//	Since I need my own time and duration types,
//	that have the same binary representation on all
//	operating systems and environmens

#include "stdafx.h"



/*I have spent far, far too much time trying to get overly clever layers that supposedly provide OS independence to work.
*/



#ifdef  _MSC_VER
//	compiling under Microsoft Visual Studio.
#include <time.h>
#endif


namespace ro {
	//	need to define my own time types:
	//	typedef time_t time_t;  //	is signed time in seconds past the epoch modulo 2 ^ 64
	//	because in some environments, time_t is  seconds past the epoch modulo 2 ^ 32
	//	and if time_t is not 64 bits, ro:time_t is a typedef of bint_fast64_t

	ro::time_t time() { return ::time(nullptr); }
	//	equivalent to regular old time(nullptr) except in environments where time_t
	//	except in environments where time_t is seconds past the epoch modulo 2 ^ 32

	ro::sec_t system_time_now() {
		ro::sec_t uu;
		return uu + (ro::sec)(::time(nullptr));

	}

	// duration past startup time modulo 2^32 Rolls over every forty eight days, making durations longer than twenty four days of unclear sign
	msec msec_since_epoch(void){
		return std::chrono::duration_cast<ro::msec>  (std::chrono::steady_clock::now().time_since_epoch());
	}

	// date and time as utc time in human readable form
	std::string iso_utc_time(ro::time_t t) {
		std::array<char, 20> retval{ "0000-00-00t00:00:00" };
		std::tm tm_t;
		if (0 == _gmtime64_s(&tm_t, &t)) {
			strftime(retval.data(), 20, "%Y-%m-%dt%H:%M:%S", &tm_t);
		}
		return retval.data();
	}//		which is a string expressing the utc time in human readable form

	// local date and time in human readable form
	std::string iso_local_time(ro::time_t t) {
		std::array<char, 26> retval{ "0000-00-00t00:00:00-00:00" };
		std::tm tm_t;
		if (0 == _localtime64_s(&tm_t, &t)) {
			strftime(retval.data(), 20, "%Y-%m-%dt%H:%M:%S", &tm_t);
			long timezone;
			if (0 == _get_timezone(&timezone)) {
				if (timezone <= 0) {
					retval.data()[19] = '+';
					timezone = -timezone;
				}
				sprintf_s(retval.data() + 20, 6, "%2.2d:%2.2d", (timezone / 3600) % 24, ((timezone+30) / 60) % 60);
			}
		}
		return retval.data();
	}

	//	string expressing the current utc time
	std::string iso_utc_time(ro::sec_t t) {
		return ro::iso_utc_time((t.time_since_epoch()).count());
	}
	//	string expressing the current local time
	std::string iso_local_time(ro::sec_t t) {
		return ro::iso_local_time((t.time_since_epoch()).count());
	}

	//	String expressing steady system time interval
	//	Typical usage steady_clock(msec_time_now() - start_time);
	//	Always outputs eleven characters plus a null terminator.
	std::string duration_as_string(msec t) {
		std::array<char, 12> retval{ "       .000" };
		uint_fast32_t t_as_int{ t.count() };
		uint_fast32_t milliseconds{ t_as_int % 1000 };
		uint_fast32_t seconds{ t_as_int / 1000 };
		snprintf(&retval[0], retval.size(), "%7u.%03u", seconds, milliseconds);
		return retval.data();
	}
}