Add minedigger example

A very basic minesweeper clone. Currently only tested in linux.

BUG=none
R=abarth@chromium.org, eseidel@chromium.org

Review URL: https://codereview.chromium.org/1196213012.

examples/mine_digger/mine_digger.dart

+// Copyright 2015 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:sky' as sky;
+import 'dart:math';
+
+import 'package:sky/rendering/flex.dart';
+import 'package:sky/widgets/basic.dart';
+import 'package:sky/painting/text_style.dart';
+
+// Classic minesweeper-inspired game. The mouse controls are standard except
+// for left + right combo which is not implemented. For touch, the duration of
+// the pointer determines probing versus flagging.
+//
+// There are only 3 classes to understand. Game, which is contains all the 
+// logic and two UI classes: CoveredMineNode and ExposedMineNode, none of them
+// holding state.
+
+class Game {
+  static const int rows = 9;
+  static const int cols = 9;
+  static const int totalMineCount = 11;
+
+  static const int coveredCell = 0;
+  static const int explodedCell = 1;
+  static const int clearedCell = 2;
+  static const int flaggedCell = 3;
+  static const int shownCell = 4;
+
+  static final List<TextStyle> textStyles = new List<TextStyle>();
+
+  final App app;
+
+  bool alive;
+  bool hasWon;
+  int detectedCount;
+  int randomSeed;
+
+  // |cells| keeps track of the positions of the mines.
+  List<List<bool>> cells;
+  // |uiState| keeps track of the visible player progess.
+  List<List<int>> uiState;
+
+  Game(this.app) {
+    randomSeed = 22;
+    // Colors for each mine count:
+    // 0 - none, 1 - blue, 2-green, 3-red, 4-black, 5-dark red .. etc.
+    textStyles.add(
+      new TextStyle(color: const Color(0xFF555555), fontWeight: bold));
+    textStyles.add(
+      new TextStyle(color: const Color(0xFF0094FF), fontWeight: bold));
+    textStyles.add(
+      new TextStyle(color: const Color(0xFF13A023), fontWeight: bold));
+    textStyles.add(
+      new TextStyle(color: const Color(0xFFDA1414), fontWeight: bold));
+    textStyles.add(
+      new TextStyle(color: const Color(0xFF1E2347), fontWeight: bold));
+    textStyles.add(
+      new TextStyle(color: const Color(0xFF7F0037), fontWeight: bold));
+    textStyles.add(
+      new TextStyle(color: const Color(0xFFE93BE9), fontWeight: bold));
+    initialize();
+  }
+
+  void initialize() {
+    alive = true;
+    hasWon = false;
+    detectedCount = 0;
+    // Build the arrays.
+    cells = new List<List<bool>>();
+    uiState = new List<List<int>>();
+    for (int iy = 0; iy != rows; iy++) {
+      cells.add(new List<bool>());
+      uiState.add(new List<int>());
+      for (int ix = 0; ix != cols; ix++) {
+        cells[iy].add(false);
+        uiState[iy].add(coveredCell);
+      }
+    }
+    // Place the mines.
+    Random random = new Random(++randomSeed);
+    for (int mc = 0; mc != totalMineCount; mc++) {
+      int rx = random.nextInt(rows);
+      int ry = random.nextInt(cols);
+      if (cells[ry][rx]) {
+        // Mine already there. Try again.
+        --mc;
+      } else {
+        cells[ry][rx] = true;
+      }
+    }
+  }
+
+  Widget generateBoard() {
+    bool hasCoveredCell = false;
+    List<Flex> flexRows = new List<Flex>();
+    for (int iy = 0; iy != 9; iy++) {
+      List<Component> row = new List<Component>();
+      for (int ix = 0; ix != 9; ix++) {
+        int state = uiState[iy][ix];
+        int count = mineCount(ix, iy);
+
+        if (!alive) {
+          if (state != explodedCell)
+            state = cells[iy][ix] ? shownCell : state;
+        }
+
+        if (state == coveredCell) {
+          row.add(new CoveredMineNode(
+            this,
+            flagged: false,
+            posX: ix, posY: iy));
+            // Mutating |hasCoveredCell| here is hacky, but convenient, same
+            // goes for mutating |hasWon| below.
+            hasCoveredCell = true;
+        } else if (state == flaggedCell) {
+          row.add(new CoveredMineNode(
+            this,
+            flagged: true,
+            posX: ix, posY: iy));
+        } else {
+          row.add(new ExposedMineNode(
+            state: state,
+            count: count));
+        }
+      }
+      flexRows.add(
+        new Flex(
+          row,
+          direction: FlexDirection.horizontal,
+          justifyContent: FlexJustifyContent.center,
+          key: 'flex_row($iy)'
+        ));
+    }
+
+    if (!hasCoveredCell) {
+      // all cells uncovered. Are all mines flagged?
+      if ((detectedCount == totalMineCount) && alive) {
+        hasWon = true;
+      }
+    }
+
+    return new Container(
+      key: 'minefield',
+      padding: new EdgeDims.all(10.0),
+      margin: new EdgeDims.all(10.0),
+      decoration: new BoxDecoration(backgroundColor: const Color(0xFF6B6B6B)),
+      child: new Flex(
+        flexRows,
+        direction: FlexDirection.vertical,
+        key: 'flxv'));
+  }
+
+  Widget generateUI() {
+    Widget board = generateBoard();
+    String banner = hasWon ?
+      'Awesome!!' : alive ?
+        'Mine Digger [$detectedCount-$totalMineCount]': 'Kaboom! [press here]';
+
+    return new Flex([
+      new Container(
+        padding: new EdgeDims.all(10.0),
+        margin: new EdgeDims.all(10.0),
+        decoration: new BoxDecoration(backgroundColor: const Color(0xFFC0C0C0)),
+        child: new Listener(
+          onPointerDown: handleBannerPointerDown,
+          child: new Text(banner))),
+      board,
+      new Container(
+        height: 100.0, width: 100.0,
+        decoration: new BoxDecoration(backgroundColor: const Color(0xFFCC1111))
+      )
+    ],
+    direction: FlexDirection.vertical,
+    justifyContent: FlexJustifyContent.spaceAround);
+  }
+
+  void handleBannerPointerDown(sky.PointerEvent event) {
+    initialize();
+    app.setState((){});
+  }
+
+  // User action. The user uncovers the cell which can cause losing the game.
+  void probe(int x, int y) {
+    if (!alive)
+      return;
+    if (uiState[y][x] == flaggedCell)
+      return;
+    // Allowed to probe.
+    if (cells[y][x]) {
+      // Probed on a mine --> dead!!
+      uiState[y][x] = explodedCell;
+      alive = false;
+    } else {
+      // No mine, uncover nearby if possible.
+      cull(x, y);
+    }
+    app.setState((){});
+  }
+
+  // User action. The user is sure a mine is at this location.
+  void flag(int x, int y) {
+    if (uiState[y][x] == flaggedCell) {
+      uiState[y][x] = coveredCell;
+      --detectedCount;
+    } else {
+      uiState[y][x] = flaggedCell;
+      ++detectedCount;
+    }
+    app.setState((){});
+  }
+
+  // Recursively uncovers cells whose totalMineCount is zero.
+  void cull(int x, int y) {
+    if ((x < 0) || (x > rows - 1))
+      return;
+    if ((y < 0) || (y > cols - 1))
+      return;
+
+    if (uiState[y][x] == clearedCell)
+      return;
+    uiState[y][x] = clearedCell;
+
+    if (mineCount(x, y) > 0)
+      return;
+
+    cull(x - 1, y);
+    cull(x + 1, y);
+    cull(x, y - 1);
+    cull(x, y + 1 );
+    cull(x - 1, y - 1);
+    cull(x + 1, y + 1);
+    cull(x + 1, y - 1);
+    cull(x - 1, y + 1);
+  }
+
+  int mineCount(int x, int y) {
+    int count = 0;
+    int my = cols - 1;
+    int mx = rows - 1;
+
+    count += x > 0 ? bombs(x - 1, y) : 0;
+    count += x < mx ? bombs(x + 1, y) : 0;
+    count += y > 0 ? bombs(x, y - 1) : 0;
+    count += y < my ? bombs(x, y + 1 ) : 0;
+
+    count += (x > 0) && (y > 0) ? bombs(x - 1, y - 1) : 0;
+    count += (x < mx) && (y < my) ? bombs(x + 1, y + 1) : 0;
+    count += (x < mx) && (y > 0) ? bombs(x + 1, y - 1) : 0;
+    count += (x > 0) && (y < my) ? bombs(x - 1, y + 1) : 0;
+
+    return count;
+  }
+
+  int bombs(int x, int y) {
+    return cells[y][x] ? 1 : 0;
+  }
+}
+
+Widget makeCell(Widget widget) {
+  return new Container(
+    padding: new EdgeDims.all(1.0),
+    height: 27.0, width: 27.0,
+    decoration: new BoxDecoration(backgroundColor: const Color(0xFFC0C0C0)),
+    margin: new EdgeDims.all(2.0),
+    child: widget);
+}
+
+Widget makeInnerCell(Widget widget) {
+  return new Container(
+    padding: new EdgeDims.all(1.0),
+    margin: new EdgeDims.all(3.0),
+    height: 17.0, width: 17.0,
+    child: widget);
+}
+
+class CoveredMineNode extends Component {
+  final Game game;
+  final bool flagged;
+  final int posX;
+  final int posY;
+  Stopwatch stopwatch;
+
+  CoveredMineNode(this.game, {this.flagged, this.posX, this.posY});
+
+  void _handlePointerDown(sky.PointerEvent event) {
+    if (event.buttons == 1) {
+      game.probe(posX, posY);
+    } else if (event.buttons == 2) {
+      game.flag(posX, posY);
+    } else {
+      // Touch event.
+      stopwatch = new Stopwatch()..start();
+    }
+  }
+
+  void _handlePointerUp(sky.PointerEvent event) {
+    if (stopwatch == null)
+      return;
+    // Pointer down was a touch event.
+    var ms = stopwatch.elapsedMilliseconds;
+    if (stopwatch.elapsedMilliseconds < 250) {
+      game.probe(posX, posY);
+    } else {
+      // Long press flags.
+      game.flag(posX, posY);
+    }
+    stopwatch = null;
+  }
+
+  Widget build() {
+    Widget text = flagged ?
+      makeInnerCell(new StyledText(elements : [Game.textStyles[5], '\u2691'])) :
+      null;
+
+    Container inner = new Container(
+      margin: new EdgeDims.all(2.0),
+      height: 17.0, width: 17.0,
+      decoration: new BoxDecoration(backgroundColor: const Color(0xFFD9D9D9)),
+      child: text);
+
+    return makeCell(new Listener(
+      child: inner,
+      onPointerDown: _handlePointerDown,
+      onPointerUp: _handlePointerUp));
+  }
+}
+
+class ExposedMineNode extends Component {
+  final int state;
+  final int count;
+
+  ExposedMineNode({this.state, this.count});
+
+  Widget build() {
+    StyledText text;
+    if (state == Game.clearedCell) {
+      // Uncovered cell with nearby mine count.
+      if (count != 0)
+        text = new StyledText(elements : [Game.textStyles[count], '$count']);
+    } else {
+      // Exploded mine or shown mine for 'game over'.
+      int color = state == Game.explodedCell ? 3 : 0;
+      text = new StyledText(elements : [Game.textStyles[color], '\u2600']);
+    }
+
+    return makeCell(makeInnerCell(text));
+  }
+}
+
+class MineDiggerApp extends App {
+  Game game;
+
+  MineDiggerApp() {
+    game = new Game(this);
+  }
+
+  Widget build() {
+    return game.generateUI();
+  }
+}
+
+void main() {
+  runApp(new MineDiggerApp());
+}