/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * license agreements; and to You under the Apache License, version 2.0:
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * This file is part of the Apache Pekko project, which was derived from Akka.
 */

/*
 * Copyright (C) 2009-2022 Lightbend Inc. <https://www.lightbend.com>
 */

package org.apache.pekko.stream.scaladsl

import java.util
import java.util.function.BiConsumer
import java.util.function.BinaryOperator
import java.util.function.Supplier
import java.util.function.ToIntFunction
import java.util.stream.BaseStream
import java.util.stream.Collector
import java.util.stream.Collector.Characteristics
import java.util.stream.Collectors

import scala.concurrent.Await
import scala.concurrent.duration._

import org.scalatest.time.Millis
import org.scalatest.time.Span

import org.apache.pekko
import pekko.stream.ActorAttributes
import pekko.stream.testkit.StreamSpec
import pekko.stream.testkit.Utils.TE
import pekko.testkit.DefaultTimeout
import pekko.util.ByteString

class StreamConvertersSpec extends StreamSpec with DefaultTimeout {

  implicit val config: PatienceConfig = PatienceConfig(timeout = Span(timeout.duration.toMillis, Millis))

  "Java Stream source" must {
    import java.util.stream.IntStream
    import java.util.stream.Stream

    import pekko.util.FunctionConverters._

    def javaStreamInts =
      IntStream.iterate(1,
        { (i: Int) =>
          i + 1
        }.asJava)

    "work with Java collections" in {
      val list = new java.util.LinkedList[Integer]()
      list.add(0)
      list.add(1)
      list.add(2)

      StreamConverters.fromJavaStream(() => list.stream()).map(_.intValue).runWith(Sink.seq).futureValue should ===(
        List(0, 1, 2))
    }

    "work with primitive streams" in {
      StreamConverters
        .fromJavaStream(() => IntStream.rangeClosed(1, 10))
        .map(_.intValue)
        .runWith(Sink.seq)
        .futureValue should ===(1 to 10)
    }

    "work with an empty stream" in {
      StreamConverters.fromJavaStream(() => Stream.empty[Int]()).runWith(Sink.seq).futureValue should ===(Nil)
    }

    "work with an infinite stream" in {
      StreamConverters.fromJavaStream(() => javaStreamInts).take(1000).runFold(0)(_ + _).futureValue should ===(500500)
    }

    "work with a filtered stream" in {
      StreamConverters
        .fromJavaStream(() =>
          javaStreamInts.filter({ (i: Int) =>
            i % 2 == 0
          }.asJava))
        .take(1000)
        .runFold(0)(_ + _)
        .futureValue should ===(1001000)
    }

    "properly report errors during iteration" in {
      import pekko.stream.testkit.Utils.TE
      // Filtering is lazy on Java Stream

      val failyFilter: Int => Boolean = _ => throw TE("failing filter")

      a[TE] must be thrownBy {
        Await.result(
          StreamConverters.fromJavaStream(() => javaStreamInts.filter(failyFilter.asJava)).runWith(Sink.ignore),
          3.seconds)
      }
    }

    "close the underlying stream when completed" in {
      @volatile var closed = false

      final class EmptyStream extends BaseStream[Unit, EmptyStream] {
        override def unordered(): EmptyStream = this
        override def sequential(): EmptyStream = this
        override def parallel(): EmptyStream = this
        override def isParallel: Boolean = false

        override def spliterator(): util.Spliterator[Unit] = ???
        override def onClose(closeHandler: Runnable): EmptyStream = ???

        override def iterator(): util.Iterator[Unit] = new util.Iterator[Unit] {
          override def next(): Unit = ???
          override def hasNext: Boolean = false
        }

        override def close(): Unit = closed = true
      }

      Await.ready(StreamConverters.fromJavaStream(() => new EmptyStream).runWith(Sink.ignore), 3.seconds)

      closed should ===(true)
    }

    "close the underlying stream when failed" in {
      @volatile var closed = false

      final class FailingStream extends BaseStream[Unit, FailingStream] {
        override def unordered(): FailingStream = this
        override def sequential(): FailingStream = this
        override def parallel(): FailingStream = this
        override def isParallel: Boolean = false

        override def spliterator(): util.Spliterator[Unit] = ???
        override def onClose(closeHandler: Runnable): FailingStream = ???

        override def iterator(): util.Iterator[Unit] = new util.Iterator[Unit] {
          override def next(): Unit = throw new TE("ouch")
          override def hasNext: Boolean = true
        }

        override def close(): Unit = closed = true
      }

      Await.ready(StreamConverters.fromJavaStream(() => new FailingStream).runWith(Sink.ignore), 3.seconds)

      closed should ===(true)
    }

    // Repeater for #24304
    "not throw stack overflow with a large source" in {
      Source
        .repeat(Integer.valueOf(1))
        .take(100000)
        .runWith(StreamConverters.javaCollector[Integer, Integer] { () =>
          Collectors.summingInt(new ToIntFunction[Integer] {
            def applyAsInt(value: Integer): Int = value
          })
        })
        .futureValue
    }

    "not share collector across materializations" in {
      val stream = Source
        .repeat(1)
        .take(10)
        .toMat(StreamConverters.javaCollector[Int, Integer] { () =>
          Collectors.summingInt(new ToIntFunction[Int] {
            def applyAsInt(value: Int): Int = value
          })
        })(Keep.right)
      stream.run().futureValue should ===(Integer.valueOf(10))
      stream.run().futureValue should ===(Integer.valueOf(10))
    }

  }

  "Java collector Sink" must {

    class TestCollector(
        _supplier: () => Supplier[Array[Int]],
        _accumulator: () => BiConsumer[Array[Int], Int],
        _combiner: () => BinaryOperator[Array[Int]],
        _finisher: () => java.util.function.Function[Array[Int], Int])
        extends Collector[Int, Array[Int], Int] {
      override def supplier(): Supplier[Array[Int]] = _supplier()
      override def combiner(): BinaryOperator[Array[Int]] = _combiner()
      override def finisher(): java.util.function.Function[Array[Int], Int] = _finisher()
      override def accumulator(): BiConsumer[Array[Int], Int] = _accumulator()
      override def characteristics(): util.Set[Characteristics] = util.Collections.emptySet()
    }

    val intIdentity: ToIntFunction[Int] = new ToIntFunction[Int] {
      override def applyAsInt(value: Int): Int = value
    }

    def supplier(): Supplier[Array[Int]] = new Supplier[Array[Int]] {
      override def get(): Array[Int] = new Array(1)
    }
    def accumulator(): BiConsumer[Array[Int], Int] = new BiConsumer[Array[Int], Int] {
      override def accept(a: Array[Int], b: Int): Unit = a(0) = intIdentity.applyAsInt(b)
    }

    def combiner(): BinaryOperator[Array[Int]] = new BinaryOperator[Array[Int]] {
      override def apply(a: Array[Int], b: Array[Int]): Array[Int] = {
        a(0) += b(0); a
      }
    }
    def finisher(): java.util.function.Function[Array[Int], Int] = new java.util.function.Function[Array[Int], Int] {
      override def apply(a: Array[Int]): Int = a(0)
    }

    "work in the happy case" in {
      Source(1 to 100)
        .map(_.toString)
        .runWith(StreamConverters.javaCollector(() => Collectors.joining(", ")))
        .futureValue should ===((1 to 100).mkString(", "))
    }

    "work with an empty source" in {
      Source
        .empty[Int]
        .map(_.toString)
        .runWith(StreamConverters.javaCollector(() => Collectors.joining(", ")))
        .futureValue should ===("")
    }

    "work parallelly in the happy case" in {
      Source(1 to 100)
        .runWith(StreamConverters.javaCollectorParallelUnordered(4)(() => Collectors.summingInt[Int](intIdentity)))
        .futureValue
        .toInt should ===(5050)
    }

    "work parallelly with an empty source" in {
      Source
        .empty[Int]
        .map(_.toString)
        .runWith(StreamConverters.javaCollectorParallelUnordered(4)(() => Collectors.joining(", ")))
        .futureValue should ===("")
    }

    "be reusable" in {
      val sink = StreamConverters.javaCollector[Int, Integer](() => Collectors.summingInt[Int](intIdentity))
      Source(1 to 4).runWith(sink).futureValue.toInt should ===(10)

      // Collector has state so it preserves all previous elements that went though
      Source(4 to 6).runWith(sink).futureValue.toInt should ===(15)
    }

    "be reusable with parallel version" in {
      val sink = StreamConverters.javaCollectorParallelUnordered(4)(() => Collectors.summingInt[Int](intIdentity))

      Source(1 to 4).runWith(sink).futureValue.toInt should ===(10)
      Source(4 to 6).runWith(sink).futureValue.toInt should ===(15)
    }

    "fail if getting the supplier fails" in {
      def failedSupplier(): Supplier[Array[Int]] = throw TE("")
      val future = Source(1 to 100).runWith(StreamConverters.javaCollector(() =>
        new TestCollector(failedSupplier _, accumulator _, combiner _, finisher _)))
      a[TE] shouldBe thrownBy {
        Await.result(future, 300.millis)
      }
    }

    "fail if the supplier fails" in {
      def failedSupplier(): Supplier[Array[Int]] = new Supplier[Array[Int]] {
        override def get(): Array[Int] = throw TE("")
      }
      val future = Source(1 to 100).runWith(StreamConverters.javaCollector(() =>
        new TestCollector(failedSupplier _, accumulator _, combiner _, finisher _)))
      a[TE] shouldBe thrownBy {
        Await.result(future, 300.millis)
      }
    }

    "fail if getting the accumulator fails" in {
      def failedAccumulator(): BiConsumer[Array[Int], Int] = throw TE("")

      val future = Source(1 to 100).runWith(StreamConverters.javaCollector(() =>
        new TestCollector(supplier _, failedAccumulator _, combiner _, finisher _)))
      a[TE] shouldBe thrownBy {
        Await.result(future, 300.millis)
      }
    }

    "fail if the accumulator fails" in {
      def failedAccumulator(): BiConsumer[Array[Int], Int] = new BiConsumer[Array[Int], Int] {
        override def accept(a: Array[Int], b: Int): Unit = throw TE("")
      }

      val future = Source(1 to 100).runWith(StreamConverters.javaCollector(() =>
        new TestCollector(supplier _, failedAccumulator _, combiner _, finisher _)))
      a[TE] shouldBe thrownBy {
        Await.result(future, 300.millis)
      }
    }

    "fail if getting the finisher fails" in {
      def failedFinisher(): java.util.function.Function[Array[Int], Int] = throw TE("")

      val future = Source(1 to 100).runWith(StreamConverters.javaCollector(() =>
        new TestCollector(supplier _, accumulator _, combiner _, failedFinisher _)))
      a[TE] shouldBe thrownBy {
        Await.result(future, 300.millis)
      }
    }

    "fail if the finisher fails" in {
      def failedFinisher(): java.util.function.Function[Array[Int], Int] =
        new java.util.function.Function[Array[Int], Int] {
          override def apply(a: Array[Int]): Int = throw TE("")
        }
      val future = Source(1 to 100).runWith(StreamConverters.javaCollector(() =>
        new TestCollector(supplier _, accumulator _, combiner _, failedFinisher _)))
      a[TE] shouldBe thrownBy {
        Await.result(future, 300.millis)
      }
    }
  }

  "InputStream Sink" must {
    "produce a single value" in {
      val source = Source.single(ByteString("ASDF"))
      val sink =
        StreamConverters.asInputStream().withAttributes(ActorAttributes.dispatcher("pekko.test.stream-dispatcher"))

      val is = source.runWith(sink)
      is.read() should be('A')
      val target = Array[Byte](0, 0, 0)
      is.read(target, 1, 2)
      target should be(Array[Byte](0, 'S', 'D'))
      is.read() should be('F')
      is.read() should be(-1)
      is.close()
    }
    // As specified in the Closeable interface, #28664
    "withstand being closed twice" in {
      val source = Source.single(ByteString("ASDF"))
      val sink =
        StreamConverters.asInputStream().withAttributes(ActorAttributes.dispatcher("pekko.test.stream-dispatcher"))

      val is = source.runWith(sink)
      is.read() should be('A')
      is.close()
      is.close()
    }
  }

  "OutputStream Source" must {
    "ignore empty arrays" in {
      val source =
        StreamConverters.asOutputStream().withAttributes(ActorAttributes.dispatcher("pekko.test.stream-dispatcher"))

      val (out, result) = source.toMat(Sink.seq)(Keep.both).run()

      out.write(1)
      out.write(Array[Byte](2, 3, 4))
      out.write(Array[Byte]())
      out.write(5)
      out.write(Array(6, 7, 8), 0, 3)
      out.write(Array(), 0, 0)
      out.write(9)
      out.close()

      result.futureValue should contain theSameElementsInOrderAs Seq(
        ByteString(1),
        ByteString(2, 3, 4),
        ByteString(5),
        ByteString(6, 7, 8),
        ByteString(9))
    }
  }
}
