gooooooogle.scala

gooooooogle.scala

case class Paginator(previous: Option[Int], selections: List[Int], current: Int, next: Option[Int])

def pagination(current: Int, total: Int, window: Int = 10): Paginator = {
  val prev =
    if(current == 1) None
    else Some(current -1)

  val next =
    if(current == total) None
    else Some(current + 1)

  val delta = (window - 1) / 2
  val (start, end) =
    if(current + delta <= total) {
      if(current - delta >= 1) (current - delta, current + delta)
      else (1, window + 1)
    } else (total - window, total)

  val sels = (start to end).toList

  Paginator(prev, sels, current, next)
}

def renderP(paginator: Paginator): String = {
  import paginator._
  val p = previous.map(_ => "<").getOrElse(" ")
  val s = selections.map(s => if(s == current) s"*$s*" else s" $s " ).mkString("")
  val n = next.map(_ => ">").getOrElse("")
  s"$p $s $n"
}

List(
  pagination( 1, 12),
  pagination( 6, 12),
  pagination( 7, 12),
  pagination( 8, 12),
  pagination(11, 12),
  pagination(12, 12)
).map(renderP).mkString(System.lineSeparator)