#pragma once


/*                          MOUNT CONTROL COMPONENTS LIBRARY                            */


/*                          A VERY SIMPLE SLEW MODEL GENERIC IMPLEMENTATION             */


#include "mcc_mount_concepts.h"

#include "mcc_slew_guiding_model_common.h"

namespace mcc
{

enum class MccSimpleSlewModelErrorCode : int {
    ERROR_OK,
    ERROR_UNSUPPORTED_COORD_PAIR,
    ERROR_IN_PROHIBITED_ZONE,
    ERROR_ASTROM_COMP,
    ERROR_TELEMETRY_DATA,
    ERROR_PEC_COMP,
    ERROR_HARDWARE_SETPOS,
    ERROR_HARDWARE_GETPOS,
    ERROR_SLEW_TIMEOUT
};

}  // namespace mcc

namespace std
{

template <>
class is_error_code_enum<mcc::MccSimpleSlewModelErrorCode> : public true_type
{
};

}  // namespace std


namespace mcc
{


/*  error category definition  */

// error category
struct MccSimpleSlewModelCategory : public std::error_category {
    MccSimpleSlewModelCategory() : std::error_category() {}

    const char* name() const noexcept
    {
        return "ADC_GENERIC_DEVICE";
    }

    std::string message(int ec) const
    {
        MccSimpleSlewModelErrorCode err = static_cast<MccSimpleSlewModelErrorCode>(ec);

        switch (err) {
            case MccSimpleSlewModelErrorCode::ERROR_OK:
                return "OK";
            case MccSimpleSlewModelErrorCode::ERROR_UNSUPPORTED_COORD_PAIR:
                return "slew model: unsupported coordinate pair";
            case MccSimpleSlewModelErrorCode::ERROR_IN_PROHIBITED_ZONE:
                return "slew model: position is in prohibited zone";
            case MccSimpleSlewModelErrorCode::ERROR_ASTROM_COMP:
                return "slew model: cannot perform astrometrical computations";
            case MccSimpleSlewModelErrorCode::ERROR_TELEMETRY_DATA:
                return "slew model: cannot get telemetry data";
            case MccSimpleSlewModelErrorCode::ERROR_PEC_COMP:
                return "slew model: cannot compute PEC corrections";
            case MccSimpleSlewModelErrorCode::ERROR_HARDWARE_SETPOS:
                return "slew model: cannot set position";
            case MccSimpleSlewModelErrorCode::ERROR_HARDWARE_GETPOS:
                return "slew model: cannot get position";
            default:
                return "UNKNOWN";
        }
    }

    static const MccSimpleSlewModelCategory& get()
    {
        static const MccSimpleSlewModelCategory constInst;
        return constInst;
    }
};


inline std::error_code make_error_code(MccSimpleSlewModelErrorCode ec)
{
    return std::error_code(static_cast<int>(ec), MccSimpleSlewModelCategory::get());
}


/*
 *   WARNING: it is assumed that coordinates are in radians!
 *            but this fact is only used if slew coordinate pair are given as
 *            [azimuth, zenithal distance] (see sources code below)
 */

template <traits::mcc_logger_c LoggerT = MccNullLogger>
class MccSimpleSlewModel : public LoggerT
{
public:
    using LoggerT::logDebug;
    using LoggerT::logError;
    using LoggerT::logInfo;
    using LoggerT::logMessage;
    using LoggerT::logWarn;

    typedef std::error_code error_t;

    struct slew_point_t : MccCelestialPoint {
        // target-mount coordinate difference to start adjusting slewing (in radians)
        coord_t adjustCoordDiff{(double)MccAngle{10.0_degs}};

        // coordinates difference to stop slewing (in radians)
        coord_t slewPrecision{(double)MccAngle{5.0_arcsecs}};

        // coordinates polling interval in seconds
        std::chrono::duration<double> coordPollingInterval{0.1};
        bool stopAfterSlew{false};
        std::chrono::seconds timeout{3600};
    };


    template <traits::mcc_mount_controls_c MOUNT_CONTROLS_T, typename... LoggerCtorArgTs>
    MccSimpleSlewModel(MOUNT_CONTROLS_T& mount_controls, LoggerCtorArgTs&&... ctor_args)
        requires(!std::same_as<LoggerT, MccNullLogger>)
        : LoggerT(std::forward<LoggerCtorArgTs>(ctor_args)...)
    {
        logDebug(std::format("Create 'MccSimpleSlewModel' class instance ({})", (void*)this));

        init(mount_controls);
    }

    template <traits::mcc_mount_controls_c MOUNT_CONTROLS_T>
    MccSimpleSlewModel(MOUNT_CONTROLS_T& mount_controls)
        requires(std::same_as<LoggerT, MccNullLogger>)
    {
        init(mount_controls);
    }

    virtual ~MccSimpleSlewModel()
    {
        logDebug(std::format("Delete 'MccSimpleSlewModel' class instance ({})", (void*)this));
    }

    error_t slew(slew_point_t pars)
    {
        error_t res_err = _slewFunc(std::move(pars));

        return res_err;
    }

protected:
    std::function<error_t(const slew_point_t&)> _slewFunc{};

    void init(auto& mount_controls)
    {
        // deduce controls types
        using astrom_engine_t = decltype(mount_controls.astrometryEngine);
        using hardware_t = decltype(mount_controls.hardware);
        using pec_t = decltype(mount_controls.PEC);
        using telemetry_t = decltype(mount_controls.telemetry);
        using tpl_pz_t = decltype(mount_controls.prohibitedZones);

        static constexpr size_t Nzones = std::tuple_size_v<tpl_pz_t>;

        const auto p_mount_controls = &mount_controls;


        _slewFunc = [p_mount_controls](this auto&& self, slew_point_t slew_point) {
            auto& astrom_engine = p_mount_controls->astrometryEngine;
            auto& hardware = p_mount_controls->hardware;
            auto& pec = p_mount_controls->PEC;
            auto& telemetry = p_mount_controls->telemetry;

            using coord_t = typename astrom_engine_t::coord_t;
            using jd_t = typename astrom_engine_t::juldate_t;

            typename hardware_t::axes_pos_t ax_pos;

            error_t res_err;
            typename astrom_engine_t::error_t ast_err;
            typename pec_t::error_t pec_err;

            typename telemetry_t::error_t t_err;
            typename telemetry_t::mount_telemetry_data_t t_data;

            coord_t ra_icrs, dec_icrs;


            if (slew_point.coordPairKind == mcc::MccCoordPairKind::COORDS_KIND_XY) {
                // the pair is interpretated as raw encoder coordinates
                if (slew_point.stopAfterSlew) {
                    ax_pos.x = slew_point.x;
                    ax_pos.y = slew_point.y;
                } else {  // very strange but should be processed! forward to compute ICRS RA AND DEC
                    typename pec_t::pec_result_t pec_res;

                    pec_err = pec->compute(slew_point.x, slew_point.y, pec_res);
                    if (!pec_err) {
                        slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_XY;
                        slew_point.x += pec_res.dx;
                        slew_point.y += pec_res.dy;

                        res_err = self(std::move(slew_point));
                    }
                }

            } else if (slew_point.coordPairKind ==
                       mcc::MccCoordPairKind::COORDS_KIND_RADEC_ICRS) {  // catalog coordinates
                if (slew_point.stopAfterSlew) {
                    jd_t jd;
                    coord_t ra_app, dec_app, ha, az, alt;
                    typename astrom_engine_t::eo_t eo;

                    logDebug("Input slew coordinates are ICRS RA-DEC: convert it to apparent ...");


                    ast_err = astrom_engine->greg2jul(astrom_engine_t::timePointNow(), jd);

                    if (!ast_err) {
                        ast_err =
                            astrom_engine->icrs2obs(slew_point.x, slew_point.y, jd, ra_app, dec_app, ha, az, alt, eo);

                        if (!ast_err) {
                            if constexpr (mccIsEquatorialMount(pec_t::mountType)) {
                                slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_HADEC_APP;
                                slew_point.x = ha;
                                slew_point.y = dec_app;

                                res_err = self(std::move(slew_point));
                            } else if constexpr (mccIsAltAzMount(pec_t::mountType)) {
                                slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_AZALT;
                                slew_point.x = az;
                                slew_point.y = alt;

                                res_err = self(std::move(slew_point));
                            } else {
                                static_assert(false, "UNKNOWN MOUNT TYPE!");
                            }
                        }
                    }
                } else {  // OK, here one should stop with coordinates converting
                    ra_icrs = slew_point.x;
                    dec_icrs = slew_point.y;
                }

            } else if (slew_point.coordPairKind == mcc::MccCoordPairKind::COORDS_KIND_RADEC_APP) {  // apparent
                if (slew_point.stopAfterSlew) {
                    jd_t jd;
                    typename astrom_engine_t::eo_t eo;

                    logDebug("Input slew coordinates are apparent RA-DEC: convert it to apparent HA-DEC ...");

                    ast_err = astrom_engine->greg2jul(astrom_engine_t::timePointNow(), jd);
                    if (!ast_err) {
                        typename astrom_engine_t::sideral_time_t lst;
                        ast_err = astrom_engine->apparentSiderTime(jd, lst, true);

                        if (!ast_err) {
                            ast_err = astrom_engine->eqOrigins(jd, eo);
                            if (!ast_err) {
                                slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_HADEC_APP;
                                slew_point.x = lst - slew_point.x + eo;  // HA = LST - RA_APP + EO

                                res_err = self(std::move(slew_point));
                            }
                        }
                    }
                }
            } else if (slew_point.coordPairKind == mcc::MccCoordPairKind::COORDS_KIND_HADEC_APP) {  // apparent
                if (slew_point.stopAfterSlew) {
                    if constexpr (mccIsEquatorialMount(pec_t::mountType)) {  // compute encoder coordinates
                        logDebug("Input slew coordinates are apparent HA-DEC: convert it to hardware encoder ones ...");

                        coord_t eps = 1.0 / 3600.0 * std::numbers::pi / 180.0;

                        typename pec_t::pec_result_t pec_res;

                        // pec_err = pec->reverseCompute(slew_point.x, slew_point.y, pec_res, context.eps,
                        // context.maxIter);
                        pec_err = pec->compute(slew_point.x, slew_point.y, pec_res);
                        if (!pec_err) {
                            slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_XY;
                            slew_point.x -= pec_res.dx;
                            slew_point.y -= pec_res.dy;

                            res_err = self(std::move(slew_point));
                        }
                    } else if constexpr (mccIsAltAzMount(pec_t::mountType)) {
                        coord_t az, alt;

                        logDebug("Input slew coordinates are apparent HA-DEC: convert it to AZ-ALT ...");

                        ast_err = astrom_engine->hadec2azalt(slew_point.x, slew_point.y, az, alt);

                        if (!ast_err) {
                            slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_AZALT;
                            slew_point.x = az;
                            slew_point.y = alt;

                            res_err = self(std::move(slew_point));
                        }
                    } else {
                        static_assert(false, "UNKNOWN MOUNT TYPE!");
                    }
                }
            } else if (slew_point.coordPairKind == mcc::MccCoordPairKind::COORDS_KIND_AZALT) {
                if (slew_point.stopAfterSlew) {
                    if constexpr (mccIsEquatorialMount(pec_t::mountType)) {
                        coord_t ha, dec;

                        logDebug("Input slew coordinates are AZ-ALT: convert it to HA-DEC ...");

                        ast_err = astrom_engine->azalt2hadec(slew_point.x, slew_point.y, ha, dec);

                        if (!ast_err) {
                            slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_HADEC_APP;
                            slew_point.x = ha;
                            slew_point.y = dec;

                            res_err = self(std::move(slew_point));
                        }
                    } else if constexpr (mccIsAltAzMount(pec_t::mountType)) {  // compute encoder coordinates
                        coord_t eps = 1.0 / 3600.0 * std::numbers::pi / 180.0;

                        logDebug("Input slew coordinates are AZ-ALT: convert it to hardware encoder ones ...");

                        typename pec_t::pec_result_t pec_res;

                        // pec_err = pec->reverseCompute(slew_point.x, slew_point.y, pec_res, context.eps,
                        // context.maxIter);
                        pec_err = pec->compute(slew_point.x, slew_point.y, pec_res);
                        if (!pec_err) {
                            slew_point.coordPairKind = mcc::MccCoordPairKind::COORDS_KIND_XY;
                            slew_point.x -= pec_res.dx;
                            slew_point.y -= pec_res.dy;

                            res_err = self(std::move(slew_point));
                        }

                    } else {
                        static_assert(false, "UNKNOWN MOUNT TYPE!");
                    }
                }
            } else if (slew_point.coordPairKind == mcc::MccCoordPairKind::COORDS_KIND_AZZD) {
                //
                // WARNING: it is assumed that coordinates are in radians!
                //
                logDebug("Input slew coordinates are AZ-ZD: convert it to AZ-ALT ...");

                slew_point.y = std::numbers::pi / 2.0 - slew_point.y;

                res_err = self(std::move(slew_point));
            } else {
                return MccSimpleSlewModelErrorCode::ERROR_UNSUPPORTED_COORD_PAIR;
            }

            if (res_err) {
                return res_err;
            }

            if (pec_err) {
                if constexpr (std::same_as<decltype(pec_err), error_t>) {
                    logError(std::format("An PEC error occured: code = {} ({})", pec_err.value(), pec_err.message()));
                    return pec_err;
                } else {
                    if constexpr (traits::mcc_formattable<decltype(pec_err)>) {
                        logError(std::format("An PEC error occured: code = {}", pec_err));
                    }
                    return MccSimpleSlewModelErrorCode::ERROR_PEC_COMP;
                }
            }

            if (ast_err) {
                if constexpr (std::same_as<decltype(ast_err), error_t>) {
                    logError(std::format("An error occured while performing astrometry computations: code = {} ({})",
                                         ast_err.value(), ast_err.message()));
                    return ast_err;
                } else {
                    if constexpr (traits::mcc_formattable<decltype(ast_err)>) {
                        logError(std::format("An error occured while performing astrometry computations: code = {}",
                                             ast_err));
                    }
                    return MccSimpleSlewModelErrorCode::ERROR_ASTROM_COMP;
                }
            }

            // compute ICRS RA and DEC if needed
            if (!slew_point.stopAfterSlew) {
                if (slew_point.coordPairKind != mcc::MccCoordPairKind::COORDS_KIND_RADEC_ICRS) {
                    jd_t jd;
                    ast_err = astrom_engine.greg2jul(astrom_engine_t::timePointNow(), jd);
                    if (!ast_err) {
                        ast_err = astrom_engine.obs2icrs(slew_point.coordPairKind, slew_point.x, slew_point.y, jd,
                                                         ra_icrs, dec_icrs);
                    }

                    if (ast_err) {
                        if constexpr (std::same_as<decltype(ast_err), error_t>) {
                            logError(
                                std::format("An error occured while performing astrometry computations: code = {} ({})",
                                            ast_err.value(), ast_err.message()));
                            return ast_err;
                        } else {
                            if constexpr (traits::mcc_formattable<decltype(ast_err)>) {
                                logError(std::format(
                                    "An error occured while performing astrometry computations: code = {}", ast_err));
                            }
                            return MccSimpleSlewModelErrorCode::ERROR_ASTROM_COMP;
                        }
                    }
                }
            }


            // move mount (it is assumed this is asynchronous operation!!!)
            typename hardware_t::error_t err = hardware->setPos(ax_pos);

            if (err) {
                if constexpr (std::same_as<decltype(err), error_t>) {
                    logError(std::format("An hardware error occured: code = {} ({})", err.value(), err.message()));
                    return err;
                } else {
                    if constexpr (traits::mcc_formattable<decltype(err)>) {
                        logError(std::format("An hardware error occured: code = {}", err));
                    }
                    return MccSimpleSlewModelErrorCode::ERROR_HARDWARE_SETPOS;
                }
            }

            size_t i_iter = 0;


            typename hardware_t::axes_pos_t::time_point_t prev_time_point{};
            // typename telemetry_t::mount_telemetry_data_t::time_point_t prev_time_point{};
            typename telemetry_t::mount_telemetry_data_t::coord_t xr, yr, coord_diff2,
                adjRad2 = slew_point.adjustCoordDiff * slew_point.adjustCoordDiff;

            std::array<bool, Nzones> in_zone_flag;
            auto start_poll_tm = std::chrono::steady_clock::now();


            while (true) {
                // check prohibited zones

                t_err = mccCheckInZonePZTuple(*telemetry, p_mount_controls->prohibitedZones, in_zone_flag);

                // it is assumed here that telemetry data is in actual state!
                // t_err = telemetry.data(t_data);
                if (t_err) {
                    if constexpr (std::same_as<decltype(t_err), error_t>) {
                        logError(
                            std::format("An telemetry error occured: code = {} ({})", t_err.value(), t_err.message()));
                        return t_err;
                    } else {
                        if constexpr (traits::mcc_formattable<decltype(t_err)>) {
                            logError(std::format("An telemetry error occured: code = {}", t_err));
                        }
                        return MccSimpleSlewModelErrorCode::ERROR_TELEMETRY_DATA;
                    }
                }

                err = hardware->getPos(ax_pos);

                if (err) {
                    if constexpr (std::same_as<decltype(err), error_t>) {
                        logError(std::format("An hardware error occured: code = {} ({})", err.value(), err.message()));
                        return err;
                    } else {
                        if constexpr (traits::mcc_formattable<decltype(err)>) {
                            logError(std::format("An hardware error occured: code = {}", err));
                        }
                        return MccSimpleSlewModelErrorCode::ERROR_HARDWARE_GETPOS;
                    }
                }

                if constexpr (mccIsEquatorialMount(pec_t::mountType)) {
                    xr = slew_point.x - t_data.mntHA;
                    yr = slew_point.y - t_data.mntDEC;
                } else if constexpr (mccIsAltAzMount(pec_t::mountType)) {
                    xr = slew_point.x - t_data.mntAZ;
                    yr = slew_point.y - t_data.mntALT;
                } else {
                    static_assert(false, "UNSUPPORTED MOUNT TYPE!");
                }

                coord_diff2 = xr * xr + yr * yr;

                if (coord_diff2 < adjRad2) {  // switch to adjusting mode
                }

                // if (prev_time_point == t_data.time_point) {
                if (prev_time_point == ax_pos.time_point) {
                    continue;
                }

                if (slew_point.stopAfterSlew) {  // slew and stop, so mount moving rate must be 0 at the end
                    if (ax_pos.state == hardware_t::hw_state_t::HW_STATE_STOP) {
                        break;
                    }
                    // mount_rate2 = t_data.mntRateX * t_data.mntRateX + t_data.mntRateY * t_data.mntRateY;

                    // if (utils::isEqual((double)mount_rate2, 0.0)) {
                    //     ++i_iter;
                    // } else {
                    //     i_iter = 0;
                    // }
                } else {  // slew and guiding, so mount rate must be near tracking rate at the end
                    if (ax_pos.state == hardware_t::hw_state_t::HW_STATE_TRACK) {
                        break;
                    }
                    // xrate = t_data.mntRateX - context.guidingRateX;
                    // yrate = t_data.mntRateY - context.guidingRateY;
                    // mount_rate2 = xrate * xrate + yrate * yrate;

                    // if (mount_rate2 <= context.guidingRateEps) {
                    //     ++i_iter;
                    // } else {
                    //     i_iter = 0;
                    // }
                }

                // if (i_iter >= context.maxRateCycles) {
                //     break;
                // }

                prev_time_point = t_data.time_point;

                if ((std::chrono::steady_clock::now() - start_poll_tm) > slew_point.timeout) {
                    logError("Waiting time for completion of slewing expired!");
                    return MccSimpleSlewModelErrorCode::ERROR_SLEW_TIMEOUT;
                }
            }


            return MccSimpleSlewModelErrorCode::ERROR_OK;
        };
    }
};


// static_assert(traits::mcc_slew_model_c<>);

}  // namespace mcc