clientobject: add null checks

[waspsaliva.git] / src / server.cpp

/*
Minetest
Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "server.h"
#include <iostream>
#include <queue>
#include <algorithm>
#include "network/connection.h"
#include "network/networkprotocol.h"
#include "network/serveropcodes.h"
#include "ban.h"
#include "environment.h"
#include "map.h"
#include "threading/mutex_auto_lock.h"
#include "constants.h"
#include "voxel.h"
#include "config.h"
#include "version.h"
#include "filesys.h"
#include "mapblock.h"
#include "server/serveractiveobject.h"
#include "settings.h"
#include "profiler.h"
#include "log.h"
#include "scripting_server.h"
#include "nodedef.h"
#include "itemdef.h"
#include "craftdef.h"
#include "emerge.h"
#include "mapgen/mapgen.h"
#include "mapgen/mg_biome.h"
#include "content_mapnode.h"
#include "content_nodemeta.h"
#include "content/mods.h"
#include "modchannels.h"
#include "serverlist.h"
#include "util/string.h"
#include "rollback.h"
#include "util/serialize.h"
#include "util/thread.h"
#include "defaultsettings.h"
#include "server/mods.h"
#include "util/base64.h"
#include "util/sha1.h"
#include "util/hex.h"
#include "database/database.h"
#include "chatmessage.h"
#include "chat_interface.h"
#include "remoteplayer.h"
#include "server/player_sao.h"
#include "server/serverinventorymgr.h"
#include "translation.h"

class ClientNotFoundException : public BaseException
{
public:
        ClientNotFoundException(const char *s):
                BaseException(s)
        {}
};

class ServerThread : public Thread
{
public:

        ServerThread(Server *server):
                Thread("Server"),
                m_server(server)
        {}

        void *run();

private:
        Server *m_server;
};

void *ServerThread::run()
{
        BEGIN_DEBUG_EXCEPTION_HANDLER

        /*
         * The real business of the server happens on the ServerThread.
         * How this works:
         * AsyncRunStep() runs an actual server step as soon as enough time has
         * passed (dedicated_server_loop keeps track of that).
         * Receive() blocks at least(!) 30ms waiting for a packet (so this loop
         * doesn't busy wait) and will process any remaining packets.
         */

        m_server->AsyncRunStep(true);

        while (!stopRequested()) {
                try {
                        m_server->AsyncRunStep();

                        m_server->Receive();

                } catch (con::PeerNotFoundException &e) {
                        infostream<<"Server: PeerNotFoundException"<<std::endl;
                } catch (ClientNotFoundException &e) {
                } catch (con::ConnectionBindFailed &e) {
                        m_server->setAsyncFatalError(e.what());
                } catch (LuaError &e) {
                        m_server->setAsyncFatalError(
                                        "ServerThread::run Lua: " + std::string(e.what()));
                }
        }

        END_DEBUG_EXCEPTION_HANDLER

        return nullptr;
}

v3f ServerSoundParams::getPos(ServerEnvironment *env, bool *pos_exists) const
{
        if(pos_exists) *pos_exists = false;
        switch(type){
        case SSP_LOCAL:
                return v3f(0,0,0);
        case SSP_POSITIONAL:
                if(pos_exists) *pos_exists = true;
                return pos;
        case SSP_OBJECT: {
                if(object == 0)
                        return v3f(0,0,0);
                ServerActiveObject *sao = env->getActiveObject(object);
                if(!sao)
                        return v3f(0,0,0);
                if(pos_exists) *pos_exists = true;
                return sao->getBasePosition(); }
        }
        return v3f(0,0,0);
}

void Server::ShutdownState::reset()
{
        m_timer = 0.0f;
        message.clear();
        should_reconnect = false;
        is_requested = false;
}

void Server::ShutdownState::trigger(float delay, const std::string &msg, bool reconnect)
{
        m_timer = delay;
        message = msg;
        should_reconnect = reconnect;
}

void Server::ShutdownState::tick(float dtime, Server *server)
{
        if (m_timer <= 0.0f)
                return;

        // Timed shutdown
        static const float shutdown_msg_times[] =
        {
                1, 2, 3, 4, 5, 10, 20, 40, 60, 120, 180, 300, 600, 1200, 1800, 3600
        };

        // Automated messages
        if (m_timer < shutdown_msg_times[ARRLEN(shutdown_msg_times) - 1]) {
                for (float t : shutdown_msg_times) {
                        // If shutdown timer matches an automessage, shot it
                        if (m_timer > t && m_timer - dtime < t) {
                                std::wstring periodicMsg = getShutdownTimerMessage();

                                infostream << wide_to_utf8(periodicMsg).c_str() << std::endl;
                                server->SendChatMessage(PEER_ID_INEXISTENT, periodicMsg);
                                break;
                        }
                }
        }

        m_timer -= dtime;
        if (m_timer < 0.0f) {
                m_timer = 0.0f;
                is_requested = true;
        }
}

std::wstring Server::ShutdownState::getShutdownTimerMessage() const
{
        std::wstringstream ws;
        ws << L"*** Server shutting down in "
                << duration_to_string(myround(m_timer)).c_str() << ".";
        return ws.str();
}

/*
        Server
*/

Server::Server(
                const std::string &path_world,
                const SubgameSpec &gamespec,
                bool simple_singleplayer_mode,
                Address bind_addr,
                bool dedicated,
                ChatInterface *iface,
                std::string *on_shutdown_errmsg
        ):
        m_bind_addr(bind_addr),
        m_path_world(path_world),
        m_gamespec(gamespec),
        m_simple_singleplayer_mode(simple_singleplayer_mode),
        m_dedicated(dedicated),
        m_async_fatal_error(""),
        m_con(std::make_shared<con::Connection>(PROTOCOL_ID,
                        512,
                        CONNECTION_TIMEOUT,
                        m_bind_addr.isIPv6(),
                        this)),
        m_itemdef(createItemDefManager()),
        m_nodedef(createNodeDefManager()),
        m_craftdef(createCraftDefManager()),
        m_thread(new ServerThread(this)),
        m_clients(m_con),
        m_admin_chat(iface),
        m_on_shutdown_errmsg(on_shutdown_errmsg),
        m_modchannel_mgr(new ModChannelMgr())
{
        if (m_path_world.empty())
                throw ServerError("Supplied empty world path");

        if (!gamespec.isValid())
                throw ServerError("Supplied invalid gamespec");

#if USE_PROMETHEUS
        m_metrics_backend = std::unique_ptr<MetricsBackend>(createPrometheusMetricsBackend());
#else
        m_metrics_backend = std::unique_ptr<MetricsBackend>(new MetricsBackend());
#endif

        m_uptime_counter = m_metrics_backend->addCounter("minetest_core_server_uptime", "Server uptime (in seconds)");
        m_player_gauge = m_metrics_backend->addGauge("minetest_core_player_number", "Number of connected players");

        m_timeofday_gauge = m_metrics_backend->addGauge(
                        "minetest_core_timeofday",
                        "Time of day value");

        m_lag_gauge = m_metrics_backend->addGauge(
                        "minetest_core_latency",
                        "Latency value (in seconds)");

        m_aom_buffer_counter = m_metrics_backend->addCounter(
                        "minetest_core_aom_generated_count",
                        "Number of active object messages generated");

        m_packet_recv_counter = m_metrics_backend->addCounter(
                        "minetest_core_server_packet_recv",
                        "Processable packets received");

        m_packet_recv_processed_counter = m_metrics_backend->addCounter(
                        "minetest_core_server_packet_recv_processed",
                        "Valid received packets processed");

        m_lag_gauge->set(g_settings->getFloat("dedicated_server_step"));
}

Server::~Server()
{

        // Send shutdown message
        SendChatMessage(PEER_ID_INEXISTENT, ChatMessage(CHATMESSAGE_TYPE_ANNOUNCE,
                        L"*** Server shutting down"));

        if (m_env) {
                MutexAutoLock envlock(m_env_mutex);

                infostream << "Server: Saving players" << std::endl;
                m_env->saveLoadedPlayers();

                infostream << "Server: Kicking players" << std::endl;
                std::string kick_msg;
                bool reconnect = false;
                if (isShutdownRequested()) {
                        reconnect = m_shutdown_state.should_reconnect;
                        kick_msg = m_shutdown_state.message;
                }
                if (kick_msg.empty()) {
                        kick_msg = g_settings->get("kick_msg_shutdown");
                }
                m_env->saveLoadedPlayers(true);
                m_env->kickAllPlayers(SERVER_ACCESSDENIED_SHUTDOWN,
                        kick_msg, reconnect);
        }

        actionstream << "Server: Shutting down" << std::endl;

        // Do this before stopping the server in case mapgen callbacks need to access
        // server-controlled resources (like ModStorages). Also do them before
        // shutdown callbacks since they may modify state that is finalized in a
        // callback.
        if (m_emerge)
                m_emerge->stopThreads();

        if (m_env) {
                MutexAutoLock envlock(m_env_mutex);

                // Execute script shutdown hooks
                infostream << "Executing shutdown hooks" << std::endl;
                try {
                        m_script->on_shutdown();
                } catch (ModError &e) {
                        errorstream << "ModError: " << e.what() << std::endl;
                        if (m_on_shutdown_errmsg) {
                                if (m_on_shutdown_errmsg->empty()) {
                                        *m_on_shutdown_errmsg = std::string("ModError: ") + e.what();
                                } else {
                                        *m_on_shutdown_errmsg += std::string("\nModError: ") + e.what();
                                }
                        }
                }

                infostream << "Server: Saving environment metadata" << std::endl;
                m_env->saveMeta();
        }

        // Stop threads
        if (m_thread) {
                stop();
                delete m_thread;
        }

        // Delete things in the reverse order of creation
        delete m_emerge;
        delete m_env;
        delete m_rollback;
        delete m_banmanager;
        delete m_itemdef;
        delete m_nodedef;
        delete m_craftdef;

        // Deinitialize scripting
        infostream << "Server: Deinitializing scripting" << std::endl;
        delete m_script;

        while (!m_unsent_map_edit_queue.empty()) {
                delete m_unsent_map_edit_queue.front();
                m_unsent_map_edit_queue.pop();
        }
}

void Server::init()
{
        infostream << "Server created for gameid \"" << m_gamespec.id << "\"";
        if (m_simple_singleplayer_mode)
                infostream << " in simple singleplayer mode" << std::endl;
        else
                infostream << std::endl;
        infostream << "- world:  " << m_path_world << std::endl;
        infostream << "- game:   " << m_gamespec.path << std::endl;

        // Create world if it doesn't exist
        try {
                loadGameConfAndInitWorld(m_path_world,
                                fs::GetFilenameFromPath(m_path_world.c_str()),
                                m_gamespec, false);
        } catch (const BaseException &e) {
                throw ServerError(std::string("Failed to initialize world: ") + e.what());
        }

        // Create emerge manager
        m_emerge = new EmergeManager(this);

        // Create ban manager
        std::string ban_path = m_path_world + DIR_DELIM "ipban.txt";
        m_banmanager = new BanManager(ban_path);

        m_modmgr = std::unique_ptr<ServerModManager>(new ServerModManager(m_path_world));
        std::vector<ModSpec> unsatisfied_mods = m_modmgr->getUnsatisfiedMods();
        // complain about mods with unsatisfied dependencies
        if (!m_modmgr->isConsistent()) {
                m_modmgr->printUnsatisfiedModsError();
        }

        //lock environment
        MutexAutoLock envlock(m_env_mutex);

        // Create the Map (loads map_meta.txt, overriding configured mapgen params)
        ServerMap *servermap = new ServerMap(m_path_world, this, m_emerge, m_metrics_backend.get());

        // Initialize scripting
        infostream << "Server: Initializing Lua" << std::endl;

        m_script = new ServerScripting(this);

        // Must be created before mod loading because we have some inventory creation
        m_inventory_mgr = std::unique_ptr<ServerInventoryManager>(new ServerInventoryManager());

        m_script->loadMod(getBuiltinLuaPath() + DIR_DELIM "init.lua", BUILTIN_MOD_NAME);

        m_modmgr->loadMods(m_script);

        // Read Textures and calculate sha1 sums
        fillMediaCache();

        // Apply item aliases in the node definition manager
        m_nodedef->updateAliases(m_itemdef);

        // Apply texture overrides from texturepack/override.txt
        std::vector<std::string> paths;
        fs::GetRecursiveDirs(paths, g_settings->get("texture_path"));
        fs::GetRecursiveDirs(paths, m_gamespec.path + DIR_DELIM + "textures");
        for (const std::string &path : paths) {
                TextureOverrideSource override_source(path + DIR_DELIM + "override.txt");
                m_nodedef->applyTextureOverrides(override_source.getNodeTileOverrides());
                m_itemdef->applyTextureOverrides(override_source.getItemTextureOverrides());
        }

        m_nodedef->setNodeRegistrationStatus(true);

        // Perform pending node name resolutions
        m_nodedef->runNodeResolveCallbacks();

        // unmap node names in cross-references
        m_nodedef->resolveCrossrefs();

        // init the recipe hashes to speed up crafting
        m_craftdef->initHashes(this);

        // Initialize Environment
        m_env = new ServerEnvironment(servermap, m_script, this, m_path_world);

        m_inventory_mgr->setEnv(m_env);
        m_clients.setEnv(m_env);

        if (!servermap->settings_mgr.makeMapgenParams())
                FATAL_ERROR("Couldn't create any mapgen type");

        // Initialize mapgens
        m_emerge->initMapgens(servermap->getMapgenParams());

        if (g_settings->getBool("enable_rollback_recording")) {
                // Create rollback manager
                m_rollback = new RollbackManager(m_path_world, this);
        }

        // Give environment reference to scripting api
        m_script->initializeEnvironment(m_env);

        // Register us to receive map edit events
        servermap->addEventReceiver(this);

        m_env->loadMeta();

        // Those settings can be overwritten in world.mt, they are
        // intended to be cached after environment loading.
        m_liquid_transform_every = g_settings->getFloat("liquid_update");
        m_max_chatmessage_length = g_settings->getU16("chat_message_max_size");
        m_csm_restriction_flags = g_settings->getU64("csm_restriction_flags");
        m_csm_restriction_noderange = g_settings->getU32("csm_restriction_noderange");
}

void Server::start()
{
        init();

        infostream << "Starting server on " << m_bind_addr.serializeString()
                        << "..." << std::endl;

        // Stop thread if already running
        m_thread->stop();

        // Initialize connection
        m_con->SetTimeoutMs(30);
        m_con->Serve(m_bind_addr);

        // Start thread
        m_thread->start();

        // ASCII art for the win!
        std::cerr
                << "        .__               __                   __   " << std::endl
                << "  _____ |__| ____   _____/  |_  ____   _______/  |_ " << std::endl
                << " /     \\|  |/    \\_/ __ \\   __\\/ __ \\ /  ___/\\   __\\" << std::endl
                << "|  Y Y  \\  |   |  \\  ___/|  | \\  ___/ \\___ \\  |  |  " << std::endl
                << "|__|_|  /__|___|  /\\___  >__|  \\___  >____  > |__|  " << std::endl
                << "      \\/        \\/     \\/          \\/     \\/        " << std::endl;
        actionstream << "World at [" << m_path_world << "]" << std::endl;
        actionstream << "Server for gameid=\"" << m_gamespec.id
                        << "\" listening on " << m_bind_addr.serializeString() << ":"
                        << m_bind_addr.getPort() << "." << std::endl;
}

void Server::stop()
{
        infostream<<"Server: Stopping and waiting threads"<<std::endl;

        // Stop threads (set run=false first so both start stopping)
        m_thread->stop();
        //m_emergethread.setRun(false);
        m_thread->wait();
        //m_emergethread.stop();

        infostream<<"Server: Threads stopped"<<std::endl;
}

void Server::step(float dtime)
{
        // Limit a bit
        if (dtime > 2.0)
                dtime = 2.0;
        {
                MutexAutoLock lock(m_step_dtime_mutex);
                m_step_dtime += dtime;
        }
        // Throw if fatal error occurred in thread
        std::string async_err = m_async_fatal_error.get();
        if (!async_err.empty()) {
                if (!m_simple_singleplayer_mode) {
                        m_env->kickAllPlayers(SERVER_ACCESSDENIED_CRASH,
                                g_settings->get("kick_msg_crash"),
                                g_settings->getBool("ask_reconnect_on_crash"));
                }
                throw ServerError("AsyncErr: " + async_err);
        }
}

void Server::AsyncRunStep(bool initial_step)
{

        float dtime;
        {
                MutexAutoLock lock1(m_step_dtime_mutex);
                dtime = m_step_dtime;
        }

        {
                // Send blocks to clients
                SendBlocks(dtime);
        }

        if((dtime < 0.001) && !initial_step)
                return;

        ScopeProfiler sp(g_profiler, "Server::AsyncRunStep()", SPT_AVG);

        {
                MutexAutoLock lock1(m_step_dtime_mutex);
                m_step_dtime -= dtime;
        }

        /*
                Update uptime
        */
        m_uptime_counter->increment(dtime);

        handlePeerChanges();

        /*
                Update time of day and overall game time
        */
        m_env->setTimeOfDaySpeed(g_settings->getFloat("time_speed"));

        /*
                Send to clients at constant intervals
        */

        m_time_of_day_send_timer -= dtime;
        if (m_time_of_day_send_timer < 0.0) {
                m_time_of_day_send_timer = g_settings->getFloat("time_send_interval");
                u16 time = m_env->getTimeOfDay();
                float time_speed = g_settings->getFloat("time_speed");
                SendTimeOfDay(PEER_ID_INEXISTENT, time, time_speed);

                m_timeofday_gauge->set(time);
        }

        {
                MutexAutoLock lock(m_env_mutex);
                // Figure out and report maximum lag to environment
                float max_lag = m_env->getMaxLagEstimate();
                max_lag *= 0.9998; // Decrease slowly (about half per 5 minutes)
                if(dtime > max_lag){
                        if(dtime > 0.1 && dtime > max_lag * 2.0)
                                infostream<<"Server: Maximum lag peaked to "<<dtime
                                                <<" s"<<std::endl;
                        max_lag = dtime;
                }
                m_env->reportMaxLagEstimate(max_lag);
                // Step environment
                m_env->step(dtime);
        }

        static const float map_timer_and_unload_dtime = 2.92;
        if(m_map_timer_and_unload_interval.step(dtime, map_timer_and_unload_dtime))
        {
                MutexAutoLock lock(m_env_mutex);
                // Run Map's timers and unload unused data
                ScopeProfiler sp(g_profiler, "Server: map timer and unload");
                m_env->getMap().timerUpdate(map_timer_and_unload_dtime,
                        g_settings->getFloat("server_unload_unused_data_timeout"),
                        U32_MAX);
        }

        /*
                Listen to the admin chat, if available
        */
        if (m_admin_chat) {
                if (!m_admin_chat->command_queue.empty()) {
                        MutexAutoLock lock(m_env_mutex);
                        while (!m_admin_chat->command_queue.empty()) {
                                ChatEvent *evt = m_admin_chat->command_queue.pop_frontNoEx();
                                handleChatInterfaceEvent(evt);
                                delete evt;
                        }
                }
                m_admin_chat->outgoing_queue.push_back(
                        new ChatEventTimeInfo(m_env->getGameTime(), m_env->getTimeOfDay()));
        }

        /*
                Do background stuff
        */

        /* Transform liquids */
        m_liquid_transform_timer += dtime;
        if(m_liquid_transform_timer >= m_liquid_transform_every)
        {
                m_liquid_transform_timer -= m_liquid_transform_every;

                MutexAutoLock lock(m_env_mutex);

                ScopeProfiler sp(g_profiler, "Server: liquid transform");

                std::map<v3s16, MapBlock*> modified_blocks;
                m_env->getMap().transformLiquids(modified_blocks, m_env);

                /*
                        Set the modified blocks unsent for all the clients
                */
                if (!modified_blocks.empty()) {
                        SetBlocksNotSent(modified_blocks);
                }
        }
        m_clients.step(dtime);

        // increase/decrease lag gauge gradually
        if (m_lag_gauge->get() > dtime) {
                m_lag_gauge->decrement(dtime/100);
        } else {
                m_lag_gauge->increment(dtime/100);
        }
#if USE_CURL
        // send masterserver announce
        {
                float &counter = m_masterserver_timer;
                if (!isSingleplayer() && (!counter || counter >= 300.0) &&
                                g_settings->getBool("server_announce")) {
                        ServerList::sendAnnounce(counter ? ServerList::AA_UPDATE :
                                                ServerList::AA_START,
                                        m_bind_addr.getPort(),
                                        m_clients.getPlayerNames(),
                                        m_uptime_counter->get(),
                                        m_env->getGameTime(),
                                        m_lag_gauge->get(),
                                        m_gamespec.id,
                                        Mapgen::getMapgenName(m_emerge->mgparams->mgtype),
                                        m_modmgr->getMods(),
                                        m_dedicated);
                        counter = 0.01;
                }
                counter += dtime;
        }
#endif

        /*
                Check added and deleted active objects
        */
        {
                //infostream<<"Server: Checking added and deleted active objects"<<std::endl;
                MutexAutoLock envlock(m_env_mutex);

                m_clients.lock();
                const RemoteClientMap &clients = m_clients.getClientList();
                ScopeProfiler sp(g_profiler, "Server: update objects within range");

                m_player_gauge->set(clients.size());
                for (const auto &client_it : clients) {
                        RemoteClient *client = client_it.second;

                        if (client->getState() < CS_DefinitionsSent)
                                continue;

                        // This can happen if the client times out somehow
                        if (!m_env->getPlayer(client->peer_id))
                                continue;

                        PlayerSAO *playersao = getPlayerSAO(client->peer_id);
                        if (!playersao)
                                continue;

                        SendActiveObjectRemoveAdd(client, playersao);
                }
                m_clients.unlock();

                // Save mod storages if modified
                m_mod_storage_save_timer -= dtime;
                if (m_mod_storage_save_timer <= 0.0f) {
                        m_mod_storage_save_timer = g_settings->getFloat("server_map_save_interval");
                        int n = 0;
                        for (std::unordered_map<std::string, ModMetadata *>::const_iterator
                                it = m_mod_storages.begin(); it != m_mod_storages.end(); ++it) {
                                if (it->second->isModified()) {
                                        it->second->save(getModStoragePath());
                                        n++;
                                }
                        }
                        if (n > 0)
                                infostream << "Saved " << n << " modified mod storages." << std::endl;
                }
        }

        /*
                Send object messages
        */
        {
                MutexAutoLock envlock(m_env_mutex);
                ScopeProfiler sp(g_profiler, "Server: send SAO messages");

                // Key = object id
                // Value = data sent by object
                std::unordered_map<u16, std::vector<ActiveObjectMessage>*> buffered_messages;

                // Get active object messages from environment
                ActiveObjectMessage aom(0);
                u32 aom_count = 0;
                for(;;) {
                        if (!m_env->getActiveObjectMessage(&aom))
                                break;

                        std::vector<ActiveObjectMessage>* message_list = nullptr;
                        auto n = buffered_messages.find(aom.id);
                        if (n == buffered_messages.end()) {
                                message_list = new std::vector<ActiveObjectMessage>;
                                buffered_messages[aom.id] = message_list;
                        } else {
                                message_list = n->second;
                        }
                        message_list->push_back(std::move(aom));
                        aom_count++;
                }

                m_aom_buffer_counter->increment(aom_count);

                m_clients.lock();
                const RemoteClientMap &clients = m_clients.getClientList();
                // Route data to every client
                std::string reliable_data, unreliable_data;
                for (const auto &client_it : clients) {
                        reliable_data.clear();
                        unreliable_data.clear();
                        RemoteClient *client = client_it.second;
                        PlayerSAO *player = getPlayerSAO(client->peer_id);
                        // Go through all objects in message buffer
                        for (const auto &buffered_message : buffered_messages) {
                                // If object does not exist or is not known by client, skip it
                                u16 id = buffered_message.first;
                                ServerActiveObject *sao = m_env->getActiveObject(id);
                                if (!sao || client->m_known_objects.find(id) == client->m_known_objects.end())
                                        continue;

                                // Get message list of object
                                std::vector<ActiveObjectMessage>* list = buffered_message.second;
                                // Go through every message
                                for (const ActiveObjectMessage &aom : *list) {
                                        // Send position updates to players who do not see the attachment
                                        if (aom.datastring[0] == AO_CMD_UPDATE_POSITION) {
                                                if (sao->getId() == player->getId())
                                                        continue;

                                                // Do not send position updates for attached players
                                                // as long the parent is known to the client
                                                ServerActiveObject *parent = sao->getParent();
                                                if (parent && client->m_known_objects.find(parent->getId()) !=
                                                                client->m_known_objects.end())
                                                        continue;
                                        }

                                        // Add full new data to appropriate buffer
                                        std::string &buffer = aom.reliable ? reliable_data : unreliable_data;
                                        char idbuf[2];
                                        writeU16((u8*) idbuf, aom.id);
                                        // u16 id
                                        // std::string data
                                        buffer.append(idbuf, sizeof(idbuf));
                                        buffer.append(serializeString16(aom.datastring));
                                }
                        }
                        /*
                                reliable_data and unreliable_data are now ready.
                                Send them.
                        */
                        if (!reliable_data.empty()) {
                                SendActiveObjectMessages(client->peer_id, reliable_data);
                        }

                        if (!unreliable_data.empty()) {
                                SendActiveObjectMessages(client->peer_id, unreliable_data, false);
                        }
                }
                m_clients.unlock();

                // Clear buffered_messages
                for (auto &buffered_message : buffered_messages) {
                        delete buffered_message.second;
                }
        }

        /*
                Send queued-for-sending map edit events.
        */
        {
                // We will be accessing the environment
                MutexAutoLock lock(m_env_mutex);

                // Don't send too many at a time
                //u32 count = 0;

                // Single change sending is disabled if queue size is not small
                bool disable_single_change_sending = false;
                if(m_unsent_map_edit_queue.size() >= 4)
                        disable_single_change_sending = true;

                int event_count = m_unsent_map_edit_queue.size();

                // We'll log the amount of each
                Profiler prof;

                std::list<v3s16> node_meta_updates;

                while (!m_unsent_map_edit_queue.empty()) {
                        MapEditEvent* event = m_unsent_map_edit_queue.front();
                        m_unsent_map_edit_queue.pop();

                        // Players far away from the change are stored here.
                        // Instead of sending the changes, MapBlocks are set not sent
                        // for them.
                        std::unordered_set<u16> far_players;

                        switch (event->type) {
                        case MEET_ADDNODE:
                        case MEET_SWAPNODE:
                                prof.add("MEET_ADDNODE", 1);
                                sendAddNode(event->p, event->n, &far_players,
                                                disable_single_change_sending ? 5 : 30,
                                                event->type == MEET_ADDNODE);
                                break;
                        case MEET_REMOVENODE:
                                prof.add("MEET_REMOVENODE", 1);
                                sendRemoveNode(event->p, &far_players,
                                                disable_single_change_sending ? 5 : 30);
                                break;
                        case MEET_BLOCK_NODE_METADATA_CHANGED: {
                                prof.add("MEET_BLOCK_NODE_METADATA_CHANGED", 1);
                                if (!event->is_private_change) {
                                        // Don't send the change yet. Collect them to eliminate dupes.
                                        node_meta_updates.remove(event->p);
                                        node_meta_updates.push_back(event->p);
                                }

                                if (MapBlock *block = m_env->getMap().getBlockNoCreateNoEx(
                                                getNodeBlockPos(event->p))) {
                                        block->raiseModified(MOD_STATE_WRITE_NEEDED,
                                                MOD_REASON_REPORT_META_CHANGE);
                                }
                                break;
                        }
                        case MEET_OTHER:
                                prof.add("MEET_OTHER", 1);
                                for (const v3s16 &modified_block : event->modified_blocks) {
                                        m_clients.markBlockposAsNotSent(modified_block);
                                }
                                break;
                        default:
                                prof.add("unknown", 1);
                                warningstream << "Server: Unknown MapEditEvent "
                                                << ((u32)event->type) << std::endl;
                                break;
                        }

                        /*
                                Set blocks not sent to far players
                        */
                        if (!far_players.empty()) {
                                // Convert list format to that wanted by SetBlocksNotSent
                                std::map<v3s16, MapBlock*> modified_blocks2;
                                for (const v3s16 &modified_block : event->modified_blocks) {
                                        modified_blocks2[modified_block] =
                                                        m_env->getMap().getBlockNoCreateNoEx(modified_block);
                                }

                                // Set blocks not sent
                                for (const u16 far_player : far_players) {
                                        if (RemoteClient *client = getClient(far_player))
                                                client->SetBlocksNotSent(modified_blocks2);
                                }
                        }

                        delete event;
                }

                if (event_count >= 5) {
                        infostream << "Server: MapEditEvents:" << std::endl;
                        prof.print(infostream);
                } else if (event_count != 0) {
                        verbosestream << "Server: MapEditEvents:" << std::endl;
                        prof.print(verbosestream);
                }

                // Send all metadata updates
                if (node_meta_updates.size())
                        sendMetadataChanged(node_meta_updates);
        }

        /*
                Trigger emergethread (it somehow gets to a non-triggered but
                bysy state sometimes)
        */
        {
                float &counter = m_emergethread_trigger_timer;
                counter += dtime;
                if (counter >= 2.0) {
                        counter = 0.0;

                        m_emerge->startThreads();
                }
        }

        // Save map, players and auth stuff
        {
                float &counter = m_savemap_timer;
                counter += dtime;
                static thread_local const float save_interval =
                        g_settings->getFloat("server_map_save_interval");
                if (counter >= save_interval) {
                        counter = 0.0;
                        MutexAutoLock lock(m_env_mutex);

                        ScopeProfiler sp(g_profiler, "Server: map saving (sum)");

                        // Save ban file
                        if (m_banmanager->isModified()) {
                                m_banmanager->save();
                        }

                        // Save changed parts of map
                        m_env->getMap().save(MOD_STATE_WRITE_NEEDED);

                        // Save players
                        m_env->saveLoadedPlayers();

                        // Save environment metadata
                        m_env->saveMeta();
                }
        }

        m_shutdown_state.tick(dtime, this);
}

void Server::Receive()
{
        NetworkPacket pkt;
        session_t peer_id;
        bool first = true;
        for (;;) {
                pkt.clear();
                peer_id = 0;
                try {
                        /*
                                In the first iteration *wait* for a packet, afterwards process
                                all packets that are immediately available (no waiting).
                        */
                        if (first) {
                                m_con->Receive(&pkt);
                                first = false;
                        } else {
                                if (!m_con->TryReceive(&pkt))
                                        return;
                        }

                        peer_id = pkt.getPeerId();
                        m_packet_recv_counter->increment();
                        ProcessData(&pkt);
                        m_packet_recv_processed_counter->increment();
                } catch (const con::InvalidIncomingDataException &e) {
                        infostream << "Server::Receive(): InvalidIncomingDataException: what()="
                                        << e.what() << std::endl;
                } catch (const SerializationError &e) {
                        infostream << "Server::Receive(): SerializationError: what()="
                                        << e.what() << std::endl;
                } catch (const ClientStateError &e) {
                        errorstream << "ProcessData: peer=" << peer_id << " what()="
                                         << e.what() << std::endl;
                        DenyAccess_Legacy(peer_id, L"Your client sent something server didn't expect."
                                        L"Try reconnecting or updating your client");
                } catch (const con::PeerNotFoundException &e) {
                        // Do nothing
                } catch (const con::NoIncomingDataException &e) {
                        return;
                }
        }
}

PlayerSAO* Server::StageTwoClientInit(session_t peer_id)
{
        std::string playername;
        PlayerSAO *playersao = NULL;
        m_clients.lock();
        try {
                RemoteClient* client = m_clients.lockedGetClientNoEx(peer_id, CS_InitDone);
                if (client) {
                        playername = client->getName();
                        playersao = emergePlayer(playername.c_str(), peer_id, client->net_proto_version);
                }
        } catch (std::exception &e) {
                m_clients.unlock();
                throw;
        }
        m_clients.unlock();

        RemotePlayer *player = m_env->getPlayer(playername.c_str());

        // If failed, cancel
        if (!playersao || !player) {
                if (player && player->getPeerId() != PEER_ID_INEXISTENT) {
                        actionstream << "Server: Failed to emerge player \"" << playername
                                        << "\" (player allocated to an another client)" << std::endl;
                        DenyAccess_Legacy(peer_id, L"Another client is connected with this "
                                        L"name. If your client closed unexpectedly, try again in "
                                        L"a minute.");
                } else {
                        errorstream << "Server: " << playername << ": Failed to emerge player"
                                        << std::endl;
                        DenyAccess_Legacy(peer_id, L"Could not allocate player.");
                }
                return NULL;
        }

        /*
                Send complete position information
        */
        SendMovePlayer(peer_id);

        // Send privileges
        SendPlayerPrivileges(peer_id);

        // Send inventory formspec
        SendPlayerInventoryFormspec(peer_id);

        // Send inventory
        SendInventory(playersao, false);

        // Send HP or death screen
        if (playersao->isDead())
                SendDeathscreen(peer_id, false, v3f(0,0,0));
        else
                SendPlayerHPOrDie(playersao,
                                PlayerHPChangeReason(PlayerHPChangeReason::SET_HP));

        // Send Breath
        SendPlayerBreath(playersao);

        /*
                Print out action
        */
        {
                Address addr = getPeerAddress(player->getPeerId());
                std::string ip_str = addr.serializeString();
                const std::vector<std::string> &names = m_clients.getPlayerNames();

                actionstream << player->getName() << " [" << ip_str << "] joins game. List of players: ";

                for (const std::string &name : names) {
                        actionstream << name << " ";
                }

                actionstream << player->getName() <<std::endl;
        }
        return playersao;
}

inline void Server::handleCommand(NetworkPacket *pkt)
{
        const ToServerCommandHandler &opHandle = toServerCommandTable[pkt->getCommand()];
        (this->*opHandle.handler)(pkt);
}

void Server::ProcessData(NetworkPacket *pkt)
{
        // Environment is locked first.
        MutexAutoLock envlock(m_env_mutex);

        ScopeProfiler sp(g_profiler, "Server: Process network packet (sum)");
        u32 peer_id = pkt->getPeerId();

        try {
                Address address = getPeerAddress(peer_id);
                std::string addr_s = address.serializeString();

                if(m_banmanager->isIpBanned(addr_s)) {
                        std::string ban_name = m_banmanager->getBanName(addr_s);
                        infostream << "Server: A banned client tried to connect from "
                                        << addr_s << "; banned name was "
                                        << ban_name << std::endl;
                        // This actually doesn't seem to transfer to the client
                        DenyAccess_Legacy(peer_id, L"Your ip is banned. Banned name was "
                                        + utf8_to_wide(ban_name));
                        return;
                }
        }
        catch(con::PeerNotFoundException &e) {
                /*
                 * no peer for this packet found
                 * most common reason is peer timeout, e.g. peer didn't
                 * respond for some time, your server was overloaded or
                 * things like that.
                 */
                infostream << "Server::ProcessData(): Canceling: peer "
                                << peer_id << " not found" << std::endl;
                return;
        }

        try {
                ToServerCommand command = (ToServerCommand) pkt->getCommand();

                // Command must be handled into ToServerCommandHandler
                if (command >= TOSERVER_NUM_MSG_TYPES) {
                        infostream << "Server: Ignoring unknown command "
                                         << command << std::endl;
                        return;
                }

                if (toServerCommandTable[command].state == TOSERVER_STATE_NOT_CONNECTED) {
                        handleCommand(pkt);
                        return;
                }

                u8 peer_ser_ver = getClient(peer_id, CS_InitDone)->serialization_version;

                if(peer_ser_ver == SER_FMT_VER_INVALID) {
                        errorstream << "Server::ProcessData(): Cancelling: Peer"
                                        " serialization format invalid or not initialized."
                                        " Skipping incoming command=" << command << std::endl;
                        return;
                }

                /* Handle commands related to client startup */
                if (toServerCommandTable[command].state == TOSERVER_STATE_STARTUP) {
                        handleCommand(pkt);
                        return;
                }

                if (m_clients.getClientState(peer_id) < CS_Active) {
                        if (command == TOSERVER_PLAYERPOS) return;

                        errorstream << "Got packet command: " << command << " for peer id "
                                        << peer_id << " but client isn't active yet. Dropping packet "
                                        << std::endl;
                        return;
                }

                handleCommand(pkt);
        } catch (SendFailedException &e) {
                errorstream << "Server::ProcessData(): SendFailedException: "
                                << "what=" << e.what()
                                << std::endl;
        } catch (PacketError &e) {
                actionstream << "Server::ProcessData(): PacketError: "
                                << "what=" << e.what()
                                << std::endl;
        }
}

void Server::setTimeOfDay(u32 time)
{
        m_env->setTimeOfDay(time);
        m_time_of_day_send_timer = 0;
}

void Server::onMapEditEvent(const MapEditEvent &event)
{
        if (m_ignore_map_edit_events_area.contains(event.getArea()))
                return;

        m_unsent_map_edit_queue.push(new MapEditEvent(event));
}

void Server::SetBlocksNotSent(std::map<v3s16, MapBlock *>& block)
{
        std::vector<session_t> clients = m_clients.getClientIDs();
        m_clients.lock();
        // Set the modified blocks unsent for all the clients
        for (const session_t client_id : clients) {
                        if (RemoteClient *client = m_clients.lockedGetClientNoEx(client_id))
                                client->SetBlocksNotSent(block);
        }
        m_clients.unlock();
}

void Server::peerAdded(con::Peer *peer)
{
        verbosestream<<"Server::peerAdded(): peer->id="
                        <<peer->id<<std::endl;

        m_peer_change_queue.push(con::PeerChange(con::PEER_ADDED, peer->id, false));
}

void Server::deletingPeer(con::Peer *peer, bool timeout)
{
        verbosestream<<"Server::deletingPeer(): peer->id="
                        <<peer->id<<", timeout="<<timeout<<std::endl;

        m_clients.event(peer->id, CSE_Disconnect);
        m_peer_change_queue.push(con::PeerChange(con::PEER_REMOVED, peer->id, timeout));
}

bool Server::getClientConInfo(session_t peer_id, con::rtt_stat_type type, float* retval)
{
        *retval = m_con->getPeerStat(peer_id,type);
        return *retval != -1;
}

bool Server::getClientInfo(
                session_t    peer_id,
                ClientState* state,
                u32*         uptime,
                u8*          ser_vers,
                u16*         prot_vers,
                u8*          major,
                u8*          minor,
                u8*          patch,
                std::string* vers_string,
                std::string* lang_code
        )
{
        *state = m_clients.getClientState(peer_id);
        m_clients.lock();
        RemoteClient* client = m_clients.lockedGetClientNoEx(peer_id, CS_Invalid);

        if (!client) {
                m_clients.unlock();
                return false;
        }

        *uptime = client->uptime();
        *ser_vers = client->serialization_version;
        *prot_vers = client->net_proto_version;

        *major = client->getMajor();
        *minor = client->getMinor();
        *patch = client->getPatch();
        *vers_string = client->getFull();
        *lang_code = client->getLangCode();

        m_clients.unlock();

        return true;
}

void Server::handlePeerChanges()
{
        while(!m_peer_change_queue.empty())
        {
                con::PeerChange c = m_peer_change_queue.front();
                m_peer_change_queue.pop();

                verbosestream<<"Server: Handling peer change: "
                                <<"id="<<c.peer_id<<", timeout="<<c.timeout
                                <<std::endl;

                switch(c.type)
                {
                case con::PEER_ADDED:
                        m_clients.CreateClient(c.peer_id);
                        break;

                case con::PEER_REMOVED:
                        DeleteClient(c.peer_id, c.timeout?CDR_TIMEOUT:CDR_LEAVE);
                        break;

                default:
                        FATAL_ERROR("Invalid peer change event received!");
                        break;
                }
        }
}

void Server::printToConsoleOnly(const std::string &text)
{
        if (m_admin_chat) {
                m_admin_chat->outgoing_queue.push_back(
                        new ChatEventChat("", utf8_to_wide(text)));
        } else {
                std::cout << text << std::endl;
        }
}

void Server::Send(NetworkPacket *pkt)
{
        Send(pkt->getPeerId(), pkt);
}

void Server::Send(session_t peer_id, NetworkPacket *pkt)
{
        m_clients.send(peer_id,
                clientCommandFactoryTable[pkt->getCommand()].channel,
                pkt,
                clientCommandFactoryTable[pkt->getCommand()].reliable);
}

void Server::SendMovement(session_t peer_id)
{
        std::ostringstream os(std::ios_base::binary);

        NetworkPacket pkt(TOCLIENT_MOVEMENT, 12 * sizeof(float), peer_id);

        pkt << g_settings->getFloat("movement_acceleration_default");
        pkt << g_settings->getFloat("movement_acceleration_air");
        pkt << g_settings->getFloat("movement_acceleration_fast");
        pkt << g_settings->getFloat("movement_speed_walk");
        pkt << g_settings->getFloat("movement_speed_crouch");
        pkt << g_settings->getFloat("movement_speed_fast");
        pkt << g_settings->getFloat("movement_speed_climb");
        pkt << g_settings->getFloat("movement_speed_jump");
        pkt << g_settings->getFloat("movement_liquid_fluidity");
        pkt << g_settings->getFloat("movement_liquid_fluidity_smooth");
        pkt << g_settings->getFloat("movement_liquid_sink");
        pkt << g_settings->getFloat("movement_gravity");

        Send(&pkt);
}

void Server::SendPlayerHPOrDie(PlayerSAO *playersao, const PlayerHPChangeReason &reason)
{
        if (playersao->isImmortal())
                return;

        session_t peer_id = playersao->getPeerID();
        bool is_alive = playersao->getHP() > 0;

        if (is_alive)
                SendPlayerHP(peer_id);
        else
                DiePlayer(peer_id, reason);
}

void Server::SendHP(session_t peer_id, u16 hp)
{
        NetworkPacket pkt(TOCLIENT_HP, 1, peer_id);
        pkt << hp;
        Send(&pkt);
}

void Server::SendBreath(session_t peer_id, u16 breath)
{
        NetworkPacket pkt(TOCLIENT_BREATH, 2, peer_id);
        pkt << (u16) breath;
        Send(&pkt);
}

void Server::SendAccessDenied(session_t peer_id, AccessDeniedCode reason,
                const std::string &custom_reason, bool reconnect)
{
        assert(reason < SERVER_ACCESSDENIED_MAX);

        NetworkPacket pkt(TOCLIENT_ACCESS_DENIED, 1, peer_id);
        pkt << (u8)reason;
        if (reason == SERVER_ACCESSDENIED_CUSTOM_STRING)
                pkt << custom_reason;
        else if (reason == SERVER_ACCESSDENIED_SHUTDOWN ||
                        reason == SERVER_ACCESSDENIED_CRASH)
                pkt << custom_reason << (u8)reconnect;
        Send(&pkt);
}

void Server::SendAccessDenied_Legacy(session_t peer_id,const std::wstring &reason)
{
        NetworkPacket pkt(TOCLIENT_ACCESS_DENIED_LEGACY, 0, peer_id);
        pkt << reason;
        Send(&pkt);
}

void Server::SendDeathscreen(session_t peer_id, bool set_camera_point_target,
                v3f camera_point_target)
{
        NetworkPacket pkt(TOCLIENT_DEATHSCREEN, 1 + sizeof(v3f), peer_id);
        pkt << set_camera_point_target << camera_point_target;
        Send(&pkt);
}

void Server::SendItemDef(session_t peer_id,
                IItemDefManager *itemdef, u16 protocol_version)
{
        NetworkPacket pkt(TOCLIENT_ITEMDEF, 0, peer_id);

        /*
                u16 command
                u32 length of the next item
                zlib-compressed serialized ItemDefManager
        */
        std::ostringstream tmp_os(std::ios::binary);
        itemdef->serialize(tmp_os, protocol_version);
        std::ostringstream tmp_os2(std::ios::binary);
        compressZlib(tmp_os.str(), tmp_os2);
        pkt.putLongString(tmp_os2.str());

        // Make data buffer
        verbosestream << "Server: Sending item definitions to id(" << peer_id
                        << "): size=" << pkt.getSize() << std::endl;

        Send(&pkt);
}

void Server::SendNodeDef(session_t peer_id,
        const NodeDefManager *nodedef, u16 protocol_version)
{
        NetworkPacket pkt(TOCLIENT_NODEDEF, 0, peer_id);

        /*
                u16 command
                u32 length of the next item
                zlib-compressed serialized NodeDefManager
        */
        std::ostringstream tmp_os(std::ios::binary);
        nodedef->serialize(tmp_os, protocol_version);
        std::ostringstream tmp_os2(std::ios::binary);
        compressZlib(tmp_os.str(), tmp_os2);

        pkt.putLongString(tmp_os2.str());

        // Make data buffer
        verbosestream << "Server: Sending node definitions to id(" << peer_id
                        << "): size=" << pkt.getSize() << std::endl;

        Send(&pkt);
}

/*
        Non-static send methods
*/

void Server::SendInventory(PlayerSAO *sao, bool incremental)
{
        RemotePlayer *player = sao->getPlayer();

        // Do not send new format to old clients
        incremental &= player->protocol_version >= 38;

        UpdateCrafting(player);

        /*
                Serialize it
        */

        NetworkPacket pkt(TOCLIENT_INVENTORY, 0, sao->getPeerID());

        std::ostringstream os(std::ios::binary);
        sao->getInventory()->serialize(os, incremental);
        sao->getInventory()->setModified(false);
        player->setModified(true);

        const std::string &s = os.str();
        pkt.putRawString(s.c_str(), s.size());
        Send(&pkt);
}

void Server::SendChatMessage(session_t peer_id, const ChatMessage &message)
{
        NetworkPacket pkt(TOCLIENT_CHAT_MESSAGE, 0, peer_id);
        u8 version = 1;
        u8 type = message.type;
        pkt << version << type << std::wstring(L"") << message.message << (u64)message.timestamp;

        if (peer_id != PEER_ID_INEXISTENT) {
                RemotePlayer *player = m_env->getPlayer(peer_id);
                if (!player)
                        return;

                Send(&pkt);
        } else {
                m_clients.sendToAll(&pkt);
        }
}

void Server::SendShowFormspecMessage(session_t peer_id, const std::string &formspec,
        const std::string &formname)
{
        NetworkPacket pkt(TOCLIENT_SHOW_FORMSPEC, 0, peer_id);
        if (formspec.empty()){
                //the client should close the formspec
                //but make sure there wasn't another one open in meantime
                const auto it = m_formspec_state_data.find(peer_id);
                if (it != m_formspec_state_data.end() && it->second == formname) {
                        m_formspec_state_data.erase(peer_id);
                }
                pkt.putLongString("");
        } else {
                m_formspec_state_data[peer_id] = formname;
                pkt.putLongString(formspec);
        }
        pkt << formname;

        Send(&pkt);
}

// Spawns a particle on peer with peer_id
void Server::SendSpawnParticle(session_t peer_id, u16 protocol_version,
        const ParticleParameters &p)
{
        static thread_local const float radius =
                        g_settings->getS16("max_block_send_distance") * MAP_BLOCKSIZE * BS;

        if (peer_id == PEER_ID_INEXISTENT) {
                std::vector<session_t> clients = m_clients.getClientIDs();
                const v3f pos = p.pos * BS;
                const float radius_sq = radius * radius;

                for (const session_t client_id : clients) {
                        RemotePlayer *player = m_env->getPlayer(client_id);
                        if (!player)
                                continue;

                        PlayerSAO *sao = player->getPlayerSAO();
                        if (!sao)
                                continue;

                        // Do not send to distant clients
                        if (sao->getBasePosition().getDistanceFromSQ(pos) > radius_sq)
                                continue;

                        SendSpawnParticle(client_id, player->protocol_version, p);
                }
                return;
        }
        assert(protocol_version != 0);

        NetworkPacket pkt(TOCLIENT_SPAWN_PARTICLE, 0, peer_id);

        {
                // NetworkPacket and iostreams are incompatible...
                std::ostringstream oss(std::ios_base::binary);
                p.serialize(oss, protocol_version);
                pkt.putRawString(oss.str());
        }

        Send(&pkt);
}

// Adds a ParticleSpawner on peer with peer_id
void Server::SendAddParticleSpawner(session_t peer_id, u16 protocol_version,
        const ParticleSpawnerParameters &p, u16 attached_id, u32 id)
{
        static thread_local const float radius =
                        g_settings->getS16("max_block_send_distance") * MAP_BLOCKSIZE * BS;

        if (peer_id == PEER_ID_INEXISTENT) {
                std::vector<session_t> clients = m_clients.getClientIDs();
                const v3f pos = (p.minpos + p.maxpos) / 2.0f * BS;
                const float radius_sq = radius * radius;
                /* Don't send short-lived spawners to distant players.
                 * This could be replaced with proper tracking at some point. */
                const bool distance_check = !attached_id && p.time <= 1.0f;

                for (const session_t client_id : clients) {
                        RemotePlayer *player = m_env->getPlayer(client_id);
                        if (!player)
                                continue;

                        if (distance_check) {
                                PlayerSAO *sao = player->getPlayerSAO();
                                if (!sao)
                                        continue;
                                if (sao->getBasePosition().getDistanceFromSQ(pos) > radius_sq)
                                        continue;
                        }

                        SendAddParticleSpawner(client_id, player->protocol_version,
                                p, attached_id, id);
                }
                return;
        }
        assert(protocol_version != 0);

        NetworkPacket pkt(TOCLIENT_ADD_PARTICLESPAWNER, 100, peer_id);

        pkt << p.amount << p.time << p.minpos << p.maxpos << p.minvel
                << p.maxvel << p.minacc << p.maxacc << p.minexptime << p.maxexptime
                << p.minsize << p.maxsize << p.collisiondetection;

        pkt.putLongString(p.texture);

        pkt << id << p.vertical << p.collision_removal << attached_id;
        {
                std::ostringstream os(std::ios_base::binary);
                p.animation.serialize(os, protocol_version);
                pkt.putRawString(os.str());
        }
        pkt << p.glow << p.object_collision;
        pkt << p.node.param0 << p.node.param2 << p.node_tile;

        Send(&pkt);
}

void Server::SendDeleteParticleSpawner(session_t peer_id, u32 id)
{
        NetworkPacket pkt(TOCLIENT_DELETE_PARTICLESPAWNER, 4, peer_id);

        pkt << id;

        if (peer_id != PEER_ID_INEXISTENT)
                Send(&pkt);
        else
                m_clients.sendToAll(&pkt);

}

void Server::SendHUDAdd(session_t peer_id, u32 id, HudElement *form)
{
        NetworkPacket pkt(TOCLIENT_HUDADD, 0 , peer_id);

        pkt << id << (u8) form->type << form->pos << form->name << form->scale
                        << form->text << form->number << form->item << form->dir
                        << form->align << form->offset << form->world_pos << form->size
                        << form->z_index << form->text2;

        Send(&pkt);
}

void Server::SendHUDRemove(session_t peer_id, u32 id)
{
        NetworkPacket pkt(TOCLIENT_HUDRM, 4, peer_id);
        pkt << id;
        Send(&pkt);
}

void Server::SendHUDChange(session_t peer_id, u32 id, HudElementStat stat, void *value)
{
        NetworkPacket pkt(TOCLIENT_HUDCHANGE, 0, peer_id);
        pkt << id << (u8) stat;

        switch (stat) {
                case HUD_STAT_POS:
                case HUD_STAT_SCALE:
                case HUD_STAT_ALIGN:
                case HUD_STAT_OFFSET:
                        pkt << *(v2f *) value;
                        break;
                case HUD_STAT_NAME:
                case HUD_STAT_TEXT:
                case HUD_STAT_TEXT2:
                        pkt << *(std::string *) value;
                        break;
                case HUD_STAT_WORLD_POS:
                        pkt << *(v3f *) value;
                        break;
                case HUD_STAT_SIZE:
                        pkt << *(v2s32 *) value;
                        break;
                case HUD_STAT_NUMBER:
                case HUD_STAT_ITEM:
                case HUD_STAT_DIR:
                default:
                        pkt << *(u32 *) value;
                        break;
        }

        Send(&pkt);
}

void Server::SendHUDSetFlags(session_t peer_id, u32 flags, u32 mask)
{
        NetworkPacket pkt(TOCLIENT_HUD_SET_FLAGS, 4 + 4, peer_id);

        flags &= ~(HUD_FLAG_HEALTHBAR_VISIBLE | HUD_FLAG_BREATHBAR_VISIBLE);

        pkt << flags << mask;

        Send(&pkt);
}

void Server::SendHUDSetParam(session_t peer_id, u16 param, const std::string &value)
{
        NetworkPacket pkt(TOCLIENT_HUD_SET_PARAM, 0, peer_id);
        pkt << param << value;
        Send(&pkt);
}

void Server::SendSetSky(session_t peer_id, const SkyboxParams &params)
{
        NetworkPacket pkt(TOCLIENT_SET_SKY, 0, peer_id);

        // Handle prior clients here
        if (m_clients.getProtocolVersion(peer_id) < 39) {
                pkt << params.bgcolor << params.type << (u16) params.textures.size();

                for (const std::string& texture : params.textures)
                        pkt << texture;

                pkt << params.clouds;
        } else { // Handle current clients and future clients
                pkt << params.bgcolor << params.type
                << params.clouds << params.fog_sun_tint
                << params.fog_moon_tint << params.fog_tint_type;

                if (params.type == "skybox") {
                        pkt << (u16) params.textures.size();
                        for (const std::string &texture : params.textures)
                                pkt << texture;
                } else if (params.type == "regular") {
                        pkt << params.sky_color.day_sky << params.sky_color.day_horizon
                                << params.sky_color.dawn_sky << params.sky_color.dawn_horizon
                                << params.sky_color.night_sky << params.sky_color.night_horizon
                                << params.sky_color.indoors;
                }
        }

        Send(&pkt);
}

void Server::SendSetSun(session_t peer_id, const SunParams &params)
{
        NetworkPacket pkt(TOCLIENT_SET_SUN, 0, peer_id);
        pkt << params.visible << params.texture
                << params.tonemap << params.sunrise
                << params.sunrise_visible << params.scale;

        Send(&pkt);
}
void Server::SendSetMoon(session_t peer_id, const MoonParams &params)
{
        NetworkPacket pkt(TOCLIENT_SET_MOON, 0, peer_id);

        pkt << params.visible << params.texture
                << params.tonemap << params.scale;

        Send(&pkt);
}
void Server::SendSetStars(session_t peer_id, const StarParams &params)
{
        NetworkPacket pkt(TOCLIENT_SET_STARS, 0, peer_id);

        pkt << params.visible << params.count
                << params.starcolor << params.scale;

        Send(&pkt);
}

void Server::SendCloudParams(session_t peer_id, const CloudParams &params)
{
        NetworkPacket pkt(TOCLIENT_CLOUD_PARAMS, 0, peer_id);
        pkt << params.density << params.color_bright << params.color_ambient
                        << params.height << params.thickness << params.speed;
        Send(&pkt);
}

void Server::SendOverrideDayNightRatio(session_t peer_id, bool do_override,
                float ratio)
{
        NetworkPacket pkt(TOCLIENT_OVERRIDE_DAY_NIGHT_RATIO,
                        1 + 2, peer_id);

        pkt << do_override << (u16) (ratio * 65535);

        Send(&pkt);
}

void Server::SendTimeOfDay(session_t peer_id, u16 time, f32 time_speed)
{
        NetworkPacket pkt(TOCLIENT_TIME_OF_DAY, 0, peer_id);
        pkt << time << time_speed;

        if (peer_id == PEER_ID_INEXISTENT) {
                m_clients.sendToAll(&pkt);
        }
        else {
                Send(&pkt);
        }
}

void Server::SendPlayerHP(session_t peer_id)
{
        PlayerSAO *playersao = getPlayerSAO(peer_id);
        assert(playersao);

        SendHP(peer_id, playersao->getHP());
        m_script->player_event(playersao,"health_changed");

        // Send to other clients
        playersao->sendPunchCommand();
}

void Server::SendPlayerBreath(PlayerSAO *sao)
{
        assert(sao);

        m_script->player_event(sao, "breath_changed");
        SendBreath(sao->getPeerID(), sao->getBreath());
}

void Server::SendMovePlayer(session_t peer_id)
{
        RemotePlayer *player = m_env->getPlayer(peer_id);
        assert(player);
        PlayerSAO *sao = player->getPlayerSAO();
        assert(sao);

        NetworkPacket pkt(TOCLIENT_MOVE_PLAYER, sizeof(v3f) + sizeof(f32) * 2, peer_id);
        pkt << sao->getBasePosition() << sao->getLookPitch() << sao->getRotation().Y;

        {
                v3f pos = sao->getBasePosition();
                verbosestream << "Server: Sending TOCLIENT_MOVE_PLAYER"
                                << " pos=(" << pos.X << "," << pos.Y << "," << pos.Z << ")"
                                << " pitch=" << sao->getLookPitch()
                                << " yaw=" << sao->getRotation().Y
                                << std::endl;
        }

        Send(&pkt);
}

void Server::SendPlayerFov(session_t peer_id)
{
        NetworkPacket pkt(TOCLIENT_FOV, 4 + 1 + 4, peer_id);

        PlayerFovSpec fov_spec = m_env->getPlayer(peer_id)->getFov();
        pkt << fov_spec.fov << fov_spec.is_multiplier << fov_spec.transition_time;

        Send(&pkt);
}

void Server::SendLocalPlayerAnimations(session_t peer_id, v2s32 animation_frames[4],
                f32 animation_speed)
{
        NetworkPacket pkt(TOCLIENT_LOCAL_PLAYER_ANIMATIONS, 0,
                peer_id);

        pkt << animation_frames[0] << animation_frames[1] << animation_frames[2]
                        << animation_frames[3] << animation_speed;

        Send(&pkt);
}

void Server::SendEyeOffset(session_t peer_id, v3f first, v3f third)
{
        NetworkPacket pkt(TOCLIENT_EYE_OFFSET, 0, peer_id);
        pkt << first << third;
        Send(&pkt);
}

void Server::SendPlayerPrivileges(session_t peer_id)
{
        RemotePlayer *player = m_env->getPlayer(peer_id);
        assert(player);
        if(player->getPeerId() == PEER_ID_INEXISTENT)
                return;

        std::set<std::string> privs;
        m_script->getAuth(player->getName(), NULL, &privs);

        NetworkPacket pkt(TOCLIENT_PRIVILEGES, 0, peer_id);
        pkt << (u16) privs.size();

        for (const std::string &priv : privs) {
                pkt << priv;
        }

        Send(&pkt);
}

void Server::SendPlayerInventoryFormspec(session_t peer_id)
{
        RemotePlayer *player = m_env->getPlayer(peer_id);
        assert(player);
        if (player->getPeerId() == PEER_ID_INEXISTENT)
                return;

        NetworkPacket pkt(TOCLIENT_INVENTORY_FORMSPEC, 0, peer_id);
        pkt.putLongString(player->inventory_formspec);

        Send(&pkt);
}

void Server::SendPlayerFormspecPrepend(session_t peer_id)
{
        RemotePlayer *player = m_env->getPlayer(peer_id);
        assert(player);
        if (player->getPeerId() == PEER_ID_INEXISTENT)
                return;

        NetworkPacket pkt(TOCLIENT_FORMSPEC_PREPEND, 0, peer_id);
        pkt << player->formspec_prepend;
        Send(&pkt);
}

void Server::SendActiveObjectRemoveAdd(RemoteClient *client, PlayerSAO *playersao)
{
        // Radius inside which objects are active
        static thread_local const s16 radius =
                g_settings->getS16("active_object_send_range_blocks") * MAP_BLOCKSIZE;

        // Radius inside which players are active
        static thread_local const bool is_transfer_limited =
                g_settings->exists("unlimited_player_transfer_distance") &&
                !g_settings->getBool("unlimited_player_transfer_distance");

        static thread_local const s16 player_transfer_dist =
                g_settings->getS16("player_transfer_distance") * MAP_BLOCKSIZE;

        s16 player_radius = player_transfer_dist == 0 && is_transfer_limited ?
                radius : player_transfer_dist;

        s16 my_radius = MYMIN(radius, playersao->getWantedRange() * MAP_BLOCKSIZE);
        if (my_radius <= 0)
                my_radius = radius;

        std::queue<u16> removed_objects, added_objects;
        m_env->getRemovedActiveObjects(playersao, my_radius, player_radius,
                client->m_known_objects, removed_objects);
        m_env->getAddedActiveObjects(playersao, my_radius, player_radius,
                client->m_known_objects, added_objects);

        int removed_count = removed_objects.size();
        int added_count   = added_objects.size();

        if (removed_objects.empty() && added_objects.empty())
                return;

        char buf[4];
        std::string data;

        // Handle removed objects
        writeU16((u8*)buf, removed_objects.size());
        data.append(buf, 2);
        while (!removed_objects.empty()) {
                // Get object
                u16 id = removed_objects.front();
                ServerActiveObject* obj = m_env->getActiveObject(id);

                // Add to data buffer for sending
                writeU16((u8*)buf, id);
                data.append(buf, 2);

                // Remove from known objects
                client->m_known_objects.erase(id);

                if (obj && obj->m_known_by_count > 0)
                        obj->m_known_by_count--;

                removed_objects.pop();
        }

        // Handle added objects
        writeU16((u8*)buf, added_objects.size());
        data.append(buf, 2);
        while (!added_objects.empty()) {
                // Get object
                u16 id = added_objects.front();
                ServerActiveObject *obj = m_env->getActiveObject(id);
                added_objects.pop();

                if (!obj) {
                        warningstream << FUNCTION_NAME << ": NULL object id="
                                << (int)id << std::endl;
                        continue;
                }

                // Get object type
                u8 type = obj->getSendType();

                // Add to data buffer for sending
                writeU16((u8*)buf, id);
                data.append(buf, 2);
                writeU8((u8*)buf, type);
                data.append(buf, 1);

                data.append(serializeString32(
                        obj->getClientInitializationData(client->net_proto_version)));

                // Add to known objects
                client->m_known_objects.insert(id);

                obj->m_known_by_count++;
        }

        NetworkPacket pkt(TOCLIENT_ACTIVE_OBJECT_REMOVE_ADD, data.size(), client->peer_id);
        pkt.putRawString(data.c_str(), data.size());
        Send(&pkt);

        verbosestream << "Server::SendActiveObjectRemoveAdd: "
                << removed_count << " removed, " << added_count << " added, "
                << "packet size is " << pkt.getSize() << std::endl;
}

void Server::SendActiveObjectMessages(session_t peer_id, const std::string &datas,
                bool reliable)
{
        NetworkPacket pkt(TOCLIENT_ACTIVE_OBJECT_MESSAGES,
                        datas.size(), peer_id);

        pkt.putRawString(datas.c_str(), datas.size());

        m_clients.send(pkt.getPeerId(),
                        reliable ? clientCommandFactoryTable[pkt.getCommand()].channel : 1,
                        &pkt, reliable);
}

void Server::SendCSMRestrictionFlags(session_t peer_id)
{
        NetworkPacket pkt(TOCLIENT_CSM_RESTRICTION_FLAGS,
                sizeof(m_csm_restriction_flags) + sizeof(m_csm_restriction_noderange), peer_id);
        pkt << m_csm_restriction_flags << m_csm_restriction_noderange;
        Send(&pkt);
}

void Server::SendPlayerSpeed(session_t peer_id, const v3f &added_vel)
{
        NetworkPacket pkt(TOCLIENT_PLAYER_SPEED, 0, peer_id);
        pkt << added_vel;
        Send(&pkt);
}

inline s32 Server::nextSoundId()
{
        s32 ret = m_next_sound_id;
        if (m_next_sound_id == INT32_MAX)
                m_next_sound_id = 0; // signed overflow is undefined
        else
                m_next_sound_id++;
        return ret;
}

s32 Server::playSound(const SimpleSoundSpec &spec,
                const ServerSoundParams &params, bool ephemeral)
{
        // Find out initial position of sound
        bool pos_exists = false;
        v3f pos = params.getPos(m_env, &pos_exists);
        // If position is not found while it should be, cancel sound
        if(pos_exists != (params.type != ServerSoundParams::SSP_LOCAL))
                return -1;

        // Filter destination clients
        std::vector<session_t> dst_clients;
        if (!params.to_player.empty()) {
                RemotePlayer *player = m_env->getPlayer(params.to_player.c_str());
                if(!player){
                        infostream<<"Server::playSound: Player \""<<params.to_player
                                        <<"\" not found"<<std::endl;
                        return -1;
                }
                if (player->getPeerId() == PEER_ID_INEXISTENT) {
                        infostream<<"Server::playSound: Player \""<<params.to_player
                                        <<"\" not connected"<<std::endl;
                        return -1;
                }
                dst_clients.push_back(player->getPeerId());
        } else {
                std::vector<session_t> clients = m_clients.getClientIDs();

                for (const session_t client_id : clients) {
                        RemotePlayer *player = m_env->getPlayer(client_id);
                        if (!player)
                                continue;
                        if (!params.exclude_player.empty() &&
                                        params.exclude_player == player->getName())
                                continue;

                        PlayerSAO *sao = player->getPlayerSAO();
                        if (!sao)
                                continue;

                        if (pos_exists) {
                                if(sao->getBasePosition().getDistanceFrom(pos) >
                                                params.max_hear_distance)
                                        continue;
                        }
                        dst_clients.push_back(client_id);
                }
        }

        if(dst_clients.empty())
                return -1;

        // Create the sound
        s32 id;
        ServerPlayingSound *psound = nullptr;
        if (ephemeral) {
                id = -1; // old clients will still use this, so pick a reserved ID
        } else {
                id = nextSoundId();
                // The sound will exist as a reference in m_playing_sounds
                m_playing_sounds[id] = ServerPlayingSound();
                psound = &m_playing_sounds[id];
                psound->params = params;
                psound->spec = spec;
        }

        float gain = params.gain * spec.gain;
        NetworkPacket pkt(TOCLIENT_PLAY_SOUND, 0);
        pkt << id << spec.name << gain
                        << (u8) params.type << pos << params.object
                        << params.loop << params.fade << params.pitch
                        << ephemeral;

        bool as_reliable = !ephemeral;

        for (const u16 dst_client : dst_clients) {
                if (psound)
                        psound->clients.insert(dst_client);
                m_clients.send(dst_client, 0, &pkt, as_reliable);
        }
        return id;
}
void Server::stopSound(s32 handle)
{
        // Get sound reference
        std::unordered_map<s32, ServerPlayingSound>::iterator i =
                m_playing_sounds.find(handle);
        if (i == m_playing_sounds.end())
                return;
        ServerPlayingSound &psound = i->second;

        NetworkPacket pkt(TOCLIENT_STOP_SOUND, 4);
        pkt << handle;

        for (std::unordered_set<session_t>::const_iterator si = psound.clients.begin();
                        si != psound.clients.end(); ++si) {
                // Send as reliable
                m_clients.send(*si, 0, &pkt, true);
        }
        // Remove sound reference
        m_playing_sounds.erase(i);
}

void Server::fadeSound(s32 handle, float step, float gain)
{
        // Get sound reference
        std::unordered_map<s32, ServerPlayingSound>::iterator i =
                m_playing_sounds.find(handle);
        if (i == m_playing_sounds.end())
                return;

        ServerPlayingSound &psound = i->second;
        psound.params.gain = gain;

        NetworkPacket pkt(TOCLIENT_FADE_SOUND, 4);
        pkt << handle << step << gain;

        // Backwards compability
        bool play_sound = gain > 0;
        ServerPlayingSound compat_psound = psound;
        compat_psound.clients.clear();

        NetworkPacket compat_pkt(TOCLIENT_STOP_SOUND, 4);
        compat_pkt << handle;

        for (std::unordered_set<u16>::iterator it = psound.clients.begin();
                        it != psound.clients.end();) {
                if (m_clients.getProtocolVersion(*it) >= 32) {
                        // Send as reliable
                        m_clients.send(*it, 0, &pkt, true);
                        ++it;
                } else {
                        compat_psound.clients.insert(*it);
                        // Stop old sound
                        m_clients.send(*it, 0, &compat_pkt, true);
                        psound.clients.erase(it++);
                }
        }

        // Remove sound reference
        if (!play_sound || psound.clients.empty())
                m_playing_sounds.erase(i);

        if (play_sound && !compat_psound.clients.empty()) {
                // Play new sound volume on older clients
                playSound(compat_psound.spec, compat_psound.params);
        }
}

void Server::sendRemoveNode(v3s16 p, std::unordered_set<u16> *far_players,
                float far_d_nodes)
{
        float maxd = far_d_nodes * BS;
        v3f p_f = intToFloat(p, BS);
        v3s16 block_pos = getNodeBlockPos(p);

        NetworkPacket pkt(TOCLIENT_REMOVENODE, 6);
        pkt << p;

        std::vector<session_t> clients = m_clients.getClientIDs();
        m_clients.lock();

        for (session_t client_id : clients) {
                RemoteClient *client = m_clients.lockedGetClientNoEx(client_id);
                if (!client)
                        continue;

                RemotePlayer *player = m_env->getPlayer(client_id);
                PlayerSAO *sao = player ? player->getPlayerSAO() : nullptr;

                // If player is far away, only set modified blocks not sent
                if (!client->isBlockSent(block_pos) || (sao &&
                                sao->getBasePosition().getDistanceFrom(p_f) > maxd)) {
                        if (far_players)
                                far_players->emplace(client_id);
                        else
                                client->SetBlockNotSent(block_pos);
                        continue;
                }

                // Send as reliable
                m_clients.send(client_id, 0, &pkt, true);
        }

        m_clients.unlock();
}

void Server::sendAddNode(v3s16 p, MapNode n, std::unordered_set<u16> *far_players,
                float far_d_nodes, bool remove_metadata)
{
        float maxd = far_d_nodes * BS;
        v3f p_f = intToFloat(p, BS);
        v3s16 block_pos = getNodeBlockPos(p);

        NetworkPacket pkt(TOCLIENT_ADDNODE, 6 + 2 + 1 + 1 + 1);
        pkt << p << n.param0 << n.param1 << n.param2
                        << (u8) (remove_metadata ? 0 : 1);

        std::vector<session_t> clients = m_clients.getClientIDs();
        m_clients.lock();

        for (session_t client_id : clients) {
                RemoteClient *client = m_clients.lockedGetClientNoEx(client_id);
                if (!client)
                        continue;

                RemotePlayer *player = m_env->getPlayer(client_id);
                PlayerSAO *sao = player ? player->getPlayerSAO() : nullptr;

                // If player is far away, only set modified blocks not sent
                if (!client->isBlockSent(block_pos) || (sao &&
                                sao->getBasePosition().getDistanceFrom(p_f) > maxd)) {
                        if (far_players)
                                far_players->emplace(client_id);
                        else
                                client->SetBlockNotSent(block_pos);
                        continue;
                }

                // Send as reliable
                m_clients.send(client_id, 0, &pkt, true);
        }

        m_clients.unlock();
}

void Server::sendMetadataChanged(const std::list<v3s16> &meta_updates, float far_d_nodes)
{
        float maxd = far_d_nodes * BS;
        NodeMetadataList meta_updates_list(false);
        std::vector<session_t> clients = m_clients.getClientIDs();

        m_clients.lock();

        for (session_t i : clients) {
                RemoteClient *client = m_clients.lockedGetClientNoEx(i);
                if (!client)
                        continue;

                ServerActiveObject *player = m_env->getActiveObject(i);
                v3f player_pos = player ? player->getBasePosition() : v3f();

                for (const v3s16 &pos : meta_updates) {
                        NodeMetadata *meta = m_env->getMap().getNodeMetadata(pos);

                        if (!meta)
                                continue;

                        v3s16 block_pos = getNodeBlockPos(pos);
                        if (!client->isBlockSent(block_pos) || (player &&
                                        player_pos.getDistanceFrom(intToFloat(pos, BS)) > maxd)) {
                                client->SetBlockNotSent(block_pos);
                                continue;
                        }

                        // Add the change to send list
                        meta_updates_list.set(pos, meta);
                }
                if (meta_updates_list.size() == 0)
                        continue;

                // Send the meta changes
                std::ostringstream os(std::ios::binary);
                meta_updates_list.serialize(os, client->net_proto_version, false, true);
                std::ostringstream oss(std::ios::binary);
                compressZlib(os.str(), oss);

                NetworkPacket pkt(TOCLIENT_NODEMETA_CHANGED, 0);
                pkt.putLongString(oss.str());
                m_clients.send(i, 0, &pkt, true);

                meta_updates_list.clear();
        }

        m_clients.unlock();
}

void Server::SendBlockNoLock(session_t peer_id, MapBlock *block, u8 ver,
                u16 net_proto_version)
{
        /*
                Create a packet with the block in the right format
        */

        std::ostringstream os(std::ios_base::binary);
        block->serialize(os, ver, false);
        block->serializeNetworkSpecific(os);
        std::string s = os.str();

        NetworkPacket pkt(TOCLIENT_BLOCKDATA, 2 + 2 + 2 + s.size(), peer_id);

        pkt << block->getPos();
        pkt.putRawString(s.c_str(), s.size());
        Send(&pkt);
}

void Server::SendBlocks(float dtime)
{
        MutexAutoLock envlock(m_env_mutex);
        //TODO check if one big lock could be faster then multiple small ones

        std::vector<PrioritySortedBlockTransfer> queue;

        u32 total_sending = 0;

        {
                ScopeProfiler sp2(g_profiler, "Server::SendBlocks(): Collect list");

                std::vector<session_t> clients = m_clients.getClientIDs();

                m_clients.lock();
                for (const session_t client_id : clients) {
                        RemoteClient *client = m_clients.lockedGetClientNoEx(client_id, CS_Active);

                        if (!client)
                                continue;

                        total_sending += client->getSendingCount();
                        client->GetNextBlocks(m_env,m_emerge, dtime, queue);
                }
                m_clients.unlock();
        }

        // Sort.
        // Lowest priority number comes first.
        // Lowest is most important.
        std::sort(queue.begin(), queue.end());

        m_clients.lock();

        // Maximal total count calculation
        // The per-client block sends is halved with the maximal online users
        u32 max_blocks_to_send = (m_env->getPlayerCount() + g_settings->getU32("max_users")) *
                g_settings->getU32("max_simultaneous_block_sends_per_client") / 4 + 1;

        ScopeProfiler sp(g_profiler, "Server::SendBlocks(): Send to clients");
        Map &map = m_env->getMap();

        for (const PrioritySortedBlockTransfer &block_to_send : queue) {
                if (total_sending >= max_blocks_to_send)
                        break;

                MapBlock *block = map.getBlockNoCreateNoEx(block_to_send.pos);
                if (!block)
                        continue;

                RemoteClient *client = m_clients.lockedGetClientNoEx(block_to_send.peer_id,
                                CS_Active);
                if (!client)
                        continue;

                SendBlockNoLock(block_to_send.peer_id, block, client->serialization_version,
                                client->net_proto_version);

                client->SentBlock(block_to_send.pos);
                total_sending++;
        }
        m_clients.unlock();
}

bool Server::SendBlock(session_t peer_id, const v3s16 &blockpos)
{
        MapBlock *block = m_env->getMap().getBlockNoCreateNoEx(blockpos);
        if (!block)
                return false;

        m_clients.lock();
        RemoteClient *client = m_clients.lockedGetClientNoEx(peer_id, CS_Active);
        if (!client || client->isBlockSent(blockpos)) {
                m_clients.unlock();
                return false;
        }
        SendBlockNoLock(peer_id, block, client->serialization_version,
                        client->net_proto_version);
        m_clients.unlock();

        return true;
}

bool Server::addMediaFile(const std::string &filename,
        const std::string &filepath, std::string *filedata_to,
        std::string *digest_to)
{
        // If name contains illegal characters, ignore the file
        if (!string_allowed(filename, TEXTURENAME_ALLOWED_CHARS)) {
                infostream << "Server: ignoring illegal file name: \""
                                << filename << "\"" << std::endl;
                return false;
        }
        // If name is not in a supported format, ignore it
        const char *supported_ext[] = {
                ".png", ".jpg", ".bmp", ".tga",
                ".pcx", ".ppm", ".psd", ".wal", ".rgb",
                ".ogg",
                ".x", ".b3d", ".md2", ".obj",
                // Custom translation file format
                ".tr",
                NULL
        };
        if (removeStringEnd(filename, supported_ext).empty()) {
                infostream << "Server: ignoring unsupported file extension: \""
                                << filename << "\"" << std::endl;
                return false;
        }
        // Ok, attempt to load the file and add to cache

        // Read data
        std::string filedata;
        if (!fs::ReadFile(filepath, filedata)) {
                errorstream << "Server::addMediaFile(): Failed to open \""
                                        << filename << "\" for reading" << std::endl;
                return false;
        }

        if (filedata.empty()) {
                errorstream << "Server::addMediaFile(): Empty file \""
                                << filepath << "\"" << std::endl;
                return false;
        }

        SHA1 sha1;
        sha1.addBytes(filedata.c_str(), filedata.length());

        unsigned char *digest = sha1.getDigest();
        std::string sha1_base64 = base64_encode(digest, 20);
        std::string sha1_hex = hex_encode((char*) digest, 20);
        if (digest_to)
                *digest_to = std::string((char*) digest, 20);
        free(digest);

        // Put in list
        m_media[filename] = MediaInfo(filepath, sha1_base64);
        verbosestream << "Server: " << sha1_hex << " is " << filename
                        << std::endl;

        if (filedata_to)
                *filedata_to = std::move(filedata);
        return true;
}

void Server::fillMediaCache()
{
        infostream << "Server: Calculating media file checksums" << std::endl;

        // Collect all media file paths
        std::vector<std::string> paths;
        // The paths are ordered in descending priority
        fs::GetRecursiveDirs(paths, porting::path_user + DIR_DELIM + "textures" + DIR_DELIM + "server");
        fs::GetRecursiveDirs(paths, m_gamespec.path + DIR_DELIM + "textures");
        m_modmgr->getModsMediaPaths(paths);

        // Collect media file information from paths into cache
        for (const std::string &mediapath : paths) {
                std::vector<fs::DirListNode> dirlist = fs::GetDirListing(mediapath);
                for (const fs::DirListNode &dln : dirlist) {
                        if (dln.dir) // Ignore dirs (already in paths)
                                continue;

                        const std::string &filename = dln.name;
                        if (m_media.find(filename) != m_media.end()) // Do not override
                                continue;

                        std::string filepath = mediapath;
                        filepath.append(DIR_DELIM).append(filename);
                        addMediaFile(filename, filepath);
                }
        }

        infostream << "Server: " << m_media.size() << " media files collected" << std::endl;
}

void Server::sendMediaAnnouncement(session_t peer_id, const std::string &lang_code)
{
        // Make packet
        NetworkPacket pkt(TOCLIENT_ANNOUNCE_MEDIA, 0, peer_id);

        u16 media_sent = 0;
        std::string lang_suffix;
        lang_suffix.append(".").append(lang_code).append(".tr");
        for (const auto &i : m_media) {
                if (str_ends_with(i.first, ".tr") && !str_ends_with(i.first, lang_suffix))
                        continue;
                media_sent++;
        }

        pkt << media_sent;

        for (const auto &i : m_media) {
                if (str_ends_with(i.first, ".tr") && !str_ends_with(i.first, lang_suffix))
                        continue;
                pkt << i.first << i.second.sha1_digest;
        }

        pkt << g_settings->get("remote_media");
        Send(&pkt);

        verbosestream << "Server: Announcing files to id(" << peer_id
                << "): count=" << media_sent << " size=" << pkt.getSize() << std::endl;
}

struct SendableMedia
{
        std::string name;
        std::string path;
        std::string data;

        SendableMedia(const std::string &name_="", const std::string &path_="",
                      const std::string &data_=""):
                name(name_),
                path(path_),
                data(data_)
        {}
};

void Server::sendRequestedMedia(session_t peer_id,
                const std::vector<std::string> &tosend)
{
        verbosestream<<"Server::sendRequestedMedia(): "
                        <<"Sending files to client"<<std::endl;

        /* Read files */

        // Put 5kB in one bunch (this is not accurate)
        u32 bytes_per_bunch = 5000;

        std::vector< std::vector<SendableMedia> > file_bunches;
        file_bunches.emplace_back();

        u32 file_size_bunch_total = 0;

        for (const std::string &name : tosend) {
                if (m_media.find(name) == m_media.end()) {
                        errorstream<<"Server::sendRequestedMedia(): Client asked for "
                                        <<"unknown file \""<<(name)<<"\""<<std::endl;
                        continue;
                }

                //TODO get path + name
                std::string tpath = m_media[name].path;

                // Read data
                std::ifstream fis(tpath.c_str(), std::ios_base::binary);
                if(!fis.good()){
                        errorstream<<"Server::sendRequestedMedia(): Could not open \""
                                        <<tpath<<"\" for reading"<<std::endl;
                        continue;
                }
                std::ostringstream tmp_os(std::ios_base::binary);
                bool bad = false;
                for(;;) {
                        char buf[1024];
                        fis.read(buf, 1024);
                        std::streamsize len = fis.gcount();
                        tmp_os.write(buf, len);
                        file_size_bunch_total += len;
                        if(fis.eof())
                                break;
                        if(!fis.good()) {
                                bad = true;
                                break;
                        }
                }
                if (bad) {
                        errorstream<<"Server::sendRequestedMedia(): Failed to read \""
                                        <<name<<"\""<<std::endl;
                        continue;
                }
                /*infostream<<"Server::sendRequestedMedia(): Loaded \""
                                <<tname<<"\""<<std::endl;*/
                // Put in list
                file_bunches[file_bunches.size()-1].emplace_back(name, tpath, tmp_os.str());

                // Start next bunch if got enough data
                if(file_size_bunch_total >= bytes_per_bunch) {
                        file_bunches.emplace_back();
                        file_size_bunch_total = 0;
                }

        }

        /* Create and send packets */

        u16 num_bunches = file_bunches.size();
        for (u16 i = 0; i < num_bunches; i++) {
                /*
                        u16 command
                        u16 total number of texture bunches
                        u16 index of this bunch
                        u32 number of files in this bunch
                        for each file {
                                u16 length of name
                                string name
                                u32 length of data
                                data
                        }
                */

                NetworkPacket pkt(TOCLIENT_MEDIA, 4 + 0, peer_id);
                pkt << num_bunches << i << (u32) file_bunches[i].size();

                for (const SendableMedia &j : file_bunches[i]) {
                        pkt << j.name;
                        pkt.putLongString(j.data);
                }

                verbosestream << "Server::sendRequestedMedia(): bunch "
                                << i << "/" << num_bunches
                                << " files=" << file_bunches[i].size()
                                << " size="  << pkt.getSize() << std::endl;
                Send(&pkt);
        }
}

void Server::SendMinimapModes(session_t peer_id,
                std::vector<MinimapMode> &modes, size_t wanted_mode)
{
        RemotePlayer *player = m_env->getPlayer(peer_id);
        assert(player);
        if (player->getPeerId() == PEER_ID_INEXISTENT)
                return;

        NetworkPacket pkt(TOCLIENT_MINIMAP_MODES, 0, peer_id);
        pkt << (u16)modes.size() << (u16)wanted_mode;

        for (auto &mode : modes)
                pkt << (u16)mode.type << mode.label << mode.size << mode.texture << mode.scale;

        Send(&pkt);
}

void Server::sendDetachedInventory(Inventory *inventory, const std::string &name, session_t peer_id)
{
        NetworkPacket pkt(TOCLIENT_DETACHED_INVENTORY, 0, peer_id);
        pkt << name;

        if (!inventory) {
                pkt << false; // Remove inventory
        } else {
                pkt << true; // Update inventory

                // Serialization & NetworkPacket isn't a love story
                std::ostringstream os(std::ios_base::binary);
                inventory->serialize(os);
                inventory->setModified(false);

                const std::string &os_str = os.str();
                pkt << static_cast<u16>(os_str.size()); // HACK: to keep compatibility with 5.0.0 clients
                pkt.putRawString(os_str);
        }

        if (peer_id == PEER_ID_INEXISTENT)
                m_clients.sendToAll(&pkt);
        else
                Send(&pkt);
}

void Server::sendDetachedInventories(session_t peer_id, bool incremental)
{
        // Lookup player name, to filter detached inventories just after
        std::string peer_name;
        if (peer_id != PEER_ID_INEXISTENT) {
                peer_name = getClient(peer_id, CS_Created)->getName();
        }

        auto send_cb = [this, peer_id](const std::string &name, Inventory *inv) {
                sendDetachedInventory(inv, name, peer_id);
        };

        m_inventory_mgr->sendDetachedInventories(peer_name, incremental, send_cb);
}

/*
        Something random
*/

void Server::DiePlayer(session_t peer_id, const PlayerHPChangeReason &reason)
{
        PlayerSAO *playersao = getPlayerSAO(peer_id);
        assert(playersao);

        infostream << "Server::DiePlayer(): Player "
                        << playersao->getPlayer()->getName()
                        << " dies" << std::endl;

        playersao->setHP(0, reason);
        playersao->clearParentAttachment();

        // Trigger scripted stuff
        m_script->on_dieplayer(playersao, reason);

        SendPlayerHP(peer_id);
        SendDeathscreen(peer_id, false, v3f(0,0,0));
}

void Server::RespawnPlayer(session_t peer_id)
{
        PlayerSAO *playersao = getPlayerSAO(peer_id);
        assert(playersao);

        infostream << "Server::RespawnPlayer(): Player "
                        << playersao->getPlayer()->getName()
                        << " respawns" << std::endl;

        playersao->setHP(playersao->accessObjectProperties()->hp_max,
                        PlayerHPChangeReason(PlayerHPChangeReason::RESPAWN));
        playersao->setBreath(playersao->accessObjectProperties()->breath_max);

        bool repositioned = m_script->on_respawnplayer(playersao);
        if (!repositioned) {
                // setPos will send the new position to client
                playersao->setPos(findSpawnPos());
        }

        SendPlayerHP(peer_id);
}


void Server::DenySudoAccess(session_t peer_id)
{
        NetworkPacket pkt(TOCLIENT_DENY_SUDO_MODE, 0, peer_id);
        Send(&pkt);
}


void Server::DenyAccessVerCompliant(session_t peer_id, u16 proto_ver, AccessDeniedCode reason,
                const std::string &str_reason, bool reconnect)
{
        SendAccessDenied(peer_id, reason, str_reason, reconnect);

        m_clients.event(peer_id, CSE_SetDenied);
        DisconnectPeer(peer_id);
}


void Server::DenyAccess(session_t peer_id, AccessDeniedCode reason,
                const std::string &custom_reason)
{
        SendAccessDenied(peer_id, reason, custom_reason);
        m_clients.event(peer_id, CSE_SetDenied);
        DisconnectPeer(peer_id);
}

// 13/03/15: remove this function when protocol version 25 will become
// the minimum version for MT users, maybe in 1 year
void Server::DenyAccess_Legacy(session_t peer_id, const std::wstring &reason)
{
        SendAccessDenied_Legacy(peer_id, reason);
        m_clients.event(peer_id, CSE_SetDenied);
        DisconnectPeer(peer_id);
}

void Server::DisconnectPeer(session_t peer_id)
{
        m_modchannel_mgr->leaveAllChannels(peer_id);
        m_con->DisconnectPeer(peer_id);
}

void Server::acceptAuth(session_t peer_id, bool forSudoMode)
{
        if (!forSudoMode) {
                RemoteClient* client = getClient(peer_id, CS_Invalid);

                NetworkPacket resp_pkt(TOCLIENT_AUTH_ACCEPT, 1 + 6 + 8 + 4, peer_id);

                // Right now, the auth mechs don't change between login and sudo mode.
                u32 sudo_auth_mechs = client->allowed_auth_mechs;
                client->allowed_sudo_mechs = sudo_auth_mechs;

                resp_pkt << v3f(0,0,0) << (u64) m_env->getServerMap().getSeed()
                                << g_settings->getFloat("dedicated_server_step")
                                << sudo_auth_mechs;

                Send(&resp_pkt);
                m_clients.event(peer_id, CSE_AuthAccept);
        } else {
                NetworkPacket resp_pkt(TOCLIENT_ACCEPT_SUDO_MODE, 1 + 6 + 8 + 4, peer_id);

                // We only support SRP right now
                u32 sudo_auth_mechs = AUTH_MECHANISM_FIRST_SRP;

                resp_pkt << sudo_auth_mechs;
                Send(&resp_pkt);
                m_clients.event(peer_id, CSE_SudoSuccess);
        }
}

void Server::DeleteClient(session_t peer_id, ClientDeletionReason reason)
{
        std::wstring message;
        {
                /*
                        Clear references to playing sounds
                */
                for (std::unordered_map<s32, ServerPlayingSound>::iterator
                                 i = m_playing_sounds.begin(); i != m_playing_sounds.end();) {
                        ServerPlayingSound &psound = i->second;
                        psound.clients.erase(peer_id);
                        if (psound.clients.empty())
                                m_playing_sounds.erase(i++);
                        else
                                ++i;
                }

                // clear formspec info so the next client can't abuse the current state
                m_formspec_state_data.erase(peer_id);

                RemotePlayer *player = m_env->getPlayer(peer_id);

                /* Run scripts and remove from environment */
                if (player) {
                        PlayerSAO *playersao = player->getPlayerSAO();
                        assert(playersao);

                        playersao->clearChildAttachments();
                        playersao->clearParentAttachment();

                        // inform connected clients
                        const std::string &player_name = player->getName();
                        NetworkPacket notice(TOCLIENT_UPDATE_PLAYER_LIST, 0, PEER_ID_INEXISTENT);
                        // (u16) 1 + std::string represents a vector serialization representation
                        notice << (u8) PLAYER_LIST_REMOVE  << (u16) 1 << player_name;
                        m_clients.sendToAll(&notice);
                        // run scripts
                        m_script->on_leaveplayer(playersao, reason == CDR_TIMEOUT);

                        playersao->disconnected();
                }

                /*
                        Print out action
                */
                {
                        if (player && reason != CDR_DENY) {
                                std::ostringstream os(std::ios_base::binary);
                                std::vector<session_t> clients = m_clients.getClientIDs();

                                for (const session_t client_id : clients) {
                                        // Get player
                                        RemotePlayer *player = m_env->getPlayer(client_id);
                                        if (!player)
                                                continue;

                                        // Get name of player
                                        os << player->getName() << " ";
                                }

                                std::string name = player->getName();
                                actionstream << name << " "
                                                << (reason == CDR_TIMEOUT ? "times out." : "leaves game.")
                                                << " List of players: " << os.str() << std::endl;
                                if (m_admin_chat)
                                        m_admin_chat->outgoing_queue.push_back(
                                                new ChatEventNick(CET_NICK_REMOVE, name));
                        }
                }
                {
                        MutexAutoLock env_lock(m_env_mutex);
                        m_clients.DeleteClient(peer_id);
                }
        }

        // Send leave chat message to all remaining clients
        if (!message.empty()) {
                SendChatMessage(PEER_ID_INEXISTENT,
                                ChatMessage(CHATMESSAGE_TYPE_ANNOUNCE, message));
        }
}

void Server::UpdateCrafting(RemotePlayer *player)
{
        InventoryList *clist = player->inventory.getList("craft");
        if (!clist || clist->getSize() == 0)
                return;

        if (!clist->checkModified())
                return;

        // Get a preview for crafting
        ItemStack preview;
        InventoryLocation loc;
        loc.setPlayer(player->getName());
        std::vector<ItemStack> output_replacements;
        getCraftingResult(&player->inventory, preview, output_replacements, false, this);
        m_env->getScriptIface()->item_CraftPredict(preview, player->getPlayerSAO(),
                        clist, loc);

        InventoryList *plist = player->inventory.getList("craftpreview");
        if (plist && plist->getSize() >= 1) {
                // Put the new preview in
                plist->changeItem(0, preview);
        }
}

void Server::handleChatInterfaceEvent(ChatEvent *evt)
{
        if (evt->type == CET_NICK_ADD) {
                // The terminal informed us of its nick choice
                m_admin_nick = ((ChatEventNick *)evt)->nick;
                if (!m_script->getAuth(m_admin_nick, NULL, NULL)) {
                        errorstream << "You haven't set up an account." << std::endl
                                << "Please log in using the client as '"
                                << m_admin_nick << "' with a secure password." << std::endl
                                << "Until then, you can't execute admin tasks via the console," << std::endl
                                << "and everybody can claim the user account instead of you," << std::endl
                                << "giving them full control over this server." << std::endl;
                }
        } else {
                assert(evt->type == CET_CHAT);
                handleAdminChat((ChatEventChat *)evt);
        }
}

std::wstring Server::handleChat(const std::string &name, const std::wstring &wname,
        std::wstring wmessage, bool check_shout_priv, RemotePlayer *player)
{
        // If something goes wrong, this player is to blame
        RollbackScopeActor rollback_scope(m_rollback,
                        std::string("player:") + name);

        if (g_settings->getBool("strip_color_codes"))
                wmessage = unescape_enriched(wmessage);

        if (player) {
                switch (player->canSendChatMessage()) {
                case RPLAYER_CHATRESULT_FLOODING: {
                        std::wstringstream ws;
                        ws << L"You cannot send more messages. You are limited to "
                                        << g_settings->getFloat("chat_message_limit_per_10sec")
                                        << L" messages per 10 seconds.";
                        return ws.str();
                }
                case RPLAYER_CHATRESULT_KICK:
                        DenyAccess_Legacy(player->getPeerId(),
                                        L"You have been kicked due to message flooding.");
                        return L"";
                case RPLAYER_CHATRESULT_OK:
                        break;
                default:
                        FATAL_ERROR("Unhandled chat filtering result found.");
                }
        }

        if (m_max_chatmessage_length > 0
                        && wmessage.length() > m_max_chatmessage_length) {
                return L"Your message exceed the maximum chat message limit set on the server. "
                                L"It was refused. Send a shorter message";
        }

        auto message = trim(wide_to_utf8(wmessage));
        if (message.find_first_of("\n\r") != std::wstring::npos) {
                return L"New lines are not permitted in chat messages";
        }

        // Run script hook, exit if script ate the chat message
        if (m_script->on_chat_message(name, message))
                return L"";

        // Line to send
        std::wstring line;
        // Whether to send line to the player that sent the message, or to all players
        bool broadcast_line = true;

        if (check_shout_priv && !checkPriv(name, "shout")) {
                line += L"-!- You don't have permission to shout.";
                broadcast_line = false;
        } else {
                /*
                        Workaround for fixing chat on Android. Lua doesn't handle
                        the Cyrillic alphabet and some characters on older Android devices
                */
#ifdef __ANDROID__
                line += L"<" + wname + L"> " + wmessage;
#else
                line += narrow_to_wide(m_script->formatChatMessage(name,
                                wide_to_narrow(wmessage)));
#endif
        }

        /*
                Tell calling method to send the message to sender
        */
        if (!broadcast_line)
                return line;

        /*
                Send the message to others
        */
        actionstream << "CHAT: " << wide_to_narrow(unescape_enriched(line)) << std::endl;

        std::vector<session_t> clients = m_clients.getClientIDs();

        /*
                Send the message back to the inital sender
                if they are using protocol version >= 29
        */

        session_t peer_id_to_avoid_sending =
                (player ? player->getPeerId() : PEER_ID_INEXISTENT);

        if (player && player->protocol_version >= 29)
                peer_id_to_avoid_sending = PEER_ID_INEXISTENT;

        for (u16 cid : clients) {
                if (cid != peer_id_to_avoid_sending)
                        SendChatMessage(cid, ChatMessage(line));
        }
        return L"";
}

void Server::handleAdminChat(const ChatEventChat *evt)
{
        std::string name = evt->nick;
        std::wstring wname = utf8_to_wide(name);
        std::wstring wmessage = evt->evt_msg;

        std::wstring answer = handleChat(name, wname, wmessage);

        // If asked to send answer to sender
        if (!answer.empty()) {
                m_admin_chat->outgoing_queue.push_back(new ChatEventChat("", answer));
        }
}

RemoteClient *Server::getClient(session_t peer_id, ClientState state_min)
{
        RemoteClient *client = getClientNoEx(peer_id,state_min);
        if(!client)
                throw ClientNotFoundException("Client not found");

        return client;
}
RemoteClient *Server::getClientNoEx(session_t peer_id, ClientState state_min)
{
        return m_clients.getClientNoEx(peer_id, state_min);
}

std::string Server::getPlayerName(session_t peer_id)
{
        RemotePlayer *player = m_env->getPlayer(peer_id);
        if (!player)
                return "[id="+itos(peer_id)+"]";
        return player->getName();
}

PlayerSAO *Server::getPlayerSAO(session_t peer_id)
{
        RemotePlayer *player = m_env->getPlayer(peer_id);
        if (!player)
                return NULL;
        return player->getPlayerSAO();
}

std::wstring Server::getStatusString()
{
        std::wostringstream os(std::ios_base::binary);
        os << L"# Server: ";
        // Version
        os << L"version=" << narrow_to_wide(g_version_string);
        // Uptime
        os << L", uptime=" << m_uptime_counter->get();
        // Max lag estimate
        os << L", max_lag=" << (m_env ? m_env->getMaxLagEstimate() : 0);

        // Information about clients
        bool first = true;
        os << L", clients={";
        if (m_env) {
                std::vector<session_t> clients = m_clients.getClientIDs();
                for (session_t client_id : clients) {
                        RemotePlayer *player = m_env->getPlayer(client_id);

                        // Get name of player
                        std::wstring name = L"unknown";
                        if (player)
                                name = narrow_to_wide(player->getName());

                        // Add name to information string
                        if (!first)
                                os << L", ";
                        else
                                first = false;

                        os << name;
                }
        }
        os << L"}";

        if (m_env && !((ServerMap*)(&m_env->getMap()))->isSavingEnabled())
                os << std::endl << L"# Server: " << " WARNING: Map saving is disabled.";

        if (!g_settings->get("motd").empty())
                os << std::endl << L"# Server: " << narrow_to_wide(g_settings->get("motd"));

        return os.str();
}

std::set<std::string> Server::getPlayerEffectivePrivs(const std::string &name)
{
        std::set<std::string> privs;
        m_script->getAuth(name, NULL, &privs);
        return privs;
}

bool Server::checkPriv(const std::string &name, const std::string &priv)
{
        std::set<std::string> privs = getPlayerEffectivePrivs(name);
        return (privs.count(priv) != 0);
}

void Server::reportPrivsModified(const std::string &name)
{
        if (name.empty()) {
                std::vector<session_t> clients = m_clients.getClientIDs();
                for (const session_t client_id : clients) {
                        RemotePlayer *player = m_env->getPlayer(client_id);
                        reportPrivsModified(player->getName());
                }
        } else {
                RemotePlayer *player = m_env->getPlayer(name.c_str());
                if (!player)
                        return;
                SendPlayerPrivileges(player->getPeerId());
                PlayerSAO *sao = player->getPlayerSAO();
                if(!sao)
                        return;
                sao->updatePrivileges(
                                getPlayerEffectivePrivs(name),
                                isSingleplayer());
        }
}

void Server::reportInventoryFormspecModified(const std::string &name)
{
        RemotePlayer *player = m_env->getPlayer(name.c_str());
        if (!player)
                return;
        SendPlayerInventoryFormspec(player->getPeerId());
}

void Server::reportFormspecPrependModified(const std::string &name)
{
        RemotePlayer *player = m_env->getPlayer(name.c_str());
        if (!player)
                return;
        SendPlayerFormspecPrepend(player->getPeerId());
}

void Server::setIpBanned(const std::string &ip, const std::string &name)
{
        m_banmanager->add(ip, name);
}

void Server::unsetIpBanned(const std::string &ip_or_name)
{
        m_banmanager->remove(ip_or_name);
}

std::string Server::getBanDescription(const std::string &ip_or_name)
{
        return m_banmanager->getBanDescription(ip_or_name);
}

void Server::notifyPlayer(const char *name, const std::wstring &msg)
{
        // m_env will be NULL if the server is initializing
        if (!m_env)
                return;

        if (m_admin_nick == name && !m_admin_nick.empty()) {
                m_admin_chat->outgoing_queue.push_back(new ChatEventChat("", msg));
        }

        RemotePlayer *player = m_env->getPlayer(name);
        if (!player) {
                return;
        }

        if (player->getPeerId() == PEER_ID_INEXISTENT)
                return;

        SendChatMessage(player->getPeerId(), ChatMessage(msg));
}

bool Server::showFormspec(const char *playername, const std::string &formspec,
        const std::string &formname)
{
        // m_env will be NULL if the server is initializing
        if (!m_env)
                return false;

        RemotePlayer *player = m_env->getPlayer(playername);
        if (!player)
                return false;

        SendShowFormspecMessage(player->getPeerId(), formspec, formname);
        return true;
}

u32 Server::hudAdd(RemotePlayer *player, HudElement *form)
{
        if (!player)
                return -1;

        u32 id = player->addHud(form);

        SendHUDAdd(player->getPeerId(), id, form);

        return id;
}

bool Server::hudRemove(RemotePlayer *player, u32 id) {
        if (!player)
                return false;

        HudElement* todel = player->removeHud(id);

        if (!todel)
                return false;

        delete todel;

        SendHUDRemove(player->getPeerId(), id);
        return true;
}

bool Server::hudChange(RemotePlayer *player, u32 id, HudElementStat stat, void *data)
{
        if (!player)
                return false;

        SendHUDChange(player->getPeerId(), id, stat, data);
        return true;
}

bool Server::hudSetFlags(RemotePlayer *player, u32 flags, u32 mask)
{
        if (!player)
                return false;

        SendHUDSetFlags(player->getPeerId(), flags, mask);
        player->hud_flags &= ~mask;
        player->hud_flags |= flags;

        PlayerSAO* playersao = player->getPlayerSAO();

        if (!playersao)
                return false;

        m_script->player_event(playersao, "hud_changed");
        return true;
}

bool Server::hudSetHotbarItemcount(RemotePlayer *player, s32 hotbar_itemcount)
{
        if (!player)
                return false;

        if (hotbar_itemcount <= 0 || hotbar_itemcount > HUD_HOTBAR_ITEMCOUNT_MAX)
                return false;

        player->setHotbarItemcount(hotbar_itemcount);
        std::ostringstream os(std::ios::binary);
        writeS32(os, hotbar_itemcount);
        SendHUDSetParam(player->getPeerId(), HUD_PARAM_HOTBAR_ITEMCOUNT, os.str());
        return true;
}

void Server::hudSetHotbarImage(RemotePlayer *player, const std::string &name)
{
        if (!player)
                return;

        player->setHotbarImage(name);
        SendHUDSetParam(player->getPeerId(), HUD_PARAM_HOTBAR_IMAGE, name);
}

void Server::hudSetHotbarSelectedImage(RemotePlayer *player, const std::string &name)
{
        if (!player)
                return;

        player->setHotbarSelectedImage(name);
        SendHUDSetParam(player->getPeerId(), HUD_PARAM_HOTBAR_SELECTED_IMAGE, name);
}

Address Server::getPeerAddress(session_t peer_id)
{
        return m_con->GetPeerAddress(peer_id);
}

void Server::setLocalPlayerAnimations(RemotePlayer *player,
                v2s32 animation_frames[4], f32 frame_speed)
{
        sanity_check(player);
        player->setLocalAnimations(animation_frames, frame_speed);
        SendLocalPlayerAnimations(player->getPeerId(), animation_frames, frame_speed);
}

void Server::setPlayerEyeOffset(RemotePlayer *player, const v3f &first, const v3f &third)
{
        sanity_check(player);
        player->eye_offset_first = first;
        player->eye_offset_third = third;
        SendEyeOffset(player->getPeerId(), first, third);
}

void Server::setSky(RemotePlayer *player, const SkyboxParams &params)
{
        sanity_check(player);
        player->setSky(params);
        SendSetSky(player->getPeerId(), params);
}

void Server::setSun(RemotePlayer *player, const SunParams &params)
{
        sanity_check(player);
        player->setSun(params);
        SendSetSun(player->getPeerId(), params);
}

void Server::setMoon(RemotePlayer *player, const MoonParams &params)
{
        sanity_check(player);
        player->setMoon(params);
        SendSetMoon(player->getPeerId(), params);
}

void Server::setStars(RemotePlayer *player, const StarParams &params)
{
        sanity_check(player);
        player->setStars(params);
        SendSetStars(player->getPeerId(), params);
}

void Server::setClouds(RemotePlayer *player, const CloudParams &params)
{
        sanity_check(player);
        player->setCloudParams(params);
        SendCloudParams(player->getPeerId(), params);
}

void Server::overrideDayNightRatio(RemotePlayer *player, bool do_override,
        float ratio)
{
        sanity_check(player);
        player->overrideDayNightRatio(do_override, ratio);
        SendOverrideDayNightRatio(player->getPeerId(), do_override, ratio);
}

void Server::notifyPlayers(const std::wstring &msg)
{
        SendChatMessage(PEER_ID_INEXISTENT, ChatMessage(msg));
}

void Server::spawnParticle(const std::string &playername,
        const ParticleParameters &p)
{
        // m_env will be NULL if the server is initializing
        if (!m_env)
                return;

        session_t peer_id = PEER_ID_INEXISTENT;
        u16 proto_ver = 0;
        if (!playername.empty()) {
                RemotePlayer *player = m_env->getPlayer(playername.c_str());
                if (!player)
                        return;
                peer_id = player->getPeerId();
                proto_ver = player->protocol_version;
        }

        SendSpawnParticle(peer_id, proto_ver, p);
}

u32 Server::addParticleSpawner(const ParticleSpawnerParameters &p,
        ServerActiveObject *attached, const std::string &playername)
{
        // m_env will be NULL if the server is initializing
        if (!m_env)
                return -1;

        session_t peer_id = PEER_ID_INEXISTENT;
        u16 proto_ver = 0;
        if (!playername.empty()) {
                RemotePlayer *player = m_env->getPlayer(playername.c_str());
                if (!player)
                        return -1;
                peer_id = player->getPeerId();
                proto_ver = player->protocol_version;
        }

        u16 attached_id = attached ? attached->getId() : 0;

        u32 id;
        if (attached_id == 0)
                id = m_env->addParticleSpawner(p.time);
        else
                id = m_env->addParticleSpawner(p.time, attached_id);

        SendAddParticleSpawner(peer_id, proto_ver, p, attached_id, id);
        return id;
}

void Server::deleteParticleSpawner(const std::string &playername, u32 id)
{
        // m_env will be NULL if the server is initializing
        if (!m_env)
                throw ServerError("Can't delete particle spawners during initialisation!");

        session_t peer_id = PEER_ID_INEXISTENT;
        if (!playername.empty()) {
                RemotePlayer *player = m_env->getPlayer(playername.c_str());
                if (!player)
                        return;
                peer_id = player->getPeerId();
        }

        m_env->deleteParticleSpawner(id);
        SendDeleteParticleSpawner(peer_id, id);
}

bool Server::dynamicAddMedia(const std::string &filepath)
{
        std::string filename = fs::GetFilenameFromPath(filepath.c_str());
        if (m_media.find(filename) != m_media.end()) {
                errorstream << "Server::dynamicAddMedia(): file \"" << filename
                        << "\" already exists in media cache" << std::endl;
                return false;
        }

        // Load the file and add it to our media cache
        std::string filedata, raw_hash;
        bool ok = addMediaFile(filename, filepath, &filedata, &raw_hash);
        if (!ok)
                return false;

        // Push file to existing clients
        NetworkPacket pkt(TOCLIENT_MEDIA_PUSH, 0);
        pkt << raw_hash << filename << (bool) true;
        pkt.putLongString(filedata);

        auto client_ids = m_clients.getClientIDs(CS_DefinitionsSent);
        for (session_t client_id : client_ids) {
                /*
                        The network layer only guarantees ordered delivery inside a channel.
                        Since the very next packet could be one that uses the media, we have
                        to push the media over ALL channels to ensure it is processed before
                        it is used.
                        In practice this means we have to send it twice:
                        - channel 1 (HUD)
                        - channel 0 (everything else: e.g. play_sound, object messages)
                */
                m_clients.send(client_id, 1, &pkt, true);
                m_clients.send(client_id, 0, &pkt, true);
        }

        return true;
}

// actions: time-reversed list
// Return value: success/failure
bool Server::rollbackRevertActions(const std::list<RollbackAction> &actions,
                std::list<std::string> *log)
{
        infostream<<"Server::rollbackRevertActions(len="<<actions.size()<<")"<<std::endl;
        ServerMap *map = (ServerMap*)(&m_env->getMap());

        // Fail if no actions to handle
        if (actions.empty()) {
                assert(log);
                log->push_back("Nothing to do.");
                return false;
        }

        int num_tried = 0;
        int num_failed = 0;

        for (const RollbackAction &action : actions) {
                num_tried++;
                bool success = action.applyRevert(map, m_inventory_mgr.get(), this);
                if(!success){
                        num_failed++;
                        std::ostringstream os;
                        os<<"Revert of step ("<<num_tried<<") "<<action.toString()<<" failed";
                        infostream<<"Map::rollbackRevertActions(): "<<os.str()<<std::endl;
                        if (log)
                                log->push_back(os.str());
                }else{
                        std::ostringstream os;
                        os<<"Successfully reverted step ("<<num_tried<<") "<<action.toString();
                        infostream<<"Map::rollbackRevertActions(): "<<os.str()<<std::endl;
                        if (log)
                                log->push_back(os.str());
                }
        }

        infostream<<"Map::rollbackRevertActions(): "<<num_failed<<"/"<<num_tried
                        <<" failed"<<std::endl;

        // Call it done if less than half failed
        return num_failed <= num_tried/2;
}

// IGameDef interface
// Under envlock
IItemDefManager *Server::getItemDefManager()
{
        return m_itemdef;
}

const NodeDefManager *Server::getNodeDefManager()
{
        return m_nodedef;
}

ICraftDefManager *Server::getCraftDefManager()
{
        return m_craftdef;
}

u16 Server::allocateUnknownNodeId(const std::string &name)
{
        return m_nodedef->allocateDummy(name);
}

IWritableItemDefManager *Server::getWritableItemDefManager()
{
        return m_itemdef;
}

NodeDefManager *Server::getWritableNodeDefManager()
{
        return m_nodedef;
}

IWritableCraftDefManager *Server::getWritableCraftDefManager()
{
        return m_craftdef;
}

const std::vector<ModSpec> & Server::getMods() const
{
        return m_modmgr->getMods();
}

const ModSpec *Server::getModSpec(const std::string &modname) const
{
        return m_modmgr->getModSpec(modname);
}

void Server::getModNames(std::vector<std::string> &modlist)
{
        m_modmgr->getModNames(modlist);
}

std::string Server::getBuiltinLuaPath()
{
        return porting::path_share + DIR_DELIM + "builtin";
}

std::string Server::getModStoragePath() const
{
        return m_path_world + DIR_DELIM + "mod_storage";
}

v3f Server::findSpawnPos()
{
        ServerMap &map = m_env->getServerMap();
        v3f nodeposf;
        if (g_settings->getV3FNoEx("static_spawnpoint", nodeposf))
                return nodeposf * BS;

        bool is_good = false;
        // Limit spawn range to mapgen edges (determined by 'mapgen_limit')
        s32 range_max = map.getMapgenParams()->getSpawnRangeMax();

        // Try to find a good place a few times
        for (s32 i = 0; i < 4000 && !is_good; i++) {
                s32 range = MYMIN(1 + i, range_max);
                // We're going to try to throw the player to this position
                v2s16 nodepos2d = v2s16(
                        -range + (myrand() % (range * 2)),
                        -range + (myrand() % (range * 2)));
                // Get spawn level at point
                s16 spawn_level = m_emerge->getSpawnLevelAtPoint(nodepos2d);
                // Continue if MAX_MAP_GENERATION_LIMIT was returned by the mapgen to
                // signify an unsuitable spawn position, or if outside limits.
                if (spawn_level >= MAX_MAP_GENERATION_LIMIT ||
                                spawn_level <= -MAX_MAP_GENERATION_LIMIT)
                        continue;

                v3s16 nodepos(nodepos2d.X, spawn_level, nodepos2d.Y);
                // Consecutive empty nodes
                s32 air_count = 0;

                // Search upwards from 'spawn level' for 2 consecutive empty nodes, to
                // avoid obstructions in already-generated mapblocks.
                // In ungenerated mapblocks consisting of 'ignore' nodes, there will be
                // no obstructions, but mapgen decorations are generated after spawn so
                // the player may end up inside one.
                for (s32 i = 0; i < 8; i++) {
                        v3s16 blockpos = getNodeBlockPos(nodepos);
                        map.emergeBlock(blockpos, true);
                        content_t c = map.getNode(nodepos).getContent();

                        // In generated mapblocks allow spawn in all 'airlike' drawtype nodes.
                        // In ungenerated mapblocks allow spawn in 'ignore' nodes.
                        if (m_nodedef->get(c).drawtype == NDT_AIRLIKE || c == CONTENT_IGNORE) {
                                air_count++;
                                if (air_count >= 2) {
                                        // Spawn in lower empty node
                                        nodepos.Y--;
                                        nodeposf = intToFloat(nodepos, BS);
                                        // Don't spawn the player outside map boundaries
                                        if (objectpos_over_limit(nodeposf))
                                                // Exit this loop, positions above are probably over limit
                                                break;

                                        // Good position found, cause an exit from main loop
                                        is_good = true;
                                        break;
                                }
                        } else {
                                air_count = 0;
                        }
                        nodepos.Y++;
                }
        }

        if (is_good)
                return nodeposf;

        // No suitable spawn point found, return fallback 0,0,0
        return v3f(0.0f, 0.0f, 0.0f);
}

void Server::requestShutdown(const std::string &msg, bool reconnect, float delay)
{
        if (delay == 0.0f) {
        // No delay, shutdown immediately
                m_shutdown_state.is_requested = true;
                // only print to the infostream, a chat message saying
                // "Server Shutting Down" is sent when the server destructs.
                infostream << "*** Immediate Server shutdown requested." << std::endl;
        } else if (delay < 0.0f && m_shutdown_state.isTimerRunning()) {
                // Negative delay, cancel shutdown if requested
                m_shutdown_state.reset();
                std::wstringstream ws;

                ws << L"*** Server shutdown canceled.";

                infostream << wide_to_utf8(ws.str()).c_str() << std::endl;
                SendChatMessage(PEER_ID_INEXISTENT, ws.str());
                // m_shutdown_* are already handled, skip.
                return;
        } else if (delay > 0.0f) {
        // Positive delay, tell the clients when the server will shut down
                std::wstringstream ws;

                ws << L"*** Server shutting down in "
                                << duration_to_string(myround(delay)).c_str()
                                << ".";

                infostream << wide_to_utf8(ws.str()).c_str() << std::endl;
                SendChatMessage(PEER_ID_INEXISTENT, ws.str());
        }

        m_shutdown_state.trigger(delay, msg, reconnect);
}

PlayerSAO* Server::emergePlayer(const char *name, session_t peer_id, u16 proto_version)
{
        /*
                Try to get an existing player
        */
        RemotePlayer *player = m_env->getPlayer(name);

        // If player is already connected, cancel
        if (player && player->getPeerId() != PEER_ID_INEXISTENT) {
                infostream<<"emergePlayer(): Player already connected"<<std::endl;
                return NULL;
        }

        /*
                If player with the wanted peer_id already exists, cancel.
        */
        if (m_env->getPlayer(peer_id)) {
                infostream<<"emergePlayer(): Player with wrong name but same"
                                " peer_id already exists"<<std::endl;
                return NULL;
        }

        if (!player) {
                player = new RemotePlayer(name, idef());
        }

        bool newplayer = false;

        // Load player
        PlayerSAO *playersao = m_env->loadPlayer(player, &newplayer, peer_id, isSingleplayer());

        // Complete init with server parts
        playersao->finalize(player, getPlayerEffectivePrivs(player->getName()));
        player->protocol_version = proto_version;

        /* Run scripts */
        if (newplayer) {
                m_script->on_newplayer(playersao);
        }

        return playersao;
}

bool Server::registerModStorage(ModMetadata *storage)
{
        if (m_mod_storages.find(storage->getModName()) != m_mod_storages.end()) {
                errorstream << "Unable to register same mod storage twice. Storage name: "
                                << storage->getModName() << std::endl;
                return false;
        }

        m_mod_storages[storage->getModName()] = storage;
        return true;
}

void Server::unregisterModStorage(const std::string &name)
{
        std::unordered_map<std::string, ModMetadata *>::const_iterator it = m_mod_storages.find(name);
        if (it != m_mod_storages.end()) {
                // Save unconditionaly on unregistration
                it->second->save(getModStoragePath());
                m_mod_storages.erase(name);
        }
}

void dedicated_server_loop(Server &server, bool &kill)
{
        verbosestream<<"dedicated_server_loop()"<<std::endl;

        IntervalLimiter m_profiler_interval;

        static thread_local const float steplen =
                        g_settings->getFloat("dedicated_server_step");
        static thread_local const float profiler_print_interval =
                        g_settings->getFloat("profiler_print_interval");

        /*
         * The dedicated server loop only does time-keeping (in Server::step) and
         * provides a way to main.cpp to kill the server externally (bool &kill).
         */

        for(;;) {
                // This is kind of a hack but can be done like this
                // because server.step() is very light
                sleep_ms((int)(steplen*1000.0));
                server.step(steplen);

                if (server.isShutdownRequested() || kill)
                        break;

                /*
                        Profiler
                */
                if (profiler_print_interval != 0) {
                        if(m_profiler_interval.step(steplen, profiler_print_interval))
                        {
                                infostream<<"Profiler:"<<std::endl;
                                g_profiler->print(infostream);
                                g_profiler->clear();
                        }
                }
        }

        infostream << "Dedicated server quitting" << std::endl;
#if USE_CURL
        if (g_settings->getBool("server_announce"))
                ServerList::sendAnnounce(ServerList::AA_DELETE,
                        server.m_bind_addr.getPort());
#endif
}

/*
 * Mod channels
 */


bool Server::joinModChannel(const std::string &channel)
{
        return m_modchannel_mgr->joinChannel(channel, PEER_ID_SERVER) &&
                        m_modchannel_mgr->setChannelState(channel, MODCHANNEL_STATE_READ_WRITE);
}

bool Server::leaveModChannel(const std::string &channel)
{
        return m_modchannel_mgr->leaveChannel(channel, PEER_ID_SERVER);
}

bool Server::sendModChannelMessage(const std::string &channel, const std::string &message)
{
        if (!m_modchannel_mgr->canWriteOnChannel(channel))
                return false;

        broadcastModChannelMessage(channel, message, PEER_ID_SERVER);
        return true;
}

ModChannel* Server::getModChannel(const std::string &channel)
{
        return m_modchannel_mgr->getModChannel(channel);
}

void Server::broadcastModChannelMessage(const std::string &channel,
                const std::string &message, session_t from_peer)
{
        const std::vector<u16> &peers = m_modchannel_mgr->getChannelPeers(channel);
        if (peers.empty())
                return;

        if (message.size() > STRING_MAX_LEN) {
                warningstream << "ModChannel message too long, dropping before sending "
                                << " (" << message.size() << " > " << STRING_MAX_LEN << ", channel: "
                                << channel << ")" << std::endl;
                return;
        }

        std::string sender;
        if (from_peer != PEER_ID_SERVER) {
                sender = getPlayerName(from_peer);
        }

        NetworkPacket resp_pkt(TOCLIENT_MODCHANNEL_MSG,
                        2 + channel.size() + 2 + sender.size() + 2 + message.size());
        resp_pkt << channel << sender << message;
        for (session_t peer_id : peers) {
                // Ignore sender
                if (peer_id == from_peer)
                        continue;

                Send(peer_id, &resp_pkt);
        }

        if (from_peer != PEER_ID_SERVER) {
                m_script->on_modchannel_message(channel, sender, message);
        }
}

Translations *Server::getTranslationLanguage(const std::string &lang_code)
{
        if (lang_code.empty())
                return nullptr;

        auto it = server_translations.find(lang_code);
        if (it != server_translations.end())
                return &it->second; // Already loaded

        // [] will create an entry
        auto *translations = &server_translations[lang_code];

        std::string suffix = "." + lang_code + ".tr";
        for (const auto &i : m_media) {
                if (str_ends_with(i.first, suffix)) {
                        std::string data;
                        if (fs::ReadFile(i.second.path, data)) {
                                translations->loadTranslation(data);
                        }
                }
        }

        return translations;
}