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

/**** 
* Classes
****/ 
// LetterBubble: A bubble with a letter inside, touchable
var LetterBubble = Container.expand(function () {
	var self = Container.call(this);
	// Properties to be set after creation:
	// self.letter (string, e.g. "A")
	// self.isTarget (bool, is this the correct letter to pop?)
	// We'll assign a color randomly from the available bubble assets
	// Pick a random bubble color asset for the background
	var bubbleAssetIds = ['bubbleBlue', 'bubbleGreen', 'bubbleRed', 'bubbleYellow', 'bubblePurple', 'bubbleOrange'];
	var bubbleIdx = Math.floor(Math.random() * bubbleAssetIds.length);
	self.bubbleBg = LK.getAsset(bubbleAssetIds[bubbleIdx], {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.addChild(self.bubbleBg);
	// Letter color should contrast with bubble color for readability
	self.letterText = new Text2('A', {
		size: 120,
		fill: 0xFFFFFF,
		font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
	});
	self.letterText.anchor.set(0.5, 0.5);
	// Add a subtle drop shadow for pop
	self.letterText.setStyle({
		dropShadow: true,
		dropShadowColor: "#222",
		dropShadowBlur: 8,
		dropShadowDistance: 4
	});
	self.addChild(self.letterText);
	// Animate in (pop effect)
	self.scale.set(0.1, 0.1);
	tween(self.scale, {
		x: 1,
		y: 1
	}, {
		duration: 300,
		easing: tween.elasticOut
	});
	// Touch event
	self.down = function (x, y, obj) {
		// Only allow popping if not already popped
		if (self.popped) {
			return;
		}
		self.popped = true;
		onBubbleTapped(self);
	};
	// Pop animation
	self.pop = function (_onFinish) {
		// Play pop sound
		LK.getSound('pop').play();
		// Animate: scale up, fade out, then destroy
		tween(self.scale, {
			x: 1.3,
			y: 1.3
		}, {
			duration: 120,
			easing: tween.easeOut
		});
		tween(self, {
			alpha: 0
		}, {
			duration: 180,
			delay: 100,
			onFinish: function onFinish() {
				if (_onFinish) {
					_onFinish();
				}
				self.destroy();
			}
		});
	};
	// Gentle shake for incorrect
	self.shake = function () {
		// Animate left-right shake
		var origX = self.x;
		tween(self, {
			x: origX - 20
		}, {
			duration: 60,
			easing: tween.easeIn,
			onFinish: function onFinish() {
				tween(self, {
					x: origX + 20
				}, {
					duration: 60,
					easing: tween.easeOut,
					onFinish: function onFinish() {
						tween(self, {
							x: origX
						}, {
							duration: 60
						});
					}
				});
			}
		});
	};
	return self;
});
// ZigzagLetterBubble: A harder bubble with zigzag movement and faded color
var ZigzagLetterBubble = Container.expand(function () {
	var self = Container.call(this);
	// Properties to be set after creation:
	// self.letter (string)
	// self.isTarget (bool)
	// Pick a faded color bubble (use alpha)
	var bubbleAssetIds = ['bubbleBlue', 'bubbleGreen', 'bubbleRed', 'bubbleYellow', 'bubblePurple', 'bubbleOrange'];
	var bubbleIdx = Math.floor(Math.random() * bubbleAssetIds.length);
	self.bubbleBg = LK.getAsset(bubbleAssetIds[bubbleIdx], {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.bubbleBg.alpha = 0.45 + Math.random() * 0.25; // faded look
	self.addChild(self.bubbleBg);
	// Letter text, more faded
	self.letterText = new Text2('A', {
		size: 120,
		fill: 0xFFFFFF,
		font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
	});
	self.letterText.anchor.set(0.5, 0.5);
	self.letterText.alpha = 0.7;
	self.letterText.setStyle({
		dropShadow: true,
		dropShadowColor: "#222",
		dropShadowBlur: 8,
		dropShadowDistance: 4
	});
	self.addChild(self.letterText);
	// Animate in (pop effect)
	self.scale.set(0.1, 0.1);
	tween(self.scale, {
		x: 1,
		y: 1
	}, {
		duration: 300,
		easing: tween.elasticOut
	});
	// Zigzag movement parameters
	self._zigzagPhase = Math.random() * Math.PI * 2;
	self._zigzagSpeed = 0.015 + Math.random() * 0.01; // radians per tick
	self._zigzagAmp = 30 + Math.random() * 30; // amplitude in px
	self._zigzagBaseX = 0; // will be set on placement
	// Touch event
	self.down = function (x, y, obj) {
		if (self.popped) {
			return;
		}
		self.popped = true;
		onBubbleTapped(self);
	};
	// Pop animation
	self.pop = function (_onFinish) {
		LK.getSound('pop').play();
		tween(self.scale, {
			x: 1.3,
			y: 1.3
		}, {
			duration: 120,
			easing: tween.easeOut
		});
		tween(self, {
			alpha: 0
		}, {
			duration: 180,
			delay: 100,
			onFinish: function onFinish() {
				if (_onFinish) {
					_onFinish();
				}
				self.destroy();
			}
		});
	};
	// Gentle shake for incorrect
	self.shake = function () {
		var origX = self.x;
		tween(self, {
			x: origX - 20
		}, {
			duration: 60,
			easing: tween.easeIn,
			onFinish: function onFinish() {
				tween(self, {
					x: origX + 20
				}, {
					duration: 60,
					easing: tween.easeOut,
					onFinish: function onFinish() {
						tween(self, {
							x: origX
						}, {
							duration: 60
						});
					}
				});
			}
		});
	};
	// Zigzag update
	self.update = function () {
		if (typeof self._zigzagBaseX === "number") {
			self._zigzagPhase += self._zigzagSpeed;
			self.x = self._zigzagBaseX + Math.sin(self._zigzagPhase) * self._zigzagAmp;
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0xE3F6FD // Light blue background for kid-friendly look
});

/**** 
* Game Code
****/ 
// Alphabet array
// Letter bubbles: We'll use colored ellipses for bubbles, and overlay Text2 for letters.
// We'll use 26 different colors for variety, but for MVP, 5-6 colors are enough and can be reused.
// Sounds for correct/incorrect feedback
// Simple celebratory sound for win
var alphabet = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
// Game state
var selectedGameMode = "endless"; // "endless", "timed", or "hard"
var currentLetterIdx = 0; // Index in alphabet for the current target letter
var bubbles = []; // Array of LetterBubble instances
var lettersPerRound = 4; // Start with 4, will increase as player gets correct answers
var correctInARow = 0; // Track correct answers in a row for difficulty
var roundActive = false; // Is a round currently active?
var score = 0; // Number of correct letters popped
// Endless mode: after all letters, reshuffle and continue
var endlessMode = true;
// Timer variables
var timerActive = false;
var timerValue = 0; // seconds left
var timerInterval = null;
var TIMER_START = 310; // seconds to start with when timer mode begins
var TIMER_ADD = 3; // seconds to add per correct answer
// High score
var highScore = storage.letterpop_highscore || 0;
// UI elements
var promptText = new Text2('', {
	size: 110,
	fill: 0x333333,
	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
});
promptText.anchor.set(0.5, 0);
promptText.y = 90; // Move prompt lower from the very top
LK.gui.top.addChild(promptText);
var scoreText = new Text2('0', {
	size: 110,
	fill: 0x4A90E2,
	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
});
scoreText.anchor.set(0.5, 1);
scoreText.y = -120; // Move it higher above the very bottom
LK.gui.bottom.addChild(scoreText);
// High score text (top center, under prompt)
var highScoreText = new Text2('High Score: ' + highScore, {
	size: 60,
	fill: 0x888888,
	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
});
highScoreText.anchor.set(0.5, 0);
highScoreText.y = 240; // Add more spacing below the promptText
LK.gui.top.addChild(highScoreText);
// Timer text (placed just above the score)
var timerText = new Text2('', {
	size: 80,
	fill: 0xD0021B,
	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
});
timerText.anchor.set(0.5, 1);
// We'll position timerText just above the score
timerText.y = scoreText.y - 100;
LK.gui.bottom.addChild(timerText);
// Timer change effect (shows +2s/-1s)
var timerChangeText = new Text2('', {
	size: 70,
	fill: 0x43A047,
	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
});
timerChangeText.anchor.set(0.5, 1);
timerChangeText.alpha = 0;
timerChangeText.y = timerText.y - 60;
LK.gui.bottom.addChild(timerChangeText);
// Helper to show timer change effect
function showTimerChangeEffect(text, color) {
	timerChangeText.setText(text);
	timerChangeText.setStyle({
		fill: color
	});
	timerChangeText.alpha = 0;
	timerChangeText.y = timerText.y - 80;
	tween(timerChangeText, {
		alpha: 1,
		y: timerChangeText.y - 40
	}, {
		duration: 200,
		onFinish: function onFinish() {
			LK.setTimeout(function () {
				tween(timerChangeText, {
					alpha: 0
				}, {
					duration: 300
				});
			}, 400);
		}
	});
}
// Feedback text (centered, fades in/out)
var feedbackText = new Text2('', {
	size: 130,
	fill: 0x43A047,
	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
});
feedbackText.anchor.set(0.5, 0.5);
feedbackText.alpha = 0;
LK.gui.center.addChild(feedbackText);
// Helper: Shuffle array (Fisher-Yates)
function shuffleArray(arr) {
	var a = arr.slice();
	for (var i = a.length - 1; i > 0; i--) {
		var j = Math.floor(Math.random() * (i + 1));
		var t = a[i];
		a[i] = a[j];
		a[j] = t;
	}
	return a;
}
// Helper: Start a new round
function startRound() {
	// Remove old bubbles
	for (var i = 0; i < bubbles.length; i++) {
		bubbles[i].destroy();
	}
	bubbles = [];
	if (currentLetterIdx >= alphabet.length) {
		if (endlessMode) {
			// Reshuffle for endless play, keep score and difficulty
			currentLetterIdx = 0;
			// Shuffle alphabet for next endless cycle
			alphabet = shuffleArray(alphabet);
		} else {
			// All letters done!
			showCelebration();
			return;
		}
	}
	roundActive = true;
	// Set prompt
	var targetLetter = alphabet[currentLetterIdx];
	promptText.setText("Find: " + targetLetter);
	// Pick distractor letters (not the target)
	var distractors = [];
	var pool = [];
	for (var i = 0; i < alphabet.length; i++) {
		if (i !== currentLetterIdx) {
			pool.push(alphabet[i]);
		}
	}
	pool = shuffleArray(pool);
	for (var i = 0; i < lettersPerRound - 1; i++) {
		distractors.push(pool[i]);
	}
	// Combine and shuffle
	var roundLetters = distractors.concat([targetLetter]);
	roundLetters = shuffleArray(roundLetters);
	// Dynamically arrange bubbles in a centered grid, scaling and spacing to fit up to 20 bubbles
	var numBubbles = roundLetters.length;
	var maxBubbles = 20;
	var minBubbleSize = 110;
	var maxBubbleSize = 300;
	var minMargin = 24;
	var maxMargin = 60;
	// Calculate grid: try to make it as square as possible
	var cols = Math.ceil(Math.sqrt(numBubbles));
	var rows = Math.ceil(numBubbles / cols);
	// Compute available width/height (leave some padding)
	var padX = 80,
		padY = 200;
	var availW = 2048 - padX * 2;
	var availH = 1800 - padY * 2; // keep bubbles in upper 2/3 of screen
	// Compute max bubble size that fits
	var bubbleSizeW = Math.floor((availW - (cols - 1) * minMargin) / cols);
	var bubbleSizeH = Math.floor((availH - (rows - 1) * minMargin) / rows);
	var bubbleSize = Math.max(minBubbleSize, Math.min(maxBubbleSize, Math.min(bubbleSizeW, bubbleSizeH)));
	// Compute margin to center bubbles
	var marginX = Math.max(minMargin, Math.min(maxMargin, Math.floor((availW - cols * bubbleSize) / Math.max(1, cols - 1))));
	var marginY = Math.max(minMargin, Math.min(maxMargin, Math.floor((availH - rows * bubbleSize) / Math.max(1, rows - 1))));
	// Compute grid start
	var totalGridW = cols * bubbleSize + (cols - 1) * marginX;
	var totalGridH = rows * bubbleSize + (rows - 1) * marginY;
	// Vertically center grid in the middle of the screen, but never closer than 200px to the top
	// 2732 is the screen height. Center the grid, but keep at least 200px from the top and 200px from the bottom.
	var minTop = 200;
	var minBottom = 200;
	var availableHeight = 2732 - minTop - minBottom;
	var gridTop = minTop + Math.max(0, (availableHeight - totalGridH) / 2);
	var startX = (2048 - totalGridW) / 2 + bubbleSize / 2;
	var startY = gridTop + bubbleSize / 2;
	// Place bubbles in grid
	var positions = [];
	for (var i = 0; i < numBubbles; i++) {
		var row = Math.floor(i / cols);
		var col = i % cols;
		positions.push({
			x: startX + col * (bubbleSize + marginX),
			y: startY + row * (bubbleSize + marginY)
		});
	}
	// Timer text is now statically positioned above the score in LK.gui.bottom
	// Create and add bubbles, scale them to fit
	for (var i = 0; i < roundLetters.length; i++) {
		var useZigzag = false;
		// Hard mode: all bubbles are zigzag/faded
		if (typeof selectedGameMode !== "undefined" && selectedGameMode === "hard") {
			useZigzag = true;
		} else {
			// Timed/Endless: introduce zigzag as difficulty increases
			if (roundLetters.length >= 7) {
				var zigzagCount = Math.floor((roundLetters.length - 6) * 0.7);
				if (i < zigzagCount) {
					useZigzag = true;
				}
			}
		}
		var bubble;
		if (useZigzag) {
			bubble = new ZigzagLetterBubble();
		} else {
			bubble = new LetterBubble();
		}
		bubble.letter = roundLetters[i];
		bubble.letterText.setText(bubble.letter);
		bubble.isTarget = bubble.letter === targetLetter;
		// Position
		bubble.x = positions[i].x;
		bubble.y = positions[i].y;
		// For zigzag, set baseX for zigzag movement
		if (useZigzag) {
			bubble._zigzagBaseX = bubble.x;
		}
		// Scale bubble to fit
		var scale = bubbleSize / 300; // 300 is the asset's base size
		bubble.scale.set(scale, scale);
		// Also scale letter text for readability
		bubble.letterText.setStyle({
			size: Math.floor(120 * scale)
		});
		// Add to game
		game.addChild(bubble);
		bubbles.push(bubble);
	}
}
// Handle bubble tap
function onBubbleTapped(bubble) {
	if (!roundActive) {
		return;
	}
	if (bubble.isTarget) {
		// Correct!
		roundActive = false;
		score++;
		scoreText.setText(score);
		// Update high score if needed
		if (score > highScore) {
			highScore = score;
			highScoreText.setText('High Score: ' + highScore);
			storage.letterpop_highscore = highScore;
		}
		// Start timer mode after 10 points (only in Timed Mode)
		if (selectedGameMode === "timed" && !timerActive && score >= 10) {
			timerActive = true;
			timerValue = TIMER_START;
			timerText.setText('Time: ' + timerValue);
			if (timerInterval) {
				LK.clearInterval(timerInterval);
			}
			timerInterval = LK.setInterval(function () {
				if (!timerActive) {
					return;
				}
				timerValue--;
				timerText.setText('Time: ' + timerValue);
				if (timerValue <= 0) {
					timerValue = 0;
					timerText.setText('Time: 0');
					endGameTimeout();
				}
			}, 1000);
		}
		// Add time for correct answer if timer is active
		if (timerActive) {
			timerValue += 2;
			timerText.setText('Time: ' + timerValue);
			showTimerChangeEffect("+2s", "#43A047");
		}
		// Track correct answers in a row for difficulty increase
		if (typeof correctInARow === "undefined") {
			correctInARow = 0;
		}
		correctInARow++;
		// After every two correct answers, increase number of options (up to 20)
		if (correctInARow % 2 === 0) {
			if (typeof lettersPerRound === "undefined") {
				lettersPerRound = 4;
			}
			lettersPerRound = Math.min(lettersPerRound + 1, 20);
		}
		// Feedback
		showFeedback("Great!", "#43A047");
		LK.getSound('ding').play();
		// Pop animation, then next round
		bubble.pop(function () {
			// Remove other bubbles with fade out
			for (var i = 0; i < bubbles.length; i++) {
				if (bubbles[i] !== bubble) {
					tween(bubbles[i], {
						alpha: 0
					}, {
						duration: 200,
						onFinish: function (bub) {
							return function () {
								bub.destroy();
							};
						}(bubbles[i])
					});
				}
			}
			// Next letter after short delay
			LK.setTimeout(function () {
				currentLetterIdx++;
				startRound();
			}, 600);
		});
	} else {
		// Reset streak on incorrect answer
		correctInARow = 0;
		// Incorrect
		showFeedback("Try again!", "#D0021B");
		LK.getSound('oops').play();
		bubble.shake();
		// Subtract 1s for wrong answer if timer is active
		if (timerActive) {
			timerValue = Math.max(0, timerValue - 1);
			timerText.setText('Time: ' + timerValue);
			showTimerChangeEffect("-1s", "#D0021B");
			if (timerValue <= 0) {
				timerValue = 0;
				timerText.setText('Time: 0');
				endGameTimeout();
			}
		}
		// Allow another try (do not end round)
	}
}
// Show feedback text in center, fade in/out
function showFeedback(msg, color) {
	feedbackText.setText(msg);
	// Use setStyle to update fill color safely
	feedbackText.setStyle({
		fill: color
	});
	feedbackText.alpha = 0;
	tween(feedbackText, {
		alpha: 1
	}, {
		duration: 120,
		onFinish: function onFinish() {
			LK.setTimeout(function () {
				tween(feedbackText, {
					alpha: 0
				}, {
					duration: 200
				});
			}, 500);
		}
	});
}
// End game due to timer running out
function endGameTimeout() {
	timerActive = false;
	if (timerInterval) {
		LK.clearInterval(timerInterval);
		timerInterval = null;
	}
	// Remove any remaining bubbles
	for (var i = 0; i < bubbles.length; i++) {
		bubbles[i].destroy();
	}
	bubbles = [];
	promptText.setText("Time's up!");
	feedbackText.setText("Score: " + score);
	feedbackText.setStyle({
		fill: 0xD0021B
	});
	feedbackText.alpha = 0;
	tween(feedbackText, {
		alpha: 1
	}, {
		duration: 300
	});
	// Play oops sound
	LK.getSound('oops').play();
	// Show game over after a short delay (triggers LK's game over popup)
	LK.setTimeout(function () {
		LK.showGameOver();
	}, 1200);
}
// Show celebration screen
function showCelebration() {
	// Remove any remaining bubbles
	for (var i = 0; i < bubbles.length; i++) {
		bubbles[i].destroy();
	}
	bubbles = [];
	promptText.setText("All done!");
	feedbackText.setText("You did it!");
	// Use setStyle to update fill color safely
	feedbackText.setStyle({
		fill: 0xF5A623
	});
	feedbackText.alpha = 0;
	tween(feedbackText, {
		alpha: 1
	}, {
		duration: 300
	});
	// Play cheer sound
	LK.getSound('cheer').play();
	// Show "You Win" after a short delay (triggers LK's win popup)
	LK.setTimeout(function () {
		LK.showYouWin();
	}, 1200);
}
// Start game
function startGame() {
	// Show a visually appealing home screen before the first round
	if (typeof startGame.hasRun === "undefined") {
		var isFarFromOthers = function isFarFromOthers(x, y, minDist) {
			for (var i = 0; i < placedPositions.length; i++) {
				var dx = x - placedPositions[i].x;
				var dy = y - placedPositions[i].y;
				if (Math.sqrt(dx * dx + dy * dy) < minDist) {
					return false;
				}
			}
			return true;
		};
		// Only show on first load, not after game over
		startGame.hasRun = true;
		// Create a custom home screen container
		var homeScreen = new Container();
		// Big colorful title
		var title = new Text2("Letter Pop!", {
			size: 220,
			fill: ["#4A90E2", "#F5A623", "#7ED321", "#D0021B"],
			font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
		});
		title.anchor.set(0.5, 0.5);
		title.x = 2048 / 2;
		title.y = 700;
		homeScreen.addChild(title);
		// Fun subtitle
		var subtitle = new Text2("Pop the right letter bubbles!", {
			size: 90,
			fill: 0x9013FE,
			font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
		});
		subtitle.anchor.set(0.5, 0.5);
		subtitle.x = 2048 / 2;
		subtitle.y = 900;
		homeScreen.addChild(subtitle);
		// (Sample letters removed for a cleaner home screen)
		// Game mode buttons
		var modeBtnY = 1450;
		var modeBtnSpacing = 220;
		var modeBtnScale = 1.15;
		// Endless Mode Button
		var endlessBtn = LK.getAsset('bubbleBlue', {
			anchorX: 0.5,
			anchorY: 0.5,
			x: 2048 / 2,
			y: modeBtnY,
			scaleX: modeBtnScale,
			scaleY: modeBtnScale
		});
		homeScreen.addChild(endlessBtn);
		var endlessText = new Text2("Endless Mode", {
			size: 90,
			fill: "#fff",
			font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
		});
		endlessText.anchor.set(0.5, 0.5);
		endlessText.x = endlessBtn.x;
		endlessText.y = endlessBtn.y;
		homeScreen.addChild(endlessText);
		// Timed Mode Button
		var timedBtn = LK.getAsset('bubbleOrange', {
			anchorX: 0.5,
			anchorY: 0.5,
			x: 2048 / 2,
			y: modeBtnY + modeBtnSpacing,
			scaleX: modeBtnScale,
			scaleY: modeBtnScale
		});
		homeScreen.addChild(timedBtn);
		var timedText = new Text2("Timed Mode", {
			size: 90,
			fill: "#fff",
			font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
		});
		timedText.anchor.set(0.5, 0.5);
		timedText.x = timedBtn.x;
		timedText.y = timedBtn.y;
		homeScreen.addChild(timedText);
		// Hard Mode Button
		var hardBtn = LK.getAsset('bubbleRed', {
			anchorX: 0.5,
			anchorY: 0.5,
			x: 2048 / 2,
			y: modeBtnY + 2 * modeBtnSpacing,
			scaleX: modeBtnScale,
			scaleY: modeBtnScale
		});
		homeScreen.addChild(hardBtn);
		var hardText = new Text2("Hard Mode", {
			size: 90,
			fill: "#fff",
			font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
		});
		hardText.anchor.set(0.5, 0.5);
		hardText.x = hardBtn.x;
		hardText.y = hardBtn.y;
		homeScreen.addChild(hardText);
		// Add homeScreen to game
		game.addChild(homeScreen);
		// Button interactions
		endlessBtn.down = function () {
			game.removeChild(homeScreen);
			selectedGameMode = "endless";
			actuallyStartGame();
		};
		endlessText.down = endlessBtn.down;
		timedBtn.down = function () {
			game.removeChild(homeScreen);
			selectedGameMode = "timed";
			actuallyStartGame();
		};
		timedText.down = timedBtn.down;
		hardBtn.down = function () {
			game.removeChild(homeScreen);
			selectedGameMode = "hard";
			actuallyStartGame();
		};
		hardText.down = hardBtn.down;
		// Don't start the game yet!
		return;
	}
	actuallyStartGame();
	function actuallyStartGame() {
		currentLetterIdx = 0;
		score = 0;
		scoreText.setText(score);
		feedbackText.alpha = 0;
		correctInARow = 0;
		lettersPerRound = 4;
		// Set game mode defaults
		if (typeof selectedGameMode === "undefined") {
			selectedGameMode = "endless";
		}
		// Endless Mode: no timer, endless play, normal bubbles
		// Timed Mode: timer, increasing difficulty, normal/zigzag bubbles
		// Hard Mode: no timer, all bubbles zigzag/faded, increasing count
		if (selectedGameMode === "endless") {
			endlessMode = true;
			timerActive = false;
			timerValue = 0;
			timerText.setText('');
			if (timerInterval) {
				LK.clearInterval(timerInterval);
				timerInterval = null;
			}
		} else if (selectedGameMode === "timed") {
			endlessMode = false;
			timerActive = true;
			timerValue = TIMER_START;
			timerText.setText('Time: ' + timerValue);
			if (timerInterval) {
				LK.clearInterval(timerInterval);
				timerInterval = null;
			}
			timerInterval = LK.setInterval(function () {
				if (!timerActive) return;
				timerValue--;
				timerText.setText('Time: ' + timerValue);
				if (timerValue <= 0) {
					timerValue = 0;
					timerText.setText('Time: 0');
					endGameTimeout();
				}
			}, 1000);
		} else if (selectedGameMode === "hard") {
			endlessMode = true;
			timerActive = false;
			timerValue = 0;
			timerText.setText('');
			if (timerInterval) {
				LK.clearInterval(timerInterval);
				timerInterval = null;
			}
		}
		// Reload high score from storage
		highScore = storage.letterpop_highscore || 0;
		highScoreText.setText('High Score: ' + highScore);
		startRound();
	}
}
// Start on load
startGame();
// Animate zigzag bubbles (if any) each frame
game.update = function () {
	for (var i = 0; i < bubbles.length; i++) {
		if (typeof bubbles[i].update === "function") {
			bubbles[i].update();
		}
	}
};
// Touchscreen: No drag/move needed, only tap (down) on bubbles
// Make sure no elements are in top-left 100x100 (all UI is top/center/right);;
// --- Add navigation button to return to main menu ---
// We'll use a simple colored bubble as the button, with a "home" icon/text overlay
var navBtn = LK.getAsset('bubbleGreen', {
	anchorX: 1,
	anchorY: 0,
	x: 2048 - 40,
	// 40px from right edge
	y: 40,
	// 40px from top edge
	scaleX: 0.7,
	scaleY: 0.7
});
var navBtnText = new Text2("⌂", {
	size: 110,
	fill: "#fff",
	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
});
navBtnText.anchor.set(0.5, 0.5);
navBtnText.x = navBtn.width / 2;
navBtnText.y = navBtn.height / 2;
navBtn.addChild(navBtnText);
// Add to LK.gui.topRight so it stays in the top-right corner
LK.gui.topRight.addChild(navBtn);
// Show/hide navBtn depending on whether we're in gameplay or home screen
function showNavBtn(show) {
	navBtn.visible = !!show;
}
// Always hide navBtn on home screen, show on gameplay
showNavBtn(false);
// Patch actuallyStartGame to show navBtn
var _oldActuallyStartGame = actuallyStartGame;
actuallyStartGame = function actuallyStartGame() {
	showNavBtn(true);
	_oldActuallyStartGame();
};
// Patch startGame to hide navBtn on home screen
var _oldStartGame = startGame;
startGame = function startGame() {
	showNavBtn(false);
	_oldStartGame();
};
// Also hide navBtn on game over or win
var _oldEndGameTimeout = endGameTimeout;
endGameTimeout = function endGameTimeout() {
	showNavBtn(false);
	_oldEndGameTimeout();
};
var _oldShowCelebration = showCelebration;
showCelebration = function showCelebration() {
	showNavBtn(false);
	_oldShowCelebration();
};
// When navBtn is tapped, go back to home screen (reset game)
navBtn.down = function () {
	// Hide navBtn immediately
	showNavBtn(false);
	// Remove all bubbles and reset state
	for (var i = 0; i < bubbles.length; i++) {
		bubbles[i].destroy();
	}
	bubbles = [];
	// Remove any feedback/prompt
	promptText.setText('');
	feedbackText.alpha = 0;
	// Stop timer if running
	timerActive = false;
	if (timerInterval) {
		LK.clearInterval(timerInterval);
		timerInterval = null;
	}
	// Show home screen again
	startGame.hasRun = undefined; // allow home screen to show again
	startGame();
};

===================================================================
--- original.js
+++ change.js
@@ -841,5 +841,79 @@
 		}
 	}
 };
 // Touchscreen: No drag/move needed, only tap (down) on bubbles
-// Make sure no elements are in top-left 100x100 (all UI is top/center/right);
\ No newline at end of file
+// Make sure no elements are in top-left 100x100 (all UI is top/center/right);;
+// --- Add navigation button to return to main menu ---
+// We'll use a simple colored bubble as the button, with a "home" icon/text overlay
+var navBtn = LK.getAsset('bubbleGreen', {
+	anchorX: 1,
+	anchorY: 0,
+	x: 2048 - 40,
+	// 40px from right edge
+	y: 40,
+	// 40px from top edge
+	scaleX: 0.7,
+	scaleY: 0.7
+});
+var navBtnText = new Text2("⌂", {
+	size: 110,
+	fill: "#fff",
+	font: "GillSans-Bold,Impact,'Arial Black',Tahoma"
+});
+navBtnText.anchor.set(0.5, 0.5);
+navBtnText.x = navBtn.width / 2;
+navBtnText.y = navBtn.height / 2;
+navBtn.addChild(navBtnText);
+// Add to LK.gui.topRight so it stays in the top-right corner
+LK.gui.topRight.addChild(navBtn);
+// Show/hide navBtn depending on whether we're in gameplay or home screen
+function showNavBtn(show) {
+	navBtn.visible = !!show;
+}
+// Always hide navBtn on home screen, show on gameplay
+showNavBtn(false);
+// Patch actuallyStartGame to show navBtn
+var _oldActuallyStartGame = actuallyStartGame;
+actuallyStartGame = function actuallyStartGame() {
+	showNavBtn(true);
+	_oldActuallyStartGame();
+};
+// Patch startGame to hide navBtn on home screen
+var _oldStartGame = startGame;
+startGame = function startGame() {
+	showNavBtn(false);
+	_oldStartGame();
+};
+// Also hide navBtn on game over or win
+var _oldEndGameTimeout = endGameTimeout;
+endGameTimeout = function endGameTimeout() {
+	showNavBtn(false);
+	_oldEndGameTimeout();
+};
+var _oldShowCelebration = showCelebration;
+showCelebration = function showCelebration() {
+	showNavBtn(false);
+	_oldShowCelebration();
+};
+// When navBtn is tapped, go back to home screen (reset game)
+navBtn.down = function () {
+	// Hide navBtn immediately
+	showNavBtn(false);
+	// Remove all bubbles and reset state
+	for (var i = 0; i < bubbles.length; i++) {
+		bubbles[i].destroy();
+	}
+	bubbles = [];
+	// Remove any feedback/prompt
+	promptText.setText('');
+	feedbackText.alpha = 0;
+	// Stop timer if running
+	timerActive = false;
+	if (timerInterval) {
+		LK.clearInterval(timerInterval);
+		timerInterval = null;
+	}
+	// Show home screen again
+	startGame.hasRun = undefined; // allow home screen to show again
+	startGame();
+};
\ No newline at end of file