// *** submenu position *******************************************************
// Two positions are available for now. New positions can be easily added.
var WM_BOTTOM = "bottom";
var WM_RIGHT = "right";
// Margin values in pixels. Allows for submenu position to be fine-tuned.
var MARGIN_BOTTOM = 1;
var MARGIN_RIGHT = 1;
// *** item activation ********************************************************
// One set of global values is enough, 
// no one can navigate more than one menu at the time.
// There can be only one active item at the time on the whole page.
var currentItem = null;
// There is only one way to reach a submenu. 
// The trail to that submenu is kept in this array.
// Every time an item is activated trail has to be reset. 
// All submenus after the current level removed and the current one added.
var menuTrail = new Array();
// This is needed when switching from one menu to another with two different
// styles, otherwise last element gets styleOff from the other menu.
var currentStyleOff = null;
// This function activates an item. 
// An item is active when mouse is over that item.
// Parameters:
// - item  . . . . . . . item to be activated
// - level . . . . . . . level of the submenu
// - styleOn . . . . . . style class name when item is active
// - styleOff. . . . . . style class name when item is not active
// - submenuId . . . . . id of the submenu that is to be attached to this item, pass null if no submenu
// - submenuPosition . . position of the submenu, ex: WM_RIGHT or WM_BOTTOM, pass null if no submenu
function wmItemOn(item, level, styleOn, styleOff, submenuId, submenuPosition) {
  debug("level:" + level + ", styleOn:" + styleOn + ", styleOff:" + styleOff + ", submenu:" + submenuId + "/" + submenuPosition);
  // assign timer off function to the item - makes html code cleaner
  if (item.onmouseout == null) {
    item.onmouseout = startOffTimer;
  }
  // stop timer on entry
  stopOffTimer();
  // turn off previous item 
  if (currentItem != null) {
    if (styleOff != currentStyleOff && currentStyleOff != null) {
      currentItem.className = currentStyleOff;
    } else {
      currentItem.className = styleOff;
    }
  }
  // make this item new current item
  currentItem = item;
  item.className = styleOn;
  currentStyleOff = styleOff;
  if (submenuId != null) {
    // take care of attached submenu
    hide(level);
    var menu = document.getElementById(submenuId);
    // item dimensions: item.offsetHeight, item.offsetWidth
    if (submenuPosition == WM_BOTTOM) {
      menu.style.top = findOffsetTop(item) + item.offsetHeight + MARGIN_BOTTOM;
      menu.style.left = findOffsetLeft(item);
    }
    if (submenuPosition == WM_RIGHT) {
      menu.style.top = findOffsetTop(item);
      menu.style.left = findOffsetLeft(item) + item.offsetWidth + MARGIN_RIGHT;
    }
    menu.style.visibility = "visible";
    menuTrail[level] = menu;
  } else {
    // item has no submenu attached, update the menuTrail
    
    hide(level);
  }
}
// Hide all submenus after the level passed in, inclusive.
function hide(level) {
  for (var i = level; i < menuTrail.length; i++) {
    menuTrail[i].style.visibility = "hidden";
  }
}
// *** timer ******************************************************************
// Timer is needed to turn off all the items and submenus, 
// once mouse moves away from the menu.
var timerID = null;
var timerOn = false;
var timecount = 250;
function startOffTimer() {
  if (timerOn == false) {
    timerID = setTimeout("offAll()", timecount);
    timerOn = true;
  }
}
function stopOffTimer() {
  if (timerOn) {
    clearTimeout(timerID);
    timerID = null;
    timerOn = false;
  }
}
// Hide all submenus and turn current item off.
function offAll() {
  hide(0);
  
  if (currentStyleOff != null) {
    currentItem.className = currentStyleOff;
  }
 
  debug("All off by timer.");
}
// *** debug ******************************************************************
// Print text to the debug element. If the element that debugId is pointing to 
// is not found on the page, it does nothing.
var debugId = "wmDebug";
function debug(text) {
  var debug = document.getElementById(debugId);
  if (debug != null) {
     debug.innerHTML = "&raquo; " + text + "<br>" + debug.innerHTML;
  }
}
// *** position ***************************************************************
// Utility code to calculate element position.
// Find total left offset.
function findOffsetLeft(obj){
  var curleft = 0;
  if (obj.offsetParent){
    while (obj.offsetParent){
      curleft += obj.offsetLeft;
      obj = obj.offsetParent;
    }
  } else if (obj.x) {
    curleft += obj.x;
  }
  return curleft;
}
// Find total top offset.
function findOffsetTop(obj){
  var curtop = 0;
  if (obj.offsetParent)    {
    while (obj.offsetParent){
      curtop += obj.offsetTop;
      obj = obj.offsetParent;
    }
  }else if (obj.y){
    curtop += obj.y;
  }
  return curtop;
}