/****
* Classes
****/
//<Assets used in the game will automatically appear here>
// Tile class to represent each tile in the game
var Tile = Container.expand(function () {
  var self = Container.call(this);
  self.value = 0;
  self.text = new Text2('0', {
    size: 100,
    fill: "#ffffff"
  });
  self.text.anchor.set(0.5, 0.5);
  self.addChild(self.text);
  self.updateValue = function (newValue) {
    self.value = newValue;
    self.text.setText(newValue);
  };
  self.merge = function (otherTile) {
    if (self.value === otherTile.value) {
      self.updateValue(self.value * 2);
      otherTile.updateValue(0);
      return true;
    }
    return false;
  };
  return self;
});

/****
* Initialize Game
****/
var game = new LK.Game({
  backgroundColor: 0x000000 //Init game with black background 
});

/****
* Game Code
****/
// Game variables
var gridSize = 4;
var tileSize = 200;
var tilePadding = 20;
var board = [];
var score = 0;
var scoreTxt = new Text2('0', {
  size: 150,
  fill: "#ffffff"
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
// Initialize board
function initBoard() {
  for (var i = 0; i < gridSize; i++) {
    board[i] = [];
    for (var j = 0; j < gridSize; j++) {
      var tile = new Tile();
      tile.x = j * (tileSize + tilePadding) + tilePadding;
      tile.y = i * (tileSize + tilePadding) + tilePadding;
      board[i][j] = tile;
      game.addChild(tile);
    }
  }
  addRandomTile();
  addRandomTile();
}
// Add a random tile to the board
function addRandomTile() {
  var emptyTiles = [];
  for (var i = 0; i < gridSize; i++) {
    for (var j = 0; j < gridSize; j++) {
      if (board[i][j].value === 0) {
        emptyTiles.push(board[i][j]);
      }
    }
  }
  if (emptyTiles.length > 0) {
    var randomTile = emptyTiles[Math.floor(Math.random() * emptyTiles.length)];
    randomTile.updateValue(Math.random() < 0.9 ? 2 : 4);
  }
}
// Handle swipe events
function handleSwipe(direction) {
  var moved = false;
  if (direction === 'left' || direction === 'right') {
    for (var i = 0; i < gridSize; i++) {
      var row = board[i];
      if (direction === 'right') row.reverse();
      moved = mergeTiles(row) || moved;
      if (direction === 'right') row.reverse();
    }
  } else if (direction === 'up' || direction === 'down') {
    for (var j = 0; j < gridSize; j++) {
      var column = [];
      for (var i = 0; i < gridSize; i++) {
        column.push(board[i][j]);
      }
      if (direction === 'down') column.reverse();
      moved = mergeTiles(column) || moved;
      if (direction === 'down') column.reverse();
    }
  }
  if (moved) {
    addRandomTile();
    updateScore();
  }
}
// Merge tiles in a row or column
function mergeTiles(tiles) {
  var moved = false;
  for (var i = 0; i < tiles.length - 1; i++) {
    for (var j = i + 1; j < tiles.length; j++) {
      if (tiles[j].value === 0) continue;
      if (tiles[i].merge(tiles[j])) {
        moved = true;
        break;
      } else if (tiles[i].value === 0) {
        tiles[i].updateValue(tiles[j].value);
        tiles[j].updateValue(0);
        moved = true;
      } else {
        break;
      }
    }
  }
  return moved;
}
// Update score
function updateScore() {
  score = 0;
  for (var i = 0; i < gridSize; i++) {
    for (var j = 0; j < gridSize; j++) {
      score += board[i][j].value;
    }
  }
  scoreTxt.setText(score);
}
// Initialize the game
initBoard();
// Handle swipe events
game.down = function (x, y, obj) {
  var startX = x;
  var startY = y;
  game.move = function (x, y, obj) {
    var deltaX = x - startX;
    var deltaY = y - startY;
    if (Math.abs(deltaX) > Math.abs(deltaY)) {
      if (deltaX > 50) {
        handleSwipe('right');
      } else if (deltaX < -50) {
        handleSwipe('left');
      }
    } else {
      if (deltaY > 50) {
        handleSwipe('down');
      } else if (deltaY < -50) {
        handleSwipe('up');
      }
    }
    game.move = null;
  };
};
game.up = function (x, y, obj) {
  game.move = null;
};
// Update game state
game.update = function () {
  // No continuous updates needed for this game
};