/*
 * 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.flink.runtime.operators.chaining;

import java.util.ArrayList;
import java.util.List;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.common.functions.GroupCombineFunction;
import org.apache.flink.api.common.functions.GroupReduceFunction;
import org.apache.flink.api.common.operators.util.UserCodeClassWrapper;
import org.apache.flink.runtime.testutils.recordutils.RecordComparatorFactory;
import org.apache.flink.runtime.testutils.recordutils.RecordSerializerFactory;
import org.apache.flink.api.common.functions.RichGroupReduceFunction;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.runtime.io.network.api.writer.ResultPartitionWriter;
import org.apache.flink.runtime.operators.DriverStrategy;
import org.apache.flink.runtime.operators.BatchTask;
import org.apache.flink.runtime.operators.FlatMapDriver;
import org.apache.flink.runtime.operators.FlatMapTaskTest.MockMapStub;
import org.apache.flink.runtime.operators.ReduceTaskTest.MockCombiningReduceStub;
import org.apache.flink.runtime.operators.shipping.ShipStrategyType;
import org.apache.flink.runtime.operators.testutils.TaskTestBase;
import org.apache.flink.runtime.operators.testutils.UniformRecordGenerator;
import org.apache.flink.runtime.operators.util.TaskConfig;
import org.apache.flink.runtime.taskmanager.Task;
import org.apache.flink.types.IntValue;
import org.apache.flink.types.Record;
import org.apache.flink.util.Collector;
import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PowerMockIgnore;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

@RunWith(PowerMockRunner.class)
@PrepareForTest({Task.class, ResultPartitionWriter.class})
@PowerMockIgnore({"javax.management.*", "com.sun.jndi.*"})
public class ChainTaskTest extends TaskTestBase {
	
	private static final int MEMORY_MANAGER_SIZE = 1024 * 1024 * 3;

	private static final int NETWORK_BUFFER_SIZE = 1024;
	
	private final List<Record> outList = new ArrayList<>();
	
	@SuppressWarnings("unchecked")
	private final RecordComparatorFactory compFact = new RecordComparatorFactory(new int[]{0}, new Class[]{IntValue.class}, new boolean[] {true});
	private final RecordSerializerFactory serFact = RecordSerializerFactory.get();
	
	@Test
	public void testMapTask() {
		final int keyCnt = 100;
		final int valCnt = 20;

		final double memoryFraction = 1.0;
		
		try {
		
			// environment
			initEnvironment(MEMORY_MANAGER_SIZE, NETWORK_BUFFER_SIZE);
			addInput(new UniformRecordGenerator(keyCnt, valCnt, false), 0);
			addOutput(this.outList);
			
			// chained combine config
			{
				final TaskConfig combineConfig = new TaskConfig(new Configuration());
	
				// input
				combineConfig.addInputToGroup(0);
				combineConfig.setInputSerializer(serFact, 0);
				
				// output
				combineConfig.addOutputShipStrategy(ShipStrategyType.FORWARD);
				combineConfig.setOutputSerializer(serFact);
				
				// driver
				combineConfig.setDriverStrategy(DriverStrategy.SORTED_GROUP_COMBINE);
				combineConfig.setDriverComparator(compFact, 0);
				combineConfig.setDriverComparator(compFact, 1);
				combineConfig.setRelativeMemoryDriver(memoryFraction);
				
				// udf
				combineConfig.setStubWrapper(new UserCodeClassWrapper<>(MockCombiningReduceStub.class));
				
				getTaskConfig().addChainedTask(SynchronousChainedCombineDriver.class, combineConfig, "combine");
			}
			
			// chained map+combine
			{
				BatchTask<FlatMapFunction<Record, Record>, Record> testTask =
											new BatchTask<>();
				registerTask(testTask, FlatMapDriver.class, MockMapStub.class);
				
				try {
					testTask.invoke();
				} catch (Exception e) {
					e.printStackTrace();
					Assert.fail("Invoke method caused exception.");
				}
			}
			
			Assert.assertEquals(keyCnt, this.outList.size());
		}
		catch (Exception e) {
			e.printStackTrace();
			Assert.fail(e.getMessage());
		}
	}
	
	@Test
	public void testFailingMapTask() {
		int keyCnt = 100;
		int valCnt = 20;

		final long memorySize = 1024 * 1024 * 3;
		final int bufferSize = 1014*1024;
		final double memoryFraction = 1.0;
		
		try {
			// environment
			initEnvironment(memorySize, bufferSize);
			addInput(new UniformRecordGenerator(keyCnt, valCnt, false), 0);
			addOutput(this.outList);
	
			// chained combine config
			{
				final TaskConfig combineConfig = new TaskConfig(new Configuration());
	
				// input
				combineConfig.addInputToGroup(0);
				combineConfig.setInputSerializer(serFact, 0);
				
				// output
				combineConfig.addOutputShipStrategy(ShipStrategyType.FORWARD);
				combineConfig.setOutputSerializer(serFact);
				
				// driver
				combineConfig.setDriverStrategy(DriverStrategy.SORTED_GROUP_COMBINE);
				combineConfig.setDriverComparator(compFact, 0);
				combineConfig.setDriverComparator(compFact, 1);
				combineConfig.setRelativeMemoryDriver(memoryFraction);
				
				// udf
				combineConfig.setStubWrapper(new UserCodeClassWrapper<>(MockFailingCombineStub.class));
				
				getTaskConfig().addChainedTask(SynchronousChainedCombineDriver.class, combineConfig, "combine");
			}
			
			// chained map+combine
			{
				final BatchTask<FlatMapFunction<Record, Record>, Record> testTask =
											new BatchTask<>();
				
				super.registerTask(testTask, FlatMapDriver.class, MockMapStub.class);
	
				boolean stubFailed = false;
				
				try {
					testTask.invoke();
				} catch (Exception e) {
					stubFailed = true;
				}
				
				Assert.assertTrue("Function exception was not forwarded.", stubFailed);
			}
		}
		catch (Exception e) {
			e.printStackTrace();
			Assert.fail(e.getMessage());
		}
	}
	
	public static final class MockFailingCombineStub implements
		GroupReduceFunction<Record, Record>,
		GroupCombineFunction<Record, Record> {
		private static final long serialVersionUID = 1L;
		
		private int cnt = 0;

		@Override
		public void reduce(Iterable<Record> records, Collector<Record> out) throws Exception {
			if (++this.cnt >= 5) {
				throw new RuntimeException("Expected Test Exception");
			}
			
			for (Record r : records) {
				out.collect(r);
			}
		}

		@Override
		public void combine(Iterable<Record> values, Collector<Record> out) throws Exception {
			reduce(values, out);
		}
	}
}