/*
 * 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 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 or the Server
 * Side Public License, v 1.
 */

package org.elasticsearch.index.mapper.murmur3;

import org.apache.lucene.index.DocValuesType;
import org.apache.lucene.index.IndexOptions;
import org.apache.lucene.index.IndexableField;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.hash.MurmurHash3;
import org.elasticsearch.index.fielddata.FieldDataContext;
import org.elasticsearch.index.fielddata.IndexFieldDataCache;
import org.elasticsearch.index.mapper.DocValueFetcher;
import org.elasticsearch.index.mapper.DocumentMapper;
import org.elasticsearch.index.mapper.MappedFieldType;
import org.elasticsearch.index.mapper.MapperService;
import org.elasticsearch.index.mapper.MapperTestCase;
import org.elasticsearch.index.mapper.ParsedDocument;
import org.elasticsearch.index.mapper.SourceToParse;
import org.elasticsearch.index.mapper.ValueFetcher;
import org.elasticsearch.index.query.SearchExecutionContext;
import org.elasticsearch.indices.breaker.NoneCircuitBreakerService;
import org.elasticsearch.plugin.mapper.MapperMurmur3Plugin;
import org.elasticsearch.plugins.Plugin;
import org.elasticsearch.search.lookup.Source;
import org.elasticsearch.search.lookup.SourceProvider;
import org.elasticsearch.xcontent.XContentBuilder;
import org.junit.AssumptionViolatedException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static java.util.stream.Collectors.toList;
import static org.hamcrest.Matchers.containsInAnyOrder;
import static org.hamcrest.Matchers.hasSize;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

public class Murmur3FieldMapperTests extends MapperTestCase {

    @Override
    protected Object getSampleValueForDocument() {
        return "value";
    }

    @Override
    protected Collection<? extends Plugin> getPlugins() {
        return List.of(new MapperMurmur3Plugin());
    }

    @Override
    protected void minimalMapping(XContentBuilder b) throws IOException {
        b.field("type", "murmur3");
    }

    @Override
    protected void registerParameters(ParameterChecker checker) throws IOException {
        checker.registerConflictCheck("store", b -> b.field("store", true));
    }

    public void testDefaults() throws Exception {
        DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
        ParsedDocument parsedDoc = mapper.parse(source(b -> b.field("field", "value")));
        List<IndexableField> fields = parsedDoc.rootDoc().getFields("field");
        assertNotNull(fields);
        assertThat(fields, hasSize(1));
        IndexableField field = fields.get(0);
        assertEquals(IndexOptions.NONE, field.fieldType().indexOptions());
        assertEquals(DocValuesType.SORTED_NUMERIC, field.fieldType().docValuesType());
    }

    @Override
    protected Object generateRandomInputValue(MappedFieldType ft) {
        return randomAlphaOfLength(randomIntBetween(0, 2048));
    }

    /**
     * Murmur3 transforms the input into a hash and only stores the hash, the native value fetcher pulling things from _source
     * should ensure that it hashes the value before it compares with the retrieved doc value
     */
    @Override
    protected void assertFetch(MapperService mapperService, String field, Object value, String format) throws IOException {
        MappedFieldType ft = mapperService.fieldType(field);
        MappedFieldType.FielddataOperation fdt = MappedFieldType.FielddataOperation.SEARCH;
        SourceToParse source = source(b -> b.field(ft.name(), value));
        ValueFetcher docValueFetcher = new DocValueFetcher(
            ft.docValueFormat(format, null),
            ft.fielddataBuilder(FieldDataContext.noRuntimeFields("test"))
                .build(new IndexFieldDataCache.None(), new NoneCircuitBreakerService())
        );
        SearchExecutionContext searchExecutionContext = mock(SearchExecutionContext.class);
        when(searchExecutionContext.isSourceEnabled()).thenReturn(true);
        when(searchExecutionContext.sourcePath(field)).thenReturn(Set.of(field));
        when(searchExecutionContext.getForField(ft, fdt)).thenAnswer(inv -> fieldDataLookup(mapperService).apply(ft, () -> {
            throw new UnsupportedOperationException();
        }, fdt));
        ValueFetcher nativeFetcher = ft.valueFetcher(searchExecutionContext, format);
        ParsedDocument doc = mapperService.documentMapper().parse(source);
        withLuceneIndex(mapperService, iw -> iw.addDocuments(doc.docs()), ir -> {
            Source s = SourceProvider.fromStoredFields().getSource(ir.leaves().get(0), 0);
            docValueFetcher.setNextReader(ir.leaves().get(0));
            nativeFetcher.setNextReader(ir.leaves().get(0));
            List<Object> fromDocValues = docValueFetcher.fetchValues(s, 0, new ArrayList<>());
            List<Object> fromNative = nativeFetcher.fetchValues(s, 0, new ArrayList<>());
            /*
             * The native fetcher returns String from source as Murmur3 transforms the input and stores the hash
             */
            fromNative = fromNative.stream().map(o -> {
                final BytesRef bytes = new BytesRef(o.toString());
                return MurmurHash3.hash128(bytes.bytes, bytes.offset, bytes.length, 0, new MurmurHash3.Hash128()).h1;
            }).collect(toList());

            if (dedupAfterFetch()) {
                fromNative = fromNative.stream().distinct().collect(Collectors.toList());
            }
            /*
             * Doc values sort according to something appropriate to the field
             * and the native fetchers usually don't sort. We're ok with this
             * difference. But we have to convince the test we're ok with it.
             */
            assertThat("fetching " + value, fromNative, containsInAnyOrder(fromDocValues.toArray()));
        });
    }

    @Override
    protected boolean supportsIgnoreMalformed() {
        return false;
    }

    @Override
    protected SyntheticSourceSupport syntheticSourceSupport(boolean ignoreMalformed) {
        throw new AssumptionViolatedException("not supported");
    }

    @Override
    protected IngestScriptSupport ingestScriptSupport() {
        throw new AssumptionViolatedException("not supported");
    }
}
