// Copyright (c) 2009 sakuratan
// Released under the MIT License.
// http://www.opensource.org/licenses/mit-license.php

(function($) {
    var orig_ajax_func = $.ajax;
    var page_tracker = null;
    var options = {
	trackEventCategory: 'jQuery.ajax',
	autoTracking: true
    };
    var queue = [];

    $.ajaxGA = {};

    $.ajaxGA.getOption = function(name) {
	return options[name];
    }

    $.ajaxGA.setOption = function(name, value) {
	if (typeof(name) == 'string') {
	    if (typeof(options[name]) != 'undefined') {
		options[name] = value;
	    }
	} else {
	    for (key in name) {
		if (typeof(options[key]) != 'undefined') {
		    options[key] = name[key];
		}
	    }
	}
    }

    $.ajaxGA.init = function(trackingId, callbackOrPageview) {
	$(function() {
	    orig_ajax_func.apply($, [{
		type: 'GET',
		url: (document.location.protocol == "https:" ?
		      "https://ssl" : "http://www") +
		     '.google-analytics.com/ga.js',
		cache: true,
		dataType: 'script',
		success: function() {
		    if (typeof(_gat) == 'undefined') {
			throw new Error('Missing _gat');
		    }
		    page_tracker = _gat._getTracker(trackingId);

		    if (callbackOrPageview) {
			if ($.isFunction(callbackOrPageview)) {
			    callbackOrPageview(page_tracker);
			} else {
			    if (typeof(callbackOrPageview) == 'string') {
				page_tracker._trackPageview(callbackOrPageview);
			    } else {
				page_tracker._trackPageview();
			    }
			}
		    }

		    var q;
		    while (q = queue.shift()) {
			q(page_tracker);
		    }
		}
	    }]);
	});
    };

    $.ajaxGA.doPageTrack = function(callback) {
	if (page_tracker == null) {
	    queue.push(callback);
	} else {
	    callback(page_tracker);
	}
    };

    function ajax_replacement(params) {
	if (options.autoTracking) {
	    if (typeof(params.trackGA) != 'undefined' && !params.trackGA) {
		return orig_ajax_func.apply(this, [params]);
	    }
	} else {
	    if (!params.trackGA) {
		return orig_ajax_func.apply(this, [params]);
	    }
	}

	var orig_complete = params.complete;
	var orig_error = params.error;

	params.complete = function(xhr, status) {
	    if (orig_complete) {
		orig_complete(xhr, status);
	    }

	    if (params.trackGA) {
		if ($.isFunction(params.trackGA)) {
		    $.ajaxGA.doPageTrack(params.trackGA);
		} else {
		    $.ajaxGA.doPageTrack(function(t) {
			t._trackPageview(params.trackGA);
		    });
		}
	    } else {
		$.ajaxGA.doPageTrack(function(t) {
		    t._trackEvent(options.trackEventCategory,
				  (params.type ? params.type : 'GET'),
				  params.url);
		});
	    }

	    params.complete = orig_complete;
	    params.error = orig_error;
	};

	params.error = function(xhr, status, e) {
	    if (orig_error) {
		orig_error(xhr, status, e);
	    }
	    params.complete = orig_complete;
	    params.error = orig_error;
	};

	return orig_ajax_func.apply(this, [params]);
    }

    $.ajaxGA.enable = function() {
	$.extend({
	    ajax: ajax_replacement
	});
    };

    $.ajaxGA.disable = function() {
	$.extend({
	    ajax: orig_ajax_func
	});
    };

    $.ajaxGA.enable();
})(jQuery);