static char rcsid[] = "@(#)$Id: date.c,v 1.2 1995/09/29 17:42:02 wfp5p Exp $";

/*******************************************************************************
 *  The Elm Mail System  -  $Revision: 1.2 $   $State: Exp $
 *
 *                      Copyright (c) 1988-1995 USENET Community Trust
 * 			Copyright (c) 1986,1987 Dave Taylor
 *******************************************************************************
 * Bug reports, patches, comments, suggestions should be sent to:
 *
 *      Bill Pemberton, Elm Coordinator
 *      flash@virginia.edu
 *
 *******************************************************************************
 * $Log: date.c,v $
 * Revision 1.2  1995/09/29  17:42:02  wfp5p
 * Alpha 8 (Chip's big changes)
 *
 * Revision 1.1.1.1  1995/04/19  20:38:35  wfp5p
 * Initial import of elm 2.4 PL0 as base for elm 2.5.
 *
 ******************************************************************************/

/** return the current date and time in a readable format! **/
/** also returns an ARPA RFC-822 format date...            **/


#include "elm_defs.h"
#include "elm_globals.h"

#ifdef I_TIME
#  include <time.h>
#endif
#ifdef I_SYSTIME
#  include <sys/time.h>
#endif
#ifdef BSD
#  include <sys/timeb.h>
#endif

#ifndef	_POSIX_SOURCE
extern struct tm *localtime();
extern struct tm *gmtime();
extern time_t	  time();
#endif

#define MONTHS_IN_YEAR	11	/* 0-11 equals 12 months! */
#define FEB		 1	/* 0 = January 		  */
#define DAYS_IN_LEAP_FEB 29	/* leap year only 	  */

#define leapyear(year)	((year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0)))

int  days_in_month[] = { 31,    28,    31,    30,    31,     30, 
		  31,     31,    30,   31,    30,     31,  -1};

days_ahead(days, buffer)
int days;
char *buffer;
{
	/** return in buffer the date (Day, Mon Day, Year) of the date
	    'days' days after today.  
	**/

	struct tm *the_time;		/* Time structure, see CTIME(3C) */
	time_t	   junk;		/* time in seconds....		 */

	junk = time((time_t *) 0);	/* this must be here for it to work! */
	the_time = localtime(&junk);

	/* increment the day of the week */

	the_time->tm_wday = (the_time->tm_wday + days) % 7;

	/* the day of the month... */
	the_time->tm_mday += days;
	
        while (the_time->tm_mday > days_in_month[the_time->tm_mon]) {
          if (the_time->tm_mon == FEB && leapyear(the_time->tm_year+1900)) {
            if (the_time->tm_mday > DAYS_IN_LEAP_FEB) {
              the_time->tm_mday -= DAYS_IN_LEAP_FEB;
              the_time->tm_mon += 1;
            }
            else
              break;            /* Is Feb 29, so leave */
          }
          else {
            the_time->tm_mday -= days_in_month[the_time->tm_mon];
            the_time->tm_mon += 1;
          }

          /* check the month of the year */
          if (the_time->tm_mon > MONTHS_IN_YEAR) {
            the_time->tm_mon -= (MONTHS_IN_YEAR + 1);
            the_time->tm_year += 1;
          }
        }

        /* now, finally, build the actual date string */
        the_time->tm_mday %= 32,
	strftime(buffer, SLEN, "%a, %d %B %y", the_time);
}

int
month_number(name)
char *name;
{
	int retval;
	if (cvt_monthname_to_monthnum(name, &retval) < 0) {
		/* conversion failed ... pick January */
		retval = 0;
	} else {
		/* conversion routine uses Jan=1, we want Jan=0 */
		--retval;
	}
	return retval;
}

char *
elm_date_str(buf, entry, show_century)
char *buf;
struct header_rec *entry;
int show_century;
{
	time_t secs = (entry->time_sent + entry->tz_offset);
	char *fmt = (show_century ? "%b %d, %Y %r" : "%b %d, %y %r");
	strftime(buf, SLEN, fmt, gmtime(&secs));
	return buf;
}

make_menu_date(entry)
struct header_rec *entry;
{
	time_t secs = (entry->time_sent + entry->tz_offset);
	strftime(entry->time_menu, SLEN, "%b %d", gmtime(&secs));
}