#include "date/tz.h"
#include <chrono>
#include <iostream>
#include <string>
#include <thread>
#include <mutex>

std::ostream&
print_one(std::ostream& os)
{
    return os;
}

template <class A0, class ...Args>
std::ostream&
print_one(std::ostream& os, const A0& a0, const Args& ...args)
{
    os << a0;
    return print_one(os, args...);
}

template <class ...Args>
std::ostream&
print(std::ostream& os, const Args& ...args)
{
    return print_one(os, args...);
}

std::mutex&
get_cerr_mutex()
{
    static std::mutex m;
    return m;
}

template <class ...Args>
std::ostream&
print(const Args& ...args)
{
    std::lock_guard<std::mutex> _(get_cerr_mutex());
    return print(std::cerr, args...);
}


void
daily_work(std::string msg, date::time_zone const* tz)
{
    using namespace date;
    using namespace std::chrono;
    zoned_seconds zt{tz, floor<seconds>(system_clock::now())};
    zt = floor<days>(zt.get_local_time()) + days{1};
    while (true)
    {
        std::this_thread::sleep_until(zt.get_sys_time());
        print(msg, " : ", zt.get_local_time(), '\n');
        zt = zt.get_local_time() + days{1};
    }
}

int
main()
{
    using namespace date;
    using namespace std;
    thread t1{daily_work, "Newfoundland Stanard Time", locate_zone("America/St_Johns")};
    thread t2{daily_work, "India Standard time", locate_zone("Asia/Kolkata")};
    thread t3{daily_work, "+0545", locate_zone("Asia/Kathmandu")};
    t3.join();
    t2.join();
    t1.join();
}