/**
 *    Copyright (C) 2021-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#pragma once

#include "mongo/db/pipeline/document_source_change_stream.h"
#include "mongo/db/pipeline/document_source_change_stream_gen.h"

namespace mongo::change_stream_legacy {

/**
 * Transforms a given user requested change stream 'spec' into a list of executable internal
 * pipeline stages.
 */
std::list<boost::intrusive_ptr<DocumentSource>> buildPipeline(
    const boost::intrusive_ptr<ExpressionContext>& expCtx, DocumentSourceChangeStreamSpec spec);

/**
 * Looks up and returns a pre-image document at the specified opTime in the oplog. Asserts that if
 * an oplog entry with the given opTime is found, it is a no-op entry with a valid non-empty
 * pre-image document.
 */
boost::optional<Document> legacyLookupPreImage(boost::intrusive_ptr<ExpressionContext> pExpCtx,
                                               const Document& preImageId);

/**
 * Maintains a document key cache. The cache will be used when the insert oplog entry does not
 * contain the documentKey. This can happen when reading an oplog entry written by an older version
 * of the server. Extracts the documentKey from the resume token on construction, and consults the
 * sharding catalog as needed when getDocumentKeyForOplogInsert is called.
 * TODO SERVER-64992: remove documentKey caching after branching for 6.0.
 */
class DocumentKeyCache {
public:
    using DocumentKeyCacheEntry = std::pair<std::vector<FieldPath>, bool>;

    DocumentKeyCache(const boost::intrusive_ptr<ExpressionContext>& expCtx,
                     const ResumeTokenData& token);

    Value getDocumentKeyForOplogInsert(Document oplogInsert);

private:
    DocumentKeyCacheEntry _collectDocumentKeyFieldsForHostedCollection(const NamespaceString& nss,
                                                                       const UUID& uuid) const;
    std::vector<FieldPath> _shardKeyToDocumentKeyFields(
        const std::vector<std::unique_ptr<FieldRef>>& keyPatternFields) const;

    boost::intrusive_ptr<ExpressionContext> _expCtx;
    std::map<UUID, DocumentKeyCacheEntry> _cache;
};

/**
 * Represents the change stream operation types that are NOT guarded behind the 'showExpandedEvents'
 * flag.
 */
static const std::set<StringData> kClassicOperationTypes =
    std::set<StringData>{DocumentSourceChangeStream::kUpdateOpType,
                         DocumentSourceChangeStream::kDeleteOpType,
                         DocumentSourceChangeStream::kReplaceOpType,
                         DocumentSourceChangeStream::kInsertOpType,
                         DocumentSourceChangeStream::kDropCollectionOpType,
                         DocumentSourceChangeStream::kRenameCollectionOpType,
                         DocumentSourceChangeStream::kDropDatabaseOpType,
                         DocumentSourceChangeStream::kInvalidateOpType,
                         DocumentSourceChangeStream::kReshardBeginOpType,
                         DocumentSourceChangeStream::kReshardDoneCatchUpOpType,
                         DocumentSourceChangeStream::kNewShardDetectedOpType};

}  // namespace mongo::change_stream_legacy