// Declare the number of menus
// N.B. Add menu IDs and adjust
// widths of divs in stylesheet:
// visibility-HorizontalMenus.css
///////////////////////////////////////

// Global number for total menus:
///////////////////////////////////////
var totalmenus = 5;

// Global number for counting the tab
// sequence
///////////////////////////////////////
var tabcount = 0;

// Global string for menu output:
///////////////////////////////////////
var menutxt = '';

// Global array for menu data:
///////////////////////////////////////
var menu = new makeArray(totalmenus);

// Custom array constructor,
// indexed from 1:
///////////////////////////////////////
function makeArray(n){
  this.size = n;
  for(i=1; i<=n; i++){
    this[i] = 0;
  }
  return(this);
}

// Menu group constructor:
///////////////////////////////////////
function menuObject(n,MenuTitle,MenuURL){
  this.size =       n;
  this.MenuTitle =  MenuTitle;
  this.MenuURL =    MenuURL;
  this.Bullet =     new makeArray(n);
}

// Menu item constructor:
///////////////////////////////////////
function bulletObject(BulletTitle,BulletURL){
  this.BulletTitle =  BulletTitle;
  this.BulletURL =    BulletURL;
}

// Define menus. Add new items by
// increasing menu bullets argument
// and adding a new indexed bullet
// object to the end of the list.
//
// Menu arguments:
// 1 = No. of bullets
// 2 = Menu title
// 3 = Menu URL

// Bullet arguments:
// 1 = Bullet title
// 2 = Bullet URL
///////////////////////////////////////

// First menu
///////////////////////////////////////
menu[1] = new menuObject(5,'Introduction','#');
menu[1].Bullet[1] = new bulletObject('Overview',        'javascript:showfile(\'/intro.html\');');
menu[1].Bullet[2] = new bulletObject('Progress',        'javascript:showfile(\'/progress.html\');');
menu[1].Bullet[3] = new bulletObject('Bibliography',    'javascript:showfile(\'/bibliography.html\');');
menu[1].Bullet[4] = new bulletObject('Markup',          'javascript:showfile(\'/markup.html\');');
menu[1].Bullet[5] = new bulletObject('Acknowledgements','javascript:showfile(\'/acknowledgements.html\');');

// Second menu
///////////////////////////////////////
menu[2] = new menuObject(6,'Literary Editions','#');
menu[2].Bullet[1] = new bulletObject('Manuscript A','javascript:showedition(\'a\', \'literary\');');
menu[2].Bullet[2] = new bulletObject('Manuscript B','javascript:showedition(\'b\', \'literary\');');
menu[2].Bullet[3] = new bulletObject('Manuscript C','javascript:showedition(\'c\', \'literary\');');
menu[2].Bullet[4] = new bulletObject('Manuscript D','javascript:showedition(\'d\', \'literary\');');
menu[2].Bullet[5] = new bulletObject('Manuscript E','javascript:showedition(\'e\', \'literary\');');
menu[2].Bullet[6] = new bulletObject('Manuscript H','javascript:showedition(\'h\', \'literary\');');

// Third menu
///////////////////////////////////////
menu[3] = new menuObject(2,'Philological Editions','#');
menu[3].Bullet[1] = new bulletObject('Manuscript A','javascript:showedition(\'a\', \'philological\');');
menu[3].Bullet[2] = new bulletObject('Manuscript B','javascript:showedition(\'b\', \'philological\');');

// Fourth menu
///////////////////////////////////////
menu[4] = new menuObject(1,'Reconstructions','#');
menu[4].Bullet[1] = new bulletObject('The Common Stock','javascript:showedition(\'common\', \'literary\', true);');

// Fifth menu
///////////////////////////////////////
menu[5] = new menuObject(5,'Descriptions');
menu[5].Bullet[1] = new bulletObject('Manuscript A','javascript:showfile(\'/a/a-descm.html\');');
menu[5].Bullet[2] = new bulletObject('Manuscript B','javascript:showfile(\'/b/b-descm.html\');');
menu[5].Bullet[3] = new bulletObject('Manuscript C','javascript:showfile(\'/c/c-descm.html\');');
menu[5].Bullet[4] = new bulletObject('Manuscript D','javascript:showfile(\'/d/d-descm.html\');');
menu[5].Bullet[5] = new bulletObject('Manuscript E','javascript:showfile(\'/e/e-descm.html\');');

// Compile the static menu headings:
///////////////////////////////////////
menutxt += '<div id="LinkBar">\n';
for(i=1;i<=totalmenus;i++){
    // Increment the tabindex counter for every link
    tabcount++;
    menutxt += '\t<div id="Link' + i + '">';
    menutxt += '<a href="' + menu[i].MenuURL + '"';

    // Add an explicit tab sequence
    menutxt += ' tabindex="' + tabcount + '"';

    // Only compile the event handlers if able to handle them
    if(document.getElementById){// DOM1 compliant
      menutxt += ' onmouseover="menuOver(\'' + i + '\'); return true;"';
      // To activate via tab navigation
      menutxt += ' onfocus="menuOver(\'Menu' + i + '\'); return true;"';
      menutxt += ' onmouseout="menuOut(\'Menu' + i + '\'); return true;"';
      // To de-activate when tab focus is lost
      menutxt += ' onblur="menuOut(\'Menu' + i + '\'); return true;"';

      // Increment the tabindex to allow for the bullets
      tabcount += menu[i].Bullet.size;
    }
    menutxt += '>' + menu[i].MenuTitle + '</a>';
    menutxt += '<\/div>\n';
  }
menutxt += '<\/div>\n';

// If DOM1 compliant, add the
// drop-down menus:
///////////////////////////////////////
if(document.getElementById){// DOM1 compliant
  // Reset the tab counter
  tabcount = 0;
  menutxt += '<div id="MenuBar">\n';
  for(i=1;i<=totalmenus;i++){
    // Increment the tab counter
    tabcount++;
    menutxt += '<div id="Menu' + i + '">';
    // Build the bullet list
    menutxt += '<ul>\n\t';
    for(j=1;j<=menu[i].size;j++){
      // Increment the tab couter
      tabcount++
      menutxt += '<li><a href="' + menu[i].Bullet[j].BulletURL + '"';
      menutxt += ' onmouseover="stayOpen(\'' + i + '\'); return true;"';
      menutxt += ' onfocus="stayOpen(\'' + i + '\'); return true;"';
      menutxt += ' onmouseout="menuOut(\'Menu' + i + '\'); return true;"';
      menutxt += ' onblur="menuOut(\'Menu' + i + '\'); return true;"';
      // Add an explicit tab sequence
      menutxt += ' tabindex="' + tabcount + '"';
      menutxt += '>' + menu[i].Bullet[j].BulletTitle;
      menutxt += '<\/a><\/li>\n\t';
    }
    menutxt += '<\/ul>\n<\/div>\n';
  }
  menutxt += '<\/div>\n';
}

// Global menu element handle:
///////////////////////////////////////
var LiveMenu = null;

// Global menu timeout handle:
///////////////////////////////////////
var Timeout_ID = null;

function leftPosition(oLink)
{
  var posX = 0;
  if (oLink.offsetParent)
  {
     for( posX = 0; oLink.offsetParent; oLink = oLink.offsetParent )
     {
       posX += oLink.offsetLeft;
     }
  }
  else
  {
    posX = oLink.x;
  }
  return posX + "px";
}

// Opens or keeps open a given menu
// and shuts any previous menu:
///////////////////////////////////////
function menuOver(ID){
  var MenuID = 'Menu' + ID;
  var LinkID = 'Link' + ID;
  // If DOM1 supported and element exists ...
  if((document.getElementById)&&(document.getElementById(MenuID)!=null))
  {
    // If this menu is already open ...
    if(LiveMenu==document.getElementById(MenuID)){
      // Do not close it
      clearTimeout(Timeout_ID);
    }
    // Another might still be open ...
    else
    {
      // If another menu is open ...
      if(LiveMenu!=null)
      {
        // Do not wait, shut it now
        clearTimeout(Timeout_ID);
        hideNow();
      }
    }
    // This is the new 'live' menu, make it visible
    LiveMenu = document.getElementById(MenuID);
    var LiveLink = document.getElementById(LinkID);
    // LiveMenu.style.visibility is
    // initially empty in IE5 until
    // it is assigned by these
    // functions, so must check that
    // it's not null before proceeding...
    if((LiveMenu.style)&&(LiveMenu.style.visibility!=null))
    {
      LiveMenu.style.left = leftPosition(LiveLink);
      LiveMenu.style.visibility = 'visible';
    }
  }
}

// Stops menu links from opening menu
// onmouseover when shut to
// workaround mouse events which are
// not hidden by z-index in Opera 4!
///////////////////////////////////////
function stayOpen(ID)
{
  // If menuOver has not been called or the menu is hidden, do nothing
  if((LiveMenu==null)||((LiveMenu.style)&&(LiveMenu.style.visibility)&&(LiveMenu.style.visibility=='hidden')))return;
  else menuOver(ID);
}

// Shuts a given menu in 250
// milliseconds, unless timeout is
// cleared by menuOver()
///////////////////////////////////////
function menuOut(MenuID)
{
  // If DOM1 supported and a menu is open ...
  if((document.getElementById)&&(document.getElementById(MenuID)!=null)){
    // Get the current live menu
    LiveMenu = document.getElementById(MenuID);
    // Prepare to shut it in 250 milliseconds
    Timeout_ID = window.setTimeout('hideNow();',250);
  }
}

// Called by menu handlers to shut
// previous menu immediately
///////////////////////////////////////
function hideNow(){
  if((LiveMenu.style)&&(LiveMenu.style.visibility)){
    LiveMenu.style.visibility = 'hidden';
  }
}