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

/**** 
* Classes
****/ 
// Coin class
var Coin = Container.expand(function () {
	var self = Container.call(this);
	self.lane = 1;
	self.collected = false;
	// Attach asset
	var coinAsset = self.attachAsset('coin', {
		anchorX: 0.5,
		anchorY: 1
	});
	// Update per frame
	self.update = function () {
		self.y += game.speed * game.deltaTime;
	};
	return self;
});
// Obstacle class (train/barrier)
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	// lane: 0,1,2
	self.lane = 1;
	self.type = 'barrier'; // 'train' or 'barrier'
	self.passed = false;
	// Attach asset
	self.setType = function (type) {
		self.type = type;
		if (self.asset) {
			self.removeChild(self.asset);
		}
		if (type === 'train') {
			self.asset = self.attachAsset('train', {
				anchorX: 0.5,
				anchorY: 1
			});
		} else {
			self.asset = self.attachAsset('barrier', {
				anchorX: 0.5,
				anchorY: 1
			});
		}
	};
	// Update per frame
	self.update = function () {
		self.y += game.speed * game.deltaTime;
	};
	return self;
});
// Player character class
var Runner = Container.expand(function () {
	var self = Container.call(this);
	// Attach runner asset (box, blue)
	var runnerAsset = self.attachAsset('runner', {
		anchorX: 0.5,
		anchorY: 1
	});
	// Lane index: 0 (left), 1 (center), 2 (right)
	self.lane = 1;
	self.targetLane = 1;
	self.laneX = [game.laneLeftX, game.laneCenterX, game.laneRightX];
	// Jumping and ducking state
	self.isJumping = false;
	self.isDucking = false;
	self.jumpStartY = 0;
	self.jumpTime = 0;
	self.duckTime = 0;
	// Move to lane (with tween)
	self.moveToLane = function (lane) {
		if (lane < 0) lane = 0;
		if (lane > 2) lane = 2;
		if (lane !== self.lane) {
			self.targetLane = lane;
			tween(self, {
				x: self.laneX[lane]
			}, {
				duration: 120,
				easing: tween.cubicOut
			});
			self.lane = lane;
		}
	};
	// Start jump
	self.jump = function () {
		if (!self.isJumping && !self.isDucking) {
			self.isJumping = true;
			self.jumpStartY = self.y;
			self.jumpTime = 0;
		}
	};
	// Start duck
	self.duck = function () {
		if (!self.isJumping && !self.isDucking) {
			self.isDucking = true;
			self.duckTime = 0;
			// Shrink runner visually
			tween(runnerAsset, {
				scaleY: 0.5
			}, {
				duration: 80,
				easing: tween.cubicIn
			});
		}
	};
	// Update per frame
	self.update = function () {
		// Jumping: simple parabolic jump
		if (self.isJumping) {
			self.jumpTime += game.deltaTime;
			var t = self.jumpTime / game.jumpDuration;
			if (t > 1) t = 1;
			// Parabola: y = -4h * (t-0.5)^2 + h
			var h = game.jumpHeight;
			var dy = -4 * h * (t - 0.5) * (t - 0.5) + h;
			self.y = self.jumpStartY - dy;
			if (t >= 1) {
				self.isJumping = false;
				self.y = self.jumpStartY;
			}
		}
		// Ducking: stay ducked for duckDuration
		if (self.isDucking) {
			self.duckTime += game.deltaTime;
			if (self.duckTime >= game.duckDuration) {
				self.isDucking = false;
				// Restore runner scale
				tween(runnerAsset, {
					scaleY: 1
				}, {
					duration: 80,
					easing: tween.cubicOut
				});
			}
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	// No title, no description
	backgroundColor: 0x000000
});

/**** 
* Game Code
****/ 
// --- Game constants ---
game.laneCount = 3;
game.laneWidth = 400;
game.laneLeftX = 524;
game.laneCenterX = 1024;
game.laneRightX = 1524;
game.groundY = 2300;
game.runnerY = game.groundY;
game.jumpHeight = 350;
game.jumpDuration = 420; // ms
game.duckDuration = 350; // ms
game.deltaTime = 16.67; // ms, will be updated per frame
game.speed = 50 / 60; // px per frame (50 px/sec at 60 FPS)
game.speedIncrease = 5 / 60 / (60 * 1000 / 16.67); // px per frame per ms (5 px/minute)
game.maxSpeed = 300 / 60; // cap at 300 px/sec (arbitrary, can be adjusted)
game.spawnTimer = 0;
game.spawnInterval = 900; // ms
game.coinSpawnTimer = 0;
game.coinSpawnInterval = 600; // ms
game.distance = 0;
game.coins = 0;
game.lastTick = Date.now();
// --- Asset initialization (shapes) ---
// --- Game objects ---
var runner = new Runner();
runner.x = game.laneCenterX;
runner.y = game.runnerY;
game.addChild(runner);
var obstacles = [];
var coins = [];
// --- GUI ---
var scoreTxt = new Text2('0', {
	size: 110,
	fill: 0xFFF700
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
var coinTxt = new Text2('0', {
	size: 80,
	fill: 0xFFD700
});
coinTxt.anchor.set(0, 0);
coinTxt.x = 120;
coinTxt.y = 0;
LK.gui.top.addChild(coinTxt);
// --- Touch controls (swipe) ---
var touchStartX = 0;
var touchStartY = 0;
var touchStartTime = 0;
var swipeThreshold = 80;
var swipeTime = 350;
// Only allow one swipe per gesture
var swipeUsed = false;
game.down = function (x, y, obj) {
	touchStartX = x;
	touchStartY = y;
	touchStartTime = Date.now();
	swipeUsed = false;
};
game.move = function (x, y, obj) {
	if (swipeUsed) return;
	var dx = x - touchStartX;
	var dy = y - touchStartY;
	var dt = Date.now() - touchStartTime;
	if (dt > swipeTime) return; // Too slow
	// Horizontal swipe
	if (Math.abs(dx) > swipeThreshold && Math.abs(dx) > Math.abs(dy)) {
		if (dx > 0) {
			// Swipe right
			runner.moveToLane(runner.lane + 1);
		} else {
			// Swipe left
			runner.moveToLane(runner.lane - 1);
		}
		swipeUsed = true;
	}
	// Vertical swipe
	else if (Math.abs(dy) > swipeThreshold && Math.abs(dy) > Math.abs(dx)) {
		if (dy < 0) {
			// Swipe up
			runner.jump();
		} else {
			// Swipe down
			runner.duck();
		}
		swipeUsed = true;
	}
};
game.up = function (x, y, obj) {
	// No-op
};
// --- Main update loop ---
game.update = function () {
	// Delta time
	var now = Date.now();
	game.deltaTime = now - game.lastTick;
	if (game.deltaTime > 60) game.deltaTime = 60;
	game.lastTick = now;
	// Increase speed
	if (game.speed < game.maxSpeed) {
		game.speed += game.speedIncrease * game.deltaTime;
		if (game.speed > game.maxSpeed) game.speed = game.maxSpeed;
	}
	// Update runner
	runner.update();
	// Update obstacles
	for (var i = obstacles.length - 1; i >= 0; i--) {
		var obs = obstacles[i];
		obs.update();
		// Remove if off screen
		if (obs.y > 2800) {
			obs.destroy();
			obstacles.splice(i, 1);
			continue;
		}
		// Collision with runner
		if (!obs.passed && obs.lane === runner.lane) {
			// Only check if close enough
			var obsTop = obs.y - obs.asset.height;
			var runnerBottom = runner.y;
			var runnerTop = runner.y - runner.height;
			// For train: must jump over
			if (obs.type === 'train') {
				if (!runner.isJumping && runnerBottom > obsTop && runnerTop < obs.y) {
					// Collision!
					LK.effects.flashScreen(0xff0000, 800);
					LK.showGameOver();
					return;
				}
			}
			// For barrier: must duck under
			else if (obs.type === 'barrier') {
				// Barrier is low, so if not ducking and feet overlap, collision
				if (!runner.isDucking && runnerBottom > obsTop && runnerTop < obs.y) {
					LK.effects.flashScreen(0xff0000, 800);
					LK.showGameOver();
					return;
				}
			}
		}
	}
	// Update coins
	for (var j = coins.length - 1; j >= 0; j--) {
		var coin = coins[j];
		coin.update();
		// Remove if off screen
		if (coin.y > 2800) {
			coin.destroy();
			coins.splice(j, 1);
			continue;
		}
		// Collect coin
		if (!coin.collected && coin.lane === runner.lane) {
			var coinTop = coin.y - coin.height;
			var runnerBottom = runner.y;
			var runnerTop = runner.y - runner.height;
			if (runnerBottom > coinTop && runnerTop < coin.y) {
				coin.collected = true;
				coin.destroy();
				coins.splice(j, 1);
				game.coins += 1;
				coinTxt.setText(game.coins);
			}
		}
	}
	// Spawn obstacles
	game.spawnTimer += game.deltaTime;
	if (game.spawnTimer > game.spawnInterval) {
		game.spawnTimer = 0;
		// Randomly pick lane and type
		var lane = Math.floor(Math.random() * 3);
		var type = Math.random() < 0.6 ? 'train' : 'barrier';
		var obs = new Obstacle();
		obs.lane = lane;
		obs.setType(type);
		obs.x = [game.laneLeftX, game.laneCenterX, game.laneRightX][lane];
		// Spawn obstacles further up (more visible distance)
		obs.y = game.groundY - 1800;
		game.addChild(obs);
		obstacles.push(obs);
	}
	// Spawn coins further up (more visible distance)
	game.coinSpawnTimer += game.deltaTime;
	if (game.coinSpawnTimer > game.coinSpawnInterval) {
		game.coinSpawnTimer = 0;
		var lane = Math.floor(Math.random() * 3);
		var coin = new Coin();
		coin.lane = lane;
		coin.x = [game.laneLeftX, game.laneCenterX, game.laneRightX][lane];
		coin.y = game.groundY - 1500;
		game.addChild(coin);
		coins.push(coin);
	}
	// Update distance and score
	game.distance += game.speed * game.deltaTime * 0.04;
	var score = Math.floor(game.distance) + game.coins * 10;
	scoreTxt.setText(score);
	LK.setScore(score);
};
// --- Place runner at correct y ---
runner.y = game.runnerY;
// --- Place GUI elements ---
scoreTxt.x = 1024;
scoreTxt.y = 30;
coinTxt.y = 30;

===================================================================
--- original.js
+++ change.js
@@ -164,9 +164,9 @@
 game.jumpHeight = 350;
 game.jumpDuration = 420; // ms
 game.duckDuration = 350; // ms
 game.deltaTime = 16.67; // ms, will be updated per frame
-game.speed = 100 / 60; // px per frame (100 px/sec at 60 FPS)
+game.speed = 50 / 60; // px per frame (50 px/sec at 60 FPS)
 game.speedIncrease = 5 / 60 / (60 * 1000 / 16.67); // px per frame per ms (5 px/minute)
 game.maxSpeed = 300 / 60; // cap at 300 px/sec (arbitrary, can be adjusted)
 game.spawnTimer = 0;
 game.spawnInterval = 900; // ms