/*
 * 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.test.javaApiOperators;

import java.util.List;

import org.apache.flink.api.common.functions.RichFilterFunction;
import org.apache.flink.api.java.tuple.Tuple3;
import org.apache.flink.test.javaApiOperators.util.CollectionDataSets;
import org.apache.flink.test.util.MultipleProgramsTestBase;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;

@RunWith(Parameterized.class)
public class UnionITCase extends MultipleProgramsTestBase {

	private static final String FULL_TUPLE_3_STRING = "1,1,Hi\n" +
			"2,2,Hello\n" +
			"3,2,Hello world\n" +
			"4,3,Hello world, how are you?\n" +
			"5,3,I am fine.\n" +
			"6,3,Luke Skywalker\n" +
			"7,4,Comment#1\n" +
			"8,4,Comment#2\n" +
			"9,4,Comment#3\n" +
			"10,4,Comment#4\n" +
			"11,5,Comment#5\n" +
			"12,5,Comment#6\n" +
			"13,5,Comment#7\n" +
			"14,5,Comment#8\n" +
			"15,5,Comment#9\n" +
			"16,6,Comment#10\n" +
			"17,6,Comment#11\n" +
			"18,6,Comment#12\n" +
			"19,6,Comment#13\n" +
			"20,6,Comment#14\n" +
			"21,6,Comment#15\n";

	public UnionITCase(TestExecutionMode mode){
		super(mode);
	}

	@Test
	public void testUnion2IdenticalDataSets() throws Exception {
		/*
		 * Union of 2 Same Data Sets
		 */
		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
		DataSet<Tuple3<Integer, Long, String>> unionDs = ds.union(CollectionDataSets.get3TupleDataSet(env));

		List<Tuple3<Integer, Long, String>> result = unionDs.collect();

		String expected = FULL_TUPLE_3_STRING + FULL_TUPLE_3_STRING;

		compareResultAsTuples(result, expected);
	}

	@Test
	public void testUnion5IdenticalDataSets() throws Exception {
		/*
		 * Union of 5 same Data Sets, with multiple unions
		 */

		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
		DataSet<Tuple3<Integer, Long, String>> unionDs = ds.union(CollectionDataSets.get3TupleDataSet(env))
				.union(CollectionDataSets.get3TupleDataSet(env))
				.union(CollectionDataSets.get3TupleDataSet(env))
				.union(CollectionDataSets.get3TupleDataSet(env));

		List<Tuple3<Integer, Long, String>> result = unionDs.collect();

		String expected = FULL_TUPLE_3_STRING + FULL_TUPLE_3_STRING
				+ FULL_TUPLE_3_STRING +
				FULL_TUPLE_3_STRING +	FULL_TUPLE_3_STRING;

		compareResultAsTuples(result, expected);
	}

	@Test
	public void testUnionWithEmptyDataSet() throws Exception {
		/*
		 * Test on union with empty dataset
		 */
		final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

		// Don't know how to make an empty result in an other way than filtering it
		DataSet<Tuple3<Integer, Long, String>> empty = CollectionDataSets.get3TupleDataSet(env).
				filter(new RichFilter1());

		DataSet<Tuple3<Integer, Long, String>> unionDs = CollectionDataSets.get3TupleDataSet(env)
				.union(empty);

		List<Tuple3<Integer, Long, String>> result = unionDs.collect();

		String expected = FULL_TUPLE_3_STRING;

		compareResultAsTuples(result, expected);
	}

	public static class RichFilter1 extends RichFilterFunction<Tuple3<Integer,Long,String>> {
		private static final long serialVersionUID = 1L;

		@Override
		public boolean filter(Tuple3<Integer, Long, String> value) throws Exception {
			return false;
		}
	}

}