Chord Trainer

main.dart

import 'dart:math';

void main() {
  Chord chord = genChord();
  
  print(chordToRussian(chord));
}

Chord genChord() {
  final keyIdx = Random().nextInt(12);
  final key = Key.values[keyIdx];
  
  final type = CType.values[Random().nextInt(4)];
  
  return Chord(key, type: type);
}

final tooSimpleChords = <Chord>{
  const Chord(Key.C, ),
  const Chord(Key.D, type: CType.min),
  const Chord(Key.E, type: CType.min),
  const Chord(Key.F, ),
  const Chord(Key.G, ),
  const Chord(Key.A, type: CType.min),
  const Chord(Key.B, type: CType.dim),
};

class Chord {
  final Key key;
  final CType type;
  final Key bassKey;
  
  const Chord(this.key, {this.type = CType.maj, Key? bassKey}) 
    : this.bassKey = bassKey ?? key;
}

String chordToRussian(Chord ch) {
  String res = switch(ch.key) {
    Key.A => 'Ля',
    Key.Ab => 'Ля бемоль',
    Key.B => 'Си',
    Key.Bb => 'Си бемоль',
    Key.C => 'До',
    Key.D => 'Ре',
    Key.Db => 'Ре бемоль',
    Key.E => 'Ми',
    Key.Eb => 'Ми бемоль',
    Key.F => 'Фа',
    Key.G => 'Соль',
    Key.Gb => 'Соль бемоль',
  };
  
  if (ch.type != CType.maj) {
    res += switch(ch.type) {
      CType.maj => ' Мажор',
      CType.min => ' Минор',
      CType.dim => ' Уменьшенный',
      CType.aug => ' Увеличенный',
    };
  }
  
  return res;
}

enum CType {
  maj, min, dim, aug,
}

enum Key {
  Ab, A, 
  Bb, B, 
  C, 
  Db, D, 
  Eb, E, 
  F, 
  Gb, G, 
}