/*
 * Copyright (C) 2009-2021 Lightbend Inc. <https://www.lightbend.com>
 */

package akka.cluster.ddata.protobuf

import java.io.NotSerializableException
import java.util.concurrent.TimeUnit
import java.util.concurrent.atomic.AtomicInteger

import scala.annotation.tailrec
import scala.collection.immutable
import scala.concurrent.duration._
import scala.concurrent.duration.Duration
import scala.concurrent.duration.FiniteDuration

import akka.actor.Address
import akka.actor.ExtendedActorSystem
import akka.annotation.InternalApi
import akka.cluster.Member
import akka.cluster.UniqueAddress
import akka.cluster.ddata.DurableStore.DurableDataEnvelope
import akka.cluster.ddata.Key.KeyR
import akka.cluster.ddata.PruningState
import akka.cluster.ddata.PruningState.PruningPerformed
import akka.cluster.ddata.ReplicatedData
import akka.cluster.ddata.Replicator._
import akka.cluster.ddata.Replicator.Internal._
import akka.cluster.ddata.VersionVector
import akka.cluster.ddata.protobuf.msg.{ ReplicatorMessages => dm }
import akka.protobufv3.internal.ByteString
import akka.serialization.BaseSerializer
import akka.serialization.Serialization
import akka.serialization.SerializerWithStringManifest
import akka.util.{ ByteString => AkkaByteString }
import akka.util.ccompat._
import akka.util.ccompat.JavaConverters._

/**
 * INTERNAL API
 */
@ccompatUsedUntil213
@InternalApi
private[akka] object ReplicatorMessageSerializer {

  /**
   * A cache that is designed for a small number (&lt;= 32) of
   * entries. It is using instance equality.
   * Adding new entry overwrites oldest. It is
   * thread safe but duplicates of same entry may occur.
   *
   * `evict` must be called from the outside, i.e. the
   * cache will not cleanup itself.
   */
  final class SmallCache[A <: AnyRef, B <: AnyRef](size: Int, timeToLive: FiniteDuration, getOrAddFactory: A => B) {
    require((size & (size - 1)) == 0, "size must be a power of 2")
    require(size <= 32, "size must be <= 32")

    private val n = new AtomicInteger(0)
    private val mask = size - 1
    private val elements = new Array[(A, B)](size)
    private val ttlNanos = timeToLive.toNanos

    // in theory this should be volatile, but since the cache has low
    // guarantees anyway and visibility will be synced by other activity
    // so we use non-volatile
    private var lastUsed = System.nanoTime()

    /**
     * Get value from cache or `null` if it doesn't exist.
     */
    def get(a: A): B = get(a, n.get)

    private def get(a: A, startPos: Int): B = {
      // start at the latest added value, most likely that we want that
      val end = startPos + elements.length
      @tailrec def find(i: Int): B = {
        if (end - i == 0) null.asInstanceOf[B]
        else {
          val x = elements(i & mask)
          if ((x eq null) || (x._1 ne a)) find(i + 1)
          else x._2
        }
      }
      lastUsed = System.nanoTime()
      find(startPos)
    }

    /**
     * Add entry to the cache.
     * Overwrites oldest entry.
     */
    def add(a: A, b: B): Unit = add((a, b))

    def add(x: (A, B)): Unit = {
      val i = n.incrementAndGet()
      elements(i & mask) = x
      lastUsed = System.nanoTime()
    }

    /**
     * Get value from cache or create new value with the
     * `getOrAddFactory` that was given in the constructor. The new
     * value is added to the cache. Duplicates of same value may be added
     * if multiple threads call this concurrently, but decent
     * (low cost) effort is made to reduce the chance of duplicates.
     */
    def getOrAdd(a: A): B = {
      val position = n.get
      val c = get(a, position)
      if (c ne null)
        c
      else {
        val b2 = getOrAddFactory(a)
        if (position == n.get) {
          // no change, add the new value
          add(a, b2)
          b2
        } else {
          // some other thread added, try one more time
          // to reduce duplicates
          val c2 = get(a)
          if (c2 ne null) c2 // found it
          else {
            add(a, b2)
            b2
          }
        }
      }
    }

    /**
     * Remove all elements if the cache has not been
     * used within the `timeToLive`.
     */
    def evict(): Unit =
      if ((System.nanoTime() - lastUsed) > ttlNanos) {
        var i = 0
        while (i < elements.length) {
          elements(i) = null
          i += 1
        }
      }

    override def toString: String =
      elements.mkString("[", ",", "]")
  }
}

/**
 * Protobuf serializer of ReplicatorMessage messages.
 */
class ReplicatorMessageSerializer(val system: ExtendedActorSystem)
    extends SerializerWithStringManifest
    with SerializationSupport
    with BaseSerializer {
  import ReplicatorMessageSerializer.SmallCache

  private val cacheTimeToLive = system.settings.config
    .getDuration("akka.cluster.distributed-data.serializer-cache-time-to-live", TimeUnit.MILLISECONDS)
    .millis
  private val readCache = new SmallCache[Read, Array[Byte]](4, cacheTimeToLive, m => readToProto(m).toByteArray)
  private val writeCache = new SmallCache[Write, Array[Byte]](4, cacheTimeToLive, m => writeToProto(m).toByteArray)
  system.scheduler.scheduleWithFixedDelay(cacheTimeToLive, cacheTimeToLive / 2) { () =>
    readCache.evict()
    writeCache.evict()
  }(system.dispatchers.internalDispatcher)

  private val writeAckBytes = dm.Empty.getDefaultInstance.toByteArray
  private val dummyAddress = UniqueAddress(Address("a", "b", "c", 2552), 1L)

  val GetManifest = "A"
  val GetSuccessManifest = "B"
  val NotFoundManifest = "C"
  val GetFailureManifest = "D"
  val SubscribeManifest = "E"
  val UnsubscribeManifest = "F"
  val ChangedManifest = "G"
  val DataEnvelopeManifest = "H"
  val WriteManifest = "I"
  val WriteAckManifest = "J"
  val ReadManifest = "K"
  val ReadResultManifest = "L"
  val StatusManifest = "M"
  val GossipManifest = "N"
  val WriteNackManifest = "O"
  val DurableDataEnvelopeManifest = "P"
  val DeltaPropagationManifest = "Q"
  val DeltaNackManifest = "R"

  private val fromBinaryMap = collection.immutable.HashMap[String, Array[Byte] => AnyRef](
    GetManifest -> getFromBinary,
    GetSuccessManifest -> getSuccessFromBinary,
    NotFoundManifest -> notFoundFromBinary,
    GetFailureManifest -> getFailureFromBinary,
    SubscribeManifest -> subscribeFromBinary,
    UnsubscribeManifest -> unsubscribeFromBinary,
    ChangedManifest -> changedFromBinary,
    DataEnvelopeManifest -> dataEnvelopeFromBinary,
    WriteManifest -> writeFromBinary,
    WriteAckManifest -> (_ => WriteAck),
    ReadManifest -> readFromBinary,
    ReadResultManifest -> readResultFromBinary,
    StatusManifest -> statusFromBinary,
    GossipManifest -> gossipFromBinary,
    DeltaPropagationManifest -> deltaPropagationFromBinary,
    WriteNackManifest -> (_ => WriteNack),
    DeltaNackManifest -> (_ => DeltaNack),
    DurableDataEnvelopeManifest -> durableDataEnvelopeFromBinary)

  override def manifest(obj: AnyRef): String = obj match {
    case _: DataEnvelope        => DataEnvelopeManifest
    case _: Write               => WriteManifest
    case WriteAck               => WriteAckManifest
    case _: Read                => ReadManifest
    case _: ReadResult          => ReadResultManifest
    case _: DeltaPropagation    => DeltaPropagationManifest
    case _: Status              => StatusManifest
    case _: Get[_]              => GetManifest
    case _: GetSuccess[_]       => GetSuccessManifest
    case _: DurableDataEnvelope => DurableDataEnvelopeManifest
    case _: Changed[_]          => ChangedManifest
    case _: NotFound[_]         => NotFoundManifest
    case _: GetFailure[_]       => GetFailureManifest
    case _: Subscribe[_]        => SubscribeManifest
    case _: Unsubscribe[_]      => UnsubscribeManifest
    case _: Gossip              => GossipManifest
    case WriteNack              => WriteNackManifest
    case DeltaNack              => DeltaNackManifest
    case _ =>
      throw new IllegalArgumentException(s"Can't serialize object of type ${obj.getClass} in [${getClass.getName}]")
  }

  def toBinary(obj: AnyRef): Array[Byte] = obj match {
    case m: DataEnvelope        => dataEnvelopeToProto(m).toByteArray
    case m: Write               => writeCache.getOrAdd(m)
    case WriteAck               => writeAckBytes
    case m: Read                => readCache.getOrAdd(m)
    case m: ReadResult          => readResultToProto(m).toByteArray
    case m: Status              => statusToProto(m).toByteArray
    case m: DeltaPropagation    => deltaPropagationToProto(m).toByteArray
    case m: Get[_]              => getToProto(m).toByteArray
    case m: GetSuccess[_]       => getSuccessToProto(m).toByteArray
    case m: DurableDataEnvelope => durableDataEnvelopeToProto(m).toByteArray
    case m: Changed[_]          => changedToProto(m).toByteArray
    case m: NotFound[_]         => notFoundToProto(m).toByteArray
    case m: GetFailure[_]       => getFailureToProto(m).toByteArray
    case m: Subscribe[_]        => subscribeToProto(m).toByteArray
    case m: Unsubscribe[_]      => unsubscribeToProto(m).toByteArray
    case m: Gossip              => compress(gossipToProto(m))
    case WriteNack              => dm.Empty.getDefaultInstance.toByteArray
    case DeltaNack              => dm.Empty.getDefaultInstance.toByteArray
    case _ =>
      throw new IllegalArgumentException(s"Can't serialize object of type ${obj.getClass} in [${getClass.getName}]")
  }

  override def fromBinary(bytes: Array[Byte], manifest: String): AnyRef =
    fromBinaryMap.get(manifest) match {
      case Some(f) => f(bytes)
      case None =>
        throw new NotSerializableException(
          s"Unimplemented deserialization of message with manifest [$manifest] in [${getClass.getName}]")
    }

  private def statusToProto(status: Status): dm.Status = {
    val b = dm.Status.newBuilder()
    b.setChunk(status.chunk).setTotChunks(status.totChunks)
    status.digests.foreach {
      case (key, digest) =>
        b.addEntries(dm.Status.Entry.newBuilder().setKey(key).setDigest(ByteString.copyFrom(digest.toArray)))
    }
    status.toSystemUid.foreach(b.setToSystemUid) // can be None when sending back to a node of version 2.5.21
    b.setFromSystemUid(status.fromSystemUid.get)
    b.build()
  }

  private def statusFromBinary(bytes: Array[Byte]): Status = {
    val status = dm.Status.parseFrom(bytes)
    val toSystemUid = if (status.hasToSystemUid) Some(status.getToSystemUid) else None
    val fromSystemUid = if (status.hasFromSystemUid) Some(status.getFromSystemUid) else None
    Status(
      status.getEntriesList.asScala.iterator.map(e => e.getKey -> AkkaByteString(e.getDigest.toByteArray())).toMap,
      status.getChunk,
      status.getTotChunks,
      toSystemUid,
      fromSystemUid)
  }

  private def gossipToProto(gossip: Gossip): dm.Gossip = {
    val b = dm.Gossip.newBuilder().setSendBack(gossip.sendBack)
    gossip.updatedData.foreach {
      case (key, data) =>
        b.addEntries(dm.Gossip.Entry.newBuilder().setKey(key).setEnvelope(dataEnvelopeToProto(data)))
    }
    gossip.toSystemUid.foreach(b.setToSystemUid) // can be None when sending back to a node of version 2.5.21
    b.setFromSystemUid(gossip.fromSystemUid.get)
    b.build()
  }

  private def gossipFromBinary(bytes: Array[Byte]): Gossip = {
    val gossip = dm.Gossip.parseFrom(decompress(bytes))
    val toSystemUid = if (gossip.hasToSystemUid) Some(gossip.getToSystemUid) else None
    val fromSystemUid = if (gossip.hasFromSystemUid) Some(gossip.getFromSystemUid) else None
    Gossip(
      gossip.getEntriesList.asScala.iterator.map(e => e.getKey -> dataEnvelopeFromProto(e.getEnvelope)).toMap,
      sendBack = gossip.getSendBack,
      toSystemUid,
      fromSystemUid)
  }

  private def deltaPropagationToProto(deltaPropagation: DeltaPropagation): dm.DeltaPropagation = {
    val b = dm.DeltaPropagation.newBuilder().setFromNode(uniqueAddressToProto(deltaPropagation._fromNode))
    if (deltaPropagation.reply)
      b.setReply(deltaPropagation.reply)
    deltaPropagation.deltas.foreach {
      case (key, Delta(data, fromSeqNr, toSeqNr)) =>
        val b2 = dm.DeltaPropagation.Entry
          .newBuilder()
          .setKey(key)
          .setEnvelope(dataEnvelopeToProto(data))
          .setFromSeqNr(fromSeqNr)
        if (toSeqNr != fromSeqNr)
          b2.setToSeqNr(toSeqNr)
        b.addEntries(b2)
    }
    b.build()
  }

  private def deltaPropagationFromBinary(bytes: Array[Byte]): DeltaPropagation = {
    val deltaPropagation = dm.DeltaPropagation.parseFrom(bytes)
    val reply = deltaPropagation.hasReply && deltaPropagation.getReply
    DeltaPropagation(
      uniqueAddressFromProto(deltaPropagation.getFromNode),
      reply,
      deltaPropagation.getEntriesList.asScala.iterator.map { e =>
        val fromSeqNr = e.getFromSeqNr
        val toSeqNr = if (e.hasToSeqNr) e.getToSeqNr else fromSeqNr
        e.getKey -> Delta(dataEnvelopeFromProto(e.getEnvelope), fromSeqNr, toSeqNr)
      }.toMap)
  }

  private def getToProto(get: Get[_]): dm.Get = {
    val timoutInMillis = get.consistency.timeout.toMillis
    require(timoutInMillis <= 0XFFFFFFFFL, "Timeouts must fit in a 32-bit unsigned int")

    val b = dm.Get.newBuilder().setKey(otherMessageToProto(get.key)).setTimeout(timoutInMillis.toInt)

    get.consistency match {
      case ReadLocal      => b.setConsistency(1)
      case ReadFrom(n, _) => b.setConsistency(n)
      case ReadMajority(_, minCap) =>
        b.setConsistency(0)
        if (minCap != 0)
          b.setConsistencyMinCap(minCap)
      case ReadMajorityPlus(_, additional, minCap) =>
        b.setConsistency(0)
        if (minCap != 0)
          b.setConsistencyMinCap(minCap)
        if (additional != 0)
          b.setConsistencyAdditional(additional)
      case _: ReadAll =>
        b.setConsistency(-1)
    }

    get.request.foreach(o => b.setRequest(otherMessageToProto(o)))
    b.build()
  }

  private def getFromBinary(bytes: Array[Byte]): Get[_] = {
    val get = dm.Get.parseFrom(bytes)
    val key = otherMessageFromProto(get.getKey).asInstanceOf[KeyR]
    val request = if (get.hasRequest()) Some(otherMessageFromProto(get.getRequest)) else None
    // 32-bit unsigned protobuf integers are mapped to
    // 32-bit signed Java ints, using the leftmost bit as sign.
    val timeout =
      if (get.getTimeout < 0) Duration(Int.MaxValue.toLong + (get.getTimeout - Int.MaxValue), TimeUnit.MILLISECONDS)
      else Duration(get.getTimeout.toLong, TimeUnit.MILLISECONDS)
    def minCap = if (get.hasConsistencyMinCap) get.getConsistencyMinCap else 0
    val consistency = get.getConsistency match {
      case 0 =>
        if (get.hasConsistencyAdditional)
          ReadMajorityPlus(timeout, get.getConsistencyAdditional, minCap)
        else
          ReadMajority(timeout, minCap)
      case -1 => ReadAll(timeout)
      case 1  => ReadLocal
      case n  => ReadFrom(n, timeout)
    }
    Get(key, consistency, request)
  }

  private def getSuccessToProto(getSuccess: GetSuccess[_]): dm.GetSuccess = {
    val b = dm.GetSuccess
      .newBuilder()
      .setKey(otherMessageToProto(getSuccess.key))
      .setData(otherMessageToProto(getSuccess.dataValue))

    getSuccess.request.foreach(o => b.setRequest(otherMessageToProto(o)))
    b.build()
  }

  private def getSuccessFromBinary(bytes: Array[Byte]): GetSuccess[_] = {
    val getSuccess = dm.GetSuccess.parseFrom(bytes)
    val key = otherMessageFromProto(getSuccess.getKey).asInstanceOf[KeyR]
    val request = if (getSuccess.hasRequest()) Some(otherMessageFromProto(getSuccess.getRequest)) else None
    val data = otherMessageFromProto(getSuccess.getData).asInstanceOf[ReplicatedData]
    GetSuccess(key, request)(data)
  }

  private def notFoundToProto(notFound: NotFound[_]): dm.NotFound = {
    val b = dm.NotFound.newBuilder().setKey(otherMessageToProto(notFound.key))
    notFound.request.foreach(o => b.setRequest(otherMessageToProto(o)))
    b.build()
  }

  private def notFoundFromBinary(bytes: Array[Byte]): NotFound[_] = {
    val notFound = dm.NotFound.parseFrom(bytes)
    val request = if (notFound.hasRequest()) Some(otherMessageFromProto(notFound.getRequest)) else None
    val key = otherMessageFromProto(notFound.getKey).asInstanceOf[KeyR]
    NotFound(key, request)
  }

  private def getFailureToProto(getFailure: GetFailure[_]): dm.GetFailure = {
    val b = dm.GetFailure.newBuilder().setKey(otherMessageToProto(getFailure.key))
    getFailure.request.foreach(o => b.setRequest(otherMessageToProto(o)))
    b.build()
  }

  private def getFailureFromBinary(bytes: Array[Byte]): GetFailure[_] = {
    val getFailure = dm.GetFailure.parseFrom(bytes)
    val request = if (getFailure.hasRequest()) Some(otherMessageFromProto(getFailure.getRequest)) else None
    val key = otherMessageFromProto(getFailure.getKey).asInstanceOf[KeyR]
    GetFailure(key, request)
  }

  private def subscribeToProto(subscribe: Subscribe[_]): dm.Subscribe =
    dm.Subscribe
      .newBuilder()
      .setKey(otherMessageToProto(subscribe.key))
      .setRef(Serialization.serializedActorPath(subscribe.subscriber))
      .build()

  private def subscribeFromBinary(bytes: Array[Byte]): Subscribe[_] = {
    val subscribe = dm.Subscribe.parseFrom(bytes)
    val key = otherMessageFromProto(subscribe.getKey).asInstanceOf[KeyR]
    Subscribe(key, resolveActorRef(subscribe.getRef))
  }

  private def unsubscribeToProto(unsubscribe: Unsubscribe[_]): dm.Unsubscribe =
    dm.Unsubscribe
      .newBuilder()
      .setKey(otherMessageToProto(unsubscribe.key))
      .setRef(Serialization.serializedActorPath(unsubscribe.subscriber))
      .build()

  private def unsubscribeFromBinary(bytes: Array[Byte]): Unsubscribe[_] = {
    val unsubscribe = dm.Unsubscribe.parseFrom(bytes)
    val key = otherMessageFromProto(unsubscribe.getKey).asInstanceOf[KeyR]
    Unsubscribe(key, resolveActorRef(unsubscribe.getRef))
  }

  private def changedToProto(changed: Changed[_]): dm.Changed =
    dm.Changed
      .newBuilder()
      .setKey(otherMessageToProto(changed.key))
      .setData(otherMessageToProto(changed.dataValue))
      .build()

  private def changedFromBinary(bytes: Array[Byte]): Changed[_] = {
    val changed = dm.Changed.parseFrom(bytes)
    val data = otherMessageFromProto(changed.getData).asInstanceOf[ReplicatedData]
    val key = otherMessageFromProto(changed.getKey).asInstanceOf[KeyR]
    Changed(key)(data)
  }

  private def pruningToProto(entries: Map[UniqueAddress, PruningState]): Iterable[dm.DataEnvelope.PruningEntry] = {
    entries.map {
      case (removedAddress, state) =>
        val b = dm.DataEnvelope.PruningEntry.newBuilder().setRemovedAddress(uniqueAddressToProto(removedAddress))
        state match {
          case PruningState.PruningInitialized(owner, seen) =>
            seen.toVector.sorted(Member.addressOrdering).map(addressToProto).foreach { a =>
              b.addSeen(a)
            }
            b.setOwnerAddress(uniqueAddressToProto(owner))
            b.setPerformed(false)
          case PruningState.PruningPerformed(obsoleteTime) =>
            b.setPerformed(true).setObsoleteTime(obsoleteTime)
            // TODO ownerAddress is only needed for PruningInitialized, but kept here for
            // wire backwards compatibility with 2.4.16 (required field)
            b.setOwnerAddress(uniqueAddressToProto(dummyAddress))
        }
        b.build()
    }
  }

  private def dataEnvelopeToProto(dataEnvelope: DataEnvelope): dm.DataEnvelope = {
    val dataEnvelopeBuilder = dm.DataEnvelope.newBuilder().setData(otherMessageToProto(dataEnvelope.data))

    dataEnvelopeBuilder.addAllPruning(pruningToProto(dataEnvelope.pruning).asJava)

    if (!dataEnvelope.deltaVersions.isEmpty)
      dataEnvelopeBuilder.setDeltaVersions(versionVectorToProto(dataEnvelope.deltaVersions))

    dataEnvelopeBuilder.build()
  }

  private def dataEnvelopeFromBinary(bytes: Array[Byte]): DataEnvelope =
    dataEnvelopeFromProto(dm.DataEnvelope.parseFrom(bytes))

  private def dataEnvelopeFromProto(dataEnvelope: dm.DataEnvelope): DataEnvelope = {
    val data = otherMessageFromProto(dataEnvelope.getData).asInstanceOf[ReplicatedData]
    val pruning = pruningFromProto(dataEnvelope.getPruningList)
    val deltaVersions =
      if (dataEnvelope.hasDeltaVersions) versionVectorFromProto(dataEnvelope.getDeltaVersions)
      else VersionVector.empty
    DataEnvelope(data, pruning, deltaVersions)
  }

  private def pruningFromProto(
      pruningEntries: java.util.List[dm.DataEnvelope.PruningEntry]): Map[UniqueAddress, PruningState] = {
    if (pruningEntries.isEmpty)
      Map.empty
    else
      pruningEntries.asScala.iterator.map { pruningEntry =>
        val state =
          if (pruningEntry.getPerformed) {
            // for wire compatibility with Akka 2.4.x
            val obsoleteTime = if (pruningEntry.hasObsoleteTime) pruningEntry.getObsoleteTime else Long.MaxValue
            PruningState.PruningPerformed(obsoleteTime)
          } else
            PruningState.PruningInitialized(
              uniqueAddressFromProto(pruningEntry.getOwnerAddress),
              pruningEntry.getSeenList.asScala.iterator.map(addressFromProto).to(immutable.Set))
        val removed = uniqueAddressFromProto(pruningEntry.getRemovedAddress)
        removed -> state
      }.toMap
  }

  private def writeToProto(write: Write): dm.Write =
    dm.Write
      .newBuilder()
      .setKey(write.key)
      .setEnvelope(dataEnvelopeToProto(write.envelope))
      .setFromNode(uniqueAddressToProto(write.fromNode.get))
      .build()

  private def writeFromBinary(bytes: Array[Byte]): Write = {
    val write = dm.Write.parseFrom(bytes)
    val fromNode = if (write.hasFromNode) Some(uniqueAddressFromProto(write.getFromNode)) else None
    Write(write.getKey, dataEnvelopeFromProto(write.getEnvelope), fromNode)
  }

  private def readToProto(read: Read): dm.Read =
    dm.Read.newBuilder().setKey(read.key).setFromNode(uniqueAddressToProto(read.fromNode.get)).build()

  private def readFromBinary(bytes: Array[Byte]): Read = {
    val read = dm.Read.parseFrom(bytes)
    val fromNode = if (read.hasFromNode) Some(uniqueAddressFromProto(read.getFromNode)) else None
    Read(read.getKey, fromNode)
  }

  private def readResultToProto(readResult: ReadResult): dm.ReadResult = {
    val b = dm.ReadResult.newBuilder()
    readResult.envelope match {
      case Some(d) => b.setEnvelope(dataEnvelopeToProto(d))
      case None    =>
    }
    b.build()
  }

  private def readResultFromBinary(bytes: Array[Byte]): ReadResult = {
    val readResult = dm.ReadResult.parseFrom(bytes)
    val envelope =
      if (readResult.hasEnvelope) Some(dataEnvelopeFromProto(readResult.getEnvelope))
      else None
    ReadResult(envelope)
  }

  private def durableDataEnvelopeToProto(durableDataEnvelope: DurableDataEnvelope): dm.DurableDataEnvelope = {
    // only keep the PruningPerformed entries
    val pruning = durableDataEnvelope.dataEnvelope.pruning.filter {
      case (_, _: PruningPerformed) => true
      case _                        => false
    }

    val builder = dm.DurableDataEnvelope.newBuilder().setData(otherMessageToProto(durableDataEnvelope.data))

    builder.addAllPruning(pruningToProto(pruning).asJava)

    builder.build()
  }

  private def durableDataEnvelopeFromBinary(bytes: Array[Byte]): DurableDataEnvelope =
    durableDataEnvelopeFromProto(dm.DurableDataEnvelope.parseFrom(bytes))

  private def durableDataEnvelopeFromProto(durableDataEnvelope: dm.DurableDataEnvelope): DurableDataEnvelope = {
    val data = otherMessageFromProto(durableDataEnvelope.getData).asInstanceOf[ReplicatedData]
    val pruning = pruningFromProto(durableDataEnvelope.getPruningList)

    new DurableDataEnvelope(DataEnvelope(data, pruning))
  }

}
