/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */
package org.elasticsearch.common.lucene.uid;

import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.LongPoint;
import org.apache.lucene.document.NumericDocValuesField;
import org.apache.lucene.document.StringField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.store.Directory;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.cluster.metadata.DataStream;
import org.elasticsearch.common.lucene.Lucene;
import org.elasticsearch.common.lucene.index.ElasticsearchDirectoryReader;
import org.elasticsearch.index.mapper.IdFieldMapper;
import org.elasticsearch.index.mapper.SeqNoFieldMapper;
import org.elasticsearch.index.mapper.VersionFieldMapper;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.test.ESTestCase;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import static org.elasticsearch.common.lucene.uid.VersionsAndSeqNoResolver.timeSeriesLoadDocIdAndVersion;
import static org.elasticsearch.index.mapper.TsidExtractingIdFieldMapper.createId;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.notNullValue;
import static org.hamcrest.Matchers.nullValue;

public class VersionsTests extends ESTestCase {

    public static DirectoryReader reopen(DirectoryReader reader) throws IOException {
        return reopen(reader, true);
    }

    public static DirectoryReader reopen(DirectoryReader reader, boolean newReaderExpected) throws IOException {
        DirectoryReader newReader = DirectoryReader.openIfChanged(reader);
        if (newReader != null) {
            reader.close();
        } else {
            assertFalse(newReaderExpected);
        }
        return newReader;
    }

    public void testVersions() throws Exception {
        Directory dir = newDirectory();
        IndexWriter writer = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));
        DirectoryReader directoryReader = ElasticsearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "_na_", 1));
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()), nullValue());

        Document doc = new Document();
        doc.add(new StringField(IdFieldMapper.NAME, "1", Field.Store.YES));
        doc.add(new NumericDocValuesField(VersionFieldMapper.NAME, 1));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, randomNonNegativeLong()));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, randomLongBetween(1, Long.MAX_VALUE)));
        writer.updateDocument(new Term(IdFieldMapper.NAME, "1"), doc);
        directoryReader = reopen(directoryReader);
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()).version, equalTo(1L));

        doc = new Document();
        Field uid = new StringField(IdFieldMapper.NAME, "1", Field.Store.YES);
        Field version = new NumericDocValuesField(VersionFieldMapper.NAME, 2);
        doc.add(uid);
        doc.add(version);
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, randomNonNegativeLong()));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, randomLongBetween(1, Long.MAX_VALUE)));
        writer.updateDocument(new Term(IdFieldMapper.NAME, "1"), doc);
        directoryReader = reopen(directoryReader);
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()).version, equalTo(2L));

        // test reuse of uid field
        doc = new Document();
        version.setLongValue(3);
        doc.add(uid);
        doc.add(version);
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, randomNonNegativeLong()));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, randomLongBetween(1, Long.MAX_VALUE)));
        writer.updateDocument(new Term(IdFieldMapper.NAME, "1"), doc);

        directoryReader = reopen(directoryReader);
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()).version, equalTo(3L));

        writer.deleteDocuments(new Term(IdFieldMapper.NAME, "1"));
        directoryReader = reopen(directoryReader);
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()), nullValue());
        directoryReader.close();
        writer.close();
        dir.close();
    }

    public void testNestedDocuments() throws IOException {
        Directory dir = newDirectory();
        IndexWriter writer = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));

        List<Document> docs = new ArrayList<>();
        for (int i = 0; i < 4; ++i) {
            // Nested
            Document doc = new Document();
            doc.add(new StringField(IdFieldMapper.NAME, "1", Field.Store.NO));
            docs.add(doc);
        }
        // Root
        Document doc = new Document();
        doc.add(new StringField(IdFieldMapper.NAME, "1", Field.Store.YES));
        NumericDocValuesField version = new NumericDocValuesField(VersionFieldMapper.NAME, 5L);
        doc.add(version);
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, randomNonNegativeLong()));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, randomLongBetween(1, Long.MAX_VALUE)));
        docs.add(doc);

        writer.updateDocuments(new Term(IdFieldMapper.NAME, "1"), docs);
        DirectoryReader directoryReader = ElasticsearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "_na_", 1));
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()).version, equalTo(5L));

        version.setLongValue(6L);
        writer.updateDocuments(new Term(IdFieldMapper.NAME, "1"), docs);
        version.setLongValue(7L);
        writer.updateDocuments(new Term(IdFieldMapper.NAME, "1"), docs);
        directoryReader = reopen(directoryReader);
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()).version, equalTo(7L));

        writer.deleteDocuments(new Term(IdFieldMapper.NAME, "1"));
        directoryReader = reopen(directoryReader);
        assertThat(timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), randomBoolean()), nullValue());
        directoryReader.close();
        writer.close();
        dir.close();
    }

    /** Test that version map cache works, is evicted on close, etc */
    public void testCache() throws Exception {
        int size = VersionsAndSeqNoResolver.lookupStates.size();

        Directory dir = newDirectory();
        IndexWriter writer = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));
        Document doc = new Document();
        doc.add(new StringField(IdFieldMapper.NAME, "6", Field.Store.YES));
        doc.add(new NumericDocValuesField(VersionFieldMapper.NAME, 87));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, randomNonNegativeLong()));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, randomLongBetween(1, Long.MAX_VALUE)));
        writer.addDocument(doc);
        DirectoryReader reader = DirectoryReader.open(writer);
        // should increase cache size by 1
        assertEquals(87, timeSeriesLoadDocIdAndVersion(reader, new BytesRef("6"), randomBoolean()).version);
        assertEquals(size + 1, VersionsAndSeqNoResolver.lookupStates.size());
        // should be cache hit
        assertEquals(87, timeSeriesLoadDocIdAndVersion(reader, new BytesRef("6"), randomBoolean()).version);
        assertEquals(size + 1, VersionsAndSeqNoResolver.lookupStates.size());

        reader.close();
        writer.close();
        // core should be evicted from the map
        assertEquals(size, VersionsAndSeqNoResolver.lookupStates.size());
        dir.close();
    }

    /** Test that version map cache behaves properly with a filtered reader */
    public void testCacheFilterReader() throws Exception {
        int size = VersionsAndSeqNoResolver.lookupStates.size();

        Directory dir = newDirectory();
        IndexWriter writer = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));
        Document doc = new Document();
        doc.add(new StringField(IdFieldMapper.NAME, "6", Field.Store.YES));
        doc.add(new NumericDocValuesField(VersionFieldMapper.NAME, 87));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, randomNonNegativeLong()));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, randomLongBetween(1, Long.MAX_VALUE)));
        writer.addDocument(doc);
        DirectoryReader reader = DirectoryReader.open(writer);
        assertEquals(87, timeSeriesLoadDocIdAndVersion(reader, new BytesRef("6"), randomBoolean()).version);
        assertEquals(size + 1, VersionsAndSeqNoResolver.lookupStates.size());
        // now wrap the reader
        DirectoryReader wrapped = ElasticsearchDirectoryReader.wrap(reader, new ShardId("bogus", "_na_", 5));
        assertEquals(87, timeSeriesLoadDocIdAndVersion(wrapped, new BytesRef("6"), randomBoolean()).version);
        // same size map: core cache key is shared
        assertEquals(size + 1, VersionsAndSeqNoResolver.lookupStates.size());

        reader.close();
        writer.close();
        // core should be evicted from the map
        assertEquals(size, VersionsAndSeqNoResolver.lookupStates.size());
        dir.close();
    }

    public void testTimeSeriesLoadDocIdAndVersion() throws Exception {
        Directory dir = newDirectory();
        IndexWriter writer = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));
        DirectoryReader directoryReader = ElasticsearchDirectoryReader.wrap(DirectoryReader.open(writer), new ShardId("foo", "_na_", 1));
        String id = createTSDBId(1000L);
        assertThat(
            VersionsAndSeqNoResolver.timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), id, randomBoolean()),
            nullValue()
        );

        Document doc = new Document();
        doc.add(new StringField(IdFieldMapper.NAME, "1", Field.Store.YES));
        doc.add(new LongPoint(DataStream.TIMESTAMP_FIELD_NAME, 1_000));
        doc.add(new NumericDocValuesField(VersionFieldMapper.NAME, 1));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, 0L));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, 1L));
        writer.updateDocument(new Term(IdFieldMapper.NAME, "1"), doc);

        doc = new Document();
        doc.add(new StringField(IdFieldMapper.NAME, "2", Field.Store.YES));
        doc.add(new LongPoint(DataStream.TIMESTAMP_FIELD_NAME, 10_000));
        doc.add(new NumericDocValuesField(VersionFieldMapper.NAME, 1));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.NAME, 0L));
        doc.add(new NumericDocValuesField(SeqNoFieldMapper.PRIMARY_TERM_NAME, 1L));
        writer.updateDocument(new Term(IdFieldMapper.NAME, "2"), doc);
        directoryReader = reopen(directoryReader);

        id = createTSDBId(randomLongBetween(1000, 10000));
        assertThat(VersionsAndSeqNoResolver.timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), id, true), notNullValue());
        assertThat(VersionsAndSeqNoResolver.timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("2"), id, true), notNullValue());
        id = createTSDBId(randomBoolean() ? randomLongBetween(0, 999) : randomLongBetween(10001, Long.MAX_VALUE));
        assertThat(VersionsAndSeqNoResolver.timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("1"), id, true), nullValue());
        assertThat(VersionsAndSeqNoResolver.timeSeriesLoadDocIdAndVersion(directoryReader, new BytesRef("2"), id, true), nullValue());

        directoryReader.close();
        writer.close();
        dir.close();
    }

    private static String createTSDBId(long timestamp) {
        return createId(randomInt(), new BytesRef("tsid"), timestamp);
    }
}