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

/**** 
* Classes
****/ 
var Ball = Container.expand(function (value) {
	var self = Container.call(this);
	self.value = value || 2;
	self.velocityX = 0;
	self.velocityY = 0;
	self.gravity = 0.8;
	self.bounce = 0.4;
	self.friction = 0.98;
	self.radius = 60;
	self.isStatic = false;
	self.mergeTimer = 0;
	self.hasBeenMerged = false;
	var ballAsset = self.attachAsset('ball' + self.value, {
		anchorX: 0.5,
		anchorY: 0.5
	});
	var valueText = new Text2(self.value.toString(), {
		size: 42,
		fill: 0xFFFFFF
	});
	valueText.anchor.set(0.5, 0.5);
	self.addChild(valueText);
	self.update = function () {
		if (self.hasBeenMerged) return;
		if (self.mergeTimer > 0) {
			self.mergeTimer--;
			return;
		}
		if (!self.isStatic) {
			// Apply gravity to velocity
			self.velocityY += self.gravity;
			// Store current position as backup
			var originalX = self.x;
			var originalY = self.y;
			// Calculate intended new position
			var intendedX = self.x + self.velocityX;
			var intendedY = self.y + self.velocityY;
			// Check boundary constraints first and adjust intended position
			var localWidth = gameAreaRight - gameAreaLeft;
			var localBottom = gameAreaHeight - 20; // gameAreaHeight minus bottom wall height
			// Wall collision checks with intended position
			if (intendedX - self.radius < 0) {
				intendedX = self.radius;
				self.velocityX *= -self.bounce;
			}
			if (intendedX + self.radius > localWidth) {
				intendedX = localWidth - self.radius;
				self.velocityX *= -self.bounce;
			}
			// Ground collision with intended position
			if (intendedY + self.radius > localBottom) {
				intendedY = localBottom - self.radius;
				self.velocityY *= -self.bounce;
				self.velocityX *= self.friction;
				if (Math.abs(self.velocityY) < 1) {
					self.velocityY = 0;
					self.isStatic = true;
				}
			}
			// Check for ball-to-ball collisions with intended position
			var canMoveSafely = true;
			for (var i = 0; i < balls.length; i++) {
				var otherBall = balls[i];
				if (otherBall === self || otherBall.hasBeenMerged) continue;
				// Calculate distance at intended position
				var dx = otherBall.x - intendedX;
				var dy = otherBall.y - intendedY;
				var distance = Math.sqrt(dx * dx + dy * dy);
				var minDistance = self.radius + otherBall.radius;
				// Check if moving to intended position would cause overlap
				if (distance < minDistance) {
					// Check for merge first
					if (self.value === otherBall.value && self.mergeTimer === 0 && otherBall.mergeTimer === 0) {
						// Merge balls
						var newValue = self.value * 2;
						if (newValue <= 2048) {
							var newBall = new Ball(newValue);
							newBall.x = (self.x + otherBall.x) / 2;
							newBall.y = (self.y + otherBall.y) / 2;
							newBall.velocityX = (self.velocityX + otherBall.velocityX) / 2;
							newBall.velocityY = (self.velocityY + otherBall.velocityY) / 2;
							newBall.mergeTimer = 10;
							balls.push(newBall);
							gameArea.addChild(newBall);
							// Mark for removal
							self.hasBeenMerged = true;
							otherBall.hasBeenMerged = true;
							LK.getSound('merge').play();
							LK.setScore(LK.getScore() + newValue);
							scoreText.setText(LK.getScore());
							// Check win condition
							if (newValue === 2048) {
								LK.showYouWin();
							}
							return;
						}
					}
					// Collision will occur, prevent movement and apply collision response
					canMoveSafely = false;
					// Calculate collision normal
					var normalX = dx / distance;
					var normalY = dy / distance;
					// Calculate relative velocity
					var relativeVelX = self.velocityX - otherBall.velocityX;
					var relativeVelY = self.velocityY - otherBall.velocityY;
					// Calculate collision speed along normal
					var speed = relativeVelX * normalX + relativeVelY * normalY;
					// Only resolve if objects are moving towards each other
					if (speed > 0) {
						// Calculate collision impulse
						var impulse = 2 * speed / 2; // Assume equal mass
						var impulseX = impulse * normalX * 0.8; // Add damping factor
						var impulseY = impulse * normalY * 0.8;
						// Apply impulse
						self.velocityX -= impulseX;
						self.velocityY -= impulseY;
						otherBall.velocityX += impulseX;
						otherBall.velocityY += impulseY;
						// Apply friction
						self.velocityX *= self.friction;
						self.velocityY *= self.friction;
						otherBall.velocityX *= otherBall.friction;
						otherBall.velocityY *= otherBall.friction;
					}
					// If balls are currently overlapping, separate them
					var currentDx = otherBall.x - self.x;
					var currentDy = otherBall.y - self.y;
					var currentDistance = Math.sqrt(currentDx * currentDx + currentDy * currentDy);
					if (currentDistance < minDistance && currentDistance > 0) {
						var overlap = minDistance - currentDistance;
						var separationX = currentDx / currentDistance * overlap * 0.6;
						var separationY = currentDy / currentDistance * overlap * 0.6;
						self.x -= separationX;
						self.y -= separationY;
						otherBall.x += separationX;
						otherBall.y += separationY;
						// Ensure balls stay within bounds after separation
						self.x = Math.max(self.radius, Math.min(localWidth - self.radius, self.x));
						self.y = Math.max(self.radius, Math.min(localBottom - self.radius, self.y));
						otherBall.x = Math.max(otherBall.radius, Math.min(localWidth - otherBall.radius, otherBall.x));
						otherBall.y = Math.max(otherBall.radius, Math.min(localBottom - otherBall.radius, otherBall.y));
					}
					break; // Stop checking other balls for this frame
				}
			}
			// Only update position if it's safe to do so
			if (canMoveSafely) {
				self.x = intendedX;
				self.y = intendedY;
			}
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x34495e
});

/**** 
* Game Code
****/ 
var balls = [];
var nextBallValue = 2;
var gameAreaLeft = 224;
var gameAreaRight = 1824;
var gameAreaTop = 400;
var gameAreaBottom = 2600;
var dropCooldown = 0;
var gameAreaHeight = gameAreaBottom - gameAreaTop;
// Create game area background
var gameAreaBg = game.addChild(LK.getAsset('gameArea', {
	anchorX: 0.5,
	anchorY: 0,
	x: 1024,
	y: gameAreaTop
}));
// Create game area container for balls
var gameArea = new Container();
gameArea.x = gameAreaLeft;
gameArea.y = gameAreaTop;
game.addChild(gameArea);
// Create visible walls
var leftWall = game.addChild(LK.getAsset('leftWall', {
	anchorX: 1,
	anchorY: 0,
	x: gameAreaLeft,
	y: gameAreaTop
}));
var rightWall = game.addChild(LK.getAsset('rightWall', {
	anchorX: 0,
	anchorY: 0,
	x: gameAreaRight,
	y: gameAreaTop
}));
var bottomWall = game.addChild(LK.getAsset('bottomWall', {
	anchorX: 0.5,
	anchorY: 0,
	x: 1024,
	y: gameAreaBottom
}));
// Create danger zone indicator
var dangerZone = game.addChild(LK.getAsset('dangerZone', {
	anchorX: 0.5,
	anchorY: 0,
	x: 1024,
	y: gameAreaTop,
	alpha: 0.3
}));
// Create game over line
var gameOverLine = game.addChild(LK.getAsset('gameOverLine', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 1024,
	y: gameAreaTop + 100
}));
// Create score display
var scoreText = new Text2('0', {
	size: 80,
	fill: 0xFFFFFF
});
scoreText.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreText);
scoreText.y = 100;
// Create next ball preview
var nextBallPreview = LK.getAsset('ball' + nextBallValue, {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 1024,
	y: 300,
	scaleX: 0.75,
	scaleY: 0.75
});
game.addChild(nextBallPreview);
// Create next ball value text
var nextBallText = new Text2(nextBallValue.toString(), {
	size: 24,
	fill: 0xFFFFFF
});
nextBallText.anchor.set(0.5, 0.5);
nextBallText.x = 1024;
nextBallText.y = 300;
game.addChild(nextBallText);
// Create instruction text
var instructionText = new Text2('Tap to drop ball', {
	size: 40,
	fill: 0xFFFFFF
});
instructionText.anchor.set(0.5, 0);
instructionText.x = 1024;
instructionText.y = 150;
game.addChild(instructionText);
function getRandomNextBallValue() {
	var values = [2, 4, 8];
	return values[Math.floor(Math.random() * values.length)];
}
function updateNextBallPreview() {
	game.removeChild(nextBallPreview);
	game.removeChild(nextBallText);
	nextBallPreview = LK.getAsset('ball' + nextBallValue, {
		anchorX: 0.5,
		anchorY: 0.5,
		x: 1024,
		y: 300,
		scaleX: 0.75,
		scaleY: 0.75
	});
	game.addChild(nextBallPreview);
	nextBallText = new Text2(nextBallValue.toString(), {
		size: 24,
		fill: 0xFFFFFF
	});
	nextBallText.anchor.set(0.5, 0.5);
	nextBallText.x = 1024;
	nextBallText.y = 300;
	game.addChild(nextBallText);
}
function checkGameOver() {
	for (var i = 0; i < balls.length; i++) {
		// Check if ball touches the danger zone (first 100 pixels of game area)
		// Since balls are in gameArea container, we use local coordinates
		// Only trigger game over if ball is static (not actively falling) and in danger zone
		if (balls[i].y - balls[i].radius <= 100 && balls[i].isStatic) {
			LK.showGameOver();
			return;
		}
	}
}
function cleanupMergedBalls() {
	for (var i = balls.length - 1; i >= 0; i--) {
		if (balls[i].hasBeenMerged) {
			gameArea.removeChild(balls[i]);
			balls[i].destroy();
			balls.splice(i, 1);
		}
	}
}
game.down = function (x, y, obj) {
	if (dropCooldown > 0) return;
	// Constrain drop position to game area (convert to local coordinates)
	var localWidth = gameAreaRight - gameAreaLeft;
	var localX = x - gameAreaLeft;
	var dropX = Math.max(60, Math.min(localWidth - 60, localX));
	var newBall = new Ball(nextBallValue);
	newBall.x = dropX;
	newBall.y = 170; // Start below the danger zone (100px) plus ball radius (60px) plus buffer
	newBall.velocityX = 0;
	newBall.velocityY = 0;
	balls.push(newBall);
	gameArea.addChild(newBall);
	LK.getSound('drop').play();
	// Update next ball
	nextBallValue = getRandomNextBallValue();
	updateNextBallPreview();
	dropCooldown = 30; // 0.5 seconds at 60fps
};
game.update = function () {
	if (dropCooldown > 0) {
		dropCooldown--;
	}
	// Multi-pass collision resolution to handle complex scenarios
	for (var pass = 0; pass < 3; pass++) {
		var hasCollisions = false;
		for (var i = 0; i < balls.length; i++) {
			var ball1 = balls[i];
			if (ball1.hasBeenMerged) continue;
			for (var j = i + 1; j < balls.length; j++) {
				var ball2 = balls[j];
				if (ball2.hasBeenMerged) continue;
				var dx = ball2.x - ball1.x;
				var dy = ball2.y - ball1.y;
				var distance = Math.sqrt(dx * dx + dy * dy);
				var minDistance = ball1.radius + ball2.radius;
				// If balls are overlapping, separate them
				if (distance < minDistance && distance > 0) {
					hasCollisions = true;
					var overlap = minDistance - distance;
					var separationX = dx / distance * overlap * 0.5;
					var separationY = dy / distance * overlap * 0.5;
					// Only separate if balls are not in merge process
					if (ball1.mergeTimer === 0 && ball2.mergeTimer === 0) {
						ball1.x -= separationX;
						ball1.y -= separationY;
						ball2.x += separationX;
						ball2.y += separationY;
						// Ensure balls stay within bounds
						var localWidth = gameAreaRight - gameAreaLeft;
						var localBottom = gameAreaHeight - 20;
						ball1.x = Math.max(ball1.radius, Math.min(localWidth - ball1.radius, ball1.x));
						ball1.y = Math.max(ball1.radius, Math.min(localBottom - ball1.radius, ball1.y));
						ball2.x = Math.max(ball2.radius, Math.min(localWidth - ball2.radius, ball2.x));
						ball2.y = Math.max(ball2.radius, Math.min(localBottom - ball2.radius, ball2.y));
						// Dampen velocities to prevent oscillation
						ball1.velocityX *= 0.9;
						ball1.velocityY *= 0.9;
						ball2.velocityX *= 0.9;
						ball2.velocityY *= 0.9;
					}
				}
			}
		}
		// If no collisions detected in this pass, we can stop early
		if (!hasCollisions) break;
	}
	cleanupMergedBalls();
	checkGameOver();
	// Update score display
	scoreText.setText(LK.getScore());
};