/*
 * 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;

import static org.hamcrest.Matchers.containsInAnyOrder;
import static org.hamcrest.Matchers.nullValue;
import static org.junit.Assert.assertThat;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import com.google.common.collect.ImmutableList;
import org.apache.beam.sdk.coders.KvCoder;
import org.apache.beam.sdk.coders.StringUtf8Coder;
import org.apache.beam.sdk.coders.VoidCoder;
import org.apache.beam.sdk.runners.AppliedPTransform;
import org.apache.beam.sdk.testing.TestPipeline;
import org.apache.beam.sdk.transforms.Create;
import org.apache.beam.sdk.transforms.GroupByKey;
import org.apache.beam.sdk.transforms.Values;
import org.apache.beam.sdk.transforms.View;
import org.apache.beam.sdk.transforms.WithKeys;
import org.apache.beam.sdk.util.WindowedValue;
import org.apache.beam.sdk.values.PCollection;
import org.apache.beam.sdk.values.PCollectionView;
import org.joda.time.Instant;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link ViewEvaluatorFactory}. */
@RunWith(JUnit4.class)
public class ViewEvaluatorFactoryTest {
  private BundleFactory bundleFactory = ImmutableListBundleFactory.create();

  @Rule public TestPipeline p = TestPipeline.create().enableAbandonedNodeEnforcement(false);

  @Test
  public void testInMemoryEvaluator() throws Exception {
    PCollection<String> input = p.apply(Create.of("foo", "bar"));
    PCollectionView<Iterable<String>> pCollectionView = input.apply(View.asIterable());
    PCollection<Iterable<String>> concat =
        input
            .apply(WithKeys.of((Void) null))
            .setCoder(KvCoder.of(VoidCoder.of(), StringUtf8Coder.of()))
            .apply(GroupByKey.create())
            .apply(Values.create());
    PCollection<Iterable<String>> view =
        concat.apply(new ViewOverrideFactory.WriteView<>(pCollectionView));

    EvaluationContext context = mock(EvaluationContext.class);
    TestViewWriter<String, Iterable<String>> viewWriter = new TestViewWriter<>();
    when(context.createPCollectionViewWriter(concat, pCollectionView)).thenReturn(viewWriter);

    CommittedBundle<String> inputBundle = bundleFactory.createBundle(input).commit(Instant.now());
    AppliedPTransform<?, ?, ?> producer = DirectGraphs.getProducer(view);
    TransformEvaluator<Iterable<String>> evaluator =
        new ViewEvaluatorFactory(context).forApplication(producer, inputBundle);

    evaluator.processElement(WindowedValue.valueInGlobalWindow(ImmutableList.of("foo", "bar")));
    assertThat(viewWriter.latest, nullValue());

    evaluator.finishBundle();
    assertThat(
        viewWriter.latest,
        containsInAnyOrder(
            WindowedValue.valueInGlobalWindow("foo"), WindowedValue.valueInGlobalWindow("bar")));
  }

  private static class TestViewWriter<ElemT, ViewT> implements PCollectionViewWriter<ElemT, ViewT> {
    private Iterable<WindowedValue<ElemT>> latest;

    @Override
    public void add(Iterable<WindowedValue<ElemT>> values) {
      latest = values;
    }
  }
}
