/*
 * 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.fn.data;

import static org.hamcrest.Matchers.contains;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;

import java.util.ArrayList;
import java.util.Collection;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.apache.beam.model.fnexecution.v1.BeamFnApi;
import org.apache.beam.model.pipeline.v1.Endpoints;
import org.apache.beam.sdk.fn.stream.OutboundObserverFactory;
import org.apache.beam.sdk.fn.test.TestStreams;
import org.apache.beam.vendor.grpc.v1p21p0.com.google.protobuf.ByteString;
import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.util.concurrent.Uninterruptibles;
import org.junit.Test;

/** Tests for {@link BeamFnDataGrpcMultiplexer}. */
public class BeamFnDataGrpcMultiplexerTest {
  private static final Endpoints.ApiServiceDescriptor DESCRIPTOR =
      Endpoints.ApiServiceDescriptor.newBuilder().setUrl("test").build();
  private static final LogicalEndpoint OUTPUT_LOCATION = LogicalEndpoint.of("777L", "888L");
  private static final BeamFnApi.Elements ELEMENTS =
      BeamFnApi.Elements.newBuilder()
          .addData(
              BeamFnApi.Elements.Data.newBuilder()
                  .setInstructionId(OUTPUT_LOCATION.getInstructionId())
                  .setTransformId(OUTPUT_LOCATION.getTransformId())
                  .setData(ByteString.copyFrom(new byte[1])))
          .build();
  private static final BeamFnApi.Elements TERMINAL_ELEMENTS =
      BeamFnApi.Elements.newBuilder()
          .addData(
              BeamFnApi.Elements.Data.newBuilder()
                  .setInstructionId(OUTPUT_LOCATION.getInstructionId())
                  .setTransformId(OUTPUT_LOCATION.getTransformId()))
          .build();

  @Test
  public void testOutboundObserver() {
    final Collection<BeamFnApi.Elements> values = new ArrayList<>();
    BeamFnDataGrpcMultiplexer multiplexer =
        new BeamFnDataGrpcMultiplexer(
            DESCRIPTOR,
            OutboundObserverFactory.clientDirect(),
            inboundObserver -> TestStreams.withOnNext(values::add).build());
    multiplexer.getOutboundObserver().onNext(ELEMENTS);
    assertThat(values, contains(ELEMENTS));
  }

  @Test
  public void testInboundObserverBlocksTillConsumerConnects() throws Exception {
    final Collection<BeamFnApi.Elements> outboundValues = new ArrayList<>();
    final Collection<BeamFnApi.Elements.Data> inboundValues = new ArrayList<>();
    final BeamFnDataGrpcMultiplexer multiplexer =
        new BeamFnDataGrpcMultiplexer(
            DESCRIPTOR,
            OutboundObserverFactory.clientDirect(),
            inboundObserver -> TestStreams.withOnNext(outboundValues::add).build());
    ExecutorService executorService = Executors.newCachedThreadPool();
    executorService
        .submit(
            () -> {
              // Purposefully sleep to simulate a delay in a consumer connecting.
              Uninterruptibles.sleepUninterruptibly(100, TimeUnit.MILLISECONDS);
              multiplexer.registerConsumer(OUTPUT_LOCATION, inboundValues::add);
            })
        .get();
    multiplexer.getInboundObserver().onNext(ELEMENTS);
    assertTrue(multiplexer.hasConsumer(OUTPUT_LOCATION));
    // Ensure that when we see a terminal Elements object, we remove the consumer
    multiplexer.getInboundObserver().onNext(TERMINAL_ELEMENTS);
    assertFalse(multiplexer.hasConsumer(OUTPUT_LOCATION));

    // Assert that normal and terminal Elements are passed to the consumer
    assertThat(inboundValues, contains(ELEMENTS.getData(0), TERMINAL_ELEMENTS.getData(0)));
  }
}