pureconfig ConfigReader for parsing TimeUnit values

ConfigReaders.scala

import pureconfig.{ConfigReader, ConvertHelpers}

import scala.concurrent.duration.TimeUnit

trait ConfigReaders {
  import ConvertHelpers._

  implicit val dayOfWeekReader: ConfigReader[TimeUnit] =
    ConfigReader.fromString[TimeUnit](catchReadError(s => TimeUnitConverter.timeUnit(s)))
}

// Code extracted from https://github.com/pureconfig/pureconfig/blob/master/core/src/main/scala/pureconfig/DurationConvert.scala
object TimeUnitConverter {

  import concurrent.duration._

  private[this] val timeUnitLabels = List(
    DAYS -> "d day",
    HOURS -> "h hour",
    MINUTES -> "min minute",
    SECONDS -> "s sec second",
    MILLISECONDS -> "ms milli millisecond",
    MICROSECONDS -> "µs micro microsecond",
    NANOSECONDS -> "ns nano nanosecond")

  private[this] def words(s: String): List[String] = (s.trim split "\\s+").toList

  private[this] def expandLabels(labels: String): List[String] = {
    val hd :: rest = words(labels)
    hd :: rest.flatMap(s => List(s, s + "s"))
  }

  val timeUnit: Map[String, TimeUnit] =
    timeUnitLabels.flatMap { case (unit, names) => expandLabels(names) map (_ -> unit) }.toMap
}