// https://mariusbancila.ro/blog/2018/02/27/stduuid-a-cpp-library-for-universally-unique-identifiers/


// #pragma once

#include <string>
#include <random>
#include <iostream>

std::string get_uuid() {
    static std::random_device dev;
    static std::mt19937_64 rng(dev());

    std::uniform_int_distribution<int> dist(0, 15);
    const char *v = "0123456789abcdef";
    const bool dash[] = { 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0 };

    std::string res;
    res.reserve(40);
    for (int i = 0; i < 16; i++) {
        if (dash[i]) res += "-";
        res += v[dist(rng)];
        res += v[dist(rng)];
    }
    return res;
}

// g++ uuid_test.cpp
int main() {
        auto uuid_str = get_uuid();

        std::cout << uuid_str << std::endl;
}