/*
 * 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.operators;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.functions.MapPartitionFunction;
import org.apache.flink.api.common.operators.Order;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.api.java.tuple.Tuple1;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.tuple.Tuple3;
import org.apache.flink.api.java.tuple.Tuple5;
import org.apache.flink.test.operators.util.CollectionDataSets;
import org.apache.flink.test.operators.util.CollectionDataSets.POJO;
import org.apache.flink.test.util.MultipleProgramsTestBase;
import org.apache.flink.util.Collector;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

import java.io.Serializable;
import java.util.Iterator;
import java.util.List;

/** Tests for {@link DataSet#sortPartition}. */
@RunWith(Parameterized.class)
public class SortPartitionITCase extends MultipleProgramsTestBase {

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

    @Test
    public void testSortPartitionByKeyField() throws Exception {
        /*
         * Test sort partition on key field
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(4);

        DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper<Tuple3<Integer, Long, String>>())
                        .setParallelism(4) // parallelize input
                        .sortPartition(1, Order.DESCENDING)
                        .mapPartition(new OrderCheckMapper<>(new Tuple3Checker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @Test
    public void testSortPartitionByTwoKeyFields() throws Exception {
        /*
         * Test sort partition on two key fields
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(2);

        DataSet<Tuple5<Integer, Long, Integer, String, Long>> ds =
                CollectionDataSets.get5TupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper<Tuple5<Integer, Long, Integer, String, Long>>())
                        .setParallelism(2) // parallelize input
                        .sortPartition(4, Order.ASCENDING)
                        .sortPartition(2, Order.DESCENDING)
                        .mapPartition(new OrderCheckMapper<>(new Tuple5Checker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @SuppressWarnings({"rawtypes", "unchecked"})
    @Test
    public void testSortPartitionByFieldExpression() throws Exception {
        /*
         * Test sort partition on field expression
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(4);

        DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper())
                        .setParallelism(4) // parallelize input
                        .sortPartition("f1", Order.DESCENDING)
                        .mapPartition(new OrderCheckMapper<>(new Tuple3Checker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @Test
    public void testSortPartitionByTwoFieldExpressions() throws Exception {
        /*
         * Test sort partition on two field expressions
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(2);

        DataSet<Tuple5<Integer, Long, Integer, String, Long>> ds =
                CollectionDataSets.get5TupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper<Tuple5<Integer, Long, Integer, String, Long>>())
                        .setParallelism(2) // parallelize input
                        .sortPartition("f4", Order.ASCENDING)
                        .sortPartition("f2", Order.DESCENDING)
                        .mapPartition(new OrderCheckMapper<>(new Tuple5Checker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @Test
    public void testSortPartitionByNestedFieldExpression() throws Exception {
        /*
         * Test sort partition on nested field expressions
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(3);

        DataSet<Tuple2<Tuple2<Integer, Integer>, String>> ds =
                CollectionDataSets.getGroupSortedNestedTupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper<Tuple2<Tuple2<Integer, Integer>, String>>())
                        .setParallelism(3) // parallelize input
                        .sortPartition("f0.f1", Order.ASCENDING)
                        .sortPartition("f1", Order.DESCENDING)
                        .mapPartition(new OrderCheckMapper<>(new NestedTupleChecker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @Test
    public void testSortPartitionPojoByNestedFieldExpression() throws Exception {
        /*
         * Test sort partition on field expression
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(3);

        DataSet<POJO> ds = CollectionDataSets.getMixedPojoDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper<POJO>())
                        .setParallelism(1) // parallelize input
                        .sortPartition("nestedTupleWithCustom.f1.myString", Order.ASCENDING)
                        .sortPartition("number", Order.DESCENDING)
                        .mapPartition(new OrderCheckMapper<>(new PojoChecker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @Test
    public void testSortPartitionParallelismChange() throws Exception {
        /*
         * Test sort partition with parallelism change
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(3);

        DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.sortPartition(1, Order.DESCENDING)
                        .setParallelism(3) // change parallelism
                        .mapPartition(new OrderCheckMapper<>(new Tuple3Checker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @Test
    public void testSortPartitionWithKeySelector1() throws Exception {
        /*
         * Test sort partition on an extracted key
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(4);

        DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper<Tuple3<Integer, Long, String>>())
                        .setParallelism(4) // parallelize input
                        .sortPartition(
                                new KeySelector<Tuple3<Integer, Long, String>, Long>() {
                                    @Override
                                    public Long getKey(Tuple3<Integer, Long, String> value)
                                            throws Exception {
                                        return value.f1;
                                    }
                                },
                                Order.ASCENDING)
                        .mapPartition(new OrderCheckMapper<>(new Tuple3AscendingChecker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    @Test
    public void testSortPartitionWithKeySelector2() throws Exception {
        /*
         * Test sort partition on an extracted key
         */

        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(4);

        DataSet<Tuple3<Integer, Long, String>> ds = CollectionDataSets.get3TupleDataSet(env);
        List<Tuple1<Boolean>> result =
                ds.map(new IdMapper<Tuple3<Integer, Long, String>>())
                        .setParallelism(4) // parallelize input
                        .sortPartition(
                                new KeySelector<
                                        Tuple3<Integer, Long, String>, Tuple2<Integer, Long>>() {
                                    @Override
                                    public Tuple2<Integer, Long> getKey(
                                            Tuple3<Integer, Long, String> value) throws Exception {
                                        return new Tuple2<>(value.f0, value.f1);
                                    }
                                },
                                Order.DESCENDING)
                        .mapPartition(new OrderCheckMapper<>(new Tuple3Checker()))
                        .distinct()
                        .collect();

        String expected = "(true)\n";

        compareResultAsText(result, expected);
    }

    private interface OrderChecker<T> extends Serializable {
        boolean inOrder(T t1, T t2);
    }

    @SuppressWarnings("serial")
    private static class Tuple3Checker implements OrderChecker<Tuple3<Integer, Long, String>> {
        @Override
        public boolean inOrder(Tuple3<Integer, Long, String> t1, Tuple3<Integer, Long, String> t2) {
            return t1.f1 >= t2.f1;
        }
    }

    @SuppressWarnings("serial")
    private static class Tuple3AscendingChecker
            implements OrderChecker<Tuple3<Integer, Long, String>> {
        @Override
        public boolean inOrder(Tuple3<Integer, Long, String> t1, Tuple3<Integer, Long, String> t2) {
            return t1.f1 <= t2.f1;
        }
    }

    @SuppressWarnings("serial")
    private static class Tuple5Checker
            implements OrderChecker<Tuple5<Integer, Long, Integer, String, Long>> {
        @Override
        public boolean inOrder(
                Tuple5<Integer, Long, Integer, String, Long> t1,
                Tuple5<Integer, Long, Integer, String, Long> t2) {
            return t1.f4 < t2.f4 || t1.f4.equals(t2.f4) && t1.f2 >= t2.f2;
        }
    }

    @SuppressWarnings("serial")
    private static class NestedTupleChecker
            implements OrderChecker<Tuple2<Tuple2<Integer, Integer>, String>> {
        @Override
        public boolean inOrder(
                Tuple2<Tuple2<Integer, Integer>, String> t1,
                Tuple2<Tuple2<Integer, Integer>, String> t2) {
            return t1.f0.f1 < t2.f0.f1 || t1.f0.f1.equals(t2.f0.f1) && t1.f1.compareTo(t2.f1) >= 0;
        }
    }

    @SuppressWarnings("serial")
    private static class PojoChecker implements OrderChecker<POJO> {
        @Override
        public boolean inOrder(POJO t1, POJO t2) {
            return t1.nestedTupleWithCustom.f1.myString.compareTo(
                                    t2.nestedTupleWithCustom.f1.myString)
                            < 0
                    || t1.nestedTupleWithCustom.f1.myString.compareTo(
                                            t2.nestedTupleWithCustom.f1.myString)
                                    == 0
                            && t1.number >= t2.number;
        }
    }

    @SuppressWarnings("unused, serial")
    private static class OrderCheckMapper<T> implements MapPartitionFunction<T, Tuple1<Boolean>> {

        OrderChecker<T> checker;

        public OrderCheckMapper() {}

        public OrderCheckMapper(OrderChecker<T> checker) {
            this.checker = checker;
        }

        @Override
        public void mapPartition(Iterable<T> values, Collector<Tuple1<Boolean>> out)
                throws Exception {

            Iterator<T> it = values.iterator();
            if (!it.hasNext()) {
                out.collect(new Tuple1<>(true));
            } else {
                T last = it.next();

                while (it.hasNext()) {
                    T next = it.next();
                    if (!checker.inOrder(last, next)) {
                        out.collect(new Tuple1<>(false));
                        return;
                    }
                    last = next;
                }
                out.collect(new Tuple1<>(true));
            }
        }
    }

    @SuppressWarnings("serial")
    private static class IdMapper<T> implements MapFunction<T, T> {

        @Override
        public T map(T value) throws Exception {
            return value;
        }
    }
}