/**
 * Copyright (C) 2017 MongoDB Inc.
 *
 * This program is free software: you can redistribute it and/or  modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * 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
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * 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 GNU Affero General 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/initialize_operation_session_info.h"

#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/logical_session_cache.h"
#include "mongo/db/logical_session_id_helpers.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/server_parameters.h"

namespace mongo {

boost::optional<OperationSessionInfoFromClient> initializeOperationSessionInfo(
    OperationContext* opCtx,
    const BSONObj& requestBody,
    bool requiresAuth,
    bool isReplSetMemberOrMongos,
    bool supportsDocLocking,
    bool supportsRecoverToStableTimestamp) {
    auto osi = OperationSessionInfoFromClient::parse("OperationSessionInfo"_sd, requestBody);

    if (opCtx->getClient()->isInDirectClient()) {
        uassert(50891,
                "Invalid to set operation session info in a direct client",
                !osi.getSessionId() && !osi.getTxnNumber() && !osi.getAutocommit() &&
                    !osi.getStartTransaction());
    }

    if (!requiresAuth) {
        uassert(ErrorCodes::OperationNotSupportedInTransaction,
                "This command is not supported in transactions",
                !osi.getAutocommit());
        uassert(
            50889, "It is illegal to provide a txnNumber for this command", !osi.getTxnNumber());
        return boost::none;
    }

    {
        // If we're using the localhost bypass, and the client hasn't authenticated,
        // logical sessions are disabled. A client may authenticate as the __sytem user,
        // or as an externally authorized user.
        AuthorizationSession* authSession = AuthorizationSession::get(opCtx->getClient());
        if (authSession && authSession->isUsingLocalhostBypass() &&
            !authSession->isAuthenticated()) {
            return boost::none;
        }
    }

    if (osi.getSessionId()) {
        stdx::lock_guard<Client> lk(*opCtx->getClient());

        auto lsc = LogicalSessionCache::get(opCtx->getServiceContext());
        if (!lsc) {
            // Ignore session information if the logical session cache has not been set up, e.g. on
            // the embedded version of mongod.
            return boost::none;
        }

        opCtx->setLogicalSessionId(makeLogicalSessionId(osi.getSessionId().get(), opCtx));
        uassertStatusOK(lsc->vivify(opCtx, opCtx->getLogicalSessionId().get()));
    } else {
        uassert(ErrorCodes::InvalidOptions,
                "Transaction number requires a session ID to also be specified",
                !osi.getTxnNumber());
    }

    if (osi.getTxnNumber()) {
        invariant(osi.getSessionId());
        stdx::lock_guard<Client> lk(*opCtx->getClient());

        uassert(ErrorCodes::IllegalOperation,
                "Transaction numbers are only allowed on a replica set member or mongos",
                isReplSetMemberOrMongos);
        uassert(ErrorCodes::IllegalOperation,
                "Transaction numbers are only allowed on storage engines that support "
                "document-level locking",
                supportsDocLocking);
        uassert(ErrorCodes::InvalidOptions,
                "Transaction number cannot be negative",
                *osi.getTxnNumber() >= 0);

        opCtx->setTxnNumber(*osi.getTxnNumber());
    } else {
        uassert(ErrorCodes::InvalidOptions,
                "'autocommit' field requires a transaction number to also be specified",
                !osi.getAutocommit());
    }

    if (osi.getAutocommit()) {
        invariant(osi.getTxnNumber());
        uassert(ErrorCodes::InvalidOptions,
                "Specifying autocommit=true is not allowed.",
                !osi.getAutocommit().value());

        uassert(ErrorCodes::IllegalOperation,
                "Multi-document transactions are only allowed on storage engines that support "
                "recover to stable timestamp.",
                supportsRecoverToStableTimestamp);
    } else {
        uassert(ErrorCodes::InvalidOptions,
                "'startTransaction' field requires 'autocommit' field to also be specified",
                !osi.getStartTransaction());
    }

    if (osi.getStartTransaction()) {
        invariant(osi.getAutocommit());
        uassert(ErrorCodes::InvalidOptions,
                "Specifying startTransaction=false is not allowed.",
                osi.getStartTransaction().value());
    }

    return osi;
}

}  // namespace mongo