/*
 * 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.optimizer;

import org.apache.flink.api.common.Plan;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.io.DiscardingOutputFormat;
import org.apache.flink.api.java.operators.DeltaIteration;
import org.apache.flink.api.java.operators.IterativeDataSet;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.optimizer.plan.OptimizedPlan;
import org.apache.flink.optimizer.plantranslate.JobGraphGenerator;
import org.apache.flink.optimizer.testfunctions.DummyFlatJoinFunction;
import org.apache.flink.optimizer.testfunctions.IdentityKeyExtractor;
import org.apache.flink.optimizer.testfunctions.IdentityMapper;
import org.apache.flink.optimizer.util.CompilerTestBase;

import org.junit.Test;

import static org.junit.Assert.*;

@SuppressWarnings({"serial", "unchecked"})
public class NestedIterationsTest extends CompilerTestBase {

    @Test
    public void testRejectNestedBulkIterations() {
        try {
            ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

            DataSet<Long> data = env.generateSequence(1, 100);

            IterativeDataSet<Long> outerIteration = data.iterate(100);

            IterativeDataSet<Long> innerIteration =
                    outerIteration.map(new IdentityMapper<Long>()).iterate(100);

            DataSet<Long> innerResult =
                    innerIteration.closeWith(innerIteration.map(new IdentityMapper<Long>()));

            DataSet<Long> outerResult =
                    outerIteration.closeWith(innerResult.map(new IdentityMapper<Long>()));

            outerResult.output(new DiscardingOutputFormat<Long>());

            Plan p = env.createProgramPlan();

            try {
                compileNoStats(p);
            } catch (CompilerException e) {
                assertTrue(e.getMessage().toLowerCase().indexOf("nested iterations") != -1);
            }
        } catch (Exception e) {
            e.printStackTrace();
            fail(e.getMessage());
        }
    }

    @Test
    public void testRejectNestedWorksetIterations() {
        try {
            ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

            DataSet<Tuple2<Long, Long>> data = env.fromElements(new Tuple2<Long, Long>(0L, 0L));

            DeltaIteration<Tuple2<Long, Long>, Tuple2<Long, Long>> outerIteration =
                    data.iterateDelta(data, 100, 0);

            DataSet<Tuple2<Long, Long>> inOuter =
                    outerIteration.getWorkset().map(new IdentityMapper<Tuple2<Long, Long>>());

            DeltaIteration<Tuple2<Long, Long>, Tuple2<Long, Long>> innerIteration =
                    inOuter.iterateDelta(inOuter, 100, 0);

            DataSet<Tuple2<Long, Long>> inInner =
                    innerIteration.getWorkset().map(new IdentityMapper<Tuple2<Long, Long>>());

            DataSet<Tuple2<Long, Long>> innerResult =
                    innerIteration
                            .closeWith(inInner, inInner)
                            .map(new IdentityMapper<Tuple2<Long, Long>>());

            DataSet<Tuple2<Long, Long>> outerResult =
                    outerIteration.closeWith(innerResult, innerResult);

            outerResult.output(new DiscardingOutputFormat<Tuple2<Long, Long>>());

            Plan p = env.createProgramPlan();

            try {
                compileNoStats(p);
            } catch (CompilerException e) {
                assertTrue(e.getMessage().toLowerCase().indexOf("nested iterations") != -1);
            }
        } catch (Exception e) {
            e.printStackTrace();
            fail(e.getMessage());
        }
    }

    @Test
    public void testBulkIterationInClosure() {
        try {
            ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

            DataSet<Long> data1 = env.generateSequence(1, 100);
            DataSet<Long> data2 = env.generateSequence(1, 100);

            IterativeDataSet<Long> firstIteration = data1.iterate(100);

            DataSet<Long> firstResult =
                    firstIteration.closeWith(firstIteration.map(new IdentityMapper<Long>()));

            IterativeDataSet<Long> mainIteration =
                    data2.map(new IdentityMapper<Long>()).iterate(100);

            DataSet<Long> joined =
                    mainIteration
                            .join(firstResult)
                            .where(new IdentityKeyExtractor<Long>())
                            .equalTo(new IdentityKeyExtractor<Long>())
                            .with(new DummyFlatJoinFunction<Long>());

            DataSet<Long> mainResult = mainIteration.closeWith(joined);

            mainResult.output(new DiscardingOutputFormat<Long>());

            Plan p = env.createProgramPlan();

            // optimizer should be able to translate this
            OptimizedPlan op = compileNoStats(p);

            // job graph generator should be able to translate this
            new JobGraphGenerator().compileJobGraph(op);
        } catch (Exception e) {
            e.printStackTrace();
            fail(e.getMessage());
        }
    }

    @Test
    public void testDeltaIterationInClosure() {
        try {
            ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();

            DataSet<Tuple2<Long, Long>> data1 = env.fromElements(new Tuple2<Long, Long>(0L, 0L));
            DataSet<Tuple2<Long, Long>> data2 = env.fromElements(new Tuple2<Long, Long>(0L, 0L));

            DeltaIteration<Tuple2<Long, Long>, Tuple2<Long, Long>> firstIteration =
                    data1.iterateDelta(data1, 100, 0);

            DataSet<Tuple2<Long, Long>> inFirst =
                    firstIteration.getWorkset().map(new IdentityMapper<Tuple2<Long, Long>>());

            DataSet<Tuple2<Long, Long>> firstResult =
                    firstIteration
                            .closeWith(inFirst, inFirst)
                            .map(new IdentityMapper<Tuple2<Long, Long>>());

            DeltaIteration<Tuple2<Long, Long>, Tuple2<Long, Long>> mainIteration =
                    data2.iterateDelta(data2, 100, 0);

            DataSet<Tuple2<Long, Long>> joined =
                    mainIteration
                            .getWorkset()
                            .join(firstResult)
                            .where(0)
                            .equalTo(0)
                            .projectFirst(0)
                            .projectSecond(0);

            DataSet<Tuple2<Long, Long>> mainResult = mainIteration.closeWith(joined, joined);

            mainResult.output(new DiscardingOutputFormat<Tuple2<Long, Long>>());

            Plan p = env.createProgramPlan();

            // optimizer should be able to translate this
            OptimizedPlan op = compileNoStats(p);

            // job graph generator should be able to translate this
            new JobGraphGenerator().compileJobGraph(op);
        } catch (Exception e) {
            e.printStackTrace();
            fail(e.getMessage());
        }
    }
}