import 'dart:async';

import 'package:flutter/material.dart';

import '../models/incoming_question.dart';
import '../services/questions_api_service.dart';
import '../services/spelling_text_to_speech.dart';
import '../theme/app_theme.dart';
import '../utils/spelling_spoken_word.dart';

/// Spelling quiz: hear the word, type your spelling, and submit.
class SpellingQuestionTile extends StatefulWidget {
  const SpellingQuestionTile({
    super.key,
    required this.questionId,
    required this.questionText,
    required this.onSubmitAnswer,
    required this.onDefer,
    this.busy = false,
    this.spokenWord,
    this.audioTitle,
    this.needsPrepare = false,
    this.onPrepared,
    this.prepareQuestion,
  });

  final String questionId;
  final String questionText;
  final Future<void> Function(String answerText) onSubmitAnswer;
  final Future<void> Function() onDefer;
  final bool busy;

  /// Word read aloud; filled by [prepareQuestion] when omitted.
  final String? spokenWord;

  /// Question id used as the TTS utterance title.
  final String? audioTitle;

  /// When true, calls the prepare API to select a word at tile load.
  final bool needsPrepare;

  /// Called when prepare returns an updated question payload.
  final ValueChanged<IncomingQuestion>? onPrepared;

  /// Visible for widget tests (defaults to API prepare).
  final Future<IncomingQuestion?> Function(String questionId)? prepareQuestion;

  @override
  State<SpellingQuestionTile> createState() => _SpellingQuestionTileState();
}

class _SpellingQuestionTileState extends State<SpellingQuestionTile> {
  final SpellingTextToSpeech _speech = SpellingTextToSpeech();
  final QuestionsApiService _api = QuestionsApiService();
  final TextEditingController _answerController = TextEditingController();

  String? _spokenWord;
  String? _audioTitle;
  bool _preparing = false;

  @override
  void initState() {
    super.initState();
    _spokenWord = widget.spokenWord;
    _audioTitle = widget.audioTitle ?? widget.questionId;
    WidgetsBinding.instance.addPostFrameCallback((_) => unawaited(_prepareAndSpeak()));
  }

  @override
  void didUpdateWidget(SpellingQuestionTile oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.questionId != widget.questionId) {
      _answerController.clear();
      _spokenWord = widget.spokenWord;
      _audioTitle = widget.audioTitle ?? widget.questionId;
      WidgetsBinding.instance.addPostFrameCallback((_) => unawaited(_prepareAndSpeak()));
    }
  }

  @override
  void dispose() {
    _answerController.dispose();
    unawaited(_speech.stop());
    super.dispose();
  }

  Future<void> _prepareAndSpeak() async {
    if (_preparing) {
      return;
    }

    if (!widget.needsPrepare) {
      await _speakWord();
      return;
    }

    _preparing = true;
    setState(() {});
    try {
      final IncomingQuestion? prepared = widget.prepareQuestion != null
          ? await widget.prepareQuestion!(widget.questionId)
          : await _api.prepareSpellingQuestion(questionId: widget.questionId);
      if (!mounted) {
        return;
      }
      if (prepared != null) {
        setState(() {
          _spokenWord = prepared.spokenWord ?? _spokenWord;
          _audioTitle = prepared.audioTitle ?? prepared.id;
        });
        widget.onPrepared?.call(prepared);
      }
      await _speakWord();
    } finally {
      if (mounted) {
        setState(() => _preparing = false);
      }
    }
  }

  String? get _wordToSpeak =>
      _spokenWord ?? spellingWordToSpeak(widget.questionText);

  bool get _wordReady {
    final String? word = _wordToSpeak;
    return word != null && word.isNotEmpty;
  }

  Future<void> _speakWord() async {
    final String? word = _wordToSpeak;
    if (word == null || word.isEmpty) {
      return;
    }
    await _speech.speak(
      word,
      title: _audioTitle ?? widget.questionId,
    );
  }

  Future<void> _submitAnswer() async {
    final String answer = _answerController.text.trim();
    if (answer.isEmpty || widget.busy || _preparing || !_wordReady) {
      return;
    }
    await widget.onSubmitAnswer(answer);
  }

  @override
  Widget build(BuildContext context) {
    final bool canInteract = _wordReady && !widget.busy && !_preparing;
    final bool canSpeak = _wordReady;

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: <Widget>[
          if (_preparing)
            const Padding(
              padding: EdgeInsets.only(bottom: 24),
              child: Center(
                child: SizedBox(
                  width: 28,
                  height: 28,
                  child: CircularProgressIndicator(strokeWidth: 2),
                ),
              ),
            ),
          Center(
            child: IconButton.filled(
              key: const Key('spelling-speak-word'),
              onPressed: canSpeak && !widget.busy
                  ? () => unawaited(_speakWord())
                  : null,
              tooltip: 'Hear the word',
              iconSize: 36,
              style: IconButton.styleFrom(
                backgroundColor: AppColors.surfaceElevated,
                foregroundColor: canSpeak ? AppColors.accent : AppColors.textSecondary,
                disabledForegroundColor: AppColors.textSecondary,
                minimumSize: const Size(72, 72),
              ),
              icon: const Icon(Icons.volume_up_rounded),
            ),
          ),
          const SizedBox(height: 28),
          TextField(
            key: const Key('spelling-answer-field'),
            controller: _answerController,
            enabled: canInteract,
            textCapitalization: TextCapitalization.none,
            autocorrect: false,
            enableSuggestions: false,
            style: Theme.of(context).textTheme.titleLarge?.copyWith(
                  color: AppColors.textPrimary,
                ),
            decoration: InputDecoration(
              hintText: canInteract ? 'Type the spelling' : 'Loading word…',
              hintStyle: const TextStyle(color: AppColors.textSecondary),
              filled: true,
              fillColor: AppColors.surfaceElevated,
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(12),
                borderSide: BorderSide.none,
              ),
              contentPadding: const EdgeInsets.symmetric(
                horizontal: 16,
                vertical: 14,
              ),
            ),
            onSubmitted: canInteract ? (_) => unawaited(_submitAnswer()) : null,
          ),
          const SizedBox(height: 16),
          FilledButton(
            key: const Key('spelling-submit-answer'),
            onPressed: canInteract ? () => unawaited(_submitAnswer()) : null,
            child: const Text('Submit'),
          ),
          const SizedBox(height: 8),
          TextButton(
            key: const Key('spelling-skip-question'),
            onPressed: widget.busy || _preparing ? null : widget.onDefer,
            child: const Text('Skip for now'),
          ),
        ],
      ),
    );
  }
}