/*
 * 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.index.mapper;

import org.apache.lucene.document.Field;
import org.apache.lucene.document.LongField;
import org.apache.lucene.document.SortedDocValuesField;
import org.apache.lucene.document.SortedNumericDocValuesField;
import org.apache.lucene.document.StoredField;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.index.mapper.MapperService.MergeReason;
import org.elasticsearch.plugins.internal.XContentMeteringParserDecorator;
import org.elasticsearch.xcontent.XContentType;

import java.util.Collections;
import java.util.List;

/**
 * The result of parsing a document.
 */
public class ParsedDocument {

    private final Field version;

    private final String id;
    private final SeqNoFieldMapper.SequenceIDFields seqID;

    private final String routing;

    private final List<LuceneDocument> documents;

    private final long normalizedSize;

    private BytesReference source;
    private XContentType xContentType;
    private Mapping dynamicMappingsUpdate;

    /**
     * Create a no-op tombstone document
     * @param reason    the reason for the no-op
     */
    public static ParsedDocument noopTombstone(SeqNoFieldMapper.SeqNoIndexOptions seqNoIndexOptions, String reason) {
        LuceneDocument document = new LuceneDocument();
        var seqIdFields = SeqNoFieldMapper.SequenceIDFields.tombstone(seqNoIndexOptions);
        seqIdFields.addFields(document);
        Field versionField = VersionFieldMapper.versionField();
        document.add(versionField);
        // Store the reason of a noop as a raw string in the _source field
        final BytesRef byteRef = new BytesRef(reason);
        document.add(new StoredField(SourceFieldMapper.NAME, byteRef.bytes, byteRef.offset, byteRef.length));
        return new ParsedDocument(
            versionField,
            seqIdFields,
            "",
            null,
            Collections.singletonList(document),
            new BytesArray("{}"),
            XContentType.JSON,
            null,
            XContentMeteringParserDecorator.UNKNOWN_SIZE
        );
    }

    /**
     * Create a delete tombstone document, which will be used in soft-update methods.
     * The returned document consists only _uid, _seqno, _term and _version fields; other metadata fields are excluded.
     * @param id                the id of the deleted document
     */
    // used by tests
    public static ParsedDocument deleteTombstone(SeqNoFieldMapper.SeqNoIndexOptions seqNoIndexOptions, String id) {
        return deleteTombstone(seqNoIndexOptions, false /* ignored */, false, id, null /* ignored */);
    }

    /**
     * Create a delete tombstone document, which will be used in soft-update methods.
     * The returned document consists only _uid, _seqno, _term and _version fields; other metadata fields are excluded.
     * @param useSyntheticId    whether the id is synthetic or not
     * @param id                the id of the deleted document
     */
    public static ParsedDocument deleteTombstone(
        SeqNoFieldMapper.SeqNoIndexOptions seqNoIndexOptions,
        boolean useDocValuesSkipper,
        boolean useSyntheticId,
        String id,
        BytesRef uid
    ) {
        LuceneDocument document = new LuceneDocument();
        SeqNoFieldMapper.SequenceIDFields seqIdFields = SeqNoFieldMapper.SequenceIDFields.tombstone(seqNoIndexOptions);
        seqIdFields.addFields(document);
        Field versionField = VersionFieldMapper.versionField();
        document.add(versionField);
        if (useSyntheticId) {
            // Use a synthetic _id field which is not indexed nor stored
            document.add(IdFieldMapper.syntheticIdField(uid));

            // Add doc values fields that are used to synthesize the synthetic _id.
            // Note: It is not strictly required for tombstones documents but we decided to add them so that iterating and seeking synthetic
            // _id terms over tombstones also work as if a regular _id field was present.
            var timeSeriesId = TsidExtractingIdFieldMapper.extractTimeSeriesIdFromSyntheticId(uid);
            var timestamp = TsidExtractingIdFieldMapper.extractTimestampFromSyntheticId(uid);
            int routingHash = TsidExtractingIdFieldMapper.extractRoutingHashFromSyntheticId(uid);

            if (useDocValuesSkipper) {
                document.add(SortedDocValuesField.indexedField(TimeSeriesIdFieldMapper.NAME, timeSeriesId));
                document.add(SortedNumericDocValuesField.indexedField("@timestamp", timestamp));
            } else {
                document.add(new SortedDocValuesField(TimeSeriesIdFieldMapper.NAME, timeSeriesId));
                document.add(new LongField("@timestamp", timestamp, Field.Store.NO));
            }
            var field = new SortedDocValuesField(
                TimeSeriesRoutingHashFieldMapper.NAME,
                Uid.encodeId(TimeSeriesRoutingHashFieldMapper.encode(routingHash))
            );
            document.add(field);

        } else {
            // Use standard _id field (indexed and stored, some indices also trim the stored field at some point)
            document.add(IdFieldMapper.standardIdField(id));
        }
        return new ParsedDocument(
            versionField,
            seqIdFields,
            id,
            null,
            Collections.singletonList(document),
            new BytesArray("{}"),
            XContentType.JSON,
            null,
            XContentMeteringParserDecorator.UNKNOWN_SIZE
        );
    }

    public ParsedDocument(
        Field version,
        SeqNoFieldMapper.SequenceIDFields seqID,
        String id,
        String routing,
        List<LuceneDocument> documents,
        BytesReference source,
        XContentType xContentType,
        Mapping dynamicMappingsUpdate,
        long normalizedSize
    ) {
        this.version = version;
        this.seqID = seqID;
        this.id = id;
        this.routing = routing;
        this.documents = documents;
        this.source = source;
        this.dynamicMappingsUpdate = dynamicMappingsUpdate;
        this.xContentType = xContentType;
        this.normalizedSize = normalizedSize;
    }

    public String id() {
        return this.id;
    }

    public Field version() {
        return version;
    }

    /**
     * Update the values of the {@code _seq_no} and {@code primary_term} fields
     * to the specified value. Called in the engine long after parsing.
     */
    public void updateSeqID(long seqNo, long primaryTerm) {
        seqID.set(seqNo, primaryTerm);
    }

    public String routing() {
        return this.routing;
    }

    public LuceneDocument rootDoc() {
        return documents.get(documents.size() - 1);
    }

    public List<LuceneDocument> docs() {
        return this.documents;
    }

    public BytesReference source() {
        return this.source;
    }

    public XContentType getXContentType() {
        return this.xContentType;
    }

    public void setSource(BytesReference source, XContentType xContentType) {
        this.source = source;
        this.xContentType = xContentType;
    }

    /**
     * Return dynamic updates to mappings or {@code null} if there were no
     * updates to the mappings.
     */
    public Mapping dynamicMappingsUpdate() {
        return dynamicMappingsUpdate;
    }

    public void addDynamicMappingsUpdate(Mapping update) {
        if (dynamicMappingsUpdate == null) {
            dynamicMappingsUpdate = update;
        } else {
            dynamicMappingsUpdate = dynamicMappingsUpdate.merge(update, MergeReason.MAPPING_AUTO_UPDATE, Long.MAX_VALUE);
        }
    }

    @Override
    public String toString() {
        return "Document id[" + id + "] doc [" + documents + ']';
    }

    public String documentDescription() {
        return "id";
    }

    public long getNormalizedSize() {
        return normalizedSize;
    }
}