import 'package:flutter/material.dart';
import 'package:kana_kit/kana_kit.dart';
import '../models/custom_kanji_item.dart';
import '../services/custom_deck_repository.dart';

class AddCardScreen extends StatefulWidget {
  const AddCardScreen({super.key});

  @override
  State<AddCardScreen> createState() => _AddCardScreenState();
}

class _AddCardScreenState extends State<AddCardScreen> {
  final _formKey = GlobalKey<FormState>();
  final _japaneseController = TextEditingController();
  final _englishController = TextEditingController();
  final _kanjiController = TextEditingController();
  final _kanaKit = const KanaKit();
  final _deckRepository = CustomDeckRepository();
  bool _useInterval = false;
  late FocusNode _japaneseFocusNode;

  @override
  void initState() {
    super.initState();
    _japaneseController.addListener(_convertToKana);
    _japaneseFocusNode = FocusNode();
    _japaneseFocusNode.addListener(_onJapaneseFocusChange);
  }

  @override
  void dispose() {
    _japaneseController.removeListener(_convertToKana);
    _japaneseController.dispose();
    _englishController.dispose();
    _kanjiController.dispose();
    _japaneseFocusNode.removeListener(_onJapaneseFocusChange);
    _japaneseFocusNode.dispose();
    super.dispose();
  }

  void _convertToKana() {
    final text = _japaneseController.text;
    final selection = _japaneseController.selection;
    final offset = selection.baseOffset;

    if ((offset > 1 && text[offset - 1] == 'n' && text[offset - 2] != 'n') ||
        (offset == 1 && text[offset - 1] == 'n')) {
      return;
    }

    final converted = _kanaKit.toKana(text);

    if (converted != text) {
      _japaneseController.value = _japaneseController.value.copyWith(
        text: converted,
        selection: TextSelection.fromPosition(
          TextPosition(offset: converted.length),
        ),
      );
    }
  }

  void _onJapaneseFocusChange() {
    if (!_japaneseFocusNode.hasFocus) {
      _forceNConversion();
    }
  }

  void _forceNConversion() {
    final text = _japaneseController.text;
    if (text.isNotEmpty &&
        text.endsWith('n') &&
        _kanaKit.toKana(text) != text) {
      _japaneseController.text = _kanaKit.toKana(text);
    }
  }

  void _saveCard() {
    if (_formKey.currentState!.validate()) {
      final srsData = _useInterval
          ? SrsData(
              japaneseToEnglishNextReview: DateTime.now(),
              englishToJapaneseNextReview: DateTime.now(),
              listeningComprehensionNextReview: DateTime.now(),
            )
          : SrsData();

      final newItem = CustomKanjiItem(
        characters: _japaneseController.text,
        meaning: _englishController.text,
        kanji: _kanjiController.text.trim().isNotEmpty
            ? _kanjiController.text.trim()
            : null,
        useInterval: _useInterval,
        srsData: srsData,
      );
      _deckRepository.addCard(newItem);
      Navigator.of(context).pop();
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Add New Card')),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Form(
          key: _formKey,
          child: Column(
            children: [
              TextFormField(
                controller: _japaneseController,
                focusNode: _japaneseFocusNode,
                decoration: const InputDecoration(
                  labelText: 'Japanese (Kana)',
                  hintText: 'Enter Japanese vocabulary or kanji',
                ),
                validator: (value) {
                  if (value == null || value.isEmpty) {
                    return 'Please enter a Japanese term';
                  }
                  return null;
                },
              ),
              const SizedBox(height: 16),
              TextFormField(
                controller: _kanjiController,
                decoration: const InputDecoration(
                  labelText: 'Japanese (Kanji)',
                  hintText: 'Enter the kanji (optional)',
                ),
              ),
              const SizedBox(height: 16),
              TextFormField(
                controller: _englishController,
                decoration: const InputDecoration(
                  labelText: 'English',
                  hintText: 'Enter the English meaning',
                ),
                validator: (value) {
                  if (value == null || value.isEmpty) {
                    return 'Please enter an English meaning';
                  }
                  return null;
                },
              ),
              const SizedBox(height: 16),
              SwitchListTile(
                title: const Text('Use Interval-based SRS'),
                value: _useInterval,
                onChanged: (value) {
                  setState(() {
                    _useInterval = value;
                  });
                },
              ),
              const SizedBox(height: 32),
              ElevatedButton(
                onPressed: _saveCard,
                child: const Text('Save Card'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}