/* 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/>.
*/

/*
    There are no public docs about this interface, this implementation
    is an imagination of how it might have been implemented
*/

#include "dll/steam_gamestats.h"
#include <unordered_map>


Steam_GameStats::Attribute_t::Attribute_t(AttributeType_t type)
    :type(type)
{
    switch (type)
    {
    case AttributeType_t::Float: f_data = 0; break;
    case AttributeType_t::Int64: ll_data = 0; break;
    case AttributeType_t::Int: n_data = 0; break;
    case AttributeType_t::Str: new (&s_data) std::string{}; break;
    
    default: PRINT_DEBUG("[X] invalid type %i", (int)type); break;
    }
}

Steam_GameStats::Attribute_t::Attribute_t(const Attribute_t &other)
    :type(type)
{
    switch (other.type)
    {
    case AttributeType_t::Int: n_data = other.n_data; break;
    case AttributeType_t::Str: new (&s_data) std::string(other.s_data); break;
    case AttributeType_t::Float: f_data = other.f_data; break;
    case AttributeType_t::Int64: ll_data = other.ll_data; break;
    
    default: PRINT_DEBUG("[X] invalid type %i", (int)other.type); break;
    }
}

Steam_GameStats::Attribute_t::Attribute_t(Attribute_t &&other)
    :type(type)
{
    switch (other.type)
    {
    case AttributeType_t::Int: n_data = other.n_data; break;
    case AttributeType_t::Str: new (&s_data) std::string(std::move(other.s_data)); break;
    case AttributeType_t::Float: f_data = other.f_data; break;
    case AttributeType_t::Int64: ll_data = other.ll_data; break;
    
    default: PRINT_DEBUG("[X] invalid type %i", (int)other.type); break;
    }
}

Steam_GameStats::Attribute_t::~Attribute_t()
{
    if (type == AttributeType_t::Str) {
        s_data.~basic_string();
    }
}


void Steam_GameStats::steam_gamestats_network_low_level(void *object, Common_Message *msg)
{
    //PRINT_DEBUG_ENTRY();

    auto inst = (Steam_GameStats *)object;
    inst->network_callback_low_level(msg);
}

void Steam_GameStats::steam_gamestats_run_every_runcb(void *object)
{
    //PRINT_DEBUG_ENTRY();

    auto inst = (Steam_GameStats *)object;
    inst->steam_run_callback();
}

Steam_GameStats::Steam_GameStats(class Settings *settings, class Networking *network, class SteamCallResults *callback_results, class SteamCallBacks *callbacks, class RunEveryRunCB *run_every_runcb)
{
    this->settings = settings;
    this->network = network;
    this->callback_results = callback_results;
    this->callbacks = callbacks;
    this->run_every_runcb = run_every_runcb;
    
    // this->network->setCallback(CALLBACK_ID_USER_STATUS, settings->get_local_steam_id(), &Steam_GameStats::steam_gamestats_network_low_level, this);
    this->run_every_runcb->add(&Steam_GameStats::steam_gamestats_run_every_runcb, this);

}

Steam_GameStats::~Steam_GameStats()
{
    // this->network->rmCallback(CALLBACK_ID_USER_STATUS, settings->get_local_steam_id(), &Steam_GameStats::steam_gamestats_network_low_level, this);
    this->run_every_runcb->remove(&Steam_GameStats::steam_gamestats_run_every_runcb, this);
}


uint64 Steam_GameStats::create_session_id() const
{
    static uint64 session_id = 0;
    session_id++;
    if (!session_id) session_id = 1; // not sure if 0 is a good idea
    return session_id;
}

bool Steam_GameStats::valid_stats_account_type(int8 nAccountType)
{
    switch ((EGameStatsAccountType)nAccountType) {
        case EGameStatsAccountType::k_EGameStatsAccountType_Steam:
        case EGameStatsAccountType::k_EGameStatsAccountType_Xbox:
        case EGameStatsAccountType::k_EGameStatsAccountType_SteamGameServer:
            return true;
    }

    return false;
}

Steam_GameStats::Table_t *Steam_GameStats::get_or_create_session_table(Session_t &session, const char *table_name)
{
    Table_t *table{};
    {
        auto table_it = std::find_if(session.tables.rbegin(), session.tables.rend(), [=](const std::pair<std::string, Table_t> &item){ return item.first == table_name; });
        if (session.tables.rend() == table_it) {
            auto& [key, val] = session.tables.emplace_back(std::pair<std::string, Table_t>{});
            table = &val;
        } else {
            table = &table_it->second;
        }
    }

    return table;
}

Steam_GameStats::Attribute_t *Steam_GameStats::get_or_create_session_att(const char *att_name, Session_t &session, AttributeType_t type_if_create)
{
    auto [ele_it, _] = session.attributes.emplace(att_name, type_if_create);
    return &ele_it->second;
}

Steam_GameStats::Attribute_t *Steam_GameStats::get_or_create_row_att(uint64 ulRowID, const char *att_name, Table_t &table, AttributeType_t type_if_create)
{
    auto &row = table.rows[static_cast<unsigned>(ulRowID)];
    auto [ele_it, _] = row.attributes.emplace(att_name, type_if_create);
    return &ele_it->second;
}

Steam_GameStats::Session_t* Steam_GameStats::get_last_active_session()
{
    auto active_session_it = std::find_if(sessions.rbegin(), sessions.rend(), [](std::pair<const uint64, Steam_GameStats::Session_t> item){ return !item.second.ended; });
    if (sessions.rend() == active_session_it) return nullptr; // TODO is this correct?

    return &active_session_it->second;
}


SteamAPICall_t Steam_GameStats::GetNewSession( int8 nAccountType, uint64 ulAccountID, int32 nAppID, RTime32 rtTimeStarted )
{
    // appid 550 calls this function once with client account id, and another time with server account id
    PRINT_DEBUG("%i, %llu, %i, %u", (int)nAccountType, ulAccountID, nAppID, rtTimeStarted);
    std::lock_guard lock(global_mutex);

    if ((settings->get_local_steam_id().ConvertToUint64() != ulAccountID) ||
        (nAppID < 0) ||
        (settings->get_local_game_id().AppID() != (uint32)nAppID) ||
        !valid_stats_account_type(nAccountType)) {

        GameStatsSessionIssued_t data_invalid{};
        data_invalid.m_bCollectingAny = false;
        data_invalid.m_bCollectingDetails = false;
        data_invalid.m_eResult = EResult::k_EResultInvalidParam;
        data_invalid.m_ulSessionID = 0;
        PRINT_DEBUG("[X] invalid param");

        auto ret = callback_results->addCallResult(data_invalid.k_iCallback, &data_invalid, sizeof(data_invalid));
        // the function returns SteamAPICall_t (call result), but in isteamstats.h you can see that a callback is also expected
        callbacks->addCBResult(data_invalid.k_iCallback, &data_invalid, sizeof(data_invalid));
        return ret;
    }

    auto session_id = create_session_id();
    Session_t new_session{};
    new_session.account_id = ulAccountID;
    new_session.nAccountType = (EGameStatsAccountType)nAccountType;
    new_session.rtTimeStarted = rtTimeStarted;
    sessions.insert_or_assign(session_id, new_session);

    GameStatsSessionIssued_t data{};
    data.m_bCollectingAny = true; // TODO is this correct?
    data.m_bCollectingDetails = true; // TODO is this correct?
    data.m_eResult = EResult::k_EResultOK;
    data.m_ulSessionID = session_id;
    PRINT_DEBUG("new session id = %llu", session_id);
    
    auto ret = callback_results->addCallResult(data.k_iCallback, &data, sizeof(data));
    // the function returns SteamAPICall_t (call result), but in isteamstats.h you can see that a callback is also expected
    callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
    return ret;
}

SteamAPICall_t Steam_GameStats::EndSession( uint64 ulSessionID, RTime32 rtTimeEnded, int nReasonCode )
{
    PRINT_DEBUG("%llu, %u, %i", ulSessionID, rtTimeEnded, nReasonCode);
    std::lock_guard lock(global_mutex);

    auto session_it = sessions.find(ulSessionID);
    if (sessions.end() == session_it) {
        GameStatsSessionClosed_t data_invalid{};
        data_invalid.m_eResult = EResult::k_EResultInvalidParam;
        data_invalid.m_ulSessionID = ulSessionID;
        PRINT_DEBUG("[X] session doesn't exist");

        auto ret = callback_results->addCallResult(data_invalid.k_iCallback, &data_invalid, sizeof(data_invalid));
        // the function returns SteamAPICall_t (call result), but in isteamstats.h you can see that a callback is also expected
        callbacks->addCBResult(data_invalid.k_iCallback, &data_invalid, sizeof(data_invalid));
        return ret;
    }

    auto& session = session_it->second;
    if (session.ended) {
        GameStatsSessionClosed_t data_invalid{};
        data_invalid.m_eResult = EResult::k_EResultExpired; // TODO is this correct?
        data_invalid.m_ulSessionID = ulSessionID;

        auto ret = callback_results->addCallResult(data_invalid.k_iCallback, &data_invalid, sizeof(data_invalid));
        // the function returns SteamAPICall_t (call result), but in isteamstats.h you can see that a callback is also expected
        callbacks->addCBResult(data_invalid.k_iCallback, &data_invalid, sizeof(data_invalid));
        return ret;
    }

    session.ended = true;
    session.rtTimeEnded = rtTimeEnded;
    session.nReasonCode = nReasonCode;

    GameStatsSessionClosed_t data{};
    data.m_eResult = EResult::k_EResultOK;
    data.m_ulSessionID = ulSessionID;
    PRINT_DEBUG("ended session");

    auto ret = callback_results->addCallResult(data.k_iCallback, &data, sizeof(data));
    // the function returns SteamAPICall_t (call result), but in isteamstats.h you can see that a callback is also expected
    callbacks->addCBResult(data.k_iCallback, &data, sizeof(data));
    return ret;
}

EResult Steam_GameStats::AddSessionAttributeInt( uint64 ulSessionID, const char* pstrName, int32 nData )
{
    PRINT_DEBUG("%llu, '%s'=%i", ulSessionID, pstrName, nData);
    std::lock_guard lock(global_mutex);

    auto session_it = sessions.find(ulSessionID);
    if (sessions.end() == session_it) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto& session = session_it->second;
    if (session.ended) return EResult::k_EResultExpired; // TODO is this correct?

    auto att = get_or_create_session_att(pstrName, session, AttributeType_t::Int);
    if (att->type != AttributeType_t::Int) return EResult::k_EResultFail; // TODO is this correct?

    att->n_data = nData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::AddSessionAttributeString( uint64 ulSessionID, const char* pstrName, const char *pstrData )
{
    PRINT_DEBUG("%llu, '%s'='%s'", ulSessionID, pstrName, pstrData);
    std::lock_guard lock(global_mutex);

    auto session_it = sessions.find(ulSessionID);
    if (sessions.end() == session_it) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto& session = session_it->second;
    if (session.ended) return EResult::k_EResultExpired; // TODO is this correct?

    auto att = get_or_create_session_att(pstrName, session, AttributeType_t::Str);
    if (att->type != AttributeType_t::Str) return EResult::k_EResultFail; // TODO is this correct?
    
    att->s_data = pstrData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::AddSessionAttributeFloat( uint64 ulSessionID, const char* pstrName, float fData )
{
    PRINT_DEBUG("%llu, '%s'=%f", ulSessionID, pstrName, fData);
    std::lock_guard lock(global_mutex);

    auto session_it = sessions.find(ulSessionID);
    if (sessions.end() == session_it) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto& session = session_it->second;
    if (session.ended) return EResult::k_EResultExpired; // TODO is this correct?

    auto att = get_or_create_session_att(pstrName, session, AttributeType_t::Float);
    if (att->type != AttributeType_t::Float) return EResult::k_EResultFail; // TODO is this correct?

    att->f_data = fData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}


EResult Steam_GameStats::AddNewRow( uint64 *pulRowID, uint64 ulSessionID, const char *pstrTableName )
{
    PRINT_DEBUG("%p, %llu, ['%s']", pulRowID, ulSessionID, pstrTableName);
    std::lock_guard lock(global_mutex);

    auto session_it = sessions.find(ulSessionID);
    if (sessions.end() == session_it) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto& session = session_it->second;
    if (session.ended) return EResult::k_EResultExpired; // TODO is this correct?

    auto table = get_or_create_session_table(session, pstrTableName);
    table->rows.emplace_back(Row_t{});
    if (pulRowID) *pulRowID = (uint64)(table->rows.size() - 1);
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::CommitRow( uint64 ulRowID )
{
    PRINT_DEBUG("%llu", ulRowID);
    std::lock_guard lock(global_mutex);
    
    auto active_session = get_last_active_session();
    if (!active_session) return EResult::k_EResultFail; // TODO is this correct?
    if (active_session->tables.empty()) return EResult::k_EResultFail; // TODO is this correct?

    auto &table = active_session->tables.back().second;
    if (ulRowID >= table.rows.size()) return EResult::k_EResultInvalidParam; // TODO is this correct?

    // TODO what if it was already committed ?
    auto& row = table.rows[static_cast<unsigned>(ulRowID)];
    row.committed = true;
    
    PRINT_DEBUG("committed successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::CommitOutstandingRows( uint64 ulSessionID )
{
    PRINT_DEBUG("%llu", ulSessionID);
    std::lock_guard lock(global_mutex);
    
    auto session_it = sessions.find(ulSessionID);
    if (sessions.end() == session_it) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto& session = session_it->second;
    if (session.ended) return EResult::k_EResultExpired; // TODO is this correct?

    if (session.tables.size()) {
        for (auto &row : session.tables.back().second.rows) {
            row.committed = true;
        }
    }
    PRINT_DEBUG("committed all successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::AddRowAttributeInt( uint64 ulRowID, const char *pstrName, int32 nData )
{
    PRINT_DEBUG("%llu, '%s'=%i", ulRowID, pstrName, nData);
    std::lock_guard lock(global_mutex);
    
    if (!pstrName) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto active_session = get_last_active_session();
    if (!active_session) return EResult::k_EResultFail; // TODO is this correct?
    if (active_session->tables.empty()) return EResult::k_EResultFail; // TODO is this correct?

    auto &table = active_session->tables.back().second;
    if (ulRowID >= table.rows.size()) return EResult::k_EResultInvalidParam; // TODO is this correct?

    auto att = get_or_create_row_att(ulRowID, pstrName, table, AttributeType_t::Int);
    if (att->type != AttributeType_t::Int) return EResult::k_EResultFail; // TODO is this correct?

    att->n_data = nData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::AddRowAtributeString( uint64 ulRowID, const char *pstrName, const char *pstrData )
{
    PRINT_DEBUG("%llu, '%s'='%s'", ulRowID, pstrName, pstrData);
    std::lock_guard lock(global_mutex);
    
    if (!pstrName || !pstrData) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto active_session = get_last_active_session();
    if (!active_session) return EResult::k_EResultFail; // TODO is this correct?
    if (active_session->tables.empty()) return EResult::k_EResultFail; // TODO is this correct?

    auto &table = active_session->tables.back().second;
    if (ulRowID >= table.rows.size()) return EResult::k_EResultInvalidParam; // TODO is this correct?

    auto att = get_or_create_row_att(ulRowID, pstrName, table, AttributeType_t::Str);
    if (att->type != AttributeType_t::Str) return EResult::k_EResultFail; // TODO is this correct?

    att->s_data = pstrData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::AddRowAttributeFloat( uint64 ulRowID, const char *pstrName, float fData )
{
    PRINT_DEBUG("%llu, '%s'=%f", ulRowID, pstrName, fData);
    std::lock_guard lock(global_mutex);
    
    if (!pstrName) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto active_session = get_last_active_session();
    if (!active_session) return EResult::k_EResultFail; // TODO is this correct?
    if (active_session->tables.empty()) return EResult::k_EResultFail; // TODO is this correct?

    auto &table = active_session->tables.back().second;
    if (ulRowID >= table.rows.size()) return EResult::k_EResultInvalidParam; // TODO is this correct?

    auto att = get_or_create_row_att(ulRowID, pstrName, table, AttributeType_t::Float);
    if (att->type != AttributeType_t::Float) return EResult::k_EResultFail; // TODO is this correct?

    att->f_data = fData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}


EResult Steam_GameStats::AddSessionAttributeInt64( uint64 ulSessionID, const char *pstrName, int64 llData )
{
    PRINT_DEBUG("%llu, '%s'=%lli", ulSessionID, pstrName, llData);
    std::lock_guard lock(global_mutex);

    auto session_it = sessions.find(ulSessionID);
    if (sessions.end() == session_it) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto& session = session_it->second;
    if (session.ended) return EResult::k_EResultExpired; // TODO is this correct?

    auto att = get_or_create_session_att(pstrName, session, AttributeType_t::Int64);
    if (att->type != AttributeType_t::Int64) return EResult::k_EResultFail; // TODO is this correct?

    att->ll_data = llData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}

EResult Steam_GameStats::AddRowAttributeInt64( uint64 ulRowID, const char *pstrName, int64 llData )
{
    PRINT_DEBUG("%llu, '%s'=%lli", ulRowID, pstrName, llData);
    std::lock_guard lock(global_mutex);
    
    if (!pstrName) return EResult::k_EResultInvalidParam; // TODO is this correct?
    
    auto active_session = get_last_active_session();
    if (!active_session) return EResult::k_EResultFail; // TODO is this correct?
    if (active_session->tables.empty()) return EResult::k_EResultFail; // TODO is this correct?

    auto &table = active_session->tables.back().second;
    if (ulRowID >= table.rows.size()) return EResult::k_EResultInvalidParam; // TODO is this correct?

    auto att = get_or_create_row_att(ulRowID, pstrName, table, AttributeType_t::Int64);
    if (att->type != AttributeType_t::Int64) return EResult::k_EResultFail; // TODO is this correct?

    att->ll_data = llData;
    PRINT_DEBUG("added successfully");
    return EResult::k_EResultOK;
}



// --- steam callbacks

std::string Steam_GameStats::sanitize_csv_value(std::string_view value)
{
    // ref: https://en.wikipedia.org/wiki/Comma-separated_values
    // double quotes must be represented by a pair of double quotes
    auto val_str = common_helpers::str_replace_all(value, "\"", "\"\"");
    // multiline values aren't supported by all parsers
    val_str = common_helpers::str_replace_all(val_str, "\r\n", "\n");
    val_str = common_helpers::str_replace_all(val_str, "\n", " ");
    return val_str;
}

void Steam_GameStats::save_session_to_disk(Steam_GameStats::Session_t &session, uint64 session_id)
{
    auto folder = std::to_string(session.account_id) + "_" + std::to_string(session.rtTimeStarted) + "_" + std::to_string(session_id);
    auto folder_p = std::filesystem::u8path(settings->steam_game_stats_reports_dir) / std::filesystem::u8path(folder);
    auto folder_u8_str = folder_p.u8string();

    // save session attributes
    if (session.attributes.size()) {
        std::stringstream ss{};
        ss << "Session attribute,Value\n";
        for (const auto& [name, val] : session.attributes) {
            std::string val_str{};
            switch (val.type) {
                case AttributeType_t::Int: val_str = std::to_string(val.n_data); break;
                case AttributeType_t::Str: val_str = val.s_data; break;
                case AttributeType_t::Float: val_str = std::to_string(val.f_data); break;
                case AttributeType_t::Int64: val_str = std::to_string(val.ll_data); break;
            }

            val_str = sanitize_csv_value(val_str);
            auto name_str = sanitize_csv_value(name);
            ss << "\"" << name_str << "\",\"" << val_str << "\"\n";
        }
        auto ss_str = ss.str();
        Local_Storage::store_file_data(folder_u8_str, "session_attributes.csv", ss_str.c_str(), (unsigned int)ss_str.size());
    }

    // save each table
    for (const auto& [table_name, table_data] : session.tables) {
        bool rows_has_attributes = std::any_of(table_data.rows.begin(), table_data.rows.end(), [](const Steam_GameStats::Row_t &item) {
            return item.attributes.size() > 0;
        });

        if (!rows_has_attributes) continue;

        // convert the data representation to be column oriented
        // key=column header/title
        // value = list of column values
        std::unordered_map<std::string, std::vector<const Attribute_t*>> columns{};
        for (size_t row_idx = 0; row_idx < table_data.rows.size(); ++row_idx) {
            const auto &row = table_data.rows[row_idx];
            for (const auto& [att_name, att_val] : row.attributes) {
                auto [column_it, new_column] = columns.emplace(att_name, std::vector<const Attribute_t*>{});
                auto &column_values = column_it->second;
                // when adding new column make sure we have correct rows count
                if (new_column) {
                    column_values.assign(table_data.rows.size(), nullptr);
                }
                // add the row value in its correct place
                column_values[row_idx] = &att_val;
            }
        }

        std::stringstream ss_table{};
        // write header
        bool first_header_atom = true;
        for (const auto& [col_name, _] : columns) {
            auto csv_col_name = sanitize_csv_value(col_name);
            if (first_header_atom) {
                first_header_atom = false;
                ss_table << "\"" << csv_col_name << "\"";
            } else {
                ss_table << ",\"" << csv_col_name << "\"";
            }
        }
        ss_table << "\n";
        // write values
        for (size_t row_idx = 0; row_idx < table_data.rows.size(); ++row_idx) {
            bool first_col_cell = true;
            for (const auto& [_, col_values] : columns) {
                auto &cell_val = col_values[row_idx];
                
                std::string val_str{};
                switch (cell_val->type) {
                    case AttributeType_t::Int: val_str = std::to_string(cell_val->n_data); break;
                    case AttributeType_t::Str: val_str = cell_val->s_data; break;
                    case AttributeType_t::Float: val_str = std::to_string(cell_val->f_data); break;
                    case AttributeType_t::Int64: val_str = std::to_string(cell_val->ll_data); break;
                }

                val_str = sanitize_csv_value(val_str);
                if (first_col_cell) {
                    first_col_cell = false;
                    ss_table << "\"" << val_str << "\"";
                } else {
                    ss_table << ",\"" << val_str << "\"";
                }
            }
        }
        ss_table << "\n";
        auto ss_str = ss_table.str();
        Local_Storage::store_file_data(folder_u8_str, table_name.c_str(), ss_str.c_str(), (unsigned int)ss_str.size());

    }
}

void Steam_GameStats::steam_run_callback()
{
    // remove ended sessions that are inactive
    auto session_it = sessions.begin();
    auto now_epoch_sec = std::chrono::duration_cast<std::chrono::seconds>(
        std::chrono::system_clock::now().time_since_epoch()
    );
    while (sessions.end() != session_it) {
        bool should_remove = false;

        auto &session = session_it->second;
        if (session.ended) {
            if (!session.saved_to_disk) {
                session.saved_to_disk = true;
                if (settings->steam_game_stats_reports_dir.size()) {
                    save_session_to_disk(session, session_it->first);
                }
            }

            if ( (now_epoch_sec.count() - (long long)session.rtTimeEnded) >= MAX_DEAD_SESSION_SECONDS ) {
                should_remove = true;
                PRINT_DEBUG("removing outdated session id=%llu", session_it->first);
            }
        }

        if (should_remove) {
            session_it = sessions.erase(session_it);
        } else {
            ++session_it;
        }
    }
}



// --- networking callbacks

// user connect/disconnect
void Steam_GameStats::network_callback_low_level(Common_Message *msg)
{
    switch (msg->low_level().type())
    {
    case Low_Level::CONNECT:
        // nothing
    break;
    
    case Low_Level::DISCONNECT:
        // nothing
    break;
    
    default:
        PRINT_DEBUG("unknown type %i", (int)msg->low_level().type());
    break;
    }
}