/* sdate.c 
 *
 * Gets the current date and time from the system, and emits the short form
 * mm/dd/yy as a string.
 *
 * -x: emit extended terse form mm/dd/yy hh:mm:ss
 * -t: emit time in the form hh:mm
 *
 * -w: emit week day as 0-6 for sun-sat
 *	simultaneously -C:	Fri e.g.
 *		       -V:      FRI
 *		       -v:      fri
 *
 * -d: emit zero padded day of the month as 01-31
 * -h: emit zero padded hour of the day 00-23
 * -M: emit zero padded minute of the hour 00-59
 *
 * With option -l, emits current date suitable for a letter
 */

#include <stdio.hgt;
#include  <ascii.hgt; 
#include  <stdfun.hgt; 
#include <string.hgt;
#include <sys/types.hgt;
#include <time.hgt;

#define OPTSTRING "lxCMymnstdhvVwST:"

#define EMIT_DATE	1
#define EMIT_TIME	2
#define EMIT_DATE_TIME	3
#define EMIT_WKDAY	4

#define FALSE		0
#define TRUE		1

#define SHORTDATESZ	3
#define DATESZ		10

char *Month[]  =  {

	"January\0",
	"February\0",
	"March\0",
	"April\0",
	"May\0",
	"June\0",
	"July\0",
	"August\0",
	"September\0",
	"October\0",
	"November\0",
	"December\0"
};
char *day[]  =  {

	"sun\0",
	"mon\0",
	"tue\0",
	"wed\0",
	"thu\0",
	"fri\0",
	"sat\0"
};

struct tm tm0, *ptm0;
long sysclocktime;

int verbose, startime, shorterdate, emityear, emitmonth;
int emitmonthday, wkday, emithour, emitminute;
int letterdate;


static char _sccsid[] = { " sdate.c 1.5 10/4/97 " };

int main( argc, argv )
int argc;
char *argv[];
{
	extern int toupper();
	extern int getopt();
	extern long time();

	char *sputdate(), *addmins(), *stoupper();

	extern int optind;
	extern char *optarg;	/* Captures arguments to options */

	int c_date[ SHORTDATESZ ];
	char c_datestr[ DATESZ ];
	int adv_mins;
	int emit;
	char end;

	int c_opt;

	/* Defaults */
	emit = EMIT_DATE;

	startime = FALSE;
	letterdate = FALSE;
	shorterdate = FALSE;
	emityear = FALSE;
	emitmonth = FALSE;
	emitmonthday = FALSE;
	emithour = FALSE;
	emitminute = FALSE;
	verbose = FALSE;
	end = NUL;

	while( ( c_opt = getopt( argc, argv, OPTSTRING ) ) != EOF )    {
		switch( c_opt )    {
			case 'l':
				/* -l */
				letterdate = TRUE;
				break;
			case 'm':
				/* -m */
				emitmonth = TRUE;
				break;
			case 'd':
				/* -d */
				emitmonthday = TRUE;
				break;
			case 'y':
				/* -y */
				emityear = TRUE;
				break;
			case 'n':
				/* -n */
				end = LF;
				break;
			case 'S':
				/* -S: Use "star time" */
				startime = TRUE;
				break;
			case 's':
				/* -s: Use "shorter date mm[/]dd" */
				shorterdate = TRUE;
				break;
			case 'M':
				/* -M */
				emit = EMIT_TIME;
				emitminute = TRUE;
				break;
			case 'x':
				/* -x */
				emit = EMIT_DATE_TIME;
				break;
			case 'h':
				/* -h */
				emit = EMIT_TIME;
				emithour = TRUE;
				break;
			case 't':
				/* -t */
				emit = EMIT_TIME;
				adv_mins = 0;
				break;
			case 'w':
				/* -w */
				emit = EMIT_WKDAY;
				break;
			case 'v':
				/* -v */
				verbose = 1;
				break;
			case 'V':
				/* -V */
				verbose = 2;
				break;
			case 'C':
				/* -C */
				verbose = 3;
				break;
			case 'T':
				/* -T arg */
				emit = EMIT_TIME;
				sscanf( optarg, "%d", &adv_mins );
				break;
			default:
				fprintf( stderr, "%s: Bad Option -%c\n", argv[0], c_opt );
				fprintf( stderr, "Usage: %s -[%s]\n", argv[0], OPTSTRING );
				exit( 1 );
		}
	}

	ptm0 = &tm0;

	/* One should always give the explicit null argument, since the old
	 * syntax time( &clock ) is still operative
	 */
	sysclocktime = time( (long *) 0 );

	ptm0 = localtime( &sysclocktime );

	if( emit == EMIT_DATE )    {
		/* Globals */
		c_date[0] = ptm0-gt;tm_mon;
		c_date[1] = ptm0-gt;tm_mday;
		c_date[2] = ptm0-gt;tm_year;

		/* sputdate() corrects System c_date[] so worldly date
		 * is printed into character array c_datestr.
		 */
		if( emitmonthday )    {
			printf( "%02d", c_date[ 1 ] );
			if( end == LF )
				putchar( LF );
			exit( 0 );
		}
		else if( letterdate )    {
			printf( "%s %d, 19%d\n", Month[ c_date[ 0 ] ], c_date[ 1 ], c_date[ 2 ] );
			exit( 0 );
		}
		else    {
			sputdate( c_date, c_datestr, end );
		}

	}
	else if( emit == EMIT_TIME )    {
		/* Globals */
		c_date[0] = ptm0-gt;tm_hour;
		c_date[1] = ptm0-gt;tm_min;
		if( emithour )    {
			printf( "%02d", c_date[0] );
			if( end == LF )
				putchar( LF );
			exit( 0 );
		}
		else if( emitminute )    {
			printf( "%02d", c_date[1] );
			if( end == LF )
				putchar( LF );
			exit( 0 );
		}
		else    {
			addmins( c_date, c_datestr, adv_mins, end ); 
		}
	}
	else if( emit == EMIT_DATE_TIME )    {
		printf( "%02d/%02d/%02d %02d:%02d:%02d",
			ptm0-gt;tm_mon + 1,
			ptm0-gt;tm_mday,
			ptm0-gt;tm_year,
			ptm0-gt;tm_hour,
			ptm0-gt;tm_min,
			ptm0-gt;tm_sec );
		if( end == LF )
			putchar( LF );
		exit( 0 );
	}
	else    {
		/* emit WEEK_DAY */
		wkday = ptm0-gt;tm_wday;
		if( verbose == 0 )    {
			sprintf( c_datestr, "%d%c", wkday, end );
		}
		else if( verbose == 1 )    {
			sprintf( c_datestr, "%s%c", day[ wkday ], end );
		}
		else if( verbose == 2 )    {
			sprintf( c_datestr, "%s%c", stoupper( day[ wkday ], DATESZ ), end );
		}
		else if( verbose == 3 )    {
			sprintf( c_datestr, "%s%c", day[ wkday ], end );
			c_datestr[0] = (char)toupper( c_datestr[0] );
		}
	}

	printf( "%s", c_datestr );

	exit( 0 );
	return( 0 );

} /* end main() */

/* Put a zero padded date into string.
 * Assumed that string is at least of size DATELEN.
 * Since this is meant for printing to the world
 * we adjust the month number to the worldly number if the address of
 * the integer array is the address of the global c_date[] which contains
 * the date in system form.
 * 'end' is the prescribed char preceding the terminal NUL.
 * Called by gtsysdate() to write global c_datestr[].
 */
char *sputdate( d, l, end ) /* put 0-padded short date to string */
int *d;
char *l;
char end;
{

	if( emityear )    {
		sprintf( l, "%02d%c", d[2], end );
		return( l );
	}
	if( emitmonth )    {
		sprintf( l, "%02d%c", d[0] + 1, end );
		return( l );
	}

	if( startime )    {
		if( shorterdate )    {
			sprintf( l, "%02d%02d%c", d[0] + 1, d[1], end );
		}
		else    {
			sprintf( l, "%02d%02d%02d%c", d[0] + 1, d[1], d[2], end );
		}
	}
	else    {
		if( shorterdate )    {
			sprintf( l, "%02d/%02d%c", d[0] + 1, d[1], end );
		}
		else    {
			sprintf( l, "%02d/%02d/%02d%c", d[0] + 1, d[1], d[2], end );
		}
	}

	return( l );
}

char *addmins( t, tstr, advm, end )
int *t;
char *tstr;
int advm;
char end;
{
	int hrs, mins;

	hrs = t[ 0 ];
	mins = t[ 1 ];

	while( (mins + advm) gt;= 60 )    {
		++hrs;
		advm -= 60;
	}
	mins +=advm;
	if( startime )    {
		sprintf( tstr, "%02d%02d%c", hrs, mins, end );
	}
	else    {
		sprintf( tstr, "%02d:%02d%c", hrs, mins, end );
	}
	return( tstr );
}

char *stoupper( str, sz ) /* String to upper */
char *str;
int sz;
{
	extern int toupper();
	--sz;
	while( sz-- )
		str[ sz ] = (char)toupper( str[ sz ] );
	return( str );
}