Name.scala

package mesosphere.servicenet.dsl

import scala.Ordered

import Ordering.Implicits._

/**
  * Names for network entities.
  *
  * The sort order for names is the intuitive one for DNS names: sort on dotted
  * subcomponents, starting from the back (might be revisited for network
  * interface names).
  *
  * There are length and content limitations to impose at some point in the
  * future. DNS names should contain only letters, digits and hyphens, and be
  * under 255 octets in total. Linux device names should probably come from the
  * same set of characters -- and must be much shorter.
  */
case class Name(components: Seq[String]) extends Ordered[Name] {
  def compare(other: Name) = Orderings.NameOrdering.compare(this, other)
}

object Name {
  def dotted(s: String): Seq[String] = s.split('.').reverse.toSeq

  def apply(s: String): Name = Name(dotted(s))

  implicit def String2Name(s: String): Name = Name(s)

  implicit def Name2String(n: Name): String =
    n.components.reverse.mkString(".")
}

/**
  * Sorts for datatypes related to network entity names.
  */
object Orderings {
  implicit val NameOrdering: Ordering[Name] =
    Ordering.by[Name, Seq[String]](_.components)

  implicit val StringOrdering: Ordering[String] =
    Ordering.by[String, Name](Name(_))

  implicit val ChangeOrdering: Ordering[Change] = Ordering.by {
    case Add(item)    => item.name()
    case Remove(name) => name
  }
}