/* Quicklinks Script for Virginia Tech */

/* ----- GLOBAL VARIABLES ------ */

// MAX_QL_ITEMS: maximum number of items that can be stored in quicklinks
//   Note: the maximum size a cookie is 4KB 
var MAX_QL_ITEMS = '30';

// COOKIE_DOMAIN: Host/ Domain for which the cookie applies
var COOKIE_DOMAIN = "vt.edu";

// QL_ID: ID of the list (UL) that will contain the quicklinks
var QL_ID = "vt_ql_list";

// QL_COOKIE_NAME: Name of the cookie that will be stored
var QL_COOKIE_NAME = "vt_quick_links";

// names of Default and all items (used as a selector to determine
//    what array to use in function createQL() )
var QL_DEFAULT_NAME = "default_ql";
var QL_ALL_NAME = "all_ql";

// name of the Customize Quicklinks label
var CUSTOMIZE_NAME = "Customize Quicklinks";
// URL to the Quicklinks customize page
// Set to '' if you don't want to automatically add it to QL_ID
var CUSTOMIZE_URL = "http://www.vt.edu/customize_quicklinks.php";

// default_ql and az_index are predefined 2d arrays with a list of urls and titles
// this checks to see if it exists, else sets the global var to be blank if it doesn't
// az_index is defined in quicklinks_customize.js
if (typeof(qldefaults)!="undefined"){
	var QL_DEFAULT = qldefaults;
}else{
	var QL_DEFAULT = '';
}

// ----- END GLOBAL VARIABLE DEFINITIONS -----
addLoadEvent(checkQLCookie);

// will check to see if a quicklink cookie exists, if not will load defaults
function checkQLCookie(){
	var quicklinks=readCookie(QL_COOKIE_NAME);
	if (quicklinks!=null && quicklinks!="")
		{loadQLCookie();}
	else 
		{createQL();}
}

function createQL(){
	qlItemArray = QL_DEFAULT;
	if (qlItemArray.length > (MAX_QL_ITEMS)){
		alert("You are only allowed to have " + MAX_QL_ITEMS + " in your quicklinks");
	}else{
		// Don't set a cookie unless they specifically save it, hence next line is commented out
		// setQLCookie(qlItemArray);
		if(document.getElementById(QL_ID)){createQLList(qlItemArray, QL_ID);}
	}
}

// Given a string and preset format (currently only cookie)
//   will break that string appropriately and return an array
function createItemArrayFromStr(docStr, format){
	if (format == "cookie"){
	  // unescape cookie before splitting it
		var splitStr = (unescape(docStr)).split("<i>");
		var numItems = (splitStr.length-1)/2;
		var qlItems = new Array(numItems);
		for (i = 0; i<numItems; i++){
			qlItems[i] = new Array(2);
			// Need offset by one b/c first element in split is empty
			qlItems[i][0]=splitStr[(i*2)+1];
			qlItems[i][1]=splitStr[(i*2)+2];
		}
		return qlItems;
	}else{
		alert("unrecognized format");
	}
}
function loadQLCookie(){
	var qlCookie = readCookie(QL_COOKIE_NAME);
	var qlItems = createItemArrayFromStr(qlCookie, "cookie");
	createQLList(qlItems, QL_ID);
}

function setQLCookie(qlItemArray)
{
	var cookieStr = '';
	for (i = 0; i <qlItemArray.length; i++)
	{
		//escape before placing it into the cookie (addresses safari error)
		cookieStr += '<i>'
				+ escape(qlItemArray[i][0])
				+ '<i>'
				+ escape(qlItemArray[i][1]);
	}
	createCookie(QL_COOKIE_NAME, cookieStr, 60);
}

// Given an array of items and a ul id, will add lis of the item to the ul 
// qlItemArray is a 2d array of a title and URL
function createQLList(qlItemArray, elementId){
// element must exist before we do anything to it
  if (document.getElementById(elementId)){
		var qlList = document.getElementById(elementId);
		// clear out anything that may already be there.
		qlList.innerHTML = '';
		var newNode, newItem;
		for (i = 0; i < qlItemArray.length; i++){
					newNode = document.createElement("li"); 
					newItem = '<a href="'
					+ qlItemArray[i][1]
					+ '">'
					+ qlItemArray[i][0]
					+ '</a>';
					newNode.innerHTML = newItem;
					qlList.appendChild(newNode);
		}
		// append the customize name & link to the end of QL_ID
		if (elementId == QL_ID && CUSTOMIZE_URL != '' && CUSTOMIZE_NAME != ''){
					newNode = document.createElement("li"); 
					newItem = '<a href="'
					+ CUSTOMIZE_URL
					+ '">'
					+ CUSTOMIZE_NAME
					+ '</a>';
					newNode.innerHTML = newItem;
					qlList.appendChild(newNode);
		}
	}
}

/* 
-------------------------
Generic Cookie Functions 
-------------------------
*/
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 var expires = "";
	document.cookie = name+"="+value+expires+"; path=/; domain="+COOKIE_DOMAIN;
}

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;
}

function eraseCookie(name) 
{
	createCookie(name,"",(-1));
}
// ----- END Generic Cookie Functions -----


function addLoadEvent(func) {
	var oldOnLoad = window.onload
	if (typeof window.onload != 'function') 
	{
		window.onload = func;
	}
	else {
		window.onload = function() {
			oldOnLoad();
			func();
		}
	}
}
// ------ END DomReady Code -----