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.coordinator.group.streams.topics;
  
  import org.apache.kafka.common.errors.StreamsInvalidTopologyException;
  import org.apache.kafka.common.utils.LogContext;
  import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyValue.Subtopology;
  import org.apache.kafka.coordinator.group.generated.StreamsGroupTopologyValue.TopicInfo;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.OptionalInt;
  import java.util.function.Function;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  public class RepartitionTopicsTest {
  
      private static final LogContext LOG_CONTEXT = new LogContext();
      private static final String SOURCE_TOPIC_NAME1 = "source1";
      private static final String SOURCE_TOPIC_NAME2 = "source2";
      private static final TopicInfo REPARTITION_TOPIC1 = new TopicInfo().setName("repartition1").setPartitions(4);
      private static final TopicInfo REPARTITION_TOPIC2 = new TopicInfo().setName("repartition2").setPartitions(2);
      private static final TopicInfo REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT = new TopicInfo().setName("repartitionWithoutPartitionCount");
  
      private static OptionalInt sourceTopicPartitionCounts(final String topicName) {
          return SOURCE_TOPIC_NAME1.equals(topicName) || SOURCE_TOPIC_NAME2.equals(topicName) ? OptionalInt.of(3) : OptionalInt.empty();
      }
  
      @Test
      public void shouldSetupRepartitionTopics() {
          final Subtopology subtopology1 = new Subtopology()
              .setSubtopologyId("subtopology1")
              .setSourceTopics(List.of(SOURCE_TOPIC_NAME1, SOURCE_TOPIC_NAME2))
              .setRepartitionSinkTopics(List.of(REPARTITION_TOPIC1.name()));
          final Subtopology subtopology2 = new Subtopology()
              .setSubtopologyId("subtopology2")
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC1));
          final List<Subtopology> subtopologies = List.of(subtopology1, subtopology2);
          final RepartitionTopics repartitionTopics = new RepartitionTopics(
              LOG_CONTEXT,
              subtopologies,
              RepartitionTopicsTest::sourceTopicPartitionCounts
          );
  
          final Map<String, Integer> setup = repartitionTopics.setup();
  
          assertEquals(
              Map.of(REPARTITION_TOPIC1.name(), REPARTITION_TOPIC1.partitions()),
              setup
          );
      }
  
      @Test
      public void shouldThrowIllegalStateExceptionIfMissingSourceTopics() {
          final Subtopology subtopology1 = new Subtopology()
              .setSubtopologyId("subtopology1")
              .setSourceTopics(List.of(SOURCE_TOPIC_NAME1, SOURCE_TOPIC_NAME2))
              .setRepartitionSinkTopics(List.of(REPARTITION_TOPIC1.name()));
          final Subtopology subtopology2 = new Subtopology()
              .setSubtopologyId("subtopology2")
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC1));
          final Function<String, OptionalInt> topicPartitionCountProvider =
              s -> Objects.equals(s, SOURCE_TOPIC_NAME1) ? OptionalInt.empty() : sourceTopicPartitionCounts(s);
          final RepartitionTopics repartitionTopics = new RepartitionTopics(
              LOG_CONTEXT,
              List.of(subtopology1, subtopology2),
              topicPartitionCountProvider
          );
  
          final IllegalStateException exception = assertThrows(IllegalStateException.class,
              repartitionTopics::setup);
  
          assertEquals("Missing source topics: source1", exception.getMessage());
      }
  
      @Test
      public void shouldThrowStreamsInvalidTopologyExceptionIfPartitionCountCannotBeComputedForAllRepartitionTopicsDueToLoops() {
          final Subtopology subtopology1 = new Subtopology()
              .setSubtopologyId("subtopology1")
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT))
              .setRepartitionSinkTopics(List.of(REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT.name()));
          final RepartitionTopics repartitionTopics = new RepartitionTopics(
              LOG_CONTEXT,
              List.of(subtopology1),
              RepartitionTopicsTest::sourceTopicPartitionCounts
          );
  
          final StreamsInvalidTopologyException exception = assertThrows(StreamsInvalidTopologyException.class, repartitionTopics::setup);
  
          assertEquals(
              "Failed to compute number of partitions for all repartition topics. There may be loops in the topology that cannot be resolved.",
              exception.getMessage()
          );
      }
  
      @Test
      public void shouldThrowStreamsInvalidTopologyExceptionIfPartitionCountCannotBeComputedForAllRepartitionTopicsDueToMissingSinks() {
          final Subtopology subtopology1 = new Subtopology()
              .setSubtopologyId("subtopology1")
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT));
          final RepartitionTopics repartitionTopics = new RepartitionTopics(
              LOG_CONTEXT,
              List.of(subtopology1),
              RepartitionTopicsTest::sourceTopicPartitionCounts
          );
  
          final StreamsInvalidTopologyException exception = assertThrows(StreamsInvalidTopologyException.class, repartitionTopics::setup);
  
          assertEquals(
              "Failed to compute number of partitions for all repartition topics, because a repartition source topic is never used as a sink topic.",
              exception.getMessage()
          );
      }
  
      @Test
      public void shouldSetRepartitionTopicPartitionCountFromUpstreamExternalSourceTopic() {
          final Subtopology subtopology = new Subtopology()
              .setSubtopologyId("subtopology0")
              .setSourceTopics(List.of(SOURCE_TOPIC_NAME1))
              .setRepartitionSinkTopics(List.of(REPARTITION_TOPIC1.name(), REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT.name()))
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC2));
          final Subtopology subtopologyWithoutPartitionCount = new Subtopology()
              .setSubtopologyId("subtopologyWithoutPartitionCount")
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC1, REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT));
          final RepartitionTopics repartitionTopics = new RepartitionTopics(
              LOG_CONTEXT,
              List.of(subtopology, subtopologyWithoutPartitionCount),
              RepartitionTopicsTest::sourceTopicPartitionCounts
          );
  
          final Map<String, Integer> setup = repartitionTopics.setup();
  
          assertEquals(Map.of(
              REPARTITION_TOPIC1.name(), REPARTITION_TOPIC1.partitions(),
              REPARTITION_TOPIC2.name(), REPARTITION_TOPIC2.partitions(),
              REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT.name(), sourceTopicPartitionCounts(SOURCE_TOPIC_NAME1).getAsInt()
          ), setup);
      }
  
      @Test
      public void shouldSetRepartitionTopicPartitionCountFromUpstreamInternalRepartitionSourceTopic() {
          final Subtopology subtopology = new Subtopology()
              .setSubtopologyId("subtopology0")
              .setSourceTopics(List.of(SOURCE_TOPIC_NAME1))
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC1))
              .setRepartitionSinkTopics(List.of(REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT.name()));
          final Subtopology subtopologyWithoutPartitionCount = new Subtopology()
              .setSubtopologyId("subtopologyWithoutPartitionCount")
              .setRepartitionSourceTopics(List.of(REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT))
              .setRepartitionSinkTopics(List.of(REPARTITION_TOPIC1.name()));
          final RepartitionTopics repartitionTopics = new RepartitionTopics(
              LOG_CONTEXT,
              List.of(subtopology, subtopologyWithoutPartitionCount),
              RepartitionTopicsTest::sourceTopicPartitionCounts
          );
  
          final Map<String, Integer> setup = repartitionTopics.setup();
  
          assertEquals(
              Map.of(
                  REPARTITION_TOPIC1.name(), REPARTITION_TOPIC1.partitions(),
                  REPARTITION_TOPIC_WITHOUT_PARTITION_COUNT.name(), REPARTITION_TOPIC1.partitions()
              ),
              setup
          );
      }
  
      @Test
      public void shouldNotSetupRepartitionTopicsWhenTopologyDoesNotContainAnyRepartitionTopics() {
          final Subtopology subtopology = new Subtopology()
              .setSubtopologyId("subtopology0")
              .setSourceTopics(List.of(SOURCE_TOPIC_NAME1));
          final RepartitionTopics repartitionTopics = new RepartitionTopics(
              LOG_CONTEXT,
              List.of(subtopology),
              RepartitionTopicsTest::sourceTopicPartitionCounts
          );
  
          final Map<String, Integer> setup = repartitionTopics.setup();
  
          assertEquals(Map.of(), setup);
      }
  
  }