trying to translate c++ codes to dart from here http://gameprogrammingpatterns.com/command.html#configuring-input

command.dart

// trying to translate c++ codes to dart
// http://gameprogrammingpatterns.com/command.html#configuring-input

void main() {
  print("Starting game\n");

  JumpCommand jumpCommand = JumpCommand();
  FireCommand fireCommand = FireCommand();
  WalkCommand walkCommand = WalkCommand();
  BlockCommand blockCommand = BlockCommand();
  
  InputHandler inputHandler = InputHandler(
    buttonX: jumpCommand,
    buttonY: fireCommand,
    buttonA: walkCommand,
    buttonB: blockCommand,
  );

  print("Press button A");
  inputHandler.pressed = Button.BUTTON_A;
  inputHandler.handleInput();

  print("Press button X");
  inputHandler.pressed = Button.BUTTON_X;
  inputHandler.handleInput();

  print("Press button Y");
  inputHandler.pressed = Button.BUTTON_Y;
  inputHandler.handleInput();
}

abstract class Command {
  void execute();
}

class JumpCommand extends Command {
  void execute() {
    print("Lets jump!\n");
  }
}

class FireCommand extends Command {
  void execute() {
    print("Fire!!!\n");
  }
}

class WalkCommand extends Command {
  void execute() {
    print("Walking\n");
  }
}

class BlockCommand extends Command {
  void execute() {
    print("Blocking...\n");
  }
}

enum Button {
  BUTTON_X,
  BUTTON_Y,
  BUTTON_A,
  BUTTON_B,
  NULL,
}

class InputHandler {
  Command buttonX;
  Command buttonY;
  Command buttonA;
  Command buttonB;
  Button pressed;

  InputHandler({
    this.buttonX,
    this.buttonY,
    this.buttonA,
    this.buttonB,
  });

  void handleInput() {
    if (isPressed(Button.BUTTON_X)) return buttonX.execute();
    if (isPressed(Button.BUTTON_Y)) return buttonY.execute();
    if (isPressed(Button.BUTTON_A)) return buttonA.execute();
    if (isPressed(Button.BUTTON_B)) return buttonB.execute();

    // Nothing pressed, so do nothing.
    return null;
  }

  bool isPressed(Button button) {
    return button == pressed ? true : false;
  }
}