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

/**** 
* Classes
****/ 
// Bullet fired by soldiers
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	var bulletAsset = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 16;
	self.target = null; // Zombie instance
	self.damage = 1;
	self.update = function () {
		if (!self.target || self.target.isDead) {
			self.destroy();
			return;
		}
		// Move towards target
		var dx = self.target.x - self.x;
		var dy = self.target.y - self.y;
		var dist = Math.sqrt(dx * dx + dy * dy);
		if (dist < 32) {
			// Hit!
			self.target.takeDamage(self.damage);
			self.destroy();
			return;
		}
		var step = self.speed;
		self.x += dx / dist * step;
		self.y += dy / dist * step;
	};
	return self;
});
// Fireball projectile thrown by FireballZombie
var Fireball = Container.expand(function () {
	var self = Container.call(this);
	var fbAsset = self.attachAsset('bullet', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	fbAsset.tint = 0xFF6600;
	self.targetX = 0;
	self.targetY = 0;
	self.speed = 18;
	self.update = function () {
		var dx = self.targetX - self.x;
		var dy = self.targetY - self.y;
		var dist = Math.sqrt(dx * dx + dy * dy);
		if (dist < 32) {
			// Hit gate!
			game.gateHp--;
			LK.effects.flashObject(game.castleGate, 0xFF6600, 400);
			if (game.gateHp <= 0) {
				LK.effects.flashScreen(0xFF0000, 1000);
				LK.showGameOver();
			}
			self.destroy();
			return;
		}
		var step = self.speed;
		self.x += dx / dist * step;
		self.y += dy / dist * step;
	};
	return self;
});
// FireballZombie: throws fireballs at the castle gate after 20s
var FireballZombie = Container.expand(function () {
	var self = Container.call(this);
	var zombieAsset = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.maxHp = 3;
	self.hp = self.maxHp;
	self.speed = (1.2 + Math.random() * 1.2) / 2;
	self.isDead = false;
	self.targetX = 0;
	self.targetY = 0;
	self.fireballCooldown = 90 + Math.floor(Math.random() * 60); // 1.5s-2.5s
	self.lastFireballTick = 0;
	self.takeDamage = function (dmg) {
		if (self.isDead) return;
		self.hp -= dmg;
		if (self.hp <= 0) {
			self.die();
		} else {
			tween(self, {
				tint: 0xFF6600
			}, {
				duration: 80,
				onFinish: function onFinish() {
					tween(self, {
						tint: 0x4CAF50
					}, {
						duration: 120
					});
				}
			});
		}
	};
	self.die = function () {
		if (self.isDead) return;
		self.isDead = true;
		LK.getSound('zombieDie').play();
		game.gold += 2;
		updateGoldText();
		tween(self, {
			alpha: 0
		}, {
			duration: 200,
			onFinish: function onFinish() {
				self.destroy();
			}
		});
	};
	self.update = function () {
		if (self.isDead) return;
		// Find the wall segment this zombie is closest to (the wall between two towers)
		var closestWall = null;
		var minWallDist = 99999;
		for (var i = 0; i < walls.length; i++) {
			var wall = walls[i];
			if (wall.isDestroyed) continue;
			var dxw = wall.x - self.x;
			var dyw = wall.y - self.y;
			var dWall = Math.sqrt(dxw * dxw + dyw * dyw);
			if (dWall < minWallDist) {
				minWallDist = dWall;
				closestWall = wall;
			}
		}
		// If there is a wall in the way, attack it first
		if (closestWall && minWallDist < closestWall.width / 2 + 40) {
			self.attackTimer = self.attackTimer || 0;
			self.attackTimer--;
			if (self.attackTimer <= 0) {
				closestWall.takeDamage(1);
				tween(self, {
					scaleX: 1.15,
					scaleY: 0.85
				}, {
					duration: 60,
					onFinish: function onFinish() {
						tween(self, {
							scaleX: 1,
							scaleY: 1
						}, {
							duration: 60
						});
					}
				});
				self.attackTimer = 40;
			}
			return;
		}
		// Fireball attack if in range of gate (distance < 500)
		var dxGate = game.castleGate.x - self.x;
		var dyGate = game.castleGate.y - self.y;
		var distGate = Math.sqrt(dxGate * dxGate + dyGate * dyGate);
		if (distGate < 500) {
			self.fireballCooldown--;
			if (self.fireballCooldown <= 0) {
				// Throw fireball at gate
				var fb = new Fireball();
				fb.x = self.x;
				fb.y = self.y;
				fb.targetX = game.castleGate.x;
				fb.targetY = game.castleGate.y;
				fireballs.push(fb);
				game.addChild(fb);
				self.fireballCooldown = 90 + Math.floor(Math.random() * 60);
			}
		}
		// Move toward the gate
		var dx = self.targetX - self.x;
		var dy = self.targetY - self.y;
		var dist = Math.sqrt(dx * dx + dy * dy);
		if (dist < 30) {
			self.isDead = true;
			self.destroy();
			game.gateHp--;
			LK.effects.flashObject(game.castleGate, 0xFF6600, 400);
			if (game.gateHp <= 0) {
				LK.effects.flashScreen(0xFF0000, 1000);
				LK.showGameOver();
			}
			return;
		}
		var step = self.speed;
		self.x += dx / dist * step;
		self.y += dy / dist * step;
	};
	return self;
});
// Gold coin dropped by zombies
var Gold = Container.expand(function () {
	var self = Container.call(this);
	var goldAsset = self.attachAsset('gold', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.value = 1;
	self.life = 180; // 3 seconds
	self.update = function () {
		self.life--;
		if (self.life <= 0) {
			self.destroy();
		}
	};
	return self;
});
// Zombie that shoots bullets at the castle gate after 20s
var ShooterZombie = Container.expand(function () {
	var self = Container.call(this);
	var zombieAsset = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.maxHp = 2;
	self.hp = self.maxHp;
	self.speed = (1.2 + Math.random() * 1.2) / 2;
	self.isDead = false;
	self.targetX = 0;
	self.targetY = 0;
	self.bulletCooldown = 70 + Math.floor(Math.random() * 40); // 1.2s-1.8s
	self.lastBulletTick = 0;
	self.takeDamage = function (dmg) {
		if (self.isDead) return;
		self.hp -= dmg;
		if (self.hp <= 0) {
			self.die();
		} else {
			tween(self, {
				tint: 0x99CCFF
			}, {
				duration: 80,
				onFinish: function onFinish() {
					tween(self, {
						tint: 0x4CAF50
					}, {
						duration: 120
					});
				}
			});
		}
	};
	self.die = function () {
		if (self.isDead) return;
		self.isDead = true;
		LK.getSound('zombieDie').play();
		game.gold += 2;
		updateGoldText();
		tween(self, {
			alpha: 0
		}, {
			duration: 200,
			onFinish: function onFinish() {
				self.destroy();
			}
		});
	};
	self.update = function () {
		if (self.isDead) return;
		// Find the wall segment this zombie is closest to
		var closestWall = null;
		var minWallDist = 99999;
		for (var i = 0; i < walls.length; i++) {
			var wall = walls[i];
			if (wall.isDestroyed) continue;
			var dxw = wall.x - self.x;
			var dyw = wall.y - self.y;
			var dWall = Math.sqrt(dxw * dxw + dyw * dyw);
			if (dWall < minWallDist) {
				minWallDist = dWall;
				closestWall = wall;
			}
		}
		// If there is a wall in the way, attack it first
		if (closestWall && minWallDist < closestWall.width / 2 + 40) {
			self.attackTimer = self.attackTimer || 0;
			self.attackTimer--;
			if (self.attackTimer <= 0) {
				closestWall.takeDamage(1);
				tween(self, {
					scaleX: 1.15,
					scaleY: 0.85
				}, {
					duration: 60,
					onFinish: function onFinish() {
						tween(self, {
							scaleX: 1,
							scaleY: 1
						}, {
							duration: 60
						});
					}
				});
				self.attackTimer = 40;
			}
			return;
		}
		// Bullet attack if in range of gate (distance < 500)
		var dxGate = game.castleGate.x - self.x;
		var dyGate = game.castleGate.y - self.y;
		var distGate = Math.sqrt(dxGate * dxGate + dyGate * dyGate);
		if (distGate < 500) {
			self.bulletCooldown--;
			if (self.bulletCooldown <= 0) {
				// Shoot bullet at gate
				var bullet = new Bullet();
				bullet.x = self.x;
				bullet.y = self.y;
				bullet.target = {
					x: game.castleGate.x,
					y: game.castleGate.y,
					isDead: false,
					takeDamage: function takeDamage() {
						game.gateHp--;
						LK.effects.flashObject(game.castleGate, 0x99CCFF, 400);
						if (game.gateHp <= 0) {
							LK.effects.flashScreen(0xFF0000, 1000);
							LK.showGameOver();
						}
					}
				};
				bullet.damage = 1;
				bullets.push(bullet);
				game.addChild(bullet);
				self.bulletCooldown = 70 + Math.floor(Math.random() * 40);
			}
		}
		// Move toward the gate
		var dx = self.targetX - self.x;
		var dy = self.targetY - self.y;
		var dist = Math.sqrt(dx * dx + dy * dy);
		if (dist < 30) {
			self.isDead = true;
			self.destroy();
			game.gateHp--;
			LK.effects.flashObject(game.castleGate, 0x99CCFF, 400);
			if (game.gateHp <= 0) {
				LK.effects.flashScreen(0xFF0000, 1000);
				LK.showGameOver();
			}
			return;
		}
		var step = self.speed;
		self.x += dx / dist * step;
		self.y += dy / dist * step;
	};
	return self;
});
// Soldier on a watchtower
var Soldier = Container.expand(function () {
	var self = Container.call(this);
	var soldierAsset = self.attachAsset('soldier', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.level = 1;
	self.fireRate = 60; // frames between shots
	self.fireTimer = 0;
	self.range = 600;
	self.upgradeCost = 5;
	self.parentTower = null;
	self.update = function () {
		if (!self.parentTower) return;
		self.fireTimer--;
		if (self.fireTimer <= 0) {
			// Find nearest zombie in range
			var nearest = null;
			var minDist = self.range;
			for (var i = 0; i < zombies.length; i++) {
				var z = zombies[i];
				if (z.isDead) continue;
				var dx = z.x - self.x;
				var dy = z.y - self.y;
				var dist = Math.sqrt(dx * dx + dy * dy);
				if (dist < minDist) {
					minDist = dist;
					nearest = z;
				}
			}
			if (nearest) {
				// Fire!
				var bullet = new Bullet();
				bullet.x = self.x;
				bullet.y = self.y;
				bullet.target = nearest;
				bullet.damage = self.level;
				bullets.push(bullet);
				game.addChild(bullet);
				LK.getSound('shoot').play();
				self.fireTimer = Math.max(20, self.fireRate - self.level * 8);
			}
		}
	};
	self.upgrade = function () {
		self.level++;
		self.fireRate = Math.max(20, self.fireRate - 8);
		self.upgradeCost += 5;
		// Animate upgrade
		tween(self, {
			scaleX: 1.2,
			scaleY: 1.2
		}, {
			duration: 120,
			onFinish: function onFinish() {
				tween(self, {
					scaleX: 1,
					scaleY: 1
				}, {
					duration: 120
				});
			}
		});
	};
	return self;
});
// Wall between towers
var Wall = Container.expand(function () {
	var self = Container.call(this);
	// Use a simple box shape for the wall
	var wallAsset = self.attachAsset('wall', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.maxHp = 50;
	self.hp = self.maxHp;
	self.indexA = 0; // index of first tower
	self.indexB = 0; // index of second tower
	self.isDestroyed = false;
	self.takeDamage = function (dmg) {
		if (self.isDestroyed) return;
		self.hp -= dmg;
		if (self.hp <= 0) {
			self.hp = 0;
			self.isDestroyed = true;
			// Animate wall breaking
			tween(self, {
				alpha: 0
			}, {
				duration: 300,
				onFinish: function onFinish() {
					self.visible = false;
				}
			});
		} else {
			// Flash red
			tween(self, {
				tint: 0xFF0000
			}, {
				duration: 80,
				onFinish: function onFinish() {
					tween(self, {
						tint: 0xCCCCCC
					}, {
						duration: 120
					});
				}
			});
		}
	};
	self.repair = function () {
		self.hp = self.maxHp;
		self.isDestroyed = false;
		self.visible = true;
		self.alpha = 1;
		self.tint = 0xCCCCCC;
	};
	return self;
});
// Watchtower (can have a soldier)
var Watchtower = Container.expand(function () {
	var self = Container.call(this);
	var towerAsset = self.attachAsset('watchtower', {
		anchorX: 0.5,
		anchorY: 1
	});
	self.soldier = null;
	self.index = 0;
	// For tap detection
	self.down = function (x, y, obj) {
		if (!self.soldier) {
			// Recruit soldier if enough gold (5)
			if (game.gold >= 5) {
				game.gold -= 5;
				var s = new Soldier();
				s.x = self.x;
				s.y = self.y - 80;
				s.parentTower = self;
				self.soldier = s;
				soldiers.push(s);
				game.addChild(s);
				updateGoldText();
				// Animate
				tween(s, {
					alpha: 0
				}, {
					duration: 0,
					onFinish: function onFinish() {
						tween(s, {
							alpha: 1
						}, {
							duration: 200
						});
					}
				});
			}
		} else {
			// Upgrade soldier
			if (game.gold >= self.soldier.upgradeCost) {
				game.gold -= self.soldier.upgradeCost;
				self.soldier.upgrade();
				updateGoldText();
			}
		}
	};
	return self;
});
// Zombie enemy
var Zombie = Container.expand(function () {
	var self = Container.call(this);
	var zombieAsset = self.attachAsset('zombie', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.maxHp = 2;
	self.hp = self.maxHp;
	self.speed = (2 + Math.random() * 1.5) / 2;
	self.isDead = false;
	self.targetX = 0;
	self.targetY = 0;
	self.takeDamage = function (dmg) {
		if (self.isDead) return;
		self.hp -= dmg;
		if (self.hp <= 0) {
			self.die();
		} else {
			// Flash red
			tween(self, {
				tint: 0xFF0000
			}, {
				duration: 80,
				onFinish: function onFinish() {
					tween(self, {
						tint: 0x4CAF50
					}, {
						duration: 120
					});
				}
			});
		}
	};
	self.die = function () {
		if (self.isDead) return;
		self.isDead = true;
		LK.getSound('zombieDie').play();
		// Instantly collect gold
		game.gold += 1;
		updateGoldText();
		// Animate fade out
		tween(self, {
			alpha: 0
		}, {
			duration: 200,
			onFinish: function onFinish() {
				self.destroy();
			}
		});
	};
	self.update = function () {
		if (self.isDead) return;
		// Find the wall segment this zombie is closest to (the wall between two towers)
		var closestWall = null;
		var minWallDist = 99999;
		for (var i = 0; i < walls.length; i++) {
			var wall = walls[i];
			// Only consider walls that are not destroyed
			if (wall.isDestroyed) continue;
			// Distance from zombie to wall center
			var dxw = wall.x - self.x;
			var dyw = wall.y - self.y;
			var dWall = Math.sqrt(dxw * dxw + dyw * dyw);
			if (dWall < minWallDist) {
				minWallDist = dWall;
				closestWall = wall;
			}
		}
		// If there is a wall in the way, attack it first
		if (closestWall && minWallDist < closestWall.width / 2 + 40) {
			// Attack wall
			self.attackTimer = self.attackTimer || 0;
			self.attackTimer--;
			if (self.attackTimer <= 0) {
				closestWall.takeDamage(1);
				// Animate zombie attack
				tween(self, {
					scaleX: 1.15,
					scaleY: 0.85
				}, {
					duration: 60,
					onFinish: function onFinish() {
						tween(self, {
							scaleX: 1,
							scaleY: 1
						}, {
							duration: 60
						});
					}
				});
				self.attackTimer = 40;
			}
			// Don't move through the wall
			return;
		}
		// If no wall blocks the way, move toward the gate
		var dx = self.targetX - self.x;
		var dy = self.targetY - self.y;
		var dist = Math.sqrt(dx * dx + dy * dy);
		if (dist < 30) {
			// Reached gate
			self.isDead = true;
			self.destroy();
			// Damage gate
			game.gateHp--;
			LK.effects.flashObject(game.castleGate, 0xFF0000, 400);
			if (game.gateHp <= 0) {
				LK.effects.flashScreen(0xFF0000, 1000);
				LK.showGameOver();
			}
			return;
		}
		var step = self.speed;
		self.x += dx / dist * step;
		self.y += dy / dist * step;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x222233
});

/**** 
* Game Code
****/ 
// Music
// Sound for zombie death
// Sound for collecting gold
// Sound for shooting
// Gold coin
// Bullet
// Zombie
// Soldier
// Watchtower base
// Castle gate (center bottom)
// Play music
LK.playMusic('castleTheme');
// Game variables
var zombies = [];
var bullets = [];
var golds = [];
var soldiers = [];
var towers = [];
var fireballs = [];
game.gateHp = 5;
game.gold = 10;
game.wave = 1;
game.waveTimer = 0;
// Arrange towers in a regular octagon shape and center the gate at the bottom
var octCenterX = 1024;
var octCenterY = 1400;
var octRadius = 700;
var numTowers = 8;
var towerPositions = [];
for (var i = 0; i < numTowers; i++) {
	// Octagon: 8 points, 360/8 = 45deg per point, start at -45deg (rotated 45deg from top)
	var angle = -Math.PI / 4 + i * (2 * Math.PI / numTowers);
	var x = octCenterX + Math.cos(angle) * octRadius;
	var y = octCenterY + Math.sin(angle) * octRadius;
	towerPositions.push({
		x: x,
		y: y
	});
}
// Place walls between each pair of adjacent towers
var walls = [];
for (var i = 0; i < numTowers; i++) {
	var a = towerPositions[i];
	var b = towerPositions[(i + 1) % numTowers];
	var wall = new Wall();
	wall.indexA = i;
	wall.indexB = (i + 1) % numTowers;
	// Position wall at midpoint between towers
	wall.x = (a.x + b.x) / 2;
	wall.y = (a.y + b.y) / 2;
	// Set wall rotation to match the line between towers
	var dx = b.x - a.x;
	var dy = b.y - a.y;
	wall.rotation = Math.atan2(dy, dx);
	// Set wall length to distance between towers minus some margin
	var dist = Math.sqrt(dx * dx + dy * dy);
	wall.width = dist - 40;
	wall.height = 40;
	wall.zIndex = 1;
	walls.push(wall);
	game.addChild(wall);
}
// Place the castle gate exactly at the center of the octagon
var gateX = octCenterX;
var gateY = octCenterY;
game.castleGate = LK.getAsset('castleGate', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: gateX,
	y: gateY
});
game.addChild(game.castleGate);
for (var i = 0; i < towerPositions.length; i++) {
	var pos = towerPositions[i];
	var prev = towerPositions[(i - 1 + numTowers) % numTowers];
	var next = towerPositions[(i + 1) % numTowers];
	// Find the direction from this tower to the center
	var toCenterX = octCenterX - pos.x;
	var toCenterY = octCenterY - pos.y;
	var toCenterLen = Math.sqrt(toCenterX * toCenterX + toCenterY * toCenterY);
	// The tower asset's anchor is (0.5, 1), so y is at the base.
	// Move the tower so its base is flush with the wall ends.
	// The wall thickness is 40, so offset by half the wall height (20) toward the center.
	var offset = 20;
	var adjX = pos.x + toCenterX / toCenterLen * offset;
	var adjY = pos.y + toCenterY / toCenterLen * offset;
	var tower = new Watchtower();
	tower.x = adjX;
	tower.y = adjY;
	tower.index = i;
	// Rotate each tower to face outward from the center, forming a connected octagon
	// The outward angle is the angle from the center to the tower, plus 90deg (PI/2) to align the tower's front outward
	var outwardAngle = Math.atan2(pos.y - octCenterY, pos.x - octCenterX) + Math.PI / 2;
	tower.rotation = outwardAngle;
	towers.push(tower);
	game.addChild(tower);
	// Add a number label above each tower (1-based)
	var towerNumTxt = new Text2('' + (i + 1), {
		size: 80,
		fill: 0xFFFFFF
	});
	towerNumTxt.anchor.set(0.5, 1);
	// Place the label just above the tower top (tower asset is 220px tall, anchorY=1)
	towerNumTxt.x = 0;
	towerNumTxt.y = -230;
	tower.addChild(towerNumTxt);
}
// GUI: Gold display
var goldTxt = new Text2('Gold: 10', {
	size: 90,
	fill: 0xFFD700
});
goldTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(goldTxt);
// GUI: Gate HP display
var hpTxt = new Text2('Gate: 5', {
	size: 90,
	fill: 0xFFFFFF
});
hpTxt.anchor.set(0.5, 0);
LK.gui.topRight.addChild(hpTxt);
// GUI: Wave display
var waveTxt = new Text2('Wave: 1', {
	size: 80,
	fill: 0x00BFFF
});
waveTxt.anchor.set(0.5, 0);
LK.gui.bottom.addChild(waveTxt);
// --- Zoom Controls ---
var zoomLevel = 1;
var minZoom = 0.5;
var maxZoom = 2.0;
var zoomStep = 0.2;
// Zoom In Button
var zoomInBtn = new Text2('+', {
	size: 120,
	fill: 0xFFFFFF
});
zoomInBtn.anchor.set(0.5, 0.5);
zoomInBtn.x = 1800;
zoomInBtn.y = 200;
zoomInBtn.interactive = true;
zoomInBtn.buttonMode = true;
zoomInBtn.down = function (x, y, obj) {
	if (zoomLevel < maxZoom) {
		zoomLevel += zoomStep;
		if (zoomLevel > maxZoom) zoomLevel = maxZoom;
		game.scaleX = zoomLevel;
		game.scaleY = zoomLevel;
	}
};
LK.gui.right.addChild(zoomInBtn);
// Zoom Out Button
var zoomOutBtn = new Text2('-', {
	size: 120,
	fill: 0xFFFFFF
});
zoomOutBtn.anchor.set(0.5, 0.5);
zoomOutBtn.x = 1800;
zoomOutBtn.y = 350;
zoomOutBtn.interactive = true;
zoomOutBtn.buttonMode = true;
zoomOutBtn.down = function (x, y, obj) {
	if (zoomLevel > minZoom) {
		zoomLevel -= zoomStep;
		if (zoomLevel < minZoom) zoomLevel = minZoom;
		game.scaleX = zoomLevel;
		game.scaleY = zoomLevel;
	}
};
LK.gui.right.addChild(zoomOutBtn);
function updateGoldText() {
	goldTxt.setText('Gold: ' + game.gold);
}
function updateHpText() {
	hpTxt.setText('Gate: ' + game.gateHp);
}
function updateWaveText() {
	waveTxt.setText('Wave: ' + game.wave);
}
// Handle buying soldiers/upgrades
game.down = function (x, y, obj) {
	// Check if a tower was tapped
	for (var j = 0; j < towers.length; j++) {
		var t = towers[j];
		var tx = t.x,
			ty = t.y;
		if (x > tx - 60 && x < tx + 60 && y > ty - 220 && y < ty) {
			t.down(x, y, obj);
			return;
		}
	}
};
// Main update loop
game.update = function () {
	// Update gate HP and gold
	updateHpText();
	// Track zombie kills for extra spawn
	if (typeof game.zombieKillCount === "undefined") {
		game.zombieKillCount = 0;
		game.extraZombieSpawned = false;
	}
	// Update all zombies
	for (var i = zombies.length - 1; i >= 0; i--) {
		var z = zombies[i];
		z.update();
		if (z.isDead && z.alpha === 0) {
			z.destroy();
			zombies.splice(i, 1);
			// Count zombie kills
			game.zombieKillCount++;
			// After 2 kills, spawn an extra Zombie (only once)
			if (game.zombieKillCount === 2 && !game.extraZombieSpawned) {
				var extraZ = new Zombie();
				// Spawn from random edge
				var edge = Math.floor(Math.random() * 4);
				var zx, zy;
				if (edge === 0) {
					zx = -60;
					zy = 1000 + Math.random() * 1200;
				} else if (edge === 1) {
					zx = 2048 + 60;
					zy = 1000 + Math.random() * 1200;
				} else if (edge === 2) {
					zx = 400 + Math.random() * 1200;
					zy = -80;
				} else {
					zx = 400 + Math.random() * 1200;
					zy = 2732 + 80;
				}
				extraZ.x = zx;
				extraZ.y = zy;
				extraZ.targetX = game.castleGate.x;
				extraZ.targetY = game.castleGate.y;
				extraZ.maxHp = 2 + Math.floor(game.wave / 2);
				extraZ.hp = extraZ.maxHp;
				extraZ.speed = (1 + Math.random() * 0.7 + game.wave * 0.07) / 2;
				zombies.push(extraZ);
				game.addChild(extraZ);
				game.extraZombieSpawned = true;
			}
		}
	}
	// Update all bullets
	for (var i = bullets.length - 1; i >= 0; i--) {
		var b = bullets[i];
		b.update();
		if (b.destroyed) {
			bullets.splice(i, 1);
		}
	}
	// Update all golds
	for (var i = golds.length - 1; i >= 0; i--) {
		var g = golds[i];
		g.update();
		if (g.life <= 0 || g.destroyed) {
			g.destroy();
			golds.splice(i, 1);
		}
	}
	// Update all fireballs
	for (var i = fireballs.length - 1; i >= 0; i--) {
		var fb = fireballs[i];
		fb.update();
		if (fb.destroyed) {
			fireballs.splice(i, 1);
		}
	}
	// Update all soldiers
	for (var i = 0; i < soldiers.length; i++) {
		soldiers[i].update();
	}
	// Spawn new wave every 180 ticks (3 seconds)
	game.waveTimer++;
	if (game.waveTimer >= 180) {
		game.waveTimer = 0;
		spawnWave();
	}
};
function spawnWave() {
	var n = 2 + Math.floor(game.wave * 0.7);
	for (var i = 0; i < n; i++) {
		// After 20 seconds (1200 ticks), spawn FireballZombies or ShooterZombies with 30% chance each
		var useFireballZombie = LK.ticks >= 1200 && Math.random() < 0.3;
		var useShooterZombie = !useFireballZombie && LK.ticks >= 1200 && Math.random() < 0.3;
		var z;
		if (useFireballZombie) {
			z = new FireballZombie();
		} else if (useShooterZombie) {
			z = new ShooterZombie();
		} else {
			z = new Zombie();
		}
		// Spawn from random edge
		var edge = Math.floor(Math.random() * 4);
		var zx, zy;
		if (edge === 0) {
			// left
			zx = -60;
			zy = 1000 + Math.random() * 1200;
		} else if (edge === 1) {
			// right
			zx = 2048 + 60;
			zy = 1000 + Math.random() * 1200;
		} else if (edge === 2) {
			// top
			zx = 400 + Math.random() * 1200;
			zy = -80;
		} else {
			// bottom (rare)
			zx = 400 + Math.random() * 1200;
			zy = 2732 + 80;
		}
		z.x = zx;
		z.y = zy;
		// Gate is at the middle of the basket (centered between lowest towers)
		z.targetX = game.castleGate.x;
		z.targetY = game.castleGate.y;
		// Decrease zombie speed (slower base, slower scaling)
		z.maxHp = 2 + Math.floor(game.wave / 2);
		z.hp = z.maxHp;
		z.speed = (1 + Math.random() * 0.7 + game.wave * 0.07) / 2;
		zombies.push(z);
		game.addChild(z);
	}
	game.wave++;
	updateWaveText();
}

===================================================================
--- original.js
+++ change.js
@@ -653,19 +653,19 @@
 
 /**** 
 * Game Code
 ****/ 
-// Play music
-// Castle gate (center bottom)
-// Watchtower base
-// Soldier
-// Zombie
-// Bullet
-// Gold coin
-// Sound for shooting
-// Sound for collecting gold
-// Sound for zombie death
 // Music
+// Sound for zombie death
+// Sound for collecting gold
+// Sound for shooting
+// Gold coin
+// Bullet
+// Zombie
+// Soldier
+// Watchtower base
+// Castle gate (center bottom)
+// Play music
 LK.playMusic('castleTheme');
 // Game variables
 var zombies = [];
 var bullets = [];
@@ -850,15 +850,52 @@
 // Main update loop
 game.update = function () {
 	// Update gate HP and gold
 	updateHpText();
+	// Track zombie kills for extra spawn
+	if (typeof game.zombieKillCount === "undefined") {
+		game.zombieKillCount = 0;
+		game.extraZombieSpawned = false;
+	}
 	// Update all zombies
 	for (var i = zombies.length - 1; i >= 0; i--) {
 		var z = zombies[i];
 		z.update();
 		if (z.isDead && z.alpha === 0) {
 			z.destroy();
 			zombies.splice(i, 1);
+			// Count zombie kills
+			game.zombieKillCount++;
+			// After 2 kills, spawn an extra Zombie (only once)
+			if (game.zombieKillCount === 2 && !game.extraZombieSpawned) {
+				var extraZ = new Zombie();
+				// Spawn from random edge
+				var edge = Math.floor(Math.random() * 4);
+				var zx, zy;
+				if (edge === 0) {
+					zx = -60;
+					zy = 1000 + Math.random() * 1200;
+				} else if (edge === 1) {
+					zx = 2048 + 60;
+					zy = 1000 + Math.random() * 1200;
+				} else if (edge === 2) {
+					zx = 400 + Math.random() * 1200;
+					zy = -80;
+				} else {
+					zx = 400 + Math.random() * 1200;
+					zy = 2732 + 80;
+				}
+				extraZ.x = zx;
+				extraZ.y = zy;
+				extraZ.targetX = game.castleGate.x;
+				extraZ.targetY = game.castleGate.y;
+				extraZ.maxHp = 2 + Math.floor(game.wave / 2);
+				extraZ.hp = extraZ.maxHp;
+				extraZ.speed = (1 + Math.random() * 0.7 + game.wave * 0.07) / 2;
+				zombies.push(extraZ);
+				game.addChild(extraZ);
+				game.extraZombieSpawned = true;
+			}
 		}
 	}
 	// Update all bullets
 	for (var i = bullets.length - 1; i >= 0; i--) {