game.js

window.onload = function() {	
	var game = new Phaser.Game(500, 900, Phaser.CANVAS, "", {
		preload: onPreload,
		create: onCreate
	});
	var sumsArray = []; 
	var questionText;
	var randomSum;
	var timeTween;
	var numberTimer;
	var buttonMask;
	var score=0;
	var scoreText;
     var isGameOver = false;
     var topScore;
     var numbersArray = [-3,-2,-1,1,2,3];
	function buildThrees(initialNummber,currentIndex,limit,currentString){
		for(var i=0;i<numbersArray.length;i++){
			var sum = initialNummber+numbersArray[i];
			var outputString = currentString+(numbersArray[i]<0?"":"+")+numbersArray[i];
			if(sum>0 && sum<4 && currentIndex==limit){
				sumsArray[limit][sum-1].push(outputString);
			}
			if(currentIndex<limit){
				buildThrees(sum,currentIndex+1,limit,outputString);	
			}
		}	
	}
	function onPreload() {
		game.load.image("timebar", "timebar.png");
		game.load.image("buttonmask", "buttonmask.png");
		game.load.spritesheet("buttons", "buttons.png",400,50);
	}
	function onCreate() {
		topScore = localStorage.getItem("topScore")==null?0:localStorage.getItem("topScore");
		game.stage.backgroundColor = "#cccccc";
		game.stage.disableVisibilityChange = true;
		for(var i=1;i<5;i++){
			sumsArray[i]=[[],[],[]];
			for(var j=1;j<=3;j++){
				buildThrees(j,1,i,j);
			}
		}
		questionText = game.add.text(250,160,"-",{
			font:"bold 72px Arial"
		});
		questionText.anchor.set(0.5);
		scoreText = game.add.text(10,10,"-",{
			font:"bold 24px Arial"
		});
		for(var i=0;i<3;i++){
			var numberButton = game.add.button(50,250+i*75,"buttons",checkAnswer,this).frame=i; 
		}
		numberTimer =  game.add.sprite(50,250,"timebar");
		nextNumber();		
	}
	function gameOver(gameOverString){
		game.stage.backgroundColor = "#ff0000";
		questionText.text = questionText.text+" = "+gameOverString;
          isGameOver = true;
		localStorage.setItem("topScore",Math.max(score,topScore));
	}
	function checkAnswer(button){
		if(!isGameOver){
               if(button.frame==randomSum){
     			score+=Math.floor((buttonMask.x+350)/4);
				nextNumber();     			
     		}
     		else{
     			if(score>0) {
     				timeTween.stop();
     			}
     			gameOver(button.frame+1);
     		}
          }
	}
	function nextNumber(){
		scoreText.text = "Score: "+score.toString()+"\nBest Score: "+topScore.toString();
		if(buttonMask){
			buttonMask.destroy();
               game.tweens.removeAll();
		}  
		buttonMask = game.add.graphics(50, 250);
		buttonMask.beginFill(0xffffff);
		buttonMask.drawRect(0, 0, 400, 200);
		buttonMask.endFill();
		numberTimer.mask = buttonMask;
		if(score>0){
			timeTween=game.add.tween(buttonMask);
			timeTween.to({
				x: -350
			}, 3000, "Linear",true);
			timeTween.onComplete.addOnce(function(){
	               gameOver("?");
	          }, this);
          }
		randomSum = game.rnd.between(0,2);  
		questionText.text = sumsArray[Math.min(Math.round((score-100)/400)+1,4)][randomSum][game.rnd.between(0,sumsArray[Math.min(Math.round((score-100)/400)+1,4)][randomSum].length-1)];
	}	
}