option_set_example.dart

class Option {
  final int rawValue;

  Option(this.rawValue);

  Option.fromSet(Set<Option> set) : rawValue = set.rawValue;

  Option.fromList(List<Option> set) : rawValue = set.rawValue;

  Option operator |(Option option) {
    return Option(rawValue | option.rawValue);
  }

  Option operator &(Option option) {
    return Option(rawValue & option.rawValue);
  }

  Option operator ^(Option option) {
    return Option(rawValue ^ option.rawValue);
  }

  Option operator ~() {
    return Option(~rawValue);
  }

  bool has(Option option) {
    return (rawValue & option.rawValue) == option.rawValue;
  }

  Option added(Option option) {
    return Option(rawValue | option.rawValue);
  }

  Option dropped(Option option) {
    return Option(rawValue ^ option.rawValue);
  }

  int get count {
    int value = rawValue;
    int count = 0;
    while (value != 0) {
      if (value & 1 == 1) {
        count += 1;
      }
      value >>= 1;
    }
    return count;
  }

  @override
  bool operator ==(Object other) {
    return hashCode == other.hashCode;
  }

  @override
  int get hashCode => rawValue;

  @override
  String toString() {
    return 'rawValue: $rawValue,\tbitmask: ${rawValue.toRadixString(2).padLeft(8, '0')}';
  }
}

extension SetOptions on Set<Option> {
  int get rawValue {
    int result = 0;
    forEach((element) {
      result |= element.rawValue;
    });
    return result;
  }
}

extension ListOptions on List<Option> {
  int get rawValue {
    return toSet().rawValue;
  }
}

class LanguageOption extends Option {
  static final java = LanguageOption(1 << 0);
  static final swift = LanguageOption(1 << 1);
  static final dart = LanguageOption(1 << 2);
  static final cpp = LanguageOption(1 << 3);
  static final c = LanguageOption(1 << 4);
  static final go = LanguageOption(1 << 5);

  static final allOptions = [
    LanguageOption.java,
    LanguageOption.swift,
    LanguageOption.dart,
    LanguageOption.cpp,
    LanguageOption.c,
    LanguageOption.go,
  ];

  // Ущербное наследование
  LanguageOption(int rawValue) : super(rawValue);
}

main() {
  print('languages:');
  for (LanguageOption option in LanguageOption.allOptions) {
    print(option);
  }
  print('-');
  
  final vacancyLanguagesOption = LanguageOption([
    LanguageOption.c,
    LanguageOption.dart,
    LanguageOption.java,
    LanguageOption.go,
  ].rawValue);
  final candidateLanguageOption = LanguageOption([
    LanguageOption.c,
    LanguageOption.dart,
    LanguageOption.swift,
  ].rawValue);
  print('vacancy languages raw value:');
  print(vacancyLanguagesOption);
  print('candidate languages raw value:');
  print(candidateLanguageOption);
  print('-');
  
  final intersectionOption = vacancyLanguagesOption & candidateLanguageOption;
  print('languages intersection raw value:');
  print(intersectionOption);
  print('-');
  
  print('Intersection languages:');
  for (LanguageOption option in LanguageOption.allOptions) {
    if (intersectionOption.has(option)) {
      print(option);
    }
  }
  print('-');
  
  print('Hardcode check:');
  print(intersectionOption.has(LanguageOption.dart));
  print(intersectionOption.has(LanguageOption.c));
}