tailrec.scala

import java.util.UUID

import scala.annotation.tailrec

/**
 * Created by Thiago Pereira on 8/4/15.
 */
case class Employee(id: UUID, name: String, parent: Option[Employee])

object TailRecTest {

  def main(args: Array[String]) {
    val president = Employee(UUID.randomUUID(), "PRESIDENT", None)
    val director = Employee(UUID.randomUUID(), "DIRECTOR", Some(president))
    val manager = Employee(UUID.randomUUID(), "MANAGER", Some(director))
    val employee = Employee(UUID.randomUUID(), "EMPLOYEE", Some(manager))

    getParents(employee).foreach(println)
  }

  def getParents(employee: Employee): List[Employee] = {
    @tailrec
    def recursion(employee: Employee, employees: List[Employee]): List[Employee] = {
      employee.parent match {
        case None => employees
        case Some(parent) =>
          recursion(parent, parent :: employees)
      }
    }

    recursion(employee, Nil)
  }
}