/*
 * 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.runners.direct.portable;

import static org.apache.beam.vendor.guava.v20_0.com.google.common.base.Preconditions.checkState;
import static org.apache.beam.vendor.guava.v20_0.com.google.common.collect.Iterables.getOnlyElement;
import static org.hamcrest.Matchers.equalTo;
import static org.junit.Assert.assertThat;

import java.io.Serializable;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;
import org.apache.beam.model.pipeline.v1.RunnerApi;
import org.apache.beam.runners.core.construction.PipelineTranslation;
import org.apache.beam.runners.core.construction.graph.ExecutableStage;
import org.apache.beam.runners.core.construction.graph.GreedyPipelineFuser;
import org.apache.beam.runners.core.construction.graph.PipelineNode;
import org.apache.beam.runners.core.construction.graph.PipelineNode.PCollectionNode;
import org.apache.beam.runners.core.construction.graph.PipelineNode.PTransformNode;
import org.apache.beam.runners.core.construction.graph.QueryablePipeline;
import org.apache.beam.runners.fnexecution.GrpcContextHeaderAccessorProvider;
import org.apache.beam.runners.fnexecution.GrpcFnServer;
import org.apache.beam.runners.fnexecution.InProcessServerFactory;
import org.apache.beam.runners.fnexecution.control.FnApiControlClientPoolService;
import org.apache.beam.runners.fnexecution.control.InstructionRequestHandler;
import org.apache.beam.runners.fnexecution.control.JobBundleFactory;
import org.apache.beam.runners.fnexecution.control.SingleEnvironmentInstanceJobBundleFactory;
import org.apache.beam.runners.fnexecution.data.GrpcDataService;
import org.apache.beam.runners.fnexecution.environment.EmbeddedEnvironmentFactory;
import org.apache.beam.runners.fnexecution.environment.EnvironmentFactory;
import org.apache.beam.runners.fnexecution.logging.GrpcLoggingService;
import org.apache.beam.runners.fnexecution.logging.Slf4jLogWriter;
import org.apache.beam.runners.fnexecution.state.GrpcStateService;
import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.fn.IdGenerators;
import org.apache.beam.sdk.fn.stream.OutboundObserverFactory;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.transforms.DoFn;
import org.apache.beam.sdk.transforms.Flatten;
import org.apache.beam.sdk.transforms.GroupByKey;
import org.apache.beam.sdk.transforms.Impulse;
import org.apache.beam.sdk.transforms.ParDo;
import org.apache.beam.sdk.util.WindowedValue;
import org.apache.beam.sdk.values.KV;
import org.apache.beam.sdk.values.PCollection;
import org.apache.beam.sdk.values.PCollectionList;
import org.apache.beam.vendor.guava.v20_0.com.google.common.collect.Iterables;
import org.joda.time.Instant;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link RemoteStageEvaluatorFactory}. */
@RunWith(JUnit4.class)
public class RemoteStageEvaluatorFactoryTest implements Serializable {

  private transient RemoteStageEvaluatorFactory factory;
  private transient ExecutorService executor;
  private transient GrpcFnServer<GrpcDataService> dataServer;
  private transient GrpcFnServer<GrpcStateService> stateServer;
  private transient GrpcFnServer<FnApiControlClientPoolService> controlServer;
  private transient GrpcFnServer<GrpcLoggingService> loggingServer;
  private transient BundleFactory bundleFactory;

  @Before
  public void setup() throws Exception {
    InProcessServerFactory serverFactory = InProcessServerFactory.create();

    BlockingQueue<InstructionRequestHandler> clientPool = new LinkedBlockingQueue<>();
    controlServer =
        GrpcFnServer.allocatePortAndCreateFor(
            FnApiControlClientPoolService.offeringClientsToPool(
                (workerId, instructionHandler) -> clientPool.put(instructionHandler),
                GrpcContextHeaderAccessorProvider.getHeaderAccessor()),
            serverFactory);
    loggingServer =
        GrpcFnServer.allocatePortAndCreateFor(
            GrpcLoggingService.forWriter(Slf4jLogWriter.getDefault()), serverFactory);

    EnvironmentFactory environmentFactory =
        EmbeddedEnvironmentFactory.create(
            PipelineOptionsFactory.create(),
            loggingServer,
            controlServer,
            (workerId, timeout) -> clientPool.take());
    executor = Executors.newCachedThreadPool();
    dataServer =
        GrpcFnServer.allocatePortAndCreateFor(
            GrpcDataService.create(executor, OutboundObserverFactory.serverDirect()),
            serverFactory);
    stateServer = GrpcFnServer.allocatePortAndCreateFor(GrpcStateService.create(), serverFactory);

    bundleFactory = ImmutableListBundleFactory.create();
    JobBundleFactory jobBundleFactory =
        SingleEnvironmentInstanceJobBundleFactory.create(
            environmentFactory, dataServer, stateServer, IdGenerators.incrementingLongs());
    factory = new RemoteStageEvaluatorFactory(bundleFactory, jobBundleFactory);
  }

  @After
  public void teardown() throws Exception {
    try (AutoCloseable logging = loggingServer;
        AutoCloseable exec = executor::shutdownNow;
        AutoCloseable data = dataServer;
        AutoCloseable state = stateServer;
        AutoCloseable control = controlServer) {}
  }

  @Test
  public void executesRemoteStage() throws Exception {
    Pipeline p = Pipeline.create();
    p.apply("impulse", Impulse.create())
        .apply(
            "CreateInputs",
            ParDo.of(
                new DoFn<byte[], Integer>() {
                  @ProcessElement
                  public void create(ProcessContext ctxt) {
                    ctxt.output(1);
                    ctxt.output(2);
                    ctxt.output(3);
                  }
                }))
        .apply(
            "ParDo",
            ParDo.of(
                new DoFn<Integer, KV<String, Long>>() {
                  @ProcessElement
                  public void proc(ProcessContext ctxt) {
                    ctxt.output(KV.of("foo", ctxt.element().longValue()));
                  }
                }))
        .apply(GroupByKey.create());

    RunnerApi.Pipeline fusedPipeline =
        GreedyPipelineFuser.fuse(PipelineTranslation.toProto(p)).toPipeline();
    QueryablePipeline fusedQP = QueryablePipeline.forPipeline(fusedPipeline);
    PTransformNode impulseTransform = getOnlyElement(fusedQP.getRootTransforms());
    PCollectionNode impulseOutput = getOnlyElement(fusedQP.getOutputPCollections(impulseTransform));
    PTransformNode stage =
        fusedPipeline.getRootTransformIdsList().stream()
            .map(
                id ->
                    PipelineNode.pTransform(
                        id, fusedPipeline.getComponents().getTransformsOrThrow(id)))
            .filter(node -> node.getTransform().getSpec().getUrn().equals(ExecutableStage.URN))
            .findFirst()
            .orElseThrow(IllegalArgumentException::new);

    WindowedValue<byte[]> impulse = WindowedValue.valueInGlobalWindow(new byte[0]);
    CommittedBundle<byte[]> inputBundle =
        bundleFactory.<byte[]>createBundle(impulseOutput).add(impulse).commit(Instant.now());
    TransformEvaluator<byte[]> evaluator = factory.forApplication(stage, inputBundle);
    evaluator.processElement(impulse);
    TransformResult<byte[]> result = evaluator.finishBundle();
    assertThat(Iterables.size(result.getOutputBundles()), equalTo(1));
    CommittedBundle<?> outputs = getOnlyElement(result.getOutputBundles()).commit(Instant.now());
    assertThat(Iterables.size(outputs), equalTo(3));
  }

  @Test
  public void executesStageWithFlatten() throws Exception {
    ParDo.SingleOutput<byte[], KV<Integer, String>> parDo =
        ParDo.of(
            new DoFn<byte[], KV<Integer, String>>() {
              @ProcessElement
              public void process(ProcessContext ctxt) {
                ctxt.output(KV.of(1, "foo"));
                ctxt.output(KV.of(1, "bar"));
                ctxt.output(KV.of(2, "foo"));
              }
            });
    Pipeline p = Pipeline.create();

    PCollection<KV<Integer, String>> left = p.apply("left", Impulse.create()).apply(parDo);
    PCollection<KV<Integer, String>> right = p.apply("right", Impulse.create()).apply(parDo);
    PCollectionList.of(left).and(right).apply(Flatten.pCollections()).apply(GroupByKey.create());

    RunnerApi.Pipeline fusedPipeline =
        GreedyPipelineFuser.fuse(PipelineTranslation.toProto(p)).toPipeline();
    QueryablePipeline fusedQP = QueryablePipeline.forPipeline(fusedPipeline);
    PTransformNode leftRoot = null;
    PTransformNode rightRoot = null;
    for (PTransformNode root : fusedQP.getRootTransforms()) {
      if ("left".equals(root.getId())) {
        leftRoot = root;
      } else {
        rightRoot = root;
      }
    }
    checkState(leftRoot != null);
    checkState(rightRoot != null);
    PTransformNode stage =
        fusedPipeline.getRootTransformIdsList().stream()
            .map(
                id ->
                    PipelineNode.pTransform(
                        id, fusedPipeline.getComponents().getTransformsOrThrow(id)))
            .filter(node -> node.getTransform().getSpec().getUrn().equals(ExecutableStage.URN))
            .findFirst()
            .orElseThrow(IllegalArgumentException::new);

    WindowedValue<byte[]> impulse = WindowedValue.valueInGlobalWindow(new byte[0]);
    String inputId = getOnlyElement(stage.getTransform().getInputsMap().values());
    CommittedBundle<byte[]> inputBundle =
        bundleFactory
            .<byte[]>createBundle(
                PipelineNode.pCollection(
                    inputId, fusedPipeline.getComponents().getPcollectionsOrThrow(inputId)))
            .add(impulse)
            .commit(Instant.now());
    TransformEvaluator<byte[]> evaluator = factory.forApplication(stage, inputBundle);
    evaluator.processElement(impulse);
    TransformResult<byte[]> result = evaluator.finishBundle();
    assertThat(Iterables.size(result.getOutputBundles()), equalTo(1));
    CommittedBundle<?> outputs = getOnlyElement(result.getOutputBundles()).commit(Instant.now());
    assertThat(Iterables.size(outputs), equalTo(3));
  }
}