#pragma once

/*                          MOUNT CONTROL COMPONENTS LIBRARY                            */

/*                          BASIC NETWORK PROTOCOL DEFINITIONS                          */



#include <algorithm>
#include <string_view>
#include "mcc_angle.h"
#include "mcc_generics.h"
#include "mcc_utils.h"

namespace mcc::network
{

/*
 *  The network protocol is the ASCII-based, case-sensitive textual protocol.
 *  The "client-server" communication is performed through messages.
 *  The message is a minimal unit of this communication.
 *  The model of network communication is a simple "client-server" one, i.e.,
 *  client asks - server responds.
 *
 *  network communication message format:
 *      <keyword>[[<key-param-delim>]<param1>[<param-param-delim>][<param2>]...]<stop-seq>
 *
 *      where
 *          <keyword> - mandatory message keyword (one or more ASCII symbols)
 *          <key-param-delim>
 *
 *      e.g.
 *      "TARGET 12:23:45.56 00:32:21.978\n"
 */


/*    low-level network message format definitions   */

static constexpr std::string_view MCC_COMMPROTO_STOP_SEQ = "\n";
static constexpr std::string_view MCC_COMMPROTO_KEYPARAM_DELIM_SEQ = " ";
static constexpr std::string_view MCC_COMMPROTO_PARAMPARAM_DELIM_SEQ = ";";
static constexpr std::string_view MCC_COMMPROTO_RANGEPARAM_DELIM_SEQ = ",";


/*    server special keywords    */

static constexpr std::string_view MCC_COMMPROTO_KEYWORD_SERVER_ACK_STR = "ACK";      // ACK
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_SERVER_ERROR_STR = "ERROR";  // mount operational error
// pre-defined errors
static constexpr std::string_view MCC_COMMPROTO_SERVER_ERROR_INVKEY_STR = "INVKEY";  // invalid keyword
static constexpr std::string_view MCC_COMMPROTO_SERVER_ERROR_INVPAR_STR = "INVPAR";  // invalid parameter


/*    server control keywords     */

static constexpr std::string_view MCC_COMMPROTO_KEYWORD_RESTART_SERVER_STR = "RESTART";  // restart server


/*                  BELOW IS ONE OF THE PROTOCOL OPTIONS CORRESPONDING MCC_GENERIC_MOUNT_C CONCEPT */


/*    predefined parameters    */

static constexpr std::string_view MCC_COMMPROTO_COORD_KIND_RADEC_ICRS = "RADEC_ICRS";  // ICRS RA and DEC
static constexpr std::string_view MCC_COMMPROTO_COORD_KIND_RADEC = "RADEC";            // apparent RA and DEC
static constexpr std::string_view MCC_COMMPROTO_COORD_KIND_HADEC = "HADEC";            // apparent HA and DEC
static constexpr std::string_view MCC_COMMPROTO_COORD_KIND_AZZD = "AZZD";              // azimuth and zenithal distance
static constexpr std::string_view MCC_COMMPROTO_COORD_KIND_AZALT = "AZALT";            // azimuth and altitude
static constexpr std::string_view MCC_COMMPROTO_COORD_KIND_XY = "XY";                  // hardware (encoder) coordinates


// static constexpr MccCoordPairKind mcc_str2pairkind(std::string_view spair)
// {
//     return spair == MCC_COMMPROTO_COORD_KIND_RADEC_ICRS ? MccCoordPairKind::COORDS_KIND_RADEC_ICRS
//            : spair == MCC_COMMPROTO_COORD_KIND_RADEC    ? MccCoordPairKind::COORDS_KIND_RADEC_APP
//            : spair == MCC_COMMPROTO_COORD_KIND_HADEC    ? MccCoordPairKind::COORDS_KIND_HADEC_APP
//            : spair == MCC_COMMPROTO_COORD_KIND_AZZD     ? MccCoordPairKind::COORDS_KIND_AZZD
//            : spair == MCC_COMMPROTO_COORD_KIND_AZALT    ? MccCoordPairKind::COORDS_KIND_AZALT
//            : spair == MCC_COMMPROTO_COORD_KIND_XY       ? MccCoordPairKind::COORDS_KIND_XY
//                                                         : MccCoordPairKind::COORDS_KIND_GENERIC;
// }

template <mcc::traits::mcc_char_range R>
static constexpr MccCoordPairKind mcc_str2pairkind(R&& spair)
{
    if constexpr (std::is_pointer_v<std::decay_t<R>>) {
        return mcc_str2pairkind(std::string_view{spair});
    }

    const auto hash = mcc::utils::FNV1aHash(std::forward<R>(spair));

    return hash == mcc::utils::FNV1aHash(MCC_COMMPROTO_COORD_KIND_RADEC_ICRS) ? MccCoordPairKind::COORDS_KIND_RADEC_ICRS
           : hash == mcc::utils::FNV1aHash(MCC_COMMPROTO_COORD_KIND_RADEC)    ? MccCoordPairKind::COORDS_KIND_RADEC_APP
           : hash == mcc::utils::FNV1aHash(MCC_COMMPROTO_COORD_KIND_HADEC)    ? MccCoordPairKind::COORDS_KIND_HADEC_APP
           : hash == mcc::utils::FNV1aHash(MCC_COMMPROTO_COORD_KIND_AZZD)     ? MccCoordPairKind::COORDS_KIND_AZZD
           : hash == mcc::utils::FNV1aHash(MCC_COMMPROTO_COORD_KIND_AZALT)    ? MccCoordPairKind::COORDS_KIND_AZALT
           : hash == mcc::utils::FNV1aHash(MCC_COMMPROTO_COORD_KIND_XY)       ? MccCoordPairKind::COORDS_KIND_XY
                                                                              : MccCoordPairKind::COORDS_KIND_GENERIC;
}


static constexpr std::string_view mcc_pairkind2str(MccCoordPairKind kind)
{
    return kind == MccCoordPairKind::COORDS_KIND_RADEC_ICRS  ? MCC_COMMPROTO_COORD_KIND_RADEC_ICRS
           : kind == MccCoordPairKind::COORDS_KIND_RADEC_APP ? MCC_COMMPROTO_COORD_KIND_RADEC
           : kind == MccCoordPairKind::COORDS_KIND_HADEC_APP ? MCC_COMMPROTO_COORD_KIND_HADEC
           : kind == MccCoordPairKind::COORDS_KIND_AZZD      ? MCC_COMMPROTO_COORD_KIND_AZZD
           : kind == MccCoordPairKind::COORDS_KIND_AZALT     ? MCC_COMMPROTO_COORD_KIND_AZALT
           : kind == MccCoordPairKind::COORDS_KIND_XY        ? MCC_COMMPROTO_COORD_KIND_XY
                                                             : "UNKNOWN";
}


/*    keywords    */

// NOTE: THE COORDINATES AND TIME-RELATED QUANTITIES CAN BE EXPRESSED IN THE TWO FORMATS:
//       1) fixed-point real number, e.g. 123.43987537359 or -0.09775
//       2) sexagesimal number, e.g. 10:43:43.12 or -123:54:12.435
//
//       IN THE FIRST CASE ALL NUMBERS MUST BE INTERPRETATED AS DEGREES,
//       IN THE SECOND CASE NUMBERS MUST BE INTERPRETATED ACCORDING TO ITS TYPE:
//           ALL TIME-RELATED QUANTITIES AND RA/HA COORDINATES MUST BE EXPRESSED
//           IN FORMAT 'HOURS:MINUTES:SECONDS', WHILE DEC/ALT/AZ/ZD COORDINATES MUST
//           BE EXPRESSED AS '+/-DEGREES:ARCMINUTES:ARCSECONDS'
//
//       USER-ENTERED (FROM NETWORK CLIENTS) COORDINATE PAIR CAN BE PROVIDED IN A MIXED FORM, I.E.,
//           12.34436658678 10:32:11.432 or
//           10:32:11.432 12.34436658678
//
//       SERVER-RESPONDED COORDINATES ARE ALWAYS IN THE SAME FORMAT, SEXAGESIMAL OR FIXED-POINT
//

// format of output coordinates:
//    "COORDFMT FMT-type\n"
//    e.g.:
//    "COORDFMT SGM\n"
//    "COORDFMT\n"
//
// server must return "ACK" or "ERROR INVPAR" in the case of 'set'-operation and
// "ACK COORDFMT FMT-type" in the case of 'get'-operation
//    e.g.:
//    "COORDFMT FIX\n" -> "ACK\n"
//    "COORDFMT SXT\n" -> "ERROR INVPAR\n" (invalid parameter of format type)
//    "COORDFMT\n" -> "ACK COORDFMT FIX\n"
//

static constexpr std::string_view MCC_COMMPROTO_KEYWORD_COORDFMT_STR = "COORDFMT";
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_COORDFMT_SEXGM_STR = "SGM";  // sexagesimal
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_COORDFMT_FIXED_STR = "FIX";  // fixed point


// precision (number of decimal places) of returned coordinates:
//     "COORDPREC seconds-prec arcseconds-prec\n"
//     seconds-prec - precision of hour-based coordinates (RA and HA) or time-related quantities
//     arcseconds-prec - precision of degree-based coordinates (DEC, AZ, ZD, ALT)
//         precision must be given as non-negative integer number
//     e.g.
//     "COORDPREC 2 1\n" (output sexagesimal RA=12:34:56.67, DEC=32:54:21.9)
//
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_COORDPREC_STR = "COORDPREC";


// set/get target coordinates
//     "TARGET X-coord Y-coord XY-kind\n", if 'XY-kind' is omitted then one should assume RADEC_ICRS
//     e.g.:
//     "TARGET 12.7683487 10:23:09.75 AZZD\n"
//     "TARGET HADEC\n"
//     "TARGET\n"
//
// server must return "ACK" or "ERROR INVPAR" in the case of 'set'-operation and
// "ACK TARGET X-coord Y-coord XY-kind" in the case of 'get'-operation
//     e.g.:
//     "TARGET 12.7683487 10:23:09.75 AZZD\n" -> "ACK\n"
//     "TARGET 12.7683487 10:23:09.75 AZZE\n" -> "ERROR INVPAR\n" (invalid parameter of coordinates pair kind)
//
//     "TARGET HADEC\n" -> "ACK TARGET 20:21:56.32 -01:32:34.2 HADEC\n"
//     "TARGET\n"  -> "ACK TARGET 20:21:56.32 -01:32:34.2 RADEC_ICRS\n"
//

static constexpr std::string_view MCC_COMMPROTO_KEYWORD_TARGET_STR = "TARGET";

// get mount coordinates:
//     "MOUNT coord-kind", if 'coord-kind' is omitted then coordinates are according to mount type,
//                         i.e., HADEC for equathorial-type mount and AZZD for alt-azimuthal one
//     e.g.:
//     "MOUNT RADEC\n" (get current apparent RA and DEC mount coordinates)
//
// server must return "ACK MOUNT X-coord Y-coord XY-kind" or "ERROR INVPAR"
//     e.g.
//     "MOUNT AZALT\n" -> "ACK MOUNT 1.2332325 54.23321312 AZALT\n"
//     "MOUNT AZAL\n" -> "ERROR INVPAR\n" (invalid parameter of coordinates pair kind)
//     "MOUNT\n" -> "ACK MOUNT 1.2332325 54.23321312 AZZD\n" for alt-azimuthal mount
//     "MOUNT\n" -> "ACK MOUNT 1.2332325 54.23321312 HADEC\n" for equathorial mount

static constexpr std::string_view MCC_COMMPROTO_KEYWORD_MOUNT_STR = "MOUNT";


static constexpr std::string_view MCC_COMMPROTO_KEYWORD_TELEMETRY_STR = "TELEMETRY";

// init mount
//     "INIT\n"
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_INIT_STR = "INIT";

// stop any movements
//     "STOP\n"
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_STOP_STR = "STOP";

// slew mount and track target:
//     "SLEW\n"
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_SLEW_STR = "SLEW";

// slew mount and stop:
//     "MOVE\n"
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_MOVE_STR = "MOVE";

// track target
//     "TRACK\n"
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_TRACK_STR = "TRACK";

// get mount status
//     "STATUS\n"
static constexpr std::string_view MCC_COMMPROTO_KEYWORD_STATUS_STR = "STATUS";

// valid keywords
static constexpr std::array MCC_COMMPROTO_VALID_KEYS = {
    MCC_COMMPROTO_KEYWORD_SERVER_ACK_STR, MCC_COMMPROTO_KEYWORD_SERVER_ERROR_STR, MCC_COMMPROTO_KEYWORD_COORDFMT_STR,
    MCC_COMMPROTO_KEYWORD_COORDPREC_STR,  MCC_COMMPROTO_KEYWORD_TARGET_STR,       MCC_COMMPROTO_KEYWORD_MOUNT_STR,
    MCC_COMMPROTO_KEYWORD_TELEMETRY_STR,  MCC_COMMPROTO_KEYWORD_INIT_STR,         MCC_COMMPROTO_KEYWORD_STOP_STR,
    MCC_COMMPROTO_KEYWORD_SLEW_STR,       MCC_COMMPROTO_KEYWORD_MOVE_STR,         MCC_COMMPROTO_KEYWORD_TRACK_STR,
    MCC_COMMPROTO_KEYWORD_STATUS_STR};


// hashes of valid keywords
static constexpr std::array MCC_COMMPROTO_VALID_KEYS_HASH = []<size_t... Is>(std::index_sequence<Is...>) {
    return std::array{mcc::utils::FNV1aHash(MCC_COMMPROTO_VALID_KEYS[Is])...};
}(std::make_index_sequence<MCC_COMMPROTO_VALID_KEYS.size()>());


static constexpr size_t MCC_COMMPROTO_KEYWORD_SERVER_ACK_HASH =
    mcc::utils::FNV1aHash(MCC_COMMPROTO_KEYWORD_SERVER_ACK_STR);

static constexpr size_t MCC_COMMPROTO_KEYWORD_SERVER_ERROR_HASH =
    mcc::utils::FNV1aHash(MCC_COMMPROTO_KEYWORD_SERVER_ERROR_STR);

static constexpr size_t MCC_COMMPROTO_KEYWORD_TARGET_HASH = mcc::utils::FNV1aHash(MCC_COMMPROTO_KEYWORD_TARGET_STR);

static constexpr size_t MCC_COMMPROTO_KEYWORD_MOUNT_HASH = mcc::utils::FNV1aHash(MCC_COMMPROTO_KEYWORD_MOUNT_STR);


template <traits::mcc_char_range T = std::string_view, std::ranges::output_range<T> RT = std::vector<T>>
struct mcc_netmsg_parse_result_t {
    size_t keyword_hash;
    T keyword;
    RT params;
};


// network message parsing result class concept
template <typename T>
concept mcc_netmsg_parse_result_c = requires(T t) {
    requires std::same_as<decltype(t.keyword_hash), size_t>;  // hash of keyword
    requires traits::mcc_char_range<decltype(t.keyword)>;     // keyword char-range representation
    // a range of parameters char-range representations
    requires std::ranges::output_range<decltype(t.params), decltype(t.keyword)>;
};

// the function returns hash of message keyword
//     if 'from_server' is true then given network message is considered as a server response, i.e.,
//     valid keywords are "ACK" or "ERROR"
//
//     the funtions returns false in the case of invalid message format and true otherwise
//
template <traits::mcc_input_char_range IR, mcc_netmsg_parse_result_c ResT>
bool mcc_parse_netmsg(const IR& netmsg, ResT& parse_res, bool from_server = false)
{
    if (std::ranges::size(netmsg) == 0) {
        return false;
    };

    auto found = std::ranges::search(netmsg, MCC_COMMPROTO_KEYPARAM_DELIM_SEQ);
    if (std::distance(netmsg.begin(), found.begin()) == 0) {
        return false;
    }

    const size_t hash = mcc::utils::FNV1aHash(netmsg.begin(), found.begin());
    auto it = std::ranges::find(MCC_COMMPROTO_VALID_KEYS_HASH, hash);
    if (it == MCC_COMMPROTO_VALID_KEYS_HASH.end()) {
        return false;
    }

    if (from_server) {  // only ACK or ERROR
        auto ok = hash == MCC_COMMPROTO_VALID_KEYS_HASH[0] || hash == MCC_COMMPROTO_VALID_KEYS_HASH[1];
        if (!ok) {
            return false;
        }
    }

    parse_res.keyword_hash = hash;
    parse_res.keyword = {netmsg.begin(), found.begin()};

    auto pars = netmsg | std::views::drop(std::distance(netmsg.begin(), found.end())) |
                std::views::split(MCC_COMMPROTO_PARAMPARAM_DELIM_SEQ);

    decltype(parse_res.params) res;

    for (auto const& el : pars) {  // parameters
        std::back_inserter(res) = {el.begin(), el.end()};
    }

    parse_res.params = std::move(res);

    return true;
}


// construct network message
//     the function returns false if input keyword is not valid one (see MCC_COMMPROTO_VALID_KEYS)!
template <typename... PTs>
bool mcc_netmsg_construct(traits::mcc_output_char_range auto& msg,
                          traits::mcc_input_char_range auto const& keyword,
                          PTs... params)
{
    const size_t hash = mcc::utils::FNV1aHash(keyword);
    if (!std::ranges::contains(MCC_COMMPROTO_VALID_KEYS_HASH, hash)) {
        return false;
    }

    msg = {keyword.begin(), keyword.end()};

    if constexpr (sizeof...(PTs)) {
        std::ranges::copy(MCC_COMMPROTO_KEYPARAM_DELIM_SEQ, std::back_inserter(msg));

        [&msg]<typename T, typename... Ts>(this auto&& self, const T& par, const Ts&... pars) {
            if constexpr (std::is_arithmetic_v<T>) {
                std::ranges::copy(std::to_string(par), std::back_inserter(msg));
            } else if constexpr (std::convertible_to<T, std::string>) {
                std::ranges::copy(static_cast<std::string>(par), std::back_inserter(msg));
            } else if constexpr (std::constructible_from<std::string, T>) {
                std::ranges::copy(std::string(par), std::back_inserter(msg));
            } else if constexpr (traits::mcc_char_range<T>) {
                std::ranges::copy(std::string(par.begin(), par.end()), std::back_inserter(msg));
            } else if constexpr (std::same_as<T, MccCoordPairKind>) {
                std::ranges::copy(mcc_pairkind2str(par), std::back_inserter(msg));
            } else {
                static_assert(false, "UNSUPPORTED TYPE!!!");
            }

            if constexpr (sizeof...(Ts)) {
                std::ranges::copy(MCC_COMMPROTO_PARAMPARAM_DELIM_SEQ, std::back_inserter(msg));

                std::forward<decltype(self)>(self)(pars...);
            }
        }(params...);
    }

    return true;
}


// the function convert given network message parsing result class to
// celestial point coordinates according to parsed message parameters.
//
// It is assumed that the coordinates and their type are contained in the consecutive elements of the input array
// starting from the element 'from_idx' (zero-based):
//
//    parse_res.params[...,  X-COORD, Y-COORD, XY-KIND, ...]
//
//    th last parameter 'XY-KIND' can be omitted and, in this case, 'default_kind' is assumed
//
// NOTE: IT IS ASSUMED THAT THE COORDINATES ARE REPRESENTED AS DEGREES EXPRESSED BY THE NUMBER WITH A FLOATING POINT
//       OR IN SEXAGESIMAL FORM. IN THE CASE OF SEXAGESIMAL FORM THE TYPE (DEGREES OR HOURS) OF THE COORDINATE
//       REPRESENTATION IS DETERMINED BY 'XY-KIND', E.G.:
//           parse_res.params[...,  "12:34:52.123", "23:43:56.12", "HADEC", ...]
//               'HADEC' STRING FOR 'XY-KIND' DETERMINES THE FIRST COORDINATE (HOUR ANGLE)
//               AS AN ANGLE IN HOUR FORM WHILE THE SECOND ONE (DECLINATION) IN DEGREES
//
//
// The function returns false if it can not convert coordinate string to number or the 'XY-KIND' string is invalid
//
bool mcc_netmsg_get_cpoint(mcc_netmsg_parse_result_c auto const& parse_res,
                           size_t from_idx,
                           mcc_celestial_point_c auto& cpoint,
                           MccCoordPairKind default_kind)
    requires std::ranges::contiguous_range<decltype(parse_res.keyword)>
{
    if (std::ranges::size(parse_res.params) < (from_idx + 2)) {
        return false;
    }

    MccCoordPairKind kind = default_kind;

    if (std::ranges::size(parse_res.params) > (from_idx + 2)) {
        kind = mcc_str2pairkind(parse_res.params[from_idx + 2]);
        if (kind == MccCoordPairKind::COORDS_KIND_GENERIC) {
            return false;
        }
    }

    std::optional<double> ang1, ang2;

    switch (kind) {
        case mcc::MccCoordPairKind::COORDS_KIND_RADEC_ICRS:
        case mcc::MccCoordPairKind::COORDS_KIND_RADEC_APP:
        case mcc::MccCoordPairKind::COORDS_KIND_HADEC_APP:
            ang1 = utils::parsAngleString(parse_res.params[from_idx], true);
            break;
        default:
            ang1 = utils::parsAngleString(parse_res.params[from_idx]);
    }
    if (!ang1) {
        return false;
    }

    ang2 = utils::parsAngleString(parse_res.params[from_idx + 1]);
    if (!ang2) {
        return false;
    }

    if (kind != mcc::MccCoordPairKind::COORDS_KIND_RADEC_ICRS) {
        mcc_tp2tp(std::chrono::system_clock::now(), cpoint.time_point);
    } else {
        // J2000.0: 11:58:55.816 1 January 2000 UTC
        auto tp = std::chrono::sys_days(std::chrono::year_month_day(std::chrono::January / std::chrono::day(1) /
                                                                    std::chrono::year(2000))) +
                  std::chrono::hours(11) + std::chrono::minutes(58) + std::chrono::milliseconds(55816);
        mcc_tp2tp(tp, cpoint.time_point);
    }

    cpoint.pair_kind = kind;

    cpoint.X = MccAngle(ang1.value(), mcc::MccDegreeTag{});  // to radians
    cpoint.Y = MccAngle(ang2.value(), mcc::MccDegreeTag{});  // to radians

    return true;
}


template <typename T>
concept mcc_netmsg_valid_keys_c = requires(T t) {
    // std::array of valid message keywords
    []<size_t N>(std::array<std::string_view, N>) {
        // to ensure T::NETMSG_VALID_KEYWORDS can be used as compile-time constant
        static constexpr auto v0 = T::NETMSG_VALID_KEYWORDS[0];
        return v0;
    }(T::NETMSG_VALID_KEYWORDS);

    // std::array of valid message keywords hashes
    []<size_t N>(std::array<size_t, N>) {
        // to ensure T::NETMSG_VALID_KEYWORD_HASHES can be used as compile-time constant
        static constexpr auto v0 = T::NETMSG_VALID_KEYWORD_HASHES[0];
        return v0;
    }(T::NETMSG_VALID_KEYWORD_HASHES);

    requires T::NETMSG_VALID_KEYWORDS.size() == T::NETMSG_VALID_KEYWORD_HASHES.size();
};


struct MccNetMessageValidKeywords {
    static constexpr std::array NETMSG_VALID_KEYWORDS = {
        MCC_COMMPROTO_KEYWORD_SERVER_ACK_STR, MCC_COMMPROTO_KEYWORD_SERVER_ERROR_STR,
        MCC_COMMPROTO_KEYWORD_COORDFMT_STR,   MCC_COMMPROTO_KEYWORD_COORDPREC_STR,
        MCC_COMMPROTO_KEYWORD_TARGET_STR,     MCC_COMMPROTO_KEYWORD_MOUNT_STR,
        MCC_COMMPROTO_KEYWORD_TELEMETRY_STR,  MCC_COMMPROTO_KEYWORD_INIT_STR,
        MCC_COMMPROTO_KEYWORD_STOP_STR,       MCC_COMMPROTO_KEYWORD_SLEW_STR,
        MCC_COMMPROTO_KEYWORD_MOVE_STR,       MCC_COMMPROTO_KEYWORD_TRACK_STR,
        MCC_COMMPROTO_KEYWORD_STATUS_STR};


    // hashes of valid keywords
    static constexpr std::array NETMSG_VALID_KEYWORD_HASHES = []<size_t... Is>(std::index_sequence<Is...>) {
        return std::array{mcc::utils::FNV1aHash(NETMSG_VALID_KEYWORDS[Is])...};
    }(std::make_index_sequence<NETMSG_VALID_KEYWORDS.size()>());

    static std::expected<size_t, std::error_code> isKeywordValid(std::string_view key)
    {
        const auto hash = utils::FNV1aHash(key);

        for (auto const& h : NETMSG_VALID_KEYWORD_HASHES) {
            if (h == hash) {
                return h;
            }
        }

        return std::unexpected(std::make_error_code(std::errc::invalid_argument));
    }
};

static_assert(mcc_netmsg_valid_keys_c<MccNetMessageValidKeywords>, "");


template <mcc_netmsg_valid_keys_c BASE_T, traits::mcc_output_char_range BYTEREPR_T>
class MccNetMessage
{
public:
    typedef BASE_T valid_keys_t;
    typedef BYTEREPR_T byte_repr_t;

    template <traits::mcc_input_char_range KT, typename... PTs>
    MccNetMessage(KT&& key, PTs&&... params)
    {
        construct(std::forward<KT>(key), std::forward<PTs>(params)...);
    }

    template <traits::mcc_input_char_range KT>
    bool withKey(const KT& key)
    {
        return utils::FNV1aHash(key) == _keywordHash;
    }

    template <typename T, typename DeserFuncT>
    std::expected<T, std::error_code> params(DeserFuncT&& deser_func)
    {
        T val;

        auto ec = deser_func(_params, val);
        if (ec) {
            return std::unexpect(ec);
        } else {
            return val;
        }
    }

    template <typename T>
    std::expected<T, std::error_code> params()
    {
        return params<T>(utils::MccSimpleDeserializer{}.setRangeDelim(MCC_COMMPROTO_RANGEPARAM_DELIM_SEQ));
    }

    template <traits::mcc_input_char_range KT, typename... PTs>
    std::error_code construct(KT&& key, PTs&&... params)
    {
        if (!std::ranges::size(key)) {
            return std::make_error_code(std::errc::invalid_argument);
        }

        auto r = valid_keys_t::isKeywordValid(key);
        if (!r) {
            return r.error();
        }

        _keywordHash = r.value();

        _msgBuffer = BYTEREPR_T{};

        std::ranges::copy(key, std::back_inserter(_msgBuffer));
        _keyword = {_msgBuffer.begin(), _msgBuffer.end()};

        _params = std::string_view{};

        if constexpr (sizeof...(PTs)) {
            std::ranges::copy(MCC_COMMPROTO_KEYPARAM_DELIM_SEQ, std::back_inserter(_msgBuffer));

            [this]<typename T, typename... Ts>(this auto&& self, const T& par, const Ts&... pars) {
                if constexpr (std::is_arithmetic_v<T>) {
                    std::ranges::copy(std::to_string(par), std::back_inserter(_msgBuffer));
                } else if constexpr (std::convertible_to<T, std::string>) {
                    std::ranges::copy(static_cast<std::string>(par), std::back_inserter(_msgBuffer));
                } else if constexpr (std::constructible_from<std::string, T>) {
                    std::ranges::copy(std::string(par), std::back_inserter(_msgBuffer));
                } else if constexpr (traits::mcc_char_range<T>) {
                    std::ranges::copy(std::string(par.begin(), par.end()), std::back_inserter(_msgBuffer));
                } else if constexpr (std::same_as<T, MccCoordPairKind>) {
                    std::ranges::copy(mcc_pairkind2str(par), std::back_inserter(_msgBuffer));
                } else if constexpr (traits::mcc_time_duration_c<T>) {
                    std::forward<decltype(self)>(self)(par.count());
                } else {
                    static_assert(false, "UNSUPPORTED TYPE!!!");
                }

                if constexpr (sizeof...(Ts)) {
                    std::ranges::copy(MCC_COMMPROTO_PARAMPARAM_DELIM_SEQ, std::back_inserter(_msgBuffer));

                    std::forward<decltype(self)>(self)(pars...);
                }
            }(std::forward<PTs>(params)...);

            _params = {_msgBuffer.begin() + _keyword.size() + MCC_COMMPROTO_KEYPARAM_DELIM_SEQ.size(),
                       _msgBuffer.end()};
        }

        return {};
    }

protected:
    size_t _keywordHash{};
    std::string_view _keyword{};
    std::string_view _params{};

    BYTEREPR_T _msgBuffer{};
};



}  // namespace mcc::network