// Used to scroll our tabbed view, display our download popup, and display the giant dialog.
// Scroll: Setup Scrolling Stuff
// exemple : source html 
/*
    <ul id="toolbar">
        <li id="sites-tab" class="active"><a href="#sites-pane" onclick="ScrollSection('sites-pane'); return false" title="Sites">Sites</a></li>
    </ul>

<div id="frame">
    <div id="scroller">
        <div id="content">
            <div id="sites-pane">1</div>
            <div id="files-pane">2</div>
		</div>
	</div>
</div>

ScrollArrow('left'); -> suivant
ScrollArrow('right'); -> précédent
ScrollSection('files-pane',); ---> aller au prochain désigné

//pour l'appeler

initSliderPage("books-pane","-tab","-pane","sites-pane","scroller","toolbar","20","horizontal");
*/


var currentSection; //onglet par defaut
var tabTag //prefixe de l'onget qui change
var paneTag //prefixe des pages
var scrollanim = {time:0, begin:0, change:0.0, duration:0.0, element:null, timer:null};
//css pour les onglet pour voir qui est actif ou pas
var cssOngletActif='active';
var cssOngletInactif='inactive';
var directionSlide; //direction vertical ou horizontal
var offset; //nom de la div qui commence 
var scrollArea; //id de la zone scrollé ....
var toolbar //id du div qui contient les onglets ...


function initSliderPage(ongletDefaut,prefixOnglet,prefixPage,offsetId,scrollId,zoneOnglet,duree,direction,cssActif,cssInactif){
     tabTag = prefixOnglet;
     paneTag = prefixPage;
     scrollanim.duration = duree;
     directionSlide=direction;
     offset=offsetId;
     scrollArea=scrollId;
     toolbar=zoneOnglet;
     if(cssActif && cssActif!='') cssOngletActif=cssActif;
     if(cssInactif && cssInactif!='') cssOngletInactif=cssInactif;
     
     
     ScrollSection(ongletDefaut);
}


// Scroll the page manually to the position of element "link", passed to us.
function ScrollSection(link){
	
    // Store the last section, and update the current section
	if (currentSection == link) return;
	
    lastSection = currentSection;
	currentSection = link;

	// Change the section highlight.
	// Extract the root section name, and use that to change the background image to 'top', revealing the alt. state
    sectionTab = currentSection.split("-")[0] + tabTag;
    if(document.getElementById(sectionTab)) document.getElementById(sectionTab).className = cssOngletActif;
    if (lastSection) {
	    lastTab = lastSection.split("-")[0] + tabTag;
	    if(document.getElementById(lastTab)) document.getElementById(lastTab).className = cssOngletInactif;
	}

	// Get the element we want to scroll, get the position of the element to scroll to
	theScroll = document.getElementById(scrollArea);

    position = findElementPos(document.getElementById(link));

	// Get the position of the offset div -- the div at the far left.
	// This is the amount we compensate for when scrolling
    if(directionSlide=="horizontal"){
        if (offset != "") {
    		offsetPos = findElementPos(document.getElementById(offset));
    		position[0] = position[0] - offsetPos[0];
    	}
        scrollStart(theScroll, theScroll.scrollLeft, position[0], "horiz");
   
   }else{
       	if (offset != "") {
    		offsetPos = findElementPos(document.getElementById(offset));
    		position[0] = position[1] - offsetPos[1];
    	}     
        
        scrollStart(theScroll, theScroll.scrollTop, position[0], "vert");
    }
    
	// return false;
}


// Scroll the page using the arrows
function ScrollArrow(direction) {

	toolbarElem = document.getElementById(toolbar);
	toolbarNames = new Array();

	// Find all the <li> elements in the toolbar, and extract their id's into an array.

	if (toolbarElem && toolbarElem.hasChildNodes())
	{
		var children = toolbarElem.childNodes;
		for (var i = 0; i < children.length; i++)
		{
			if (toolbarElem.childNodes[i].tagName == "LI") {
				toolbarNames.push(toolbarElem.childNodes[i].id.split("-")[0]);
			}
		}
	}

	// Now iterate through our array of tab names, find matches, and determine where to go.

	for (var i = 0; i < toolbarNames.length; i++) {
		if (toolbarNames[i] == currentSection.split("-")[0]) {
			if (direction == "left") {
				if (i - 1 < 0) {
					gotoTab = toolbarNames[toolbarNames.length - 1];
				} else {
					gotoTab = toolbarNames[i - 1];
				}
			} else {
				if ((i + 1) > (toolbarNames.length - 1)) {
					gotoTab = toolbarNames[0];
				} else {
					gotoTab = toolbarNames[i + 1];
				}
			}
		}
	}

	// Go to the section name!
	if(typeof(gotoTab)!="undefined") ScrollSection(gotoTab+paneTag);
}

//
// Animated Scroll Functions
// Scrolls are synchronous -- only one at a time.
//

function scrollStart(elem, start, end, direction){
	//console.log("scrollStart from "+start+" to "+end+" in direction "+direction);

	if (scrollanim.timer != null) {
		clearInterval(scrollanim.timer);
		scrollanim.timer = null;
	}
	scrollanim.time = 0;
	scrollanim.begin = start;
	scrollanim.change = end - start;
    //scrollanim.duration = 20;
	scrollanim.element = elem;

	if (direction == "horiz") {
		scrollanim.timer = setInterval("scrollHorizAnim();", 15);
	}
	else {
		scrollanim.timer = setInterval("scrollVertAnim();", 15);
	}
}

// pour scroller verticalment
function scrollVertAnim(){
	if (scrollanim.time > scrollanim.duration) {
		clearInterval(scrollanim.timer);
		scrollanim.timer = null;
	}
	else {
		move = sineInOut(scrollanim.time, scrollanim.begin, scrollanim.change, scrollanim.duration);
        scrollanim.element.scrollTop = move;
		scrollanim.time++;
	}
}

// pour scroller horizontalement
function scrollHorizAnim()
{
	if (scrollanim.time > scrollanim.duration) {
		clearInterval(scrollanim.timer);
		scrollanim.timer = null;
	}
	else {
		move = sineInOut(scrollanim.time, scrollanim.begin, scrollanim.change, scrollanim.duration);
        scrollanim.element.scrollLeft = move;
		scrollanim.time++;
	}
}

// Find the Y position of an element on a page
// Return Y and X as an array
function findElementPos(elemFind)
{
	var elemX = 0;
	var elemY = 0;
	do {
		elemX += elemFind.offsetLeft;
		elemY += elemFind.offsetTop;
	} while ( elemFind = elemFind.offsetParent )


	return Array(elemX, elemY);
}

// Utility: Math functions for animation calucations - From http://www.robertpenner.com/easing/
//
// t = time, b = begin, c = change, d = duration
// time = current frame, begin is fixed, change is basically finish - begin, duration is fixed (frames),
function sineInOut(t, b, c, d){
	return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
}