jQuery.fn.choose = function(f) {
    $(this).bind('choose', f);
};


jQuery.fn.file = function() {
    return this.each(function() {
        var btn = $(this);
        var pos = btn.offset();
                                
        function update() {
            pos = btn.offset();
            file.css({
                'top': pos.top,
                'left': pos.left,
                'width': btn.width(),
                'height': btn.height()
            });
        }

        btn.mouseover(update);

        var hidden = $('<div></div>').css({
            'display': 'none'
        }).appendTo('body');

        var file = $('<div><form></form></div>').appendTo('body').css({
            'position': 'absolute',
            'overflow': 'hidden',
            '-moz-opacity': '0',
            'filter':  'alpha(opacity: 0)',
            'opacity': '0',
            'z-index': '2500'      
        });

        var form = file.find('form');
        var input = form.find('input');
        
        function reset() {
            var input = $('<input type="file" multiple>').appendTo(form);
            input.change(function(e) {
                input.unbind();
                input.detach();
                btn.trigger('choose', [input]);
                reset();
            });
        }

        reset();

        function placer(e) {
            form.css('margin-left', e.pageX - pos.left - offset.width);
            form.css('margin-top', e.pageY - pos.top - offset.height + 3);                  
        }

        function redirect(name) {
            file[name](function(e) {
                btn.trigger(name);
            });
        }

        file.mousemove(placer);
        btn.mousemove(placer);

        redirect('mouseover');
        redirect('mouseout');
        redirect('mousedown');
        redirect('mouseup');

        var offset = {
            width: file.width() - 25,
            height: file.height() / 2
        };

        update();
    });
};