SprayBsonSupport.scala

import spray.json._
import reactivemongo.bson._
import scala.language.implicitConversions

trait BSONDocumentFormat[T] extends BSONDocumentReader[T] with BSONDocumentWriter[T]

object SprayBson {

  implicit object BSONObjectIDJsonFormat extends JsonFormat[BSONObjectID] {
    def write(id: BSONObjectID) = JsString(id.toString)
    def read(value: JsValue) = value match {
      case JsString(x) => BSONObjectID(x)
      case x => deserializationError("Expected BSONObjectID as JsString, but got " + x)
    }
  }

  implicit def jsObjectToBsonDocument(json: JsObject) = BSONDocument(json.fields.toList.map(t ⇒ (t._1, t._2:BSONValue)))
  implicit def bsonDocumentToJsObject(bson: BSONDocument) = JsObject(bson.elements.toList.map(t ⇒ (t._1, t._2:JsValue)))

  implicit def jsValueToBsonValue(jsValue: JsValue): BSONValue = jsValue match {
    case JsString(value) ⇒ BSONString(value)
    case JsNumber(num) ⇒
      if (num.isValidInt) BSONInteger(num.intValue)
      else if (num.isValidLong) BSONLong(num.longValue)
      else BSONDouble(num.doubleValue)
    case JsFalse          ⇒ BSONBoolean(false)
    case JsTrue           ⇒ BSONBoolean(true)
    case JsNull           ⇒ BSONNull
    case JsArray(elems)   ⇒ BSONArray(elems.map(t ⇒ t:BSONValue))
    case obj: JsObject    ⇒ obj:BSONDocument
  }

  implicit def bsonValueToJsValue(bson: BSONValue): JsValue = bson match {
    case BSONString(value)  ⇒ JsString(value)
    case BSONDouble(value)  ⇒ JsNumber(value)
    case BSONInteger(value) ⇒ JsNumber(value)
    case BSONLong(value)    ⇒ JsNumber(value)
    case BSONBoolean(value) ⇒ JsBoolean(value)
    case BSONNull           ⇒ JsNull
    case arr: BSONArray     ⇒ JsArray(arr.values.toList.map(t ⇒ t:JsValue))
    case obj: BSONDocument  ⇒ obj:JsObject
  }

  implicit def rootJsonFormatToBsonDocumentFormat[T](rootJsonFormat: RootJsonFormat[T]): BSONDocumentFormat[T] = new BSONDocumentFormat[T] {
    def write(t: T): BSONDocument = rootJsonFormat.write(t).asJsObject
    def read(bson: BSONDocument): T = bson.convertTo[T](rootJsonFormat)
  }
}