/*
This script takes the array passed from getImages.php,
shuffles the array, preloads the images, then displays
the images in their shuffled sequence. Loops ferever.
*/

//Define variables
var img = []; // preloading array
var len = galleryarray.length; // length
var timeBasis = 4; // in seconds
var imgNum = 0;
var play = true;

//Shuffle the array
shuffle(galleryarray);

// preload images
for(i=0; i<galleryarray.length; i++) {
	img[i] = new Image();
	img[i].src = ('http://academic.reed.edu/biology/professors/rkaplan/slideshow-fixed/images/' + galleryarray[i]);
}

// FUNCTIONS...

function showImg() {
	document.write('<img src="'+img[0].src+'" name="slideshow" class="slideshow">');
	setInterval("updateImg()", timeBasis*1000);
}

function updateImg() {
	if (play) { // check if play button is on
	  imgNum = imgNum + 1;
	  if (imgNum > (len-1)) { //so it loops
		  imgNum = 0;
	  }
	}
	document.images['slideshow'].src = img[imgNum].src;
}

function shuffle(o) {
	for(var j, x, i = o.length; i; j = parseInt(Math.random() * i), x = o[--i], o[i] = o[j], o[j] = x);
	return o;
}

function playButton() {
	var e = document.getElementById("b");
	var currentLabel = e.value;

	if (currentLabel == "Pause") {
	  document.getElementById("b").value = "Play";
	  play = false;
      } else {
	  document.getElementById("b").value = "Pause";
	  play = true;
	}
}