2048

2048/js/grid.js

@@ -0,0 +1,117 @@
+function Grid(size, previousState) {
+  this.size = size;
+  this.cells = previousState ? this.fromState(previousState) : this.empty();
+}
+
+// Build a grid of the specified size
+Grid.prototype.empty = function () {
+  var cells = [];
+
+  for (var x = 0; x < this.size; x++) {
+    var row = cells[x] = [];
+
+    for (var y = 0; y < this.size; y++) {
+      row.push(null);
+    }
+  }
+
+  return cells;
+};
+
+Grid.prototype.fromState = function (state) {
+  var cells = [];
+
+  for (var x = 0; x < this.size; x++) {
+    var row = cells[x] = [];
+
+    for (var y = 0; y < this.size; y++) {
+      var tile = state[x][y];
+      row.push(tile ? new Tile(tile.position, tile.value) : null);
+    }
+  }
+
+  return cells;
+};
+
+// Find the first available random position
+Grid.prototype.randomAvailableCell = function () {
+  var cells = this.availableCells();
+
+  if (cells.length) {
+    return cells[Math.floor(Math.random() * cells.length)];
+  }
+};
+
+Grid.prototype.availableCells = function () {
+  var cells = [];
+
+  this.eachCell(function (x, y, tile) {
+    if (!tile) {
+      cells.push({ x: x, y: y });
+    }
+  });
+
+  return cells;
+};
+
+// Call callback for every cell
+Grid.prototype.eachCell = function (callback) {
+  for (var x = 0; x < this.size; x++) {
+    for (var y = 0; y < this.size; y++) {
+      callback(x, y, this.cells[x][y]);
+    }
+  }
+};
+
+// Check if there are any cells available
+Grid.prototype.cellsAvailable = function () {
+  return !!this.availableCells().length;
+};
+
+// Check if the specified cell is taken
+Grid.prototype.cellAvailable = function (cell) {
+  return !this.cellOccupied(cell);
+};
+
+Grid.prototype.cellOccupied = function (cell) {
+  return !!this.cellContent(cell);
+};
+
+Grid.prototype.cellContent = function (cell) {
+  if (this.withinBounds(cell)) {
+    return this.cells[cell.x][cell.y];
+  } else {
+    return null;
+  }
+};
+
+// Inserts a tile at its position
+Grid.prototype.insertTile = function (tile) {
+  this.cells[tile.x][tile.y] = tile;
+};
+
+Grid.prototype.removeTile = function (tile) {
+  this.cells[tile.x][tile.y] = null;
+};
+
+Grid.prototype.withinBounds = function (position) {
+  return position.x >= 0 && position.x < this.size &&
+         position.y >= 0 && position.y < this.size;
+};
+
+Grid.prototype.serialize = function () {
+  var cellState = [];
+
+  for (var x = 0; x < this.size; x++) {
+    var row = cellState[x] = [];
+
+    for (var y = 0; y < this.size; y++) {
+      row.push(this.cells[x][y] ? this.cells[x][y].serialize() : null);
+    }
+  }
+
+  return {
+    size: this.size,
+    cells: cellState
+  };
+};