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/*
 * Copyright 2018 Fs2 Redis
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.github.gvolpe.fs2redis.util

import java.util.concurrent.{CompletableFuture, CompletionStage, Future}

import cats.effect.Concurrent
import cats.syntax.flatMap._
import io.lettuce.core.{ConnectionFuture, RedisFuture}

object JRFuture {

  case class EmptyValue(msg: String = "Empty value") extends Throwable(msg)

  private[fs2redis] type JFuture[A] = CompletionStage[A] with Future[A]

  def apply[F[_]: Concurrent, A](fa: F[RedisFuture[A]]): F[A] =
    liftJFuture[F, RedisFuture[A], A](fa)

  def fromConnectionFuture[F[_]: Concurrent, G[_], A](fa: F[ConnectionFuture[A]]): F[A] =
    liftJFuture[F, ConnectionFuture[A], A](fa)

  def fromCompletableFuture[F[_]: Concurrent, A](fa: F[CompletableFuture[A]]): F[A] =
    liftJFuture[F, CompletableFuture[A], A](fa)

  private[fs2redis] def liftJFuture[F[_], G <: JFuture[A], A](fa: F[G])(implicit F: Concurrent[F]): F[A] =
    fa.flatMap { f =>
      F.async[A] { cb =>
        f.handle[Unit] { (value: A, t: Throwable) =>
          if (t != null) cb(Left(t))
          else cb(Right(value))
        }
      }
    }

}