slides = 4;
index = 0;

demoUris = ["http://www.analoganalytics.com/products/bigger_better_deals.html", "http://www.analoganalytics.com/demo/sdnn.html", "http://demo2.analoganalytics.net/offers", "http://demo.analoganalytics.net/placements/18/coupons/create", "http://demo2.analoganalytics.net/reports"]

$('left_arrow').observe('click', showPreviousSlide);
$('right_arrow').observe('click', showNextSlide);
Event.observe(window, 'load', showFirstSlide);

function showPreviousSlide(event) {
  if (index == 0 || index == 1) {
    newIndex = slides;
  } else {
    newIndex = index - 1;
  }

  if (index > 0) {
    $("slide_" + index).fade({ queue: "end" });
  }
  $("slide_" + newIndex).appear({ queue: "end" });
  $("demo_link").href = demoUris[newIndex - 1];

  index = newIndex;
  createCookie("slide", index, 300);
}

function showNextSlide(event) {
  if (index == slides) {
    newIndex = 1;
  } else {
    newIndex = index + 1;
  }

  if (index > 0) {
    $("slide_" + index).fade({ queue: "end" });
  }
  $("slide_" + newIndex).appear({ queue: "end" });
  $("demo_link").href = demoUris[newIndex - 1];

  index = newIndex;
  createCookie("slide", index, 300);
}

function showFirstSlide() {
  cookie = readCookie("slide");
  if (cookie != null) {
    index = Number(cookie);
  }
  showNextSlide();
}

function createCookie(name,value,days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime()+(days*24*60*60*1000));
    var expires = "; expires="+date.toGMTString();
  }
  else var expires = "";
  document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');
  for(var i=0;i < ca.length;i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1,c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }
  return null;
}