#include <iostream> //for cout
#include <ctime>    //for the functions time and localtime
#include "date.h"
using namespace std;

const int date::length[] {
	 0,   //dummy, so that January will have subscript 1
	31,   //January
	28,   //February.  Pretend there are no leap years.
	31,   //March
	30,   //April
	31,   //May
	30,   //June
	31,   //July
	31,   //August
	30,   //September
	31,   //October
	30,   //November
	31    //December
};

date::date(int m, int d, int y)
	: day(365 * y + d - 1)
{
	for (int month {1}; month < m; ++month) {
		day += length[month];
	}
}

date::date()   //today's date
{
	const time_t t {time(nullptr)};
	const tm *const p = localtime(&t);
	day = 365 * (p->tm_year + 1900) + p->tm_mday - 1;

	for (int month {1}; month < p->tm_mon + 1; ++month) {
		day += length[month];
	}
}

ostream& operator<<(ostream& ost, const date& d)
{
	const int year {d.day / 365};
	int dayOfYear  {d.day % 365 + 1};  //1 to 365 inclusive

	int month {1};
	for (; dayOfYear > date::length[month]; ++month) {
		dayOfYear -= date::length[month];
	}

	return ost << month << "/" << dayOfYear << "/" << year;
}

istream& operator>>(istream& ist, date& d)
{
	int month {0};
	ist >> month;
	if (!ist) {   //If the attempted input was not successful,
		return ist;
	}

	char c {'\0'};
	ist >> c;
	if (!ist) {
		return ist;
	}

	if (c != '/') {
		ist.setstate(ios_base::failbit);   //Make ist unhealthy.
		return ist;
	}

	int day;
	ist >> day;
	if (!ist) {
		return ist;
	}

	ist >> c;
	if (!ist) {
		return ist;
	}

	if (c != '/') {
		ist.setstate(ios_base::failbit);
		return ist;
	}

	int year;
	ist >> year;
	if (!ist) {
		return ist;
	}

	if (month < 1 || month > 12
		|| day < 1 || day > date::length[month]) {
		ist.setstate(ios_base::failbit);
		return ist;
	}

	//Now that we have valid data, put it into the data member.

	d.day = 365 * year + day - 1;
        for (int m {1}; m < month; ++m) {
                d.day += date::length[m];
        }

	return ist;
}