/**	@file gregorian.cpp
	@author Garth Santor
	@date 2013-09-19

	Gregorian calendar class implementation.
	*/

#include <khronos/gregorian_calendar.hpp>
#include <cassert>
#include <sstream>
#include <ctime>
#include <iomanip>
#include <algorithm>

namespace khronos {


		/**	Gregorian default constructor.  Initialize to the current local time. */
		Gregorian::Gregorian() {
			time_t nowTime = time(NULL);
			struct tm tmNow;
			localtime_s(&tmNow, &nowTime);
			year_ = year_t(tmNow.tm_year) + 1900;
			month_ = month_t(tmNow.tm_mon) + 1;
			day_ = day_t(tmNow.tm_mday);
		}



		/** Print the Gregorian Date as a string. */
		std::string Gregorian::to_string() const {
			std::ostringstream oss;

			// day of week
			oss << civil::day_name(khronos::civil::day_of_week(to_jd())) << ", ";

			oss << gregorian_month_name(month_) << ' ' << (unsigned)day_ << ' ';
			if (year_ <= 0)
				oss << (-year_ + 1) << " BCE";
			else
				oss << year_ << " CE";

			return oss.str();
		}



		/** Gregorian + (integer year) operator. */
		Gregorian operator + (Gregorian const& dt, detail::packaged_year_integer const& year) {
			year_t y = dt.year() + year.nYears_;
			month_t m = dt.month();
			day_t d = dt.day();

			if (m == February && d == 29 && !is_gregorian_leapyear(y))
				d = 28;

			return Gregorian(y, m, d);
		}



		/** Gregorian + (integer month) operator. */
		Gregorian operator + (Gregorian const& dt, detail::packaged_month_integer const& month) {
			year_t yearsToAdd = month.nMonths_ / 12;
			month_t monthsToAdd = month.nMonths_ % 12;
			year_t y = dt.year() + yearsToAdd;
			month_t m = dt.month() + monthsToAdd;

			int adjustment = (m - 1) / 12 + (m - 12) / 12;
			y += adjustment;
			m -= month_t(adjustment * 12);

			day_t d = std::min(dt.day(), gregorian_days_in_month(m, is_gregorian_leapyear(y)));

			return Gregorian(y, m, d);
		}
}