/*
* jquery-google-analytics plugin
*
* A jQuery plugin that simplifies event and link tracking.
*
* Features:
*
* - Easy and extensible event and link tracking plugin for jQuery and Google Analytics
* - Automatic internal/external link detection. Default behavior is to skip tracking of internal links.
* - Configurable: skip internal link tracking, metadata extraction using callbacks.
* - Enforces that tracking event handler is added only once.
*
* Copyright (c) 2008 Christian Hellsten
*
* Plugin homepage:
* http://aktagon.com/projects/jquery/google-analytics/
* http://github.com/christianhellsten/jquery-google-analytics/
*
* Examples:
* http://aktagon.com/projects/jquery/google-analytics/examples/
* http://code.google.com/apis/analytics/docs/eventTrackerGuide.html
*
* Repository:
* git://github.com/christianhellsten/jquery-google-analytics.git
*
* Version 1.0.0
*
* Tested with:
* - Mac: Firefox 3
* - Linux: Firefox 3
* - Windows: Firefox 3, Internet Explorer 6
*
* Licensed under the MIT license:
* http://www.opensource.org/licenses/mit-license.php
*
*/
 
(function($) {
  
  /**
* Tracks an event using the given parameters.
*
* The trackEvent method takes four arguments:
*
* category – required string used to group events
* action – required string used to define event type, eg. click, download
* label – optional label to attach to event, eg. buy
* value – optional numerical value to attach to event, eg. price
* skip_internal - optional boolean value. If true then internal links are not tracked.
*
*/
  $.trackEvent = function(category, action, label, value) {
    if(typeof pageTracker == 'undefined') {
      // alert('You need to install the Google Analytics script'); blocked by whatever
    } else {
      pageTracker._trackEvent(category, action, label, value);
    }
  };
 
  /**
* Adds click tracking to elements. Usage:
*
* $('a').track()
*
*/
  $.fn.track = function(options) {
    
    var element = $(this);
    
    // Prevent link from being tracked multiple times
    if (element.hasClass("tracked")) {
      return;
    }
 
     element.addClass("tracked");
 
    // Add click handler to all matching elements
    return this.each(function() {
      var link   = $(this);
 
      // Use default options, if necessary
      var settings = $.extend({}, $.fn.track.defaults, options);
 
      var category = evaluate(link, settings.category);
      var action = evaluate(link, settings.action);
      var label = evaluate(link, settings.label);
      var value = evaluate(link, settings.value);
      
      var message = "category:'" + category + "' action:'" + action + "' label:'" + label + "' value:'" + value + "'";
      
      debug('Tracking ' + message);
 
      link.click(function() {        
        
        // Should we skip internal links?
        var skip = settings.skip_internal && (link[0].hostname == location.hostname);
      
        if(!skip) {
          $.trackEvent(category, action, label, value);
         debug('Tracked ' + message);
        } else {
          debug('Skipped ' + message);
        }
 
        return true;
      });
    });
 
    /**
* Prints to Firebug console if available.
*/
    function debug(message) {
      if(typeof console != 'undefined') {
        console.debug(message);
      }      
    };
    
    /**
* If second parameter is a string: returns the value of the second parameter.
* If the second parameter is a function: passes the element to the function and returns function's return value.
*/
    function evaluate(element, text_or_function) {
      if(typeof text_or_function == 'function') {
        text_or_function = text_or_function(element);
      }
      return text_or_function;
    };
  };
 
  // Default (overridable) settings
  $.fn.track.defaults = {
    category    : function(element) { return (element[0].hostname == location.hostname) ? 'internal':'external'; },
    action    : 'click',
    label     : function(element) { return element.attr('href') },
    value      : null,
    skip_internal : true
  };
})(jQuery);