var TIMEOUT=3.5; // seconds before change left image
var INTERVAL=2.5; // interval behind showing images

var CURRENT_L=0;
var CURRENT_C=0;
var CURRENT_R=0;
var WAS_L=null;
var WAS_C=null;
var WAS_R=null;
var left_t=null;
var center_t=null;
var right_t=null;
var left_i=null;
var center_i=null;
var right_i=null;
var PATH='images/';
var NUM_L=0;
var NUM_C=0;
var NUM_R=0;

window.onload=loadSlider;

function loadSlider () {
	window.LEFT_IMAGE=document.getElementById('left_image');
	window.CENTER_IMAGE=document.getElementById('center_image');
	window.RIGHT_IMAGE=document.getElementById('right_image');
	window.imagesL=Array('l2.jpg', 'l3.jpg', 'l4.jpg');
	window.imagesC=Array('c2.jpg', 'c3.jpg', 'c4.jpg');
	window.imagesR=Array('r2.jpg', 'r3.jpg', 'r4.jpg');
	loadImages(imagesL);
	loadImages(imagesC);
	loadImages(imagesR);
	WAS_L=rand(imagesL.length);
	WAS_C=rand(imagesC.length);
	WAS_R=rand(imagesR.length);
	//LEFT_IMAGE.src=PATH+imagesL[WAS_L];
	//RIGHT_IMAGE.src=PATH+imagesR[WAS_R];
	left_i=setTimeout("setInterval('changeImages(\"l\")', TIMEOUT*2000);", 0);
	center_i=setTimeout("setInterval('changeImages(\"c\")', TIMEOUT*2000);", INTERVAL*1000);
	right_i=setTimeout("setInterval('changeImages(\"r\")', TIMEOUT*2000);", INTERVAL*2000);
	return;
}

function changeImages(type) {
	if (type=='l') {
		if (CURRENT_L>=imagesL.length) {
			CURRENT_L=0;
			WAS_L=-1;
		}

		if (CURRENT_L==WAS_L) {
			NUM_L=CURRENT_L+1;
			CURRENT_L+=2;
		}
		else {
			NUM_L=CURRENT_L;
			CURRENT_L++;
		}

		clearTimeout(left_t);
		new Effect.Opacity('test_l', {duration: 1.9, from: 0.0, to: 1.0});
		left_t=setTimeout("LEFT_IMAGE.src=PATH+imagesL[NUM_L];", 100);
	}
	else if (type=='r') {
		if (CURRENT_R>=imagesR.length) {
			CURRENT_R=0;
			WAS_R=-1;
		}

		if (CURRENT_R==WAS_R) {
			NUM_R=CURRENT_R+1;
			CURRENT_R+=2;
		}
		else {
			NUM_R=CURRENT_R;
			CURRENT_R++;
		}

		clearTimeout(right_t);
		new Effect.Opacity('test_r', {duration: 1.9, from: 0.0, to: 1.0});
		right_t=setTimeout("RIGHT_IMAGE.src=PATH+imagesR[NUM_R];", 100);
	}
	else if (type=='c') {
		if (CURRENT_C>=imagesC.length) {
			CURRENT_C=0;
			WAS_C=-1;
		}

		if (CURRENT_C==WAS_C) {
			NUM_C=CURRENT_C+1;
			CURRENT_C+=2;
		}
		else {
			NUM_C=CURRENT_C;
			CURRENT_C++;
		}

		clearTimeout(center_t);
		new Effect.Opacity('test_c', {duration: 1.9, from: 0.0, to: 1.0});
		right_t=setTimeout("CENTER_IMAGE.src=PATH+imagesC[NUM_C];", 100);
	}
	return;
}

function loadImages (imagesArray) {
	for (i in imagesArray) {
		var current= new Image();
		current.src=PATH+imagesArray[i];
	}
}

function rand (n) {
	return ((Math.floor(Math.random()*n+1))-1);
}