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

/**** 
* Classes
****/ 
var Barrier = Container.expand(function () {
	var self = Container.call(this);
	var barrierGraphics = self.attachAsset('tower', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	barrierGraphics.tint = 0x8B4513; // Brown tint for barriers
	self.health = 100; // Very high resistance
	self.maxHealth = 100;
	self.lastIntersecting = {};
	self.update = function () {
		// Check collision with zombies
		for (var i = 0; i < zombies.length; i++) {
			var zombie = zombies[i];
			var zombieId = zombies.indexOf(zombie);
			// Initialize last intersecting state if not exists
			if (self.lastIntersecting[zombieId] === undefined) {
				self.lastIntersecting[zombieId] = false;
			}
			var currentIntersecting = self.intersects(zombie);
			// Check if zombie just started intersecting
			if (!self.lastIntersecting[zombieId] && currentIntersecting) {
				// Damage zombie
				zombie.takeDamage();
				// Take damage to barrier
				self.health -= 5;
				// Update barrier appearance based on health
				var healthPercent = self.health / self.maxHealth;
				if (healthPercent > 0.7) {
					barrierGraphics.tint = 0x8B4513; // Brown
				} else if (healthPercent > 0.4) {
					barrierGraphics.tint = 0xFF8C00; // Orange
				} else {
					barrierGraphics.tint = 0xFF0000; // Red
				}
				// Destroy barrier if health reaches 0
				if (self.health <= 0) {
					self.destroy();
					var index = barriers.indexOf(self);
					if (index > -1) {
						barriers.splice(index, 1);
					}
					return;
				}
			}
			// Update last intersecting state
			self.lastIntersecting[zombieId] = currentIntersecting;
		}
	};
	return self;
});
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletGraphics = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 8;
	self.target = null;
	self.update = function () {
		if (!self.target || zombies.indexOf(self.target) === -1) {
			self.destroy();
			var index = bullets.indexOf(self);
			if (index > -1) {
				bullets.splice(index, 1);
			}
			return;
		}
		// Move toward target
		var dx = self.target.x - self.x;
		var dy = self.target.y - self.y;
		var distance = Math.sqrt(dx * dx + dy * dy);
		if (distance < 10) {
			// Hit target
			self.target.takeDamage();
			self.destroy();
			var index = bullets.indexOf(self);
			if (index > -1) {
				bullets.splice(index, 1);
			}
		} else {
			self.x += dx / distance * self.speed;
			self.y += dy / distance * self.speed;
		}
	};
	return self;
});
var Tower = Container.expand(function () {
	var self = Container.call(this);
	var towerGraphics = self.attachAsset('tower', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.range = 150;
	self.shootCooldown = 0;
	self.shootRate = 30; // frames between shots
	self.level = 1;
	self.update = function () {
		if (self.shootCooldown > 0) {
			self.shootCooldown--;
			return;
		}
		// Find nearest zombie in range
		var nearestZombie = null;
		var nearestDistance = Infinity;
		for (var i = 0; i < zombies.length; i++) {
			var zombie = zombies[i];
			var dx = zombie.x - self.x;
			var dy = zombie.y - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance <= self.range && distance < nearestDistance) {
				nearestDistance = distance;
				nearestZombie = zombie;
			}
		}
		if (nearestZombie) {
			self.shoot(nearestZombie);
			self.shootCooldown = self.shootRate;
		}
	};
	self.shoot = function (target) {
		var bullet = new Bullet();
		bullet.x = self.x;
		bullet.y = self.y;
		bullet.target = target;
		bullets.push(bullet);
		game.addChild(bullet);
		LK.getSound('shoot').play();
	};
	self.upgrade = function () {
		if (gamePoints >= self.getUpgradeCost()) {
			gamePoints -= self.getUpgradeCost();
			self.level++;
			self.range += 20;
			self.shootRate = Math.max(10, self.shootRate - 5);
			towerGraphics.tint = 0x2e7d32; // Green tint for upgraded towers
			updateUI();
		}
	};
	self.getUpgradeCost = function () {
		return self.level * 15;
	};
	return self;
});
var Zombie = Container.expand(function () {
	var self = Container.call(this);
	var zombieGraphics = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 1;
	self.health = 1;
	self.targetX = cityCenter.x;
	self.targetY = cityCenter.y;
	self.update = function () {
		// Move toward city center
		var dx = self.targetX - self.x;
		var dy = self.targetY - self.y;
		var distance = Math.sqrt(dx * dx + dy * dy);
		if (distance > 5) {
			self.x += dx / distance * self.speed;
			self.y += dy / distance * self.speed;
		}
	};
	self.takeDamage = function () {
		self.health--;
		if (self.health <= 0) {
			self.die();
		}
	};
	self.die = function () {
		LK.getSound('zombieHit').play();
		gamePoints += 5;
		updateUI();
		// Remove from zombies array
		var index = zombies.indexOf(self);
		if (index > -1) {
			zombies.splice(index, 1);
		}
		self.destroy();
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x2e2e2e
});

/**** 
* Game Code
****/ 
// Game variables
var towers = [];
var zombies = [];
var bullets = [];
var barriers = [];
var gamePoints = 50;
var wave = 1;
var zombiesSpawned = 0;
var zombiesToSpawn = 5;
var spawnTimer = 0;
var waveComplete = true;
var gridSize = 80;
var towerCost = 20;
var barrierCost = 30;
// Create city center
var cityCenter = game.addChild(LK.getAsset('cityCenter', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 1024,
	y: 1366
}));
// Create UI elements
var pointsText = new Text2('Points: 50', {
	size: 60,
	fill: 0xFFFFFF
});
pointsText.anchor.set(0, 0);
LK.gui.topRight.addChild(pointsText);
var waveText = new Text2('Wave: 1', {
	size: 60,
	fill: 0xFFFFFF
});
waveText.anchor.set(0.5, 0);
LK.gui.top.addChild(waveText);
var instructionText = new Text2('Tap: Tower (20) | Hold: Barrier (30)', {
	size: 40,
	fill: 0xFFFFFF
});
instructionText.anchor.set(0.5, 1);
LK.gui.bottom.addChild(instructionText);
function updateUI() {
	pointsText.setText('Points: ' + gamePoints);
	waveText.setText('Wave: ' + wave);
}
function snapToGrid(value) {
	return Math.floor(value / gridSize) * gridSize + gridSize / 2;
}
function canPlaceTower(x, y) {
	// Check if position is too close to city center
	var dx = x - cityCenter.x;
	var dy = y - cityCenter.y;
	var distanceToCenter = Math.sqrt(dx * dx + dy * dy);
	if (distanceToCenter < 150) {
		return false;
	}
	// Check if there's already a tower at this position
	for (var i = 0; i < towers.length; i++) {
		var tower = towers[i];
		if (Math.abs(tower.x - x) < gridSize / 2 && Math.abs(tower.y - y) < gridSize / 2) {
			return false;
		}
	}
	// Check if there's already a barrier at this position
	for (var i = 0; i < barriers.length; i++) {
		var barrier = barriers[i];
		if (Math.abs(barrier.x - x) < gridSize / 2 && Math.abs(barrier.y - y) < gridSize / 2) {
			return false;
		}
	}
	return true;
}
function placeTower(x, y) {
	if (gamePoints >= towerCost && canPlaceTower(x, y)) {
		var tower = new Tower();
		tower.x = x;
		tower.y = y;
		towers.push(tower);
		game.addChild(tower);
		gamePoints -= towerCost;
		updateUI();
	}
}
function placeBarrier(x, y) {
	if (gamePoints >= barrierCost && canPlaceTower(x, y)) {
		var barrier = new Barrier();
		barrier.x = x;
		barrier.y = y;
		barriers.push(barrier);
		game.addChild(barrier);
		gamePoints -= barrierCost;
		updateUI();
	}
}
function getTowerAt(x, y) {
	for (var i = 0; i < towers.length; i++) {
		var tower = towers[i];
		var dx = Math.abs(tower.x - x);
		var dy = Math.abs(tower.y - y);
		if (dx < gridSize / 2 && dy < gridSize / 2) {
			return tower;
		}
	}
	return null;
}
function spawnZombie() {
	var zombie = new Zombie();
	// Spawn from random edge
	var edge = Math.floor(Math.random() * 4);
	switch (edge) {
		case 0:
			// Top
			zombie.x = Math.random() * 2048;
			zombie.y = 0;
			break;
		case 1:
			// Right
			zombie.x = 2048;
			zombie.y = Math.random() * 2732;
			break;
		case 2:
			// Bottom
			zombie.x = Math.random() * 2048;
			zombie.y = 2732;
			break;
		case 3:
			// Left
			zombie.x = 0;
			zombie.y = Math.random() * 2732;
			break;
	}
	// Increase speed and health with waves
	zombie.speed = 1 + (wave - 1) * 0.2;
	zombie.health = 1 + Math.floor((wave - 1) / 3);
	zombies.push(zombie);
	game.addChild(zombie);
}
function startNextWave() {
	wave++;
	zombiesToSpawn = 5 + wave * 2;
	zombiesSpawned = 0;
	waveComplete = false;
	spawnTimer = 0;
	updateUI();
}
var holdTimer = 0;
var isHolding = false;
var holdPosition = {
	x: 0,
	y: 0
};
game.down = function (x, y, obj) {
	var gridX = snapToGrid(x);
	var gridY = snapToGrid(y);
	holdPosition.x = gridX;
	holdPosition.y = gridY;
	isHolding = true;
	holdTimer = 0;
	var existingTower = getTowerAt(gridX, gridY);
	if (existingTower) {
		// Try to upgrade tower
		existingTower.upgrade();
		isHolding = false;
	}
};
game.up = function (x, y, obj) {
	if (isHolding && holdTimer < 30) {
		// Short tap - place tower
		placeTower(holdPosition.x, holdPosition.y);
	}
	isHolding = false;
	holdTimer = 0;
};
game.update = function () {
	// Handle hold timer for barrier placement
	if (isHolding) {
		holdTimer++;
		if (holdTimer >= 30) {
			// Long hold - place barrier
			placeBarrier(holdPosition.x, holdPosition.y);
			isHolding = false;
			holdTimer = 0;
		}
	}
	// Spawn zombies for current wave
	if (!waveComplete) {
		spawnTimer++;
		if (spawnTimer >= 60 && zombiesSpawned < zombiesToSpawn) {
			// Spawn every second
			spawnZombie();
			zombiesSpawned++;
			spawnTimer = 0;
		}
		if (zombiesSpawned >= zombiesToSpawn && zombies.length === 0) {
			waveComplete = true;
			LK.setTimeout(startNextWave, 2000); // Start next wave after 2 seconds
		}
	}
	// Check if zombies reached city center
	for (var i = zombies.length - 1; i >= 0; i--) {
		var zombie = zombies[i];
		var dx = zombie.x - cityCenter.x;
		var dy = zombie.y - cityCenter.y;
		var distance = Math.sqrt(dx * dx + dy * dy);
		if (distance < 100) {
			// Game over
			LK.showGameOver();
			return;
		}
	}
	// Update all towers (this enables shooting)
	for (var i = 0; i < towers.length; i++) {
		towers[i].update();
	}
	// Update all barriers (this enables damage dealing)
	for (var i = 0; i < barriers.length; i++) {
		barriers[i].update();
	}
	// Update score
	LK.setScore(gamePoints + (wave - 1) * 100);
};
// Start first wave after 3 seconds
LK.setTimeout(startNextWave, 3000);

===================================================================
--- original.js
+++ change.js
@@ -5,8 +5,59 @@
 
 /**** 
 * Classes
 ****/ 
+var Barrier = Container.expand(function () {
+	var self = Container.call(this);
+	var barrierGraphics = self.attachAsset('tower', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	barrierGraphics.tint = 0x8B4513; // Brown tint for barriers
+	self.health = 100; // Very high resistance
+	self.maxHealth = 100;
+	self.lastIntersecting = {};
+	self.update = function () {
+		// Check collision with zombies
+		for (var i = 0; i < zombies.length; i++) {
+			var zombie = zombies[i];
+			var zombieId = zombies.indexOf(zombie);
+			// Initialize last intersecting state if not exists
+			if (self.lastIntersecting[zombieId] === undefined) {
+				self.lastIntersecting[zombieId] = false;
+			}
+			var currentIntersecting = self.intersects(zombie);
+			// Check if zombie just started intersecting
+			if (!self.lastIntersecting[zombieId] && currentIntersecting) {
+				// Damage zombie
+				zombie.takeDamage();
+				// Take damage to barrier
+				self.health -= 5;
+				// Update barrier appearance based on health
+				var healthPercent = self.health / self.maxHealth;
+				if (healthPercent > 0.7) {
+					barrierGraphics.tint = 0x8B4513; // Brown
+				} else if (healthPercent > 0.4) {
+					barrierGraphics.tint = 0xFF8C00; // Orange
+				} else {
+					barrierGraphics.tint = 0xFF0000; // Red
+				}
+				// Destroy barrier if health reaches 0
+				if (self.health <= 0) {
+					self.destroy();
+					var index = barriers.indexOf(self);
+					if (index > -1) {
+						barriers.splice(index, 1);
+					}
+					return;
+				}
+			}
+			// Update last intersecting state
+			self.lastIntersecting[zombieId] = currentIntersecting;
+		}
+	};
+	return self;
+});
 var Bullet = Container.expand(function () {
 	var self = Container.call(this);
 	var bulletGraphics = self.attachAsset('bullet', {
 		anchorX: 0.5,
@@ -152,16 +203,18 @@
 // Game variables
 var towers = [];
 var zombies = [];
 var bullets = [];
+var barriers = [];
 var gamePoints = 50;
 var wave = 1;
 var zombiesSpawned = 0;
 var zombiesToSpawn = 5;
 var spawnTimer = 0;
 var waveComplete = true;
 var gridSize = 80;
 var towerCost = 20;
+var barrierCost = 30;
 // Create city center
 var cityCenter = game.addChild(LK.getAsset('cityCenter', {
 	anchorX: 0.5,
 	anchorY: 0.5,
@@ -180,9 +233,9 @@
 	fill: 0xFFFFFF
 });
 waveText.anchor.set(0.5, 0);
 LK.gui.top.addChild(waveText);
-var instructionText = new Text2('Tap to place tower (Cost: 20)', {
+var instructionText = new Text2('Tap: Tower (20) | Hold: Barrier (30)', {
 	size: 40,
 	fill: 0xFFFFFF
 });
 instructionText.anchor.set(0.5, 1);
@@ -208,8 +261,15 @@
 		if (Math.abs(tower.x - x) < gridSize / 2 && Math.abs(tower.y - y) < gridSize / 2) {
 			return false;
 		}
 	}
+	// Check if there's already a barrier at this position
+	for (var i = 0; i < barriers.length; i++) {
+		var barrier = barriers[i];
+		if (Math.abs(barrier.x - x) < gridSize / 2 && Math.abs(barrier.y - y) < gridSize / 2) {
+			return false;
+		}
+	}
 	return true;
 }
 function placeTower(x, y) {
 	if (gamePoints >= towerCost && canPlaceTower(x, y)) {
@@ -221,8 +281,19 @@
 		gamePoints -= towerCost;
 		updateUI();
 	}
 }
+function placeBarrier(x, y) {
+	if (gamePoints >= barrierCost && canPlaceTower(x, y)) {
+		var barrier = new Barrier();
+		barrier.x = x;
+		barrier.y = y;
+		barriers.push(barrier);
+		game.addChild(barrier);
+		gamePoints -= barrierCost;
+		updateUI();
+	}
+}
 function getTowerAt(x, y) {
 	for (var i = 0; i < towers.length; i++) {
 		var tower = towers[i];
 		var dx = Math.abs(tower.x - x);
@@ -272,21 +343,47 @@
 	waveComplete = false;
 	spawnTimer = 0;
 	updateUI();
 }
+var holdTimer = 0;
+var isHolding = false;
+var holdPosition = {
+	x: 0,
+	y: 0
+};
 game.down = function (x, y, obj) {
 	var gridX = snapToGrid(x);
 	var gridY = snapToGrid(y);
+	holdPosition.x = gridX;
+	holdPosition.y = gridY;
+	isHolding = true;
+	holdTimer = 0;
 	var existingTower = getTowerAt(gridX, gridY);
 	if (existingTower) {
 		// Try to upgrade tower
 		existingTower.upgrade();
-	} else {
-		// Try to place new tower
-		placeTower(gridX, gridY);
+		isHolding = false;
 	}
 };
+game.up = function (x, y, obj) {
+	if (isHolding && holdTimer < 30) {
+		// Short tap - place tower
+		placeTower(holdPosition.x, holdPosition.y);
+	}
+	isHolding = false;
+	holdTimer = 0;
+};
 game.update = function () {
+	// Handle hold timer for barrier placement
+	if (isHolding) {
+		holdTimer++;
+		if (holdTimer >= 30) {
+			// Long hold - place barrier
+			placeBarrier(holdPosition.x, holdPosition.y);
+			isHolding = false;
+			holdTimer = 0;
+		}
+	}
 	// Spawn zombies for current wave
 	if (!waveComplete) {
 		spawnTimer++;
 		if (spawnTimer >= 60 && zombiesSpawned < zombiesToSpawn) {
@@ -315,8 +412,12 @@
 	// Update all towers (this enables shooting)
 	for (var i = 0; i < towers.length; i++) {
 		towers[i].update();
 	}
+	// Update all barriers (this enables damage dealing)
+	for (var i = 0; i < barriers.length; i++) {
+		barriers[i].update();
+	}
 	// Update score
 	LK.setScore(gamePoints + (wave - 1) * 100);
 };
 // Start first wave after 3 seconds