cppscripts/statustime.cpp

// Print date and time for i3 status bar.
/* i3blocks config:
 * [time]
 * command=statustime
 * interval=persist
 * markup=pango
 */

#include <fmt/chrono.h>
#include <fmt/core.h>

#include <chrono>
#include <csignal>
#include <exception>
#include <iostream>
#include <locale>
#include <thread>

void signal_handler(int signum)
{
    switch (signum)
    {
    case SIGTERM:
    case SIGINT:
    {
        std::cout << R"(<span color="red">Time script terminated.</span>)"
                  << std::endl;
        std::exit(signum); // NOLINT(concurrency-mt-unsafe)
        break;
    }
    default:
    {
        break;
    }
    }
}

int main()
{
    using fmt::format;
    using std::cout;
    using std::endl;
    using clock = std::chrono::system_clock;
    using std::chrono::minutes;
    using namespace std::chrono_literals;

    // Set explicitly, because LC_TIME is en_DK.UTF-8.
    std::locale::global(std::locale("de_DE.UTF-8"));

    std::signal(SIGINT, signal_handler);
    std::signal(SIGTERM, signal_handler);

    try
    {
        while (true)
        {
            const auto now{clock::now()};
            cout << format(R"(<b><span color="orange">{0:%A}</span></b>, )"
                           R"({0:%Y-%m-%d} )"
                           R"(<span color="lightcyan">{0:%H:%M}</span>)",
                           now)
                 << endl; // NOTE: Don't forget that we need to flush! 😊

            const auto next_minute{std::chrono::floor<minutes>(now + 1min)};
            std::this_thread::sleep_until(next_minute);
        }
    }
    catch (const std::exception &e)
    {
        cout << R"(<span color="red">Time script crashed.</span>)" << endl;
        std::cerr << e.what() << '\n';
        return 33;
    }
}