Add minimal gameplay

lib/move_finder.dart

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+
+import 'game_board.dart';
+import 'game_board_scorer.dart';
+
+class MoveSearchArgs {
+  MoveSearchArgs(
+      {required this.board, required this.player, required this.numPlies});
+
+  final GameBoard board;
+  final PieceType player;
+  final int numPlies;
+}
+
+/// A move and its score. Used by the minimax algorithm.
+class ScoredMove {
+  final int score;
+  final Position move;
+
+  const ScoredMove(this.score, this.move);
+}
+
+// The [compute] function requires a top-level method as its first argument.
+// This is that method for [MoveFinder].
+Position? _findNextMove(MoveSearchArgs args) {
+  final bestMove = _performSearchPly(
+      args.board, args.player, args.player, args.numPlies - 1);
+  return bestMove?.move;
+}
+
+// This is a recursive implementation of minimax, an algorithm so old it has
+// its own Wikipedia page: https://wikipedia.org/wiki/Minimax.
+ScoredMove? _performSearchPly(
+  GameBoard board,
+  PieceType scoringPlayer,
+  PieceType player,
+  int pliesRemaining,
+) {
+  final availableMoves = board.getMovesForPlayer(player);
+
+  if (availableMoves.isEmpty) {
+    return null;
+  }
+
+  var score = (scoringPlayer == player)
+      ? GameBoardScorer.minScore
+      : GameBoardScorer.maxScore;
+  ScoredMove? bestMove;
+
+  for (var i = 0; i < availableMoves.length; i++) {
+    final newBoard =
+        board.updateForMove(availableMoves[i].x, availableMoves[i].y, player);
+    if (pliesRemaining > 0 &&
+        newBoard.getMovesForPlayer(getOpponent(player)).isNotEmpty) {
+      // Opponent has next turn.
+      score = _performSearchPly(
+            newBoard,
+            scoringPlayer,
+            getOpponent(player),
+            pliesRemaining - 1,
+          )?.score ??
+          0;
+    } else if (pliesRemaining > 0 &&
+        newBoard.getMovesForPlayer(player).isNotEmpty) {
+      // Opponent has no moves; player gets another turn.
+      score = _performSearchPly(
+            newBoard,
+            scoringPlayer,
+            player,
+            pliesRemaining - 1,
+          )?.score ??
+          0;
+    } else {
+      // Game is over or the search has reached maximum depth.
+      score = GameBoardScorer(newBoard).getScore(scoringPlayer);
+    }
+
+    if (bestMove == null ||
+        (score > bestMove.score && scoringPlayer == player) ||
+        (score < bestMove.score && scoringPlayer != player)) {
+      bestMove =
+          ScoredMove(score, Position(availableMoves[i].x, availableMoves[i].y));
+    }
+  }
+
+  return bestMove;
+}
+
+/// The [MoveFinder] class exists to provide its [findNextMove] method, which
+/// uses the minimax algorithm to look for the best available move on
+/// [initialBoard] a [GameBoardScorer] to provide the heuristic.
+class MoveFinder {
+  final GameBoard initialBoard;
+
+  MoveFinder(this.initialBoard);
+
+  /// Searches the tree of possible moves on [initialBoard] to a depth of
+  /// [numPlies], looking for the best possible move for [player]. Because the
+  /// actual work is done in an isolate, a [Future] is used as the return value.
+  Future<Position?> findNextMove(PieceType player, int numPlies) {
+    return compute(
+      _findNextMove,
+      MoveSearchArgs(
+        board: initialBoard,
+        player: player,
+        numPlies: numPlies,
+      ),
+    );
+  }
+}

lib/provider/data.dart

-import 'package:flutter/foundation.dart';
-
-class Data extends ChangeNotifier {
-
-  // Configuration available values
-  List _availableDifficultyLevels = ['easy', 'medium', 'hard'];
-
-  List get availableDifficultyLevels => _availableDifficultyLevels;
-
-  // Application default configuration
-  String _level = 'medium';
-  String _size = '8x8';
-  String _skin = 'default';
-
-  // Game data
-  bool _gameRunning = false;
-  int _sizeVertical = null;
-  int _sizeHorizontal = null;
-  List _cells = [];
-
-  String get level => _level;
-  void updateLevel(String level) {
-    _level = level;
-    notifyListeners();
-  }
-
-  String get size => _size;
-  int get sizeVertical => _sizeVertical;
-  int get sizeHorizontal => _sizeHorizontal;
-  void updateSize(String size) {
-    _size = size;
-    _sizeHorizontal = int.parse(_size.split('x')[0]);
-    _sizeVertical = int.parse(_size.split('x')[1]);
-    notifyListeners();
-  }
-
-  String get skin => _skin;
-  void updateSkin(String skin) {
-    _skin = skin;
-    notifyListeners();
-  }
-
-  getParameterValue(String parameterCode) {
-    switch(parameterCode) {
-      case 'difficulty': { return _level; }
-      break;
-    }
-  }
-
-  List getParameterAvailableValues(String parameterCode) {
-    switch(parameterCode) {
-      case 'difficulty': { return _availableDifficultyLevels; }
-      break;
-    }
-  }
-
-  setParameterValue(String parameterCode, String parameterValue) {
-    switch(parameterCode) {
-      case 'difficulty': { updateLevel(parameterValue); }
-      break;
-    }
-  }
-
-  List get cells => _cells;
-  void updateCells(List cells) {
-    _cells = cells;
-    notifyListeners();
-  }
-
-  bool get gameRunning => _gameRunning;
-  void updateGameRunning(bool gameRunning) {
-    _gameRunning = gameRunning;
-    notifyListeners();
-  }
-}

lib/screens/home.dart

-import 'package:flutter/material.dart';
-import 'package:provider/provider.dart';
-
-import '../provider/data.dart';
-
-class Home extends StatelessWidget {
-  static const String id = 'home';
-
-  @override
-  Widget build(BuildContext context) {
-    Data myProvider = Provider.of<Data>(context);
-
-    return Scaffold(
-      appBar: AppBar(
-        title: new Text('Reversi'),
-
-        actions: [
-        ],
-        
-        leading: IconButton(
-          icon: Image.asset('assets/icons/application.png'),
-          onPressed: () { },
-        ),
-      ),
-      body: SafeArea(
-        child: Center(
-          child: Text('🎮')
-        ),
-      )
-    );
-  }
-}

lib/styling.dart

+import 'package:flutter/widgets.dart';
+
+import 'game_board.dart';
+
+abstract class Styling {
+  // **** GRADIENTS AND COLORS ****
+
+  static const Map<PieceType, String> assetImageCodes = {
+    PieceType.black: 'black',
+    PieceType.white: 'white',
+    PieceType.empty: 'empty',
+  };
+
+  static const BorderSide boardCellBorderSide = BorderSide(
+    color: Color(0xff108010),
+    width: 1.0,
+  );
+
+  static const BoxDecoration boardCellDecoration = BoxDecoration(
+    color: Color(0xff50bb50),
+    border: Border(
+      bottom: boardCellBorderSide,
+      top: boardCellBorderSide,
+      left: boardCellBorderSide,
+      right: boardCellBorderSide,
+    ),
+  );
+
+  static const BoxDecoration mainWidgetDecoration = BoxDecoration(
+    color: Color(0xffffffff)
+  );
+
+  static const thinkingColor = Color(0xff2196f3);
+
+  // **** ANIMATIONS ****
+
+  static const Duration thinkingFadeDuration = Duration(milliseconds: 500);
+
+  static const pieceFlipDuration = Duration(milliseconds: 300);
+
+  // **** SIZES ****
+
+  static const thinkingSize = 10.0;
+
+  // **** BOXES ****
+
+  static const BorderSide activePlayerIndicatorBorder = BorderSide(
+    color: Color(0xff2196f3),
+    width: 10.0,
+  );
+
+  static const BorderSide inactivePlayerIndicatorBorder = BorderSide(
+    color: Color(0x00000000),
+    width: 10.0,
+  );
+
+  static const activePlayerIndicator = BoxDecoration(
+    borderRadius: const BorderRadius.all(const Radius.circular(10.0)),
+    border: Border(
+      bottom: activePlayerIndicatorBorder,
+      top: activePlayerIndicatorBorder,
+      left: activePlayerIndicatorBorder,
+      right: activePlayerIndicatorBorder,
+    ),
+  );
+
+  static const inactivePlayerIndicator = BoxDecoration(
+    borderRadius: const BorderRadius.all(const Radius.circular(10.0)),
+    border: Border(
+      bottom: inactivePlayerIndicatorBorder,
+      top: inactivePlayerIndicatorBorder,
+      left: inactivePlayerIndicatorBorder,
+      right: inactivePlayerIndicatorBorder,
+    ),
+  );
+}

lib/thinking_indicator.dart

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/widgets.dart';
+import 'styling.dart';
+
+/// This is a self-animated progress spinner, only instead of spinning it
+/// moves five little circles in a horizontal arrangement.
+class ThinkingIndicator extends ImplicitlyAnimatedWidget {
+  final Color color;
+  final double height;
+  final bool visible;
+
+  ThinkingIndicator({
+    this.color = const Color(0xffffffff),
+    this.height = 10.0,
+    this.visible = true,
+    Key? key,
+  }) : super(
+          duration: Styling.thinkingFadeDuration,
+          key: key,
+        );
+
+  @override
+  ImplicitlyAnimatedWidgetState createState() => _ThinkingIndicatorState();
+}
+
+class _ThinkingIndicatorState
+    extends AnimatedWidgetBaseState<ThinkingIndicator> {
+  Tween<double>? _opacityTween;
+
+  @override
+  void dispose() {
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: SizedBox(
+        height: widget.height,
+        child: Opacity(
+          opacity: _opacityTween!.evaluate(animation!),
+          child: _opacityTween!.evaluate(animation!) != 0
+              ? _AnimatedCircles(
+                  color: widget.color,
+                  height: widget.height,
+                )
+              : null,
+        ),
+      ),
+    );
+  }
+
+  @override
+  void forEachTween(visitor) {
+    _opacityTween = visitor(
+      _opacityTween,
+      widget.visible ? 1.0 : 0.0,
+      (dynamic value) => Tween<double>(begin: value as double),
+    ) as Tween<double>?;
+  }
+}
+
+class _AnimatedCircles extends StatefulWidget {
+  final Color color;
+  final double height;
+
+  const _AnimatedCircles({
+    required this.color,
+    required this.height,
+    Key? key,
+  }) : super(key: key);
+
+  @override
+  _AnimatedCirclesState createState() => _AnimatedCirclesState();
+}
+
+class _AnimatedCirclesState extends State<_AnimatedCircles>
+    with SingleTickerProviderStateMixin {
+  late Animation<double> _thinkingAnimation;
+  late AnimationController _thinkingController;
+
+  @override
+  void initState() {
+    super.initState();
+    _thinkingController = AnimationController(
+        duration: const Duration(milliseconds: 500), vsync: this)
+      ..addStatusListener((status) {
+        // This bit ensures that the animation reverses course rather than
+        // stopping.
+        if (status == AnimationStatus.completed) _thinkingController.reverse();
+        if (status == AnimationStatus.dismissed) _thinkingController.forward();
+      });
+    _thinkingAnimation = Tween(begin: 0.0, end: widget.height).animate(
+        CurvedAnimation(parent: _thinkingController, curve: Curves.easeOut));
+    _thinkingController.forward();
+  }
+
+  @override
+  void dispose() {
+    _thinkingController.dispose();
+    super.dispose();
+  }
+
+  Widget _buildCircle() {
+    return Container(
+      width: widget.height,
+      height: widget.height,
+      decoration: BoxDecoration(
+        border: Border.all(
+          color: widget.color,
+          width: 2.0,
+        ),
+        borderRadius: BorderRadius.all(const Radius.circular(5.0)),
+      ),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedBuilder(
+      animation: _thinkingAnimation,
+      builder: (context, child) {
+        return Row(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            _buildCircle(),
+            SizedBox(width: _thinkingAnimation.value),
+            _buildCircle(),
+            SizedBox(width: _thinkingAnimation.value),
+            _buildCircle(),
+            SizedBox(width: _thinkingAnimation.value),
+            _buildCircle(),
+            SizedBox(width: _thinkingAnimation.value),
+            _buildCircle(),
+          ],
+        );
+      },
+    );
+  }
+}

pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.7.0"
+    version: "2.8.1"
   boolean_selector:
     dependency: transitive
     description:
@@ -50,6 +50,20 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.2.0"
+  ffi:
+    dependency: transitive
+    description:
+      name: ffi
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.2"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "6.1.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -60,6 +74,18 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_web_plugins:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.6.3"
   matcher:
     dependency: transitive
     description:
@@ -88,6 +114,48 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.8.0"
+  path_provider_linux:
+    dependency: transitive
+    description:
+      name: path_provider_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.2"
+  path_provider_platform_interface:
+    dependency: transitive
+    description:
+      name: path_provider_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
+  path_provider_windows:
+    dependency: transitive
+    description:
+      name: path_provider_windows
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.3"
+  platform:
+    dependency: transitive
+    description:
+      name: platform
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.2"
+  plugin_platform_interface:
+    dependency: transitive
+    description:
+      name: plugin_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
+  process:
+    dependency: transitive
+    description:
+      name: process
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "4.2.3"
   provider:
     dependency: "direct main"
     description:
@@ -95,6 +163,48 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "5.0.0"
+  shared_preferences:
+    dependency: "direct main"
+    description:
+      name: shared_preferences
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.6"
+  shared_preferences_linux:
+    dependency: transitive
+    description:
+      name: shared_preferences_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.2"
+  shared_preferences_macos:
+    dependency: transitive
+    description:
+      name: shared_preferences_macos
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.2"
+  shared_preferences_platform_interface:
+    dependency: transitive
+    description:
+      name: shared_preferences_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  shared_preferences_web:
+    dependency: transitive
+    description:
+      name: shared_preferences_web
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
+  shared_preferences_windows:
+    dependency: transitive
+    description:
+      name: shared_preferences_windows
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.2"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -141,7 +251,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.1"
+    version: "0.4.2"
   typed_data:
     dependency: transitive
     description:
@@ -156,6 +266,20 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.0"
+  win32:
+    dependency: transitive
+    description:
+      name: win32
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.2.5"
+  xdg_directories:
+    dependency: transitive
+    description:
+      name: xdg_directories
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.2.0"
 sdks:
-  dart: ">=2.12.0 <3.0.0"
-  flutter: ">=1.16.0"
+  dart: ">=2.13.0 <3.0.0"
+  flutter: ">=2.0.0"

pubspec.yaml

-name: reversi
+name: simpler_reversi
 description: A reversi game application.
 publish_to: 'none'
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
   provider: ^5.0.0
+  shared_preferences: ^2.0.6
 
 dev_dependencies:
   flutter_test: