// control.js includes general purpose JavaScript routines
// which are loaded into the majority of pages

// functions are listed first followed by routines that run
// when the page loads

// Cookie functions - ex Goodman: JavaScript Handbook

function getCookieVal(offset) {
  var endstr = document.cookie.indexOf (";", offset);
  if (endstr == -1)
    endstr = document.cookie.length;
  return unescape(document.cookie.substring(offset, endstr));
}

function GetCookie(name) {
  var arg = name + "=";
  var alen = arg.length;
  var clen = document.cookie.length;
  var i = 0;
  while (i < clen) {
    var j = i + alen;
	   if (document.cookie.substring(i, j) == arg)
     return getCookieVal (j);
    i = document.cookie.indexOf(" ", i) + 1;
    if (i == 0) break; 
  }
  return null;
}

function SetCookie(name, value) {
  var argv = SetCookie.arguments;
  var argc = SetCookie.arguments.length;
  var expires = (argc > 2) ? argv[2] : null;
  var path = (argc > 3) ? argv[3] : null;
  var domain = (argc > 4) ? argv[4] : null;
  var secure = (argc > 5) ? argv[5] : false;
  document.cookie = name + "=" + escape (value) +
    ((expires == null) ? "" : ("; expires=" + expires.toGMTString())) +
    ((path == null) ? "" : ("; path=" + path)) +
//    ("; path=" + "/") +
	((domain == null) ? "" : ("; domain=" + domain)) +
    ((secure == true) ? "; secure" : "");
}

function DeleteCookie(name) {
  var exp = new Date();
  exp.setTime (exp.getTime() - 1);  // This cookie is history
  var cval = GetCookie (name);
  if (cval != null)
    document.cookie = name + "=" + cval + "; expires=" + exp.toGMTString();
}

// end of Goodman's cookie functions


// change() accepts a string, a position in the string and
// a character to substitute at that position
// it returns a string in which the character at position 'pos'
// in the input string is replaced by character 'ch'
// NB first character in a string is at pos = 0

function change(theString, pos, ch) {
	frontEnd = theString.substring(0, pos)
	backEnd = theString.substring(pos + 1, theString.length)
	return frontEnd + ch + backEnd
}

// stubName() accepts a path and returns the name of the file
// stripped of the extension (usually '.htm')
// a variation using '\' rather than '/' as delimiter is
// required to accommodate MSIE for Windows

function stubName(theFile) {
	if (theFile.lastIndexOf("/") > 1) {
		return theFile.substring(theFile.lastIndexOf("/") + 1, theFile.lastIndexOf("."))
	} else {
		return theFile.substring(theFile.lastIndexOf("\\") + 1, theFile.lastIndexOf("."))
	}	
}

// allowAccess() changes characters in a string from '0' to '1'
// to indicate that the user is permitted to access resources
// the result is stored in the major cookie
// access is released progressively as the user moves

function allowAccess(collection,n1,n2) {
	for (var n = n1; n <= n2; n++) {
		collection = change(collection,n,"1")
	}
	return collection
}


// function to flash JPEG images for email
// used rather than animated GIFs to preserve image quality

function flash() {
	if (flashState == 1) {
		document.images[0].src = flashOff.src
		flashState = 0
	} else {
		document.images[0].src = flashOn.src
		flashState = 1
	}
	timerID = setTimeout("flash()",500)
}

// ---- functions above
// ---- from here down is action


function checkLocation() {

	// first set an expiry date for the persistent cookie

	expdate = new Date()
	expdate.setTime(expdate.getTime() + (30 * 24 * 60 * 60 * 1000))
	// 30 days from now

	// now see who we are and how far we have come in the materials

	cookieName = GetCookie("currentUser")

	// if the currentUser cookie is not null the user has logged in
	// so we need to read and update the tracking cookie
	// the variables stored are:
	// resourceAccess 41 characters to progressively release resources
	// consultAccess 24 characters to release feedback
	// expand 16 characters to control pop-down menu lists
	// emailStatus 1 character for tracking progress in problem 3
	// resumePath variable length path for resuming position

	if (cookieName != null) { 

		cookieValue = GetCookie(cookieName)
		resourceAccess = cookieValue.substring(0,41)
		consultAccess = cookieValue.substring(41,65)
		expand = cookieValue.substring(65,81)
		emailStatus = cookieValue.substring(81,82)
		resumePath = cookieValue.substring(82,cookieValue.length)
		
//		alert(location.href + "\n" + resourceAccess + "\n" + consultAccess + "\n" + expand)
		
	// grab the location of the current page

		shortName = stubName(window.location.pathname)
		
	// test first for a feedback page after completion of a task
	// if so adjust record of completed tasks
	// and adjust consultant access to match	
	// feedback page names are coded to support access control
	// more than one task may be completed at a time	

		if (shortName.length == 4 && shortName.substring(0,2) == "fb") {	
			n1 = (parseInt(shortName.charAt(2)) - 1) * 6
			n2 = (parseInt(shortName.charAt(2)) - 1) * 6 + parseInt(shortName.charAt(3)) - 1
			consultAccess = allowAccess(consultAccess,n1,n2)
		}

	// next test if we are at a desk location and
	// if so adjust record of resources
	// n1 is problem number, n2 is desk number in problem

		if (shortName.substring(0,4) == "desk") {
			if (shortName.charAt(4) == "0") { // home location '00'
				n1 = 0
				n2 = 0
			} else {
				n1 = (parseInt(shortName.charAt(4)) - 1) * 10 + 1
				n2 = (parseInt(shortName.charAt(4)) - 1) * 10 + parseInt(shortName.charAt(5))
			}
			resourceAccess = allowAccess(resourceAccess,n1,n2)

	// if the page is of form 'desknn' this is a frameset definition
	// so mark it as the resume location 
			
			if (shortName.length == 6) {
				resumePath = document.location.href
			}
			
	// problems 3 & 4 include some framesets of form 'desknna'
	// so check for those in addition
			
			if (shortName.length > 6) {
				if(shortName.charAt(6) == "a" && shortName.charAt(7) != "t" && shortName.charAt(7) != "b") {
					resumePath = document.location.href
				}
			}
		}

	// now that variables have been updated write the values back
	// to the main cookie which is used to track the user

	  SetCookie(cookieName, resourceAccess + consultAccess + expand + emailStatus + resumePath,expdate,"/")
		  
	// this cookie is used to locate the correct help screen
	// store the current page location every time it runs
	// except when this is the help page
	// it is need only after login since prior pages call the help contents

		if (shortName.indexOf("help") == -1) {
			SetCookie("PBLtemp",location.href,null,"/")
		}

	}

}

// Macromedia Fireworks functions to handle rollovers

function MM_swapImgRestore() { //v2.0
  if (document.MM_swapImgData != null)
    for (var i=0; i<(document.MM_swapImgData.length-1); i+=2)
      document.MM_swapImgData[i].src = document.MM_swapImgData[i+1];
}

function MM_preloadImages() { //v2.0
  if (document.images) {
    var imgFiles = MM_preloadImages.arguments;
    if (document.preloadArray==null) document.preloadArray = new Array();
    var i = document.preloadArray.length;
    with (document) for (var j=0; j<imgFiles.length; j++) if (imgFiles[j].charAt(0)!="#"){
      preloadArray[i] = new Image;
      preloadArray[i++].src = imgFiles[j];
  } }
}

function MM_swapImage() { //v2.0
  var i,j=0,objStr,obj,swapArray=new Array,oldArray=document.MM_swapImgData;
  for (i=0; i < (MM_swapImage.arguments.length-2); i+=3) {
    objStr = MM_swapImage.arguments[(navigator.appName == 'Netscape')?i:i+1];
    if ((objStr.indexOf('document.layers[')==0 && document.layers==null) ||
        (objStr.indexOf('document.all[')   ==0 && document.all   ==null))
      objStr = 'document'+objStr.substring(objStr.lastIndexOf('.'),objStr.length);
    obj = eval(objStr);
    if (obj != null) {
      swapArray[j++] = obj;
      swapArray[j++] = (oldArray==null || oldArray[j-1]!=obj)?obj.src:oldArray[j];
      obj.src = MM_swapImage.arguments[i+2];
  } }
  document.MM_swapImgData = swapArray; //used for restore
}