var navArray = new Array();
var navPosition = 0;

var backArrow;
var forwardArrow;
var scrollBlock = false;

function navArrayUpdate (pos,typ,scrl)
{
	var position = pos;
	var type = typ;
	var scroll = scrl;
	navArray = navArray.slice (0,navPosition+1);
	var pair = new Array (position,type);
	navArray.push (pair);
	navPosition = navArray.length-1;
	if (navPosition!=0)
	{
		navArray[navPosition-1].push(scroll);
	}
	updateArrows ();
}

function updateArrows ()
{
	backArrow = $('.arrowLeft');
	forwardArrow = $('.arrowRight');
	if (navPosition == 0)
	{
		backArrow.attr('src','pics/backGrey.png');
		backArrow.removeClass ('arrowActive');
	}
	else
	{
		backArrow.attr('src','pics/backBlue.png');
		backArrow.addClass ('arrowActive');
	}
	if (navPosition == (navArray.length)-1)
	{
		forwardArrow.attr('src','pics/forwardGrey.png');
		forwardArrow.removeClass ('arrowActive');
	}
	else
	{
		forwardArrow.attr('src','pics/forwardBlue.png');
		forwardArrow.addClass ('arrowActive');
	}
}

function navigate (arw)
{
	var arrow = $(arw);
	if (arrow.hasClass('arrowActive') && arrow.hasClass('arrowLeft'))
	{
		navigateDraw (navArray[navPosition-1]);
		navPosition = navPosition - 1;
	}
	if (arrow.hasClass('arrowActive') && arrow.hasClass('arrowRight'))
	{
		navigateDraw (navArray[navPosition+1]);
		navPosition = navPosition + 1;
	}
	updateArrows ();
}

function navigateDraw (pr)
{
	var pair = pr;
	var position = pair[0];
	var type = pair[1];
	var scroll = pair[2];
	var treeArray = outerTreeArray;
	var postsHolder = pa.find('.posts');
	postsHolder.empty();
	var selectedPost = treeArray [position];

	while (selectedPost['parentID'] != null)
	{
		var parentPosition = selectedPost['parentPosition'];
		selectedPost = treeArray [parentPosition];
		post = makePost(selectedPost, parentPosition,0);	
		
		postsHolder.prepend(post);
	}
	
	var selectedPost = treeArray[position];		
	post = makePost (selectedPost, position, 0);		
	postsHolder.append(post);
	
	scrollBlock = true;
	
	if (type == 'chain')
	{
		drawChain (position);
	}
	if (type == 'replies')
	{
		drawReplies (position,false);
	}
	if (type== 'replyBox')
	{
		id = post.attr('postid');
		drawReplyPost(position,id);
	}
	
	scrollBlock = false;
	$('html, body').animate({
		scrollTop: scroll
	}, 0);
}