Reactive Scala Driver for MongoDB

import reactivemongo.bson.{
  BSONDocument, BSONDocumentReader, BSONDocumentWriter
}

object BSONMap {
  implicit def MapReader[V](implicit vr: BSONDocumentReader[V]): BSONDocumentReader[Map[String, V]] = new BSONDocumentReader[Map[String, V]] {
    def read(bson: BSONDocument): Map[String, V] = {
      val elements = bson.elements.map { tuple =>
        // assume that all values in the document are BSONDocuments
        tuple._1 -> vr.read(tuple._2.seeAsTry[BSONDocument].get)
      }
      elements.toMap
    }
  }

  implicit def MapWriter[V](implicit vw: BSONDocumentWriter[V]): BSONDocumentWriter[Map[String, V]] = new BSONDocumentWriter[Map[String, V]] {
    def write(map: Map[String, V]): BSONDocument = {
      val elements = map.toStream.map { tuple =>
        tuple._1 -> vw.write(tuple._2)
      }
      BSONDocument(elements)
    }
  }
}

import reactivemongo.bson.{ BSON, BSONDocument, BSONHandler }

case class Album(
  title: String,
  releaseYear: Int,
  hiddenTrack: Option[String],
  allMusicRating: Option[Double],
  tracks: List[String])

case class Artist(
  name: String,
  albums: List[Album])

implicit def artistHandler: BSONHandler[BSONDocument, Artist] = ???
implicit def mapHandler: BSONHandler[BSONDocument, Map[String, Artist]] = ???

def neilYoung: Artist = ???

val map = Map("artist1" -> neilYoung)
val docFromMap: BSONDocument = BSON.writeDocument(map)
val mapFromDoc: Map[String, Artist] = 
  BSON.readDocument[Map[String, Artist]](docFromMap)