OptionF.scala

package util

import scala.concurrent.{ExecutionContext, Future}

/**
  * Future[Option[A]]のラッパー
  * @param value
  * @tparam A
  */
final case class OptionF[A](value: Future[Option[A]]) {
  def map[B](f: A => B)(implicit ec: ExecutionContext): OptionF[B] = OptionF(value.map(_.map(f)))

  def semiFlatMap[B](f: A => Future[B])(implicit ec: ExecutionContext): OptionF[B] = OptionF(value.flatMap(o => o.fold[Future[Option[B]]](Future.successful(None))(a => f(a).map(b => Some(b)))))

  def fold[B](empty: B)(f: A => B)(implicit ec: ExecutionContext): Future[B] = value.map(_.fold(empty)(f))
}

object OptionF {
  def fromOption[A](a: Option[A]): OptionF[A] = OptionF(Future.successful(a))
}