#include <ranczo-io/utils/date_utils.hpp>

#include <boost/date_time/posix_time/posix_time.hpp>

namespace ranczo::date {
std::optional< std::chrono::system_clock::time_point > parse_timestamp_utc(std::string_view sv) noexcept {
    try {
        // Strip trailing 'Z' if present; Boost expects no timezone marker
        std::string s(sv);
        if(!s.empty() && (s.back() == 'Z' || s.back() == 'z'))
            s.pop_back();

        // Parse as extended ISO string
        using namespace boost::posix_time;
        ptime t = from_iso_extended_string(s); // may throw on invalid
        static const ptime epoch{boost::gregorian::date{1970, 1, 1}};
        time_duration d = t - epoch;

        // Keep sub-second precision if present (microseconds is enough for the given example)
        auto us = d.total_microseconds();
        return std::chrono::system_clock::time_point{std::chrono::microseconds{us}};
    } catch(...) {
        return std::nullopt;
    }
}

std::pmr::string to_iso_timestamp(std::chrono::system_clock::time_point tp, std::pmr::memory_resource *mr)
{
    BOOST_ASSERT(mr);
    char buf[32]={};

    std::time_t t = std::chrono::system_clock::to_time_t(tp);
    std::tm tm    = *std::gmtime(&t);

    std::strftime(buf, sizeof(buf), "%FT%TZ", &tm);

    return {buf, mr};
}

} // namespace ranczo::date