in map.entries)
+              key: switch ((key, value)) {
+                (studyButtonStudysetKey, final String id) => names[id] ?? id,
+                _ => _renamed(value, names),
+              },
+          },
+          _ => json,
+        };
+
   /// The directory of the studyset [directory] is in.
   static String _parentOf(String directory) => switch (directory.lastIndexOf(
     '/',

halkyon_learn_flutter/test/feature/archive/archive_test.dart

@@ -4,6 +4,7 @@ import 'dart:typed_data';
 import 'package:archive/archive.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:halkyon_learn_flutter/src/core/asset/data/asset_repository.dart';
+import 'package:halkyon_learn_flutter/src/core/content/content_blocks.dart';
 import 'package:halkyon_learn_flutter/src/core/content/rich_content.dart';
 import 'package:halkyon_learn_flutter/src/feature/archive/data/archive_importer.dart';
 import 'package:halkyon_learn_flutter/src/feature/archive/data/archive_reader.dart';
@@ -12,7 +13,12 @@ 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/dictionary/data/dictionary_repository.dart';
 import 'package:halkyon_learn_flutter/src/feature/explore/data/release_copier.dart';
+import 'package:halkyon_learn_flutter/src/feature/learning_path/data/learning_path_payload.dart';
 import 'package:halkyon_learn_flutter/src/feature/learning_path/data/learning_path_repository.dart';
+import 'package:halkyon_learn_flutter/src/feature/learning_path/data/learning_path_step_payload.dart';
+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/pdf_source/data/pdf_source_repository.dart';
 import 'package:halkyon_learn_flutter/src/feature/study/data/review_repository.dart';
@@ -163,13 +169,14 @@ void main() {
     late StudysetRepository studysets;
     late TagRepository tags;
     late ReviewRepository reviews;
+    late LearningPathRepository paths;
     late ArchiveImporter importer;
 
     setUp(() {
       studysets = StudysetRepository(FakeStudysetGateway());
       cards = CardRepository(FakeCardGateway());
       final notes = NoteRepository(FakeNoteGateway());
-      final paths = LearningPathRepository(FakeLearningPathGateway());
+      paths = LearningPathRepository(FakeLearningPathGateway());
       tags = TagRepository(
         FakeTagGateway(),
         cardChanges: cards.changes,
@@ -203,6 +210,57 @@ void main() {
       );
     });
 
+    test('content naming a studyset of the archive, as a study button '
+        'does, names it as it is in the library', () async {
+      final archive = {
+        ...japanese(),
+        'paths/drill/path.json': {
+          'id': 'drill',
+          'position': 'a0',
+          'payload': json(
+            encodeLearningPathPayload(LearningPathContent.titled('Drill')),
+          ),
+        },
+        'paths/drill/steps/go.json': {
+          'id': 'go',
+          'position': 'a0',
+          'kind': StepKind.info.value,
+          'payload': json(
+            encodeStepPayload(
+              StepContent.empty(StepKind.info).withField(
+                StepField.body,
+                RichContent({
+                  'document': {
+                    'type': 'page',
+                    'children': [
+                      {
+                        'type': studyButtonBlockType,
+                        'data': {studyButtonStudysetKey: 'vocabulary'},
+                      },
+                    ],
+                  },
+                }),
+              ),
+            ),
+          ),
+        },
+      };
+
+      await importer.import(readArchive(zip(archive)));
+
+      final vocabulary = (await studysets.all()).singleWhere(
+        (s) => s.content.title == 'Vocabulary',
+      );
+      final path = (await paths.pathsOf(
+        (await studysets.all()).singleWhere((s) => s.parentId == null).id,
+      )).single;
+      final step = (await paths.stepsOf(path.id)).single;
+      expect(
+        jsonEncode(step.content.body.toJson()),
+        contains('"$studyButtonStudysetKey":"${vocabulary.id}"'),
+      );
+    });
+
     test("brings the studysets and cards in as the person's own, a word "
         'from the dictionary as adding it makes it, the reviews onto the '
         'cards they were of; an entry the instance lacks is left out and '