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

/**** 
* Classes
****/ 
// Bonus class
var Bonus = Container.expand(function () {
	var self = Container.call(this);
	var bonusGfx = self.attachAsset('bonus', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Update: move down (relative to world)
	self.update = function (speed) {
		self.y += speed;
	};
	return self;
});
// Climber (player) class
var Climber = Container.expand(function () {
	var self = Container.call(this);
	var climberGfx = self.attachAsset('climber', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// --- Trail logic ---
	// Store last position for trail
	self.lastTrailX = undefined;
	self.lastTrailY = undefined;
	self.trailCooldown = 0;
	// Helper: spawn a single orange trail segment at (x, y)
	self.spawnTrail = function (x, y) {
		// Use a simple orange ellipse as the trail segment
		var trail = LK.getAsset('trail_orange', {
			anchorX: 0.5,
			anchorY: 0.5,
			x: x,
			y: y,
			scaleX: 0.7,
			scaleY: 0.4,
			alpha: 0.5
		});
		// If asset doesn't exist yet, create it as a shape
		if (!trail) {
			trail = LK.getAsset('trail_orange', {
				anchorX: 0.5,
				anchorY: 0.5,
				x: x,
				y: y,
				scaleX: 0.7,
				scaleY: 0.4,
				alpha: 0.5
			});
		}
		// Add to game
		if (game) game.addChild(trail);
		// Animate fade out and shrink, then destroy
		tween(trail, {
			alpha: 0,
			scaleX: 0.2,
			scaleY: 0.1
		}, {
			duration: 320,
			easing: tween.quadIn,
			onFinish: function onFinish() {
				if (trail && trail.parent) trail.parent.removeChild(trail);
			}
		});
	};
	// State: which wall (0 = left, 1 = right)
	self.wallSide = 0;
	// Vertical speed (pixels per tick)
	self.vy = 10;
	// Horizontal jump speed (pixels per tick)
	self.vx = 0;
	// Is currently jumping
	self.isJumping = false;
	// Target wall x
	self.targetX = 0;
	// Jump to the other wall
	self.jump = function () {
		// If already jumping, allow to interrupt and jump to the other wall
		if (self.isJumping) {
			// Instantly stop current tween by setting isJumping to false
			self.isJumping = false;
		}
		self.wallSide = 1 - self.wallSide;
		self.isJumping = true;
		// Set target x (climber sits just outside the wall, not inside)
		if (self.wallSide === 0) {
			self.targetX = wallLeftX + wallWidth / 2 + climberWidth / 2 + 2 * GAME_SCALE;
		} else {
			self.targetX = wallRightX - wallWidth / 2 - climberWidth / 2 - 2 * GAME_SCALE;
		}
		// Add a diagonal jump: also move y a bit up, then back to fixed y
		var jumpPeakY = self.y - 180 * GAME_SCALE; // jump up by 180px, scaled
		var originalY = self.y;
		// Determine tilt direction: right jump = tilt left, left jump = tilt right
		var tiltAngle = 0;
		if (self.wallSide === 0) {
			// Jumping to left wall, tilt slightly right
			tiltAngle = Math.PI / 16;
		} else {
			// Jumping to right wall, tilt slightly left
			tiltAngle = -Math.PI / 16;
		}
		// Animate jump with smooth physics using easing for both X and Y
		// Also animate rotation for tilt
		tween(self, {
			x: self.targetX,
			y: jumpPeakY,
			rotation: tiltAngle
		}, {
			duration: 180,
			easing: tween.cubicOut,
			onFinish: function onFinish() {
				// Fall back to original y and reset tilt with smooth ease
				tween(self, {
					y: originalY,
					rotation: 0
				}, {
					duration: 180,
					easing: tween.bounceOut,
					onFinish: function onFinish() {
						self.x = self.targetX;
						self.isJumping = false;
					}
				});
			}
		});
	};
	// Update: move up and spawn trail
	self.update = function () {
		// Move up
		self.y -= self.vy;
		// Trail: spawn a segment if moved enough
		if (self.lastTrailX === undefined || self.lastTrailY === undefined) {
			self.lastTrailX = self.x;
			self.lastTrailY = self.y;
		}
		// Only spawn trail if moved at least 18px (vertical) or 8px (horizontal)
		var dx = self.x - self.lastTrailX;
		var dy = self.y - self.lastTrailY;
		if (dx * dx + dy * dy > 64 * GAME_SCALE * GAME_SCALE) {
			self.spawnTrail(self.x, self.y + climberHeight * 0.18);
			self.lastTrailX = self.x;
			self.lastTrailY = self.y;
		}
	};
	return self;
});
// Obstacle class
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var obsGfx = self.attachAsset('obstacle', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Update: move down (relative to world)
	self.update = function (speed) {
		self.y += speed;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x1e2a38
});

/**** 
* Game Code
****/ 
// Add two background images for infinite vertical scroll
var backgroundImage1 = LK.getAsset('background', {
	anchorX: 0,
	anchorY: 0,
	x: 0,
	y: 0,
	scaleX: 2048 / 2048,
	scaleY: 2732 / 2732
});
var backgroundImage2 = LK.getAsset('background', {
	anchorX: 0,
	anchorY: 0,
	x: 0,
	y: -3640.89,
	// Place second image right above the first
	scaleX: 2048 / 2048,
	scaleY: 2732 / 2732
});
game.addChild(backgroundImage1);
game.addChild(backgroundImage2);
// Play background music
LK.playMusic('bgmusic');
// --- Fail screen state ---
// --- Constants ---
// Scale factor for all gameplay elements
var failScreenActive = false;
var failScreenTimeout = null;
var failScreenContainer = null;
var GAME_SCALE = 1.2;
var wallWidth = 180 * GAME_SCALE;
var climberWidth = 120 * GAME_SCALE;
var climberHeight = 120 * GAME_SCALE;
// Make the gap between walls much narrower and ensure climber fits
var wallGap = 420 * 1.4 * GAME_SCALE; // Increased by 40% and scaled by 1.2x
var wallLeftX = (2048 - wallGap) / 2 - wallWidth / 2;
var wallRightX = (2048 + wallGap) / 2 + wallWidth / 2;
var playTopMargin = 100 * GAME_SCALE; // leave top 100px for menu, scaled
var playBottomMargin = 0;
// --- State ---
var climber;
var obstacles = [];
var bonuses = [];
var distance = 0; // in pixels
var bonusScore = 0;
var scrollSpeed = 18 * GAME_SCALE; // initial vertical speed (pixels per tick) - scaled
var speedIncreaseEvery = 400 * GAME_SCALE; // increase speed more frequently, scaled
var speedIncreaseAmount = 1.2; // increase speed more per step (no scaling needed)
var maxScrollSpeed = 48 * GAME_SCALE; // allow higher max speed, scaled
var lastObstacleY = 0;
var lastBonusY = 0;
var obstacleSpacing = 420 * 1.1 * GAME_SCALE; // min vertical distance between obstacles, increased by 10% and scaled
var bonusSpacing = 900 * GAME_SCALE; // min vertical distance between bonuses, scaled
var scoreTxt;
// --- Obstacle damage protection & opacity ---
var obstacleDamageEnabled = false;
var obstacleOpacity = 0.35; // Start with 35% opacity
// Set all current obstacles to given opacity
function setAllObstacleOpacity(alpha) {
	for (var i = 0; i < obstacles.length; i++) {
		if (obstacles[i] && obstacles[i].children && obstacles[i].children[0]) {
			obstacles[i].children[0].alpha = alpha;
		}
	}
}
// Set initial opacity
setAllObstacleOpacity(obstacleOpacity);
// At 1s: blink between 0.35 and 0.6 for 1s, then set to 0.6
LK.setTimeout(function () {
	var blinkCount = 0;
	var blinkInterval = LK.setInterval(function () {
		blinkCount++;
		// Alternate between 0.35 and 0.6 every 100ms
		obstacleOpacity = blinkCount % 2 === 0 ? 0.35 : 0.6;
		setAllObstacleOpacity(obstacleOpacity);
		if (blinkCount >= 10) {
			// 1s total (10 blinks)
			LK.clearInterval(blinkInterval);
			obstacleOpacity = 0.6;
			setAllObstacleOpacity(obstacleOpacity);
		}
	}, 100);
}, 1000);
// At 2s: set to 1.0 and enable damage
LK.setTimeout(function () {
	obstacleDamageEnabled = true;
	obstacleOpacity = 1.0;
	setAllObstacleOpacity(obstacleOpacity);
	// After 2s, always force obstacleOpacity to 1.0 for all future obstacles
	setAllObstacleOpacity = function setAllObstacleOpacity(alpha) {
		for (var i = 0; i < obstacles.length; i++) {
			if (obstacles[i] && obstacles[i].children && obstacles[i].children[0]) {
				obstacles[i].children[0].alpha = 1.0;
			}
		}
	};
}, 2000);
// --- Walls ---
// Walls removed: no wall graphics are added to the game
// --- Climber ---
climber = new Climber();
climber.x = wallLeftX + wallWidth / 2 + climberWidth / 2;
climber.y = 2732 / 2; // start at vertical center of the screen (not scaled)
game.addChild(climber);
// --- Score Display ---
scoreTxt = new Text2('0 m', {
	size: 120 * GAME_SCALE * 0.7,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0, 0); // anchor left
scoreTxt.y = 310 * GAME_SCALE - 200; // move 100 units lower than before, scaled
LK.gui.topLeft.addChild(scoreTxt);
// --- Bonus Count Display (yellow ball icon + count) ---
var bonusIcon = LK.getAsset('bonus', {
	anchorX: 0,
	anchorY: 0,
	// Reduce icon size by 20% (relative to previous)
	scaleX: 0.5 * GAME_SCALE * 0.7 * 3 * 0.8,
	scaleY: 0.5 * GAME_SCALE * 0.7 * 3 * 0.8,
	x: 0,
	y: scoreTxt.y + scoreTxt.height + 10 * GAME_SCALE
});
LK.gui.topLeft.addChild(bonusIcon);
var bonusCountTxt = new Text2('0', {
	size: 90 * GAME_SCALE * 0.7 * 1.4,
	// Increase by 40%
	fill: 0xFFF700
});
bonusCountTxt.anchor.set(0, 0);
bonusCountTxt.x = bonusIcon.x + bonusIcon.width + 16 * GAME_SCALE;
// Move count 20 units lower
bonusCountTxt.y = bonusIcon.y + (bonusIcon.height - bonusCountTxt.height) / 2;
LK.gui.topLeft.addChild(bonusCountTxt);
// Helper to update bonus count text
function updateBonusCountText() {
	bonusCountTxt.setText(bonusScore + "");
}
updateBonusCountText();
// Heart (life) display using custom asset
var maxLives = 3;
var lives = maxLives;
var heartIcons = [];
for (var i = 0; i < maxLives; i++) {
	// Use your custom heart asset here. Make sure to add it in the Assets section, e.g.:
	// LK.init.image('heart', {width:100, height:100, id:'your_heart_asset_id'})
	var heart = LK.getAsset('heart', {
		anchorX: 1,
		anchorY: 0,
		scaleX: 0.7 * GAME_SCALE,
		scaleY: 0.7 * GAME_SCALE,
		x: -50,
		y: 100 + i * 120 * GAME_SCALE * 0.7
	});
	LK.gui.topRight.addChild(heart);
	heartIcons.push(heart);
}
function updateHearts() {
	for (var i = 0; i < heartIcons.length; i++) {
		heartIcons[i].alpha = i < lives ? 1 : 0.25;
	}
}
updateHearts();
// --- Helper: format distance ---
function formatDistance(px) {
	var meters = Math.floor(px / 10);
	if (meters < 1000) return meters + " m";
	return (meters / 1000).toFixed(2) + " km";
}
// --- Helper: update score text ---
function updateScoreText() {
	var meters = Math.floor(distance / 10);
	scoreTxt.setText(meters + " m");
}
// --- Helper: spawn obstacle ---
function spawnObstacle() {
	// Randomly pick left or right wall
	var side = Math.random() < 0.5 ? 0 : 1;
	var obs = new Obstacle();
	if (side === 0) {
		obs.x = wallLeftX + wallWidth / 2 + climberWidth / 2 + 2 * GAME_SCALE;
		obs.children[0].flipX = 1; // Mirror horizontally for left-side obstacles
	} else {
		obs.x = wallRightX - wallWidth / 2 - climberWidth / 2 - 2 * GAME_SCALE;
		obs.children[0].flipX = 0; // No flip for right-side obstacles
	}
	// Set opacity according to current global value
	if (obs.children && obs.children[0]) {
		// After 800m, always set to 1.0
		if (distance >= 8000) {
			obs.children[0].alpha = 1.0;
		} else {
			obs.children[0].alpha = obstacleOpacity;
		}
	}
	obs.y = lastObstacleY - obstacleSpacing - Math.random() * 220 * GAME_SCALE;
	obstacles.push(obs);
	game.addChild(obs);
	lastObstacleY = obs.y;
}
// --- Helper: spawn bonus ---
function spawnBonus() {
	var bonus = new Bonus();
	bonus.x = 2048 / 2;
	bonus.y = lastBonusY - bonusSpacing - Math.random() * 400 * GAME_SCALE;
	bonuses.push(bonus);
	game.addChild(bonus);
	lastBonusY = bonus.y;
}
// --- Initial obstacles/bonuses ---
// Start obstacles and bonuses from the bottom of the screen
lastObstacleY = 2732 - climberHeight / 2;
lastBonusY = 2732 - climberHeight / 2;
// (2732 is not scaled, as it's the screen size)
// Delay obstacle and bonus spawning by 1 second, then spawn at 2 second intervals
LK.setTimeout(function () {
	for (var i = 0; i < 6; i++) {
		spawnObstacle();
	}
	for (var i = 0; i < 2; i++) {
		spawnBonus();
	}
	// Set interval to spawn obstacles every 2 seconds (2000ms)
	LK.setInterval(function () {
		spawnObstacle();
	}, 2000);
}, 1000);
// --- Input: tap to jump ---
game.down = function (x, y, obj) {
	// Allow jump if not already moving to the same wall (ignore isJumping)
	var nextWall = 1 - climber.wallSide;
	// Only allow jump if not already moving to that wall
	if (!(climber.isJumping && climber.targetX === (nextWall === 0 ? wallLeftX + wallWidth / 2 + climberWidth / 2 + 2 : wallRightX - wallWidth / 2 - climberWidth / 2 - 2))) {
		climber.jump();
	}
};
// --- Move handler (not used for drag, but required by LK) ---
game.move = function (x, y, obj) {};
// --- Main update loop ---
game.update = function () {
	if (failScreenActive) {
		// Block gameplay update while fail screen is shown
		return;
	}
	// --- Infinite vertical background scroll ---
	// Move both backgrounds down at 1/20th of scrollSpeed
	var bgScrollSpeed = scrollSpeed / 20;
	backgroundImage1.y += bgScrollSpeed;
	backgroundImage2.y += bgScrollSpeed;
	// If a background image moves off the bottom, move it above the other
	if (backgroundImage1.y >= 3640.89) {
		backgroundImage1.y = backgroundImage2.y - 3640.89;
	}
	if (backgroundImage2.y >= 3640.89) {
		backgroundImage2.y = backgroundImage1.y - 3640.89;
	}
	// Increase/decrease/stop speed at milestones
	if (!game.lastSpeedMilestone) game.lastSpeedMilestone = 0;
	var metersNow = Math.floor(distance / 10);
	// --- NEW: At 500m, increase speed by 0.3 only once ---
	if (!game.did500mSpeedup && metersNow >= 500) {
		scrollSpeed += 0.3;
		climber.vy = scrollSpeed;
		game.did500mSpeedup = true;
	}
	// 0-4k: increase speed every 1000m, then stop increasing after 4000m
	if (metersNow - game.lastSpeedMilestone >= 1000 && metersNow <= 4000) {
		scrollSpeed *= 1.2;
		if (scrollSpeed > maxScrollSpeed) scrollSpeed = maxScrollSpeed;
		climber.vy = scrollSpeed;
		// Increase obstacleSpacing by 0.1x (10%) every 1000m
		obstacleSpacing *= 1.1;
		game.lastSpeedMilestone += 1000;
	}
	// 10k-15k: decrease speed by 0.08 per 1000m
	else if (metersNow - game.lastSpeedMilestone >= 1000 && metersNow > 10000 && metersNow <= 15000) {
		scrollSpeed -= 0.08;
		if (scrollSpeed < 1) scrollSpeed = 1; // Prevent negative/zero speed
		climber.vy = scrollSpeed;
		game.lastSpeedMilestone += 1000;
	}
	// 15k-20k: increase speed by 0.08 per 1000m
	else if (metersNow - game.lastSpeedMilestone >= 1000 && metersNow > 15000 && metersNow <= 20000) {
		scrollSpeed += 0.08;
		if (scrollSpeed > maxScrollSpeed) scrollSpeed = maxScrollSpeed;
		climber.vy = scrollSpeed;
		game.lastSpeedMilestone += 1000;
	}
	// After 15k: every 500m, increase speed by 0.1
	if (!game.last500mSpeedMilestone) game.last500mSpeedMilestone = 15000;
	if (metersNow >= 15000 && metersNow - game.last500mSpeedMilestone >= 500) {
		scrollSpeed += 0.1;
		if (scrollSpeed > maxScrollSpeed) scrollSpeed = maxScrollSpeed;
		climber.vy = scrollSpeed;
		game.last500mSpeedMilestone += 500;
	}
	// After 20k: stop increasing speed, no further changes
	// Keep climber fixed at the vertical center of the screen, move obstacles/bonuses down by scrollSpeed
	var screenClimberY = 2732 / 2; // fixed Y position for climber at vertical center (not scaled)
	climber.y = screenClimberY;
	// Move all obstacles and bonuses down by scrollSpeed
	for (var i = 0; i < obstacles.length; i++) {
		obstacles[i].y += scrollSpeed;
		// After 800m (8000px), always force obstacle opacity to 1.0
		if (distance >= 8000 && obstacles[i].children && obstacles[i].children[0]) {
			obstacles[i].children[0].alpha = 1.0;
		}
	}
	for (var j = 0; j < bonuses.length; j++) {
		bonuses[j].y += scrollSpeed;
	}
	// Walls removed: no wall movement needed
	// Update distance
	distance += scrollSpeed;
	updateScoreText();
	// Move obstacles and check collision
	for (var i = obstacles.length - 1; i >= 0; i--) {
		var obs = obstacles[i];
		// If obstacle goes off the bottom, move it back to the top with new random Y and side
		if (obs.y > 2732 + 100 * GAME_SCALE) {
			// Randomly pick left or right wall
			var side = Math.random() < 0.5 ? 0 : 1;
			if (side === 0) {
				obs.x = wallLeftX + wallWidth / 2 + climberWidth / 2 + 2 * GAME_SCALE;
				obs.children[0].flipX = 1; // Mirror horizontally for left-side obstacles
			} else {
				obs.x = wallRightX - wallWidth / 2 - climberWidth / 2 - 2 * GAME_SCALE;
				obs.children[0].flipX = 0; // No flip for right-side obstacles
			}
			// Set opacity according to current global value
			if (obs.children && obs.children[0]) {
				// After 800m, always set to 1.0
				if (distance >= 8000) {
					obs.children[0].alpha = 1.0;
				} else {
					obs.children[0].alpha = obstacleOpacity;
				}
			}
			// Place above the highest obstacle
			var highestY = climber.y - 400 * GAME_SCALE;
			for (var k = 0; k < obstacles.length; k++) {
				if (obstacles[k].y < highestY) highestY = obstacles[k].y;
			}
			obs.y = highestY - obstacleSpacing - Math.random() * 220 * GAME_SCALE;
			lastObstacleY = obs.y;
		}
		// Collision: only if climber is on same wall and overlaps in Y
		if (Math.abs(obs.x - climber.x) < climberWidth / 2 + 10 * GAME_SCALE && Math.abs(obs.y - screenClimberY) < climberHeight / 2 + 30 * GAME_SCALE) {
			if (obstacleDamageEnabled) {
				LK.effects.flashScreen(0xff0000, 800);
				// Play obstacle hit sound
				LK.getSound('obstacle_hit').play();
				lives--;
				updateHearts();
				if (lives <= 0) {
					// Play fail sound
					LK.getSound('fail').play();
					// Show fail screen for 2 seconds with score
					failScreenActive = true;
					failScreenContainer = new Container();
					// Semi-transparent black background
					var bg = LK.getAsset('centerCircle', {
						anchorX: 0.5,
						anchorY: 0.5,
						scaleX: 20,
						scaleY: 20,
						x: 2048 / 2,
						y: 2732 / 2,
						alpha: 0.7,
						tint: 0x000000
					});
					failScreenContainer.addChild(bg);
					// "Failed!" text
					var failTxt = new Text2("Failed!", {
						size: 180 * GAME_SCALE,
						fill: 0xFF4444
					});
					failTxt.anchor.set(0.5, 0.5);
					failTxt.x = 2048 / 2;
					failTxt.y = 2732 / 2 - 180 * GAME_SCALE;
					failScreenContainer.addChild(failTxt);
					// Only distance value (no 'Skor:' label)
					var scoreFailTxt = new Text2(Math.floor(distance / 10) + " m", {
						size: 120 * GAME_SCALE,
						fill: "#fff"
					});
					scoreFailTxt.anchor.set(0.5, 0.5);
					scoreFailTxt.x = 2048 / 2;
					scoreFailTxt.y = 2732 / 2 + 20 * GAME_SCALE;
					failScreenContainer.addChild(scoreFailTxt);
					// Bonus icon and count (centered, icon above, count below)
					var bonusFailIcon = LK.getAsset('bonus', {
						anchorX: 0.5,
						anchorY: 0.5,
						// %5 büyüt
						scaleX: 0.7 * GAME_SCALE * 1.05,
						scaleY: 0.7 * GAME_SCALE * 1.05,
						x: 2048 / 2,
						// 10 birim aşağıya indir
						y: 2732 / 2 + 120 * GAME_SCALE + 10
					});
					failScreenContainer.addChild(bonusFailIcon);
					var bonusFailCount = new Text2(bonusScore + "", {
						size: 100 * GAME_SCALE,
						fill: 0xFFF700
					});
					bonusFailCount.anchor.set(0.5, 0);
					bonusFailCount.x = 2048 / 2;
					bonusFailCount.y = bonusFailIcon.y + bonusFailIcon.height / 2 + 10 * GAME_SCALE;
					failScreenContainer.addChild(bonusFailCount);
					game.addChild(failScreenContainer);
					// After 2 seconds, remove fail screen and show game over
					failScreenTimeout = LK.setTimeout(function () {
						if (failScreenContainer && failScreenContainer.parent) {
							failScreenContainer.parent.removeChild(failScreenContainer);
						}
						failScreenActive = false;
						LK.showGameOver();
					}, 2000);
					return;
				}
				// Temporary invulnerability for 1s after hit
				obstacleDamageEnabled = false;
				setAllObstacleOpacity(0.5);
				LK.setTimeout(function () {
					obstacleDamageEnabled = true;
					setAllObstacleOpacity(1.0);
				}, 1000);
			}
		}
	}
	// Move bonuses and check collection
	for (var j = bonuses.length - 1; j >= 0; j--) {
		var b = bonuses[j];
		// If bonus goes off the bottom, move it back to the top (like obstacles)
		if (b.y > 2732 + 100 * GAME_SCALE) {
			// Place above the highest bonus
			var highestBonusY = climber.y - 800 * GAME_SCALE;
			for (var k = 0; k < bonuses.length; k++) {
				if (bonuses[k].y < highestBonusY) highestBonusY = bonuses[k].y;
			}
			b.y = highestBonusY - bonusSpacing - Math.random() * 400 * GAME_SCALE;
			lastBonusY = b.y;
			continue;
		}
		// Collect
		if (Math.abs(b.x - climber.x) < climberWidth / 2 + 40 * GAME_SCALE && Math.abs(b.y - screenClimberY) < climberHeight / 2 + 40 * GAME_SCALE) {
			bonusScore += 1;
			// Add 50 units to distance when collecting a yellow bonus
			distance += 50;
			updateScoreText();
			updateBonusCountText();
			LK.effects.flashObject(b, 0xffff00, 400);
			// Play bonus collect sound
			LK.getSound('bonus_collect').play();
			// Move collected bonus to top (infinite)
			var highestBonusY = climber.y - 800 * GAME_SCALE;
			for (var k = 0; k < bonuses.length; k++) {
				if (bonuses[k].y < highestBonusY) highestBonusY = bonuses[k].y;
			}
			b.y = highestBonusY - bonusSpacing - Math.random() * 400 * GAME_SCALE;
			lastBonusY = b.y;
			continue;
		}
	}
	// Spawn new obstacles/bonuses as needed for infinite runner
	while (lastObstacleY > climber.y - 1200 * GAME_SCALE) {
		spawnObstacle();
	}
	while (lastBonusY > climber.y - 1800 * GAME_SCALE) {
		spawnBonus();
	}
};
// --- Reset state on game over ---
game.on('gameover', function () {
	// All state will be reset by LK, so nothing to do here
	bonusScore = 0;
	updateBonusCountText && updateBonusCountText();
	// Remove fail screen if still present
	if (failScreenTimeout) {
		LK.clearTimeout(failScreenTimeout);
		failScreenTimeout = null;
	}
	if (failScreenContainer && failScreenContainer.parent) {
		failScreenContainer.parent.removeChild(failScreenContainer);
		failScreenContainer = null;
	}
	failScreenActive = false;
});
// --- You win (not used in endless) ---
game.on('youwin', function () {
	// Not used
	bonusScore = 0;
	updateBonusCountText && updateBonusCountText();
});

===================================================================
--- original.js
+++ change.js
@@ -175,20 +175,28 @@
 
 /**** 
 * Game Code
 ****/ 
-// Add your custom heart image asset here (replace id with your own asset id)
-// Customizable background image asset (replace id with your own image if desired)
-// Add background image to the game scene
-var backgroundImage = LK.getAsset('background', {
+// Add two background images for infinite vertical scroll
+var backgroundImage1 = LK.getAsset('background', {
 	anchorX: 0,
 	anchorY: 0,
 	x: 0,
 	y: 0,
 	scaleX: 2048 / 2048,
 	scaleY: 2732 / 2732
 });
-game.addChild(backgroundImage);
+var backgroundImage2 = LK.getAsset('background', {
+	anchorX: 0,
+	anchorY: 0,
+	x: 0,
+	y: -3640.89,
+	// Place second image right above the first
+	scaleX: 2048 / 2048,
+	scaleY: 2732 / 2732
+});
+game.addChild(backgroundImage1);
+game.addChild(backgroundImage2);
 // Play background music
 LK.playMusic('bgmusic');
 // --- Fail screen state ---
 // --- Constants ---
@@ -409,8 +417,20 @@
 	if (failScreenActive) {
 		// Block gameplay update while fail screen is shown
 		return;
 	}
+	// --- Infinite vertical background scroll ---
+	// Move both backgrounds down at 1/20th of scrollSpeed
+	var bgScrollSpeed = scrollSpeed / 20;
+	backgroundImage1.y += bgScrollSpeed;
+	backgroundImage2.y += bgScrollSpeed;
+	// If a background image moves off the bottom, move it above the other
+	if (backgroundImage1.y >= 3640.89) {
+		backgroundImage1.y = backgroundImage2.y - 3640.89;
+	}
+	if (backgroundImage2.y >= 3640.89) {
+		backgroundImage2.y = backgroundImage1.y - 3640.89;
+	}
 	// Increase/decrease/stop speed at milestones
 	if (!game.lastSpeedMilestone) game.lastSpeedMilestone = 0;
 	var metersNow = Math.floor(distance / 10);
 	// --- NEW: At 500m, increase speed by 0.3 only once ---