function isPrev(current, index, list) {
  return (current - 1 + list.length) % list.length === index;
}

function isNext(current, index, list) {
  return (current + 1 + list.length) % list.length === index;
}

function getImageClass(prefix, current, index, list) {
  var arr = [prefix + '-swiper__image', prefix + '-class-image'];

  if (isPrev(current, index, list)) {
    arr.push(prefix + '-class-prev-image')
  }

  if (isNext(current, index, list)) {
    arr.push(prefix + '-class-next-image')
  }

  return arr.join(' ');
}

module.exports.isPrev = isPrev;
module.exports.isNext = isNext;
module.exports.getImageClass = getImageClass;