/*
 * 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.deps.lucene;

import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.FieldType;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.MultiTermQuery;
import org.apache.lucene.search.PrefixQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.vectorhighlight.FastVectorHighlighter;
import org.apache.lucene.store.ByteBuffersDirectory;
import org.apache.lucene.store.Directory;
import org.elasticsearch.common.lucene.Lucene;
import org.elasticsearch.core.IOUtils;
import org.elasticsearch.lucene.search.vectorhighlight.CustomFieldQuery;
import org.elasticsearch.test.ESTestCase;

import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.notNullValue;
import static org.hamcrest.Matchers.nullValue;

public class VectorHighlighterTests extends ESTestCase {
    public void testVectorHighlighter() throws Exception {
        Directory dir = new ByteBuffersDirectory();
        IndexWriter indexWriter = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));

        Document document = new Document();
        document.add(new TextField("_id", "1", Field.Store.YES));
        FieldType vectorsType = new FieldType(TextField.TYPE_STORED);
        vectorsType.setStoreTermVectors(true);
        vectorsType.setStoreTermVectorPositions(true);
        vectorsType.setStoreTermVectorOffsets(true);
        document.add(new Field("content", "the big bad dog", vectorsType));
        indexWriter.addDocument(document);

        IndexReader reader = DirectoryReader.open(indexWriter);
        IndexSearcher searcher = newSearcher(reader);
        TopDocs topDocs = searcher.search(new TermQuery(new Term("_id", "1")), 1);

        assertThat(topDocs.totalHits.value(), equalTo(1L));

        FastVectorHighlighter highlighter = new FastVectorHighlighter();
        String fragment = highlighter.getBestFragment(
            highlighter.getFieldQuery(new TermQuery(new Term("content", "bad"))),
            searcher.getIndexReader(),
            topDocs.scoreDocs[0].doc,
            "content",
            30
        );
        assertThat(fragment, notNullValue());
        assertThat(fragment, equalTo("the big <b>bad</b> dog"));
        IOUtils.close(reader, indexWriter, dir);
    }

    public void testVectorHighlighterPrefixQuery() throws Exception {
        Directory dir = new ByteBuffersDirectory();
        IndexWriter indexWriter = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));

        Document document = new Document();
        document.add(new TextField("_id", "1", Field.Store.YES));
        FieldType vectorsType = new FieldType(TextField.TYPE_STORED);
        vectorsType.setStoreTermVectors(true);
        vectorsType.setStoreTermVectorPositions(true);
        vectorsType.setStoreTermVectorOffsets(true);
        document.add(new Field("content", "the big bad dog", vectorsType));
        indexWriter.addDocument(document);

        IndexReader indexReader = DirectoryReader.open(indexWriter);
        IndexSearcher searcher = newSearcher(indexReader);
        IndexReader reader = searcher.getIndexReader();
        TopDocs topDocs = searcher.search(new TermQuery(new Term("_id", "1")), 1);

        assertThat(topDocs.totalHits.value(), equalTo(1L));

        FastVectorHighlighter highlighter = new FastVectorHighlighter();

        PrefixQuery prefixQuery = new PrefixQuery(new Term("content", "ba"));
        assertThat(
            prefixQuery.getRewriteMethod().getClass().getName(),
            equalTo(PrefixQuery.CONSTANT_SCORE_BLENDED_REWRITE.getClass().getName())
        );
        String fragment = highlighter.getBestFragment(
            highlighter.getFieldQuery(prefixQuery),
            reader,
            topDocs.scoreDocs[0].doc,
            "content",
            30
        );
        assertThat(fragment, nullValue());
        prefixQuery = new PrefixQuery(new Term("content", "ba"), MultiTermQuery.SCORING_BOOLEAN_REWRITE);
        Query rewriteQuery = prefixQuery.rewrite(searcher);
        fragment = highlighter.getBestFragment(highlighter.getFieldQuery(rewriteQuery), reader, topDocs.scoreDocs[0].doc, "content", 30);
        assertThat(fragment, notNullValue());

        // now check with the custom field query
        prefixQuery = new PrefixQuery(new Term("content", "ba"));
        assertThat(
            prefixQuery.getRewriteMethod().getClass().getName(),
            equalTo(PrefixQuery.CONSTANT_SCORE_BLENDED_REWRITE.getClass().getName())
        );
        fragment = highlighter.getBestFragment(
            new CustomFieldQuery(prefixQuery, reader, highlighter),
            reader,
            topDocs.scoreDocs[0].doc,
            "content",
            30
        );
        assertThat(fragment, notNullValue());
        IOUtils.close(indexReader, indexWriter, dir);
    }

    public void testVectorHighlighterNoStore() throws Exception {
        Directory dir = new ByteBuffersDirectory();
        IndexWriter indexWriter = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));

        Document document = new Document();
        document.add(new TextField("_id", "1", Field.Store.YES));
        FieldType vectorsType = new FieldType(TextField.TYPE_NOT_STORED);
        vectorsType.setStoreTermVectors(true);
        vectorsType.setStoreTermVectorPositions(true);
        vectorsType.setStoreTermVectorOffsets(true);
        document.add(new Field("content", "the big bad dog", vectorsType));
        indexWriter.addDocument(document);

        IndexReader reader = DirectoryReader.open(indexWriter);
        IndexSearcher searcher = newSearcher(reader);
        TopDocs topDocs = searcher.search(new TermQuery(new Term("_id", "1")), 1);

        assertThat(topDocs.totalHits.value(), equalTo(1L));

        FastVectorHighlighter highlighter = new FastVectorHighlighter();
        String fragment = highlighter.getBestFragment(
            highlighter.getFieldQuery(new TermQuery(new Term("content", "bad"))),
            searcher.getIndexReader(),
            topDocs.scoreDocs[0].doc,
            "content",
            30
        );
        assertThat(fragment, nullValue());
        IOUtils.close(reader, indexWriter, dir);
    }

    public void testVectorHighlighterNoTermVector() throws Exception {
        Directory dir = new ByteBuffersDirectory();
        IndexWriter indexWriter = new IndexWriter(dir, new IndexWriterConfig(Lucene.STANDARD_ANALYZER));

        Document document = new Document();
        document.add(new TextField("_id", "1", Field.Store.YES));
        document.add(new TextField("content", "the big bad dog", Field.Store.YES));
        indexWriter.addDocument(document);

        IndexReader reader = DirectoryReader.open(indexWriter);
        IndexSearcher searcher = newSearcher(reader);
        TopDocs topDocs = searcher.search(new TermQuery(new Term("_id", "1")), 1);

        assertThat(topDocs.totalHits.value(), equalTo(1L));

        FastVectorHighlighter highlighter = new FastVectorHighlighter();
        String fragment = highlighter.getBestFragment(
            highlighter.getFieldQuery(new TermQuery(new Term("content", "bad"))),
            searcher.getIndexReader(),
            topDocs.scoreDocs[0].doc,
            "content",
            30
        );
        assertThat(fragment, nullValue());
        IOUtils.close(reader, indexWriter, dir);
    }
}