/*
 * 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.api.common.operators.base;

import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.api.common.TaskInfo;
import org.apache.flink.api.common.functions.GroupReduceFunction;
import org.apache.flink.api.common.functions.RichGroupReduceFunction;
import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.api.common.functions.util.RuntimeUDFContext;
import org.apache.flink.api.common.operators.UnaryOperatorInformation;
import org.apache.flink.api.common.operators.base.utils.TestAccumulatorRegistry;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.typeutils.TypeInfoParser;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.core.fs.Path;
import org.apache.flink.metrics.groups.UnregisteredMetricsGroup;
import org.apache.flink.util.Collector;

import org.junit.Test;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicBoolean;

import static java.util.Arrays.asList;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

/**
 * Tests for {@link GroupReduceFunction}.
 */
@SuppressWarnings({"serial", "unchecked"})
public class GroupReduceOperatorTest implements java.io.Serializable {

	@Test
	public void testGroupReduceCollection() {
		try {
			final GroupReduceFunction<Tuple2<String, Integer>, Tuple2<String,
					Integer>> reducer = new GroupReduceFunction<Tuple2<String, Integer>,
					Tuple2<String, Integer>>() {

				@Override
				public void reduce(Iterable<Tuple2<String, Integer>> values,
									Collector<Tuple2<String, Integer>> out) throws Exception {
					Iterator<Tuple2<String, Integer>> input = values.iterator();

					Tuple2<String, Integer> result = input.next();
					int sum = result.f1;
					while (input.hasNext()) {
						Tuple2<String, Integer> next = input.next();
						sum += next.f1;
					}
					result.f1 = sum;
					out.collect(result);
				}
			};

			GroupReduceOperatorBase<Tuple2<String, Integer>, Tuple2<String, Integer>,
					GroupReduceFunction<Tuple2<String, Integer>, Tuple2<String,
							Integer>>> op = new GroupReduceOperatorBase<Tuple2<String, Integer>,
					Tuple2<String, Integer>, GroupReduceFunction<Tuple2<String, Integer>,
					Tuple2<String, Integer>>>(reducer, new UnaryOperatorInformation<Tuple2<String,
					Integer>, Tuple2<String, Integer>>(TypeInfoParser.<Tuple2<String,
					Integer>>parse("Tuple2<String, Integer>"), TypeInfoParser.<Tuple2<String,
					Integer>>parse("Tuple2<String, Integer>")), new int[]{0}, "TestReducer");

			List<Tuple2<String, Integer>> input = new ArrayList<Tuple2<String,
					Integer>>(asList(new Tuple2<String, Integer>("foo", 1), new Tuple2<String,
					Integer>("foo", 3), new Tuple2<String, Integer>("bar", 2), new Tuple2<String,
					Integer>("bar", 4)));

			ExecutionConfig executionConfig = new ExecutionConfig();
			executionConfig.disableObjectReuse();
			List<Tuple2<String, Integer>> resultMutableSafe = op.executeOnCollections(input, null, executionConfig);
			executionConfig.enableObjectReuse();
			List<Tuple2<String, Integer>> resultRegular = op.executeOnCollections(input, null, executionConfig);

			Set<Tuple2<String, Integer>> resultSetMutableSafe = new HashSet<Tuple2<String, Integer>>(resultMutableSafe);
			Set<Tuple2<String, Integer>> resultSetRegular = new HashSet<Tuple2<String, Integer>>(resultRegular);

			Set<Tuple2<String, Integer>> expectedResult = new HashSet<Tuple2<String,
					Integer>>(asList(new Tuple2<String, Integer>("foo", 4), new Tuple2<String,
					Integer>("bar", 6)));

			assertEquals(expectedResult, resultSetMutableSafe);
			assertEquals(expectedResult, resultSetRegular);
		}
		catch (Exception e) {
			e.printStackTrace();
			fail(e.getMessage());
		}
	}

	@Test
	public void testGroupReduceCollectionWithRuntimeContext() {
		try {
			final String taskName = "Test Task";
			final AtomicBoolean opened = new AtomicBoolean();
			final AtomicBoolean closed = new AtomicBoolean();

			final RichGroupReduceFunction<Tuple2<String, Integer>, Tuple2<String,
					Integer>> reducer = new RichGroupReduceFunction<Tuple2<String, Integer>,
					Tuple2<String, Integer>>() {

				@Override
				public void reduce(Iterable<Tuple2<String, Integer>> values,
									Collector<Tuple2<String, Integer>> out) throws Exception {
					Iterator<Tuple2<String, Integer>> input = values.iterator();

					Tuple2<String, Integer> result = input.next();
					int sum = result.f1;
					while (input.hasNext()) {
						Tuple2<String, Integer> next = input.next();
						sum += next.f1;
					}
					result.f1 = sum;
					out.collect(result);
				}

				@Override
				public void open(Configuration parameters) throws Exception {
					opened.set(true);
					RuntimeContext ctx = getRuntimeContext();
					assertEquals(0, ctx.getIndexOfThisSubtask());
					assertEquals(1, ctx.getNumberOfParallelSubtasks());
					assertEquals(taskName, ctx.getTaskName());
				}

				@Override
				public void close() throws Exception {
					closed.set(true);
				}
			};

			GroupReduceOperatorBase<Tuple2<String, Integer>, Tuple2<String, Integer>,
					GroupReduceFunction<Tuple2<String, Integer>, Tuple2<String,
							Integer>>> op = new GroupReduceOperatorBase<Tuple2<String, Integer>,
					Tuple2<String, Integer>, GroupReduceFunction<Tuple2<String, Integer>,
					Tuple2<String, Integer>>>(reducer, new UnaryOperatorInformation<Tuple2<String,
					Integer>, Tuple2<String, Integer>>(TypeInfoParser.<Tuple2<String,
					Integer>>parse("Tuple2<String, Integer>"), TypeInfoParser.<Tuple2<String,
					Integer>>parse("Tuple2<String, Integer>")), new int[]{0}, "TestReducer");

			List<Tuple2<String, Integer>> input = new ArrayList<Tuple2<String,
					Integer>>(asList(new Tuple2<String, Integer>("foo", 1), new Tuple2<String,
					Integer>("foo", 3), new Tuple2<String, Integer>("bar", 2), new Tuple2<String,
					Integer>("bar", 4)));

			final TaskInfo taskInfo = new TaskInfo(taskName, 1, 0, 1, 0);

			ExecutionConfig executionConfig = new ExecutionConfig();
			executionConfig.disableObjectReuse();
			List<Tuple2<String, Integer>> resultMutableSafe = op.executeOnCollections(input,
					new RuntimeUDFContext(taskInfo, null, executionConfig,
							new HashMap<String, Future<Path>>(),
							new TestAccumulatorRegistry(),
							new UnregisteredMetricsGroup()),
					executionConfig);

			executionConfig.enableObjectReuse();
			List<Tuple2<String, Integer>> resultRegular = op.executeOnCollections(input,
					new RuntimeUDFContext(taskInfo, null, executionConfig,
							new HashMap<String, Future<Path>>(),
							new TestAccumulatorRegistry(),
							new UnregisteredMetricsGroup()),
					executionConfig);

			Set<Tuple2<String, Integer>> resultSetMutableSafe = new HashSet<Tuple2<String, Integer>>(resultMutableSafe);
			Set<Tuple2<String, Integer>> resultSetRegular = new HashSet<Tuple2<String, Integer>>(resultRegular);

			Set<Tuple2<String, Integer>> expectedResult = new HashSet<Tuple2<String,
					Integer>>(asList(new Tuple2<String, Integer>("foo", 4), new Tuple2<String,
					Integer>("bar", 6)));

			assertEquals(expectedResult, resultSetMutableSafe);
			assertEquals(expectedResult, resultSetRegular);

			assertTrue(opened.get());
			assertTrue(closed.get());
		} catch (Exception e) {
			e.printStackTrace();
			fail(e.getMessage());
		}
	}
}