var current_gift = "gift01";

function zeroPad(num) {
  return (num > 9) ? num : '0' + num;
}

function getNextGift() {  
  next_index = parseInt(current_gift.substring(
    current_gift.length - 2), 10) + 1;
  
  if (next_index > 20) { next_index = 1; }
  
  return('#gift' + zeroPad(next_index));
}

function getPreviousGift() {
  next_index = parseInt(current_gift.substring(
    current_gift.length - 2), 10) - 1;

  if (next_index <= 0) { next_index = 20; }

  return('#gift' + zeroPad(next_index));
}

function selectGift(gift) {
  current_gift = gift;
	jQuery('#GiftsWrapper').scrollTo(current_gift, 700);
	jQuery('li.active').removeClass('active');
	jQuery(current_gift + 'nav').parents("li").each(function() { 
    jQuery(this).addClass("active");
  });
}

jQuery(document).ready(function() {
	jQuery('a.gift').click(function () {
	  selectGift(jQuery(this).attr('href'));
		return false;
	});
	
	jQuery('#previousGift').click(function () {
	  selectGift(getPreviousGift())
	  return false;
	});

	jQuery('#nextGift').click(function () {
    selectGift(getNextGift());
	  return false;
	});
});