v1

lib/main.dart

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+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import 'package:sqflite_common_ffi/sqflite_ffi.dart';
+import 'src/services/deck_repository.dart';
+import 'src/screens/start_screen.dart';
+
+void main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+
+  if (!kIsWeb &&
+      (defaultTargetPlatform == TargetPlatform.windows ||
+          defaultTargetPlatform == TargetPlatform.linux ||
+          defaultTargetPlatform == TargetPlatform.macOS)) {
+    sqfliteFfiInit();
+    databaseFactory = databaseFactoryFfi;
+  }
+
+  runApp(
+    Provider<DeckRepository>(
+      create: (_) => DeckRepository(),
+      child: const WkApp(),
+    ),
+  );
+}
+
+class WkApp extends StatelessWidget {
+  const WkApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'WaniKani SRS',
+      debugShowCheckedModeBanner: false,
+      theme: ThemeData.dark(useMaterial3: true),
+      home: const StartScreen(),
+    );
+  }
+}

lib/src/api/wk_client.dart

@@ -0,0 +1,54 @@
+import 'dart:convert';
+import 'package:http/http.dart' as http;
+
+class WkClient {
+  final String apiKey;
+  final Map<String, String> headers;
+  final String base = 'https://api.wanikani.com/v2';
+
+  WkClient(this.apiKey) : headers = {'Authorization': 'Bearer $apiKey', 'Wanikani-Revision': '20170710', 'Accept': 'application/json'};
+
+  Future<List<Map<String, dynamic>>> fetchAllAssignments({List<String>? subjectTypes}) async {
+    final out = <Map<String, dynamic>>[];
+    String url = '$base/assignments?page=1';
+    if (subjectTypes != null && subjectTypes.isNotEmpty) {
+      final types = subjectTypes.join(',');
+      url = '$base/assignments?subject_types=$types&page=1';
+    }
+    while (url.isNotEmpty) {
+      final resp = await http.get(Uri.parse(url), headers: headers);
+      if (resp.statusCode != 200) throw Exception('API ${resp.statusCode}');
+      final j = json.decode(resp.body) as Map<String, dynamic>;
+      out.addAll((j['data'] as List).cast<Map<String, dynamic>>());
+      final pages = j['pages'] as Map<String, dynamic>?;
+      if (pages != null && pages['next_url'] != null) {
+        url = pages['next_url'] as String;
+      } else {
+        break;
+      }
+    }
+    return out;
+  }
+
+  Future<List<Map<String, dynamic>>> fetchSubjectsByIds(List<int> ids) async {
+    final out = <Map<String, dynamic>>[];
+    const batch = 100;
+    for (var i = 0; i < ids.length; i += batch) {
+      final chunk = ids.sublist(i, i + batch > ids.length ? ids.length : i + batch);
+      String url = '$base/subjects?ids=${chunk.join(',')}&page=1';
+      while (true) {
+        final resp = await http.get(Uri.parse(url), headers: headers);
+        if (resp.statusCode != 200) throw Exception('API ${resp.statusCode}');
+        final j = json.decode(resp.body) as Map<String, dynamic>;
+        out.addAll((j['data'] as List).cast<Map<String, dynamic>>());
+        final pages = j['pages'] as Map<String, dynamic>?;
+        if (pages != null && pages['next_url'] != null) {
+          url = pages['next_url'] as String;
+        } else {
+          break;
+        }
+      }
+    }
+    return out;
+  }
+}

lib/src/app.dart

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+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import 'screens/home_screen.dart';
+import 'services/deck_repository.dart';
+
+class WkApp extends StatelessWidget {
+  const WkApp({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MultiProvider(
+      providers: [
+        Provider<DeckRepository>(create: (_) => DeckRepository()),
+      ],
+      child: MaterialApp(
+        title: 'WaniKani SRS',
+        theme: ThemeData(useMaterial3: true, colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple)),
+        home: const HomeScreen(),
+      ),
+    );
+  }
+}

lib/src/models/kanji_item.dart

@@ -0,0 +1,62 @@
+class KanjiItem {
+  final int id;
+  final String characters;
+  final List<String> meanings;
+  final List<String> onyomi;
+  final List<String> kunyomi;
+
+  KanjiItem({
+    required this.id,
+    required this.characters,
+    required this.meanings,
+    required this.onyomi,
+    required this.kunyomi,
+  });
+
+  factory KanjiItem.fromSubject(Map<String, dynamic> subj) {
+    final int id = subj['id'] as int;
+    final data = subj['data'] as Map<String, dynamic>;
+    final String characters = (data['characters'] ?? '') as String;
+    final List<String> meanings = <String>[];
+    final List<String> onyomi = <String>[];
+    final List<String> kunyomi = <String>[];
+
+    if (data['meanings'] != null) {
+      for (final m in data['meanings'] as List) {
+        meanings.add((m['meaning'] as String).toLowerCase());
+      }
+    }
+
+    if (data['readings'] != null) {
+      for (final r in data['readings'] as List) {
+        final typ = r['type'] as String? ?? '';
+        final reading = r['reading'] as String? ?? '';
+        if (typ == 'onyomi') {
+          onyomi.add(_katakanaToHiragana(reading));
+        } else if (typ == 'kunyomi') {
+          kunyomi.add(reading);
+        }
+      }
+    }
+
+    return KanjiItem(
+      id: id,
+      characters: characters,
+      meanings: meanings,
+      onyomi: onyomi,
+      kunyomi: kunyomi,
+    );
+  }
+}
+
+String _katakanaToHiragana(String input) {
+  final buf = StringBuffer();
+  for (final r in input.runes) {
+    if (r >= 0x30A1 && r <= 0x30FA) {
+      buf.writeCharCode(r - 0x60);
+    } else {
+      buf.writeCharCode(r);
+    }
+  }
+  return buf.toString();
+}

lib/src/screens/home_screen.dart

@@ -0,0 +1,310 @@
+import 'dart:math';
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import '../models/kanji_item.dart';
+import '../services/deck_repository.dart';
+import '../services/distractor_generator.dart';
+import '../widgets/kanji_card.dart';
+import '../widgets/options_grid.dart';
+import 'settings_screen.dart';
+
+enum QuizMode { kanjiToEnglish, englishToKanji, reading }
+
+class _ReadingInfo {
+  final List<String> correctReadings;
+  final String hint;
+
+  _ReadingInfo(this.correctReadings, this.hint);
+}
+
+class HomeScreen extends StatefulWidget {
+  const HomeScreen({super.key});
+
+  @override
+  State<HomeScreen> createState() => _HomeScreenState();
+}
+
+class _HomeScreenState extends State<HomeScreen> {
+  List<KanjiItem> _deck = [];
+  bool _loading = false;
+  String _status = 'Loading deck...';
+  final DistractorGenerator _dg = DistractorGenerator();
+  final Random _random = Random();
+
+  QuizMode _mode = QuizMode.kanjiToEnglish;
+  KanjiItem? _current;
+  List<String> _options = [];
+  List<String> _correctAnswers = [];
+  String _readingHint = '';
+  int _score = 0;
+  int _asked = 0;
+
+  @override
+  void initState() {
+    super.initState();
+    _loadDeck();
+  }
+
+  Future<void> _loadDeck() async {
+    setState(() {
+      _loading = true;
+      _status = 'Loading deck...';
+    });
+
+    try {
+      final repo = Provider.of<DeckRepository>(context, listen: false);
+      await repo.loadApiKey();
+      final apiKey = repo.apiKey;
+
+      if (apiKey == null || apiKey.isEmpty) {
+        if (mounted) {
+          Navigator.of(context).pushReplacement(
+            MaterialPageRoute(builder: (_) => const SettingsScreen()),
+          );
+        }
+        return;
+      }
+
+      setState(() {
+        _status = 'Fetching deck...';
+      });
+
+      final items = await repo.fetchAndCacheFromWk(apiKey);
+
+      setState(() {
+        _deck = items;
+        _status = 'Loaded ${items.length} kanji';
+        _loading = false;
+      });
+
+      _nextQuestion();
+    } catch (e) {
+      setState(() {
+        _status = 'Error: $e';
+        _loading = false;
+      });
+    }
+  }
+
+  String _toTitleCase(String s) {
+    if (s.isEmpty) return s;
+    return s
+        .split(' ')
+        .map((w) => w.isEmpty ? w : w[0].toUpperCase() + w.substring(1))
+        .join(' ');
+  }
+
+  _ReadingInfo _pickReading(KanjiItem item) {
+    final choices = <String>[];
+    if (item.onyomi.isNotEmpty) choices.add('onyomi');
+    if (item.kunyomi.isNotEmpty) choices.add('kunyomi');
+    if (choices.isEmpty) return _ReadingInfo([], '');
+
+    final pickedType = choices[_random.nextInt(choices.length)];
+    final readingsList = pickedType == 'onyomi' ? item.onyomi : item.kunyomi;
+    final hint = 'Select the ${pickedType == 'onyomi' ? "on\'yomi" : "kunyomi"}';
+
+    return _ReadingInfo(readingsList, hint);
+  }
+
+  void _nextQuestion() {
+    if (_deck.isEmpty) return;
+    _current = (_deck..shuffle()).first;
+
+    _correctAnswers = [];
+    _options = [];
+    _readingHint = '';
+
+    switch (_mode) {
+      case QuizMode.kanjiToEnglish:
+        _correctAnswers = [_current!.meanings.first];
+        _options = [_correctAnswers.first, ..._dg.generateMeanings(_current!, _deck, 3)]
+            .map(_toTitleCase)
+            .toList()
+          ..shuffle();
+        break;
+
+      case QuizMode.englishToKanji:
+        _correctAnswers = [_current!.characters];
+        _options = [_correctAnswers.first, ..._dg.generateKanji(_current!, _deck, 3)]
+          ..shuffle();
+        break;
+
+      case QuizMode.reading:
+        final info = _pickReading(_current!);
+        _correctAnswers = info.correctReadings;
+        _readingHint = info.hint;
+
+        final readingsSource = _readingHint.contains("on'yomi")
+            ? _deck.expand((k) => k.onyomi)
+            : _deck.expand((k) => k.kunyomi);
+
+        final distractors =
+        readingsSource.where((r) => !_correctAnswers.contains(r)).toSet().toList()
+          ..shuffle();
+        _options = ([_correctAnswers[_random.nextInt(_correctAnswers.length)], ...distractors.take(3)])
+          ..shuffle();
+        break;
+    }
+
+    setState(() {});
+  }
+
+  void _answer(String option) {
+    final isCorrect = _correctAnswers
+        .map((a) => a.toLowerCase().trim())
+        .contains(option.toLowerCase().trim());
+    setState(() {
+      _asked += 1;
+      if (isCorrect) _score += 1;
+    });
+
+    final correctDisplay = (_mode == QuizMode.kanjiToEnglish)
+        ? _toTitleCase(_correctAnswers.first)
+        : (_mode == QuizMode.reading ? _correctAnswers.join(', ') : _correctAnswers.first);
+
+    final snack = SnackBar(
+      content: Text(
+        isCorrect ? 'Correct!' : 'Wrong — correct: $correctDisplay',
+        style: TextStyle(
+          color: isCorrect ? Colors.greenAccent : Colors.redAccent,
+          fontWeight: FontWeight.bold,
+        ),
+      ),
+      backgroundColor: const Color(0xFF222222),
+      duration: const Duration(milliseconds: 900),
+    );
+    ScaffoldMessenger.of(context).showSnackBar(snack);
+
+    Future.delayed(const Duration(milliseconds: 900), _nextQuestion);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    String prompt = '';
+    String subtitle = '';
+
+    switch (_mode) {
+      case QuizMode.kanjiToEnglish:
+        prompt = _current?.characters ?? '';
+        break;
+      case QuizMode.englishToKanji:
+        prompt = _current != null ? _toTitleCase(_current!.meanings.first) : '';
+        break;
+      case QuizMode.reading:
+        prompt = _current?.characters ?? '';
+        subtitle = _readingHint;
+        break;
+    }
+
+    return Scaffold(
+      backgroundColor: const Color(0xFF121212),
+      appBar: AppBar(
+        title: const Text('WaniKani Kanji SRS'),
+        backgroundColor: const Color(0xFF1F1F1F),
+        foregroundColor: Colors.white,
+        elevation: 2,
+        actions: [
+          IconButton(
+            icon: const Icon(Icons.settings),
+            onPressed: () {
+              Navigator.of(context).push(
+                MaterialPageRoute(builder: (_) => const SettingsScreen()),
+              );
+            },
+          )
+        ],
+      ),
+      body: Padding(
+        padding: const EdgeInsets.all(16.0),
+        child: Column(
+          children: [
+            Row(
+              children: [
+                Expanded(
+                  child: Text(
+                    _status,
+                    style: const TextStyle(color: Colors.white),
+                  ),
+                ),
+                if (_loading)
+                  const CircularProgressIndicator(color: Colors.blueAccent),
+              ],
+            ),
+            const SizedBox(height: 12),
+
+            Wrap(
+              spacing: 6,
+              runSpacing: 4,
+              alignment: WrapAlignment.center,
+              children: [
+                _buildChoiceChip('Kanji→English', QuizMode.kanjiToEnglish),
+                _buildChoiceChip('English→Kanji', QuizMode.englishToKanji),
+                _buildChoiceChip('Reading', QuizMode.reading),
+              ],
+            ),
+
+            const SizedBox(height: 18),
+
+            Expanded(
+              flex: 3,
+              child: Center(
+                child: ConstrainedBox(
+                  constraints: const BoxConstraints(
+                    minWidth: 0,
+                    maxWidth: 500,
+                    minHeight: 150,
+                  ),
+                  child: KanjiCard(
+                    characters: prompt,
+                    subtitle: subtitle,
+                    backgroundColor: const Color(0xFF1E1E1E),
+                    textColor: Colors.white,
+                  ),
+                ),
+              ),
+            ),
+
+            const SizedBox(height: 12),
+
+            SafeArea(
+              top: false,
+              child: Column(
+                children: [
+                  OptionsGrid(
+                    options: _options,
+                    onSelected: _answer,
+                    buttonColor: const Color(0xFF1E1E1E),
+                    textColor: Colors.white,
+                  ),
+                  const SizedBox(height: 8),
+                  Text(
+                    'Score: $_score / $_asked',
+                    style: const TextStyle(color: Colors.white),
+                  ),
+                ],
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+  ChoiceChip _buildChoiceChip(String label, QuizMode mode) {
+    final selected = _mode == mode;
+    return ChoiceChip(
+      label: Text(
+        label,
+        style: TextStyle(color: selected ? Colors.white : Colors.grey[400]),
+      ),
+      selected: selected,
+      onSelected: (v) {
+        setState(() => _mode = mode);
+        _nextQuestion();
+      },
+      selectedColor: Colors.blueAccent,
+      backgroundColor: const Color(0xFF1E1E1E),
+    );
+  }
+}

lib/src/screens/settings_screen.dart

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+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import '../services/deck_repository.dart';
+import 'home_screen.dart';
+
+class SettingsScreen extends StatefulWidget {
+  const SettingsScreen({super.key});
+
+  @override
+  State<SettingsScreen> createState() => _SettingsScreenState();
+}
+
+class _SettingsScreenState extends State<SettingsScreen> {
+  final TextEditingController _apiKeyController = TextEditingController();
+
+  @override
+  void dispose() {
+    _apiKeyController.dispose();
+    super.dispose();
+  }
+
+  Future<void> _saveApiKey() async {
+    final apiKey = _apiKeyController.text.trim();
+    if (apiKey.isEmpty) return;
+
+    final repo = Provider.of<DeckRepository>(context, listen: false);
+    await repo.setApiKey(apiKey);
+
+    ScaffoldMessenger.of(context).showSnackBar(
+      const SnackBar(content: Text('API key saved!')),
+    );
+
+    if (mounted) {
+      Navigator.of(context).pushReplacement(
+        MaterialPageRoute(builder: (_) => const HomeScreen()),
+      );
+    }
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    final repo = Provider.of<DeckRepository>(context, listen: false);
+    repo.loadApiKey().then((key) {
+      if (key != null) {
+        _apiKeyController.text = key;
+      }
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      backgroundColor: const Color(0xFF121212),
+      appBar: AppBar(
+        title: const Text('Settings'),
+        backgroundColor: const Color(0xFF1F1F1F),
+        foregroundColor: Colors.white,
+      ),
+      body: Padding(
+        padding: const EdgeInsets.all(16.0),
+        child: Column(
+          children: [
+            TextField(
+              controller: _apiKeyController,
+              obscureText: true,
+              style: const TextStyle(color: Colors.white),
+              decoration: InputDecoration(
+                labelText: 'WaniKani API Key',
+                labelStyle: const TextStyle(color: Colors.grey),
+                filled: true,
+                fillColor: const Color(0xFF1E1E1E),
+                border: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(6),
+                  borderSide: const BorderSide(color: Colors.grey),
+                ),
+              ),
+            ),
+            const SizedBox(height: 16),
+            ElevatedButton(
+              onPressed: _saveApiKey,
+              style: ElevatedButton.styleFrom(
+                backgroundColor: Colors.blueAccent,
+                foregroundColor: Colors.white,
+              ),
+              child: const Text('Save & Start Quiz'),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}

lib/src/screens/start_screen.dart

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+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import '../services/deck_repository.dart';
+import 'settings_screen.dart';
+import 'home_screen.dart';
+
+class StartScreen extends StatefulWidget {
+  const StartScreen({super.key});
+
+  @override
+  State<StartScreen> createState() => _StartScreenState();
+}
+
+class _StartScreenState extends State<StartScreen> {
+  bool _loading = true;
+  bool _hasApiKey = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _checkApiKey();
+  }
+
+  Future<void> _checkApiKey() async {
+    final repo = Provider.of<DeckRepository>(context, listen: false);
+    await repo.loadApiKey();
+    setState(() {
+      _hasApiKey = repo.apiKey != null && repo.apiKey!.isNotEmpty;
+      _loading = false;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (_loading) {
+      return const Scaffold(
+        backgroundColor: Color(0xFF121212),
+        body: Center(
+          child: CircularProgressIndicator(color: Colors.blueAccent),
+        ),
+      );
+    }
+
+    return Scaffold(
+      backgroundColor: const Color(0xFF121212),
+      body: Center(
+        child: Padding(
+          padding: const EdgeInsets.all(32),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              Text(
+                'Welcome to WaniKani Kanji SRS!',
+                style: Theme.of(context)
+                    .textTheme
+                    .headlineMedium
+                    ?.copyWith(fontSize: 28, color: Colors.white),
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: 16),
+              Text(
+                _hasApiKey
+                    ? 'Your API key is set. You can start the quiz!'
+                    : 'Before you start, please set up your WaniKani API key in the settings.',
+                style: Theme.of(context)
+                    .textTheme
+                    .bodyMedium
+                    ?.copyWith(color: Colors.grey[300]),
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: 32),
+              ElevatedButton(
+                onPressed: () {
+                  if (_hasApiKey) {
+                    Navigator.of(context).pushReplacement(
+                      MaterialPageRoute(builder: (_) => const HomeScreen()),
+                    );
+                  } else {
+                    Navigator.of(context).push(
+                      MaterialPageRoute(builder: (_) => const SettingsScreen()),
+                    );
+                  }
+                },
+                style: ElevatedButton.styleFrom(
+                  backgroundColor: Colors.blueAccent,
+                  foregroundColor: Colors.white,
+                  padding: const EdgeInsets.symmetric(horizontal: 32, vertical: 16),
+                  shape: RoundedRectangleBorder(
+                      borderRadius: BorderRadius.circular(12)),
+                ),
+                child: Text(
+                  _hasApiKey ? 'Start Quiz' : 'Go to Settings',
+                  style: const TextStyle(fontSize: 18),
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/src/services/deck_repository.dart

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+import 'dart:async';
+import 'package:path/path.dart';
+import 'package:path_provider/path_provider.dart';
+import 'package:sqflite/sqflite.dart';
+import '../models/kanji_item.dart';
+import '../api/wk_client.dart';
+
+class DeckRepository {
+  Database? _db;
+  String? _apiKey;
+
+  Future<void> setApiKey(String apiKey) async {
+    _apiKey = apiKey;
+    await saveApiKey(apiKey);
+  }
+
+  String? get apiKey => _apiKey;
+
+  Future<Database> _openDb() async {
+    if (_db != null) return _db!;
+    final dir = await getApplicationDocumentsDirectory();
+    final path = join(dir.path, 'wanikani_srs.db');
+
+    _db = await openDatabase(
+      path,
+      version: 2,
+      onCreate: (db, version) async {
+        await db.execute(
+            '''CREATE TABLE kanji (id INTEGER PRIMARY KEY, characters TEXT, meanings TEXT, onyomi TEXT, kunyomi TEXT)''');
+        await db.execute(
+            '''CREATE TABLE settings (key TEXT PRIMARY KEY, value TEXT)''');
+      },
+      onUpgrade: (db, oldVersion, newVersion) async {
+        await db.execute(
+            '''CREATE TABLE IF NOT EXISTS settings (key TEXT PRIMARY KEY, value TEXT)''');
+      },
+    );
+
+    return _db!;
+  }
+
+  Future<void> saveApiKey(String apiKey) async {
+    final db = await _openDb();
+    await db.insert(
+      'settings',
+      {'key': 'apiKey', 'value': apiKey},
+      conflictAlgorithm: ConflictAlgorithm.replace,
+    );
+  }
+
+  Future<String?> loadApiKey() async {
+    final db = await _openDb();
+    final rows =
+    await db.query('settings', where: 'key = ?', whereArgs: ['apiKey']);
+    if (rows.isNotEmpty) {
+      _apiKey = rows.first['value'] as String;
+      return _apiKey;
+    }
+    return null;
+  }
+
+  Future<void> saveKanji(List<KanjiItem> items) async {
+    final db = await _openDb();
+    final batch = db.batch();
+    for (final it in items) {
+      batch.insert(
+        'kanji',
+        {
+          'id': it.id,
+          'characters': it.characters,
+          'meanings': it.meanings.join('|'),
+          'onyomi': it.onyomi.join('|'),
+          'kunyomi': it.kunyomi.join('|'),
+        },
+        conflictAlgorithm: ConflictAlgorithm.replace,
+      );
+    }
+    await batch.commit(noResult: true);
+  }
+
+  Future<List<KanjiItem>> loadKanji() async {
+    final db = await _openDb();
+    final rows = await db.query('kanji');
+    return rows
+        .map((r) => KanjiItem(
+      id: r['id'] as int,
+      characters: r['characters'] as String,
+      meanings: (r['meanings'] as String)
+          .split('|')
+          .where((s) => s.isNotEmpty)
+          .toList(),
+      onyomi: (r['onyomi'] as String)
+          .split('|')
+          .where((s) => s.isNotEmpty)
+          .toList(),
+      kunyomi: (r['kunyomi'] as String)
+          .split('|')
+          .where((s) => s.isNotEmpty)
+          .toList(),
+    ))
+        .toList();
+  }
+
+  Future<List<KanjiItem>> fetchAndCacheFromWk([String? apiKey]) async {
+    final key = apiKey ?? _apiKey;
+    if (key == null) throw Exception('API key not set');
+
+    final client = WkClient(key);
+    final assignments =
+    await client.fetchAllAssignments(subjectTypes: ['kanji']);
+
+    final unlocked = <int>{};
+    for (final a in assignments) {
+      final data = a['data'] as Map<String, dynamic>;
+      final sidRaw = data['subject_id'];
+      if (sidRaw == null) continue;
+      final sid = sidRaw is int ? sidRaw : int.tryParse(sidRaw.toString());
+      if (sid == null) continue;
+      final started = data['started_at'];
+      final srs = data['srs_stage'];
+      final isUnlocked = (started != null) || (srs != null && (srs as int) > 0);
+      if (isUnlocked) unlocked.add(sid);
+    }
+
+    if (unlocked.isEmpty) return [];
+
+    final subjects = await client.fetchSubjectsByIds(unlocked.toList());
+    final items = subjects
+        .where((s) =>
+    s['object'] == 'kanji' ||
+        (s['data'] != null &&
+            (s['data'] as Map)['object_type'] == 'kanji'))
+        .map((s) => KanjiItem.fromSubject(s))
+        .where((k) => k.characters.isNotEmpty && k.meanings.isNotEmpty)
+        .toList();
+
+    await saveKanji(items);
+    return items;
+  }
+}

lib/src/services/distractor_generator.dart

@@ -0,0 +1,69 @@
+import '../models/kanji_item.dart';
+import 'dart:math';
+
+class DistractorGenerator {
+  final Random _rnd = Random();
+
+  List<String> generateMeanings(KanjiItem correct, List<KanjiItem> pool, int needed) {
+    final correctMeaning = correct.meanings.first;
+    final tokens = correctMeaning.split(RegExp(r'\s+')).map((s) => s.trim()).where((s) => s.isNotEmpty).toSet();
+    final candidates = <String>[];
+    for (final k in pool) {
+      if (k.id == correct.id) continue;
+      for (final m in k.meanings) {
+        final mTokens = m.split(RegExp(r'\s+')).map((s) => s.trim()).where((s) => s.isNotEmpty).toSet();
+        if (mTokens.intersection(tokens).isNotEmpty) {
+          candidates.add(m);
+        }
+      }
+    }
+    if (candidates.length < needed) {
+      for (final k in pool) {
+        if (k.id == correct.id) continue;
+        for (final m in k.meanings) {
+          if (!candidates.contains(m)) candidates.add(m);
+        }
+      }
+    }
+    candidates.shuffle(_rnd);
+    final out = <String>[];
+    for (final c in candidates) {
+      if (out.length >= needed) break;
+      if (c.toLowerCase() == correctMeaning.toLowerCase()) continue;
+      out.add(_toTitleCase(c));
+    }
+    while (out.length < needed) out.add('(no more)');
+    return out;
+  }
+
+  List<String> generateKanji(KanjiItem correct, List<KanjiItem> pool, int needed) {
+    final others = pool.map((k) => k.characters).where((c) => c != correct.characters).toList();
+    others.shuffle(_rnd);
+    final out = <String>[];
+    for (final o in others) {
+      if (out.length >= needed) break;
+      out.add(o);
+    }
+    while (out.length < needed) out.add('—');
+    return out;
+  }
+
+  List<String> generateReadings(String correct, List<KanjiItem> pool, int needed) {
+    final poolReadings = <String>[];
+    for (final k in pool) {
+      poolReadings.addAll(k.onyomi);
+      poolReadings.addAll(k.kunyomi);
+    }
+    poolReadings.removeWhere((r) => r == correct || r.isEmpty);
+    poolReadings.shuffle(_rnd);
+    final out = <String>[];
+    for (final r in poolReadings) {
+      if (out.length >= needed) break;
+      out.add(r);
+    }
+    while (out.length < needed) out.add('—');
+    return out;
+  }
+}
+
+String _toTitleCase(String s) => s.split(' ').map((w) => w.isEmpty ? w : (w[0].toUpperCase() + w.substring(1))).join(' ');

lib/src/widgets/kanji_card.dart

@@ -0,0 +1,57 @@
+import 'package:flutter/material.dart';
+
+class KanjiCard extends StatelessWidget {
+  final String characters;
+  final String subtitle;
+  final Color? backgroundColor;
+  final Color? textColor;
+
+  const KanjiCard({
+    super.key,
+    required this.characters,
+    this.subtitle = '',
+    this.backgroundColor,
+    this.textColor,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final bgColor = backgroundColor ?? theme.cardTheme.color ?? theme.colorScheme.surface;
+    final fgColor = textColor ?? theme.textTheme.bodyMedium?.color ?? theme.colorScheme.onSurface;
+
+    return Card(
+      elevation: theme.cardTheme.elevation ?? 12,
+      color: bgColor,
+      shape: theme.cardTheme.shape ?? RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
+      child: SizedBox(
+        width: 360,
+        height: 240,
+        child: Padding(
+          padding: const EdgeInsets.all(20),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              Text(
+                characters,
+                style: theme.textTheme.headlineMedium?.copyWith(
+                  fontSize: 56,
+                  color: fgColor,
+                ),
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: 8),
+              Text(
+                subtitle,
+                style: theme.textTheme.bodyMedium?.copyWith(
+                  color: fgColor.withOpacity(0.7),
+                ),
+                textAlign: TextAlign.center,
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/src/widgets/options_grid.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/material.dart';
+
+class OptionsGrid extends StatelessWidget {
+  final List<String> options;
+  final void Function(String) onSelected;
+  final Color? buttonColor;
+  final Color? textColor;
+
+  const OptionsGrid({
+    super.key,
+    required this.options,
+    required this.onSelected,
+    this.buttonColor,
+    this.textColor,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    if (options.isEmpty) return const SizedBox.shrink();
+
+    final theme = Theme.of(context);
+    final bg = buttonColor ?? theme.colorScheme.primary;
+    final fg = textColor ?? theme.colorScheme.onPrimary;
+
+    return Wrap(
+      spacing: 10,
+      runSpacing: 10,
+      alignment: WrapAlignment.center,
+      children: options.map((o) {
+        return SizedBox(
+          width: 160,
+          child: ElevatedButton(
+            onPressed: () => onSelected(o),
+            style: ElevatedButton.styleFrom(
+              backgroundColor: bg,
+              foregroundColor: fg,
+              shape: RoundedRectangleBorder(
+                borderRadius: BorderRadius.circular(12),
+              ),
+              padding: const EdgeInsets.symmetric(vertical: 16, horizontal: 8),
+            ),
+            child: Text(
+              o,
+              style: TextStyle(fontSize: 20, color: fg),
+              textAlign: TextAlign.center,
+            ),
+          ),
+        );
+      }).toList(),
+    );
+  }
+}