"use strict";
var $ = function(id) { return document.getElementById(id); };

var getRandomNumber = function(max) {
var random;
if (!isNaN(max)) {
    random = Math.random(); //value >= 0.0 and < 1.0
    random = Math.floor(random * max); //value is an integer between 0 and max - 1
    random = random + 1; //value is an integer between 1 and max
}
return random;
};

var playGame = function() {
var odd = 0;
var even = 0;
var player, computer, total;
resetFields(); // clear any previous entries

while (odd < 50 && even < 50) {
    //get computers fingers
    computer = getRandomNumber(5);
    // get player's fingers
    player = parseInt(prompt("Enter a number between 1 and 5, or 999 to quit", 999));
    
    if (!isNaN(player) && player <= 5) {
        // show current round
        $("player").value = player;
        $("computer").value = computer;
        
        // update totals
        total = player + computer;
        if (total % 2 === 0) {
            even = even + total;
            $("even").value = even;
        } else {
            odd = odd + total;
            $("odd").value = odd;
        }
    }
    //if loop for player quitting
    if (player === 999) {
    resetFields();
    break;
    }
}
//after loop ends, determine winner
if (odd >= 50) { $("message").firstChild.nodeValue = "You WIN!"; }
else if (even >= 50) { $("message").firstChild.nodeValue = "You lose :("; }
else { $("message").firstChild.nodeValue = "You quit"; }

// set focus on button so you can play again
$("play").focus();
};

var resetFields = function() {
$("player").value = "0";
$("computer").value = "0";
$("odd").value = "0";
$("even").value = "0";
$("message").firstChild.nodeValue = "";
};

window.onload = function() {
$("play").onclick = playGame;
$("play").focus();
};