//(C) Ben Huntley, May 2007

/* 
 * the following constants are defined on each page
 *
 * var MENU									// horizontal nav menu to highlight 
 * var GALLERY								// div element containing display image 
 * var IMG_DIR								// image directory 
 * var MAX_PIC								// max number of images in the current gallery 
 */
var MENU_COUNT = 3;
function show(id) {
    var d = document.getElementById(id);
	for (var i = 1; i<=MENU_COUNT; i++) {
		if (document.getElementById('smenu'+i)) {document.getElementById('smenu'+i).style.display='none';}
	}
   	if (d) {d.style.display='block';}
}
function showHighlight(id) {
    var d = document.getElementById(id);
	for (var i = 1; i<=MENU_COUNT; i++) {
		if (document.getElementById('smenu'+i)) {document.getElementById('smenu'+i).style.display='none';}
	}
    if (d) {d.style.display='block';}
	darkenText(MENU);
}
var NEXT = true;
var picID = 'p01'; 
function updatePic(p){
	var lastButton = document.getElementById(picID);
	var d = document.getElementById(p);
	if(d){
		lastButton.style.backgroundColor='#FFF';
		d.style.backgroundColor='#eee';
		var img = document.getElementById(GALLERY);		
		p = p.substring(1);		
		img.style.backgroundImage='url(' + IMG_DIR + p + '.jpg)';
		picID = 'p' + p;
	}
}
function nextPic(direction){
	var i = picID.substring(1);
	i = parseCustomInt(i);
	if(direction == NEXT){
		if(i == MAX_PIC) i = 1;
		else i++;
	}
	else{
		if(i == 1) i = MAX_PIC;
		else i--;
	}
	var zeros = 0
	if (i < 10) zeros = 1;
	i = parseCustomString(i, zeros);
	i = 'p' + i;
	updatePic(i);
}
function parseCustomInt(i){
	if(i.substring(0,1) == '0') return parseCustomInt(i.substring(1));
	else return parseInt(i);
}
function parseCustomString(s, z){
	if(z <= 0) return s.toString();
	else return '0' + parseCustomString(s, z-1);
}
function darkenText(e){
	var p = document.getElementById(e).getElementsByTagName('a')[0];
	if(p){	
		p.style.color='#000';
		p.style.textDecoration='underline';
	}
}
function main(){
	show();
	darkenText(MENU);
	updatePic('p01');
}