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// Copyright: 2010 - 2018 https://github.com/ensime/ensime-server/graphs
// License: http://www.gnu.org/licenses/lgpl-3.0.en.html
package spray.json

import scala.{ Left, Right }

/**
 * Provides the JsonFormats for the non-collection standard types.
 */
trait StandardFormats {
  this: AdditionalFormats =>

  private[json] type JF[T] = JsonFormat[T] // simple alias for reduced verbosity

  implicit def optionFormat[T: JF]: JF[Option[T]] = new OptionFormat[T]

  class OptionFormat[T: JF] extends JF[Option[T]] {
    def write(option: Option[T]) = option match {
      case Some(x) => x.toJson
      case None    => JsNull
    }
    def read(value: JsValue) = value match {
      case JsNull => None
      case x      => Some(x.convertTo[T])
    }
    // allows reading the JSON as a Some (useful in container formats)
    def readSome(value: JsValue) = Some(value.convertTo[T])
  }

  implicit def eitherFormat[A: JF, B: JF] = new JF[Either[A, B]] {
    def write(either: Either[A, B]) = either match {
      case Right(a) => a.toJson
      case Left(b)  => b.toJson
    }
    def read(value: JsValue) =
      (value.convertTo(safeReader[A]), value.convertTo(safeReader[B])) match {
        case (Right(a), _: Left[_, _]) => Left(a)
        case (_: Left[_, _], Right(b)) => Right(b)
        case (_: Right[_, _], _: Right[_, _]) =>
          deserializationError(
            "Ambiguous Either value: can be read as both, Left and Right, values"
          )
        case (Left(ea), Left(eb)) =>
          deserializationError(
            "Could not read Either value:\n" + ea + "---------- and ----------\n" + eb
          )
      }
  }

  implicit def tuple1Format[A: JF] = new JF[Tuple1[A]] {
    def write(t: Tuple1[A])  = t._1.toJson
    def read(value: JsValue) = Tuple1(value.convertTo[A])
  }

  implicit def tuple2Format[A: JF, B: JF] = new RootJsonFormat[(A, B)] {
    def write(t: (A, B)) = JsArray(t._1.toJson, t._2.toJson)
    def read(value: JsValue) = value match {
      case JsArray(Seq(a, b)) => (a.convertTo[A], b.convertTo[B])
      case x                  => deserializationError("Expected Tuple2 as JsArray, but got " + x)
    }
  }

  implicit def tuple3Format[A: JF, B: JF, C: JF] =
    new RootJsonFormat[(A, B, C)] {
      def write(t: (A, B, C)) = JsArray(t._1.toJson, t._2.toJson, t._3.toJson)
      def read(value: JsValue) = value match {
        case JsArray(Seq(a, b, c)) =>
          (a.convertTo[A], b.convertTo[B], c.convertTo[C])
        case x =>
          deserializationError("Expected Tuple3 as JsArray, but got " + x)
      }
    }

  implicit def tuple4Format[A: JF, B: JF, C: JF, D: JF] =
    new RootJsonFormat[(A, B, C, D)] {
      def write(t: (A, B, C, D)) =
        JsArray(t._1.toJson, t._2.toJson, t._3.toJson, t._4.toJson)
      def read(value: JsValue) = value match {
        case JsArray(Seq(a, b, c, d)) =>
          (a.convertTo[A], b.convertTo[B], c.convertTo[C], d.convertTo[D])
        case x =>
          deserializationError("Expected Tuple4 as JsArray, but got " + x)
      }
    }

  implicit def tuple5Format[A: JF, B: JF, C: JF, D: JF, E: JF] =
    new RootJsonFormat[(A, B, C, D, E)] {
      def write(t: (A, B, C, D, E)) =
        JsArray(t._1.toJson, t._2.toJson, t._3.toJson, t._4.toJson, t._5.toJson)
      def read(value: JsValue) = value match {
        case JsArray(Seq(a, b, c, d, e)) =>
          (a.convertTo[A],
           b.convertTo[B],
           c.convertTo[C],
           d.convertTo[D],
           e.convertTo[E])
        case x =>
          deserializationError("Expected Tuple5 as JsArray, but got " + x)
      }
    }

  implicit def tuple6Format[A: JF, B: JF, C: JF, D: JF, E: JF, F: JF] =
    new RootJsonFormat[(A, B, C, D, E, F)] {
      def write(t: (A, B, C, D, E, F)) =
        JsArray(t._1.toJson,
                t._2.toJson,
                t._3.toJson,
                t._4.toJson,
                t._5.toJson,
                t._6.toJson)
      def read(value: JsValue) = value match {
        case JsArray(Seq(a, b, c, d, e, f)) =>
          (a.convertTo[A],
           b.convertTo[B],
           c.convertTo[C],
           d.convertTo[D],
           e.convertTo[E],
           f.convertTo[F])
        case x =>
          deserializationError("Expected Tuple6 as JsArray, but got " + x)
      }
    }

  implicit def tuple7Format[A: JF, B: JF, C: JF, D: JF, E: JF, F: JF, G: JF] =
    new RootJsonFormat[(A, B, C, D, E, F, G)] {
      def write(t: (A, B, C, D, E, F, G)) =
        JsArray(t._1.toJson,
                t._2.toJson,
                t._3.toJson,
                t._4.toJson,
                t._5.toJson,
                t._6.toJson,
                t._7.toJson)
      def read(value: JsValue) = value match {
        case JsArray(Seq(a, b, c, d, e, f, g)) =>
          (a.convertTo[A],
           b.convertTo[B],
           c.convertTo[C],
           d.convertTo[D],
           e.convertTo[E],
           f.convertTo[F],
           g.convertTo[G])
        case x =>
          deserializationError("Expected Tuple7 as JsArray, but got " + x)
      }
    }

}