/***********************************************************************************************************************
 * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
 *
 * Licensed 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 eu.stratosphere.test.compiler.iterations;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

import org.junit.Test;

import eu.stratosphere.api.common.Plan;
import eu.stratosphere.api.java.DataSet;
import eu.stratosphere.api.java.DeltaIteration;
import eu.stratosphere.api.java.ExecutionEnvironment;
import eu.stratosphere.api.java.aggregation.Aggregations;
import eu.stratosphere.api.java.functions.FlatMapFunction;
import eu.stratosphere.api.java.functions.JoinFunction;
import eu.stratosphere.api.java.functions.MapFunction;
import eu.stratosphere.api.java.tuple.Tuple2;
import eu.stratosphere.api.java.tuple.Tuple3;
import eu.stratosphere.compiler.plan.DualInputPlanNode;
import eu.stratosphere.compiler.plan.OptimizedPlan;
import eu.stratosphere.compiler.plan.SolutionSetPlanNode;
import eu.stratosphere.compiler.plantranslate.NepheleJobGraphGenerator;
import eu.stratosphere.pact.runtime.shipping.ShipStrategyType;
import eu.stratosphere.pact.runtime.task.DriverStrategy;
import eu.stratosphere.test.compiler.util.CompilerTestBase;
import eu.stratosphere.util.Collector;

@SuppressWarnings("serial")
public class MultipleJoinsWithSolutionSetCompilerTest extends CompilerTestBase {
		
	private static final String JOIN_1 = "join1";
	private static final String JOIN_2 = "join2";
		
	@Test
	public void testMultiSolutionSetJoinPlan() {
		try {
			
			ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
			
			@SuppressWarnings("unchecked")
			DataSet<Tuple2<Long, Double>> inputData = env.fromElements(new Tuple2<Long, Double>(1L, 1.0));
			DataSet<Tuple2<Long, Double>> result = constructPlan(inputData, 10);
			
			// add two sinks, to test the case of branching after an iteration
			result.print();
			result.print();
		
			Plan p = env.createProgramPlan();
			
			OptimizedPlan optPlan = compileNoStats(p);
			
			OptimizerPlanNodeResolver or = getOptimizerPlanNodeResolver(optPlan);
			
			DualInputPlanNode join1 = or.getNode(JOIN_1);
			DualInputPlanNode join2 = or.getNode(JOIN_2);
			
			assertEquals(DriverStrategy.HYBRIDHASH_BUILD_FIRST, join1.getDriverStrategy());
			assertEquals(DriverStrategy.HYBRIDHASH_BUILD_SECOND, join2.getDriverStrategy());
			
			assertEquals(ShipStrategyType.PARTITION_HASH, join1.getInput2().getShipStrategy());
			assertEquals(ShipStrategyType.PARTITION_HASH, join2.getInput1().getShipStrategy());
			
			assertEquals(SolutionSetPlanNode.class, join1.getInput1().getSource().getClass());
			assertEquals(SolutionSetPlanNode.class, join2.getInput2().getSource().getClass());
			
			new NepheleJobGraphGenerator().compileJobGraph(optPlan);
		}
		catch (Exception e) {
			System.err.println(e.getMessage());
			e.printStackTrace();
			fail("Test erroneous: " + e.getMessage());
		}
	}
	
	
	
	public static DataSet<Tuple2<Long, Double>> constructPlan(DataSet<Tuple2<Long, Double>> initialData, int numIterations) {

		DeltaIteration<Tuple2<Long, Double>, Tuple2<Long, Double>> iteration = initialData.iterateDelta(initialData, numIterations, 0);
		
		DataSet<Tuple2<Long, Double>> delta = iteration.getSolutionSet()
				.join(iteration.getWorkset().flatMap(new Duplicator())).where(0).equalTo(0).with(new SummingJoin()).name(JOIN_1)
				.groupBy(0).aggregate(Aggregations.MIN, 1).map(new Expander())
				.join(iteration.getSolutionSet()).where(0).equalTo(0).with(new SummingJoinProject()).name(JOIN_2);
		
		DataSet<Tuple2<Long, Double>> changes = delta.groupBy(0).aggregate(Aggregations.SUM, 1);
		
		DataSet<Tuple2<Long, Double>> result = iteration.closeWith(delta, changes);
		
		return result;
	}
	
	public static final class SummingJoin extends JoinFunction<Tuple2<Long, Double>, Tuple2<Long, Double>, Tuple2<Long, Double>> {

		@Override
		public Tuple2<Long, Double> join(Tuple2<Long, Double> first, Tuple2<Long, Double> second) {
			return new Tuple2<Long, Double>(first.f0, first.f1 + second.f1);
		}
	}
	
	public static final class SummingJoinProject extends JoinFunction<Tuple3<Long, Double, Double>, Tuple2<Long, Double>, Tuple2<Long, Double>> {

		@Override
		public Tuple2<Long, Double> join(Tuple3<Long, Double, Double> first, Tuple2<Long, Double> second) {
			return new Tuple2<Long, Double>(first.f0, first.f1 + first.f2 + second.f1);
		}
	}
	
	public static final class Duplicator extends FlatMapFunction<Tuple2<Long, Double>, Tuple2<Long, Double>> {

		@Override
		public void flatMap(Tuple2<Long, Double> value, Collector<Tuple2<Long, Double>> out) {
			out.collect(value);
			out.collect(value);
		}
	}
	
	public static final class Expander extends MapFunction<Tuple2<Long, Double>, Tuple3<Long, Double, Double>> {

		@Override
		public Tuple3<Long, Double, Double> map(Tuple2<Long, Double> value) {
			return new Tuple3<Long, Double, Double>(value.f0, value.f1, value.f1 * 2);
		}
	}
}