pureconfig: a case class of a sealed trait by the boolean value

Main.scala

import com.typesafe.config.ConfigObject
import pureconfig._
import pureconfig.error.{CannotParse, ConfigReaderFailures}

sealed trait Enigma
object Enigma {
  case class Foo(value: Int) extends Enigma
  case object Bar extends Enigma
}

object Main extends App {

  implicit val enigmaReader: ConfigReader[Enigma] = ConfigReader.fromFunction[Enigma] {
    case configObj: ConfigObject =>
      val config = configObj.toConfig
      if (config.getBoolean("is-foo")) loadConfig[Enigma.Foo](config)
      else Right(Enigma.Bar)
    case _ =>
      Left(ConfigReaderFailures(CannotParse("eto ditch", None)))
  }
  
  /* application.conf:
    enigma1 {
      is-foo = true
      value = 1
    }

    enigma2 {
      is-foo = false
    }
   */

  println(loadConfig[Enigma]("enigma1")) // Right(Foo(1))
  println(loadConfig[Enigma]("enigma2")) // Right(Bar)

}