Future<void> loadArpeggios() async {
  var arpeggiosFile = await loadMidi('arpeggios.mid');
  arpeggiosFile.tracks.forEach((track) {
    var isAudioTrack = false;
    var pattern = {};
    int time = 0;
    var trackName = 'name';

    track.forEach((event) {
      time += event.deltaTime;
      if (event is NoteOnEvent) {
        isAudioTrack = true;
        // 0 -> 0:0:0
        // 0.25 -> 0:0:1
        // 0.5 -> 0:0:2
        // 1 -> 0:1:0
        // 4 -> 1:0:0
        var quarters = (time / 480);
        var fullBars = ((quarters / 4).floor().toString());
        var fullQuarters = (quarters % 4).floor().toString();
        var fullSixteenth = ((quarters % 4 % 1) / 0.25).floor().toString();

        var str =
            '$fullBars:$fullQuarters:$fullSixteenth/${event.velocity.toString()}';
        if (!(pattern.containsKey(event.noteNumber))) {
          pattern[event.noteNumber] = [];
        }
        pattern[event.noteNumber].add(str);
      } else if (event is TrackNameEvent) {
        trackName = event.text;
      }
    });

    if (isAudioTrack) {
      arpeggioDict[trackName] = pattern;
      arpeggioTrackNameMap[trackName] = track;
    }
  });
}

var arpeggiosTrackNames = arpeggioDict.keys.toList();
var drumsTrackNames = drumsDict.keys.toList();

Future<MidiFile> loadMidi(String name) async {
  Directory tempDir = await getTemporaryDirectory();
  String tempPath = tempDir.path;
  File tempFile = File('$tempPath/$name');
  ByteData bd = await rootBundle.load('assets/$name');
  await tempFile.writeAsBytes(bd.buffer.asUint8List(), flush: true);
  return MidiParser().parseMidiFromFile(tempFile);
}

Future<List<int>> progressionToModiBuffer(List<Chord> chords, String arpeggioName,
    String drumPatternName, int bpm) async {
  List<MidiEvent> arpeggioTrack = [];

  var arpeggios = await loadMidi('arpeggios.mid');
  var arpeggio = arpeggios.tracks.firstWhere((track) {
    return track
        .any((event) => event is TrackNameEvent && event.text == arpeggioName);
  });
  chords.asMap().forEach((index, value) {
    arpeggio.forEach((f) {
      if (f is NoteOnEvent) {
        var newEvent = NoteOnEvent()
          ..deltaTime = f.deltaTime
          ..channel = 0
          ..velocity = f.velocity
          ..noteNumber = mapMidiToChord(f.noteNumber, value);
        arpeggioTrack.add(newEvent);
      } else if (f is NoteOffEvent) {
        var newEvent = NoteOffEvent()
          ..deltaTime = f.deltaTime
          ..channel = 0
          ..velocity = f.velocity
          ..noteNumber = mapMidiToChord(f.noteNumber, value);
        arpeggioTrack.add(newEvent);
      } else if (f is TrackNameEvent && index == 0) {
        arpeggioTrack.add(f);
      }
    });

  });
  arpeggioTrack.add(endOfTrackEvent);

  var tracks = [getDefaultMidiTempoTrack(bpm), arpeggioTrack];

  if (drumPatternName != "none") {
    List<MidiEvent> drumsTrack = [];
    var drums = await loadMidi('drums.mid');
    var drum = drums.tracks.firstWhere((track) {
      return track.any(
          (event) => event is TrackNameEvent && event.text == drumPatternName);
    });

    drum.forEach((f) {
      if (f is NoteOnEvent) {
        var newEvent = NoteOnEvent()
          ..deltaTime = f.deltaTime
          ..channel = 9 // Drums magic
          ..velocity = f.velocity
          ..noteNumber = f.noteNumber;
        drumsTrack.add(newEvent);
      } else if (f is NoteOffEvent) {
        var newEvent = NoteOffEvent()
          ..deltaTime = f.deltaTime
          ..channel = 9 // Drums magic
          ..velocity = f.velocity
          ..noteNumber = f.noteNumber;
        drumsTrack.add(newEvent);
      } else if (f is TrackNameEvent) {
        drumsTrack.add(f);
      }
    });

    drumsTrack.add(endOfTrackEvent);
    tracks.add(drumsTrack);
  }

  return MidiWriter().writeMidiToBuffer(MidiFile(tracks, defaultMidiHeader), running: true);
}