/**
 *    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.
 */

#include "mongo/platform/basic.h"

#include "mongo/db/command_can_run_here.h"

#include "mongo/client/read_preference.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/util/assert_util.h"

namespace mongo {

bool commandCanRunHere(OperationContext* opCtx,
                       const DatabaseName& dbName,
                       const Command* command,
                       bool inMultiDocumentTransaction) {
    auto replCoord = repl::ReplicationCoordinator::get(opCtx);
    if (replCoord->canAcceptWritesForDatabase_UNSAFE(opCtx, dbName))
        return true;  // primary: always ok
    if (!opCtx->writesAreReplicated())
        return true;  // standalone: always ok
    if (inMultiDocumentTransaction)
        return false;  // Transactions are not allowed on secondaries.
    switch (command->secondaryAllowed(opCtx->getServiceContext())) {
        case Command::AllowedOnSecondary::kAlways:
            return true;
        case Command::AllowedOnSecondary::kNever:
            return false;
        case Command::AllowedOnSecondary::kOptIn:
            // Did the user opt in?
            return ReadPreferenceSetting::get(opCtx).canRunOnSecondary();
    }
    MONGO_UNREACHABLE;
}

}  // namespace mongo