shapless_poly_sample.scala

package com.telstra.dxhub.productmapper

import shapeless.{::, Generic, HList, HNil, Poly, Poly1}
import shapeless.PolyDefns.{Case, Case0}
import shapeless.ops.hlist.Mapper

trait ProductMapper[A, B, P] {
  def apply(a: A): B
}

object ProductMapper {
  implicit def productMapper[A, B, ARepr <: HList, BRepr <: HList, HF <: Poly](
    implicit genA: Generic.Aux[A, ARepr],
    genB: Generic.Aux[B, BRepr],
    mapper: Mapper.Aux[HF, ARepr, BRepr]
  ): ProductMapper[A, B, HF] = {
    a => genB.from(mapper.apply(genA.to(a)))
  }


  case class Afsal(x: Int)
  case class BAfsal(y: Int)

  object conversions extends Poly1 {
    implicit val intCase: Case.Aux[Int, Int] = at( _ +10)
  }

/*  implicit class ToProductMapperOps[A, B, HF](a: A)(implicit m: ProductMapper[A, B, HF]){
    def mapTo: B = m.apply(a)
  }*/

  implicit class ToProductMapper[A](a: A) {
    class Builder[B] {
      def apply[P <: Poly](poly: P)(implicit pm: ProductMapper[A, B, P]): B =
        pm.apply(a)
    }

    def mapTo[B]: Builder[B] = new Builder[B]
  }
}