add misc kanji utils

lib/screens/practise/flashcard.dart

@@ -1,123 +1,15 @@
-import 'dart:math';
 
 import 'package:tangocard_reader/components/flashcard.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter/services.dart';
 import 'package:tangocard_reader/models/data_entry.dart';
 
-class FlashcardView extends StatefulWidget {
-  final List<YokutangoEntry> cards;
-  final int? index;
-
-  const FlashcardView({
-    required this.cards,
-    this.index,
-    Key? key,
-  }) : super(key: key);
-
-  @override
-  _FlashcardViewState createState() => _FlashcardViewState();
-}
-
-const encouragingWords = [
-  '頑張れ〜！',
-  'できるぞ！',
-  'ヨッシャー！',
-  'いけいけいけー！',
-];
-
-class _FlashcardViewState extends State<FlashcardView> {
-  String title = '';
-  int currentCard = 0;
-  final List<bool> _isSelected = [false, false];
-
-  get isShuffleMode => _isSelected[0];
-  get isLanguageSwitchedMode => _isSelected[1];
-  get randomCard => Random().nextInt(widget.cards.length);
-
-  @override
-  void initState() {
-    title = encouragingWords[Random().nextInt(encouragingWords.length)];
-    currentCard = widget.index ?? 0;
-
-    final isPhone = MediaQueryData.fromWindow(WidgetsBinding.instance!.window)
-            .size
-            .shortestSide <
-        600;
-    if (isPhone) {
-      SystemChrome.setPreferredOrientations([
-        DeviceOrientation.landscapeLeft,
-        DeviceOrientation.landscapeRight,
-      ]);
-    }
-
-    super.initState();
-  }
-
-  @override
-  void dispose() {
-    SystemChrome.setPreferredOrientations([
-      DeviceOrientation.portraitDown,
-      DeviceOrientation.portraitUp,
-      DeviceOrientation.landscapeLeft,
-      DeviceOrientation.landscapeRight,
-    ]);
-    super.dispose();
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return Scaffold(
-      appBar: AppBar(
-        title: Row(
-          children: [
-            Expanded(child: Container()),
-            Text(title),
-            Expanded(child: Container()),
-            IconButton(
-              onPressed: () => setState(() {
-                currentCard = 0;
-              }),
-              icon: const Icon(Icons.repeat),
-            ),
-            ToggleButtons(
-                children: const [
-                  Icon(Icons.shuffle),
-                  Icon(Icons.translate),
-                ],
-                isSelected: _isSelected,
-                onPressed: (int index) {
-                  setState(() {
-                    _isSelected[index] = !_isSelected[index];
-                  });
-                })
-          ],
-        ),
-        centerTitle: true,
-      ),
-      body: _FlashcardPage(
-        card: widget.cards[currentCard],
-        index: currentCard,
-        languageFlipped: isLanguageSwitchedMode,
-        onNextCard: () {
-          setState(() {
-            currentCard = isShuffleMode ? randomCard : currentCard + 1;
-            if (currentCard == widget.cards.length) currentCard = 0;
-            title = encouragingWords[Random().nextInt(encouragingWords.length)];
-          });
-        },
-      ),
-    );
-  }
-}
-
-class _FlashcardPage extends StatefulWidget {
+class FlashcardPage extends StatefulWidget {
   final YokutangoEntry card;
   final Function() onNextCard;
   final bool languageFlipped;
   final int? index;
 
-  const _FlashcardPage({
+  const FlashcardPage({
     required this.card,
     required this.onNextCard,
     this.languageFlipped = false,
@@ -129,7 +21,7 @@ class _FlashcardPage extends StatefulWidget {
   _FlashcardPageState createState() => _FlashcardPageState();
 }
 
-class _FlashcardPageState extends State<_FlashcardPage> {
+class _FlashcardPageState extends State<FlashcardPage> {
   bool isPressed = false;
 
   @override