#pragma once

/*                          MOUNT CONTROL COMPONENTS LIBRARY                            */


/*                          A VERY SIMPLE GUIDING MODEL GENERIC IMPLEMENTATION             */


#include "mcc_mount_concepts.h"
#include "mcc_mount_telemetry.h"
#include "mcc_slew_guiding_model_common.h"

namespace mcc
{

enum class MccSimpleGuidingModelErrorCode : int {
    ERROR_OK,
    ERROR_UNSUPPORTED_COORD_PAIR,
    ERROR_IN_PROHIBITED_ZONE,
    ERROR_ASTROM_COMP,
    ERROR_TELEMETRY_DATA,
    ERROR_PEC_COMP,
    ERROR_HARDWARE_SETPOS,
    ERROR_INVALID_CONTEXT_PARAM,
    ERROR_INVALID_THRESH,
    ERROR_INVALID_CORR_RANGE,
    ERROR_GUIDING_STOPPED
};

}  // namespace mcc

namespace std
{

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

}  // namespace std


namespace mcc
{

/*  error category definition  */

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

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

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

        switch (err) {
            case MccSimpleGuidingModelErrorCode::ERROR_OK:
                return "OK";
            case MccSimpleGuidingModelErrorCode::ERROR_UNSUPPORTED_COORD_PAIR:
                return "slew model: unsupported coordinate pair";
            case MccSimpleGuidingModelErrorCode::ERROR_ASTROM_COMP:
                return "guiding model: cannot perform astrometrical computations";
            case MccSimpleGuidingModelErrorCode::ERROR_TELEMETRY_DATA:
                return "guiding model: cannot get telemetry data";
            case MccSimpleGuidingModelErrorCode::ERROR_PEC_COMP:
                return "guiding model: cannot compute PEC corrections";
            case MccSimpleGuidingModelErrorCode::ERROR_HARDWARE_SETPOS:
                return "guiding model: cannot set position";
            case MccSimpleGuidingModelErrorCode::ERROR_INVALID_CONTEXT_PARAM:
                return "guiding model: invalid context parameter";
            case MccSimpleGuidingModelErrorCode::ERROR_INVALID_THRESH:
                return "guiding model: invalid guiding residual threshold";
            case MccSimpleGuidingModelErrorCode::ERROR_INVALID_CORR_RANGE:
                return "guiding model: invalid guiding correction range";
            case MccSimpleGuidingModelErrorCode::ERROR_GUIDING_STOPPED:
                return "guiding model: stopped";
            default:
                return "UNKNOWN";
        }
    }

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


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



/*                  */

class MccCelestialPointTrack final
{
public:
    template <traits::mcc_astrom_engine_c ASTROM_ENGINE_T, traits::mcc_time_duration_c DT>
    MccCelestialPointTrack(ASTROM_ENGINE_T& astrom_engine,
                           typename ASTROM_ENGINE_T::juldate_t start,
                           DT step,
                           size_t Npoints)
    {
        const auto p_astrom_engine = &astrom_engine;

        _compFunc = []() {

        };
    }

private:
    std::function<size_t()> _compFunc;
};

/*                  */


template <traits::mcc_logger_c LoggerT = MccNullLogger>
class MccSimpleGuidingModel : public LoggerT
{
    template <traits::mcc_mount_controls_c T>
    using coord_t = typename decltype(T::astrometryEngine)::coord_t;

public:
    using LoggerT::logDebug;
    using LoggerT::logError;
    using LoggerT::logInfo;
    using LoggerT::logMessage;
    using LoggerT::logWarn;

    typedef std::error_code error_t;


    using guiding_point_t = MccSlewAndGuidingPoint;

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

        init(mount_controls);
    }

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

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


    error_t guiding(guiding_point_t guiding_point) { return _guidingFunc(std::move(guiding_point)); }

    error_t stopGuiding(bool off) { _doCorrection = off; }

    bool inGuiding() { return _doCorrection; }

    error_t stop() { return MccSimpleGuidingModelErrorCode::ERROR_OK; }

protected:
    std::function<error_t(guiding_point_t)> _guidingFunc{};
    std::atomic_bool _doCorrection{true};
    std::atomic_bool _stopRequested{false};



    error_t 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);

        static_assert(std::derived_from<telemetry_t, MccMountTelemetry<astrom_engine_t, pec_t, hardware_t,
                                                                       typename telemetry_t::mount_telemetry_data_t>>,
                      "TELEMETRY CLASS MUST BE A DESCENDANT OF 'MccMountTelemetry' ONE!");

        using tpl_pz_t = decltype(mount_controls.prohibitedZones);

        const auto p_mount_controls = &mount_controls;

        _guidingFunc = [p_mount_controls, this](guiding_point_t guiding_point) {
            _stopRequested = false;

            if (guiding_point.correctionRange[0] >= guiding_point.correctionRange[1]) {
                return MccSimpleGuidingModelErrorCode::ERROR_INVALID_THRESH;
            }

            auto low_corr_limit = guiding_point.correctionRange[0] * guiding_point.correctionRange[0];
            auto high_corr_limit = guiding_point.correctionRange[1] * guiding_point.correctionRange[1];

            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;
            jd_t jd;


            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;


            typename hardware_t::axes_pos_t ax_pos;

            ax_pos.moving_type = hardware_t::hw_moving_type_t::HW_MOVE_GUIDING;

            t_err = telemetry.setTarget(guiding_point);
            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 MccSimpleGuidingModelErrorCode::ERROR_TELEMETRY_DATA;
                }
            }

            std::array<bool, std::tuple_size_v<tpl_pz_t>> in_zone_flag;

            while (true) {
                if (_stopRequested) {
                    // return MccSimpleGuidingModelErrorCode::ERROR_GUIDING_STOPPED;
                    // interpetate stoping as 'no error' exit
                    return MccSimpleGuidingModelErrorCode::ERROR_OK;
                }


                // suspend the thread here until telemetry data is updated
                t_err = telemetry.waitForUpdatedData(t_data, guiding_point.telemetryUpdateTimeout);

                // check prohibited zones ...
                if (mccCheckInZonePZTuple(t_data, p_mount_controls->prohibitedZones, in_zone_flag)) {
                    return MccSimpleGuidingModelErrorCode::ERROR_IN_PROHIBITED_ZONE;
                };


                if (t_err) {
                    std::string err_str = "An error occured while waiting for updated telemetry";
                    if constexpr (std::same_as<decltype(t_err), error_t>) {
                        std::format_to(std::back_inserter(err_str), ": code = {} ({})", t_err.value(), t_err.message());
                        logError(err_str);
                        return t_err;
                    } else {
                        if constexpr (traits::mcc_formattable<decltype(t_err)>) {
                            std::format_to(std::back_inserter(err_str), ": code = {}", t_err.value());
                        }
                        logError(err_str);
                        return MccSimpleGuidingModelErrorCode::ERROR_TELEMETRY_DATA;
                    }
                }

                if (_stopRequested) {
                    // interpetate stoping as 'no error' exit
                    return MccSimpleGuidingModelErrorCode::ERROR_OK;
                }

                // compare t_data with computed coordinates ...
                if (_doCorrection) {
                    auto coord_diff = telemetry.targetToMountDiff();

                    if (coord_diff.r2 < low_corr_limit) {
                        continue;
                    }

                    if (coord_diff.r2 > high_corr_limit) {
                        logWarn(
                            std::format("guiding model: the 'mount-target' square of difference exceeds the limit "
                                        "(diff = {}; lim = {})",
                                        (double)coord_diff.r2, (double)high_corr_limit));
                        continue;
                    }

                    // do correction
                    // current celestial position of target is already computed for current time point
                    // so one needs only correct apparent coordinates for PEC corrections
                    ax_pos.time_point = t_data.time_point;
                    if constexpr (mccIsEquatorialMount(pec_t::mountType)) {
                        ax_pos.x = t_data.tagHA - t_data.pecX;
                        ax_pos.y = t_data.tagDEC - t_data.pecY;
                    } else if constexpr (mccIsAltAzMount(pec_t::mountType)) {
                        ax_pos.x = t_data.tagAZ - t_data.pecX;
                        ax_pos.y = t_data.tagALT - t_data.pecY;
                    } else {
                        static_assert(false, "UNSUPPORTED MOUNT TYPE!");
                    }


                    // asynchronous operation!
                    auto 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 MccSimpleGuidingModelErrorCode::ERROR_HARDWARE_SETPOS;
                        }
                    }
                }
            }

            return MccSimpleGuidingModelErrorCode::ERROR_OK;
        };
    }
};

}  // namespace mcc