add task solution

src/index.html

@@ -65,6 +65,9 @@ <h1>2048</h1>
         </p>
       </div>
     </div>
-    <script src="scripts/main.js"></script>
+    <script
+      type="module"
+      src="scripts/main.js"
+    ></script>
   </body>
 </html>

src/scripts/main.js

@@ -1,7 +1,199 @@
 'use strict';
 
-// Uncomment the next lines to use your game instance in the browser
-// const Game = require('../modules/Game.class');
-// const game = new Game();
+class Game {
+  static SIZE = 4;
+  static TILE_PROBABILITY = 0.9;
+  static WIN_TILE_VALUE = 2048;
 
-// Write your code here
+  constructor(initialState = null) {
+    this.score = 0;
+    this.status = 'idle';
+
+    this.initialState = initialState
+      ? JSON.parse(JSON.stringify(initialState))
+      : null;
+
+    this.state = initialState
+      ? JSON.parse(JSON.stringify(initialState))
+      : this.createEmptyBoard();
+  }
+
+  createEmptyBoard() {
+    return Array.from({ length: Game.SIZE }, () => Array(Game.SIZE).fill(0));
+  }
+
+  addRandomTile() {
+    const emptyTiles = [];
+
+    for (let row = 0; row < Game.SIZE; row++) {
+      for (let col = 0; col < Game.SIZE; col++) {
+        if (this.state[row][col] === 0) {
+          emptyTiles.push({ row, col });
+        }
+      }
+    }
+
+    if (emptyTiles.length > 0) {
+      const { row, col } =
+        emptyTiles[Math.floor(Math.random() * emptyTiles.length)];
+
+      this.state[row][col] = Math.random() < Game.TILE_PROBABILITY ? 2 : 4;
+    }
+  }
+
+  checkGameState() {
+    if (this.state.some((row) => row.includes(Game.WIN_TILE_VALUE))) {
+      this.status = 'win';
+
+      return;
+    }
+
+    if (!this.canMove()) {
+      this.status = 'lose';
+    }
+  }
+
+  canMove() {
+    for (let row = 0; row < Game.SIZE; row++) {
+      for (let col = 0; col < Game.SIZE; col++) {
+        if (this.state[row][col] === 0) {
+          return true;
+        }
+
+        if (
+          (row < Game.SIZE - 1 &&
+            this.state[row][col] === this.state[row + 1][col]) ||
+          (col < Game.SIZE - 1 &&
+            this.state[row][col] === this.state[row][col + 1])
+        ) {
+          return true;
+        }
+      }
+    }
+
+    return false;
+  }
+
+  move(direction) {
+    if (this.status !== 'playing') {
+      return;
+    }
+
+    const previousState = JSON.stringify(this.state);
+
+    if (direction === 'left') {
+      this.state = this.shiftLeft(this.state);
+    }
+
+    if (direction === 'right') {
+      this.state = this.shiftRight(this.state);
+    }
+
+    if (direction === 'up') {
+      this.state = this.shiftUp(this.state);
+    }
+
+    if (direction === 'down') {
+      this.state = this.shiftDown(this.state);
+    }
+
+    if (JSON.stringify(this.state) !== previousState) {
+      this.addRandomTile();
+    }
+
+    this.checkGameState();
+  }
+
+  shiftLeft(state) {
+    return state.map((row) => this.compressRow(row));
+  }
+
+  shiftRight(state) {
+    return state.map((row) => this.compressRow([...row].reverse()).reverse());
+  }
+
+  shiftUp(state) {
+    const transposed = this.transpose(state);
+    const shifted = this.shiftLeft(transposed);
+
+    return this.transpose(shifted);
+  }
+
+  shiftDown(state) {
+    const transposed = this.transpose(state);
+    const shifted = this.shiftRight(transposed);
+
+    return this.transpose(shifted);
+  }
+
+  compressRow(row) {
+    const filtered = row.filter((value) => value !== 0);
+
+    for (let i = 0; i < filtered.length - 1; i++) {
+      if (filtered[i] === filtered[i + 1]) {
+        filtered[i] *= 2;
+        this.score += filtered[i];
+        filtered[i + 1] = 0;
+      }
+    }
+
+    const filtered2 = filtered.filter((value) => value !== 0);
+
+    return [...filtered2, ...Array(Game.SIZE - filtered2.length).fill(0)];
+  }
+
+  transpose(matrix) {
+    return matrix[0].map((_, colIndex) => matrix.map((row) => row[colIndex]));
+  }
+
+  moveLeft() {
+    this.move('left');
+  }
+
+  moveRight() {
+    this.move('right');
+  }
+
+  moveUp() {
+    this.move('up');
+  }
+
+  moveDown() {
+    this.move('down');
+  }
+
+  getState() {
+    return this.state;
+  }
+
+  getScore() {
+    return this.score;
+  }
+
+  getStatus() {
+    return this.status;
+  }
+
+  start() {
+    if (this.status === 'idle') {
+      this.resetGame();
+      this.status = 'playing';
+      this.addRandomTile();
+      this.addRandomTile();
+    }
+  }
+
+  restart() {
+    this.resetGame();
+    this.status = 'idle';
+  }
+
+  resetGame() {
+    this.state = this.initialState
+      ? JSON.parse(JSON.stringify(this.initialState))
+      : this.createEmptyBoard();
+    this.score = 0;
+  }
+}
+
+module.exports = Game;