/**
 *    Copyright (C) 2018-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

/**
 * copy a database (export/import basically)
 */

#include <string>
#include <vector>

#include "mongo/client/dbclient_base.h"
#include "mongo/db/catalog/collection_options.h"

namespace mongo {

struct CloneOptions;
class DBClientBase;
class NamespaceString;
class OperationContext;


class Cloner {
    Cloner(const Cloner&) = delete;
    Cloner& operator=(const Cloner&) = delete;

public:
    Cloner();

    void setConnection(std::unique_ptr<DBClientBase> c) {
        _conn = std::move(c);
    }

    /**
     * Copies an entire database from the specified host.
     * clonedColls: when not-null, the function will return with this populated with a list of
     *              the collections that were cloned.
     * collectionsToClone: When opts.createCollections is false, this list reflects the collections
     *              that are cloned.  When opts.createCollections is true, this parameter is
     *              ignored and the collection list is fetched from the remote via _conn.
     */
    Status copyDb(OperationContext* opCtx,
                  const std::string& toDBName,
                  const std::string& masterHost,
                  const CloneOptions& opts,
                  std::set<std::string>* clonedColls,
                  std::vector<BSONObj> collectionsToClone = std::vector<BSONObj>());

    /**
     * Copies a collection. The optionsParser indicates how to parse the collection options. If
     * 'parseForCommand' is provided, then the UUID is ignored and a new UUID is generated. If
     * 'parseForStorage' is provided, then the UUID will be preserved and parsed out of the
     * options.
     */
    bool copyCollection(OperationContext* opCtx,
                        const std::string& ns,
                        const BSONObj& query,
                        std::string& errmsg,
                        bool copyIndexes,
                        CollectionOptions::ParseKind optionsParser);

    // Filters a database's collection list and removes collections that should not be cloned.
    // CloneOptions should be populated with a fromDB and a list of collections to ignore, which
    // will be filtered out.
    StatusWith<std::vector<BSONObj>> filterCollectionsForClone(
        const CloneOptions& opts, const std::list<BSONObj>& initialCollections);

    struct CreateCollectionParams {
        std::string collectionName;
        BSONObj collectionInfo;
        BSONObj idIndexSpec;
        bool shardedColl = false;
    };

    // Executes 'createCollection' for each collection described in 'createCollectionParams', in
    // 'dbName'.
    Status createCollectionsForDb(OperationContext* opCtx,
                                  const std::vector<CreateCollectionParams>& createCollectionParams,
                                  const std::string& dbName,
                                  const CloneOptions& opts);

    /*
     * Returns the _id index spec from 'indexSpecs', or an empty BSONObj if none is found.
     */
    static BSONObj getIdIndexSpec(const std::list<BSONObj>& indexSpecs);

private:
    void copy(OperationContext* opCtx,
              const std::string& toDBName,
              const NamespaceString& from_ns,
              const BSONObj& from_opts,
              const BSONObj& from_id_index,
              const NamespaceString& to_ns,
              const CloneOptions& opts,
              Query q);

    void copyIndexes(OperationContext* opCtx,
                     const std::string& toDBName,
                     const NamespaceString& from_ns,
                     const BSONObj& from_opts,
                     const std::list<BSONObj>& from_indexes,
                     const NamespaceString& to_ns);

    struct Fun;
    std::unique_ptr<DBClientBase> _conn;
};

/**
 *  slaveOk     - if true it is ok if the source of the data is !ismaster.
 *  useReplAuth - use the credentials we normally use as a replication slave for the cloning
 *  createCollections - When 'true', will fetch a list of collections from the remote and create
 *                them.  When 'false', assumes collections have already been created ahead of time.
 */
struct CloneOptions {
    std::string fromDB;
    std::set<std::string> shardedColls;

    bool slaveOk = false;
    bool useReplAuth = false;

    bool syncData = true;
    bool syncIndexes = true;
    bool createCollections = true;
};

}  // namespace mongo