/* Copyright (C) 2019 Mr Goldberg
   This file is part of the Goldberg Emulator

   The Goldberg Emulator 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 3 of the License, or (at your option) any later version.

   The Goldberg Emulator 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 the Goldberg Emulator; if not, see
   <http://www.gnu.org/licenses/>.  */

#include "base.h"

//packet timeout in seconds for non connections
#define ORPHANED_PACKET_TIMEOUT (20)
#define NEW_CONNECTION_TIMEOUT (20.0)

//kingdom 2 crowns doesn't work with a 0.3 delay or lower
#define NEW_CONNECTION_DELAY (0.4)

#define OLD_CHANNEL_NUMBER 1

struct Steam_Networking_Connection {
    CSteamID remote;
    std::set<int> open_channels;
};

struct steam_listen_socket {
    SNetListenSocket_t id;
    int nVirtualP2PPort;
    uint32 nIP;
    uint16 nPort;
};

enum steam_socket_connection_status {
    SOCKET_CONNECTING,
    SOCKET_CONNECTED,
    SOCKET_DISCONNECTED,
    SOCKET_KILLED,
};

struct steam_connection_socket {
    SNetSocket_t id;
    SNetListenSocket_t listen_id;
    enum steam_socket_connection_status status;
    CSteamID target;
    int nVirtualPort;
    uint32 nIP;
    uint16 nPort;
    SNetSocket_t other_id;
    std::vector<Network_Old> data_packets;
};

class Steam_Networking :
public ISteamNetworking001,
public ISteamNetworking002,
public ISteamNetworking003,
public ISteamNetworking004,
public ISteamNetworking005,
public ISteamNetworking
{
    class Settings *settings;
    class Networking *network;

    class SteamCallBacks *callbacks;
    class RunEveryRunCB *run_every_runcb;

    std::recursive_mutex messages_mutex;
    std::list<Common_Message> messages;
    std::list<Common_Message> unprocessed_messages;

    std::recursive_mutex connections_edit_mutex;
    std::vector<struct Steam_Networking_Connection> connections;

    std::vector<struct steam_listen_socket> listen_sockets;
    std::vector<struct steam_connection_socket> connection_sockets;

    std::map<CSteamID, std::chrono::high_resolution_clock::time_point> new_connection_times;
    std::queue<CSteamID> new_connections_to_call_cb;

bool connection_exists(CSteamID id)
{
    std::lock_guard<std::recursive_mutex> lock(connections_edit_mutex);
    return std::find_if(connections.begin(), connections.end(), [&id](struct Steam_Networking_Connection const& conn) { return conn.remote == id;}) != connections.end();
}

struct Steam_Networking_Connection *get_or_create_connection(CSteamID id)
{
    std::lock_guard<std::recursive_mutex> lock(connections_edit_mutex);
    auto conn = std::find_if(connections.begin(), connections.end(), [&id](struct Steam_Networking_Connection const& conn) { return conn.remote == id;});

    if (connections.end() == conn) {
        struct Steam_Networking_Connection connection;
        connection.remote = id;
        connections.push_back(connection);
        return &(connections[connections.size() - 1]);
    } else {
        return &(*conn);
    }
}

void remove_connection(CSteamID id)
{
    {
        std::lock_guard<std::recursive_mutex> lock(connections_edit_mutex);
        auto conn = std::begin(connections);
        while (conn != std::end(connections)) {
            if (conn->remote == id) {

                conn = connections.erase(conn);
            } else {
                ++conn;
            }
        }
    }

    //pretty sure steam also clears the entire queue of messages for that connection
    {
        std::lock_guard<std::recursive_mutex> lock(messages_mutex);
        auto msg = std::begin(messages);
        while (msg != std::end(messages)) {
            if (msg->source_id() == id.ConvertToUint64()) {
                msg = messages.erase(msg);
            } else {
                ++msg;
            }
        }
    }

    {
        auto msg = std::begin(unprocessed_messages);
        while (msg != std::end(unprocessed_messages)) {
            if (msg->source_id() == id.ConvertToUint64()) {
                msg = unprocessed_messages.erase(msg);
            } else {
                ++msg;
            }
        }
    }
}

SNetSocket_t create_connection_socket(CSteamID target, int nVirtualPort, uint32 nIP, uint16 nPort, SNetListenSocket_t id=0, enum steam_socket_connection_status status=SOCKET_CONNECTING, SNetSocket_t other_id=0)
{
    static SNetSocket_t socket_number = 0;
    bool found;
    do {
        found = false;
        ++socket_number;
        for (auto & c: connection_sockets) {
            if (c.id == socket_number || socket_number == 0) {
                found = true;
                break;
            }
        }
    } while (found);

    struct steam_connection_socket socket;
    socket.id = socket_number;
    socket.listen_id = id;
    socket.status = status;
    socket.target = target;
    socket.nVirtualPort = nVirtualPort;
    socket.nIP = nIP;
    socket.nPort = nPort;
    socket.other_id = other_id;
    connection_sockets.push_back(socket);

    Common_Message msg;
    msg.set_source_id(settings->get_local_steam_id().ConvertToUint64());
    msg.set_dest_id(target.ConvertToUint64());
    msg.set_allocated_network_old(new Network_Old);
    if (nPort) {
        msg.mutable_network_old()->set_type(Network_Old::CONNECTION_REQUEST_IP);
        msg.mutable_network_old()->set_port(nPort);
    } else {
        msg.mutable_network_old()->set_type(Network_Old::CONNECTION_REQUEST_STEAMID);
        msg.mutable_network_old()->set_port(nVirtualPort);
    }

    if (socket.status == SOCKET_CONNECTED) {
        msg.mutable_network_old()->set_type(Network_Old::CONNECTION_ACCEPTED);
    }

    msg.mutable_network_old()->set_connection_id(socket.other_id);
    msg.mutable_network_old()->set_connection_id_from(socket.id);

    if (target.IsValid()) {
        network->sendTo(&msg, true);
    } else if (nIP) {
        network->sendToIPPort(&msg, nIP, nPort, true);
    }

    return socket.id;
}

struct steam_connection_socket *get_connection_socket(SNetSocket_t id)
{
    auto conn = std::find_if(connection_sockets.begin(), connection_sockets.end(), [&id](struct steam_connection_socket const& conn) { return conn.id == id;});
    if (conn == connection_sockets.end()) return NULL;
    return &(*conn);
}

void remove_killed_connection_sockets()
{
    auto socket = std::begin(connection_sockets);
    while (socket != std::end(connection_sockets)) {
        if (socket->status == SOCKET_KILLED || socket->status == SOCKET_DISCONNECTED) {
            socket = connection_sockets.erase(socket);
        } else {
            ++socket;
        }
    }
}

public:
static void steam_networking_callback(void *object, Common_Message *msg)
{
    // PRINT_DEBUG_ENTRY();

    Steam_Networking *steam_networking = (Steam_Networking *)object;
    steam_networking->Callback(msg);
}

static void steam_networking_run_every_runcp(void *object)
{
    // PRINT_DEBUG_ENTRY();

    Steam_Networking *steam_networking = (Steam_Networking *)object;
    steam_networking->RunCallbacks();
}

Steam_Networking(class Settings *settings, class Networking *network, class SteamCallBacks *callbacks, class RunEveryRunCB *run_every_runcb)
{
    this->settings = settings;
    this->network = network;
    this->run_every_runcb = run_every_runcb;
    this->network->setCallback(CALLBACK_ID_NETWORKING, settings->get_local_steam_id(), &Steam_Networking::steam_networking_callback, this);
    this->network->setCallback(CALLBACK_ID_USER_STATUS, settings->get_local_steam_id(), &Steam_Networking::steam_networking_callback, this);
    this->run_every_runcb->add(&Steam_Networking::steam_networking_run_every_runcp, this);

    this->callbacks = callbacks;

    PRINT_DEBUG("steam_networking_contructor %llu messages: %p", settings->get_local_steam_id().ConvertToUint64(), &messages);
}

~Steam_Networking()
{
    this->network->rmCallback(CALLBACK_ID_NETWORKING, settings->get_local_steam_id(), &Steam_Networking::steam_networking_callback, this);
    this->network->rmCallback(CALLBACK_ID_USER_STATUS, settings->get_local_steam_id(), &Steam_Networking::steam_networking_callback, this);
    this->run_every_runcb->remove(&Steam_Networking::steam_networking_run_every_runcp, this);
}

////////////////////////////////////////////////////////////////////////////////////////////
// Session-less connection functions
//    automatically establishes NAT-traversing or Relay server connections

// Sends a P2P packet to the specified user
// UDP-like, unreliable and a max packet size of 1200 bytes
// the first packet send may be delayed as the NAT-traversal code runs
// if we can't get through to the user, an error will be posted via the callback P2PSessionConnectFail_t
// see EP2PSend enum above for the descriptions of the different ways of sending packets
//
// nChannel is a routing number you can use to help route message to different systems 	- you'll have to call ReadP2PPacket() 
// with the same channel number in order to retrieve the data on the other end
// using different channels to talk to the same user will still use the same underlying p2p connection, saving on resources
bool SendP2PPacket( CSteamID steamIDRemote, const void *pubData, uint32 cubData, EP2PSend eP2PSendType, int nChannel)
{
    PRINT_DEBUG("len %u sendtype: %u channel: %u to: %llu", cubData, eP2PSendType, nChannel, steamIDRemote.ConvertToUint64());
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    bool reliable = false;
    if (eP2PSendType == k_EP2PSendReliable || eP2PSendType == k_EP2PSendReliableWithBuffering) reliable = true;
    Common_Message msg;
    msg.set_source_id(settings->get_local_steam_id().ConvertToUint64());
    msg.set_dest_id(steamIDRemote.ConvertToUint64());
    msg.set_allocated_network(new Network_pb);

    if (!connection_exists(steamIDRemote)) {
        msg.mutable_network()->set_type(Network_pb::NEW_CONNECTION);
        network->sendTo(&msg, true);
    }

    msg.mutable_network()->set_channel(nChannel);
    msg.mutable_network()->set_data(pubData, cubData);
    msg.mutable_network()->set_type(Network_pb::DATA);

    struct Steam_Networking_Connection *conn = get_or_create_connection(steamIDRemote);
    new_connection_times.erase(steamIDRemote);

    conn->open_channels.insert(nChannel);
    bool ret = network->sendTo(&msg, reliable);
    PRINT_DEBUG("Sent message with size: %zu %u", msg.network().data().size(), ret);
    return ret;
}

bool SendP2PPacket( CSteamID steamIDRemote, const void *pubData, uint32 cubData, EP2PSend eP2PSendType ) {
    PRINT_DEBUG("old");
    return SendP2PPacket(steamIDRemote, pubData, cubData, eP2PSendType, OLD_CHANNEL_NUMBER);
}

// returns true if any data is available for read, and the amount of data that will need to be read
bool IsP2PPacketAvailable( uint32 *pcubMsgSize, int nChannel)
{
    PRINT_DEBUG("channel: %i", nChannel);
    std::lock_guard<std::recursive_mutex> lock(messages_mutex);
    //Not sure if this should be here because it slightly screws up games that don't like such low "pings"
    //Commenting it out for now because it looks like it causes a bug where 20xx gets stuck in an infinite receive packet loop
    //this->network->Run();
    //RunCallbacks();

    PRINT_DEBUG("Messages %zu %p", messages.size(), &messages);
    for (auto &msg : messages) {
        if (connection_exists((uint64)msg.source_id()) && msg.mutable_network()->channel() == nChannel && msg.network().processed()) {
            uint32 size = msg.mutable_network()->data().size();
            if (pcubMsgSize) *pcubMsgSize = size;
            PRINT_DEBUG("available with size: %u", size);
            return true;
        }
    }

    PRINT_DEBUG("(not available)");
    if (pcubMsgSize) *pcubMsgSize = 0;
    return false;
}

bool IsP2PPacketAvailable( uint32 *pcubMsgSize)
{
    PRINT_DEBUG("old");
    return IsP2PPacketAvailable(pcubMsgSize, OLD_CHANNEL_NUMBER);
}

// reads in a packet that has been sent from another user via SendP2PPacket()
// returns the size of the message and the steamID of the user who sent it in the last two parameters
// if the buffer passed in is too small, the message will be truncated
// this call is not blocking, and will return false if no data is available
bool ReadP2PPacket( void *pubDest, uint32 cubDest, uint32 *pcubMsgSize, CSteamID *psteamIDRemote, int nChannel)
{
    PRINT_DEBUG("%u %i", cubDest, nChannel);
    std::lock_guard<std::recursive_mutex> lock(messages_mutex);
    //Not sure if this should be here because it slightly screws up games that don't like such low "pings"
    //Commenting it out for now because it looks like it causes a bug where 20xx gets stuck in an infinite receive packet loop
    //this->network->Run();
    //RunCallbacks();

    bool read = false;
    PRINT_DEBUG("Number messages %zu", messages.size());
    auto msg = std::begin(messages);
    while (msg != std::end(messages)) {
        if (connection_exists((uint64)msg->source_id()) && msg->network().channel() == nChannel && msg->network().processed()) {
            uint32 msg_size = msg->network().data().size();
            if (msg_size > cubDest) msg_size = cubDest;
            if (pcubMsgSize) *pcubMsgSize = msg_size;
            memcpy(pubDest, msg->network().data().data(), msg_size);

            PRINT_DEBUG("%s",
                common_helpers::uint8_vector_to_hex_string(std::vector<uint8_t>((uint8_t*)pubDest, (uint8_t*)pubDest + msg_size)).c_str());
            
            *psteamIDRemote = CSteamID((uint64)msg->source_id());
            PRINT_DEBUG("len %u channel: %u from: " "%" PRIu64 "", msg_size, nChannel, msg->source_id());
            msg = messages.erase(msg);
            return true;
        }

        ++msg;
    }

    if (pcubMsgSize) *pcubMsgSize = 0;
    if (psteamIDRemote) *psteamIDRemote = k_steamIDNil;
    return false;
}

bool ReadP2PPacket( void *pubDest, uint32 cubDest, uint32 *pcubMsgSize, CSteamID *psteamIDRemote)
{
    PRINT_DEBUG("old");
    return ReadP2PPacket(pubDest, cubDest, pcubMsgSize, psteamIDRemote, OLD_CHANNEL_NUMBER);
}

// AcceptP2PSessionWithUser() should only be called in response to a P2PSessionRequest_t callback
// P2PSessionRequest_t will be posted if another user tries to send you a packet that you haven't talked to yet
// if you don't want to talk to the user, just ignore the request
// if the user continues to send you packets, another P2PSessionRequest_t will be posted periodically
// this may be called multiple times for a single user
// (if you've called SendP2PPacket() on the other user, this implicitly accepts the session request)
bool AcceptP2PSessionWithUser( CSteamID steamIDRemote )
{
    PRINT_DEBUG("%llu", steamIDRemote.ConvertToUint64());
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    struct Steam_Networking_Connection *conn = get_or_create_connection(steamIDRemote);
    if (conn) new_connection_times.erase(steamIDRemote);
    return !!conn;
}


// call CloseP2PSessionWithUser() when you're done talking to a user, will free up resources under-the-hood
// if the remote user tries to send data to you again, another P2PSessionRequest_t callback will be posted
bool CloseP2PSessionWithUser( CSteamID steamIDRemote )
{
    PRINT_DEBUG("%llu", steamIDRemote.ConvertToUint64());
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    if (!connection_exists(steamIDRemote)) {
        
        return false;
    }

    remove_connection(steamIDRemote);
    
    return true;
}


// call CloseP2PChannelWithUser() when you're done talking to a user on a specific channel. Once all channels
// open channels to a user have been closed, the open session to the user will be closed and new data from this
// user will trigger a P2PSessionRequest_t callback
bool CloseP2PChannelWithUser( CSteamID steamIDRemote, int nChannel )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    if (!connection_exists(steamIDRemote)) {
        return false;
    }

    struct Steam_Networking_Connection *conn = get_or_create_connection(steamIDRemote);

    conn->open_channels.erase(nChannel);
    if (conn->open_channels.size() == 0) {
        remove_connection(steamIDRemote);
    }

    return true;
}


// fills out P2PSessionState_t structure with details about the underlying connection to the user
// should only needed for debugging purposes
// returns false if no connection exists to the specified user
bool GetP2PSessionState( CSteamID steamIDRemote, P2PSessionState_t *pConnectionState )
{
    PRINT_DEBUG("%llu", steamIDRemote.ConvertToUint64());
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    if (!connection_exists(steamIDRemote) && (steamIDRemote != settings->get_local_steam_id())) {
        if (pConnectionState) {
            pConnectionState->m_bConnectionActive = false;
            pConnectionState->m_bConnecting = false;
            pConnectionState->m_eP2PSessionError = 0;
            pConnectionState->m_bUsingRelay = false;
            pConnectionState->m_nBytesQueuedForSend = 0;
            pConnectionState->m_nPacketsQueuedForSend = 0;
            pConnectionState->m_nRemoteIP = 0;
            pConnectionState->m_nRemotePort = 0;
        }

        PRINT_DEBUG("No Connection");
        return false;
    }

    if (pConnectionState) {
        pConnectionState->m_bConnectionActive = true;
        pConnectionState->m_bConnecting = false;
        pConnectionState->m_eP2PSessionError = 0;
        pConnectionState->m_bUsingRelay = false;
        pConnectionState->m_nBytesQueuedForSend = 0;
        pConnectionState->m_nPacketsQueuedForSend = 0;
        pConnectionState->m_nRemoteIP = network->getIP(steamIDRemote);
        pConnectionState->m_nRemotePort = 12345;
    }

    PRINT_DEBUG("Connection");
    return true;
}


// Allow P2P connections to fall back to being relayed through the Steam servers if a direct connection
// or NAT-traversal cannot be established. Only applies to connections created after setting this value,
// or to existing connections that need to automatically reconnect after this value is set.
//
// P2P packet relay is allowed by default
bool AllowP2PPacketRelay( bool bAllow )
{
    PRINT_DEBUG("%u", bAllow);
    return true;
}



////////////////////////////////////////////////////////////////////////////////////////////
// LISTEN / CONNECT style interface functions
//
// This is an older set of functions designed around the Berkeley TCP sockets model
// it's preferential that you use the above P2P functions, they're more robust
// and these older functions will be removed eventually
//
////////////////////////////////////////////////////////////////////////////////////////////

SNetListenSocket_t socket_number = 0;
// creates a socket and listens others to connect
// will trigger a SocketStatusCallback_t callback on another client connecting
// nVirtualP2PPort is the unique ID that the client will connect to, in case you have multiple ports
//		this can usually just be 0 unless you want multiple sets of connections
// unIP is the local IP address to bind to
//		pass in 0 if you just want the default local IP
// unPort is the port to use
//		pass in 0 if you don't want users to be able to connect via IP/Port, but expect to be always peer-to-peer connections only
SNetListenSocket_t CreateListenSocket( int nVirtualP2PPort, uint32 nIP, uint16 nPort, bool bAllowUseOfPacketRelay )
{
    PRINT_DEBUG("old %i %u %hu %u", nVirtualP2PPort, nIP, nPort, bAllowUseOfPacketRelay);
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    for (auto & c : listen_sockets) {
        if (c.nVirtualP2PPort == nVirtualP2PPort || c.nPort == nPort)
            return 0;
    }

    ++socket_number;
    if (!socket_number) ++socket_number;

    struct steam_listen_socket socket;
    socket.id = socket_number;
    socket.nVirtualP2PPort = nVirtualP2PPort;
    socket.nIP = nIP;
    socket.nPort = nPort;
    listen_sockets.push_back(socket);
    return socket.id;
}

SNetListenSocket_t CreateListenSocket( int nVirtualP2PPort, SteamIPAddress_t nIP, uint16 nPort, bool bAllowUseOfPacketRelay )
{
    PRINT_DEBUG("%i %i %u %hu %u", nVirtualP2PPort, nIP.m_eType, nIP.m_unIPv4, nPort, bAllowUseOfPacketRelay);
    //TODO: ipv6
    return CreateListenSocket(nVirtualP2PPort, nIP.m_unIPv4, nPort, bAllowUseOfPacketRelay);
}

SNetListenSocket_t CreateListenSocket( int nVirtualP2PPort, uint32 nIP, uint16 nPort )
{
    PRINT_DEBUG("old");
    return CreateListenSocket(nVirtualP2PPort, nIP, nPort, true);
}

// creates a socket and begin connection to a remote destination
// can connect via a known steamID (client or game server), or directly to an IP
// on success will trigger a SocketStatusCallback_t callback
// on failure or timeout will trigger a SocketStatusCallback_t callback with a failure code in m_eSNetSocketState
SNetSocket_t CreateP2PConnectionSocket( CSteamID steamIDTarget, int nVirtualPort, int nTimeoutSec, bool bAllowUseOfPacketRelay )
{
    PRINT_DEBUG("%llu %i %i %u", steamIDTarget.ConvertToUint64(), nVirtualPort, nTimeoutSec, bAllowUseOfPacketRelay);
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    //TODO: nTimeoutSec
    return create_connection_socket(steamIDTarget, nVirtualPort, 0, 0);
}

SNetSocket_t CreateP2PConnectionSocket( CSteamID steamIDTarget, int nVirtualPort, int nTimeoutSec )
{
    PRINT_DEBUG("old");
    return CreateP2PConnectionSocket(steamIDTarget, nVirtualPort, nTimeoutSec, true);
}

SNetSocket_t CreateConnectionSocket( uint32 nIP, uint16 nPort, int nTimeoutSec )
{
    PRINT_DEBUG("%u %hu %i", nIP, nPort, nTimeoutSec);
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    //TODO: nTimeoutSec
    return create_connection_socket((uint64)0, 0, nIP, nPort);
}

SNetSocket_t CreateConnectionSocket( SteamIPAddress_t nIP, uint16 nPort, int nTimeoutSec )
{
    PRINT_DEBUG("%i %u %hu %i", nIP.m_eType, nIP.m_unIPv4, nPort, nTimeoutSec);
    //TODO: ipv6
    return CreateConnectionSocket(nIP.m_unIPv4, nPort, nTimeoutSec);
}

// disconnects the connection to the socket, if any, and invalidates the handle
// any unread data on the socket will be thrown away
// if bNotifyRemoteEnd is set, socket will not be completely destroyed until the remote end acknowledges the disconnect
bool DestroySocket( SNetSocket_t hSocket, bool bNotifyRemoteEnd )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    struct steam_connection_socket *socket = get_connection_socket(hSocket);
    if (!socket || socket->status == SOCKET_KILLED) return false;
    socket->status = SOCKET_KILLED;
    return true;
}

// destroying a listen socket will automatically kill all the regular sockets generated from it
bool DestroyListenSocket( SNetListenSocket_t hSocket, bool bNotifyRemoteEnd )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    auto c = std::begin(listen_sockets);
    while (c != std::end(listen_sockets)) {
        if (c->id == hSocket) {
            c = listen_sockets.erase(c);
            for (auto & socket : connection_sockets) {
                if (socket.listen_id == hSocket) {
                    socket.status = SOCKET_KILLED;
                }
            }
            return true;
        } else {
            ++c;
        }
    }

    return false;
}


// sending data
// must be a handle to a connected socket
// data is all sent via UDP, and thus send sizes are limited to 1200 bytes; after this, many routers will start dropping packets
// use the reliable flag with caution; although the resend rate is pretty aggressive,
// it can still cause stalls in receiving data (like TCP)
bool SendDataOnSocket( SNetSocket_t hSocket, void *pubData, uint32 cubData, bool bReliable )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    struct steam_connection_socket *socket = get_connection_socket(hSocket);
    if (!socket || socket->status != SOCKET_CONNECTED) return false;

    Common_Message msg;
    msg.set_source_id(settings->get_local_steam_id().ConvertToUint64());
    msg.set_dest_id(socket->target.ConvertToUint64());
    msg.set_allocated_network_old(new Network_Old);
    msg.mutable_network_old()->set_type(Network_Old::DATA);
    msg.mutable_network_old()->set_connection_id(socket->other_id);
    msg.mutable_network_old()->set_data(pubData, cubData);
    return network->sendTo(&msg, bReliable);
}


// receiving data
// returns false if there is no data remaining
// fills out *pcubMsgSize with the size of the next message, in bytes
bool IsDataAvailableOnSocket( SNetSocket_t hSocket, uint32 *pcubMsgSize )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    struct steam_connection_socket *socket = get_connection_socket(hSocket);
    if (!socket) {
        if (pcubMsgSize) *pcubMsgSize = 0;
        return false;
    }

    if (socket->data_packets.size() == 0) return false;
    if (pcubMsgSize) *pcubMsgSize = socket->data_packets[0].data().size();
    return true;
}


// fills in pubDest with the contents of the message
// messages are always complete, of the same size as was sent (i.e. packetized, not streaming)
// if *pcubMsgSize < cubDest, only partial data is written
// returns false if no data is available
bool RetrieveDataFromSocket( SNetSocket_t hSocket, void *pubDest, uint32 cubDest, uint32 *pcubMsgSize )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    struct steam_connection_socket *socket = get_connection_socket(hSocket);
    if (!socket || socket->data_packets.size() == 0) return false;

    auto msg = std::begin(socket->data_packets);
    if (msg != std::end(socket->data_packets)) {
        uint32 msg_size = msg->data().size();
        if (msg_size > cubDest) msg_size = cubDest;
        if (pcubMsgSize) *pcubMsgSize = msg_size;
        memcpy(pubDest, msg->data().data(), msg_size);
        msg = socket->data_packets.erase(msg);
        return true;
    }

    return false;
}


// checks for data from any socket that has been connected off this listen socket
// returns false if there is no data remaining
// fills out *pcubMsgSize with the size of the next message, in bytes
// fills out *phSocket with the socket that data is available on
bool IsDataAvailable( SNetListenSocket_t hListenSocket, uint32 *pcubMsgSize, SNetSocket_t *phSocket )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    if (!hListenSocket) return false;

    for (auto & socket : connection_sockets) {
        if (socket.listen_id == hListenSocket && socket.data_packets.size()) {
            if (pcubMsgSize) *pcubMsgSize = socket.data_packets[0].data().size();
            if (phSocket) *phSocket = socket.id;
            return true;
        }
    }

    return false;
}


// retrieves data from any socket that has been connected off this listen socket
// fills in pubDest with the contents of the message
// messages are always complete, of the same size as was sent (i.e. packetized, not streaming)
// if *pcubMsgSize < cubDest, only partial data is written
// returns false if no data is available
// fills out *phSocket with the socket that data is available on
bool RetrieveData( SNetListenSocket_t hListenSocket, void *pubDest, uint32 cubDest, uint32 *pcubMsgSize, SNetSocket_t *phSocket )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    if (!hListenSocket) return false;

    for (auto & socket : connection_sockets) {
        if (socket.listen_id == hListenSocket && socket.data_packets.size()) {
            auto msg = std::begin(socket.data_packets);
            if (msg != std::end(socket.data_packets)) {
                uint32 msg_size = msg->data().size();
                if (msg_size > cubDest) msg_size = cubDest;
                if (pcubMsgSize) *pcubMsgSize = msg_size;
                if (phSocket) *phSocket = socket.id;
                memcpy(pubDest, msg->data().data(), msg_size);
                msg = socket.data_packets.erase(msg);
                return true;
            }
        }
    }

    return false;
}


// returns information about the specified socket, filling out the contents of the pointers
bool GetSocketInfo( SNetSocket_t hSocket, CSteamID *pSteamIDRemote, int *peSocketStatus, uint32 *punIPRemote, uint16 *punPortRemote )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    struct steam_connection_socket *socket = get_connection_socket(hSocket);
    if (!socket) return false;
    if (pSteamIDRemote) *pSteamIDRemote = socket->target;
    if (peSocketStatus) {
        //TODO: I'm not sure what peSocketStatus is supposed to be but I'm guessing it's ESNetSocketState
        if (socket->status == SOCKET_CONNECTED) {
            *peSocketStatus = k_ESNetSocketStateConnected;
        } else if (socket->status == SOCKET_CONNECTING) {
            *peSocketStatus = k_ESNetSocketStateInitiated;
        } else if (socket->status == SOCKET_DISCONNECTED) {
            *peSocketStatus = k_ESNetSocketStateDisconnecting;
        } else if (socket->status == SOCKET_KILLED) {
            *peSocketStatus = k_ESNetSocketStateConnectionBroken;
        } else {
            *peSocketStatus = k_ESNetSocketStateInvalid;
        }
    }

    if (punIPRemote) *punIPRemote = socket->nIP;
    if (punPortRemote) *punPortRemote = socket->nPort;
    return true;
}

bool GetSocketInfo( SNetSocket_t hSocket, CSteamID *pSteamIDRemote, int *peSocketStatus, SteamIPAddress_t *punIPRemote, uint16 *punPortRemote )
{
    PRINT_DEBUG_ENTRY();
    //TODO: ipv6
    uint32 *ip_remote = NULL;
    if (punIPRemote) {
        ip_remote = &(punIPRemote->m_unIPv4);
    }

    bool ret = GetSocketInfo(hSocket, pSteamIDRemote, peSocketStatus, ip_remote, punPortRemote );
    if (punIPRemote && ret) {
        punIPRemote->m_eType = k_ESteamIPTypeIPv4;
    }

    return ret;
}

// returns which local port the listen socket is bound to
// *pnIP and *pnPort will be 0 if the socket is set to listen for P2P connections only
bool GetListenSocketInfo( SNetListenSocket_t hListenSocket, uint32 *pnIP, uint16 *pnPort )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    auto conn = std::find_if(listen_sockets.begin(), listen_sockets.end(), [&hListenSocket](struct steam_listen_socket const& conn) { return conn.id == hListenSocket;});
    if (conn == listen_sockets.end()) return false;
    if (pnIP) *pnIP = conn->nIP;
    if (pnPort) *pnPort = conn->nPort;
    return true;
}

bool GetListenSocketInfo( SNetListenSocket_t hListenSocket, SteamIPAddress_t *pnIP, uint16 *pnPort )
{
    PRINT_DEBUG_ENTRY();
    //TODO: ipv6
    uint32 *ip = NULL;
    if (pnIP) {
        ip = &(pnIP->m_unIPv4);
    }

    bool ret = GetListenSocketInfo(hListenSocket, ip, pnPort );
    if (pnIP && ret) {
        pnIP->m_eType = k_ESteamIPTypeIPv4;
    }

    return ret;
}

// returns true to describe how the socket ended up connecting
ESNetSocketConnectionType GetSocketConnectionType( SNetSocket_t hSocket )
{
    PRINT_DEBUG_ENTRY();
    std::lock_guard<std::recursive_mutex> lock(global_mutex);
    struct steam_connection_socket *socket = get_connection_socket(hSocket);
    if (!socket || socket->status != SOCKET_CONNECTED) return k_ESNetSocketConnectionTypeNotConnected;
    else return k_ESNetSocketConnectionTypeUDP;
}


// max packet size, in bytes
int GetMaxPacketSize( SNetSocket_t hSocket )
{
    PRINT_DEBUG_ENTRY();
    return 1500;
}

void RunCallbacks()
{
    uint64 current_time = std::chrono::duration_cast<std::chrono::duration<uint64>>(std::chrono::system_clock::now().time_since_epoch()).count();

    {
    std::lock_guard<std::recursive_mutex> lock(messages_mutex);

    {
        auto msg = std::begin(unprocessed_messages);
        while (msg != std::end(unprocessed_messages)) {
            CSteamID source_id((uint64)msg->source_id());
            if (!connection_exists(source_id)) {
                if (new_connection_times.find(source_id) == new_connection_times.end()) {
                    new_connections_to_call_cb.push(source_id);
                    new_connection_times[source_id] = std::chrono::high_resolution_clock::now();
                }
            } else {
                struct Steam_Networking_Connection *conn = get_or_create_connection(source_id);
                conn->open_channels.insert(msg->network().channel());
            }

            msg->mutable_network()->set_processed(true);
            msg->mutable_network()->set_time_processed(current_time);
            messages.push_back(*msg);
            msg = unprocessed_messages.erase(msg);
        }
    }

    auto msg = std::begin(messages);
    while (msg != std::end(messages)) {
        bool deleted = false;
        if (msg->network().processed()) {
            if (!connection_exists((uint64)msg->source_id())) {
                if (msg->network().time_processed() + ORPHANED_PACKET_TIMEOUT < current_time) {
                    deleted = true;
                }
            }
        }

        if (deleted) {
            msg = messages.erase(msg);
        } else {
            ++msg;
        }
    }

    }

    while (!new_connections_to_call_cb.empty()) {
        CSteamID source_id = new_connections_to_call_cb.front();
        auto t = new_connection_times.find(source_id);
        if (t == new_connection_times.end()) {
            new_connections_to_call_cb.pop();
            continue;
        }

        if (!check_timedout(t->second, NEW_CONNECTION_DELAY)) {
            break;
        }

        P2PSessionRequest_t data;
        memset(&data, 0, sizeof(data));
        data.m_steamIDRemote = source_id;
        callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
        new_connections_to_call_cb.pop();
    }

    //TODO: not sure if sockets should be wiped right away
    remove_killed_connection_sockets();

    for(auto it = new_connection_times.begin(); it != new_connection_times.end(); ) {
        if (std::chrono::duration_cast<std::chrono::duration<double>>(std::chrono::high_resolution_clock::now() - it->second).count() > NEW_CONNECTION_TIMEOUT) {
            it = new_connection_times.erase(it);
            //TODO send packet to other side to tell them connection has "failed".
        } else {
            ++it;
        }
    }
}

void Callback(Common_Message *msg)
{
    if (msg->has_network()) {
        PRINT_DEBUG("got msg from: " "%" PRIu64 " to: " "%" PRIu64 " size %zu type %u | messages %p: %zu",
            msg->source_id(), msg->dest_id(), msg->network().data().size(), msg->network().type(), &messages, messages.size()
        );
        PRINT_DEBUG("msg data: '%s'",
            common_helpers::uint8_vector_to_hex_string(std::vector<uint8_t>(msg->network().data().begin(), msg->network().data().end())).c_str());

        if (msg->network().type() == Network_pb::DATA) {
            unprocessed_messages.push_back(Common_Message(*msg));
        }

        if (msg->network().type() == Network_pb::NEW_CONNECTION) {
            std::lock_guard<std::recursive_mutex> lock(messages_mutex);
            auto msg_temp = std::begin(messages);
            while (msg_temp != std::end(messages)) {
                //only delete processed to handle unreliable message arriving at the same time.
                if (msg_temp->source_id() == msg->source_id() && msg_temp->network().processed()) {
                    msg_temp = messages.erase(msg_temp);
                } else {
                    ++msg_temp;
                }
            }
        }
    }

    if (msg->has_network_old()) {
        PRINT_DEBUG("got network socket msg %u", msg->network_old().type());
        if (msg->network_old().type() == Network_Old::CONNECTION_REQUEST_IP) {
            for (auto & listen : listen_sockets) {
                if (listen.nPort == msg->network_old().port()) {
                    SNetSocket_t new_sock = create_connection_socket((uint64)msg->source_id(), 0, 0, msg->network_old().port(), listen.id, SOCKET_CONNECTED, msg->network_old().connection_id_from());
                    if (new_sock) {
                        struct SocketStatusCallback_t data;
                        data.m_hSocket = new_sock;
                        data.m_hListenSocket = listen.id;
                        data.m_steamIDRemote = (uint64)msg->source_id();
                        data.m_eSNetSocketState = k_ESNetSocketStateConnected; //TODO is this the right state?
                        callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
                    }
                }
            }
        } else if (msg->network_old().type() == Network_Old::CONNECTION_REQUEST_STEAMID) {
            for (auto & listen : listen_sockets) {
                if (listen.nVirtualP2PPort == msg->network_old().port()) {
                    SNetSocket_t new_sock = create_connection_socket((uint64)msg->source_id(), msg->network_old().port(), 0, 0, listen.id, SOCKET_CONNECTED, msg->network_old().connection_id_from());
                    if (new_sock) {
                        struct SocketStatusCallback_t data;
                        data.m_hSocket = new_sock;
                        data.m_hListenSocket = listen.id;
                        data.m_steamIDRemote = (uint64)msg->source_id();
                        data.m_eSNetSocketState = k_ESNetSocketStateConnected; //TODO is this the right state?
                        callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
                    }
                }
            }

        } else if (msg->network_old().type() == Network_Old::CONNECTION_ACCEPTED) {
            struct steam_connection_socket *socket = get_connection_socket(msg->network_old().connection_id());
            if (socket && socket->nPort && socket->status == SOCKET_CONNECTING && !socket->target.IsValid()) {
                socket->target = (uint64)msg->source_id();
            }

            if (socket && socket->status == SOCKET_CONNECTING && msg->source_id() == socket->target.ConvertToUint64()) {
                socket->status = SOCKET_CONNECTED;
                socket->other_id = msg->network_old().connection_id_from();
                struct SocketStatusCallback_t data;
                data.m_hSocket = socket->id;
                data.m_hListenSocket = socket->listen_id;
                data.m_steamIDRemote = socket->target;
                data.m_eSNetSocketState = k_ESNetSocketStateConnected; //TODO is this the right state?
                callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
            }
        } else if (msg->network_old().type() == Network_Old::CONNECTION_END) {
            struct steam_connection_socket *socket = get_connection_socket(msg->network_old().connection_id());
            if (socket && socket->status == SOCKET_CONNECTED && msg->source_id() == socket->target.ConvertToUint64()) {
                struct SocketStatusCallback_t data;
                socket->status = SOCKET_DISCONNECTED;
                data.m_hSocket = socket->id;
                data.m_hListenSocket = socket->listen_id;
                data.m_steamIDRemote = socket->target;
                data.m_eSNetSocketState = k_ESNetSocketStateRemoteEndDisconnected; //TODO is this the right state?
                callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
            }
        } else if (msg->network_old().type() == Network_Old::DATA) {
            struct steam_connection_socket *socket = get_connection_socket(msg->network_old().connection_id());
            if (socket && socket->status == SOCKET_CONNECTED && msg->source_id() == socket->target.ConvertToUint64()) {
                socket->data_packets.push_back(msg->network_old());
            }
        }
    }

    if (msg->has_low_level()) {
        if (msg->low_level().type() == Low_Level::DISCONNECT) {
            CSteamID source_id((uint64)msg->source_id());
            if (connection_exists(source_id)) {
                P2PSessionConnectFail_t data;
                data.m_steamIDRemote = source_id;
                data.m_eP2PSessionError = k_EP2PSessionErrorDestinationNotLoggedIn;
                callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
            }

            for (auto & socket : connection_sockets) {
                if (socket.target.ConvertToUint64() == msg->source_id()) {
                    struct SocketStatusCallback_t data;
                    socket.status = SOCKET_DISCONNECTED;
                    data.m_hSocket = socket.id;
                    data.m_hListenSocket = socket.listen_id;
                    data.m_steamIDRemote = socket.target;
                    data.m_eSNetSocketState = k_ESNetSocketStateConnectionBroken; //TODO is this the right state?
                    callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
                }
            }
        } else

        if (msg->low_level().type() == Low_Level::CONNECT) {
            
        }
    }
}
};
