content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.kafka.raft;
  
  import org.apache.kafka.common.Uuid;
  import org.apache.kafka.common.network.ListenerName;
  import org.apache.kafka.common.utils.LogContext;
  import org.apache.kafka.common.utils.MockTime;
  
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.CsvSource;
  import org.junit.jupiter.params.provider.ValueSource;
  
  import java.net.InetSocketAddress;
  import java.util.Map;
  import java.util.Optional;
  import java.util.OptionalInt;
  import java.util.Set;
  import java.util.stream.IntStream;
  import java.util.stream.Stream;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  public class ProspectiveStateTest {
      private final ReplicaKey localReplicaKey = ReplicaKey.of(0, Uuid.randomUuid());
      private final Endpoints leaderEndpoints = Endpoints.fromInetSocketAddresses(
          Map.of(
              ListenerName.normalised("CONTROLLER"),
              InetSocketAddress.createUnresolved("mock-host-3", 1234)
          )
      );
      private final int epoch = 5;
      private final MockTime time = new MockTime();
      private final int electionTimeoutMs = 10000;
      private final LogContext logContext = new LogContext();
      private final int localId = 0;
      private final int votedId = 1;
      private final Uuid votedDirectoryId = Uuid.randomUuid();
      private final ReplicaKey votedKeyWithDirectoryId = ReplicaKey.of(votedId, votedDirectoryId);
      private final ReplicaKey votedKeyWithoutDirectoryId = ReplicaKey.of(votedId, ReplicaKey.NO_DIRECTORY_ID);
  
      private ProspectiveState newProspectiveState(
          VoterSet voters,
          OptionalInt leaderId,
          Optional<ReplicaKey> votedKey
      ) {
          return new ProspectiveState(
              time,
              localReplicaKey.id(),
              epoch,
              leaderId,
              leaderId.isPresent() ? leaderEndpoints : Endpoints.empty(),
              votedKey,
              voters,
              Optional.empty(),
              electionTimeoutMs,
              logContext
          );
      }
  
      private ProspectiveState newProspectiveState(VoterSet voters) {
          return new ProspectiveState(
              time,
              localReplicaKey.id(),
              epoch,
              OptionalInt.empty(),
              Endpoints.empty(),
              Optional.empty(),
              voters,
              Optional.empty(),
              electionTimeoutMs,
              logContext
          );
      }
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testSingleNodeQuorum(boolean withDirectoryId) {
          ProspectiveState state = newProspectiveState(voterSetWithLocal(IntStream.empty(), withDirectoryId));
          assertTrue(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
          assertEquals(Set.of(), state.epochElection().unrecordedVoters());
      }
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testTwoNodeQuorumVoteRejected(boolean withDirectoryId) {
          ReplicaKey otherNode = replicaKey(1, withDirectoryId);
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(Stream.of(otherNode), withDirectoryId)
          );
          assertFalse(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
          assertEquals(Set.of(otherNode), state.epochElection().unrecordedVoters());
          assertTrue(state.recordRejectedVote(otherNode.id()));
          assertFalse(state.epochElection().isVoteGranted());
          assertTrue(state.epochElection().isVoteRejected());
      }
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testTwoNodeQuorumVoteGranted(boolean withDirectoryId) {
          ReplicaKey otherNode = replicaKey(1, withDirectoryId);
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(Stream.of(otherNode), withDirectoryId)
          );
          assertFalse(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
          assertEquals(Set.of(otherNode), state.epochElection().unrecordedVoters());
          assertTrue(state.recordGrantedVote(otherNode.id()));
          assertEquals(Set.of(), state.epochElection().unrecordedVoters());
          assertFalse(state.epochElection().isVoteRejected());
          assertTrue(state.epochElection().isVoteGranted());
      }
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testThreeNodeQuorumVoteGranted(boolean withDirectoryId) {
          ReplicaKey node1 = replicaKey(1, withDirectoryId);
          ReplicaKey node2 = replicaKey(2, withDirectoryId);
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(Stream.of(node1, node2), withDirectoryId)
          );
          assertFalse(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
          assertEquals(Set.of(node1, node2), state.epochElection().unrecordedVoters());
          assertTrue(state.recordGrantedVote(node1.id()));
          assertEquals(Set.of(node2), state.epochElection().unrecordedVoters());
          assertTrue(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
          assertTrue(state.recordRejectedVote(node2.id()));
          assertEquals(Set.of(), state.epochElection().unrecordedVoters());
          assertTrue(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
      }
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testThreeNodeQuorumVoteRejected(boolean withDirectoryId) {
          ReplicaKey node1 = replicaKey(1, withDirectoryId);
          ReplicaKey node2 = replicaKey(2, withDirectoryId);
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(Stream.of(node1, node2), withDirectoryId)
          );
          assertFalse(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
          assertEquals(Set.of(node1, node2), state.epochElection().unrecordedVoters());
          assertTrue(state.recordRejectedVote(node1.id()));
          assertEquals(Set.of(node2), state.epochElection().unrecordedVoters());
          assertFalse(state.epochElection().isVoteGranted());
          assertFalse(state.epochElection().isVoteRejected());
          assertTrue(state.recordRejectedVote(node2.id()));
          assertEquals(Set.of(), state.epochElection().unrecordedVoters());
          assertFalse(state.epochElection().isVoteGranted());
          assertTrue(state.epochElection().isVoteRejected());
      }
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testCanChangePreVote(boolean withDirectoryId) {
          int voter1 = 1;
          int voter2 = 2;
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(IntStream.of(voter1, voter2), withDirectoryId)
          );
          assertTrue(state.recordGrantedVote(voter1));
          assertTrue(state.epochElection().isVoteGranted());
          assertFalse(state.recordRejectedVote(voter1));
          assertFalse(state.epochElection().isVoteGranted());
  
          assertTrue(state.recordRejectedVote(voter2));
          assertTrue(state.epochElection().isVoteRejected());
          assertFalse(state.recordGrantedVote(voter2));
          assertFalse(state.epochElection().isVoteRejected());
      }
  
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testCannotGrantOrRejectNonVoters(boolean withDirectoryId) {
          int nonVoterId = 1;
          ProspectiveState state = newProspectiveState(voterSetWithLocal(IntStream.empty(), withDirectoryId));
          assertThrows(IllegalArgumentException.class, () -> state.recordGrantedVote(nonVoterId));
          assertThrows(IllegalArgumentException.class, () -> state.recordRejectedVote(nonVoterId));
      }
  
      @ParameterizedTest
      @ValueSource(booleans = { true, false })
      public void testConsecutiveGrant(boolean withDirectoryId) {
          int otherNodeId = 1;
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(IntStream.of(otherNodeId), withDirectoryId)
          );
          assertTrue(state.recordGrantedVote(otherNodeId));
          assertFalse(state.recordGrantedVote(otherNodeId));
      }
  
      @ParameterizedTest
      @ValueSource(booleans = {true, false})
      public void testConsecutiveReject(boolean withDirectoryId) {
          int otherNodeId = 1;
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(IntStream.of(otherNodeId), withDirectoryId)
          );
          assertTrue(state.recordRejectedVote(otherNodeId));
          assertFalse(state.recordRejectedVote(otherNodeId));
      }
  
      @ParameterizedTest
      @CsvSource({ "true,true", "true,false", "false,true", "false,false" })
      public void testGrantVote(boolean isLogUpToDate, boolean withDirectoryId) {
          ReplicaKey node0 = replicaKey(0, withDirectoryId);
          ReplicaKey node1 = replicaKey(1, withDirectoryId);
          ReplicaKey node2 = replicaKey(2, withDirectoryId);
  
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(Stream.of(node1, node2), withDirectoryId)
          );
  
          assertEquals(isLogUpToDate, state.canGrantVote(node0, isLogUpToDate, true));
          assertEquals(isLogUpToDate, state.canGrantVote(node1, isLogUpToDate, true));
          assertEquals(isLogUpToDate, state.canGrantVote(node2, isLogUpToDate, true));
  
          assertEquals(isLogUpToDate, state.canGrantVote(node0, isLogUpToDate, false));
          assertEquals(isLogUpToDate, state.canGrantVote(node1, isLogUpToDate, false));
          assertEquals(isLogUpToDate, state.canGrantVote(node2, isLogUpToDate, false));
      }
  
      @ParameterizedTest
      @CsvSource({ "true,true", "true,false", "false,true", "false,false" })
      public void testGrantVoteWithVotedKey(boolean isLogUpToDate, boolean withDirectoryId) {
          ReplicaKey node0 = replicaKey(0, withDirectoryId);
          ReplicaKey node1 = replicaKey(1, withDirectoryId);
          ReplicaKey node2 = replicaKey(2, withDirectoryId);
  
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(Stream.of(node1, node2), withDirectoryId),
              OptionalInt.empty(),
              Optional.of(node1)
          );
  
          assertEquals(isLogUpToDate, state.canGrantVote(node0, isLogUpToDate, true));
          assertEquals(isLogUpToDate, state.canGrantVote(node1, isLogUpToDate, true));
          assertEquals(isLogUpToDate, state.canGrantVote(node2, isLogUpToDate, true));
  
          assertFalse(state.canGrantVote(node0, isLogUpToDate, false));
          assertTrue(state.canGrantVote(node1, isLogUpToDate, false));
          assertFalse(state.canGrantVote(node2, isLogUpToDate, false));
      }
  
      @ParameterizedTest
      @CsvSource({ "true,true", "true,false", "false,true", "false,false" })
      public void testGrantVoteWithLeader(boolean isLogUpToDate, boolean withDirectoryId) {
          ReplicaKey node0 = replicaKey(0, withDirectoryId);
          ReplicaKey node1 = replicaKey(1, withDirectoryId);
          ReplicaKey node2 = replicaKey(2, withDirectoryId);
  
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(Stream.of(node1, node2), withDirectoryId),
              OptionalInt.of(node1.id()),
              Optional.empty()
          );
  
          assertEquals(isLogUpToDate, state.canGrantVote(node0, isLogUpToDate, true));
          assertEquals(isLogUpToDate, state.canGrantVote(node1, isLogUpToDate, true));
          assertEquals(isLogUpToDate, state.canGrantVote(node2, isLogUpToDate, true));
  
          assertFalse(state.canGrantVote(node0, isLogUpToDate, false));
          assertFalse(state.canGrantVote(node1, isLogUpToDate, false));
          assertFalse(state.canGrantVote(node2, isLogUpToDate, false));
      }
  
      @ParameterizedTest
      @ValueSource(booleans = {true, false})
      public void testElectionState(boolean withDirectoryId) {
          VoterSet voters = voterSetWithLocal(IntStream.of(1, 2, 3), withDirectoryId);
          ProspectiveState state = newProspectiveState(voters);
          assertEquals(
              ElectionState.withUnknownLeader(
                  epoch,
                  voters.voterIds()
              ),
              state.election()
          );
  
          // with leader
          state = newProspectiveState(voters, OptionalInt.of(1), Optional.empty());
          assertEquals(
              ElectionState.withElectedLeader(
                  epoch,
                  1,
                  Optional.empty(), voters.voterIds()
              ),
              state.election()
          );
  
          // with voted key
          ReplicaKey votedKey = replicaKey(1, withDirectoryId);
          state = newProspectiveState(voters, OptionalInt.empty(), Optional.of(votedKey));
          assertEquals(
              ElectionState.withVotedCandidate(
                  epoch,
                  votedKey,
                  voters.voterIds()
              ),
              state.election()
          );
  
          // with both
          state = newProspectiveState(voters, OptionalInt.of(1), Optional.of(votedKey));
          assertEquals(
              ElectionState.withElectedLeader(
                  epoch,
                  1,
                  Optional.of(votedKey),
                  voters.voterIds()
              ),
              state.election()
          );
      }
  
      @Test
      public void testElectionTimeout() {
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(IntStream.empty(), true),
              OptionalInt.empty(),
              Optional.of(votedKeyWithDirectoryId)
          );
  
          assertEquals(epoch, state.epoch());
          assertEquals(votedKeyWithDirectoryId, state.votedKey().get());
          assertEquals(
              ElectionState.withVotedCandidate(epoch, votedKeyWithDirectoryId, Set.of(localId)),
              state.election()
          );
          assertEquals(electionTimeoutMs, state.remainingElectionTimeMs(time.milliseconds()));
          assertFalse(state.hasElectionTimeoutExpired(time.milliseconds()));
  
          time.sleep(5000);
          assertEquals(electionTimeoutMs - 5000, state.remainingElectionTimeMs(time.milliseconds()));
          assertFalse(state.hasElectionTimeoutExpired(time.milliseconds()));
  
          time.sleep(5000);
          assertEquals(0, state.remainingElectionTimeMs(time.milliseconds()));
          assertTrue(state.hasElectionTimeoutExpired(time.milliseconds()));
      }
  
      @ParameterizedTest
      @ValueSource(booleans = {true, false})
      public void testCanGrantVoteWithoutDirectoryId(boolean isLogUpToDate) {
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(IntStream.empty(), true),
              OptionalInt.empty(),
              Optional.of(votedKeyWithoutDirectoryId));
  
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(ReplicaKey.of(votedId, ReplicaKey.NO_DIRECTORY_ID), isLogUpToDate, true)
          );
          assertTrue(state.canGrantVote(ReplicaKey.of(votedId, ReplicaKey.NO_DIRECTORY_ID), isLogUpToDate, false));
  
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(ReplicaKey.of(votedId, Uuid.randomUuid()), isLogUpToDate, true)
          );
          assertTrue(state.canGrantVote(ReplicaKey.of(votedId, Uuid.randomUuid()), isLogUpToDate, false));
  
          // Can grant PreVote to other replicas even if we have granted a standard vote to another replica
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(ReplicaKey.of(votedId + 1, ReplicaKey.NO_DIRECTORY_ID), isLogUpToDate, true)
          );
          assertFalse(state.canGrantVote(ReplicaKey.of(votedId + 1, ReplicaKey.NO_DIRECTORY_ID), isLogUpToDate, false));
      }
  
      @ParameterizedTest
      @ValueSource(booleans = {true, false})
      void testCanGrantVoteWithDirectoryId(boolean isLogUpToDate) {
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(IntStream.empty(), true),
              OptionalInt.empty(),
              Optional.of(votedKeyWithDirectoryId));
  
          // Same voterKey
          // We will not grant PreVote for a replica we have already granted a standard vote to if their log is behind
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(votedKeyWithDirectoryId, isLogUpToDate, true)
          );
          assertTrue(state.canGrantVote(votedKeyWithDirectoryId, isLogUpToDate, false));
  
          // Different directoryId
          // We can grant PreVote for a replica we have already granted a standard vote to if their log is up-to-date,
          // even if the directoryId is different
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(ReplicaKey.of(votedId, Uuid.randomUuid()), isLogUpToDate, true)
          );
          assertFalse(state.canGrantVote(ReplicaKey.of(votedId, Uuid.randomUuid()), isLogUpToDate, false));
  
          // Missing directoryId
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(ReplicaKey.of(votedId, ReplicaKey.NO_DIRECTORY_ID), isLogUpToDate, true)
          );
          assertFalse(state.canGrantVote(ReplicaKey.of(votedId, ReplicaKey.NO_DIRECTORY_ID), isLogUpToDate, false));
  
          // Different voterId
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(ReplicaKey.of(votedId + 1, votedDirectoryId), isLogUpToDate, true)
          );
          assertEquals(
              isLogUpToDate,
              state.canGrantVote(ReplicaKey.of(votedId + 1, ReplicaKey.NO_DIRECTORY_ID), isLogUpToDate, true)
          );
          assertFalse(state.canGrantVote(ReplicaKey.of(votedId + 1, votedDirectoryId), true, false));
          assertFalse(state.canGrantVote(ReplicaKey.of(votedId + 1, ReplicaKey.NO_DIRECTORY_ID), true, false));
      }
  
      @Test
      public void testLeaderEndpoints() {
          ProspectiveState state = newProspectiveState(
              voterSetWithLocal(IntStream.of(1, 2, 3), true),
              OptionalInt.empty(),
              Optional.of(ReplicaKey.of(1, Uuid.randomUuid()))
          );
          assertEquals(Endpoints.empty(), state.leaderEndpoints());
  
          state = newProspectiveState(
              voterSetWithLocal(IntStream.of(1, 2, 3), true),
              OptionalInt.of(3),
              Optional.of(ReplicaKey.of(1, Uuid.randomUuid()))
          );
          assertEquals(leaderEndpoints, state.leaderEndpoints());
      }
  
      private ReplicaKey replicaKey(int id, boolean withDirectoryId) {
          Uuid directoryId = withDirectoryId ? Uuid.randomUuid() : ReplicaKey.NO_DIRECTORY_ID;
          return ReplicaKey.of(id, directoryId);
      }
  
      private VoterSet voterSetWithLocal(IntStream remoteVoterIds, boolean withDirectoryId) {
          Stream<ReplicaKey> remoteVoterKeys = remoteVoterIds
              .boxed()
              .map(id -> replicaKey(id, withDirectoryId));
  
          return voterSetWithLocal(remoteVoterKeys, withDirectoryId);
      }
  
      private VoterSet voterSetWithLocal(Stream<ReplicaKey> remoteVoterKeys, boolean withDirectoryId) {
          ReplicaKey actualLocalVoter = withDirectoryId ?
              localReplicaKey :
              ReplicaKey.of(localReplicaKey.id(), ReplicaKey.NO_DIRECTORY_ID);
  
          return VoterSetTest.voterSet(
              Stream.concat(Stream.of(actualLocalVoter), remoteVoterKeys)
          );
      }
  }
  