import 'dart:async';
import 'dart:html';
import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'package:just_audio/just_audio.dart';

class _Recorder {
  MediaRecorder? _mediaRecorder;
  List<Blob>? _audioBlobParts;
  String? _recordingUrl;

  Future<void> init() async {
    assert(_mediaRecorder == null);

    final stream =
        await window.navigator.mediaDevices?.getUserMedia({'audio': true});
    if (stream == null) return;
    _mediaRecorder = MediaRecorder(stream);

    _audioBlobParts = [];
    _mediaRecorder!.addEventListener('dataavailable', _onDataAvailable);
  }

  void _onDataAvailable(Event event) {
    final blobEvent = event as BlobEvent;
    _audioBlobParts!.add(blobEvent.data!);
  }

  Future<void> start() async {
    assert(_mediaRecorder != null);

    _mediaRecorder!.start();
  }

  /// Stops the recorder and returns an URL pointing to the recording.
  Future<String> stop() async {
    assert(_mediaRecorder != null);
    assert(_recordingUrl == null);

    final completer = Completer<String>();

    void onStop(_) {
      assert(_audioBlobParts != null);

      final blob = Blob(_audioBlobParts!);
      _audioBlobParts = null;

      completer.complete(Url.createObjectUrl(blob));
    }

    _mediaRecorder!.addEventListener('stop', onStop);
    _mediaRecorder!.stop();
    _recordingUrl = await completer.future;
    _mediaRecorder!.removeEventListener('stop', onStop);

    return _recordingUrl!;
  }

  Future<Uint8List> toBytes() async {
    assert(_recordingUrl != null);

    final result = await http.get(Uri.parse(_recordingUrl!));
    return result.bodyBytes;
  }

  void dispose() {
    assert(_mediaRecorder != null);

    _mediaRecorder!.removeEventListener('dataavailable', _onDataAvailable);
    _mediaRecorder = null;
  }
}

void main() {
  runApp(const MicrophoneExampleApp());
}

class MicrophoneExampleApp extends StatefulWidget {
  /// Constructs [MicrophoneExampleApp].
  const MicrophoneExampleApp({super.key});

  @override
  State<MicrophoneExampleApp> createState() => _MicrophoneExampleAppState();
}

class _MicrophoneExampleAppState extends State<MicrophoneExampleApp> {
  _Recorder? _recorder;
  AudioPlayer? _audioPlayer;

  @override
  void dispose() {
    _recorder?.dispose();
    _audioPlayer?.dispose();
    super.dispose();
  }

  Future<void> _initRecorder() async {
    _recorder?.dispose();
    await window.navigator.permissions?.query({'name': 'microphone'});
    _recorder = _Recorder();
    await _recorder!.init();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: Column(
            children: [
              OutlinedButton(
                onPressed: _initRecorder,
                child: const Text('Restart recorder'),
              ),
              OutlinedButton(
                onPressed: () {
                  _recorder?.start();
                },
                child: const Text('Start recording'),
              ),
              OutlinedButton(
                onPressed: () async {
                  await _recorder?.stop();
                },
                child: const Text('Stop recording'),
              ),
              OutlinedButton(
                onPressed: () async {
                  final bytes = await _recorder?.toBytes();
                  print(bytes);
                },
                child: const Text('To Butes'),
              ),
              OutlinedButton(
                onPressed: () async {
                  _audioPlayer?.dispose();
                  _audioPlayer = AudioPlayer();
                  await _audioPlayer!.setUrl(_recorder!._recordingUrl!);
                  await _audioPlayer!.play();
                },
                child: const Text('Play recording'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}