Allow person to be correspondent, concerning or both

modules/common/src/main/scala/docspell/common/PersonUse.scala

@@ -0,0 +1,50 @@
+package docspell.common
+
+import cats.data.NonEmptyList
+
+import io.circe.Decoder
+import io.circe.Encoder
+
+sealed trait PersonUse { self: Product =>
+
+  final def name: String =
+    self.productPrefix.toLowerCase()
+}
+
+object PersonUse {
+
+  case object Correspondent extends PersonUse
+  case object Concerning    extends PersonUse
+  case object Both          extends PersonUse
+
+  def concerning: PersonUse    = Concerning
+  def correspondent: PersonUse = Correspondent
+  def both: PersonUse          = Both
+
+  val concerningAndBoth: NonEmptyList[PersonUse] =
+    NonEmptyList.of(Concerning, Both)
+
+  val correspondentAndBoth: NonEmptyList[PersonUse] =
+    NonEmptyList.of(Correspondent, Both)
+
+  def fromString(str: String): Either[String, PersonUse] =
+    str.toLowerCase() match {
+      case "correspondent" =>
+        Right(Correspondent)
+      case "concerning" =>
+        Right(Concerning)
+      case "both" =>
+        Right(Both)
+      case _ =>
+        Left(s"Unknown person-use: $str")
+    }
+
+  def unsafeFromString(str: String): PersonUse =
+    fromString(str).fold(sys.error, identity)
+
+  implicit val jsonDecoder: Decoder[PersonUse] =
+    Decoder.decodeString.emap(fromString)
+
+  implicit val jsonEncoder: Encoder[PersonUse] =
+    Encoder.encodeString.contramap(_.name)
+}