// PRELOADING IMAGES
var imgcount = directories.length;
if (document.images) {
    imageon = [];
    imageoff = [];
    for (var i=1; i<=imgcount; i++) {
        front = "images/front/"+directories[i-1]+".jpg";
        spine = "images/spine/"+directories[i-1]+".jpg";
        imageon['img'+i] = new Image();
        imageon['img'+i].src = front;
        imageoff['img'+i] = new Image();
        imageoff['img'+i].src = spine;
    }
}

function handleOver() {
    if (document.images)
        document.imgName.src=img_on.src;
}

function handleOut() {
    if (document.images)
        document.imgName.src=img_off.src;
}

function hideAll() {
    $('.directories img').each(function(){
        var name = $(this).attr('name');
        var source = imageoff[name].src;
        if ($(this).attr('src') != source) {
            $(this).attr('src', source);
        }
    });
}

function movr(k) {
    hideAll();
    $('img[name=img'+k+']').attr('src', imageon['img'+k].src);
}

function oc(a)
{
    var o = {};
    for(var i=0;i<a.length;i++)
    {
        o[a[i]]='';
    }
    return o;
}

function arrayconvert(a)
{
    var o = {};
    for(var i=0;i<a.length;i++)
    {
        o[a[i]]=i+1;
    }
    return o;
}

function intval (mixed_var, base) {
    var type = typeof( mixed_var );
 
    if (type === 'boolean') {
        return (mixed_var) ? 1 : 0;
    } else if (type === 'string') {
        tmp = parseInt(mixed_var, base || 10);
        return (isNaN(tmp) || !isFinite(tmp)) ? 0 : tmp;
    } else if (type === 'number' && isFinite(mixed_var) ) {
        return Math.floor(mixed_var);
    } else {
        return 0;
    }
}

function qld() {
    $('.bookshelf').each(function(){
        if($(this).children().first().attr('alt') in oc(qlddirectories)){
            $(this).css({
                'display':'inline'
            });
        } else {
            $(this).css({
                'display':'none'
            });
        }
    });
    var dircount = qlddirectories.length;
    var h = intval(dircount / 2);
    var median;

    if(dircount % 2 == 0) {
        median = intval((h + (h-1)) / 2);
    } else {
        median = h;
    }
    hideAll();
    var whichdir = qlddirectories[median];
    var obj = arrayconvert(alldirectories);
    var name = 'img'+obj[whichdir];
    $('img[name='+name+']').attr('src', imageon[name].src);
}

function nsw() {
    $('.bookshelf').each(function(){
        if($(this).children().first().attr('alt') in oc(nswdirectories)){
            $(this).css({
                'display':'inline'
            });
        } else {
            $(this).css({
                'display':'none'
            });
        }
    });
    var dircount = nswdirectories.length;
    var h = intval(dircount / 2);
    var median;

    if(dircount % 2 == 0) {
        median = intval((h + (h-1)) / 2);
    } else {
        median = h;
    }
    hideAll();
    var whichdir = nswdirectories[median];
    var obj = arrayconvert(alldirectories);
    var name = 'img'+obj[whichdir];
    $('img[name='+name+']').attr('src', imageon[name].src);
}

function nt() {
    $('.bookshelf').each(function(){
        if($(this).children().first().attr('alt') in oc(ntdirectories)){
            $(this).css({
                'display':'inline'
            });
        } else {
            $(this).css({
                'display':'none'
            });
        }
    });
    var dircount = ntdirectories.length;
    var h = intval(dircount / 2);
    var median;

    if(dircount % 2 == 0) {
        median = intval((h + (h-1)) / 2);
    } else {
        median = h;
    }
    hideAll();
    var whichdir = ntdirectories[median];
    var obj = arrayconvert(alldirectories);
    var name = 'img'+obj[whichdir];
    $('img[name='+name+']').attr('src', imageon[name].src);
}

function showAll() {
    $('.bookshelf').each(function(){
        $(this).css({
            'display':'inline'
        });
    });
    var dircount = alldirectories.length;
    var h = intval(dircount / 2);
    var median;

    if(dircount % 2 == 0) {
        median = intval((h + (h-1)) / 2);
    } else {
        median = h;
    }
    hideAll();
    var whichdir = alldirectories[median];
    var obj = arrayconvert(alldirectories);
    var name = 'img'+obj[whichdir];
    $('img[name='+name+']').attr('src', imageon[name].src);
}