#pragma once

/*  MOUNT CONTROL COMPONENTS LIBRARY  */

#include <atomic>
#include <chrono>
#include <concepts>
#include <cstdint>
#include <fstream>
#include <functional>
#include <string_view>
#include "spdlog/sinks/null_sink.h"

#include "mcc_spdlog.h"
#include "mount_astrom.h"
#include "mount_astrom_default.h"

// low-level functions
namespace lowlevel
{
#include "../LibSidServo/sidservo.h"
}  // namespace lowlevel



namespace mcc
{

namespace traits
{

// mount state type concept
template <typename T>
concept mcc_mount_state_c = requires(T t, const T t_const) {
    { t_const.ident() } -> std::same_as<std::string_view>;

    { t.enter() } -> std::same_as<void>;
    { t.exit() } -> std::same_as<void>;
};

}  // namespace traits


/*   SOME BASIC DATA STRUCTURES DEFINITIONS  */

// meteo parameters (e.g. to compute refraction)
struct MccMountMeteo {
    typedef double temp_t;
    typedef double humid_t;
    typedef double press_t;

    temp_t temperature;  // Temperature in C
    humid_t humidity;    // humidity in %
    press_t pressure;    // atmospheric presure in hPa=mB
};

// mount current position and related quantities
struct MccMountPosition {
    typedef double mnt_coord_t;
    typedef double mnt_speed_t;
    typedef double time_point_t;

    // time-related
    std::chrono::system_clock::time_point utc;
    time_point_t mjd;  // modified Julian date
    time_point_t ut1;
    time_point_t tt;
    time_point_t siderTime;  // sideral time (in radians)

    // apparent target (user-input) current coordinates (in radians)
    mnt_coord_t tagRA, tagDEC;
    mnt_coord_t tagHA;
    mnt_coord_t tagAZ, tagZD;

    // encoder-measured current mount coordinates (in radians)
    mnt_coord_t mntRA, mntDEC;
    mnt_coord_t mntHA;
    mnt_coord_t mntAZ, mntZD;

    // encoder-measured current mount moving speed (in radians/s)
    mnt_speed_t mntSpeedX,
        mntSpeedY;  // X - HA, Y - DEC for equatorial-type mount; X - AZ, Y - ZD for horizontal-type one

    // current refraction coefficient
    mnt_coord_t currRefr;

    // PCS (pointing correction system) corrections
    mnt_coord_t pcsX, pcsY;  // X - HA, Y - DEC for equatorial-type mount; X - AZ, Y - ZD for horizontal-type one
};


/*   MOUNT BASE TEMPLATED CLASS WITH BASIC FUNCTIONALITY   */

enum class MccMountType : uint8_t { GERMAN_TYPE, FORK_TYPE, CROSSAXIS_TYPE, ALTAZ_TYPE };

// implements a Finite State Machine Pattern
template <MccMountType MOUNT_TYPE>
class MccMount : public utils::MccSpdlogLogger
{
    typedef double mnt_coord_t;
    typedef double mnt_speed_t;
    typedef double time_point_t;

public:
    static constexpr MccMountType mountType = MOUNT_TYPE;

    /*  mount main-cycle variable quantities (mount orientation)  */
    struct mount_orient_t {
        // time-related
        std::chrono::system_clock::time_point utc;
        time_point_t mjd;        // modified Julian date
        time_point_t siderTime;  // sideral time (in radians)

        // apparent target (user-input) current coordinates (in radians)
        mnt_coord_t tagRA, tagDEC;
        mnt_coord_t tagHA;
        mnt_coord_t tagAZ, tagZD;

        // encoder-measured current mount coordinates (in radians)
        mnt_coord_t mntRA, mntDEC;
        mnt_coord_t mntHA;
        mnt_coord_t mntAZ, mntZD;

        // encoder-measured current mount moving speed (in radians/s)
        mnt_speed_t mntSpeedX,
            mntSpeedY;  // X - HA, Y - DEC for equatorial-type mount; X - AZ, Y - ZD for horizontal-type one

        // current refraction coefficient
        mnt_coord_t currRefr;

        // PCS (pointing correction system) corrections
        mnt_coord_t pcsX, pcsY;  // X - HA, Y - DEC for equatorial-type mount; X - AZ, Y - ZD for horizontal-type one

        // mount current state
    };


    struct mount_config_t {
        std::string leap_seconds_filename{};  // empty to use hardcoded default value!
        std::string earth_orient_filename{};  // empty to use hardcoded default value!
    };


    /*  Constructors and destructor  */

    MccMount(traits::mcc_input_char_range auto const& logger_mark = "[MOUNT]",
             std::shared_ptr<spdlog::logger> logger = spdlog::null_logger_mt("NULL"))
        : utils::MccSpdlogLogger(logger), _exitCurrentState([]() {})
    {
        std::istringstream strst;

        addMarkToPatternIdx(logger_mark);

        logDebug("Create MccMount class instance: thread = {}", getThreadId());


        logInfo("Load leap seconds and Earth orientation databases ...");

        auto time_db_loader = [this](const std::string& filename, std::string_view type, auto& db) {
            if (filename.empty()) {
                logWarn("An empty {} filename! Skip and keep default values!", type);
                return;
            }

            bool ok = db.load(filename);
            if (!ok) {
                logError("CANNOT parse {} file '{}' or it is not accessable!", type, filename);
                logWarn("Keep {} database in default state!", type);
            } else {
                logInfo("{} database was successfully loaded from '{}' file", type, filename);
            }
        };

        time_db_loader(_mountCurrentConfig.leap_seconds_filename, "leap seconds", _leapSecondsDB);
        time_db_loader(_mountCurrentConfig.earth_orient_filename, "Earth orientation", _earthOrientDB);
    }

    virtual ~MccMount()
    {
        logDebug("Delete MccMount class instance: thread = {}", getThreadId());
    }


    /*  Public methods  */

    template <traits::mcc_mount_state_c StateT>
    void setMountState(StateT& state)
    {
        _exitCurrentState();  // exit from current state
        _exitCurrentState = [&state]() { state.exit(); };

        state.enter();
    }


    mount_orient_t getMountData() const noexcept
    {
        return _currentMountOrient.load();
    }



    void setMeteo(std::derived_from<MccMountMeteo> auto const& meteo)
    {
        _currentMeteo.store(meteo);
    }

protected:
    mount_config_t _mountCurrentConfig;

    // std::shared_ptr<spdlog::logger> _mountLogger;
    std::function<void()> _exitCurrentState;

    // time scales related databases
    astrom::MccLeapSeconds _leapSecondsDB;
    astrom::MccIersBulletinA _earthOrientDB;

    std::atomic<mount_orient_t> _currentMountOrient;

    std::atomic<MccMountMeteo> _currentMeteo;
};

}  // namespace mcc