//code inside $(function(){} will run after the DOM is loaded and ready
var KEY = {
	UP: 38,
	DOWN: 40,
	W: 87,
	S: 83
}

var pingpong = {
	scoreA : 0, //score for player A
	scoreB : 0  //score for player B
}
pingpong.pressedKeys = [];
pingpong.ball = {
	speed: 5,
	x: 150,
	y: 100,
	directionX: 1,
	directionY: 1
}

var WINNER = 3;

$(function(){
	//set interval to call gameloop every 30 milliseconds
	pingpong.timer = setInterval(gameloop,30);

	//mark down what key is down and up into an array called "pressedKeys"
	$(document).keydown(function(e){
	pingpong.pressedKeys[e.which] = true;
	});
	$(document).keyup(function(e){
	pingpong.pressedKeys[e.which] = false;
	});
});

function gameloop() {
	if (pingpong.scoreA < WINNER && pingpong.scoreB < WINNER) {
		moveBall();
		movePaddles();
	}
	else {
		endGame();
	}
}

function moveBall() {
	//reference useful variables
	var playgroundHeight = parseInt($("#playground").height());
	var playgroundWidth = parseInt($("#playground").width());
	var ball = pingpong.ball;

	//check playground boundary
	//check bottom edge
	if (ball.y + ball.speed*ball.directionY > playgroundHeight) {
	ball.directionY = -1;
	}

	//check top edge
	if (ball.y + ball.speed*ball.directionY < 0) {
	ball.directionY = 1;
	}

	//check right edge
	if (ball.x + ball.speed*ball.directionX > playgroundWidth) {
	ball.directionX = -1;
	}

	//check left edge
	if (ball.x + ball.speed*ball.directionX < 0) {
	ball.directionX = 1;
	}

	ball.x += ball.speed*ball.directionX;
	ball.y += ball.speed*ball.directionY;

	//check moving paddle here
	//check left paddle
	var paddleAX = parseInt($("#paddleA").css("left"))+parseInt($("#paddleA").css("width"));
	var paddleAYBottom = parseInt($("#paddleA").css("top"))+parseInt($("#paddleA").css("height"));
	var paddleAYTop = parseInt($("#paddleA").css("top"));

	if (ball.x + ball.speed*ball.directionX < paddleAX) {
		if ((ball.y + ball.speed*ball.directionY <= paddleAYBottom) && (ball.y + ball.speed*ball.directionY >= paddleAYTop))
		{
			ball.directionX = 1;
		}
	}

	//check right paddle
	var paddleBX = parseInt($("#paddleB").css("left"))-parseInt($("#ball").css("width"));
	var paddleBYBottom = parseInt($("#paddleB").css("top"))+parseInt($("#paddleB").css("height"));
	var paddleBYTop = parseInt($("#paddleB").css("top"));

	if (ball.x + ball.speed*ball.directionX >= paddleBX) {
		if ((ball.y + ball.speed*ball.directionY <= paddleBYBottom) && (ball.y + ball.speed*ball.directionY >= paddleBYTop))
		{
			ball.directionX = -1;
		}
	}

	//check right edge
	if (ball.x + ball.speed*ball.directionX > playgroundWidth) {
		//player B lost; reset ball.
		pingpong.scoreA++;
		$("#scoreA").html(pingpong.scoreA);
		ball.x = 250;
		ball.y = 100;
		$("#ball").css({
			"left" : ball.x,
			"top" : ball.y
		});
		ball.directionX = -1;
	}

	//check left edge
	if (ball.x + ball.speed*ball.directionX < 0) {
		//player A lost; reset ball.
		pingpong.scoreB++;
		$("#scoreB").html(pingpong.scoreB);
		ball.x = 150;
		ball.y = 100;
		$("#ball").css({
			"left" : ball.x,
			"top" : ball.y
		});
		ball.directionX = 1;
	}

	//actually move ball with speed and direction
	$("#ball").css({
		"left" : ball.x,
		"top" : ball.y
	});
}
function movePaddles(){
	//use custom timer to continuously check if a key is pressed
	var playgroundHeight = parseInt($("#playground").height()); //added for edge check

	if (pingpong.pressedKeys[KEY.UP]) { //arrow-up
		//move paddle B up 5 pixels
		var top = parseInt($("#paddleB").css("top"));
		if (top > 0) { //edge check
			$("#paddleB").css("top",top-5);
		}
	}

	if (pingpong.pressedKeys[KEY.DOWN]) { //arrow-down
		//move paddle B down 5 pixels
		var top = parseInt($("#paddleB").css("top"));
		if (top < (playgroundHeight-70)) { //edge check
			$("#paddleB").css("top",top+5);
		}
	}

	if (pingpong.pressedKeys[KEY.W]) { //w
		//move paddle A up 5 pixels
		var top = parseInt($("#paddleA").css("top"));
		if (top > 0) { //edge check
			$("#paddleA").css("top",top-5);
		}
	}

	if (pingpong.pressedKeys[KEY.S]) { //s
		//move paddle A down 5 pixels
		var top = parseInt($("#paddleA").css("top"));
		if (top < (playgroundHeight-70)) { //edge check
			$("#paddleA").css("top",top+5);
		}
	}
}

function endGame() {
	if (pingpong.scoreA >= WINNER) {
		$("#winner").html("Player A has won the game!")
	}

	else {
		$("#winner").html("Player B has won the game!")
	}
	clearInterval(pingpong.timer);
}