/*
 * 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.beam.sdk.io.gcp.pubsublite;

import static org.apache.beam.sdk.util.Preconditions.checkArgumentNotNull;

import com.google.cloud.pubsublite.AdminClient;
import com.google.cloud.pubsublite.AdminClientSettings;
import com.google.cloud.pubsublite.BacklogLocation;
import com.google.cloud.pubsublite.CloudZone;
import com.google.cloud.pubsublite.Message;
import com.google.cloud.pubsublite.ProjectId;
import com.google.cloud.pubsublite.SubscriptionName;
import com.google.cloud.pubsublite.SubscriptionPath;
import com.google.cloud.pubsublite.TopicName;
import com.google.cloud.pubsublite.TopicPath;
import com.google.cloud.pubsublite.proto.PubSubMessage;
import com.google.cloud.pubsublite.proto.SequencedMessage;
import com.google.cloud.pubsublite.proto.Subscription;
import com.google.cloud.pubsublite.proto.Subscription.DeliveryConfig.DeliveryRequirement;
import com.google.cloud.pubsublite.proto.Topic;
import com.google.cloud.pubsublite.proto.Topic.PartitionConfig.Capacity;
import com.google.protobuf.ByteString;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Set;
import java.util.concurrent.ThreadLocalRandom;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.PipelineResult;
import org.apache.beam.sdk.coders.BigEndianIntegerCoder;
import org.apache.beam.sdk.extensions.gcp.options.GcpOptions;
import org.apache.beam.sdk.io.gcp.pubsub.TestPubsubSignal;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.StreamingOptions;
import org.apache.beam.sdk.testing.TestPipeline;
import org.apache.beam.sdk.testing.TestPipelineOptions;
import org.apache.beam.sdk.transforms.Create;
import org.apache.beam.sdk.transforms.FlatMapElements;
import org.apache.beam.sdk.transforms.MapElements;
import org.apache.beam.sdk.transforms.PTransform;
import org.apache.beam.sdk.transforms.SerializableFunction;
import org.apache.beam.sdk.transforms.SimpleFunction;
import org.apache.beam.sdk.values.PCollection;
import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Supplier;
import org.joda.time.Duration;
import org.junit.After;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@RunWith(JUnit4.class)
public class ReadWriteIT {
  private static final Logger LOG = LoggerFactory.getLogger(ReadWriteIT.class);
  private static final CloudZone ZONE = CloudZone.parse("us-central1-b");
  private static final int MESSAGE_COUNT = 90;

  @Rule public transient TestPubsubSignal signal = TestPubsubSignal.create();
  @Rule public transient TestPipeline pipeline = TestPipeline.create();

  private static ProjectId getProject(PipelineOptions options) {
    return ProjectId.of(checkArgumentNotNull(options.as(GcpOptions.class).getProject()));
  }

  private static String randomName() {
    return "beam_it_resource_" + ThreadLocalRandom.current().nextLong();
  }

  private static AdminClient newAdminClient() {
    return AdminClient.create(AdminClientSettings.newBuilder().setRegion(ZONE.region()).build());
  }

  private final Deque<Runnable> cleanupActions = new ArrayDeque<>();

  private TopicPath createTopic(ProjectId id) throws Exception {
    TopicPath toReturn =
        TopicPath.newBuilder()
            .setProject(id)
            .setLocation(ZONE)
            .setName(TopicName.of(randomName()))
            .build();
    Topic.Builder topic = Topic.newBuilder().setName(toReturn.toString());
    topic
        .getPartitionConfigBuilder()
        .setCount(2)
        .setCapacity(Capacity.newBuilder().setPublishMibPerSec(4).setSubscribeMibPerSec(4));
    topic.getRetentionConfigBuilder().setPerPartitionBytes(30 * (1L << 30));
    cleanupActions.addLast(
        () -> {
          try (AdminClient client = newAdminClient()) {
            client.deleteTopic(toReturn).get();
          } catch (Throwable t) {
            LOG.error("Failed to clean up topic.", t);
          }
        });
    try (AdminClient client = newAdminClient()) {
      client.createTopic(topic.build()).get();
    }
    return toReturn;
  }

  private SubscriptionPath createSubscription(TopicPath topic) throws Exception {
    SubscriptionPath toReturn =
        SubscriptionPath.newBuilder()
            .setProject(topic.project())
            .setLocation(ZONE)
            .setName(SubscriptionName.of(randomName()))
            .build();
    Subscription.Builder subscription = Subscription.newBuilder().setName(toReturn.toString());
    subscription
        .getDeliveryConfigBuilder()
        .setDeliveryRequirement(DeliveryRequirement.DELIVER_IMMEDIATELY);
    subscription.setTopic(topic.toString());
    cleanupActions.addLast(
        () -> {
          try (AdminClient client = newAdminClient()) {
            client.deleteSubscription(toReturn).get();
          } catch (Throwable t) {
            LOG.error("Failed to clean up subscription.", t);
          }
        });
    try (AdminClient client = newAdminClient()) {
      client.createSubscription(subscription.build(), BacklogLocation.BEGINNING).get();
    }
    return toReturn;
  }

  @After
  public void tearDown() {
    while (!cleanupActions.isEmpty()) {
      cleanupActions.removeLast().run();
    }
  }

  // Workaround for https://github.com/apache/beam/issues/21257
  // TODO(https://github.com/apache/beam/issues/21257): Remove this.
  private static class CustomCreate extends PTransform<PCollection<Void>, PCollection<Integer>> {
    @Override
    public PCollection<Integer> expand(PCollection<Void> input) {
      return input.apply(
          "createIndexes",
          FlatMapElements.via(
              new SimpleFunction<Void, Iterable<Integer>>() {
                @Override
                public Iterable<Integer> apply(Void input) {
                  return IntStream.range(0, MESSAGE_COUNT).boxed().collect(Collectors.toList());
                }
              }));
    }
  }

  public static void writeMessages(TopicPath topicPath, Pipeline pipeline) {
    PCollection<Void> trigger = pipeline.apply(Create.of((Void) null));
    PCollection<Integer> indexes = trigger.apply("createIndexes", new CustomCreate());
    PCollection<PubSubMessage> messages =
        indexes.apply(
            "createMessages",
            MapElements.via(
                new SimpleFunction<Integer, PubSubMessage>(
                    index ->
                        Message.builder()
                            .setData(ByteString.copyFromUtf8(index.toString()))
                            .build()
                            .toProto()) {}));
    // Add UUIDs to messages for later deduplication.
    messages = messages.apply("addUuids", PubsubLiteIO.addUuids());
    messages.apply(
        "writeMessages",
        PubsubLiteIO.write(PublisherOptions.newBuilder().setTopicPath(topicPath).build()));
  }

  public static PCollection<SequencedMessage> readMessages(
      SubscriptionPath subscriptionPath, Pipeline pipeline) {
    PCollection<SequencedMessage> messages =
        pipeline.apply(
            "readMessages",
            PubsubLiteIO.read(
                SubscriberOptions.newBuilder().setSubscriptionPath(subscriptionPath).build()));
    return messages;
    // TODO(https://github.com/apache/beam/issues/21157): Fix and re-enable
    // Deduplicate messages based on the uuids added in PubsubLiteIO.addUuids() when writing.
    // return messages.apply(
    //   "dedupeMessages", PubsubLiteIO.deduplicate(UuidDeduplicationOptions.newBuilder().build()));
  }

  public static SimpleFunction<SequencedMessage, Integer> extractIds() {
    return new SimpleFunction<SequencedMessage, Integer>() {
      @Override
      public Integer apply(SequencedMessage input) {
        return Integer.parseInt(input.getMessage().getData().toStringUtf8());
      }
    };
  }

  public static SerializableFunction<Set<Integer>, Boolean> testIds() {
    return ids -> {
      LOG.info("Ids are: {}", ids);
      Set<Integer> target = IntStream.range(0, MESSAGE_COUNT).boxed().collect(Collectors.toSet());
      return target.equals(ids);
    };
  }

  @Test
  public void testReadWrite() throws Exception {
    pipeline.getOptions().as(StreamingOptions.class).setStreaming(true);
    pipeline.getOptions().as(TestPipelineOptions.class).setBlockOnRun(false);

    TopicPath topic = createTopic(getProject(pipeline.getOptions()));
    SubscriptionPath subscription = null;
    Exception lastException = null;
    for (int i = 0; i < 30; ++i) {
      // Sleep for topic creation to propagate.
      Thread.sleep(1000);
      try {
        subscription = createSubscription(topic);
        break;
      } catch (Exception e) {
        lastException = e;
        LOG.info("Retrying exception on subscription creation.", e);
      }
    }
    if (subscription == null) {
      throw lastException;
    }

    // Publish some messages
    writeMessages(topic, pipeline);

    // Read some messages. They should be deduplicated by the time we see them, so there should be
    // exactly numMessages, one for every index in [0,MESSAGE_COUNT).
    PCollection<SequencedMessage> messages = readMessages(subscription, pipeline);
    PCollection<Integer> ids = messages.apply(MapElements.via(extractIds()));
    ids.apply("PubsubSignalTest", signal.signalSuccessWhen(BigEndianIntegerCoder.of(), testIds()));
    Supplier<Void> start = signal.waitForStart(Duration.standardMinutes(5));
    pipeline.apply(signal.signalStart());
    PipelineResult job = pipeline.run();
    start.get();
    LOG.info("Running!");
    signal.waitForSuccess(Duration.standardMinutes(5));
    // A runner may not support cancel
    try {
      job.cancel();
    } catch (UnsupportedOperationException exc) {
      // noop
    }
  }
}
