using.scala

package ru.dgis.casino.advisor

//****
case class JdbcConnection() {
  def closeJdbc() = println("closing jdbc")

}

trait TTT

object TTT1 extends TTT

object TTT2 extends TTT

case class FileConnection() {
  def closeJdbc(t: TTT) = println("closing file")

}

//****

//****
trait Closeble[T] {
  def close(t: T): Unit
}

object Closeble {

  implicit object X extends Closeble[JdbcConnection] {
    override def close(c: JdbcConnection): Unit = {
      c.closeJdbc()
    }
  }

  implicit object YX extends Closeble[FileConnection] {
    override def close(c: FileConnection): Unit = {
      c.closeJdbc(TTT1)
    }
  }

  implicit def tupleCloseble[A, B](implicit a: Closeble[A], b: Closeble[B]): Closeble[(A, B)] = {
    new Closeble[(A, B)] {
      override def close(t: (A, B)): Unit = {
        a.close(t._1)
        b.close(t._2)
      }
    }
  }

  def using[T, Out](t: T)(f: T => Out)(implicit x: Closeble[T]) = {
    try {
      f(t)
    } finally {
      x.close(t)
    }
  }
}

//****

object XXX extends App {

  import Closeble._


  using(new JdbcConnection, new FileConnection) { case (jdbc1, file1) =>
    println("SSSS")

  }
    using(new JdbcConnection) { jdbc1 =>
      using(new JdbcConnection) { jdbc2 =>
        using(new FileConnection) { f =>
          println("SSSS")
        }
      }
    }
}