Jokenpo system

home.dart

import 'package:flutter/material.dart';
import 'jokenpo.dart';
import 'jokenpoTypes.dart';

class Homepage extends StatefulWidget {
  Homepage({Key key, title: 'Home'}) : super(key: key);

  @override
  _HomepageState createState() => _HomepageState();
}

class _HomepageState extends State<Homepage> {
  var _appOption = '-';
  var _message = '';
  var _totalWins = 0;
  var _winsInARoll = 0;

  void play(JokenpoTypes option) {
    var result = Jokenpo.play(option);
    var appOption = result['appOption'];
    var optionAsMessage = 'Tesoura';

    switch (appOption) {
      case JokenpoTypes.STONE:
        optionAsMessage = 'Pedra';
        break;
      case JokenpoTypes.PAPER:
        optionAsMessage = 'Papel';
        break;
      default:
        break;
    }

    var resultMessage = result['message'];

    setState(() {
      _appOption = optionAsMessage;
      _message = resultMessage;

      if (resultMessage.toString().contains("ganhou")) {
        ++_totalWins;
        ++_winsInARoll;

        // show custom message
        if (_winsInARoll >= 2) {
          _message = _message + '\nJá é a $_winsInARollª vitória seguida';
        }

        if (_winsInARoll >= 4) {
          _message =
              _message + '\nVitória desenfreada!!!! Aposta na megasena logo!';
        }
      } else {
        _winsInARoll = 0;
      }
    });
  }

  AppBar appBarBuilder() {
    return AppBar(
      title: Text('Vitórias $_totalWins'),
    );
  }

  Widget jokenpo() {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.center,
      children: <Widget>[
        Padding(
            padding: EdgeInsets.only(top: 16, bottom: 16),
            child: Text(
              'Escolha do aplicativo',
              textAlign: TextAlign.center,
              style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
            )),
        Text(_appOption),
        Expanded(
            child: Center(
          child: Text(
            _message,
            style: TextStyle(fontSize: 15, fontWeight: FontWeight.w700),
          ),
        )),
        Text(
          'Escolha do jogador',
          textAlign: TextAlign.center,
          style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
        ),
        Padding(
          padding: EdgeInsets.only(top: 16, bottom: 16),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: <Widget>[
              GestureDetector(
                onTap: () => play(JokenpoTypes.STONE),
                child: Text('Pedra'),
              ),
              GestureDetector(
                onTap: () => play(JokenpoTypes.PAPER),
                child: Text('Papel'),
              ),
              GestureDetector(
                onTap: () => play(JokenpoTypes.SCISSORS),
                child: Text('Tesoura'),
              ),
            ],
          ),
        )
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: appBarBuilder(),
      body: jokenpo(),
    );
  }
}

jokenpo.dart

import 'dart:math';
import 'package:eai_flutter_class/jokenpoTypes.dart';

import 'jokenpoTypes.dart';

class Jokenpo {
  static String calc(JokenpoTypes option, JokenpoTypes appOption) {    
    if ((option == JokenpoTypes.STONE && appOption == JokenpoTypes.SCISSORS) ||
        (option == JokenpoTypes.SCISSORS && appOption == JokenpoTypes.PAPER) ||
        (option == JokenpoTypes.PAPER && appOption == JokenpoTypes.STONE)) {
      return 'Parabéns, você ganhou!';
    }

    if ((appOption == JokenpoTypes.STONE && option == JokenpoTypes.SCISSORS) ||
        (appOption == JokenpoTypes.SCISSORS && option == JokenpoTypes.PAPER) ||
        (appOption == JokenpoTypes.PAPER && option == JokenpoTypes.STONE)) {
      return 'Você perdeu, tente novamente!';
    }

    return 'Empate';
  }

  static Map<String, dynamic> play(JokenpoTypes option) {
    var result = new Map<String, dynamic>();
    var appOption =
        JokenpoTypes.values[Random().nextInt(JokenpoTypes.values.length)];

    result['appOption'] = appOption;
    result['message'] = calc(option, appOption);

    return result;
  }
}

jokenpoTypes.dart

enum JokenpoTypes { STONE, PAPER, SCISSORS }

main.dart

import 'package:flutter/material.dart';
import 'home.dart';

const appName = "Aula Flutter";
void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: appName,
      darkTheme: ThemeData.dark().copyWith(primaryColor: Colors.green),
      theme: ThemeData(
        primarySwatch: Colors.red,
      ),
      home: Homepage(),
      debugShowCheckedModeBanner: false,
    );
  }
}