pocketpy/include/pybind11/internal/class.h

#pragma once

#include "cpp_function.h"

namespace pybind11 {

class module : public object {

public:
    using object::object;

    static module import(const char* name) {
        if(name == std::string_view{"__main__"}) {
            return module{vm->_main, true};
        } else {
            return module{vm->py_import(name, false), true};
        }
    }
};

// TODO:
// 1. inheritance
// 2. virtual function
// 3. factory function

template <typename T, typename... Others>
class class_ : public type {
public:
    using type::type;

    template <typename... Args>
    class_(const handle& scope, const char* name, Args&&... args) :
        type(vm->new_type_object(scope.ptr(), name, vm->tp_object, false, pkpy::PyTypeInfo::Vt::get<instance>()),
             true) {
        pkpy::PyVar mod = scope.ptr();
        mod->attr().set(name, m_ptr);
        vm->_cxx_typeid_map[typeid(T)] = _builtin_cast<pkpy::Type>(m_ptr);
        vm->bind_func(m_ptr, "__new__", -1, [](pkpy::VM* vm, pkpy::ArgsView args) {
            auto cls = _builtin_cast<pkpy::Type>(args[0]);
            return instance::create<T>(cls);
        });
    }

    /// bind constructor
    template <typename... Args, typename... Extra>
    class_& def(init<Args...>, const Extra&... extra) {
        if constexpr(!std::is_constructible_v<T, Args...>) {
            static_assert(std::is_constructible_v<T, Args...>, "Invalid constructor arguments");
        } else {
            bind_function(
                *this,
                "__init__",
                [](T* self, Args... args) {
                    new (self) T(args...);
                },
                pkpy::BindType::DEFAULT,
                extra...);
            return *this;
        }
    }

    /// bind member function
    template <typename Fn, typename... Extra>
    class_& def(const char* name, Fn&& f, const Extra&... extra) {
        using first = std::tuple_element_t<0, callable_args_t<remove_cvref_t<Fn>>>;
        constexpr bool is_first_base_of_v = std::is_reference_v<first> && std::is_base_of_v<T, remove_cvref_t<first>>;

        if constexpr(!is_first_base_of_v) {
            static_assert(is_first_base_of_v,
                          "If you want to bind member function, the first argument must be the base class");
        } else {
            bind_function(*this, name, std::forward<Fn>(f), pkpy::BindType::DEFAULT, extra...);
        }

        return *this;
    }

    /// bind operators
    template <typename Operator, typename... Extras>
    class_& def(Operator op, const Extras&... extras) {
        op.execute(*this, extras...);
        return *this;
    }

    // TODO: factory function

    /// bind static function
    template <typename Fn, typename... Extra>
    class_& def_static(const char* name, Fn&& f, const Extra&... extra) {
        bind_function(*this, name, std::forward<Fn>(f), pkpy::BindType::STATICMETHOD, extra...);
        return *this;
    }

    template <typename MP, typename... Extras>
    class_& def_readwrite(const char* name, MP mp, const Extras&... extras) {
        if constexpr(!std::is_member_object_pointer_v<MP>) {
            static_assert(std::is_member_object_pointer_v<MP>, "def_readwrite only supports pointer to data member");
        } else {
            bind_property(*this, name, mp, mp, extras...);
        }
        return *this;
    }

    template <typename MP, typename... Extras>
    class_& def_readonly(const char* name, MP mp, const Extras&... extras) {
        if constexpr(!std::is_member_object_pointer_v<MP>) {
            static_assert(std::is_member_object_pointer_v<MP>, "def_readonly only supports pointer to data member");
        } else {
            bind_property(*this, name, mp, nullptr, extras...);
        }
        return *this;
    }

    template <typename Getter, typename Setter, typename... Extras>
    class_& def_property(const char* name, Getter&& g, Setter&& s, const Extras&... extras) {
        bind_property(*this, name, std::forward<Getter>(g), std::forward<Setter>(s), extras...);
        return *this;
    }

    template <typename Getter, typename... Extras>
    class_& def_property_readonly(const char* name, Getter&& mp, const Extras&... extras) {
        bind_property(*this, name, std::forward<Getter>(mp), nullptr, extras...);
        return *this;
    }

    template <typename Var, typename... Extras>
    class_& def_readwrite_static(const char* name, Var& mp, const Extras&... extras) {
        static_assert(
            dependent_false<Var>,
            "define static properties requires metaclass. This is a complex feature with few use cases, so it may never be implemented.");
        return *this;
    }

    template <typename Var, typename... Extras>
    class_& def_readonly_static(const char* name, Var& mp, const Extras&... extras) {
        static_assert(
            dependent_false<Var>,
            "define static properties requires metaclass. This is a complex feature with few use cases, so it may never be implemented.");
        return *this;
    }

    template <typename Getter, typename Setter, typename... Extras>
    class_& def_property_static(const char* name, Getter&& g, Setter&& s, const Extras&... extras) {
        static_assert(
            dependent_false<Getter>,
            "define static properties requires metaclass. This is a complex feature with few use cases, so it may never be implemented.");
        return *this;
    }
};

template <typename T, typename... Others>
class enum_ : public class_<T, Others...> {
    std::map<const char*, pkpy::PyVar> m_values;

public:
    using class_<T, Others...>::class_;

    template <typename... Args>
    enum_(const handle& scope, const char* name, Args&&... args) :
        class_<T, Others...>(scope, name, std::forward<Args>(args)...) {}

    enum_& value(const char* name, T value) {
        handle var = type_caster<T>::cast(value, return_value_policy::copy);
        this->m_ptr->attr().set(name, var.ptr());
        m_values[name] = var.ptr();
        return *this;
    }

    enum_& export_values() {
        pkpy::PyVar mod = this->m_ptr->attr("__module__");
        for(auto& [name, value]: m_values) {
            mod->attr().set(name, value);
        }
        return *this;
    }
};
}  // namespace pybind11