English/kouyu_english/lib/features/lesson/steps/speaking_step.dart

part of '../lesson_flow.dart';

class _SpeakingStep extends StatefulWidget {
  const _SpeakingStep({
    required this.state,
    required this.text,
    this.tip = '',
    required this.keepRecording,
    required this.onContinue,
  });
  final String text;
  final String tip;
  final AppState state;
  final bool keepRecording;
  final VoidCallback onContinue;

  @override
  State<_SpeakingStep> createState() => _SpeakingStepState();
}

class _SpeakingStepState extends State<_SpeakingStep>
    with VoiceAnswerMixin<_SpeakingStep> {
  String transcript = '';

  @override
  AppState get voiceState => widget.state;

  @override
  void dispose() {
    disposeVoiceAnswer(keepRecording: widget.keepRecording);
    super.dispose();
  }

  Future<void> _toggleMic() async {
    if (aiVoiceRecording) {
      await finishVoiceInput(
        noSpeech: '未识别到清晰发音，请重试或点击“播放示范音”。',
        onTranscript: (text) => transcript = text,
      );
      return;
    }

    await VoiceService.instance.stopRecordingPlayback();
    if (mounted) setState(() => playingRecording = false);
    if (!widget.keepRecording) {
      await VoiceService.instance.deleteRecording(recordingPath);
    }

    final recordStarted = await startVoiceInput();
    if (!recordStarted || !mounted) return;
    setState(() => recordingPath = null);
    showVoiceMessage('已启动麦克风录音，跟读完成后再次点击，AI 将自动转写发音。');
  }

  Future<void> _togglePlayRecording() async {
    if (playingRecording) {
      await VoiceService.instance.stopRecordingPlayback();
      if (mounted) setState(() => playingRecording = false);
      return;
    }
    if (recordingPath == null) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(const SnackBar(content: Text('请先使用麦克风跟读，录音完成后即可播放。')));
      return;
    }
    await playRecording();
  }

  @override
  Widget build(BuildContext context) => _LessonScaffold(
    step: 3,
    child: SpacedColumn(
      children: [
        const Eyebrow('跟读'),
        Text('先听，再说。', style: Theme.of(context).textTheme.headlineMedium),
        LexiconText(
          widget.text,
          state: widget.state,
          textAlign: TextAlign.center,
          style: const TextStyle(fontSize: 30, fontWeight: FontWeight.w600),
        ),
        SectionCard(
          tint: AppColors.surfaceMuted,
          child: _AudioRow(label: '播放示范音', speech: widget.text),
        ),
        if (widget.tip.isNotEmpty)
          SectionCard(
            tint: AppColors.warm,
            child: Text(
              widget.tip,
              style: TextStyle(color: AppColors.warmInk),
            ),
          ),
        SecondaryButton(
          label: transcribing
              ? '正在 AI 识别发音…'
              : (listening ? '停止录音并识别' : '使用麦克风跟读'),
          onPressed: transcribing ? null : _toggleMic,
        ),
        SecondaryButton(
          label: playingRecording ? '停止播放' : '播放跟读',
          onPressed: (listening || transcribing) ? null : _togglePlayRecording,
        ),
        if (recordingPath != null)
          SectionCard(
            tint: AppColors.softGreen,
            child: SpacedColumn(
              spacing: 8,
              children: [
                Text(widget.keepRecording ? '录音已保存在本机。' : '本次跟读录音仅在离开此步骤前保留。'),
                Row(
                  children: [
                    Expanded(
                      child: OutlinedButton.icon(
                        onPressed: (listening || transcribing)
                            ? null
                            : _togglePlayRecording,
                        icon: Icon(
                          playingRecording ? Icons.stop : Icons.play_arrow,
                        ),
                        label: Text(playingRecording ? '停止播放' : '播放跟读'),
                      ),
                    ),
                    const SizedBox(width: 8),
                    IconButton(
                      tooltip: '删除录音',
                      onPressed: (listening || transcribing)
                          ? null
                          : deleteRecording,
                      icon: const Icon(Icons.delete_outline),
                    ),
                  ],
                ),
              ],
            ),
          ),
        if (transcript.isNotEmpty)
          _SpokenComparisonCard(expected: widget.text, transcript: transcript),
        const SectionCard(
          child: Text(
            '转写只反映机器听成了什么，不等于发音评分；没听出的词可以再听示范、重说一次。这一步只算跟读练习，不作为独立口语证据。',
          ),
        ),
        PrimaryButton(
          label: transcript.isEmpty ? '我已跟读，继续' : '确认并继续',
          onPressed: widget.onContinue,
        ),
      ],
    ),
  );
}

class _SpokenComparisonCard extends StatelessWidget {
  const _SpokenComparisonCard({
    required this.expected,
    required this.transcript,
  });

  final String expected;
  final String transcript;

  @override
  Widget build(BuildContext context) {
    final result = compareSpoken(expected, transcript);
    final summary = result.matches
        ? '每个词都被听出来了。'
        : result.close
        ? '大部分词都被听出来了，橙色的词再练一次。'
        : '有几个词没被听出来：先听示范，再慢一点说。';
    return SectionCard(
      tint: result.close ? AppColors.softGreen : AppColors.warm,
      child: SpacedColumn(
        spacing: 8,
        children: [
          Text('听出 ${result.heardCount}/${result.total} 个词。$summary'),
          Wrap(
            spacing: 6,
            runSpacing: 6,
            children: [
              for (final word in result.words)
                Text(
                  word.text,
                  style: TextStyle(
                    fontSize: 18,
                    fontWeight: FontWeight.w600,
                    color: word.heard ? AppColors.green : AppColors.warmInk,
                    decoration: word.heard
                        ? TextDecoration.none
                        : TextDecoration.underline,
                  ),
                ),
            ],
          ),
          Text(
            '设备转写：$transcript',
            style: Theme.of(context).textTheme.bodySmall,
          ),
        ],
      ),
    );
  }
}