/*
 * Licensed to Crate.IO GmbH ("Crate") under one or more contributor
 * license agreements.  See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.  Crate 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.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial agreement.
 */

package io.crate.operation.merge;

import com.google.common.base.Function;
import com.google.common.collect.Iterables;
import com.google.common.collect.Ordering;
import io.crate.data.ArrayBucket;
import io.crate.data.Bucket;
import io.crate.data.Row;
import io.crate.operation.projectors.sorting.OrderingByPosition;
import io.crate.test.integration.CrateUnitTest;
import io.crate.testing.TestingHelpers;
import org.junit.Test;

import javax.annotation.Nullable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

import static org.hamcrest.core.Is.is;

public class SortedPagingIteratorTest extends CrateUnitTest {

    public static final Ordering<Row> ORDERING =
        OrderingByPosition.rowOrdering(new int[]{0}, new boolean[]{false}, new Boolean[]{null});

    @Test
    public void testTwoBucketsAndTwoPagesAreSortedCorrectly() throws Exception {
        SortedPagingIterator<Void, Row> pagingIterator = new SortedPagingIterator<>(ORDERING, randomBoolean());

        pagingIterator.merge(numberedBuckets(Arrays.<Bucket>asList(
            new ArrayBucket(new Object[][]{
                new Object[]{"a"},
                new Object[]{"b"},
                new Object[]{"c"}}),
            new ArrayBucket(new Object[][]{
                new Object[]{"x"},
                new Object[]{"y"},
            })
        )));

        List<Object[]> rows = new ArrayList<>();

        consumeRows(pagingIterator, rows);

        assertThat(rows.size(), is(3));
        assertThat(TestingHelpers.printRows(rows), is("a\nb\nc\n"));

        pagingIterator.merge(numberedBuckets(Arrays.<Bucket>asList(
            new ArrayBucket(new Object[][]{
                new Object[]{"d"},
                new Object[]{"e"},
            }),
            new ArrayBucket(new Object[][]{
                new Object[]{"y"},
                new Object[]{"z"},
            })
        )));

        consumeRows(pagingIterator, rows);
        assertThat(rows.size(), is(5));
        assertThat(TestingHelpers.printRows(rows), is("a\nb\nc\nd\ne\n"));

        pagingIterator.finish();
        consumeRows(pagingIterator, rows);
        assertThat(rows.size(), is(9));
        assertThat(TestingHelpers.printRows(rows), is("a\nb\nc\nd\ne\nx\ny\ny\nz\n"));
    }

    private void consumeRows(Iterator<Row> pagingIterator, List<Object[]> rows) {
        while (pagingIterator.hasNext()) {
            rows.add(pagingIterator.next().materialize());
        }
    }

    private void consumeSingleColumnRows(Iterator<Row> pagingIterator, List<Object> rows) {
        while (pagingIterator.hasNext()) {
            rows.add(pagingIterator.next().get(0));
        }
    }

    @Test
    public void testReplayReplaysCorrectly() throws Exception {
        SortedPagingIterator<Void, Row> pagingIterator = new SortedPagingIterator<>(ORDERING, true);
        pagingIterator.merge(numberedBuckets(Arrays.<Bucket>asList(
            new ArrayBucket(new Object[][]{
                new Object[]{"a"},
                new Object[]{"b"},
                new Object[]{"c"}}),
            new ArrayBucket(new Object[][]{
                new Object[]{"x"},
                new Object[]{"y"},
            }),
            new ArrayBucket(new Object[][]{
                new Object[]{"m"},
                new Object[]{"n"},
                new Object[]{"o"}
            })
        )));
        List<Object> rows = new ArrayList<>();
        consumeSingleColumnRows(pagingIterator, rows);

        pagingIterator.merge(numberedBuckets(Arrays.<Bucket>asList(
            new ArrayBucket(new Object[][]{
                new Object[]{"d"},
                new Object[]{"e"},
                new Object[]{"f"}}),
            new ArrayBucket(new Object[][]{
                new Object[]{"z"}
            })
        )));
        pagingIterator.finish();
        consumeSingleColumnRows(pagingIterator, rows);
        assertThat(rows.toString(), is("[a, b, c, d, e, f, m, n, o, x, y, z]"));

        List<Object> replayedRows = new ArrayList<>();
        consumeSingleColumnRows(pagingIterator.repeat().iterator(), replayedRows);
        assertThat(rows, is(replayedRows));
    }

    private Iterable<? extends KeyIterable<Void, Row>> numberedBuckets(List<Bucket> buckets) {
        return Iterables.transform(buckets, new Function<Bucket, KeyIterable<Void, Row>>() {

            @Nullable
            @Override
            public KeyIterable<Void, Row> apply(Bucket input) {
                return new KeyIterable<>(null, input);
            }
        });
    }
}