// variables for making the slides transition
var currSlide = 1;
var prevSlide = 0;
var nextSlide = 1;
var rotateDelay = 7000;
var delayCount = 0;
var numSlides = 0;

// store the links to the proper slides in this array
// spot 0 is slide 1, 1 is 2, etc...
// leave a slide as an empty string if you want it to
// not go anywhere
var links = new Array(5);
links[0] = "http://ppld.org/blogs/teen/?cat=13";	// slide 1
links[1] = "http://school.discoveryeducation.com/sciencefaircentral/";	// slide 2
links[2] = "http://www.teencentral.net/";	// slide 3
links[3] = "http://www.pbs.org/wgbh/nova/lostempires/trebuchet/";	// slide 4
links[4] = "http://online.culturegrams.com/index.php";	// slide 5
links[5] = "http://ezproxy.ppld.org:2048/login?url=http://main.ppld.co.brainfuse.com";	// slide 6
links[6] = "http://www.workscited4u.com/";	// slide 7
links[7] = "http://ppld.org/Blogs/Teen/";	// slide 8
links[8] = "#9";	// slide 9
links[9] = "#10";	// slide 10
links[10] = "#11";	// slide 11
links[11] = "#12";	// slide 12
links[12] = "#13";	// slide 13
links[13] = "#14";	// slide 14
links[14] = "#15";	// slide 15


// starts the slides initially
function createSlides()
{
	//makes the first slide visible
	$("#slide_1").css("z-index", "5");
	
	// counts the number of slides
	numSlides = $("#slides").children().length;
	
	//hides the rest of the slides
	for(i=2; i<=numSlides; i++)
	{
		$("#slide_"+i).css("z-index", "3");
		$("#slide_"+i).fadeTo("0", 0.0);
	}
	
	// unhides needed buttons
	for(i=1; i<=numSlides; i++)
	{
		$("#button_"+i).css("display", "inline");
	}
	
	setLink(1);
	setTimeout("rotateSlide()", rotateDelay);
}

// makes the slideshow go to a specific slide
function gotoSlide(slide_num)
{
	delayCount = 1;
	nextSlide = slide_num;
	fadeInSlide(slide_num);
}

//changes the links to show the appropriate link highlighted
function setLink(slide_num)
{
	if(prevSlide != 0)
	{
		$("#button_"+prevSlide).attr("src", "assets/buttons/button"+prevSlide+".png");
	}
		
	$("#button_"+currSlide).attr("src", "assets/buttons/button"+currSlide+"a.png");
	
	setSlideLink(slide_num);
}

// changes the slide to the next slide on a timer
function rotateSlide()
{
	if(delayCount == 0)
	{
		nextSlide++;
		if(nextSlide > numSlides)
		{
			nextSlide = 1;
		}
		
		fadeInSlide(nextSlide);
	}
	else
	{
		delayCount = 0;
	}
	setTimeout("rotateSlide()", rotateDelay);
}

// fades the next slide in.
function fadeInSlide(slide_num)
{
	if(slide_num != currSlide)
	{
		prevSlide = currSlide;
		currSlide = slide_num;
		
		// switches the current slide and next slide
		$("#slide_"+prevSlide).css("z-index", "3");
		$("#slide_"+currSlide).css("z-index", "5");
		
		// fades them together
		$("#slide_"+currSlide).fadeTo(500, 1.0);
		$("#slide_"+prevSlide).fadeTo(1000, 0.0);
	
		setLink(slide_num);
	}
}

// sets the slide link so that you can direct to somewhere else
function setSlideLink(slide_num)
{
	if(slide_num - 1 > (numSlides - 1) || slide_num - 1 < 0 || links[slide_num] == "")
	{
		$("#slide_linker").attr("href", "#");
		$("#slide_linker").css("cursor", "default");
	}
	else
	{
		$("#slide_linker").attr("href", links[slide_num-1]);
		$("#slide_linker").css("cursor", "pointer");
	}
}