/*
	highbeam research styleswitcher v1.0
	(c) 2003 / justin blecher / digital pulp, inc.
	inspired by and based on code from http://www.alistapart.com/articles/alternate/
*/


// == prefs ====================================================================

var ss_cookie_name = "HBRSTYLE";
var ss_cookie_expiration = 365; // days
var ss_naming_convention = ": ";


// == constructors =============================================================

// alternate ss object constructor
function AltStyleSheets() {
	// methods
	this.init = initAltStyleSheets;
	this.checkAvailableProps = checkAvailableProps;
	this.savePreferredStyles = savePreferredStyles;
	this.usePreferredStyles = usePreferredStyles;
	this.convertActiveStylesToString = convertActiveStylesToString;
	this.getValueForProperty = getValueForProperty;

	// properties
	this.available_stylesheets = Array();
	this.available_properties = Array();
} // END: AltStyleSheets()


// stylesheet wrapper constructor
function StyleSheet(ss_obj) {
	// properties
	this.css = ss_obj;

	// methods
	this.activate = function() {
		var ss_name;

		// turn off other alt css first
		for (ss_name in alt_css.available_stylesheets) {
			if (this.getPropertyName() == alt_css.available_stylesheets[ss_name].getPropertyName()) alt_css.available_stylesheets[ss_name].css.disabled = true;
		}

		// re-enable this ss
		this.css.disabled = false;
	};

	this.getPropertyName = function () {
		return this.css.getAttribute("title").substring(0, this.css.getAttribute("title").indexOf(':'));
	};
} // END: StyleSheet()



// == methods ==================================================================

function initAltStyleSheets() {
	var all_link_tags, css_title;

	all_link_tags = document.getElementsByTagName("link");

	// loop through link tags and pick out the ones we want
	for (i=0; i < all_link_tags.length; i++) {
		// if link is a alternate stylesheet
		if ( (all_link_tags[i].getAttribute("rel").indexOf("style") != -1) && (all_link_tags[i].getAttribute("rel").indexOf("alt") != -1) ) {
			css_title = all_link_tags[i].getAttribute("title");
			if (css_title) {
				this.available_stylesheets[css_title] = new StyleSheet(all_link_tags[i]); // add the stylesheet to the list
				this.available_stylesheets[css_title].css.disabled = true; // for ie/win because it thinks that all alt stylesheets are enabled until disabled.
				this.available_properties[this.available_stylesheets[css_title].getPropertyName()] = true; // to avoid duplicate entires for properties
			} // end if css title
		} // end if is css
	} // end for all links

} // end initAltStyleSheets()


function getValueForProperty(prop_to_find) {
	var ss_title;

	for (ss_title in this.available_stylesheets) {
		if (ss_title.indexOf(prop_to_find) != -1) {
			if (this.available_stylesheets[ss_title].css.disabled == false) return ss_title.substring(ss_title.indexOf(' ')+1, ss_title.length);
		}
		ss_title = "";
	} // end for in loop

	return false;
} // END: getValueForProperty()


function checkAvailableProps(prop_to_find) {
	var prop;

	for (prop in this.available_properties) {
		if (prop_to_find == prop) return true;
	}

	return false;
} // END: checkAvailableProps()


function convertActiveStylesToString() {
	var active_ss = new Array();

	for (ss in this.available_stylesheets) {
		if (!this.available_stylesheets[ss].css.disabled) {
			active_ss[active_ss.length] = this.available_stylesheets[ss].css.getAttribute("title");
		}
	}

	return active_ss.join(',');
} // END: convertActiveStylesToPrefs()



// == functions ================================================================

function changeStyleProperty(prop, value){
	var ss_name = prop + ss_naming_convention + value;

	if (!alt_css.checkAvailableProps(prop)) return false;
	alt_css.available_stylesheets[ss_name].activate();

	return true;
} // END: changeStyleProperty()


function usePreferredStyles() {
  var cookie_data, active_ss, parts;

	cookie_data = unescape(readCookie(ss_cookie_name));

	if (cookie_data) {
		active_ss = cookie_data.split(",");
		for (var i=0; i< active_ss.length; i++) {
			parts = active_ss[i].split(ss_naming_convention);
			changeStyleProperty(parts[0] , parts[1]);
			parts = null;
		}
	}
} // END: usePreferredStyles()


function savePreferredStyles() {
  var active_styles, cookie_data;

	active_styles = alt_css.convertActiveStylesToString();
	cookie_data = escape(active_styles);
  createCookie(ss_cookie_name, cookie_data, ss_cookie_expiration);
} // END: savePreferredStyles()


// == cookie utility functions =================================================
/* courtesy of ppk and ala... thanks! */

function createCookie(name,value,days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime() + (days*24*60*60*1000));
    var expires = "; expires=" + date.toGMTString();
  } else expires = "";

   document.cookie = name + "=" + value+expires + "; domain=highbeam.com; path=/";
  // document.cookie = name + "=" + value+expires + ";  path=/";
} // END: createCookie()

function readCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');

  for(var i=0;i < ca.length;i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1, c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }

  return null;
} // END: readCookie()


// == global vars ==============================================================

var alt_css = new AltStyleSheets();
alt_css.init();
alt_css.usePreferredStyles();


window.onunload = function(e) {
	alt_css.savePreferredStyles();
} // END: onunload