var aFilmstrip = new Array();
aFilmstrip[0]  = 'anncar.jpg';
aFilmstrip[1]  = 'atsea.jpg';
aFilmstrip[2]  = 'fatherson.jpg';
aFilmstrip[3]  = 'flower.jpg';
aFilmstrip[4]  = 'laff.jpg';
aFilmstrip[5]  = 'oceangreen.jpg';
aFilmstrip[6]  = 'picnic.jpg';
aFilmstrip[7]  = 'popsicle.jpg';
aFilmstrip[8]  = 'robertbike1.jpg';
aFilmstrip[9]  = 'robertbike2.jpg';
aFilmstrip[10] = 'robertblur.jpg';
aFilmstrip[11] = 'robertbroken.jpg';
aFilmstrip[12] = 'roberthair.jpg';
aFilmstrip[13] = 'running.jpg';

function getRandomNumber(ceiling) {
	return Math.floor(Math.random() * (ceiling+1));
}

function shuffleFilmstrip() {
	if (!document.getElementById) return;
	
	var aImages = document.getElementsByTagName('img');
	var aStrips = new Array();
	var aUsed = new Array();
	var aNewFilmstrip = new Array();
	// init aUsed
	for (var i=0; i<aFilmstrip.length; i++) aUsed[i] = 0;
	// init aStrips
	var currStrip = 0;
	for (var i=0; i<aImages.length; i++) {
		if (aImages[i].className == 'filmstrip') {
			aStrips[currStrip++] = aImages[i];
		}
	}
	var counter = 0;
	for (var i=0; i<aStrips.length; i++) {
		var useStrip = -1;
		while (useStrip < 0) {
			useStrip = getRandomNumber(aFilmstrip.length-1);
			if (aUsed[useStrip] > 0) { // used that index already
				useStrip = -1;
			} else {
				aUsed[useStrip] = 1;
				aNewFilmstrip[counter++] = useStrip;
			}
		}
	}
	// aNewFilmstrip is in order of randoms, flip coin and set regular or -wash
	for (var i=0; i<aNewFilmstrip.length; i++) {
		var nonzero = getRandomNumber(1); // coin flip
		var newNdx = aNewFilmstrip[i];
		if (nonzero) {
			// use -wash
			var src = aFilmstrip[newNdx];
			var ftype = src.substring(src.lastIndexOf('.'), src.length);
			var swapsrc = src.replace(ftype, '-wash'+ftype);
			aStrips[i].setAttribute('src','images/filmstrip/'+swapsrc);
		} else {
			aStrips[i].setAttribute('src','images/filmstrip/'+aFilmstrip[newNdx]);
		}
	}
}

addLoadEvent(shuffleFilmstrip);