// change this to where you upload the images to your site
imgdir = "towers/";

// PreLoad all the images
function preload() 
{
  this.length = preload.arguments.length;
  for (var i = 0; i < this.length; i++) 
		{
    this[i] = new Image();
    this[i].src = imgdir + preload.arguments[i];
  }
}

//var pics = new preload("towers/disk1.gif", "towers/disk2.gif", "towers/disk3.gif", "towers/disk4.gif", "towers/disk5.gif", "towers/disk6.gif", "towers/disk7.gif", "towers/pole.gif", "towers/disk1h.gif","towers/disk2h.gif", "towers/disk3h.gif", "towers/disk4h.gif", "towers/disk5h.gif", "towers/disk6h.gif", "towers/disk7h.gif");

var pics = new preload("disk1.gif", "disk2.gif", "disk3.gif", "disk4.gif", "disk5.gif", "disk6.gif", "disk7.gif", "pole.gif", "disk1h.gif", "disk2h.gif", "disk3h.gif", "disk4h.gif", "disk5h.gif", "disk6h.gif", "disk7h.gif");


var selectedr = null;
var selectedc = null;
var maxposts = 3;
var maxdisks = 7;
var all_posts = 3;
var startpost = 1;
var endpost = (startpost-1 < 0 ? maxposts-1 : startpost-1);
var disks = 7;
var imgwidth = 160;
var imgheight = 14;
var game_is_over = false;
var show_messages = false;
var board = new Array(maxposts);
board[0] = new Array(maxdisks + 1);
board[1] = new Array(maxdisks + 1);
board[2] = new Array(maxdisks + 1);


function initboard(startpost, disks) 
{
  var len = board[0].length;
  selectedc = null;
  selectedr = null;
  game_is_over = false;
  endpost = (startpost-1 < 0 ? maxposts-1 : startpost-1);

  for (i = 0; i < len; i++) 
		{
    board[0][i] = 0;
    board[1][i] = 0;
    board[2][i] = 0;
  }
  for (i = len-disks, j = 0; i < len; i++, j++) 
  {
    board[startpost][i] = len - j - 1;
  }
}


function drawboard() 
{
  document.writeln("<p>");
  document.writeln("<table cellspacing=0 cellpadding=0 border=0 align=center>");
  document.writeln("<tr>");
  for (j = 0; j < board.length; j++) 
  {
    document.write("<td>");
    document.write("<a href='javascript:clicked("+0+","+j+")'><img src='" + imgdir + "posttop1.gif' border=0></a><br>");
    for (i=0; i< board[0].length; i++) 
    {
      document.write("<a href='javascript:clicked("+i+","+j+")'>");
      document.write("<img src='" + imgdir + getName(board[j][i]) + "' name='pos"+ j + i + "' border=0><br>");
      document.write("</a>");
    }
    document.writeln("</td>");
  }
  document.writeln("</tr></table>");
}


function drawall() 
{
  for (j=0; j<board.length; j++) 
  {
    for (i=0; i<board[j].length; i++) 
    {
      draw(j,i, getName( board[j][i]));
    }
  }
  message("You may begin! Select a piece to move.");
}

function restart(start) 
{
  startpost = start;
  disks = document.f1.disc.options[document.f1.disc.selectedIndex].text;
  initboard(startpost,disks);
  drawall();
  theAnim = new Animation();
}

function getName( num ) 
{
  if (num == 0) return "post1.gif";
  return "disk" + num + ".gif";
}

function message(str, force) 
{
  if (force || !game_is_over && !show_messages)
    document.f1.message.value = str;
}

function messageadd(str) 
{
  if (!game_is_over)
    document.f1.message.value = document.f1.message.value + "\n" + str;
}

function isempty(num) 
{
  for (i = 0; i < board[num].length; i++) 
		{
    if ( board[num][i] != 0) return false;
  }
  return true;
}

function topmost(num) 
{
  for (i = 0; i < board[num].length; i++) 
		{
    if (board[num][i] != 0) return  i;
  }
  return -1;
}

function ispost(i,j) 
{
  return (board[j][i] == 0);
}

function istopdisk(i,j) 
{
  return (board[j][i-1] == 0);
}

function draw(x,y,name) 
{
  document.images["pos"+x+""+y].src = imgdir + name;
}

function animate(x,y,name) 
{
  theAnim.addFrame( "pos"+x+""+y, imgdir + name);
}

function clicked(i,j) 
{
  document.f1.message.focus(); // get rid of annoying outline in MSIE
  document.f1.message.blur();

  if (game_is_over)  restart(startpost = endpost);
  if (!isselection() && ispost(i,j)) 
		{ 
		  message("Select a piece to move.");
				return; 
		}
  if (!ispost(i,j)) 
		{ 
		  toggle(j); 
				return; 
		};
  if (ispost(i,j) && selectedc == j) 
		{ 
		  message("Move the piece to a different post.");
				return;
		}
  if (!legalmove(j)) 
		{ 
		  message("That is not a legal move. Try again."); 
				return;
		}
  move(j); return;
}

function legalmove(j) 
{
  if (isempty(j)) return true;
  return (board[j][topmost(j)] < board[selectedc][selectedr]);
}

function isselection() 
{
  return selectedc != null;
}

function toggle( num ) 
{
  var toppos = topmost(num);
  if (selectedc == num && selectedr == toppos) 
		{
    selectedc = null; selectedr = null;
    animate(num,toppos,"disk" + board[num][toppos] + ".gif");
    message("Select a piece to move.");
    return;
  }
  if (isselection()) 
		{
    animate(selectedc,selectedr,"disk" + board[selectedc][selectedr] + ".gif");
  }
  selectedc = num; selectedr = toppos;
  animate(num,toppos,"disk" + board[num][toppos] + "h.gif");
  message("Click on the post to which you want to move the disk.");
}

function move( num ) 
{
  var toppos = (!isempty(num) ? topmost(num) : board[num].length);
  board[num][toppos-1] = board[selectedc][selectedr];
  board[selectedc][selectedr] = 0;
  animate(selectedc,selectedr,"post1.gif");
  animate(num,toppos-1,"disk" + board[num][toppos-1] + ".gif");
  selectedc = null; selectedr = null;
  message("Select a piece to move.");
  game_over();
}

function hanoi(no_of_disks, start_post, goal_post) 
{
  if (no_of_disks > 0) 
		{
    var free_post = all_posts - start_post - goal_post;
    hanoi (no_of_disks - 1, start_post, free_post);
    show_messages = true;
    toggle(start_post);
    move(goal_post);
    show_messages = false;
    hanoi (no_of_disks - 1 , free_post, goal_post);
    game_over(true);
  }
}

function game_over(forceMsg) 
{
  var filledpost = null;
  var val = 0;
  for (k = 0; k < board.length; k++)  
		{
    val += ( isempty(k) ? 1 : 0 );
    if (!isempty(k)) filledpost = k;
  }

  if (val == 2 && isempty(startpost)) 
  {
    message("You won!", forceMsg);
    game_is_over = true;
    endpost = filledpost;
	stopTimer();
	document.f1.submit();
  }
  return game_is_over;
}

//
// Animation functions
//

function Animation() 
{
  this.imageNum = new Array();  // Array of indicies document.images to be changed
  this.imageSrc = new Array();  // Array of new srcs for imageNum array
  this.frameIndex = 0;          // the frame to play next
  this.alreadyPlaying = false;  // semaphore to ensure we play smoothly

  this.getFrameCount = getframecount;   // the total numebr of frame so far
  this.moreFrames = moreframes;         // tells us if there are more frames to play
  this.addFrame = addframe;             // add a frame to the animation
  this.drawNextFrame = drawnextframe;   // draws the next frame
  this.startAnimation = startanimation; // start the animation if necessary
}

function getframecount() 
{  
  return this.imageNum.length; 
}

function moreframes() 
{  
  return this.frameIndex < this.getFrameCount(); 
}

function startanimation() 
{
  if (!this.alreadyPlaying) 
		{
    theAnim.alreadyPlaying = true;
    setTimeout('theAnim.drawNextFrame()',5);
  }
}

function addframe(num, src) 
{
  var theIndex = theAnim.imageNum.length;
  theAnim.imageSrc[theIndex] = src;
  theAnim.imageNum[theIndex] = num;
  theAnim.startAnimation();
}

function drawnextframe() 
{
  if (theAnim.moreFrames()) 
		{
    document.images[ theAnim.imageNum[theAnim.frameIndex] ].src = theAnim.imageSrc[theAnim.frameIndex];
    theAnim.frameIndex++;
    setTimeout('theAnim.drawNextFrame()', 300);
  } 
		else 
		{
    theAnim.alreadyPlaying = false;
  }
}


var t,tt,ttt
tt = 0
ttt=0

function timer()
{
  tt++
  document.f1.time.value = tt
  ttt = setTimeout("timer()",1000) 
}

function startTimer()
{
  clearTimeout(ttt)
  timer() 
}

function stopTimer()
{
   clearTimeout(ttt)
   tt = -1
}