_H.imageGallery = function() {

    var DOMgallery              = null;
    var gallery                 = null;
    var scroller, sb            = null;
    var galleryCnt              = null;
    var galleryWidth            = 0;
    var galleryScrolledWidth    = 0;
    var currentImage            = 0;
    var images                  = [];
    var pl, nl                  = null;
    var lsc, rsc                = null;
    var ieOld                   = jQuery.browser.msie && (jQuery.browser.version < 7);

    var enableJsControls = function(id) {

        DOMgallery  = new _H.DOM();
        _H.addClass(gallery, "js");

        /* set decorators and get images total width */
        getImages();
        //addMask();
        //addScrollbar(id);
        addArrows(id);

        /* set links events */
        setArrowsLinkClick(id);

    };

    var addArrows       = function(id) {

        _H.$(id+'_prev_arrow').onclick = function() {
            return goToImage(-1);
        };

        _H.$(id+'_next_arrow').onclick = function() {
            alert('next');
            return goToImage(+1);
        };

        /* var arrowsNode = {
            "ul" : {
                "class": "ig_arrows",

                "li~1" : {
                    "class" : "ig_prev disabled",
                    "a"     : {
                        "id"        : [id, "_prev_arrow"].join(''),
                        "text"      : "Precedente",
                        "title"     : "Precedente",
                        "href"      : "#",
                        "onclick"   : function() { return goToImage(-1); }
                    }
                },
                "li~2" : {
                    "class" : "ig_next",
                    "a"     : {
                        "id"        : [id, "_next_arrow"].join(''),
                        "text"      : "Successiva",
                        "title"     : "Successiva",
                        "href"      : "#",
                        "onclick"   : function() { return goToImage(+1); }
                    }
                }
            }
        };

        DOMgallery.create(arrowsNode).append("into", gallery);
        */
    };

    var setArrowsControl    = function(imagepos) {
        if (imagepos === 0) {
            _H.addClass(pl.parentNode, 'disabled');
            lsc.style.width = [scroller.offsetWidth, 'px'].join('');
            rsc.style.width = [sb.offsetWidth - scroller.offsetWidth, 'px'].join('');
        }
        else {
            lsc.style.width = [scroller.offsetLeft, 'px'].join('');
            rsc.style.width = [sb.offsetWidth - scroller.offsetWidth - scroller.offsetLeft, 'px'].join('');
            _H.removeClass(pl.parentNode, 'disabled');
        };
        //alert(["2 - ", lsc.offsetWidth, rsc.offsetWidth].join(' '));

        if (imagepos >= (galleryWidth - gallery.offsetWidth)) _H.addClass(nl.parentNode, 'disabled');
            else _H.removeClass(nl.parentNode, 'disabled');
    };


    var setArrowsLinkClick = function(id) {


        pl = _H.$([id, '_prev_arrow'].join(''));
        nl = _H.$([id, '_next_arrow'].join(''));

        pl.onclick = function() {
            return (_H.hasClass(this.parentNode, 'disabled'))? false : goToImage(-1);
        };

        nl.onclick = function() {
            return (_H.hasClass(this.parentNode, 'disabled'))? false : goToImage(+1);
        };
    };


    var goToImage = function(inc) {

        var nextImage = currentImage + inc;
        if (images[nextImage] === undefined) return false;

        /* animazione della foto */
        var x1 = images[nextImage]['distanceFromLeft'];
        x1 = Math.min(x1, (galleryWidth - gallery.offsetWidth))
        $(galleryCnt).animate({ left: -x1 }, 800);

        /* animazione della scrollbar */

        /* x1 : galleryWidth = x : scroller.parentNode.offsetWidth */
        /* s1 = Math.floor(x1 * scroller.parentNode.offsetWidth / galleryWidth);
        $(scroller).animate({ left: s1 }, 800 , function() {
            lsc.style.width = [scroller.offsetLeft, 'px'].join('');
            rsc.style.width = [sb.offsetWidth - scroller.offsetLeft - scroller.offsetWidth, 'px'].join('');
            //alert(["3 - ", lsc.offsetWidth, rsc.offsetWidth].join(' '));
        }); */


        currentImage = nextImage;


        /** enable-disable arrows */
        if (x1 >= (galleryWidth - gallery.offsetWidth)) _H.addClass(nl.parentNode, 'disabled');
        else _H.removeClass(nl.parentNode, 'disabled');

        if (x1 === 0) _H.addClass(pl.parentNode, 'disabled');
        else _H.removeClass(pl.parentNode, 'disabled');



        return false;
    };


    var getImages      = function() {
        var img = _H.$$(gallery, "img");
        var j   = img.length;
        for (i=0; i<j; i++) {
            images[i] = {};
            images[i]['width']            = img[i].offsetWidth;
            images[i]['distanceFromLeft'] = (images[i-1] !== undefined)? (images[i-1]['distanceFromLeft'] + images[i-1]['width'] + 0) : 0;
            galleryWidth += (images[i]['width'] + 0);
        };

    };


    return {

        init    : function(idGallery) {

            if (!_H.$(idGallery)) throw "No gallery found.";
            gallery = _H.$(idGallery);
            galleryCnt = _H.$$(gallery, "div")[0];

            setTimeout(function() {
                enableJsControls(idGallery);
            }, 20);
        }
    }


};