/**
 *    Copyright (C) 2016 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.
 */

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kSharding

#include "mongo/platform/basic.h"

#include "mongo/db/audit.h"
#include "mongo/db/auth/action_type.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/auth/privilege.h"
#include "mongo/db/commands.h"
#include "mongo/db/commands/feature_compatibility_version.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/repl/repl_set_config.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/s/catalog/sharding_catalog_manager.h"
#include "mongo/s/catalog/type_shard.h"
#include "mongo/s/grid.h"
#include "mongo/s/request_types/add_shard_request_type.h"
#include "mongo/util/log.h"
#include "mongo/util/mongoutils/str.h"

namespace mongo {
namespace {

using std::string;

const long long kMaxSizeMBDefault = 0;

/**
 * Internal sharding command run on config servers to add a shard to the cluster.
 */
class ConfigSvrAddShardCommand : public BasicCommand {
public:
    ConfigSvrAddShardCommand() : BasicCommand("_configsvrAddShard") {}

    void help(std::stringstream& help) const override {
        help << "Internal command, which is exported by the sharding config server. Do not call "
                "directly. Validates and adds a new shard to the cluster.";
    }

    bool slaveOk() const override {
        return false;
    }

    bool adminOnly() const override {
        return true;
    }

    bool supportsWriteConcern(const BSONObj& cmd) const override {
        return true;
    }

    Status checkAuthForCommand(Client* client,
                               const std::string& dbname,
                               const BSONObj& cmdObj) override {
        if (!AuthorizationSession::get(client)->isAuthorizedForActionsOnResource(
                ResourcePattern::forClusterResource(), ActionType::internal)) {
            return Status(ErrorCodes::Unauthorized, "Unauthorized");
        }
        return Status::OK();
    }

    bool run(OperationContext* opCtx,
             const std::string& unusedDbName,
             const BSONObj& cmdObj,
             BSONObjBuilder& result) override {
        if (serverGlobalParams.clusterRole != ClusterRole::ConfigServer) {
            return appendCommandStatus(
                result,
                Status(ErrorCodes::IllegalOperation,
                       "_configsvrAddShard can only be run on config servers"));
        }

        // Do not allow adding shards while a featureCompatibilityVersion upgrade or downgrade is in
        // progress (see SERVER-31231 for details).
        Lock::ExclusiveLock lk(opCtx->lockState(), FeatureCompatibilityVersion::fcvLock);

        auto swParsedRequest = AddShardRequest::parseFromConfigCommand(cmdObj);
        if (!swParsedRequest.isOK()) {
            return appendCommandStatus(result, swParsedRequest.getStatus());
        }
        auto parsedRequest = std::move(swParsedRequest.getValue());

        auto replCoord = repl::ReplicationCoordinator::get(opCtx);
        auto rsConfig = replCoord->getConfig();

        auto validationStatus = parsedRequest.validate(rsConfig.isLocalHostAllowed());
        if (!validationStatus.isOK()) {
            return appendCommandStatus(result, validationStatus);
        }

        uassert(ErrorCodes::InvalidOptions,
                str::stream() << "addShard must be called with majority writeConcern, got "
                              << cmdObj,
                opCtx->getWriteConcern().wMode == WriteConcernOptions::kMajority);

        audit::logAddShard(Client::getCurrent(),
                           parsedRequest.hasName() ? parsedRequest.getName() : "",
                           parsedRequest.getConnString().toString(),
                           parsedRequest.hasMaxSize() ? parsedRequest.getMaxSize()
                                                      : kMaxSizeMBDefault);

        StatusWith<string> addShardResult = ShardingCatalogManager::get(opCtx)->addShard(
            opCtx,
            parsedRequest.hasName() ? &parsedRequest.getName() : nullptr,
            parsedRequest.getConnString(),
            parsedRequest.hasMaxSize() ? parsedRequest.getMaxSize() : kMaxSizeMBDefault);

        if (!addShardResult.isOK()) {
            log() << "addShard request '" << parsedRequest << "'"
                  << "failed" << causedBy(addShardResult.getStatus());
            return appendCommandStatus(result, addShardResult.getStatus());
        }

        result << "shardAdded" << addShardResult.getValue();

        return true;
    }
} configsvrAddShardCmd;

}  // namespace
}  // namespace mongo
