/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");

/**** 
* Classes
****/ 
// Tile class for each tile on the board
var Tile = Container.expand(function () {
	var self = Container.call(this);
	self.value = 3; // default, will be set on creation
	self.row = 0;
	self.col = 0;
	// Create and attach a box asset for the tile
	self.tileBox = self.attachAsset('tileBox', {
		width: 400,
		height: 400,
		color: 0xeeeeee,
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Text for the tile value
	self.valueText = new Text2('3', {
		size: 120,
		fill: 0x333333
	});
	self.valueText.anchor.set(0.5, 0.5);
	self.addChild(self.valueText);
	// Set tile value and update appearance
	self.setValue = function (val) {
		self.value = val;
		self.valueText.setText(val + '');
		// Color by value
		var color = 0xeeeeee;
		if (val === 3) color = 0xF9F6F2;else if (val === 6) color = 0xEDE0C8;else if (val === 12) color = 0xF2B179;else if (val === 24) color = 0xF59563;else if (val === 48) color = 0xF67C5F;else if (val === 96) color = 0xF65E3B;else if (val === 192) color = 0xEDCF72;else if (val === 384) color = 0xEDCC61;else if (val === 768) color = 0xEDC850;else if (val === 1536) color = 0xEDC53F;else if (val === 3072) color = 0xEDC22E;
		self.tileBox.color = color;
	};
	// Animate pop-in
	self.pop = function () {
		self.scaleX = self.scaleY = 0.2;
		tween(self, {
			scaleX: 1,
			scaleY: 1
		}, {
			duration: 120,
			easing: tween.easeOut
		});
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0xf7f7f7
});

/**** 
* Game Code
****/ 
// --- Constants ---
var GRID_SIZE = 4;
var TILE_SIZE = 400;
var TILE_MARGIN = 32;
var BOARD_SIZE = GRID_SIZE * TILE_SIZE + (GRID_SIZE + 1) * TILE_MARGIN;
var BOARD_X = (2048 - BOARD_SIZE) / 2;
var BOARD_Y = (2732 - BOARD_SIZE) / 2 + 100;
// --- State ---
var board = []; // 2D array of tiles or null
var tileNodes = []; // 2D array of Tile objects or null
var score = 0;
var bestTile = 3;
var moving = false; // Prevent input during animation
// --- GUI ---
var scoreTxt = new Text2('Score: 0', {
	size: 90,
	fill: 0x333333
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
var bestTxt = new Text2('Best: 3', {
	size: 60,
	fill: 0x888888
});
bestTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(bestTxt);
bestTxt.y = 110;
// --- Board background ---
var boardBg = LK.getAsset('boardBg', {
	width: BOARD_SIZE,
	height: BOARD_SIZE,
	color: 0xbbb9b6,
	anchorX: 0,
	anchorY: 0,
	x: BOARD_X,
	y: BOARD_Y
});
game.addChild(boardBg);
// --- Board grid background tiles ---
for (var r = 0; r < GRID_SIZE; r++) {
	for (var c = 0; c < GRID_SIZE; c++) {
		var cellBg = LK.getAsset('cellBg', {
			width: TILE_SIZE,
			height: TILE_SIZE,
			color: 0xcdc1b4,
			anchorX: 0.5,
			anchorY: 0.5,
			x: BOARD_X + TILE_MARGIN + c * (TILE_SIZE + TILE_MARGIN) + TILE_SIZE / 2,
			y: BOARD_Y + TILE_MARGIN + r * (TILE_SIZE + TILE_MARGIN) + TILE_SIZE / 2
		});
		game.addChild(cellBg);
	}
}
// --- Helper: get position for a tile ---
function getTilePos(row, col) {
	return {
		x: BOARD_X + TILE_MARGIN + col * (TILE_SIZE + TILE_MARGIN) + TILE_SIZE / 2,
		y: BOARD_Y + TILE_MARGIN + row * (TILE_SIZE + TILE_MARGIN) + TILE_SIZE / 2
	};
}
// --- Helper: spawn a new tile (3 or 6) in a random empty cell ---
function spawnTile() {
	var empties = [];
	for (var r = 0; r < GRID_SIZE; r++) {
		for (var c = 0; c < GRID_SIZE; c++) {
			if (board[r][c] === null) {
				empties.push({
					r: r,
					c: c
				});
			}
		}
	}
	if (empties.length === 0) return false;
	var idx = Math.floor(Math.random() * empties.length);
	var pos = empties[idx];
	var val = Math.random() < 0.8 ? 3 : 6;
	addTile(pos.r, pos.c, val, true);
	return true;
}
// --- Helper: add a tile to the board and scene ---
function addTile(row, col, value, animate) {
	var tile = new Tile();
	tile.setValue(value);
	tile.row = row;
	tile.col = col;
	var pos = getTilePos(row, col);
	tile.x = pos.x;
	tile.y = pos.y;
	board[row][col] = value;
	tileNodes[row][col] = tile;
	game.addChild(tile);
	if (animate) tile.pop();
}
// --- Helper: remove a tile from the board and scene ---
function removeTile(row, col) {
	if (tileNodes[row][col]) {
		tileNodes[row][col].destroy();
	}
	board[row][col] = null;
	tileNodes[row][col] = null;
}
// --- Helper: update score and best tile display ---
function updateScore(add) {
	score += add;
	scoreTxt.setText('Score: ' + score);
}
function updateBestTile(val) {
	if (val > bestTile) {
		bestTile = val;
		bestTxt.setText('Best: ' + bestTile);
	}
}
// --- Helper: check if any moves are possible ---
function movesAvailable() {
	for (var r = 0; r < GRID_SIZE; r++) {
		for (var c = 0; c < GRID_SIZE; c++) {
			if (board[r][c] === null) return true;
			var v = board[r][c];
			// Check right
			if (c < GRID_SIZE - 1 && board[r][c + 1] === v) return true;
			// Check down
			if (r < GRID_SIZE - 1 && board[r + 1][c] === v) return true;
		}
	}
	return false;
}
// --- Helper: check for win (tile 3072) ---
function checkWin() {
	for (var r = 0; r < GRID_SIZE; r++) {
		for (var c = 0; c < GRID_SIZE; c++) {
			if (board[r][c] === 3072) {
				LK.showYouWin();
				return true;
			}
		}
	}
	return false;
}
// --- Helper: move/merge tiles in a direction ---
// dir: {x: -1, y:0} for left, {x:1,y:0} for right, etc.
function moveTiles(dir) {
	if (moving) return;
	moving = true;
	var moved = false;
	var merged = [];
	for (var r = 0; r < GRID_SIZE; r++) {
		merged[r] = [];
		for (var c = 0; c < GRID_SIZE; c++) merged[r][c] = false;
	}
	// Order of traversal depends on direction
	var startR = dir.y > 0 ? GRID_SIZE - 1 : 0;
	var endR = dir.y > 0 ? -1 : GRID_SIZE;
	var stepR = dir.y > 0 ? -1 : 1;
	var startC = dir.x > 0 ? GRID_SIZE - 1 : 0;
	var endC = dir.x > 0 ? -1 : GRID_SIZE;
	var stepC = dir.x > 0 ? -1 : 1;
	var movedTiles = [];
	for (var i = 0; i < GRID_SIZE * GRID_SIZE; i++) {
		var r = dir.y !== 0 ? startR + stepR * (i % GRID_SIZE) : i / GRID_SIZE | 0;
		var c = dir.x !== 0 ? startC + stepC * (i % GRID_SIZE) : i % GRID_SIZE;
		r = Math.max(0, Math.min(GRID_SIZE - 1, r));
		c = Math.max(0, Math.min(GRID_SIZE - 1, c));
		if (board[r][c] === null) continue;
		var nr = r,
			nc = c;
		while (true) {
			var tr = nr + dir.y,
				tc = nc + dir.x;
			if (tr < 0 || tr >= GRID_SIZE || tc < 0 || tc >= GRID_SIZE) break;
			if (board[tr][tc] === null) {
				nr = tr;
				nc = tc;
			} else if (board[tr][tc] === board[r][c] && !merged[tr][tc]) {
				// Only merge if values are exactly equal
				nr = tr;
				nc = tc;
				break;
			} else {
				// Prevent merge if values are not exactly equal
				break;
			}
		}
		if (nr !== r || nc !== c) {
			moved = true;
			movedTiles.push({
				fromR: r,
				fromC: c,
				toR: nr,
				toC: nc
			});
		}
	}
	// Actually move and merge
	var toRemove = [];
	var toAdd = [];
	for (var m = 0; m < movedTiles.length; m++) {
		var move = movedTiles[m];
		var val = board[move.fromR][move.fromC];
		var destVal = board[move.toR][move.toC];
		var mergedHere = false;
		if (board[move.toR][move.toC] === board[move.fromR][move.fromC] && !merged[move.toR][move.toC]) {
			// Only merge if values are exactly equal
			val = board[move.toR][move.toC] + board[move.fromR][move.fromC];
			merged[move.toR][move.toC] = true;
			toRemove.push({
				r: move.fromR,
				c: move.fromC
			});
			toRemove.push({
				r: move.toR,
				c: move.toC
			});
			toAdd.push({
				r: move.toR,
				c: move.toC,
				val: val,
				merged: true
			});
			updateScore(val);
			updateBestTile(val);
			if (val === 3072) {
				LK.setTimeout(function () {
					LK.showYouWin();
				}, 400);
			}
		} else {
			// Just move
			toRemove.push({
				r: move.fromR,
				c: move.fromC
			});
			toAdd.push({
				r: move.toR,
				c: move.toC,
				val: board[move.fromR][move.fromC],
				merged: false
			});
		}
	}
	// Animate all moves
	var animCount = 0;
	for (var m = 0; m < movedTiles.length; m++) {
		var move = movedTiles[m];
		var tile = tileNodes[move.fromR][move.fromC];
		var pos = getTilePos(move.toR, move.toC);
		animCount++;
		tween(tile, {
			x: pos.x,
			y: pos.y
		}, {
			duration: 120,
			easing: tween.easeInOut,
			onFinish: function onFinish() {
				animCount--;
				if (animCount === 0) finishMove();
			}
		});
	}
	if (movedTiles.length === 0) {
		moving = false;
		return;
	}
	function finishMove() {
		// Remove old tiles
		for (var i = 0; i < toRemove.length; i++) {
			removeTile(toRemove[i].r, toRemove[i].c);
		}
		// Add new tiles
		for (var i = 0; i < toAdd.length; i++) {
			addTile(toAdd[i].r, toAdd[i].c, toAdd[i].val, toAdd[i].merged);
		}
		// Spawn new tile
		spawnTile();
		// Check for game over
		if (!movesAvailable()) {
			LK.setTimeout(function () {
				LK.showGameOver();
			}, 400);
		}
		moving = false;
	}
	// If no animation (should not happen), call finishMove immediately
	if (animCount === 0) finishMove();
}
// --- Input handling ---
// Touch/drag swipe detection
var touchStartX = null,
	touchStartY = null,
	touchStartTime = null;
game.down = function (x, y, obj) {
	touchStartX = x;
	touchStartY = y;
	touchStartTime = Date.now();
};
game.up = function (x, y, obj) {
	if (touchStartX === null || moving) return;
	var dx = x - touchStartX;
	var dy = y - touchStartY;
	var adx = Math.abs(dx),
		ady = Math.abs(dy);
	if (adx < 50 && ady < 50) {
		touchStartX = null;
		touchStartY = null;
		return;
	}
	if (adx > ady) {
		if (dx > 0) moveTiles({
			x: 1,
			y: 0
		}); // right
		else moveTiles({
			x: -1,
			y: 0
		}); // left
	} else {
		if (dy > 0) moveTiles({
			x: 0,
			y: 1
		}); // down
		else moveTiles({
			x: 0,
			y: -1
		}); // up
	}
	touchStartX = null;
	touchStartY = null;
};
// Keyboard controls (for desktop)
game.move = function (x, y, obj) {
	// No-op for drag, but we want to support keyboard
	if (obj && obj.event && obj.event.type === 'keydown' && !moving) {
		var key = obj.event.key;
		if (key === 'ArrowLeft') moveTiles({
			x: -1,
			y: 0
		});else if (key === 'ArrowRight') moveTiles({
			x: 1,
			y: 0
		});else if (key === 'ArrowUp') moveTiles({
			x: 0,
			y: -1
		});else if (key === 'ArrowDown') moveTiles({
			x: 0,
			y: 1
		});
	}
};
// --- Game initialization ---
function resetGame() {
	// Clear board
	for (var r = 0; r < GRID_SIZE; r++) {
		for (var c = 0; c < GRID_SIZE; c++) {
			if (tileNodes[r] && tileNodes[r][c]) {
				tileNodes[r][c].destroy();
			}
		}
	}
	board = [];
	tileNodes = [];
	for (var r = 0; r < GRID_SIZE; r++) {
		board[r] = [];
		tileNodes[r] = [];
		for (var c = 0; c < GRID_SIZE; c++) {
			board[r][c] = null;
			tileNodes[r][c] = null;
		}
	}
	score = 0;
	bestTile = 3;
	scoreTxt.setText('Score: 0');
	bestTxt.setText('Best: 3');
	moving = false;
	// Spawn two tiles
	spawnTile();
	spawnTile();
}
resetGame();
// --- Game tick (not used, but required for LK) ---
game.update = function () {
	// No per-frame logic needed
};

===================================================================
--- original.js
+++ change.js