//****************************************************************
//                       icHistory.js (_ic307.txt)
//
//             Copyright (c) 2006 Clifford L. Collins
//             All rights are Reserved
//
//	       Collins Software 
//	       7710 Janak Drive, Houston Texas
//
//----------------------------------------------------------------
//   No distribution/publication/use of this code is permitted
//****************************************************************  

var history = new ic$History();

//=====================================================================
//                            historyBack
//=====================================================================
function historyBack()
{
	history.back();
}
//=====================================================================
//                            historyForeward
//=====================================================================
function historyForeward()
{
	history.foreward();
}
//=====================================================================
//                           ic$HistoryWindow (Constructor)
//=====================================================================
function ic$HistoryWindow(x,y,level)
{
	this.x = parseFloat(x);
	this.y = parseFloat(y);
	this.level = parseInt(level);
	this.next = null;
	this.prev = null;
}
//=====================================================================
//                           ic$History (Constructor)
//=====================================================================
function ic$History()
{
   this.top   = null;
   this.bot   = null;
   this.cur   = null;
   this.count = 0;
   this.limit = 20;   // history depth
   this.noAdd = false;

//-------- Procedures --------

   this.add       = HISTORY$add; 
   this.back      = HISTORY$back;
   this.foreward  = HISTORY$foreward;
   this.draw      = HISTORY$draw;

   this.setButtons = HISTORY$setButtons;
   this.last       = HISTORY$last;
   this.first      = HISTORY$first;
}
//=====================================================================
//                           HISTORY$add
//=====================================================================
function HISTORY$add(x,y,level)
{

//---------------- add new window -------------

     if (this.noAdd) return;
    
//	alert(x + ' ' + y + ' ' + level);

	if (this.count < this.limit)    
	{
	  h = new ic$HistoryWindow(x,y,level)
	  this.cur = h; 

      if (this.top == null)
	  {
 	      this.top = h;
	      this.bot = h;
	      this.count = 1;
	  }
	  else
	  {
	      h.prev = this.bot;
	      this.bot.next = h;
	      this.bot = h;
	      this.count = this.count + 1;
	  }
	}

//---------------- reuse old window (remove from top) -------
	else
	{
	    h = this.top;
	    h.x = parseFloat(x);
	    h.y = parseFloat(y);
	    h.level = parseInt(level);

	    h.next.prev = null;  // move H out of list
	    this.top = h.next;

	    this.bot.next = h;
	    h.prev = this.bot;
	    h.next = null;
	    this.bot = h;
	    this.cur = h;
	}

    this.setButtons();	
}

//=====================================================================
//                           HISTORY$foreward
//=====================================================================
function HISTORY$setButtons()
{
   	obj = getObject('historyPrev');
	if (obj) obj.src = this.first();
	obj = getObject('historyNext');
	if (obj) obj.src = this.last();
}
//=====================================================================
//                           HISTORY$foreward
//=====================================================================
function HISTORY$draw()
{
    if (this.cur == null) return;
	this.noAdd = true;
 
    goLevel(this.cur.level);
    goXY(this.cur.x,this.cur.y);
    draw();
   
    if (window.parent) window.parent.moveTo(ID,this.cur.x,this.cur.y);

    this.noAdd = false;
    this.setButtons();	
    
}
//=====================================================================
//                           HISTORY$foreward
//=====================================================================
function HISTORY$foreward()
{
	if (this.cur == null) return null;
	if (this.cur.next == null) return null;
	this.cur = this.cur.next;
	this.draw();
}
//=====================================================================
//                           HISTORY$back
//=====================================================================
function HISTORY$back()
{
	if (this.cur == null) return null;
	if (this.cur.prev == null) return null;
	this.cur = this.cur.prev;
	this.draw();
}
//=====================================================================
//                           HISTORY$first
//=====================================================================
function HISTORY$first()
{
	if (this.cur == null) return "images/viewBackOff.gif";
	if (this.cur.prev == null) return "images/viewBackOff.gif";
	return "images/viewBackOn.gif";
}
//=====================================================================
//                           HISTORY$last
//=====================================================================
function HISTORY$last()
{
	if (this.cur == null) return "images/viewForewardOff.gif";
	if (this.cur.next == null) return "images/viewForewardOff.gif";
	return "images/viewForewardOn.gif";
}