/*

TagCloud jQuery plugin

A dynamic JavaScript tag/keyword cloud plugin for jQuery, designed to use with Ajax:
the cloud is generated from an array.

MIT license.

Schaffer Krisztián
http://woophoo.com

Usage:
------

Call it on a jQuery object created from one element and pass an array of
objects with "Keyword" and "Weight" attributes. E.g.:

var tags = [{Keyword: "computers", Weight: 56}, {Keyword: "mobile" , Weight :12}, ... ];
$("#tagcloud"}.tagCloud(tags);


Configuration:
--------------
Optionally you can pass a configuration object to tagCloud as the second
parameter. Allowed settings are:

sort: Comparator function used for sort the tags before displaying, or false if
   no sorting needed.

   default: sort by Keyword text using
          function (a, b) {return a.Keyword < b.Keyword ? -1 : (a.Keyword == b.Keyword ? 0 : 1)

click: Event handler which receives the Keyword name as first parameter
   and the original click event as second. The preventDefault() is called
   on event before passing so don't bother.

   default: does nothing:
          function(Keyword, event) {}


maxFontSizeEm: Size of the largest Keyword in the cloud in css 'em'. The smallest
   one's size is 1em so this value is the ratio of the smallest and largest
   sizes.

   default: 4


Styling:
--------
 The plugin adds the "tagcloudlink" class to the generated tag links. Note that
an "&nbsp;" is generated between the links too.


Originally based on DynaCloud v3 by
Johann Burkard
<http://johannburkard.de>
<mailto:jb@eaio.com>

CHANGES:
05 sept. 2008
- Improved normalization algorithm - better looking font sizes
- New settings: click, maxFontSizeEm
- Documentation

04 sept. 2008
- Initial version

*/

jQuery.fn.tagCloud = function(cl, givenOptions) { //return this.each( function() { //like a real jQuery plugin: run on on each element
   if (!cl || !cl.length)
      return this;

   // Default settings:
   var defaults = {
   sort: function(a, b) { return a.Keyword < b.Keyword ? -1 : (a.Keyword == b.Keyword ? 0 : 1) }, //default sorting: abc
   click: function(Keyword) { },
      maxFontSizeEm: 4
   }

   var options = {};
   jQuery.extend(options, defaults, givenOptions);

   // calculating the max and min count values
   var max = -1;
   var min = cl[0].Weight;
   $.each(cl, function(i, n) {
   max = Math.max(n.Weight, max);
   min = Math.min(n.Weight, min);
   });

   if (options.sort) {
      cl.sort(options.sort);
   }

   //Normalization helper
   var diff = ( max == min ? 1    // if all values are equal, do not divide by zero
                           : (max - min) / (options.maxFontSizeEm - 1) ); //optimization: Originally we want to divide by diff
                           // and multiple by maxFontSizeEm - 1 in getNormalizedSize.
   function getNormalizedSize(Weight) {
       return 1 + (Weight - min) / diff;
   }

   // Generating the output
   this.empty();
   for (var i = 0; i < cl.length; ++i) {
       var Keyword = cl[i].Keyword;
      var tagEl = jQuery('<a href="" class="tagcloudlink" style="font-size: '
                           + getNormalizedSize(cl[i].Weight)
                           + 'em">' + Keyword + '<\/a>')
                  .data('Keyword', Keyword);

      if (options.click) {
         tagEl.click(function(event) {
            event.preventDefault();
            options.click(jQuery(event.target).data('Keyword'), event);
         });
      }
      this.append(tagEl).append(" ");
   }
   return this;
//})
}