/* Smooth scrolling
   Changes links that link to other parts of this page to scroll
   smoothly to those links rather than jump to them directly, which
   can be a little disorienting.
   
   sil, http://www.kryogenix.org/
   
   v1.0 2003-11-11
   v1.1 2005-06-16 wrap it up in an object
*/

var ss = {
  fixAllLinks: function() {
    // Get a list of all links in the page
    var allLinks = document.getElementsByTagName('a');
    // Walk through the list
    for (var i=0;i<allLinks.length;i++) {
      var lnk = allLinks[i];
      if ((lnk.href && lnk.href.indexOf('#') != -1) && 
          ( (lnk.pathname == location.pathname) ||
	    ('/'+lnk.pathname == location.pathname) ) && 
          (lnk.search == location.search)) {
        // If the link is internal to the page (begins in #)
        // then attach the smoothScroll function as an onclick
        // event handler
        ss.addEvent(lnk,'click',ss.smoothScroll);
      }
    }
  },

  smoothScroll: function(e) {
	  
	  
	 // --- added by Joel Brehm for UNL Research News ------------------------------------------------------------------------------------------------------------------- 
    
	yScroll = getScrollHeight();
	notesLink = findDestLink(document.getElementById("newsnotesPositionHolder"));
	resourcesLink = findDestLink(document.getElementById("resoucresPositionHolder"));
	aboutLink = findDestLink(document.getElementById("aboutPositionHolder"));
	
	 // --------end added code----------------------------------------------------------------------------------------------------------------------------------------------------------- 
	  
	  
	  
    // This is an event handler; get the clicked on element,
    // in a cross-browser fashion
    if (window.event) {
      target = window.event.srcElement;
    } else if (e) {
      target = e.target;
    } else return;

    // Make sure that the target is an element, not a text node
    // within an element
    if (target.nodeName.toLowerCase() != 'a') {
      target = target.parentNode;
    }
  
    // Paranoia; check this is an A tag
    if (target.nodeName.toLowerCase() != 'a') return;
  
    // Find the <a name> tag corresponding to this href
    // First strip off the hash (first character)
    anchor = target.hash.substr(1);
    // Now loop all A tags until we find one with that name
    var allLinks = document.getElementsByTagName('a');
    var destinationLink = null;
    for (var i=0;i<allLinks.length;i++) {
      var lnk = allLinks[i];
      if (lnk.name && (lnk.name == anchor)) {
        destinationLink = lnk;
        break;
      }
    }
    if (!destinationLink) destinationLink = document.getElementById(anchor);

    // If we didn't find a destination, give up and let the browser do
    // its thing
    if (!destinationLink) return true;
  
    // Find the destination's position
    var destx = destinationLink.offsetLeft; 
    var desty = destinationLink.offsetTop;
    var thisNode = destinationLink;
    while (thisNode.offsetParent && 
          (thisNode.offsetParent != document.body)) {
      thisNode = thisNode.offsetParent;
      destx += thisNode.offsetLeft;
      desty += thisNode.offsetTop;
    }
	
	
	 // --- added by Joel Brehm for UNL Research News ------------------------------------------------------------------------------------------------------------------- 
	if(anchor == "next"){
		
		if(yScroll < notesLink){
			anchor = "newsnotes";
			desty = notesLink;
		}
		else if((yScroll >= notesLink) && (yScroll < resourcesLink)){
				anchor = "resources";
				desty = resourcesLink;
		}
		else if((yScroll >= resourcesLink) && (yScroll < aboutLink)){
				anchor = "about";
				desty = aboutLink;
		}
		
	}
	
	if(anchor == "previous"){
		
		if(yScroll <= notesLink){
			anchor = "home";
			desty = 0;
		}
		else if((yScroll >= notesLink) && (yScroll < resourcesLink)){
			anchor = "newsnotes";
			desty = notesLink;
		}
		else if(yScroll == resourcesLink){
			anchor = "newsnotes";
			desty = notesLink;
		}
		else if(yScroll > resourcesLink){
			anchor = "resources";
			desty = resourcesLink;
		}
		
	}
	 // --------end added code----------------------------------------------------------------------------------------------------------------------------------------------------------- 
	

    // Stop any current scrolling
    clearInterval(ss.INTERVAL);
  
    cypos = ss.getCurrentYPos();
  
    ss_stepsize = parseInt((desty-cypos)/ss.STEPS);
    ss.INTERVAL =
setInterval('ss.scrollWindow('+ss_stepsize+','+desty+',"'+anchor+'")',10);
  
    // And stop the actual click happening
    if (window.event) {
      window.event.cancelBubble = true;
      window.event.returnValue = false;
    }
    if (e && e.preventDefault && e.stopPropagation) {
      e.preventDefault();
      e.stopPropagation();
    }
  },

  scrollWindow: function(scramount,dest,anchor) {
	
	//added by Joel Brehm 
	document.getElementById('footer').style.display = 'none';
   
    wascypos = ss.getCurrentYPos();
    isAbove = (wascypos < dest);
    window.scrollTo(0,wascypos + scramount);
    iscypos = ss.getCurrentYPos();
    isAboveNow = (iscypos < dest);
    if ((isAbove != isAboveNow) || (wascypos == iscypos)) {
      // if we've just scrolled past the destination, or
      // we haven't moved from the last scroll (i.e., we're at the
      // bottom of the page) then scroll exactly to the link
      window.scrollTo(0,dest);
      // cancel the repeating timer
      clearInterval(ss.INTERVAL);
      // and jump to the link directly so the URL's right
      location.hash = anchor;
	
	 // --- added by Joel Brehm for UNL Research News ------------------------------------------------------------------------------------------------------------------- 
	
	//document.getElementById('footer').style.display = 'block';
	//$('footer').fade({ duration: 0.2, from: 0, to: 1 });
	$('footer').appear({ duration: 0.2 });
	if((anchor != 'newsnotes') && (anchor != 'resources') && (anchor != 'home') && (anchor != 'about')){
		
		newAnchor = anchor + 'E';
		new Effect.Highlight(newAnchor, { startcolor: '#CCCCCC',endcolor: '#f3f7f9', restoreColor: '#ffffff', duration:2 });
	}

	 // --------end added code----------------------------------------------------------------------------------------------------------------------------------------------------------- 
   }
  },

  getCurrentYPos: function() {
    if (document.body && document.body.scrollTop)
      return document.body.scrollTop;
    if (document.documentElement && document.documentElement.scrollTop)
      return document.documentElement.scrollTop;
    if (window.pageYOffset)
      return window.pageYOffset;
    return 0;
  },

  addEvent: function(elm, evType, fn, useCapture) {
    // addEvent and removeEvent
    // cross-browser event handling for IE5+,  NS6 and Mozilla
    // By Scott Andrew
    if (elm.addEventListener){
      elm.addEventListener(evType, fn, useCapture);
      return true;
    } else if (elm.attachEvent){
      var r = elm.attachEvent("on"+evType, fn);
      return r;
    } else {
      alert("Handler could not be removed");
    }
  }
  

}


	 // --- added by Joel Brehm for UNL Research News ------------------------------------------------------------------------------------------------------------------- 
function findDestLink(destinationLink){
	// Find the destination's position
    var destx = destinationLink.offsetLeft; 
    var desty = destinationLink.offsetTop;
    var thisNode = destinationLink;
    while (thisNode.offsetParent && 
          (thisNode.offsetParent != document.body)) {
      thisNode = thisNode.offsetParent;
      destx += thisNode.offsetLeft;
      desty += thisNode.offsetTop;
    }
	return desty;
 }
 
function getScrollHeight()
{
   var h = window.pageYOffset ||
           document.body.scrollTop ||
           document.documentElement.scrollTop;
           
   return h ? h : 0;
} 
	 // --------end added code----------------------------------------------------------------------------------------------------------------------------------------------------------- 


ss.STEPS = 20;

ss.addEvent(window,"load",ss.fixAllLinks);