#pragma once



/****************************************************************************************
 *                          ABSTRACT DEVICE COMPONENTS LIBRARY                           *
 ****************************************************************************************/

#include <concepts>
#include <format>
#include <functional>
#include <string>
#include <system_error>
#include <type_traits>
#include <utility>


#include <snipplib/concepts/snplib_traits.h>
#include <snipplib/containers/snplib_hmap.h>
#include <snipplib/serialization/snplib_serialization.h>



#include "adclib_common.h"


namespace adc
{


enum class AdcDeviceErrorCode : int {
    ERROR_OK,
    ERROR_NO_CMD_ID,
    ERROR_NO_ATTR_ID,
    ERROR_RO_ATTR,
    ERROR_WO_ATTR,
    ERROR_ATTR_RANGE,
    ERROR_SERIALIZATION,
    ERROR_DESERIALIZATION,
    ERROR_UNKNOWN
};

}  // namespace adc

namespace std
{

template <>
class is_error_code_enum<adc::AdcDeviceErrorCode> : public true_type
{
};

}  // namespace std


namespace adc
{

// error category

struct AdcDeviceErrorCategory : std::error_category {
    const char* name() const noexcept
    {
        return "ADCLIB-DEVICE-ERR-CATEGORY";
    }

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

        switch (err) {
            case AdcDeviceErrorCode::ERROR_OK:
                return "OK";
            case AdcDeviceErrorCode::ERROR_NO_CMD_ID:
                return "invalid command ID";
            case AdcDeviceErrorCode::ERROR_NO_ATTR_ID:
                return "invalid attribute ID";
            case AdcDeviceErrorCode::ERROR_RO_ATTR:
                return "read-only attribute";
            case AdcDeviceErrorCode::ERROR_WO_ATTR:
                return "write-only attribute";
            case AdcDeviceErrorCode::ERROR_ATTR_RANGE:
                return "value is out of attribute range ";
            case AdcDeviceErrorCode::ERROR_SERIALIZATION:
                return "serialization error";
            case AdcDeviceErrorCode::ERROR_DESERIALIZATION:
                return "deserialization error";
            default:
                return "UNKNOWN";
        }
    }

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

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


template <typename T>
concept adclib_command_exec_t = snplib::snplib_callable_c<T> && (snplib::snplib_func_traits_t<T>::arity == 0) &&
                                std::same_as<adc_error_t, typename snplib::snplib_func_traits_t<T>::ret_t>;

template <typename T>
concept adclib_attr_getter_c = std::same_as<T, std::nullptr_t> || requires(T t) {
    { t() } -> adc_result_c;
};

template <typename T>
concept adclib_attr_setter_c =
    std::same_as<T, std::nullptr_t> || (snplib::snplib_callable_c<T> && (snplib::snplib_func_traits_t<T>::arity >= 1) &&
                                        std::same_as<adc_error_t, typename snplib::snplib_func_traits_t<T>::ret_t>);


// deduce value type from getter and setter
template <adclib_attr_getter_c GT, adclib_attr_setter_c ST>
using adclib_attr_value_deduced_t = std::conditional_t<
    std::is_null_pointer_v<GT>,
    std::conditional_t<std::is_null_pointer_v<ST>, void, std::remove_cvref_t<snplib::snplib_func_arg1_t<ST>>>,
    typename std::invoke_result_t<GT>::value_type>;


template <adclib_attr_getter_c GT, adclib_attr_setter_c ST>
struct adclib_is_deduced_void_t {
    static constexpr bool value = std::is_void_v<adclib_attr_value_deduced_t<GT, ST>>;
};

// conversional function signature:
//     "from": adc_result_t<UT> func(const adc_result_t<VT>&)
//       "to": adc_result_t<VT> func(const adc_result_t<UT>&)
template <typename T, typename VT>
concept adclib_attr_conv_from_func_c =
    std::same_as<T, std::nullptr_t> ||
    (std::invocable<T, const adc_result_t<VT>&> && !std::is_void_v<std::invoke_result_t<T, const adc_result_t<VT>&>>);

template <typename T, typename VT>
concept adclib_attr_conv_to_func_c = std::same_as<T, std::nullptr_t> ||
                                     (snplib::snplib_callable_c<T> && (snplib::snplib_func_traits_t<T>::arity == 1) &&
                                      std::same_as<adc_result_t<VT>, typename snplib::snplib_func_traits_t<T>::ret_t>);

template <typename VT, adclib_attr_conv_from_func_c<VT> CONV_FROM_T, adclib_attr_conv_to_func_c<VT> CONV_TO_T>
using adclib_attr_user_deduced_t =
    std::conditional_t<std::is_null_pointer_v<CONV_FROM_T>,
                       std::conditional_t<std::is_null_pointer_v<CONV_TO_T>,
                                          void,
                                          std::remove_cvref_t<snplib::snplib_func_arg1_t<CONV_TO_T>>>,
                       typename snplib::snplib_func_traits_t<CONV_FROM_T>::ret_t>;



template <std::formattable<char> DEV_ID_T = std::string,
          std::formattable<char> ATTR_ID_T = std::string,
          std::formattable<char> CMD_ID_T = std::string>
class AdcGenericDevice
{
protected:
    template <typename VT>
    using attr_getter_t = std::function<adc_result_t<VT>()>;

    template <typename VT>
    using attr_setter_t = std::function<adc_error_t(VT const&)>;

    typedef std::vector<char> serialized_t;
    typedef std::function<adc_error_t(serialized_t&)> attr_serial_func_t;
    typedef std::function<adc_error_t(serialized_t const&)> attr_deserial_func_t;

    struct attr_t {
        attr_t(AdcGenericDevice& dev, ATTR_ID_T id) : _dev(dev), _id(std::move(id)) {}

        template <typename VT>
        operator adc_result_t<VT>() const
        {
            auto getter = _dev._attrGetter.template get<attr_getter_t<VT>>(_id);
            if (getter) {
                if (getter.value()) {
                    return getter.value()();
                } else {
                    return std::unexpected(AdcDeviceErrorCode::ERROR_WO_ATTR);
                }
            }

            if (getter.error() == snplib::HeterogenMap<ATTR_ID_T>::ERROR_NO_ELEM) {
                return std::unexpected(AdcDeviceErrorCode::ERROR_NO_ATTR_ID);
            }

            // fallback ...
            return std::unexpected(AdcDeviceErrorCode::ERROR_UNKNOWN);
        }

        template <typename VT>
        adc_error_t operator=(VT&& val)
        {
            auto setter = _dev._attrSetter.template get<attr_setter_t<std::remove_cvref_t<VT>>>(_id);
            if (setter) {
                if (setter.value()) {
                    return setter.value()(std::forward<VT>(val));
                } else {
                    return AdcDeviceErrorCode::ERROR_WO_ATTR;
                }
            }

            if (setter.error() == snplib::HeterogenMap<ATTR_ID_T>::ERROR_NO_ELEM) {
                return AdcDeviceErrorCode::ERROR_NO_ATTR_ID;
            }

            // fallback ...
            return AdcDeviceErrorCode::ERROR_UNKNOWN;
        }

    private:
        AdcGenericDevice& _dev;
        ATTR_ID_T _id;
    };

    DEV_ID_T _devId;

    std::unordered_map<CMD_ID_T, std::function<adc_error_t()>> _commands{};
    std::unordered_map<ATTR_ID_T, attr_t> _attrs{};

    snplib::HeterogenMap<ATTR_ID_T> _attrGetter{};
    snplib::HeterogenMap<ATTR_ID_T> _attrSetter{};

public:
    static constexpr std::tuple<bool,
                                char,
                                short,
                                int,
                                long,
                                long long,
                                unsigned char,
                                unsigned short,
                                unsigned int,
                                unsigned long,
                                unsigned long long,
                                float,
                                double,
                                long double>
        arithmetic_types{};

    typedef DEV_ID_T device_id_t;
    typedef ATTR_ID_T attr_id_t;
    typedef CMD_ID_T cmd_id_t;

    enum AttrAccessType { ATTR_ACCESS_RW, ATTR_ACCESS_RO, ATTR_ACCESS_WO };

    AdcGenericDevice(device_id_t id) : _devId(id) {}

    virtual ~AdcGenericDevice() = default;

    device_id_t id() const
    {
        return _devId;
    }

    // template <snplib::snplib_callable_c ET>
    // void addCommand(CMD_ID_T id, ET&& exec_func)
    // {
    //     _commands.emplace(std::move(id), std::forward<ET>(exec_func));
    // }

    template <adclib_command_exec_t ET>
    void addCommand(CMD_ID_T id, ET&& exec_func)
    {
        _commands.emplace(std::move(id), std::forward<ET>(exec_func));
    }

    template <typename GT, typename ST, typename... VTs>
    void addAttr(ATTR_ID_T id, GT&& getter, ST&& setter, std::tuple<VTs...> = std::tuple<>{})
    {
        using v_t = adclib_attr_value_deduced_t<GT, ST>;
        static_assert(!std::is_void_v<v_t>, "Getter and setter cannot be nullptr_t at the same time!");

        if constexpr (!std::is_null_pointer_v<GT> && !std::is_null_pointer_v<ST>) {
            static_assert(std::invocable<ST, v_t const&>, "Invalid setter argument type!");
        }

        _attrGetter.push(id, attr_getter_t<std::remove_cvref_t<GT>>(std::forward<GT>(getter)),
                         std::tuple<attr_getter_t<VTs>...>{});

        _attrSetter.push(id, attr_setter_t<std::remove_cvref_t<ST>>(std::forward<ST>(setter)),
                         std::tuple<attr_setter_t<VTs>...>{});
    }

    template <adclib_attr_getter_c GT, adclib_attr_setter_c ST, typename... FuncTs>
        requires(sizeof...(FuncTs) > 1)
    void addAttr(ATTR_ID_T id, GT&& getter, ST&& setter, FuncTs&&... cnv_pairs)
    {
        static constexpr size_t NFUNCS = sizeof...(FuncTs);

        static_assert(NFUNCS % 2 == 0, "Number of conversional functions must be an even!");

        using v_t = adclib_attr_value_deduced_t<GT, ST>;
        static_assert(!std::is_void_v<v_t>, "Getter and setter cannot be nullptr_t at the same time!");
    }
};


}  // namespace adc