(function (jQuery) {
    jQuery.StickyTableHeaders = function (el, options) {
        // To avoid scope issues, use 'base' instead of 'this'
        // to reference this class from internal events and functions.
        var base = this;

        // Access to jQuery and DOM versions of element
        base.$el = jQuery(el);
        base.el = el;

        // Add a reverse reference to the DOM object
        base.$el.data('StickyTableHeaders', base);

        base.init = function () {
            base.options = jQuery.extend({}, jQuery.StickyTableHeaders.defaultOptions, options);

            base.$el.each(function () {
                var $this = jQuery(this);
                $this.wrap('<div class="divTableWithFloatingHeader" style="position:relative"></div>');

                var originalHeaderRow = jQuery('tr:first', this);
                originalHeaderRow.before(originalHeaderRow.clone());
                var clonedHeaderRow = jQuery('tr:first', this);

                clonedHeaderRow.addClass('tableFloatingHeader');
                clonedHeaderRow.css('position', 'fixed');
                clonedHeaderRow.css('top', '0px');
                clonedHeaderRow.css('left', $this.css('margin-left'));
                clonedHeaderRow.css('display', 'none');

                originalHeaderRow.addClass('tableFloatingHeaderOriginal');

                // enabling support for jquery.tablesorter plugin
                $this.bind('sortEnd', function (e) { base.updateCloneFromOriginal(originalHeaderRow, clonedHeaderRow); });
            });

            base.updateTableHeaders();
            jQuery(window).scroll(base.updateTableHeaders);
            jQuery(window).resize(base.updateTableHeaders);
        };

        base.updateTableHeaders = function () {
            base.$el.each(function () {
                var $this = jQuery(this);
                var $window = jQuery(window);

                var fixedHeaderHeight = isNaN(base.options.fixedOffset) ? base.options.fixedOffset.height() : base.options.fixedOffset;

                var originalHeaderRow = jQuery('.tableFloatingHeaderOriginal', this);
                var floatingHeaderRow = jQuery('.tableFloatingHeader', this);
                var offset = $this.offset();
                var scrollTop = $window.scrollTop() + fixedHeaderHeight;
                var scrollLeft = $window.scrollLeft();

                if ((scrollTop > offset.top) && (scrollTop < offset.top + $this.height())) {
                    floatingHeaderRow.css('top', fixedHeaderHeight + 'px');
                    floatingHeaderRow.css('margin-top', 0);
                    floatingHeaderRow.css('left', (offset.left - scrollLeft) + 'px');
                    floatingHeaderRow.css('display', 'block');

                    base.updateCloneFromOriginal(originalHeaderRow, floatingHeaderRow);
                }
                else {
                    floatingHeaderRow.css('display', 'none');
                }
            });
        };

        base.updateCloneFromOriginal = function (originalHeaderRow, floatingHeaderRow) {
            // Copy cell widths and classes from original header
            jQuery('th', floatingHeaderRow).each(function (index) {
                $this = jQuery(this);
                var origCell = jQuery('th', originalHeaderRow).eq(index);
                $this.removeClass().addClass(origCell.attr('class'));
                $this.css('width', origCell.width());
            });

            // Copy row width from whole table
            floatingHeaderRow.css('width', originalHeaderRow.width());
        };

        // Run initializer
        base.init();
    };

    jQuery.StickyTableHeaders.defaultOptions = {
        fixedOffset: 0
    };

    jQuery.fn.stickyTableHeaders = function (options) {
        return this.each(function () {
            (new jQuery.StickyTableHeaders(this, options));
        });
    };

})(jQuery);