object ExampleViewerSchema {
  case class User(id: String)
  class FriendsService {
    def list(user: User): List[User] = List() // Actually filter based on your data model
  }
  class UserService {
    def authenticate: User = User("1") // Actually get a user
  }
  case class ServiceManager(friendsService: FriendsService, userService: UserService)
  case class MyContext(user: Option[User], serviceManager: ServiceManager)

  val UserType = ObjectType[MyContext, User](
    "User",
    fields = fields[MyContext, User](
      Field(
        "id",
        StringType,
        resolve = ctx => ctx.value.id
      )
    )
  )

  val ViewerType: ObjectType[MyContext, Unit] = ObjectType(
    "Viewer",
    "The current, authenticated user.",
    fields = fields[MyContext, Unit](
      Field(
        "tastings",
        ListType(UserType),
        Some("List all of the friends for a user."),
        resolve = ctx => ctx.ctx.serviceManager.friendsService.list(ctx.ctx.user.get)
      )
    )
  )

  val ViewQuery = fields[MyContext, Unit](
    Field(
      "viewer",
      ViewerType,
      Some("Information in the app scoped to the requesting user."),
      resolve = ctx => UpdateCtx(ctx.ctx.serviceManager.userService.authenticate) { user =>
        ctx.ctx.copy(user = Some(user))
      }
    )
  )

  val QueryType: ObjectType[MyContext, Unit] = ObjectType("Query",
    ViewQuery
  )

  val schema = Schema(QueryType)
}