gistfile1.scala

package app.models.world

import java.util.UUID

import shapeless._
import shapeless.ops.record.Selector
import shapeless.record._
import shapeless.syntax.singleton._

trait WObjectStats

object WObject {
  type Id = UUID
  def newId: Id = UUID.randomUUID()

  private object Witnesses {
    val id = Witness("id")
    val position = Witness("position")
  }

  private object Selectors {
    type Id = Selector[Witnesses.id.T, UUID]
    type Position = Selector[Witnesses.position.T, Vect2]
  }
}

/* World object */
abstract class WObject[A <: HList](val props: A)(implicit
  idSel: WObject.Selectors.Id, positionSel: WObject.Selectors.Position
) {
  def this(id: WObject.Id, position: Vect2) =
    this("id" ->> id :: "position" ->> position :: HNil)

  def id = props("id")
  def position = props("position")
  def withId(id: WObject.Id) = props

  def stats: Stats
  lazy val bounds = Bounds(position, Vect2.one)
}