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

/**** 
* Classes
****/ 
var Bird = Container.expand(function () {
	var self = Container.call(this);
	var birdGraphics = self.attachAsset('bird', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.velocity = 0;
	self.gravity = 0.3;
	self.flapPower = -18;
	self.rotation = 0;
	self.isMonster = false;
	self.monsterEndTime = 0;
	self.isYeti = false;
	self.yetiEndTime = 0;
	self.isOnGround = false;
	self.walkSpeed = 3;
	// Transform into monster
	self.transformToMonster = function () {
		if (!self.isMonster) {
			self.isMonster = true;
			self.monsterEndTime = LK.ticks + 600; // 10 seconds at 60fps
			// Remove current bird graphics
			self.removeChild(birdGraphics);
			// Add monster graphics
			self.monsterGraphics = self.attachAsset('monster', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			// Enhanced abilities
			self.flapPower = -5; // Reduced jump power
			self.gravity = 0.1; // Less gravity
			// Visual effect
			tween(self.monsterGraphics, {
				scaleX: 1.3,
				scaleY: 1.3
			}, {
				duration: 500,
				easing: tween.elasticOut
			});
		}
	};
	// Transform into yeti for winter season
	self.transformToYeti = function () {
		if (!self.isYeti) {
			self.isYeti = true;
			self.yetiEndTime = LK.ticks + 900; // 15 seconds at 60fps
			// Remove current graphics
			if (self.isMonster && self.monsterGraphics) {
				self.removeChild(self.monsterGraphics);
			} else {
				self.removeChild(birdGraphics);
			}
			// Add yeti graphics
			self.yetiGraphics = self.attachAsset('yeti', {
				anchorX: 0.5,
				anchorY: 0.5
			});
			// Set yeti on ground
			self.y = 2732 - 150;
			self.isOnGround = true;
			self.velocity = 0;
			// Yeti abilities
			self.flapPower = -5; // Small jump
			self.gravity = 0.8; // Higher gravity to stay grounded
			// Visual effect
			tween(self.yetiGraphics, {
				scaleX: 1.2,
				scaleY: 1.2
			}, {
				duration: 500,
				easing: tween.elasticOut
			});
		}
	};
	// Transform back to normal bird
	self.transformToNormal = function () {
		if (self.isMonster) {
			self.isMonster = false;
			// Remove monster graphics
			if (self.monsterGraphics) {
				self.removeChild(self.monsterGraphics);
			}
		}
		if (self.isYeti) {
			self.isYeti = false;
			self.isOnGround = false;
			// Remove yeti graphics
			if (self.yetiGraphics) {
				self.removeChild(self.yetiGraphics);
			}
		}
		// Add back bird graphics
		birdGraphics = self.attachAsset('bird', {
			anchorX: 0.5,
			anchorY: 0.5
		});
		// Reset normal abilities
		self.flapPower = -18;
		self.gravity = 0.3;
		// Restart wing animation
		self.startWingAnimation();
	};
	// Start continuous wing flapping animation
	self.startWingAnimation = function () {
		// Create a continuous flapping animation by scaling the bird
		function flapUp() {
			tween(birdGraphics, {
				scaleY: 1.2
			}, {
				duration: 150,
				easing: tween.easeOut,
				onFinish: flapDown
			});
		}
		function flapDown() {
			tween(birdGraphics, {
				scaleY: 0.8
			}, {
				duration: 150,
				easing: tween.easeOut,
				onFinish: flapUp
			});
		}
		// Start the animation cycle
		flapUp();
	};
	// Start wing animation immediately
	self.startWingAnimation();
	self.flap = function () {
		self.velocity = self.flapPower;
		LK.getSound('flap').play();
	};
	self.update = function () {
		// Check if monster time is up
		if (self.isMonster && LK.ticks >= self.monsterEndTime) {
			self.transformToNormal();
		}
		// Check if yeti time is up
		if (self.isYeti && LK.ticks >= self.yetiEndTime) {
			self.transformToNormal();
		}
		// Yeti walking behavior
		if (self.isYeti && self.isOnGround) {
			// Walk left and right on ground
			self.x += Math.sin(LK.ticks * 0.05) * self.walkSpeed;
			// Keep within screen bounds
			if (self.x < 100) self.x = 100;
			if (self.x > 1948) self.x = 1948;
		}
		// Apply physics based on current form
		if (!self.isYeti || !self.isOnGround) {
			self.velocity += self.gravity;
			self.y += self.velocity;
		}
		// Handle collisions based on current form
		if (!self.isMonster && !self.isYeti) {
			// Normal bird - dies on collision
			if (self.y > 2732 - 150) {
				self.y = 2732 - 150;
				gameOver = true;
			}
			// Check ceiling collision
			if (self.y < 50) {
				self.y = 50;
				gameOver = true;
			}
		} else if (self.isMonster && !self.isYeti) {
			// Monster just bounces off boundaries
			if (self.y > 2732 - 150) {
				self.y = 2732 - 150;
				self.velocity = -Math.abs(self.velocity);
			}
			if (self.y < 50) {
				self.y = 50;
				self.velocity = Math.abs(self.velocity);
			}
		} else if (self.isYeti) {
			// Yeti stays on ground but can jump
			if (self.y > 2732 - 150) {
				self.y = 2732 - 150;
				if (self.velocity > 0) {
					// Only reset velocity if falling down
					self.velocity = 0;
				}
				self.isOnGround = true;
			}
			if (self.y < 50) {
				self.y = 50;
				self.velocity = Math.abs(self.velocity);
			}
		}
	};
	return self;
});
var Pipe = Container.expand(function () {
	var self = Container.call(this);
	self.gapSize = 1200; // Increased gap size for easier navigation
	self.speed = -2;
	self.scored = false;
	// Create top pipe
	self.topPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 1
	});
	// Create bottom pipe
	self.bottomPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 0
	});
	self.setGapPosition = function (gapY) {
		self.topPipe.y = gapY - self.gapSize / 2;
		self.bottomPipe.y = gapY + self.gapSize / 2;
	};
	self.update = function () {
		self.x += self.speed;
		// Check if bird passed through pipe
		if (!self.scored && self.x < bird.x) {
			self.scored = true;
			LK.setScore(LK.getScore() + 1);
			scoreTxt.setText(LK.getScore());
			LK.getSound('score').play();
		}
	};
	return self;
});
var SnowParticle = Container.expand(function () {
	var self = Container.call(this);
	var snowGraphics = self.attachAsset('wing', {
		anchorX: 0.5,
		anchorY: 0.5,
		scaleX: 0.3,
		scaleY: 0.3,
		tint: 0xFFFFFF
	});
	self.speed = Math.random() * 2 + 1;
	self.drift = Math.random() * 0.5 - 0.25;
	self.update = function () {
		self.y += self.speed;
		self.x += self.drift;
		if (self.y > 2732) {
			self.y = -50;
			self.x = Math.random() * 2048;
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x87CEEB
});

/**** 
* Game Code
****/ 
var bird;
var pipes = [];
var ground;
var scoreTxt;
var gameOver = false;
var gameStarted = false;
var pipeSpawnTimer = 0;
var pipeSpawnInterval = 240; // frames between pipe spawns - increased gap
var hasTransformedToMonster = false;
var mountainBackground;
var snowParticles = [];
var isWinterActive = false;
// Create ground
ground = game.addChild(LK.getAsset('ground', {
	anchorX: 0,
	anchorY: 1,
	x: 0,
	y: 2732
}));
// Create bird
bird = game.addChild(new Bird());
bird.x = 300;
bird.y = 2732 / 2;
// Create score text
scoreTxt = new Text2('0', {
	size: 80,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
scoreTxt.y = 100;
// Create instruction text
var instructionTxt = new Text2('TAP TO START', {
	size: 60,
	fill: 0xFFFFFF
});
instructionTxt.anchor.set(0.5, 0.5);
LK.gui.center.addChild(instructionTxt);
var pipePatternIndex = 0;
var pipePositions = [800, 1000, 1200, 1400, 1600, 1800, 1600, 1400, 1200, 1000]; // Connected systematic pattern
function spawnPipe() {
	var pipe = new Pipe();
	pipe.x = 2048 + 60;
	// Use systematic pattern with smooth transitions
	var gapY = pipePositions[pipePatternIndex % pipePositions.length];
	pipePatternIndex++;
	pipe.setGapPosition(gapY);
	pipes.push(pipe);
	game.addChild(pipe);
}
function checkCollisions() {
	// Monster and yeti are invincible and can fly through pipes
	if (bird.isMonster || bird.isYeti) {
		return;
	}
	for (var i = 0; i < pipes.length; i++) {
		var pipe = pipes[i];
		// Check collision with top pipe
		if (bird.intersects(pipe.topPipe)) {
			gameOver = true;
			LK.getSound('hit').play();
			return;
		}
		// Check collision with bottom pipe
		if (bird.intersects(pipe.bottomPipe)) {
			gameOver = true;
			LK.getSound('hit').play();
			return;
		}
	}
}
function checkSeasonChange() {
	// Winter season at 25 points
	if (LK.getScore() >= 25) {
		game.setBackgroundColor(0xF0F8FF); // Winter white/light blue
		// Add Mount Everest background once
		if (!isWinterActive) {
			isWinterActive = true;
			// Transform bird to yeti for winter
			bird.transformToYeti();
			// Add mountain background
			mountainBackground = game.addChild(LK.getAsset('mountain', {
				anchorX: 0.5,
				anchorY: 1,
				x: 1024,
				y: 2732 - 100
			}));
			// Send mountain to back
			game.setChildIndex(mountainBackground, 0);
			// Create snow particles
			for (var i = 0; i < 50; i++) {
				var snow = new SnowParticle();
				snow.x = Math.random() * 2048;
				snow.y = Math.random() * 2732;
				snowParticles.push(snow);
				game.addChild(snow);
			}
		}
	} else if (LK.getScore() >= 5) {
		// Change to night theme when score reaches 5
		game.setBackgroundColor(0x1a1a2e); // Dark night blue
		// Transform bird to monster once when reaching night time
		if (!hasTransformedToMonster) {
			hasTransformedToMonster = true;
			bird.transformToMonster();
		}
	} else {
		game.setBackgroundColor(0x87CEEB); // Day sky blue
	}
}
function cleanupPipes() {
	for (var i = pipes.length - 1; i >= 0; i--) {
		var pipe = pipes[i];
		if (pipe.x < -100) {
			pipe.destroy();
			pipes.splice(i, 1);
		}
	}
}
game.down = function (x, y, obj) {
	if (gameOver) {
		return;
	}
	if (!gameStarted) {
		gameStarted = true;
		instructionTxt.visible = false;
	}
	bird.flap();
};
game.update = function () {
	if (gameOver) {
		LK.showGameOver();
		return;
	}
	if (!gameStarted) {
		return;
	}
	// Update bird
	// Spawn pipes
	pipeSpawnTimer++;
	if (pipeSpawnTimer >= pipeSpawnInterval) {
		spawnPipe();
		pipeSpawnTimer = 0;
	}
	// Check collisions
	checkCollisions();
	// Check for season changes
	checkSeasonChange();
	// Cleanup off-screen pipes
	cleanupPipes();
	// Update snow particles if winter is active
	if (isWinterActive) {
		for (var i = 0; i < snowParticles.length; i++) {
			snowParticles[i].update();
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -185,9 +185,12 @@
 		} else if (self.isYeti) {
 			// Yeti stays on ground but can jump
 			if (self.y > 2732 - 150) {
 				self.y = 2732 - 150;
-				self.velocity = 0;
+				if (self.velocity > 0) {
+					// Only reset velocity if falling down
+					self.velocity = 0;
+				}
 				self.isOnGround = true;
 			}
 			if (self.y < 50) {
 				self.y = 50;