// $Id: tableheader.js,v 1.16.2.2 2009/03/30 12:48:09 goba Exp $

Drupal.tableHeaderDoScroll = function() {

  if (typeof(Drupal.tableHeaderOnScroll)=='function') {

    Drupal.tableHeaderOnScroll();

  }

};

Drupal.behaviors.tableHeader = function (context) {

  // This breaks in anything less than IE 7. Prevent it from running.

  if (jQuery.browser.msie && parseInt(jQuery.browser.version, 10) < 7) {

    return;

  }

  // Keep track of all cloned table headers.

  var headers = [];

  $('table.sticky-enabled thead:not(.tableHeader-processed)', context).each(function () {

    // Clone thead so it inherits original jQuery properties.

    var headerClone = $(this).clone(true).insertBefore(this.parentNode).wrap('<table class="sticky-header"></table>').parent().css({

      position: 'fixed',

      top: '0px'

    });

    headerClone = $(headerClone)[0];

    headers.push(headerClone);

    // Store parent table.

    var table = $(this).parent('table')[0];

    headerClone.table = table;

    // Finish initialzing header positioning.

    tracker(headerClone);

    $(table).addClass('sticky-table');

    $(this).addClass('tableHeader-processed');

  });

  // Define the anchor holding var.

  var prevAnchor = '';

  // Track positioning and visibility.

  function tracker(e) {

    // Save positioning data.

    var viewHeight = document.documentElement.scrollHeight || document.body.scrollHeight;

    if (e.viewHeight != viewHeight) {

      e.viewHeight = viewHeight;

      e.vPosition = $(e.table).offset().top - 4;

      e.hPosition = $(e.table).offset().left;

      e.vLength = e.table.clientHeight - 100;

      // Resize header and its cell widths.

      var parentCell = $('th', e.table);

      $('th', e).each(function(index) {

        var cellWidth = parentCell.eq(index).css('width');

        // Exception for IE7.

        if (cellWidth == 'auto') {

          cellWidth = parentCell.get(index).clientWidth +'px';

        }

        $(this).css('width', cellWidth);

      });

      $(e).css('width', $(e.table).css('width'));

    }

    // Track horizontal positioning relative to the viewport and set visibility.

    var hScroll = document.documentElement.scrollLeft || document.body.scrollLeft;

    var vOffset = (document.documentElement.scrollTop || document.body.scrollTop) - e.vPosition;

    var visState = (vOffset > 0 && vOffset < e.vLength) ? 'visible' : 'hidden';

    $(e).css({left: -hScroll + e.hPosition +'px', visibility: visState});

    // Check the previous anchor to see if we need to scroll to make room for the header.

    // Get the height of the header table and scroll up that amount.

    if (prevAnchor != location.hash) {

      if (location.hash != '') {

        var offset = $('td' + location.hash).offset();

        if (offset) {

          var top = offset.top;

          var scrollLocation = top - $(e).height();

          $('body, html').scrollTop(scrollLocation);

        }

      }

      prevAnchor = location.hash;

    }

  }

  // Only attach to scrollbars once, even if Drupal.attachBehaviors is called

  //  multiple times.

  if (!$('body').hasClass('tableHeader-processed')) {

    $('body').addClass('tableHeader-processed');

    $(window).scroll(Drupal.tableHeaderDoScroll);

    $(document.documentElement).scroll(Drupal.tableHeaderDoScroll);

  }

  // Track scrolling.

  Drupal.tableHeaderOnScroll = function() {

    $(headers).each(function () {

      tracker(this);

    });

  };

  // Track resizing.

  var time = null;

  var resize = function () {

    // Ensure minimum time between adjustments.

    if (time) {

      return;

    }

    time = setTimeout(function () {

      $('table.sticky-header').each(function () {

        // Force cell width calculation.

        this.viewHeight = 0;

        tracker(this);

      });

      // Reset timer

      time = null;

    }, 250);

  };

  $(window).resize(resize);

};