// slides.js - new homepage slides feature
// Author: Jing Chen
// Date: 2009/07/01
// Requirements: Written to work with client side Javascript 1.3 or better.

// variables   
var slideShowTimer = null;
var textSlideTimer = null;
var leftInitial = 150;
var left = leftInitial;
var isSlideShow = true;

function show(n, startSlideShow) 
{
    // stop slide show if user selects any slide by hand
    if (startSlideShow == false)
        isSlideShow = false;    
    if (isSlideShow == false && startSlideShow == true)
        return;
    
    // clear any outstanding timers
    if (textSlideTimer != null)
        clearTimeout(textSlideTimer);
    if (textSlideTimer != null)
        clearInterval(textSlideTimer);    
    left = leftInitial;
        
    // show selected icon
    for (var i=1; i<=4; i++){
        var icon = document.getElementById("slide-icon-" + i);
        if (i == n)
            icon.src = "/interface/gfx/2008/home-icon-slide-" + i + "-sel.png";
        else
            icon.src = "/interface/gfx/2008/home-icon-slide-" + i + ".png";
    }
  
    // show selected slide
    var slide = document.getElementById("slide");
    slide.style.backgroundImage = "url(/interface/gfx/slides/current/slide-" + prefix + n + ".png)";
   
    // show selected text    
    showText(n);
    
    // schedule next slide automatically
    if (isSlideShow == true && n < 4)
        slideShowTimer = setTimeout("show(" + (n+1) + "," + isSlideShow + ")", 5000);
}

function showText(n)
{
    // show selected text
    var title = document.getElementById("slide-title");
    var caption = document.getElementById("slide-caption");    
    title.innerHTML = text[(n-1)*2];    
    caption.innerHTML = text[(n-1)*2+1];   
    
    // scroll selected text    
    textSlideTimer = self.setInterval("slideInText()", 1);
}

var increment = 2;
var slideText = null;
function slideInText() {
    // reset timer if in place
	if (left <= 0) 
	{
	    left = leftInitial;
		clearInterval(textSlideTimer);
		return;
    }
		
    // slide text to the left	
	if (slideText == null)
	    slideText = document.getElementById("slide-text");
	left -= increment;	
	slideText.style.marginLeft = left + "px";
	slideText.style.marginRight = "-" + left + "px";	
}