AD_func.hpp

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/*
 *  AD_func.hpp
 *  Created by AD on 25/11/25
 *  Copyright (c) 2025-2026 AD All rights reserved.
**/

#ifndef _AD_FUNC_HPP_
#define _AD_FUNC_HPP_

// #include <iostream>
#include <functional>
#include <unordered_map>
#include <string>
#include <any>
#include <typeindex>
#include <type_traits>
#include <vector>
#include <mutex>
#include "AD_output.hpp"

namespace ad = AD;

namespace AD {

template<typename T> struct func_traits;

template<typename R, typename... Args>
struct func_traits<R(Args...)> {
    using return_type = R;
    using func_type = std::function<R(Args...)>;
    static constexpr const char* name = "function";
};

class DynamicSystem {
private:
    static std::unordered_map<std::string, std::any>& registry() {
        static std::unordered_map<std::string, std::any> instance;
        return instance;
    }

    static std::unordered_map<std::string, std::string>& debug_names() {
        static std::unordered_map<std::string, std::string> instance;
        return instance;
    }

public:
    template<typename F>
    static bool define(const std::string& name, F lambda) {
        try {
            auto func_wrapper = std::function(lambda); 
            registry()[name] = std::any(func_wrapper);
            debug_names()[name] = typeid(func_wrapper).name();
            return true;
        } catch (const std::exception& e) {
            ad::cerr << "[Error] Failed to register function '" << name << "': " << e.what() << ad::endl;
            return false;
        }
    }

    template<typename Sig, typename... CallArgs>
    static typename func_traits<Sig>::return_type invoke(const std::string& name, CallArgs&&... args) {
        using R = typename func_traits<Sig>::return_type;
        using FuncType = typename func_traits<Sig>::func_type;

        auto& reg = registry();
        auto it = reg.find(name);
        
        if (it == reg.end()) {
            ad::cerr << "[Error] Function '" << name << "' not found!" << ad::endl;
            if constexpr (!std::is_void_v<R>) return R{};
            else return;
        }

        try {
            auto f = std::any_cast<FuncType>(it->second);
            return f(std::forward<CallArgs>(args)...);
        } catch (const std::bad_any_cast& e) {
            ad::cerr << "[Fatal] Type mismatch for '" << name << "'\n";
            ad::cerr << "  Expected: " << typeid(FuncType).name() << "\n";
            ad::cerr << "  Stored:   " << debug_names()[name] << "\n";
            if constexpr (!std::is_void_v<R>) return R{};
        }
    }
    
    static bool exists(const std::string& name) {
        return registry().find(name) != registry().end();
    }
    
    static std::vector<std::string> list_functions() {
        std::vector<std::string> names;
        names.reserve(registry().size());
        for (const auto& [name, _] : registry()) {
            names.push_back(name);
        }
        return names;
    }
    
    static void clear() {
        registry().clear();
        debug_names().clear();
    }
};

/*

struct AutoRegHelper {
    std::string name;
    AutoRegHelper(const char* n) : name(n) {}

    template <typename F>
    int operator=(F&& f) {
        AD::DynamicSystem::define(name, std::forward<F>(f));
        return 0;
    }
};

*/

struct AutoRegHelper {
    std::string name;
    AutoRegHelper(const char* n) : name(n) {}
    template <typename F>
    int operator=(F&& f) {
        AD::DynamicSystem::define(name, std::forward<F>(f));
        return 0;
    }
};

} // namespace AD

#define adfunc(name) inline static int _reg_##name = AD::AutoRegHelper(#name) = [] 

#define adfunccall(name, Sig, ...) \
    AD::DynamicSystem::invoke<Sig>(#name, ##__VA_ARGS__)

#define adfuncsafecall(name, Sig, default_val, ...) \
    ([&]() -> typename AD::func_traits<Sig>::return_type { \
        if (AD::DynamicSystem::exists(#name)) { \
            try { \
                return AD::DynamicSystem::invoke<Sig>(#name, ##__VA_ARGS__); \
            } catch (...) { \
                ad::cerr << "[Warn] Call failed for " << #name << ", using default.\n"; \
                return default_val; \
            } \
        } \
        ad::cerr << "[Warn] Function " << #name << " not found, using default.\n"; \
        return default_val; \
    }())

// #define ad_func adfunc
#define adfunc_call adfunccall

#define newadfunc(name) inline static int _reg_##name = AD::AutoRegHelper(#name) = [&]

#define new_adfunc newadfunc
#define adfunc_safe_call adfuncsafecall
#endif