toolkit/include/toolkit.h

#ifndef TOOLKIT_H
#define TOOLKIT_H

#include <charconv>
#include <cstring>
#include <expected>
#include <type_traits>
#include <string>
#include <cstdlib>
#include <ios>
#include <vector>
#include <ranges>
#include <cmath>
#include <chrono>

namespace ranges = std::ranges;
namespace views = std::ranges::views;

// use for to_chars
constexpr size_t buffer_size = 32;

template <typename T>
concept _num_type = requires {
    std::is_same_v<T, int> ||
        std::is_same_v<T, float> ||
        std::is_same_v<T, long> ||
        std::is_same_v<T, double>;
};

namespace toolkit
{
    template <typename T>
    std::expected<std::string, std::string> to_string(T value)
    {
        if constexpr (std::is_same_v<T, int> || std::is_same_v<T, float> || std::is_same_v<T, double>)
        {
            char buffer[buffer_size];
            auto res = std::to_chars(buffer, buffer + buffer_size, value);
            if (res.ec != std::errc())
            {
                return std::unexpected(std::make_error_code(res.ec).message());
            }
            return std::string(buffer, res.ptr - buffer);
        }
        else if constexpr (std::is_same_v<typename std::remove_const<T>::type,
                                          char *>)
        {
            return std::to_string(value);
        }
    }

    template <typename T = double> // requires std::is_same_v<T, std::string>
    std::expected<T, std::string> stoi(const std::string &str)
    {
        T value;
        auto res = std::from_chars(str.c_str(), str.c_str() + str.size(), value);
        if (res.ec != std::errc())
        {
            return std::unexpected(std::make_error_code(res.ec).message());
        }
        return value;
    }

    template <typename T>
        requires std::is_same_v<std::string, T> || std::is_same_v<const char *, T>
    std::string replace_string(const std::string &str, T d, T e)
    {
        std::string result = str;
        if (d == e)
        {
            return result;
        }
        size_t len = 0;
        while (true)
        {
            auto pos = result.find(d);
            if (pos == std::string::npos)
            {
                return result;
            }
            if constexpr (std::is_same_v<T, const char *>)
            {
                len = std::strlen(d);
            }
            else
            {
                len = d.length();
            }
            result = result.replace(pos, len, e);
        }
    }

    template <typename T = std::string>
        requires std::is_same_v<T, std::string> ||
                 std::is_same_v<T, std::string_view>
    std::vector<T> split(T str, T d)
    {
        auto v = views::split(str, d) | views::transform([](auto word)
                                                         { return T(word.begin(), word.end()); });
        return std::vector<T>(v.begin(), v.end());
    }
    
    template<typename T>
        requires std::is_same_v<T, double> || std::is_same_v<T, float>
    double round(T value, int c){
        auto temp = 1;
        for(int i=0;i<c;i++){
            temp=temp*10;
        }
        return std::round(value*temp)/temp;
    }

    inline std::string get_time_now(){
        auto time_now = std::chrono::system_clock::now();
        auto now_c = std::chrono::system_clock::to_time_t(time_now);
        char buffer[32];
#if defined(_WIN32) || defined(_WIN64)
        auto _ = ctime_s(buffer, 32, &now_c);
#elif defined(__linux__)
        auto _ = ctime_r(&now_c, buffer);
#endif
        auto result = std::string(buffer);
        result = replace_string(result, "\n", "");
        return std::move(result);
    }

}

#endif