var selected = [];
var scrollEffect;

Effect.Scroll = Class.create();
Object.extend(Object.extend(Effect.Scroll.prototype, Effect.Base.prototype), {
  initialize: function(element) {
    this.element = $(element);
    if(!this.element) throw(Effect._elementDoesNotExistError);
    var options = Object.extend({
      x:    0,
      y:    0,
      mode: 'relative'
    }, arguments[1] || {});
    this.start(options);
  },
  setup: function() {
    this.originalLeft = this.element.scrollLeft || 0;
    this.originalTop  = this.element.scrollTop  || 0;
    if(this.options.mode == 'absolute') {
      this.options.x = this.options.x - this.originalLeft;
      this.options.y = this.options.y - this.originalTop;
    }
  },
  update: function(position) {
    this.element.scrollLeft = Math.round(this.options.x  * position + this.originalLeft);
    this.element.scrollTop = Math.round(this.options.y  * position + this.originalTop);
  }
});

function onMenuItemSelected(event) {
	if (scrollEffect && scrollEffect.state == 'running') {
		return;
	}

	if (!event) {
		var event = window.event;
	}
	var eventTarget = window.event ? event.srcElement : event.target;

	var pezzi = eventTarget.id.split('-');
	//pezzi[0] timestamp
	//pezzi[1] seme
	//pezzi[2] "menu"
	
	var menuDelta = eventTarget.offsetTop - selected.offsetTop;

	if(selected[pezzi[1]]) selected[pezzi[1]].className = '';
	selected[pezzi[1]] = eventTarget;
   selected[pezzi[1]].className = 'selected';
   
	var idFragment = pezzi[0] + '-' + pezzi[1] + '-pane';
	var target = $(idFragment);
	
	var scroller = $('div_calendario_mese' + '-' + pezzi[1]);
	var scrollDelta = getLeftLocation(target) - getLeftLocation(scroller) - scroller.scrollLeft - (scroller.getDimensions().width - target.getDimensions().width)/2;

	var scrollEffect = new Effect.Scroll('div_calendario_mese' + '-' + pezzi[1]);

   scrollEffect.start({ x: scrollDelta, y: 0, duration: 0.25 });
	   

	
}

function initScrolling() {
   var i = 0;
   var divs = getElementsByClassName('menu_scrolling');
	divs.each(function(div){
	   var pezzi = div.id.split('-');
      //pezzi[0] "menu_scrolling"
      //pezzi[1] seme
	   menuItems = div.immediateDescendants();
   	menuItems.each(function(menuItem) {
   		menuItem.onclick = onMenuItemSelected;
   	});
   	selected[pezzi[1]] = menuItems[0];
   });
}

function getLeftLocation(element) {
	var x = 0;

	do {
		x += element.offsetLeft;
	} while (element = element.offsetParent)

	return x
}


/*
	Developed by Robert Nyman, http://www.robertnyman.com
	Code/licensing: http://code.google.com/p/getelementsbyclassname/
*/
var getElementsByClassName = function (className, tag, elm){
	if (document.getElementsByClassName) {
		getElementsByClassName = function (className, tag, elm) {
			elm = elm || document;
			var elements = elm.getElementsByClassName(className),
				nodeName = (tag)? new RegExp("\\b" + tag + "\\b", "i") : null,
				returnElements = [],
				current;
			for(var i=0, il=elements.length; i<il; i+=1){
				current = elements[i];
				if(!nodeName || nodeName.test(current.nodeName)) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	else if (document.evaluate) {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = "",
				xhtmlNamespace = "http://www.w3.org/1999/xhtml",
				namespaceResolver = (document.documentElement.namespaceURI === xhtmlNamespace)? xhtmlNamespace : null,
				returnElements = [],
				elements,
				node;
			for(var j=0, jl=classes.length; j<jl; j+=1){
				classesToCheck += "[contains(concat(' ', @class, ' '), ' " + classes[j] + " ')]";
			}
			try	{
				elements = document.evaluate(".//" + tag + classesToCheck, elm, namespaceResolver, 0, null);
			}
			catch (e) {
				elements = document.evaluate(".//" + tag + classesToCheck, elm, null, 0, null);
			}
			while ((node = elements.iterateNext())) {
				returnElements.push(node);
			}
			return returnElements;
		};
	}
	else {
		getElementsByClassName = function (className, tag, elm) {
			tag = tag || "*";
			elm = elm || document;
			var classes = className.split(" "),
				classesToCheck = [],
				elements = (tag === "*" && elm.all)? elm.all : elm.getElementsByTagName(tag),
				current,
				returnElements = [],
				match;
			for(var k=0, kl=classes.length; k<kl; k+=1){
				classesToCheck.push(new RegExp("(^|\\s)" + classes[k] + "(\\s|$)"));
			}
			for(var l=0, ll=elements.length; l<ll; l+=1){
				current = elements[l];
				match = false;
				for(var m=0, ml=classesToCheck.length; m<ml; m+=1){
					match = classesToCheck[m].test(current.className);
					if (!match) {
						break;
					}
				}
				if (match) {
					returnElements.push(current);
				}
			}
			return returnElements;
		};
	}
	return getElementsByClassName(className, tag, elm);
};