/**
 * 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 <vector>

#include "mongo/base/init.h"
#include "mongo/db/commands.h"
#include "mongo/executor/async_multicaster.h"
#include "mongo/executor/task_executor_pool.h"
#include "mongo/s/catalog/sharding_catalog_client.h"
#include "mongo/s/catalog/type_shard.h"
#include "mongo/s/client/shard_registry.h"
#include "mongo/s/commands/cluster_multicast_gen.h"
#include "mongo/s/grid.h"

namespace mongo {
namespace {

std::vector<HostAndPort> getAllClusterHosts(OperationContext* opCtx) {
    auto registry = Grid::get(opCtx)->shardRegistry();

    std::vector<ShardId> shardIds;
    registry->getAllShardIds(&shardIds);

    std::vector<HostAndPort> servers;
    for (const auto& shardId : shardIds) {
        auto shard = uassertStatusOK(registry->getShard(opCtx, shardId));

        auto cs = shard->getConnString();
        for (auto&& host : cs.getServers()) {
            servers.emplace_back(host);
        }
    }

    return servers;
}

class MulticastCmd : public BasicCommand {
public:
    MulticastCmd() : BasicCommand("multicast") {}

    bool slaveOk() const override {
        return true;
    }

    bool adminOnly() const override {
        return true;
    }


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

    void help(std::stringstream& help) const override {
        help << "multicasts a command to hosts in a system";
    }

    // no privs because it's a test command
    void addRequiredPrivileges(const std::string& dbname,
                               const BSONObj& cmdObj,
                               std::vector<Privilege>* out) override {}

    bool run(OperationContext* opCtx,
             const std::string& dbname,
             const BSONObj& cmdObj,
             BSONObjBuilder& result) override {
        IDLParserErrorContext ctx("ClusterMulticastArgs");
        auto args = ClusterMulticastArgs::parse(ctx, cmdObj);

        // Grab an arbitrary executor.
        auto executor = Grid::get(opCtx)->getExecutorPool()->getArbitraryExecutor();

        // Grab all hosts in the cluster.
        auto servers = getAllClusterHosts(opCtx);

        executor::AsyncMulticaster::Options options;
        if (args.getConcurrency()) {
            options.maxConcurrency = *args.getConcurrency();
        }

        auto results =
            executor::AsyncMulticaster(executor, options)
                .multicast(servers,
                           args.getDb().toString(),
                           args.getMulticast(),
                           opCtx,
                           (args.getTimeout() ? Milliseconds(*args.getTimeout())
                                              : executor::RemoteCommandRequest::kNoTimeout));

        bool success = true;

        {
            BSONObjBuilder bob(result.subobjStart("hosts"));

            for (const auto& r : results) {
                HostAndPort host;
                executor::RemoteCommandResponse response;
                std::tie(host, response) = r;

                if (!response.isOK() || !response.data["ok"].trueValue()) {
                    success = false;
                }

                {
                    BSONObjBuilder subbob(bob.subobjStart(host.toString()));

                    if (appendCommandStatus(subbob, response.status)) {
                        subbob.append("data", response.data);
                        subbob.append("metadata", response.metadata);
                        if (response.elapsedMillis) {
                            subbob.append("elapsedMillis", response.elapsedMillis->count());
                        }
                    }
                }
            }
        }

        return success;
    }
};

MONGO_INITIALIZER(RegisterMulticast)(InitializerContext* context) {
    if (Command::testCommandsEnabled) {
        new MulticastCmd();
    }
    return Status::OK();
}

}  // namespace
}  // namespace mongo
