var slideCycle = function(datas) {
    datas.start = datas.start - 1 || 0;
    datas.animDiv = datas.animDiv || 5;
    datas.animDelay = datas.animDelay || 40;
    var slideCount = 0;

    var context, items, prev, next, css = datas.direction || 'left', itemsNb = 0, timer, inAnim = false, iRef = false, where, lastMove, tabs = [], tabsPos = [], tabsPosTo = [];

    function getElements() {
        if(iRef === false) {
            for(var i = datas.start; i < (datas.itemsDisplayed + datas.start); i++) {tabs.push(items[verifIndex(i)]);}
        } else if(!lastMove || where == lastMove) {
            if(where == 'next') {
                if(lastMove) {tabs.shift();}
                tabs.push(items[iRef]);
            } else {
                if(lastMove) {tabs.pop();}
                tabs.unshift(items[iRef]);
            }
        }
        if(lastMove) {datas.start = 0;}
        reposition();
    }    

    function computeTabs() {
        var i = -1, l = tabs.length, move = where == 'next' ? - datas.move : datas.move;
        while(++i < l) {
            tabsPos[i] = parseInt(tabs[i].style[css]);
            tabsPosTo[i] = tabsPos[i] + move;
        }
    }

    

    function reposition() {
        if(where) {
            if(where == 'next') {var i = tabs.length - 1, move = datas.move * datas.itemsDisplayed;}
            else {var i = 0, move = - datas.move;}
            tabs[i].style[css] = move +'px';
        } else {
            for(var i = 0; i < datas.itemsDisplayed; i++) {tabs[i].style[css] = (i * datas.move) +'px';}
        }
    }

    function verifIndex(i) {
        if(i >= itemsNb) {i = i - itemsNb;}
        else if(i < 0) {i = i + itemsNb;}
        return i;
    }    

    function slideEnd() {
        tabs[where == 'next' ? 0 : datas.itemsDisplayed].style[css] = datas.offScreen +'px';
        clearTimeout(timer);
        inAnim = false;
        slideCount++;
        if(slideCount < datas.nbMove) {
            //console.log('current where : '+where);
            slideStart('e', where);
        } else {
            slideCount = 0;
        }
    }    

    function slideCheck(cur, pos) {
        return where == 'next' ? cur <= pos : cur >= pos;
    }    

    function slideCompute(cur, pos) {
        //var nb = cur + Math[where == 'next' ? 'floor' : 'ceil']((pos - cur) / datas.animDiv);
        //console.log(slideCount);
        if(slideCount == (datas.nbMove - 1)) {
            var nb = cur + Math[where == 'next' ? 'floor' : 'ceil']((pos - cur) / datas.animDiv);
        } else {
            var nb = cur;
            where == 'next' ? nb -= 36 : nb += 36;
        }
        return nb;
    }    

    function slide() {
        for(var i = 0, tab; tab = tabs[i]; i++) {
            var cur = parseInt(tab.style[css]);
            if(slideCheck(cur, tabsPosTo[i])) {
                tab.style[css] = tabsPosTo[i] +'px';
                if(i == datas.itemsDisplayed) {slideEnd();}
            } else {
                tab.style[css] = slideCompute(cur, tabsPosTo[i]) +'px';
                if(i == datas.itemsDisplayed) {timer = setTimeout(slide, datas.animDelay);}
            }
        }
    }    

    function slideStart(e, moveDirection) {
        if(inAnim) {return false;}
        if(typeof(moveDirection) != 'undefined') {
            where = moveDirection;
        } else {
            where = this == next ? 'next' : 'prev';
            //console.log('where ici : '+where);
        }
        if(where == 'next') {
            iRef = iRef === false ? verifIndex(datas.itemsDisplayed + datas.start) : verifIndex(iRef + (lastMove == 'prev' ? datas.itemsDisplayed : 1));
        } else {
            iRef = iRef === false ? verifIndex(itemsNb - 1 + datas.start) : verifIndex(iRef - (lastMove == 'next' ? datas.itemsDisplayed : 1));
        }
        getElements();
        computeTabs();
        lastMove = where;
        inAnim = true;
        slide();
        return false;
    }    

    context = datas.context.nodeName ? datas.context : document.getElementById(datas.context);
    if(!context) {return;}
    items = datas.items.length && datas.items[0].nodeName ? datas.items : context.getElementsByTagName(datas.items);
    itemsNb = items.length;
    if(itemsNb > datas.itemsDisplayed) {
        next = datas.next.nodeName ? datas.next : document.getElementById(datas.next);
        prev = datas.prev.nodeName ? datas.prev : document.getElementById(datas.prev);
        getElements(items);
        next.onclick = prev.onclick = slideStart;
    }
};