ADC/device/adc_device_attribute.h

#pragma once

/*

 ABSTRACT DEVICE COMPONENTS LIBRARY

 */

#include <system_error>
#include <unordered_map>

#include "../common/adc_traits.h"
#include "../common/adc_utils.h"

// #include "../common/adc_value.h"


namespace adc
{

namespace constants
{

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>
    AdcDefaultTrivialConvTypes{};

}  // namespace constants

namespace traits
{

/*    concepts    */

// attribute setter concept
template <typename T>
concept adc_attr_getter_c = std::is_null_pointer_v<T> ||
                            (traits::adc_func_traits<T>::arity == 0 && !std::same_as<traits::adc_retval_t<T>, void>);


// attribute setter concept
template <typename T>
concept adc_attr_setter_c = std::is_null_pointer_v<T> || (traits::adc_func_traits<T>::arity == 1);


// internal-to-user and user-to-internal type conversional function concept
template <typename T>
concept adc_attr_convfunc_c = std::is_null_pointer_v<T> ||
                              (traits::adc_func_traits<T>::arity == 1 && !std::same_as<traits::adc_retval_t<T>, void>);


// deduce attribute type from getter and setter functions signatures
template <adc_attr_getter_c GT, adc_attr_setter_c ST>
using attr_value_t = std::decay_t<
    std::conditional_t<std::is_null_pointer_v<GT>,
                       std::conditional_t<std::is_null_pointer_v<ST>, std::nullptr_t, traits::adc_func_arg1_t<ST>>,
                       traits::adc_retval_t<GT>>>;



// deduce attribute internal type from conversional functions signatures
template <adc_attr_convfunc_c FromFuncT, adc_attr_convfunc_c ToFuncT>
using attr_internal_t = std::decay_t<std::conditional_t<
    std::is_null_pointer_v<ToFuncT>,
    std::conditional_t<std::is_null_pointer_v<FromFuncT>, std::nullptr_t, traits::adc_retval_t<FromFuncT>>,
    traits::adc_retval_t<ToFuncT>>>;


// deduce user-defined type from conversional functions signatures
template <adc_attr_convfunc_c FromFuncT, adc_attr_convfunc_c ToFuncT>
using attr_user_t = std::decay_t<std::conditional_t<
    std::is_null_pointer_v<FromFuncT>,
    std::conditional_t<std::is_null_pointer_v<ToFuncT>, std::nullptr_t, traits::adc_retval_t<ToFuncT>>,
    traits::adc_retval_t<FromFuncT>>>;


// attribute serializer function concept
template <typename T, typename VT>
concept adc_serializer_c =
    std::is_null_pointer_v<T> || (std::invocable<T, const VT&> && !std::same_as<void, traits::adc_retval_t<T>>);


// attribute deserializer function concept
template <typename T, typename VT>
concept adc_deserializer_c = std::is_null_pointer_v<T> || (traits::adc_func_traits<T>::arity == 1 &&
                                                           std::convertible_to<traits::adc_retval_t<T>, VT>);


template <typename SRT, typename DSRT>
using adc_attr_serialized_t = std::decay_t<
    std::conditional_t<std::is_null_pointer_v<SRT>,
                       std::conditional_t<std::is_null_pointer_v<DSRT>, std::nullptr_t, traits::adc_func_arg1_t<DSRT>>,
                       traits::adc_retval_t<SRT>>>;


}  // namespace traits

// error codes
enum class AdcDeviceAttributeErrorCode : int {
    ERROR_OK,
    ERROR_NO_CONV_FUNC,
    ERROR_INTERNAL_TYPE_MISMATCH,
    ERROR_READ_ONLY,
    ERROR_WRITE_ONLY,
    ERROR_INVALID_SERIALIZED_TYPE,
    ERROR_NO_SERIALIZER,
    ERROR_NO_DESERIALIZER
};

}  // namespace adc


namespace std
{

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

}  // namespace std



namespace adc
{

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

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

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

        switch (err) {
            case AdcDeviceAttributeErrorCode::ERROR_OK:
                return "OK";
            case AdcDeviceAttributeErrorCode::ERROR_NO_CONV_FUNC:
                return "conversion function is not defined";
            case AdcDeviceAttributeErrorCode::ERROR_INTERNAL_TYPE_MISMATCH:
                return "try to setup default conversion function for invalid type (internal type mismatch)";
            case AdcDeviceAttributeErrorCode::ERROR_READ_ONLY:
                return "device attribute is read-only";
            case AdcDeviceAttributeErrorCode::ERROR_WRITE_ONLY:
                return "device attribute is write-only";
            case AdcDeviceAttributeErrorCode::ERROR_INVALID_SERIALIZED_TYPE:
                return "invalid user-passed serialized type";
            case AdcDeviceAttributeErrorCode::ERROR_NO_SERIALIZER:
                return "serializing function was not defined";
            case AdcDeviceAttributeErrorCode::ERROR_NO_DESERIALIZER:
                return "deserializing function was not defined";
            default:
                return "UNKNOWN";
        }
    }

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


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



template <typename IdentT = std::string, typename SerializedT = std::vector<char>>
class AdcDeviceAttribute
{
    static_assert(!std::is_null_pointer_v<SerializedT>, "Deduced serialized type must not be std::nullptr_t!!!");

protected:
    template <typename T>
    using ret_value_t = std::decay_t<traits::adc_retval_t<T>>;

    template <typename VT>
    inline static std::unordered_map<const AdcDeviceAttribute*, std::function<VT()>> _getterFunc{};

    template <typename VT>
    inline static std::unordered_map<const AdcDeviceAttribute*, std::function<void(const VT&)>> _setterFunc{};

    std::function<SerializedT()> _serializerFunc;

    std::function<void(const SerializedT&)> _deserializerFunc;

    std::function<void()> _clearFunc;

    std::function<void(AdcDeviceAttribute*)> _copyFunc;
    std::function<void(AdcDeviceAttribute*)> _moveFunc;


    template <typename VT>
    struct ValueHolder {
        std::function<VT()> _getterFunc;
        std::function<void(const VT&)> _setterFunc;

        // std::unordered_map<const AdcDeviceAttribute*>
    };

public:
    typedef IdentT ident_t;

    typedef SerializedT serialized_t;

    enum AccessType { ReadOnly, WriteOnly, ReadWrite };


    /*  CONSTRUCTORS AND DESTRUCTOR  */

    template <traits::adc_attr_getter_c GT,
              traits::adc_attr_setter_c ST,
              typename ValueT = traits::attr_value_t<GT, ST>,
              traits::adc_serializer_c<ValueT> SRT =
                  decltype(utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>),
              traits::adc_deserializer_c<ValueT> DSRT =
                  decltype(utils::AdcDefaultValueConverter<>::deserialize<ValueT, serialized_t>)>
    AdcDeviceAttribute(const IdentT& ident,
                       GT&& getter,
                       ST&& setter,
                       SRT&& serializer = utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>,
                       DSRT&& deserializer = utils::AdcDefaultValueConverter<>::deserialize<ValueT, serialized_t>)
        : _ident(ident), _accessType(AdcDeviceAttribute::ReadWrite)
    {
        static_assert(!std::is_null_pointer_v<ValueT>, "Getter and Setter can not be nullptr simultaneously!!!");


        _getterFunc<ValueT>.emplace(this, std::forward<GT>(getter));
        _setterFunc<ValueT>.emplace(this, std::forward<ST>(setter));

        if constexpr (std::is_null_pointer_v<GT>) {
            _accessType = AdcDeviceAttribute::WriteOnly;
        }

        if constexpr (std::is_null_pointer_v<ST>) {
            _accessType = AdcDeviceAttribute::ReadOnly;
        }

        if constexpr (!std::is_null_pointer_v<GT> && !std::is_null_pointer_v<SRT>) {
            _serializerFunc = [wrapper = traits::adc_pf_wrapper(std::forward<SRT>(serializer)), this]() {
                auto& serializer = std::get<0>(wrapper);


                auto val = _getterFunc<ValueT>[this]();

                return serializer(val);
            };
        }


        if constexpr (!std::is_null_pointer_v<ST> && !std::is_null_pointer_v<DSRT>) {
            _deserializerFunc = [wrapper = traits::adc_pf_wrapper(std::forward<DSRT>(deserializer)),
                                 this](const SerializedT& sval) {
                auto& deserializer = std::get<0>(wrapper);

                ValueT val = deserializer(sval);

                _setterFunc<ValueT>[this](val);
            };
        }

        _clearFunc = [this]() {
            _getterFunc<ValueT>.erase(this);
            _setterFunc<ValueT>.erase(this);
        };


        // copy TO other
        _copyFunc = [this](AdcDeviceAttribute* other) {
            _getterFunc<ValueT>.emplace(other, _getterFunc<ValueT>[this]);
            _setterFunc<ValueT>.emplace(other, _setterFunc<ValueT>[this]);

            // define copy-function for newly constructed object
            other->_copyFunc = [other](AdcDeviceAttribute* o_next) {
                _getterFunc<ValueT>.emplace(o_next, _getterFunc<ValueT>[other]);
                _setterFunc<ValueT>.emplace(o_next, _setterFunc<ValueT>[other]);
            };
        };


        // move TO other
        _moveFunc = [this](AdcDeviceAttribute* other) {
            _getterFunc<ValueT>.emplace(other, std::move(_getterFunc<ValueT>[this]));
            _setterFunc<ValueT>.emplace(other, std::move(_setterFunc<ValueT>[this]));

            // define move-function for newly constructed object
            other->_moveFunc = [other](AdcDeviceAttribute* o_next) {
                _getterFunc<ValueT>.emplace(o_next, std::move(_getterFunc<ValueT>[other]));
                _setterFunc<ValueT>.emplace(o_next, std::move(_setterFunc<ValueT>[other]));
            };
        };
    }


    template <traits::adc_tuple_like TupleT,
              traits::adc_attr_getter_c GT,
              traits::adc_attr_setter_c ST,
              typename ValueT = traits::attr_value_t<GT, ST>,
              traits::adc_serializer_c<ValueT> SRT =
                  decltype(utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>),
              traits::adc_deserializer_c<ValueT> DSRT =
                  decltype(utils::AdcDefaultValueConverter<>::deserialize<ValueT, serialized_t>)>
    AdcDeviceAttribute(const IdentT& ident,
                       TupleT&&,
                       GT&& getter,
                       ST&& setter,
                       SRT&& serializer = utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>,
                       DSRT&& deserializer = utils::AdcDefaultValueConverter<>::deserialize<ValueT, serialized_t>)
        : AdcDeviceAttribute(ident,
                             std::forward<GT>(getter),
                             std::forward<ST>(setter),
                             std::forward<SRT>(serializer),
                             std::forward<DSRT>(deserializer))
    {
        static_assert(!std::is_null_pointer_v<ValueT>, "Getter and Setter can not be nullptr simultaneously!!!");

        AdcDeviceAttribute::setupTrivialConvertFunc<ValueT, std::decay_t<TupleT>>();
    }


    // read-only attribute constructor
    template <std::invocable GT,
              typename ValueT = ret_value_t<GT>,
              traits::adc_serializer_c<ValueT> SRT =
                  decltype(utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>)>
    AdcDeviceAttribute(const IdentT& ident,
                       GT&& getter,
                       SRT&& serializer = utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>)
        : AdcDeviceAttribute(ident, std::forward<GT>(getter), nullptr, std::forward<SRT>(serializer), nullptr)
    {
    }


    template <traits::adc_tuple_like TupleT,
              std::invocable GT,
              typename ValueT = ret_value_t<GT>,
              traits::adc_serializer_c<ValueT> SRT =
                  decltype(utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>)>
    AdcDeviceAttribute(const IdentT& ident,
                       TupleT&&,
                       GT&& getter,
                       SRT&& serializer = utils::AdcDefaultValueConverter<>::serialize<serialized_t, ValueT>)
        : AdcDeviceAttribute(ident, TupleT{}, std::forward<GT>(getter), nullptr, std::forward<SRT>(serializer), nullptr)
    {
    }


    // write-only attribute constructor
    template <traits::adc_attr_setter_c ST,
              typename ValueT = std::decay_t<traits::adc_func_arg1_t<ST>>,
              typename DSRT = decltype(utils::AdcDefaultValueConverter<>::deserialize<ValueT, serialized_t>)>
    AdcDeviceAttribute(const IdentT& ident,
                       ST&& setter,
                       DSRT&& deserializer = utils::AdcDefaultValueConverter<>::deserialize<ValueT, SerializedT>)
        : AdcDeviceAttribute(ident, nullptr, std::forward<ST>(setter), nullptr, std::forward<DSRT>(deserializer))
    {
    }


    template <traits::adc_tuple_like TupleT,
              traits::adc_attr_setter_c ST,
              typename ValueT = std::decay_t<traits::adc_func_arg1_t<ST>>,
              typename DSRT = decltype(utils::AdcDefaultValueConverter<>::deserialize<ValueT, serialized_t>)>
    AdcDeviceAttribute(const IdentT& ident,
                       TupleT&&,
                       ST&& setter,
                       DSRT&& deserializer = utils::AdcDefaultValueConverter<>::deserialize<ValueT, SerializedT>)
        : AdcDeviceAttribute(ident,
                             TupleT{},
                             nullptr,
                             std::forward<ST>(setter),
                             nullptr,
                             std::forward<DSRT>(deserializer))
    {
    }


    AdcDeviceAttribute(const AdcDeviceAttribute& other)
    {
        if (&other != this) {
            other._copyFunc(this);

            _serializerFunc = other._serializerFunc;
            _deserializerFunc = other._deserializerFunc;
        }
    }

    AdcDeviceAttribute(AdcDeviceAttribute&& other)
    {
        if (&other != this) {
            other._moveFunc(this);

            _serializerFunc = std::move(other._serializerFunc);
            _deserializerFunc = std::move(other._deserializerFunc);
        }
    }


    virtual ~AdcDeviceAttribute()
    {
        // _clearFunc();
    }


    /*  PUBLIC METHODS  */



    IdentT ident() const
    {
        return _ident;
    }

    AccessType accessType() const
    {
        return _accessType;
    }


    template <traits::adc_attr_convfunc_c FromFuncT, traits::adc_attr_convfunc_c ToFuncT>
    AdcDeviceAttribute& addConvertFunc(FromFuncT&& func_from_internal, ToFuncT&& func_to_internal)
    {
        // using value_t = ret_value_t<ToFuncT>;  // it must be internal value type
        // using user_t = ret_value_t<FromFuncT>;

        using value_t = traits::attr_internal_t<FromFuncT, ToFuncT>;
        using user_t = traits::attr_user_t<FromFuncT, ToFuncT>;

        static_assert(!std::is_null_pointer_v<value_t>,
                      "Deduced attribute internal type must not be std::nullptr_t!!!");
        static_assert(!std::is_null_pointer_v<user_t>, "Deduced user-defined type must not be std::nullptr_t!!!");

        try {
            if (_accessType != AdcDeviceAttribute::WriteOnly) {
                auto& getter = _getterFunc<value_t>.at(this);  // throw out_of_range if value_t is invalid

                _getterFunc<user_t>[this] =
                    [&getter, wrapper = traits::adc_pf_wrapper(std::forward<FromFuncT>(func_from_internal)), this]() {
                        auto val = getter();
                        return std::get<0>(wrapper)(val);  // convert from internal type
                    };
            }  // ignore "from_internal" conversional function for write-only attribute



            if (_accessType != AdcDeviceAttribute::ReadOnly) {
                auto& setter = _setterFunc<value_t>.at(this);  // throw out_of_range if value_t is invalid

                _setterFunc<user_t>[this] = [&setter,
                                             wrapper = traits::adc_pf_wrapper(std::forward<ToFuncT>(func_to_internal)),
                                             this](const user_t& val) {
                    value_t value = std::get<0>(wrapper)(val);  // convert to internal type
                    setter(value);
                };
            }  // ignore "to_internal" conversional function for read-only attribute
        } catch (const std::out_of_range&) {
            throw std::system_error(AdcDeviceAttributeErrorCode::ERROR_INTERNAL_TYPE_MISMATCH);
        }

        _clearFunc = [prev_clear = _clearFunc, this]() {
            prev_clear();

            _getterFunc<user_t>.erase(this);
            _setterFunc<user_t>.erase(this);
        };


        // copy TO other
        _copyFunc = [prev_copy = _copyFunc, this](AdcDeviceAttribute* other) {
            prev_copy(other);

            _getterFunc<user_t>.emplace(other, _getterFunc<user_t>[this]);
            _setterFunc<user_t>.emplace(other, _setterFunc<user_t>[this]);

            // redefine copy-function for newly constructed instance
            // other._copyFunc was defined in the 'prev_copy(other)' call above
            other->_moveFunc = [other, copy_f = other->_copyFunc](AdcDeviceAttribute* o_next) {
                copy_f(o_next);

                _getterFunc<user_t>.emplace(o_next, _getterFunc<user_t>[other]);
                _setterFunc<user_t>.emplace(o_next, _setterFunc<user_t>[other]);
            };
        };

        // move TO other
        _moveFunc = [prev_move = _moveFunc, this](AdcDeviceAttribute* other) {
            prev_move(other);

            _getterFunc<user_t>.emplace(other, std::move(_getterFunc<user_t>[this]));
            _setterFunc<user_t>.emplace(other, std::move(_setterFunc<user_t>[this]));

            // redefine move-function for newly constructed instance
            // other._moveFunc was defined in the 'prev_move(other)' call above
            other->_moveFunc = [other, move_f = other->_moveFunc](AdcDeviceAttribute* o_next) {
                move_f(o_next);

                _getterFunc<user_t>.emplace(o_next, std::move(_getterFunc<user_t>[other]));
                _setterFunc<user_t>.emplace(o_next, std::move(_setterFunc<user_t>[other]));
            };
        };

        return *this;
    }

    template <typename UT>
    operator UT() const
    {
        if (_accessType == WriteOnly) {
            throw std::system_error(AdcDeviceAttributeErrorCode::ERROR_WRITE_ONLY);
        }

        using val_t = std::decay_t<UT>;

        try {
            return _getterFunc<val_t>.at(this)();
        } catch (const std::out_of_range&) {
            throw std::system_error(AdcDeviceAttributeErrorCode::ERROR_NO_CONV_FUNC);
        }
    }

    template <typename UT>
    AdcDeviceAttribute& operator=(UT&& val)
    {
        if (_accessType == ReadOnly) {
            throw std::system_error(AdcDeviceAttributeErrorCode::ERROR_READ_ONLY);
        }

        using val_t = std::decay_t<UT>;

        try {
            _setterFunc<val_t>.at(this)(std::forward<UT>(val));
        } catch (const std::out_of_range&) {
            throw std::system_error(AdcDeviceAttributeErrorCode::ERROR_NO_CONV_FUNC);
        }

        return *this;
    }


    AdcDeviceAttribute& operator=(const AdcDeviceAttribute& other)
    {
        if (&other != this) {
            other._copyFunc(this);

            _serializerFunc = other._serializerFunc;
            _deserializerFunc = other._deserializerFunc;
        }

        return *this;
    }


    AdcDeviceAttribute& operator=(AdcDeviceAttribute&& other)
    {
        if (&other != this) {
            other._moveFunc(this);

            _serializerFunc = std::move(other._serializerFunc);
            _deserializerFunc = std::move(other._deserializerFunc);
        }

        return *this;
    }

    serialized_t serialize()
    {
        if (_accessType == AdcDeviceAttribute::WriteOnly) {
            throw std::system_error(AdcDeviceAttributeErrorCode::ERROR_WRITE_ONLY);
        }

        return _serializerFunc();
    }

    template <typename ST>
        requires(!std::convertible_to<serialized_t, std::decay_t<ST>>)
    ST serialize()
    {
        using s_t = std::decay_t<ST>;

        if constexpr (traits::adc_output_char_range<s_t> && traits::adc_output_char_range<serialized_t>) {
            s_t res;
            std::ranges::copy(serialize(), std::back_inserter(res));
        } else {
            static_assert(false, "INVALID USER SERIALIZATION TYPE!");
        }
    }

    AdcDeviceAttribute& deserialize(const serialized_t& sval)
    {
        if (_accessType == AdcDeviceAttribute::ReadOnly) {
            throw std::system_error(AdcDeviceAttributeErrorCode::ERROR_READ_ONLY);
        }

        _deserializerFunc(sval);

        return *this;
    }

    template <typename ST>
        requires(!std::convertible_to<std::decay_t<ST>, serialized_t>)
    AdcDeviceAttribute& deserialize(const ST& sval)
    {
        using s_t = std::decay_t<ST>;

        if constexpr (traits::adc_input_char_range<s_t> && traits::adc_input_char_range<serialized_t>) {
            _deserializerFunc(serialized_t(sval.begin(), sval.end()));
        } else {
            static_assert(false, "INVALID USER SERIALIZATION TYPE!");
        }

        return *this;
    }


    /*   some usefull factory functions   */

    template <typename... CtorArgTs>
    static AdcDeviceAttribute makeArithAttr(const IdentT& ident, CtorArgTs... ctor_args)
    {
        return AdcDeviceAttribute{ident, constants::AdcDefaultTrivialConvTypes, std::forward<CtorArgTs>(ctor_args)...};
    }

protected:
    IdentT _ident;
    AccessType _accessType;


    template <typename VT, size_t I, typename TupleT>
    void setupTrivialConvertFuncImpl()
    {
        if constexpr (I < std::tuple_size_v<TupleT>) {
            using elem_t = std::tuple_element_t<I, TupleT>;

            if constexpr (!std::is_same_v<VT, elem_t>) {
                addConvertFunc([](const VT& v) { return static_cast<elem_t>(v); },
                               [](const elem_t& v) { return static_cast<VT>(v); });
            }

            setupTrivialConvertFuncImpl<VT, I + 1, TupleT>();
        }
    }

    template <typename VT, typename TupleT>
    void setupTrivialConvertFunc()
    {
        setupTrivialConvertFuncImpl<VT, 0, TupleT>();
    }
};


}  // namespace adc