startRecording method

Future<void> startRecording(void onAudioData(Uint8List audioData))

Start recording audio from microphone

onAudioData Callback for audio data chunks (16kHz mono Int16 PCM)

Throws AudioCaptureError if recording cannot be started.

Implementation

Future<void> startRecording(
    void Function(Uint8List audioData) onAudioData) async {
  if (_isRecording) {
    _logger.warning('Already recording');
    return;
  }

  try {
    _onAudioData = onAudioData;

    // Check if we can record
    _logger.info('Checking microphone permission...');
    if (!await _recorder.hasPermission()) {
      _logger.error('No microphone permission');
      throw AudioCaptureError.permissionDenied();
    }
    _logger.info('✅ Microphone permission granted');

    // Start streaming audio in PCM 16-bit format
    _logger.info(
        'Starting audio stream: ${targetSampleRate}Hz, mono, PCM16bits...');
    final stream = await _recorder.startStream(
      const RecordConfig(
        encoder: AudioEncoder.pcm16bits,
        sampleRate: targetSampleRate,
        numChannels: 1, // Mono
        bitRate: 256000,
      ),
    );
    _logger.info('✅ Audio stream created, setting up listener...');

    // Track data delivery
    int chunkCount = 0;

    // Listen to audio stream
    _audioStreamSubscription = stream.listen(
      (data) {
        chunkCount++;
        // Log first few chunks to verify data flow
        if (chunkCount <= 3) {
          _logger.info(
              '🎵 Audio data received: chunk #$chunkCount, ${data.length} bytes');
        }
        if (_isRecording && _onAudioData != null) {
          _onAudioData!(data);
        } else {
          _logger.warning(
              '⚠️ Audio data ignored: isRecording=$_isRecording, hasCallback=${_onAudioData != null}');
        }
      },
      onError: (Object error) {
        _logger.error('❌ Audio stream error: $error');
      },
      onDone: () {
        _logger.info('🛑 Audio stream ended (total chunks: $chunkCount)');
      },
    );

    _isRecording = true;
    _recordingStateController.add(true);

    _logger.info(
        '✅ Recording started successfully (16kHz mono PCM) - waiting for audio data...');
  } catch (e) {
    _logger.error('❌ Failed to start recording: $e');
    _onAudioData = null;
    throw AudioCaptureError.engineStartFailed();
  }
}