// JavaScript Document
// script for changing the main image
var $tstep = 10;
var $wstep = 10;	
var $mainleft = document.getElementById('mainleft');
var $maxw = 0;
var $i = 0;
var $pic = 0;
var $new_img = "";
var $trans = 0; // 0 - simple switch, 1 - curtains close and open

function show( $transition, $img, $main_img_w )
 {
 $maxw = $main_img_w;
	$new_img = $img;
	$trans = $transition;
	$i = 0;
	$pic = 0;
	//alert( "TRANS:" + $trans + "; NEW_IMG:" + $new_img + "; MAXW:" + $maxw + "; I:" + $i + "; " );
	if( $trans==0 )
	 { document.getElementById('mainpic').src = $new_img; }
	if( $trans==1 )
  { showit(); }
	}

function showit()
 {
	$i = $i + $wstep;
	if( $i < $maxw /2 )
	 {
		$w = $i;
		// left curtain
		document.getElementById('mainleft').style.width = $w + "px";
		// right curtain
		document.getElementById('mainright').style.width = $w + "px";
		document.getElementById('mainright').style.left  = $maxw - $w + "px";
		// both
  setTimeout( "showit()", $tstep );
		}
 else if( $pic == 0 )
	 {
		document.getElementById('mainpic').src = $new_img;
		$pic = 1;
  setTimeout( "showit()", 10*$tstep );		
		}
 else if( $i < $maxw )
	 {
 	$i = $i + $wstep;
		$w = $maxw - $i;
		// left curtain
		document.getElementById('mainleft').style.width = $w + "px";
		// right curtain
		document.getElementById('mainright').style.width = $w + "px";
		document.getElementById('mainright').style.left  = $maxw - $w + "px";
		// both
  setTimeout( "showit()", $tstep );		
		}
 else
	 {
		document.getElementById('mainleft').style.width = "0px";	
		document.getElementById('mainright').style.width = "0px";	
		}
 }

var $run_show = 0;
var $imgDir = "";
var $picIndex = 0;
var $slide_delay = 0;

function start_slideshow( $transition, $main_img_w, $image_dir, $slidedelay )
 {
 $trans = $transition;
 $maxw = $main_img_w;
	$imgDir = $image_dir;
	$slide_delay = $slidedelay;
	$run_show = 1;
	$img = document.getElementById('mainpic').src;
	var $pattern = /(.*)\/([^\/]*$)/;
	var $result = $img.match( $pattern );
	var $picname = $result[2];

 // hide start link and show stop link
	document.getElementById('start_slideshow').style.visibility = "hidden";
	document.getElementById('stop_slideshow').style.visibility = "visible";
	
	// find the index of the current picture
	$picIndex = 0;
	for( $n=0; $n<$picArray.length; $n++ )
	 {
		if( $picname == $picArray[$n] )
		 {
			$picIndex = $n;
			}
		}
	//alert( "PIC_INDEX = " + $picIndex );	

 // show images
	setTimeout( "show_next_pic()", $slide_delay );
}

function show_next_pic()
 {
	if( $run_show )
	 {
		if( $picIndex<$picArray.length )
		 { $picIndex = $picIndex + 1; }
		else
		 { $picIndex = 0; }
	 $img = $imgDir + "/" + $picArray[$picIndex];
		//alert( "SLIDESHOW: " + $img );
 	show( $trans, $img, $maxw );
	 setTimeout( "show_next_pic()", $slide_delay );
  }
	}
	
function stop_slideshow()
 { 
	$run_show = 0;	

 // show start link and hide stop link
	document.getElementById('start_slideshow').style.visibility = "visible";
	document.getElementById('stop_slideshow').style.visibility = "hidden";
	}