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

/**** 
* Classes
****/ 
// Bullet class
var Bullet = Container.expand(function () {
	var self = Container.call(this);
	self.radius = 20;
	self.speed = 30;
	self.dir = -Math.PI / 2;
	self.damage = 1;
	self.fromPlayer = true;
	self.bulletAsset = 'bullet_basic';
	self.sprite = null;
	self.init = function (asset, speed, dir, damage, fromPlayer) {
		self.bulletAsset = asset;
		self.speed = speed;
		self.dir = dir;
		self.damage = damage;
		self.fromPlayer = fromPlayer;
		if (self.sprite) self.removeChild(self.sprite);
		self.sprite = self.attachAsset(asset, {
			anchorX: 0.5,
			anchorY: 0.5
		});
		self.radius = self.sprite.width / 2;
	};
	self.update = function () {
		self.x += Math.cos(self.dir) * self.speed;
		self.y += Math.sin(self.dir) * self.speed;
	};
	return self;
});
// Enemy class
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemySprite = self.attachAsset('enemy', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = enemySprite.width / 2;
	self.hp = 2;
	self.speed = 6 + Math.random() * 4;
	self.dir = Math.PI / 2 + (Math.random() - 0.5) * 0.5; // Downwards, slight random angle
	self.update = function () {
		self.x += Math.cos(self.dir) * self.speed;
		self.y += Math.sin(self.dir) * self.speed;
	};
	return self;
});
// GunDrop class
var GunDrop = Container.expand(function () {
	var self = Container.call(this);
	self.gun = null;
	var dropSprite = self.attachAsset('gun_drop', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = dropSprite.width / 2;
	self.setGun = function (gun) {
		self.gun = gun;
		dropSprite.tint = gun.color;
	};
	self.update = function () {
		self.y += 8;
	};
	return self;
});
// Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	var playerSprite = self.attachAsset('player', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = playerSprite.width / 2;
	self.invulnTicks = 0;
	self.flashTween = null;
	self.setInvulnerable = function (ticks) {
		self.invulnTicks = ticks;
		if (self.flashTween) tween.stop(playerSprite, {
			alpha: true
		});
		playerSprite.alpha = 0.5;
		self.flashTween = tween(playerSprite, {
			alpha: 1
		}, {
			duration: 200,
			easing: tween.linear,
			onFinish: function onFinish() {
				tween(playerSprite, {
					alpha: 0.5
				}, {
					duration: 200,
					easing: tween.linear,
					onFinish: function onFinish() {
						if (self.invulnTicks > 0) self.setInvulnerable(self.invulnTicks - 1);else playerSprite.alpha = 1;
					}
				});
			}
		});
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x181c20
});

/**** 
* Game Code
****/ 
// Game state
// Guns (shapes for now, will be replaced by images automatically)
// Sounds
// Gun definitions
var GUNS = [{
	id: 'basic',
	name: 'Basic Gun',
	bulletAsset: 'bullet_basic',
	fireRate: 18,
	// ticks between shots
	bulletSpeed: 32,
	spread: 0,
	bulletsPerShot: 1,
	damage: 1,
	color: 0xf1c40f
}, {
	id: 'spread',
	name: 'Spread Shot',
	bulletAsset: 'bullet_spread',
	fireRate: 28,
	bulletSpeed: 26,
	spread: 0.25,
	bulletsPerShot: 3,
	damage: 1,
	color: 0x8e44ad
}, {
	id: 'rapid',
	name: 'Rapid Fire',
	bulletAsset: 'bullet_rapid',
	fireRate: 7,
	bulletSpeed: 24,
	spread: 0.08,
	bulletsPerShot: 1,
	damage: 1,
	color: 0x16a085
}, {
	id: 'big',
	name: 'Big Blaster',
	bulletAsset: 'bullet_big',
	fireRate: 30,
	bulletSpeed: 20,
	spread: 0,
	bulletsPerShot: 1,
	damage: 3,
	color: 0xff9800
}];
// Helper: get random gun (not in excludeIds)
function getRandomGun(excludeIds) {
	var pool = [];
	for (var i = 0; i < GUNS.length; ++i) {
		if (!excludeIds || excludeIds.indexOf(GUNS[i].id) === -1) pool.push(GUNS[i]);
	}
	if (pool.length === 0) pool = GUNS;
	return pool[Math.floor(Math.random() * pool.length)];
}
var player = null;
var enemies = [];
var bullets = [];
var gunDrops = [];
var score = 0;
var scoreTxt = null;
var gunTxt = null;
var wave = 1;
var ticksToNextWave = 0;
var playerGuns = [];
var currentGunIndex = 0;
var fireCooldown = 0;
var dragging = false;
var dragOffsetX = 0;
var dragOffsetY = 0;
var lastTouchX = 0;
var lastTouchY = 0;
var gameArea = {
	x: 0,
	y: 0,
	w: 2048,
	h: 2732 - 200
}; // leave some space at bottom for gun UI
// Setup UI
scoreTxt = new Text2('0', {
	size: 120,
	fill: '#fff'
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
gunTxt = new Text2('', {
	size: 70,
	fill: '#fff'
});
gunTxt.anchor.set(0.5, 0);
LK.gui.bottom.addChild(gunTxt);
// Initialize player
player = new Player();
player.x = 2048 / 2;
player.y = 2732 - 350;
game.addChild(player);
// Give player a starting gun
playerGuns = [GUNS[0]];
currentGunIndex = 0;
updateGunUI();
// Spawn first wave
spawnWave(wave);
// Touch controls
game.down = function (x, y, obj) {
	// Only start drag if touch is on player
	var dx = x - player.x;
	var dy = y - player.y;
	if (dx * dx + dy * dy < player.radius * player.radius * 1.5) {
		dragging = true;
		dragOffsetX = player.x - x;
		dragOffsetY = player.y - y;
		lastTouchX = x;
		lastTouchY = y;
	}
};
game.move = function (x, y, obj) {
	if (dragging) {
		// Clamp to game area
		var nx = x + dragOffsetX;
		var ny = y + dragOffsetY;
		if (nx < gameArea.x + player.radius) nx = gameArea.x + player.radius;
		if (nx > gameArea.x + gameArea.w - player.radius) nx = gameArea.x + gameArea.w - player.radius;
		if (ny < gameArea.y + player.radius) ny = gameArea.y + player.radius;
		if (ny > gameArea.y + gameArea.h - player.radius) ny = gameArea.y + gameArea.h - player.radius;
		player.x = nx;
		player.y = ny;
		lastTouchX = x;
		lastTouchY = y;
	}
};
game.up = function (x, y, obj) {
	dragging = false;
};
// Tap bottom of screen to switch gun
game.on('down', function (x, y, obj) {
	if (y > 2732 - 200) {
		// Switch gun
		if (playerGuns.length > 1) {
			currentGunIndex = (currentGunIndex + 1) % playerGuns.length;
			updateGunUI();
			LK.getSound('gunchange').play();
		}
	}
});
// Main update loop
game.update = function () {
	// Player invulnerability
	if (player.invulnTicks > 0) player.invulnTicks--;
	// Firing
	fireCooldown--;
	if (dragging && fireCooldown <= 0) {
		var gun = playerGuns[currentGunIndex];
		fireGun(gun);
		fireCooldown = gun.fireRate;
	}
	// Update bullets
	for (var i = bullets.length - 1; i >= 0; --i) {
		var b = bullets[i];
		b.update();
		// Remove if out of bounds
		if (b.x < -100 || b.x > 2148 || b.y < -100 || b.y > 2832) {
			b.destroy();
			bullets.splice(i, 1);
			continue;
		}
		// Collisions
		if (b.fromPlayer) {
			// Hit enemy
			for (var j = enemies.length - 1; j >= 0; --j) {
				var e = enemies[j];
				var dx = b.x - e.x;
				var dy = b.y - e.y;
				var dist = dx * dx + dy * dy;
				if (dist < (b.radius + e.radius) * (b.radius + e.radius)) {
					e.hp -= b.damage;
					LK.getSound('enemyhit').play();
					b.destroy();
					bullets.splice(i, 1);
					if (e.hp <= 0) {
						// Enemy dies
						spawnGunDrop(e.x, e.y);
						e.destroy();
						enemies.splice(j, 1);
						score += 10;
						scoreTxt.setText(score);
					}
					break;
				}
			}
		} else {
			// Enemy bullet hits player
			var dx = b.x - player.x;
			var dy = b.y - player.y;
			var dist = dx * dx + dy * dy;
			if (dist < (b.radius + player.radius) * (b.radius + player.radius)) {
				if (player.invulnTicks <= 0) {
					LK.effects.flashScreen(0xff0000, 600);
					player.setInvulnerable(40);
					b.destroy();
					bullets.splice(i, 1);
					// Game over
					LK.showGameOver();
					return;
				}
			}
		}
	}
	// Update enemies
	for (var i = enemies.length - 1; i >= 0; --i) {
		var e = enemies[i];
		e.update();
		// Remove if out of bounds
		if (e.x < -120 || e.x > 2168 || e.y > 2832) {
			e.destroy();
			enemies.splice(i, 1);
			continue;
		}
		// Enemy collides with player
		var dx = e.x - player.x;
		var dy = e.y - player.y;
		var dist = dx * dx + dy * dy;
		if (dist < (e.radius + player.radius) * (e.radius + player.radius)) {
			if (player.invulnTicks <= 0) {
				LK.effects.flashScreen(0xff0000, 600);
				player.setInvulnerable(40);
				// Game over
				LK.showGameOver();
				return;
			}
		}
		// Enemy fires at player
		if (Math.random() < 0.008 + wave * 0.001) {
			var dir = Math.atan2(player.y - e.y, player.x - e.x);
			var eb = new Bullet();
			eb.init('bullet_basic', 18 + Math.random() * 6, dir, 1, false);
			eb.x = e.x;
			eb.y = e.y;
			bullets.push(eb);
			game.addChild(eb);
		}
	}
	// Update gun drops
	for (var i = gunDrops.length - 1; i >= 0; --i) {
		var g = gunDrops[i];
		g.update();
		// Remove if out of bounds
		if (g.y > 2832) {
			g.destroy();
			gunDrops.splice(i, 1);
			continue;
		}
		// Pickup
		var dx = g.x - player.x;
		var dy = g.y - player.y;
		var dist = dx * dx + dy * dy;
		if (dist < (g.radius + player.radius) * (g.radius + player.radius)) {
			// Add gun if not already owned
			if (!hasGun(g.gun.id)) {
				playerGuns.push(g.gun);
				currentGunIndex = playerGuns.length - 1;
				updateGunUI();
				LK.getSound('pickup').play();
			}
			g.destroy();
			gunDrops.splice(i, 1);
		}
	}
	// Next wave
	if (enemies.length === 0 && gunDrops.length === 0 && ticksToNextWave <= 0) {
		ticksToNextWave = 60;
	}
	if (ticksToNextWave > 0) {
		ticksToNextWave--;
		if (ticksToNextWave === 0) {
			wave++;
			spawnWave(wave);
		}
	}
};
// Helper: fire gun
function fireGun(gun) {
	for (var i = 0; i < gun.bulletsPerShot; ++i) {
		var b = new Bullet();
		var spread = gun.spread * (Math.random() - 0.5);
		var dir = -Math.PI / 2 + spread + (gun.bulletsPerShot > 1 ? (i - (gun.bulletsPerShot - 1) / 2) * gun.spread : 0);
		b.init(gun.bulletAsset, gun.bulletSpeed, dir, gun.damage, true);
		b.x = player.x;
		b.y = player.y - player.radius;
		bullets.push(b);
		game.addChild(b);
	}
	LK.getSound('shoot').play();
}
// Helper: spawn wave
function spawnWave(w) {
	var n = 3 + Math.floor(w * 1.5);
	for (var i = 0; i < n; ++i) {
		var e = new Enemy();
		e.x = 200 + Math.random() * (2048 - 400);
		e.y = -100 - Math.random() * 200;
		e.hp = 2 + Math.floor(w / 2);
		e.speed = 7 + Math.random() * 3 + w * 0.2;
		enemies.push(e);
		game.addChild(e);
	}
}
// Helper: spawn gun drop
function spawnGunDrop(x, y) {
	// 50% chance to drop a gun, only if player doesn't have all guns
	if (playerGuns.length >= GUNS.length) return;
	if (Math.random() < 0.5) {
		var exclude = [];
		for (var i = 0; i < playerGuns.length; ++i) exclude.push(playerGuns[i].id);
		var gun = getRandomGun(exclude);
		var g = new GunDrop();
		g.x = x;
		g.y = y;
		g.setGun(gun);
		gunDrops.push(g);
		game.addChild(g);
	}
}
// Helper: update gun UI
function updateGunUI() {
	var gun = playerGuns[currentGunIndex];
	gunTxt.setText("Gun: " + gun.name + "  (Tap here to switch)");
	gunTxt.setStyle({
		fill: "#" + gun.color.toString(16)
	});
}
// Helper: has gun
function hasGun(id) {
	for (var i = 0; i < playerGuns.length; ++i) if (playerGuns[i].id === id) return true;
	return false;
}

===================================================================
--- original.js
+++ change.js
@@ -116,12 +116,12 @@
 
 /**** 
 * Game Code
 ****/ 
-// Gun definitions
-// Sounds
-// Guns (shapes for now, will be replaced by images automatically)
 // Game state
+// Guns (shapes for now, will be replaced by images automatically)
+// Sounds
+// Gun definitions
 var GUNS = [{
 	id: 'basic',
 	name: 'Basic Gun',
 	bulletAsset: 'bullet_basic',
@@ -442,9 +442,11 @@
 // Helper: update gun UI
 function updateGunUI() {
 	var gun = playerGuns[currentGunIndex];
 	gunTxt.setText("Gun: " + gun.name + "  (Tap here to switch)");
-	gunTxt.style.fill = "#" + gun.color.toString(16);
+	gunTxt.setStyle({
+		fill: "#" + gun.color.toString(16)
+	});
 }
 // Helper: has gun
 function hasGun(id) {
 	for (var i = 0; i < playerGuns.length; ++i) if (playerGuns[i].id === id) return true;