/* With no command line arguments, it outputs a drawing of the current phase of
the moon.  Or you can specify three arguments in decimal to see the phase of the
moon at midnight on that date:
	first argument, day: 1 to 31 inclusive
	second argument, month: 1 to 12 inclusive
	third argument, year: don't forget the leading 19.

Translated from the BASIC version in Celestial Basic: Astronomy on your Computer
by Eric Burgess; Sybex, 1982; pp. 65-71.


This file is moonmain.c.  It is one of the three .c files that must be compiled
to create the executable program moon.  Give the -lm argument (for "math
library") to cc at the end of the command line.
*/

#include <stdio.h>
#include <stdlib.h>	/* declaration for exit function */
#include <sys/types.h>
#include <time.h>
#include "moon.h"

main (int argc, char **argv)
{
	int year;
	int month;
	int day;
	int hour;
	int minute;
	int second;
	double radians;

	if (argc == 1) {
		time_t clock = time((time_t *)NULL);
		struct tm *p = localtime(&clock);

		year = p->tm_year + 1900;
		month = p->tm_mon + 1;
		day = p->tm_mday;
		hour = p->tm_hour;
		minute = p->tm_min;
		second = p->tm_sec;
	} else if (argc == 4) {
		day = atoi(argv[1]);
		month = atoi(argv[2]);
		year = atoi(argv[3]);

		hour = minute = second = 0;	/* midnight */
	} else {
		fprintf (stderr, "%s: arguments (if any): day month year\n",
			argv[0]);
		exit (1);
	}



#ifdef DEBUG
	printf ("clock, year, month, day, hour, min, sec: "
		"%d %d %d %d %d %d %d\n",
		clock, year, month, day, hour, minute, second);
#endif

	radians = phase(year, month, day, hour, minute, second);

#ifdef DEBUG
	printf ("radians == %f\n", radians);
#endif

	draw (radians);
	exit (0);
}