/*
 * 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) 2014-2022 Lightbend Inc. <https://www.lightbend.com>
 */

package org.apache.pekko.stream

import java.util.concurrent.TimeUnit

import scala.annotation.nowarn
import scala.concurrent.duration._
import scala.util.control.NoStackTrace

import org.apache.pekko
import pekko.actor.ActorContext
import pekko.actor.ActorRef
import pekko.actor.ActorRefFactory
import pekko.actor.ActorSystem
import pekko.actor.ExtendedActorSystem
import pekko.actor.Props
import pekko.annotation.InternalApi
import pekko.event.LoggingAdapter
import pekko.japi.function
import pekko.stream.impl._
import pekko.stream.stage.GraphStageLogic
import pekko.util.Helpers.toRootLowerCase

import com.typesafe.config.Config
import com.typesafe.config.ConfigFactory

object ActorMaterializer {

  /**
   * Scala API: Creates an ActorMaterializer that can materialize stream blueprints as running streams.
   *
   * The required [[pekko.actor.ActorRefFactory]] (which can be either an [[pekko.actor.ActorSystem]] or an [[pekko.actor.ActorContext]])
   * will be used to create one actor that in turn creates actors for the transformation steps.
   *
   * The materializer's [[pekko.stream.ActorMaterializerSettings]] will be obtained from the
   * configuration of the `context`'s underlying [[pekko.actor.ActorSystem]].
   *
   * The `namePrefix` is used as the first part of the names of the actors running
   * the processing steps. The default `namePrefix` is `"flow"`. The actor names are built up of
   * `namePrefix-flowNumber-flowStepNumber-stepName`.
   */
  @deprecated(
    "Use the system wide materializer with stream attributes or configuration settings to change defaults",
    "Akka 2.6.0")
  def apply(materializerSettings: Option[ActorMaterializerSettings] = None, namePrefix: Option[String] = None)(
      implicit context: ActorRefFactory): ActorMaterializer = {
    val system = actorSystemOf(context)

    val settings = materializerSettings.getOrElse(SystemMaterializer(system).materializerSettings)
    apply(settings, namePrefix.getOrElse("flow"))(context)
  }

  /**
   * Scala API: Creates an ActorMaterializer that can materialize stream blueprints as running streams.
   *
   * The required [[pekko.actor.ActorRefFactory]]
   * (which can be either an [[pekko.actor.ActorSystem]] or an [[pekko.actor.ActorContext]])
   * will be used to create these actors, therefore it is *forbidden* to pass this object
   * to another actor if the factory is an ActorContext.
   *
   * The `namePrefix` is used as the first part of the names of the actors running
   * the processing steps. The default `namePrefix` is `"flow"`. The actor names are built up of
   * `namePrefix-flowNumber-flowStepNumber-stepName`.
   */
  @deprecated(
    "Use the system wide materializer with stream attributes or configuration settings to change defaults",
    "Akka 2.6.0")
  def apply(materializerSettings: ActorMaterializerSettings, namePrefix: String)(
      implicit context: ActorRefFactory): ActorMaterializer = {

    context match {
      case system: ActorSystem =>
        // system level materializer, defer to the system materializer extension
        SystemMaterializer(system)
          .createAdditionalLegacySystemMaterializer(namePrefix, materializerSettings)
          .asInstanceOf[ActorMaterializer]

      case context: ActorContext =>
        // actor context level materializer, will live as a child of this actor
        PhasedFusingActorMaterializer(context, namePrefix, materializerSettings, materializerSettings.toAttributes)

      case other =>
        throw new IllegalArgumentException(s"Unexpected type of context: $other")
    }
  }

  /**
   * Scala API: Creates an ActorMaterializer that can materialize stream blueprints as running streams.
   *
   * The required [[pekko.actor.ActorRefFactory]]
   * (which can be either an [[pekko.actor.ActorSystem]] or an [[pekko.actor.ActorContext]])
   * will be used to create these actors, therefore it is *forbidden* to pass this object
   * to another actor if the factory is an ActorContext.
   *
   * The `namePrefix` is used as the first part of the names of the actors running
   * the processing steps. The default `namePrefix` is `"flow"`. The actor names are built up of
   * `namePrefix-flowNumber-flowStepNumber-stepName`.
   */
  @deprecated(
    "Use the system wide materializer or Materializer.apply(actorContext) with stream attributes or configuration settings to change defaults",
    "Akka 2.6.0")
  def apply(materializerSettings: ActorMaterializerSettings)(implicit context: ActorRefFactory): ActorMaterializer =
    apply(Some(materializerSettings), None)

  /**
   * Java API: Creates an ActorMaterializer that can materialize stream blueprints as running streams.
   *
   * The required [[pekko.actor.ActorRefFactory]]
   * (which can be either an [[pekko.actor.ActorSystem]] or an [[pekko.actor.ActorContext]])
   * will be used to create these actors, therefore it is *forbidden* to pass this object
   * to another actor if the factory is an ActorContext.
   *
   * Defaults the actor name prefix used to name actors running the processing steps to `"flow"`.
   * The actor names are built up of `namePrefix-flowNumber-flowStepNumber-stepName`.
   */
  @deprecated(
    "Use the system wide materializer or Materializer.create(actorContext) with stream attributes or configuration settings to change defaults",
    "Akka 2.6.0")
  def create(context: ActorRefFactory): ActorMaterializer =
    apply()(context)

  /**
   * Java API: Creates an ActorMaterializer that can materialize stream blueprints as running streams.
   *
   * The required [[pekko.actor.ActorRefFactory]]
   * (which can be either an [[pekko.actor.ActorSystem]] or an [[pekko.actor.ActorContext]])
   * will be used to create these actors, therefore it is *forbidden* to pass this object
   * to another actor if the factory is an ActorContext.
   *
   * The `namePrefix` is used as the first part of the names of the actors running
   * the processing steps. The default `namePrefix` is `"flow"`. The actor names are built up of
   * `namePrefix-flowNumber-flowStepNumber-stepName`.
   */
  @deprecated(
    "Use the system wide materializer or Materializer.create(actorContext) with stream attributes or configuration settings to change defaults",
    "Akka 2.6.0")
  def create(context: ActorRefFactory, namePrefix: String): ActorMaterializer = {
    val system = actorSystemOf(context)
    val settings = ActorMaterializerSettings(system)
    apply(settings, namePrefix)(context)
  }

  /**
   * Java API: Creates an ActorMaterializer that can materialize stream blueprints as running streams.
   *
   * The required [[pekko.actor.ActorRefFactory]]
   * (which can be either an [[pekko.actor.ActorSystem]] or an [[pekko.actor.ActorContext]])
   * will be used to create one actor that in turn creates actors for the transformation steps.
   */
  @deprecated(
    "Use the system wide materializer or Materializer.create(actorContext) with stream attributes or configuration settings to change defaults",
    "Akka 2.6.0")
  def create(settings: ActorMaterializerSettings, context: ActorRefFactory): ActorMaterializer =
    apply(Option(settings), None)(context)

  /**
   * Java API: Creates an ActorMaterializer that can materialize stream blueprints as running streams.
   *
   * The required [[pekko.actor.ActorRefFactory]]
   * (which can be either an [[pekko.actor.ActorSystem]] or an [[pekko.actor.ActorContext]])
   * will be used to create these actors, therefore it is *forbidden* to pass this object
   * to another actor if the factory is an ActorContext.
   *
   * The `namePrefix` is used as the first part of the names of the actors running
   * the processing steps. The default `namePrefix` is `"flow"`. The actor names are built up of
   * `namePrefix-flowNumber-flowStepNumber-stepName`.
   */
  @deprecated(
    "Use the system wide materializer or Materializer.create(actorContext) with stream attributes or configuration settings to change defaults",
    "Akka 2.6.0")
  def create(settings: ActorMaterializerSettings, context: ActorRefFactory, namePrefix: String): ActorMaterializer =
    apply(Option(settings), Option(namePrefix))(context)

  private def actorSystemOf(context: ActorRefFactory): ActorSystem = {
    val system = context match {
      case s: ExtendedActorSystem => s
      case c: ActorContext        => c.system
      case null                   => throw new IllegalArgumentException("ActorRefFactory context must be defined")
      case _                      =>
        throw new IllegalArgumentException(
          s"ActorRefFactory context must be an ActorSystem or ActorContext, got [${context.getClass.getName}]")
    }
    system
  }

}

/**
 * INTERNAL API
 */
private[pekko] object ActorMaterializerHelper {

  /**
   * INTERNAL API
   */
  @deprecated("The Materializer now has all methods the ActorMaterializer used to have", "Akka 2.6.0")
  private[pekko] def downcast(materializer: Materializer): ActorMaterializer =
    materializer match {
      case m: ActorMaterializer => m
      case _                    =>
        throw new IllegalArgumentException(
          s"required [${classOf[ActorMaterializer].getName}] " +
          s"but got [${materializer.getClass.getName}]")
    }
}

/**
 * An ActorMaterializer takes a stream blueprint and turns it into a running stream.
 */
@deprecated("The Materializer now has all methods the ActorMaterializer used to have", "Akka 2.6.0")
abstract class ActorMaterializer extends Materializer with MaterializerLoggingProvider {

  @deprecated(
    "Use attributes to access settings from stages, see https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html",
    "Akka 2.6.0")
  def settings: ActorMaterializerSettings

  /**
   * Shuts down this materializer and all the operators that have been materialized through this materializer. After
   * having shut down, this materializer cannot be used again. Any attempt to materialize operators after having
   * shut down will result in an IllegalStateException being thrown at materialization time.
   */
  def shutdown(): Unit

  /**
   * Indicates if the materializer has been shut down.
   */
  def isShutdown: Boolean

  /**
   * INTERNAL API
   */
  private[pekko] def actorOf(context: MaterializationContext, props: Props): ActorRef

  /**
   * INTERNAL API
   */
  def system: ActorSystem

  /**
   * INTERNAL API
   */
  private[pekko] def logger: LoggingAdapter

  /**
   * INTERNAL API
   */
  private[pekko] def supervisor: ActorRef

}

/**
 * This exception or subtypes thereof should be used to signal materialization
 * failures.
 */
class MaterializationException(msg: String, cause: Throwable = null) extends RuntimeException(msg, cause)

/**
 * A base exception for abrupt stream termination.
 */
sealed class AbruptStreamTerminationException(msg: String, cause: Throwable)
    extends RuntimeException(msg, cause)
    with NoStackTrace

/**
 * This exception signals that an actor implementing a Reactive Streams Subscriber, Publisher or Processor
 * has been terminated without being notified by an onError, onComplete or cancel signal. This usually happens
 * when an ActorSystem is shut down while stream processing actors are still running.
 */
final case class AbruptTerminationException(actor: ActorRef)
    extends AbruptStreamTerminationException(s"Processor actor [$actor] terminated abruptly", cause = null)

/**
 * Signal that the operator was abruptly terminated, usually seen as a call to `postStop` of the `GraphStageLogic` without
 * any of the handler callbacks seeing completion or failure from upstream or cancellation from downstream. This can happen when
 * the actor running the graph is killed, which happens when the materializer or actor system is terminated.
 */
final class AbruptStageTerminationException(logic: GraphStageLogic)
    extends AbruptStreamTerminationException(
      s"GraphStage [$logic] terminated abruptly, caused by for example materializer or actor system termination.",
      cause = null)

object ActorMaterializerSettings {

  /**
   * Create [[ActorMaterializerSettings]] from individual settings (Scala).
   *
   * Prefer using either config for defaults or attributes for per-stream config.
   * See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html"
   */
  @deprecated(
    "Use config or attributes to configure the materializer. See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html",
    "Akka 2.6.0")
  def apply(
      initialInputBufferSize: Int,
      maxInputBufferSize: Int,
      dispatcher: String,
      supervisionDecider: Supervision.Decider,
      subscriptionTimeoutSettings: StreamSubscriptionTimeoutSettings,
      debugLogging: Boolean,
      outputBurstLimit: Int,
      fuzzingMode: Boolean,
      autoFusing: Boolean,
      maxFixedBufferSize: Int) = {
    // these sins were committed in the name of bin comp:
    val config = ConfigFactory.defaultReference
    new ActorMaterializerSettings(
      initialInputBufferSize,
      maxInputBufferSize,
      dispatcher,
      supervisionDecider,
      subscriptionTimeoutSettings,
      debugLogging,
      outputBurstLimit,
      fuzzingMode,
      autoFusing,
      maxFixedBufferSize,
      1000,
      IOSettings(tcpWriteBufferSize = 16 * 1024),
      StreamRefSettings(config.getConfig("pekko.stream.materializer.stream-ref")),
      config.getString(ActorAttributes.IODispatcher.dispatcher))
  }

  /**
   * Create [[ActorMaterializerSettings]] from the settings of an [[pekko.actor.ActorSystem]] (Scala).
   *
   * Prefer using either config for defaults or attributes for per-stream config.
   * See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html"
   */
  @deprecated(
    "Use config or attributes to configure the materializer. See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html",
    "Akka 2.6.0")
  def apply(system: ActorSystem): ActorMaterializerSettings =
    apply(system.settings.config.getConfig("pekko.stream.materializer"))

  /**
   * Create [[ActorMaterializerSettings]] from a Config subsection (Scala).
   *
   * Prefer using either config for defaults or attributes for per-stream config.
   * See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html"
   */
  @deprecated(
    "Use config or attributes to configure the materializer. See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html",
    "Akka 2.6.0")
  def apply(config: Config): ActorMaterializerSettings =
    new ActorMaterializerSettings(
      initialInputBufferSize = config.getInt("initial-input-buffer-size"),
      maxInputBufferSize = config.getInt("max-input-buffer-size"),
      dispatcher = config.getString("dispatcher"),
      supervisionDecider = Supervision.stoppingDecider,
      subscriptionTimeoutSettings = StreamSubscriptionTimeoutSettings(config),
      debugLogging = config.getBoolean("debug-logging"),
      outputBurstLimit = config.getInt("output-burst-limit"),
      fuzzingMode = config.getBoolean("debug.fuzzing-mode"),
      autoFusing = config.getBoolean("auto-fusing"),
      maxFixedBufferSize = config.getInt("max-fixed-buffer-size"),
      syncProcessingLimit = config.getInt("sync-processing-limit"),
      ioSettings = IOSettings(config.getConfig("io")),
      streamRefSettings = StreamRefSettings(config.getConfig("stream-ref")),
      blockingIoDispatcher = config.getString("blocking-io-dispatcher"))

  /**
   * Create [[ActorMaterializerSettings]] from individual settings (Java).
   *
   * Prefer using either config for defaults or attributes for per-stream config.
   * See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html"
   */
  @deprecated(
    "Use config or attributes to configure the materializer. See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html",
    "Akka 2.6.0")
  def create(
      initialInputBufferSize: Int,
      maxInputBufferSize: Int,
      dispatcher: String,
      supervisionDecider: Supervision.Decider,
      subscriptionTimeoutSettings: StreamSubscriptionTimeoutSettings,
      debugLogging: Boolean,
      outputBurstLimit: Int,
      fuzzingMode: Boolean,
      autoFusing: Boolean,
      maxFixedBufferSize: Int) = {
    // these sins were committed in the name of bin comp:
    val config = ConfigFactory.defaultReference
    new ActorMaterializerSettings(
      initialInputBufferSize,
      maxInputBufferSize,
      dispatcher,
      supervisionDecider,
      subscriptionTimeoutSettings,
      debugLogging,
      outputBurstLimit,
      fuzzingMode,
      autoFusing,
      maxFixedBufferSize,
      1000,
      IOSettings(tcpWriteBufferSize = 16 * 1024),
      StreamRefSettings(config.getConfig("pekko.stream.materializer.stream-ref")),
      config.getString(ActorAttributes.IODispatcher.dispatcher))
  }

  /**
   * Create [[ActorMaterializerSettings]] from the settings of an [[pekko.actor.ActorSystem]] (Java).
   */
  @deprecated(
    "Use config or attributes to configure the materializer. See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html",
    "Akka 2.6.0")
  def create(system: ActorSystem): ActorMaterializerSettings =
    apply(system)

  /**
   * Create [[ActorMaterializerSettings]] from a Config subsection (Java).
   *
   * Prefer using either config for defaults or attributes for per-stream config.
   * See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html"
   */
  @deprecated(
    "Use config or attributes to configure the materializer. See migration guide for details https://doc.akka.io/docs/akka/2.6/project/migration-guide-2.5.x-2.6.x.html",
    "Akka 2.6.0")
  def create(config: Config): ActorMaterializerSettings =
    apply(config)

}

/**
 * This class describes the configurable properties of the [[ActorMaterializer]].
 * Please refer to the `withX` methods for descriptions of the individual settings.
 *
 * The constructor is not public API, use create or apply on the [[ActorMaterializerSettings]] companion instead.
 */
@nowarn("msg=deprecated")
final class ActorMaterializerSettings @InternalApi private (
    /*
     * Important note: `initialInputBufferSize`, `maxInputBufferSize`, `dispatcher` and
     * `supervisionDecider` must not be used as values in the materializer, or anything the materializer phases use
     * since these settings allow for overriding using [[Attributes]]. They must always be gotten from the effective
     * attributes.
     */
    @deprecated("Use attribute 'Attributes.InputBuffer' to read the concrete setting value", "Akka 2.6.0")
    val initialInputBufferSize: Int,
    @deprecated("Use attribute 'Attributes.InputBuffer' to read the concrete setting value", "Akka 2.6.0")
    val maxInputBufferSize: Int,
    @deprecated("Use attribute 'ActorAttributes.Dispatcher' to read the concrete setting value", "Akka 2.6.0")
    val dispatcher: String,
    @deprecated("Use attribute 'ActorAttributes.SupervisionStrategy' to read the concrete setting value", "Akka 2.6.0")
    val supervisionDecider: Supervision.Decider,
    val subscriptionTimeoutSettings: StreamSubscriptionTimeoutSettings,
    @deprecated("Use attribute 'ActorAttributes.DebugLogging' to read the concrete setting value", "Akka 2.6.0")
    val debugLogging: Boolean,
    @deprecated("Use attribute 'ActorAttributes.OutputBurstLimit' to read the concrete setting value", "Akka 2.6.0")
    val outputBurstLimit: Int,
    @deprecated("Use attribute 'ActorAttributes.FuzzingMode' to read the concrete setting value", "Akka 2.6.0")
    val fuzzingMode: Boolean,
    @deprecated("No longer has any effect", "Akka 2.6.0")
    val autoFusing: Boolean,
    @deprecated("Use attribute 'ActorAttributes.MaxFixedBufferSize' to read the concrete setting value", "Akka 2.6.0")
    val maxFixedBufferSize: Int,
    @deprecated("Use attribute 'ActorAttributes.SyncProcessingLimit' to read the concrete setting value", "Akka 2.6.0")
    val syncProcessingLimit: Int,
    val ioSettings: IOSettings,
    val streamRefSettings: StreamRefSettings,
    @deprecated("Use attribute 'ActorAttributes.BlockingIoDispatcher' to read the concrete setting value", "Akka 2.6.0")
    val blockingIoDispatcher: String) {

  require(initialInputBufferSize > 0, "initialInputBufferSize must be > 0")
  require(syncProcessingLimit > 0, "syncProcessingLimit must be > 0")

  requirePowerOfTwo(maxInputBufferSize, "maxInputBufferSize")
  require(
    initialInputBufferSize <= maxInputBufferSize,
    s"initialInputBufferSize($initialInputBufferSize) must be <= maxInputBufferSize($maxInputBufferSize)")

  // backwards compatibility when added IOSettings, shouldn't be needed since private, but added to satisfy mima
  @deprecated("Use ActorMaterializerSettings.apply or ActorMaterializerSettings.create instead", "Akka 2.5.10")
  def this(
      initialInputBufferSize: Int,
      maxInputBufferSize: Int,
      dispatcher: String,
      supervisionDecider: Supervision.Decider,
      subscriptionTimeoutSettings: StreamSubscriptionTimeoutSettings,
      debugLogging: Boolean,
      outputBurstLimit: Int,
      fuzzingMode: Boolean,
      autoFusing: Boolean,
      maxFixedBufferSize: Int,
      syncProcessingLimit: Int,
      ioSettings: IOSettings) =
    // using config like this is not quite right but the only way to solve backwards comp without hard coding settings
    this(
      initialInputBufferSize,
      maxInputBufferSize,
      dispatcher,
      supervisionDecider,
      subscriptionTimeoutSettings,
      debugLogging,
      outputBurstLimit,
      fuzzingMode,
      autoFusing,
      maxFixedBufferSize,
      syncProcessingLimit,
      ioSettings,
      StreamRefSettings(ConfigFactory.defaultReference().getConfig("pekko.stream.materializer.stream-ref")),
      ConfigFactory.defaultReference().getString(ActorAttributes.IODispatcher.dispatcher))

  // backwards compatibility when added IOSettings, shouldn't be needed since private, but added to satisfy mima
  @deprecated("Use ActorMaterializerSettings.apply or ActorMaterializerSettings.create instead", "Akka 2.5.10")
  def this(
      initialInputBufferSize: Int,
      maxInputBufferSize: Int,
      dispatcher: String,
      supervisionDecider: Supervision.Decider,
      subscriptionTimeoutSettings: StreamSubscriptionTimeoutSettings,
      debugLogging: Boolean,
      outputBurstLimit: Int,
      fuzzingMode: Boolean,
      autoFusing: Boolean,
      maxFixedBufferSize: Int,
      syncProcessingLimit: Int) =
    // using config like this is not quite right but the only way to solve backwards comp without hard coding settings
    this(
      initialInputBufferSize,
      maxInputBufferSize,
      dispatcher,
      supervisionDecider,
      subscriptionTimeoutSettings,
      debugLogging,
      outputBurstLimit,
      fuzzingMode,
      autoFusing,
      maxFixedBufferSize,
      syncProcessingLimit,
      IOSettings(tcpWriteBufferSize = 16 * 1024),
      StreamRefSettings(ConfigFactory.defaultReference().getConfig("pekko.stream.materializer.stream-ref")),
      ConfigFactory.defaultReference().getString(ActorAttributes.IODispatcher.dispatcher))

  // backwards compatibility when added IOSettings, shouldn't be needed since private, but added to satisfy mima
  @deprecated("Use ActorMaterializerSettings.apply or ActorMaterializerSettings.create instead", "Akka 2.5.10")
  def this(
      initialInputBufferSize: Int,
      maxInputBufferSize: Int,
      dispatcher: String,
      supervisionDecider: Supervision.Decider,
      subscriptionTimeoutSettings: StreamSubscriptionTimeoutSettings,
      debugLogging: Boolean,
      outputBurstLimit: Int,
      fuzzingMode: Boolean,
      autoFusing: Boolean,
      maxFixedBufferSize: Int) =
    // using config like this is not quite right but the only way to solve backwards comp without hard coding settings
    this(
      initialInputBufferSize,
      maxInputBufferSize,
      dispatcher,
      supervisionDecider,
      subscriptionTimeoutSettings,
      debugLogging,
      outputBurstLimit,
      fuzzingMode,
      autoFusing,
      maxFixedBufferSize,
      1000,
      IOSettings(tcpWriteBufferSize = 16 * 1024),
      StreamRefSettings(ConfigFactory.defaultReference().getConfig("pekko.stream.materializer.stream-ref")),
      ConfigFactory.defaultReference().getString(ActorAttributes.IODispatcher.dispatcher))

  private def copy(
      initialInputBufferSize: Int = this.initialInputBufferSize,
      maxInputBufferSize: Int = this.maxInputBufferSize,
      dispatcher: String = this.dispatcher,
      supervisionDecider: Supervision.Decider = this.supervisionDecider,
      subscriptionTimeoutSettings: StreamSubscriptionTimeoutSettings = this.subscriptionTimeoutSettings,
      debugLogging: Boolean = this.debugLogging,
      outputBurstLimit: Int = this.outputBurstLimit,
      fuzzingMode: Boolean = this.fuzzingMode,
      autoFusing: Boolean = this.autoFusing,
      maxFixedBufferSize: Int = this.maxFixedBufferSize,
      syncProcessingLimit: Int = this.syncProcessingLimit,
      ioSettings: IOSettings = this.ioSettings,
      streamRefSettings: StreamRefSettings = this.streamRefSettings,
      blockingIoDispatcher: String = this.blockingIoDispatcher) = {
    new ActorMaterializerSettings(
      initialInputBufferSize,
      maxInputBufferSize,
      dispatcher,
      supervisionDecider,
      subscriptionTimeoutSettings,
      debugLogging,
      outputBurstLimit,
      fuzzingMode,
      autoFusing,
      maxFixedBufferSize,
      syncProcessingLimit,
      ioSettings,
      streamRefSettings,
      blockingIoDispatcher)
  }

  /**
   * Each asynchronous piece of a materialized stream topology is executed by one Actor
   * that manages an input buffer for all inlets of its shape. This setting configures
   * the default for initial and maximal input buffer in number of elements for each inlet.
   * This can be overridden for individual parts of the
   * stream topology by using [[pekko.stream.Attributes#inputBuffer]].
   *
   * FIXME: this is used for all kinds of buffers, not only the stream actor, some use initial some use max,
   *        document and or fix if it should not be like that. Search for get[Attributes.InputBuffer] to see how it is used
   */
  @deprecated("Use attribute 'Attributes.InputBuffer' to change setting value", "Akka 2.6.0")
  def withInputBuffer(initialSize: Int, maxSize: Int): ActorMaterializerSettings = {
    if (initialSize == this.initialInputBufferSize && maxSize == this.maxInputBufferSize) this
    else copy(initialInputBufferSize = initialSize, maxInputBufferSize = maxSize)
  }

  /**
   * This setting configures the default dispatcher to be used by streams materialized
   * with the [[ActorMaterializer]]. This can be overridden for individual parts of the
   * stream topology by using [[pekko.stream.Attributes#dispatcher]].
   */
  @deprecated("Use attribute 'ActorAttributes.Dispatcher' to change setting value", "Akka 2.6.0")
  def withDispatcher(dispatcher: String): ActorMaterializerSettings = {
    if (this.dispatcher == dispatcher) this
    else copy(dispatcher = dispatcher)
  }

  /**
   * Scala API: Decides how exceptions from application code are to be handled, unless
   * overridden for specific flows of the stream operations with
   * [[pekko.stream.Attributes#supervisionStrategy]].
   *
   * Note that supervision in streams are implemented on a per operator basis and is not supported
   * by every operator.
   */
  @deprecated("Use attribute 'ActorAttributes.supervisionStrategy' to change setting value", "Akka 2.6.0")
  def withSupervisionStrategy(decider: Supervision.Decider): ActorMaterializerSettings = {
    if (decider eq this.supervisionDecider) this
    else copy(supervisionDecider = decider)
  }

  /**
   * Java API: Decides how exceptions from application code are to be handled, unless
   * overridden for specific flows of the stream operations with
   * [[pekko.stream.Attributes#supervisionStrategy]].
   *
   * Note that supervision in streams are implemented on a per operator basis and is not supported
   * by every operator.
   */
  @deprecated("Use attribute 'ActorAttributes.SupervisionStrategy' to change setting value", "Akka 2.6.0")
  def withSupervisionStrategy(
      decider: function.Function[Throwable, Supervision.Directive]): ActorMaterializerSettings = {
    import Supervision._
    copy(supervisionDecider = decider match {
      case `resumingDecider`   => resumingDecider
      case `restartingDecider` => restartingDecider
      case `stoppingDecider`   => stoppingDecider
      case other               => other.apply _
    })
  }

  /**
   * Test utility: fuzzing mode means that GraphStage events are not processed
   * in FIFO order within a fused subgraph, but randomized.
   */
  @deprecated("Use attribute 'ActorAttributes.FuzzingMode' to change setting value", "Akka 2.6.0")
  def withFuzzing(enable: Boolean): ActorMaterializerSettings =
    if (enable == this.fuzzingMode) this
    else copy(fuzzingMode = enable)

  /**
   * Maximum number of elements emitted in batch if downstream signals large demand.
   */
  @deprecated("Use attribute 'ActorAttributes.OutputBurstLimit' to change setting value", "Akka 2.6.0")
  def withOutputBurstLimit(limit: Int): ActorMaterializerSettings =
    if (limit == this.outputBurstLimit) this
    else copy(outputBurstLimit = limit)

  /**
   * Limit for number of messages that can be processed synchronously in stream to substream communication
   */
  @deprecated("Use attribute 'ActorAttributes.SyncProcessingLimit' to change setting value", "Akka 2.6.0")
  def withSyncProcessingLimit(limit: Int): ActorMaterializerSettings =
    if (limit == this.syncProcessingLimit) this
    else copy(syncProcessingLimit = limit)

  /**
   * Enable to log all elements that are dropped due to failures (at DEBUG level).
   */
  @deprecated("Use attribute 'ActorAttributes.DebugLogging' to change setting value", "Akka 2.6.0")
  def withDebugLogging(enable: Boolean): ActorMaterializerSettings =
    if (enable == this.debugLogging) this
    else copy(debugLogging = enable)

  /**
   * Configure the maximum buffer size for which a FixedSizeBuffer will be preallocated.
   * This defaults to a large value because it is usually better to fail early when
   * system memory is not sufficient to hold the buffer.
   */
  @deprecated("Use attribute 'ActorAttributes.MaxFixedBufferSize' to change setting value", "Akka 2.6.0")
  def withMaxFixedBufferSize(size: Int): ActorMaterializerSettings =
    if (size == this.maxFixedBufferSize) this
    else copy(maxFixedBufferSize = size)

  /**
   * Leaked publishers and subscribers are cleaned up when they are not used within a given
   * deadline, configured by [[StreamSubscriptionTimeoutSettings]].
   */
  def withSubscriptionTimeoutSettings(settings: StreamSubscriptionTimeoutSettings): ActorMaterializerSettings =
    if (settings == this.subscriptionTimeoutSettings) this
    else copy(subscriptionTimeoutSettings = settings)

  def withIOSettings(ioSettings: IOSettings): ActorMaterializerSettings =
    if (ioSettings == this.ioSettings) this
    else copy(ioSettings = ioSettings)

  /** Change settings specific to [[SourceRef]] and [[SinkRef]]. */
  def withStreamRefSettings(streamRefSettings: StreamRefSettings): ActorMaterializerSettings =
    if (streamRefSettings == this.streamRefSettings) this
    else copy(streamRefSettings = streamRefSettings)

  @deprecated("Use attribute 'ActorAttributes.BlockingIoDispatcher' to change setting value", "Akka 2.6.0")
  def withBlockingIoDispatcher(newBlockingIoDispatcher: String): ActorMaterializerSettings =
    if (newBlockingIoDispatcher == blockingIoDispatcher) this
    else copy(blockingIoDispatcher = newBlockingIoDispatcher)

  private def requirePowerOfTwo(n: Integer, name: String): Unit = {
    require(n > 0, s"$name must be > 0")
    require((n & (n - 1)) == 0, s"$name must be a power of two")
  }

  override def equals(other: Any): Boolean = other match {
    case s: ActorMaterializerSettings =>
      s.initialInputBufferSize == initialInputBufferSize &&
      s.maxInputBufferSize == maxInputBufferSize &&
      s.dispatcher == dispatcher &&
      s.supervisionDecider == supervisionDecider &&
      s.subscriptionTimeoutSettings == subscriptionTimeoutSettings &&
      s.debugLogging == debugLogging &&
      s.outputBurstLimit == outputBurstLimit &&
      s.syncProcessingLimit == syncProcessingLimit &&
      s.fuzzingMode == fuzzingMode &&
      s.autoFusing == autoFusing &&
      s.ioSettings == ioSettings &&
      s.blockingIoDispatcher == blockingIoDispatcher
    case _ => false
  }

  /**
   * INTERNAL API
   */
  @InternalApi
  private[pekko] def toAttributes: Attributes =
    Attributes(
      // these are the core stream/materializer settings, ad hoc handling of defaults for the stage specific ones
      // for stream refs and io live with the respective stages
      Attributes.InputBuffer(initialInputBufferSize, maxInputBufferSize) ::
      Attributes.CancellationStrategy.Default :: // FIXME: make configurable, see https://github.com/akka/akka/issues/28000
      Attributes.NestedMaterializationCancellationPolicy.Default ::
      ActorAttributes.Dispatcher(dispatcher) ::
      ActorAttributes.SupervisionStrategy(supervisionDecider) ::
      ActorAttributes.DebugLogging(debugLogging) ::
      ActorAttributes
        .StreamSubscriptionTimeout(subscriptionTimeoutSettings.timeout, subscriptionTimeoutSettings.mode) ::
      ActorAttributes.OutputBurstLimit(outputBurstLimit) ::
      ActorAttributes.FuzzingMode(fuzzingMode) ::
      ActorAttributes.MaxFixedBufferSize(maxFixedBufferSize) ::
      ActorAttributes.SyncProcessingLimit(syncProcessingLimit) ::

      Nil)

  override def toString: String =
    s"ActorMaterializerSettings($initialInputBufferSize,$maxInputBufferSize," +
    s"$dispatcher,$supervisionDecider,$subscriptionTimeoutSettings,$debugLogging,$outputBurstLimit," +
    s"$syncProcessingLimit,$fuzzingMode,$autoFusing,$ioSettings)"
}

object IOSettings {
  @deprecated(
    "Use setting 'pekko.stream.materializer.io.tcp.write-buffer-size' or attribute TcpAttributes.writeBufferSize instead",
    "Akka 2.6.0")
  def apply(system: ActorSystem): IOSettings =
    apply(system.settings.config.getConfig("pekko.stream.materializer.io"))

  @deprecated(
    "Use setting 'pekko.stream.materializer.io.tcp.write-buffer-size' or attribute TcpAttributes.writeBufferSize instead",
    "Akka 2.6.0")
  def apply(config: Config): IOSettings =
    new IOSettings(
      tcpWriteBufferSize = math.min(Int.MaxValue, config.getBytes("tcp.write-buffer-size")).toInt,
      coalesceWrites = config.getInt("tcp.coalesce-writes"))

  @deprecated(
    "Use setting 'pekko.stream.materializer.io.tcp.write-buffer-size' or attribute TcpAttributes.writeBufferSize instead",
    "Akka 2.6.0")
  def apply(tcpWriteBufferSize: Int): IOSettings =
    new IOSettings(tcpWriteBufferSize)

  /** Java API */
  @deprecated(
    "Use setting 'pekko.stream.materializer.io.tcp.write-buffer-size' or attribute TcpAttributes.writeBufferSize instead",
    "Akka 2.6.0")
  def create(config: Config) = apply(config)

  /** Java API */
  @deprecated(
    "Use setting 'pekko.stream.materializer.io.tcp.write-buffer-size' or attribute TcpAttributes.writeBufferSize instead",
    "Akka 2.6.0")
  def create(system: ActorSystem) = apply(system)

  /** Java API */
  @deprecated(
    "Use setting 'pekko.stream.materializer.io.tcp.write-buffer-size' or attribute TcpAttributes.writeBufferSize instead",
    "Akka 2.6.0")
  def create(tcpWriteBufferSize: Int): IOSettings =
    apply(tcpWriteBufferSize)
}

@nowarn("msg=deprecated")
final class IOSettings private (
    @deprecated("Use attribute 'TcpAttributes.TcpWriteBufferSize' to read the concrete setting value", "Akka 2.6.0")
    val tcpWriteBufferSize: Int,
    val coalesceWrites: Int) {

  // constructor for binary compatibility with version 2.6.15 and earlier
  @deprecated("Use attribute 'TcpAttributes.TcpWriteBufferSize' to read the concrete setting value", "Akka 2.6.0")
  def this(tcpWriteBufferSize: Int) = this(tcpWriteBufferSize, coalesceWrites = 10)

  def withTcpWriteBufferSize(value: Int): IOSettings = copy(tcpWriteBufferSize = value)

  def withCoalesceWrites(value: Int): IOSettings = copy(coalesceWrites = value)

  private def copy(tcpWriteBufferSize: Int = tcpWriteBufferSize, coalesceWrites: Int = coalesceWrites): IOSettings =
    new IOSettings(tcpWriteBufferSize, coalesceWrites)

  override def equals(other: Any): Boolean = other match {
    case s: IOSettings => s.tcpWriteBufferSize == tcpWriteBufferSize && s.coalesceWrites == coalesceWrites
    case _             => false
  }

  override def hashCode(): Int =
    31 * tcpWriteBufferSize + coalesceWrites

  override def toString =
    s"""IoSettings($tcpWriteBufferSize,$coalesceWrites)"""
}

object StreamSubscriptionTimeoutSettings {
  import pekko.stream.StreamSubscriptionTimeoutTerminationMode._

  /**
   * Create settings from individual values (Java).
   */
  def create(
      mode: StreamSubscriptionTimeoutTerminationMode,
      timeout: FiniteDuration): StreamSubscriptionTimeoutSettings =
    new StreamSubscriptionTimeoutSettings(mode, timeout)

  /**
   * Create settings from individual values (Scala).
   */
  def apply(
      mode: StreamSubscriptionTimeoutTerminationMode,
      timeout: FiniteDuration): StreamSubscriptionTimeoutSettings =
    new StreamSubscriptionTimeoutSettings(mode, timeout)

  /**
   * Create settings from a Config subsection (Java).
   */
  def create(config: Config): StreamSubscriptionTimeoutSettings =
    apply(config)

  /**
   * Create settings from a Config subsection (Scala).
   */
  def apply(config: Config): StreamSubscriptionTimeoutSettings = {
    val c = config.getConfig("subscription-timeout")
    StreamSubscriptionTimeoutSettings(
      mode = toRootLowerCase(c.getString("mode")) match {
        case "no" | "off" | "false" | "noop" => NoopTermination
        case "warn"                          => WarnTermination
        case "cancel"                        => CancelTermination
      }, timeout = c.getDuration("timeout", TimeUnit.MILLISECONDS).millis)
  }
}

/**
 * Leaked publishers and subscribers are cleaned up when they are not used within a given
 * deadline, configured by [[StreamSubscriptionTimeoutSettings]].
 */
@nowarn("msg=deprecated")
final class StreamSubscriptionTimeoutSettings(
    @deprecated(
      "Use attribute 'ActorAttributes.StreamSubscriptionTimeoutMode' to read the concrete setting value",
      "Akka 2.6.0")
    val mode: StreamSubscriptionTimeoutTerminationMode,
    @deprecated("Use attribute 'ActorAttributes.StreamSubscriptionTimeout' to read the concrete setting value",
      "Akka 2.6.0")
    val timeout: FiniteDuration) {
  override def equals(other: Any): Boolean = other match {
    case s: StreamSubscriptionTimeoutSettings => s.mode == mode && s.timeout == timeout
    case _                                    => false
  }
  override def toString: String = s"StreamSubscriptionTimeoutSettings($mode,$timeout)"
}

/**
 * This mode describes what shall happen when the subscription timeout expires for
 * substream Publishers created by operations like `prefixAndTail`.
 */
sealed abstract class StreamSubscriptionTimeoutTerminationMode

object StreamSubscriptionTimeoutTerminationMode {
  case object NoopTermination extends StreamSubscriptionTimeoutTerminationMode
  case object WarnTermination extends StreamSubscriptionTimeoutTerminationMode
  case object CancelTermination extends StreamSubscriptionTimeoutTerminationMode

  /**
   * Do not do anything when timeout expires.
   */
  def noop: StreamSubscriptionTimeoutTerminationMode = NoopTermination

  /**
   * Log a warning when the timeout expires.
   */
  def warn: StreamSubscriptionTimeoutTerminationMode = WarnTermination

  /**
   * When the timeout expires attach a Subscriber that will immediately cancel its subscription.
   */
  def cancel: StreamSubscriptionTimeoutTerminationMode = CancelTermination

}
