/*
 * 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.fn.harness;

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

import com.google.common.util.concurrent.Uninterruptibles;
import io.grpc.Server;
import io.grpc.ServerBuilder;
import io.grpc.stub.StreamObserver;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.function.Consumer;
import org.apache.beam.fn.harness.test.TestStreams;
import org.apache.beam.fn.v1.BeamFnApi;
import org.apache.beam.fn.v1.BeamFnApi.InstructionRequest;
import org.apache.beam.fn.v1.BeamFnApi.InstructionResponse;
import org.apache.beam.fn.v1.BeamFnApi.LogControl;
import org.apache.beam.fn.v1.BeamFnControlGrpc;
import org.apache.beam.fn.v1.BeamFnLoggingGrpc;
import org.apache.beam.sdk.extensions.gcp.options.GcsOptions;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link FnHarness}. */
@RunWith(JUnit4.class)
public class FnHarnessTest {
  private static final BeamFnApi.InstructionRequest INSTRUCTION_REQUEST =
      BeamFnApi.InstructionRequest.newBuilder()
      .setInstructionId("999L")
      .setRegister(BeamFnApi.RegisterRequest.getDefaultInstance())
      .build();
  private static final BeamFnApi.InstructionResponse INSTRUCTION_RESPONSE =
      BeamFnApi.InstructionResponse.newBuilder()
      .setInstructionId("999L")
      .setRegister(BeamFnApi.RegisterResponse.getDefaultInstance())
      .build();

  @Test
  public void testLaunchFnHarnessAndTeardownCleanly() throws Exception {
    PipelineOptions options = PipelineOptionsFactory.create();

    List<BeamFnApi.LogEntry> logEntries = new ArrayList<>();
    List<BeamFnApi.InstructionResponse> instructionResponses = new ArrayList<>();

    BeamFnLoggingGrpc.BeamFnLoggingImplBase loggingService =
        new BeamFnLoggingGrpc.BeamFnLoggingImplBase() {
      @Override
      public StreamObserver<BeamFnApi.LogEntry.List> logging(
          StreamObserver<LogControl> responseObserver) {
        return TestStreams.withOnNext(
            (BeamFnApi.LogEntry.List entries) -> logEntries.addAll(entries.getLogEntriesList()))
            .withOnCompleted(() -> responseObserver.onCompleted())
            .build();
      }
    };

    BeamFnControlGrpc.BeamFnControlImplBase controlService =
        new BeamFnControlGrpc.BeamFnControlImplBase() {
      @Override
      public StreamObserver<InstructionResponse> control(
          StreamObserver<InstructionRequest> responseObserver) {
        CountDownLatch waitForResponses = new CountDownLatch(1 /* number of responses expected */);
        options.as(GcsOptions.class).getExecutorService().submit(new Runnable() {
          @Override
          public void run() {
            responseObserver.onNext(INSTRUCTION_REQUEST);
            Uninterruptibles.awaitUninterruptibly(waitForResponses);
            responseObserver.onCompleted();
          }
        });
        return TestStreams.withOnNext(new Consumer<BeamFnApi.InstructionResponse>() {
          @Override
          public void accept(InstructionResponse t) {
            instructionResponses.add(t);
            waitForResponses.countDown();
          }
        }).withOnCompleted(waitForResponses::countDown).build();
      }
    };

    Server loggingServer = ServerBuilder.forPort(0).addService(loggingService).build();
    loggingServer.start();
    try {
      Server controlServer = ServerBuilder.forPort(0).addService(controlService).build();
      controlServer.start();
      try {
        BeamFnApi.ApiServiceDescriptor loggingDescriptor = BeamFnApi.ApiServiceDescriptor
            .newBuilder()
            .setId("1L")
            .setUrl("localhost:" + loggingServer.getPort())
            .build();
        BeamFnApi.ApiServiceDescriptor controlDescriptor = BeamFnApi.ApiServiceDescriptor
            .newBuilder()
            .setId("2L")
            .setUrl("localhost:" + controlServer.getPort())
            .build();

        FnHarness.main(options, loggingDescriptor, controlDescriptor);
        assertThat(instructionResponses, contains(INSTRUCTION_RESPONSE));
      } finally {
        controlServer.shutdownNow();
      }
    } finally {
      loggingServer.shutdownNow();
    }
  }
}