MysteryGame - Completed with State Pattern

main.dart

import 'dart:io';

abstract class GameState {
  String getPrompt();
  void process(String input, MysteryGame game);
}

//#region Concrete states
class TheKitchenGameState extends GameState {

  static const List<String> KITCHEN_ACTION_LIST = [
    'chop',
    'chop',
    'chop',
    'chop',
    'chop',
    'fry',
    'serve',
  ];

  int completedKitchenActionIndex = 0;

  @override
  String getPrompt() {
    if (completedKitchenActionIndex == 0) {
      return 'Welcome to The Kitchen. Do your actions without mistake!';
    }
  }

  @override
  void process(String input, MysteryGame game) {
    if (input == KITCHEN_ACTION_LIST[completedKitchenActionIndex]) {
      completedKitchenActionIndex++;
      if (completedKitchenActionIndex == KITCHEN_ACTION_LIST.length) {
        game.state = DanceStudioGameState();
      }
    } else {
      game.state = DeadGameState();
    }
  }
}

class DanceStudioGameState extends GameState {
  static const List<String> DANCE_ACTIONS = [
    'left',
    'right',
    'jump',
    'jump',
  ];

  int completedDanceActionIndex = 0;

  @override
  String getPrompt() {
    if (completedDanceActionIndex == 0) {
      return 'Welcome to the Dance Studio! Do the secret dance to pass.';
    }
    return null;
  }

  @override
  void process(String input, MysteryGame game) {
    if (input == DANCE_ACTIONS[completedDanceActionIndex]) {
      completedDanceActionIndex++;
      if (completedDanceActionIndex == DANCE_ACTIONS.length) {
        game.state = MusicStudioGameState();
      }
    } else {
      game.state = DeadGameState();
    }
  }

}

class MusicStudioGameState extends GameState {
  DateTime lastInputTime;
  int baseIntervalMs;

  static const List<String> NOTES = [
    'c', 'c', 'd', 'c', 'f', 'e'
  ];
  int completedNoteIndex = 0;
  int retriesAllowed = 3;

  @override
  String getPrompt() {
    if (completedNoteIndex == 0) {
      return "Sing happy birthday in C! (pretend all notes are quarter notes)";
    }
    return null;
  }

  @override
  void process(String input, MysteryGame game) {
    if (input == NOTES[completedNoteIndex]) {
      if (_isTempoAcceptable()) {
        completedNoteIndex++;
        lastInputTime = DateTime.now();
        if (completedNoteIndex == NOTES.length) {
          game.state = SuccessGameState();
        }
      } else {
        print('Wrong tempo!');
        _reset();
      }
    } else {
      if (retriesAllowed == 0) {
        game.state = DeadGameState();
      } else {
        _reset();
      }
    }
  }

  void _reset() {
    retriesAllowed--;
    completedNoteIndex = 0;
    baseIntervalMs = null;
    lastInputTime = null;
  }

  bool _isTempoAcceptable() {
    if (lastInputTime == null) {
      // no need to check first note
      return true;
    }
    DateTime now = DateTime.now();
    int intervalInMs = now.millisecondsSinceEpoch - lastInputTime.millisecondsSinceEpoch;
    if (baseIntervalMs == null) {
      // set base tempo on second note
      baseIntervalMs = intervalInMs;


      print("(Base tempo = ${60 / intervalInMs * 1000})");
      return true;
    }
    return baseIntervalMs * 0.75 < intervalInMs && intervalInMs < baseIntervalMs * 1.25;
  }
  
}

class StartGameState extends GameState {
  @override
  String getPrompt() {
    return 'Type ready to start the game';
  }

  @override
  void process(String input, MysteryGame game) {
    if (input == 'ready') {
      game.state = TheKitchenGameState();
    }
  }

}

class SuccessGameState extends GameState {
  @override
  String getPrompt() {
    return 'Congratulations! You are successful 🎉';
  }

  @override
  void process(String input, MysteryGame game) {
    if (input == 'RIP') {
      game.state = DeadGameState();
    }
  }
}


class DeadGameState extends GameState {
  @override
  String getPrompt() {
    return 'You are dead. Like this game? Feel free to retry.';
  }

  @override
  void process(String input, MysteryGame game) {
    if (input == 'retry') {
      game.state = StartGameState();
    }
  }

}

//#endregion

class MysteryGame {
  GameState state;

  MysteryGame() {
    state = StartGameState();
  }

  String getPrompt() {
    return state.getPrompt();
  }

  void process(String input) {
    return state.process(input, this);
  }
}


void main() {
  print('MysteryMaze v1.0');
  print('---');
  MysteryGame game = MysteryGame();
  while (true) {
    if (game.getPrompt() != null) {
      print(game.getPrompt());
    }
    String input = stdin.readLineSync();
    if (input == 'exit') {
      break;
    } else {
      game.process(input);
    }
  }
  print('Good bye! Come MysteryMaze again soon!');
}