/*
 * datetime_functions.c --
 *
 * This file defines new functions for the time and date data types.
 *
 * Copyright (c) 1996, Massimo Dal Zotto <dz@cs.unitn.it>
 */

#include <stdio.h>				/* for sprintf() */
#include <string.h>
#include <limits.h>
#ifdef HAVE_FLOAT_H
#include <float.h>
#endif

#include "postgres.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/nabstime.h"
#include "utils/datetime.h"
#include "access/xact.h"

#include "datetime_functions.h"

/* Constant to replace calls to date2j(2000,1,1) */
#define JDATE_2000	2451545

/*
 * A modified version of time_in which allows the value 24:00:00 for
 * time and converts it to TimeADT data type forcing seconds to 0.
 * This can be Useful if you need to handle TimeADT values limited
 * to hh:mm like in timetables.
 */

TimeADT    *
hhmm_in(char *str)
{
	TimeADT    *time;

	double		fsec;
	struct tm	tt,
			   *tm = &tt;

	int			nf;
	char		lowstr[MAXDATELEN + 1];
	char	   *field[MAXDATEFIELDS];
	int			dtype;
	int			ftype[MAXDATEFIELDS];

	if (!PointerIsValid(str))
		elog(ERROR, "Bad (null) time external representation", NULL);

	if ((ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf) != 0)
		|| (DecodeTimeOnly(field, ftype, nf, &dtype, tm, &fsec) != 0))
		elog(ERROR, "Bad time external representation '%s'", str);

	if (tm->tm_hour < 0 || tm->tm_hour > 24 ||
		(tm->tm_hour == 24 && (tm->tm_min != 0 || tm->tm_sec != 0 || fsec != 0)))
	{
		elog(ERROR,
			 "time_in: hour must be limited to values 0 through 24:00 "
			 "in \"%s\"",
			 str);
	}
	if ((tm->tm_min < 0) || (tm->tm_min > 59))
		elog(ERROR, "Minute must be limited to values 0 through 59 in '%s'", str);
	if ((tm->tm_sec < 0) || ((tm->tm_sec + fsec) >= 60))
		elog(ERROR, "Second must be limited to values 0 through < 60 in '%s'",
			 str);

	time = palloc(sizeof(TimeADT));

	*time = ((((tm->tm_hour * 60) + tm->tm_min) * 60));

	return (time);
}

/*
 * A modified version of time_out which converts from TimeADT data type
 * omitting the seconds field when it is 0.
 * Useful if you need to handle TimeADT values limited to hh:mm.
 */

char *
hhmm_out(TimeADT *time)
{
	char	   *result;
	struct tm	tt,
			   *tm = &tt;
	char		buf[MAXDATELEN + 1];

	if (!PointerIsValid(time))
		return NULL;

	tm->tm_hour = (*time / (60 * 60));
	tm->tm_min = (((int) (*time / 60)) % 60);
	tm->tm_sec = (((int) *time) % 60);

	if (tm->tm_sec == 0)
	{
		sprintf(buf, "%02d:%02d", tm->tm_hour, tm->tm_min);
	}
	else
	{
		sprintf(buf, "%02d:%02d:%02d", tm->tm_hour, tm->tm_min, tm->tm_sec);
	}

	result = palloc(strlen(buf) + 1);

	strcpy(result, buf);

	return (result);
}

TimeADT    *
hhmm(TimeADT *time)
{
	TimeADT    *result = palloc(sizeof(TimeADT));

	*result = (((int) *time) / 60 * 60);

	return (result);
}

TimeADT    *
time_difference(TimeADT *time1, TimeADT *time2)
{
	TimeADT    *time = palloc(sizeof(TimeADT));

	*time = (*time1 - *time2);
	return (time);
}

int4
time_hours(TimeADT *time)
{
	return (((int) *time) / 3600);
}

int4
time_minutes(TimeADT *time)
{
	return ((((int) *time) / 60) % 60);
}

int4
time_seconds(TimeADT *time)
{
	return (((int) *time) % 60);
}

int4
as_minutes(TimeADT *time)
{
	return (((int) *time) / 60);
}

int4
as_seconds(TimeADT *time)
{
	return ((int) *time);
}

int4
date_day(DateADT val)
{
	int			year,
				month,
				day;

	j2date(val + JDATE_2000, &year, &month, &day);

	return (day);
}

int4
date_month(DateADT val)
{
	int			year,
				month,
				day;

	j2date(val + JDATE_2000, &year, &month, &day);

	return (month);
}

int4
date_year(DateADT val)
{
	int			year,
				month,
				day;

	j2date(val + JDATE_2000, &year, &month, &day);

	return (year);
}

TimeADT    *
currenttime()
{
	TimeADT    *result = palloc(sizeof(TimeADT));
	struct tm  *tm;
	time_t		current_time;

	current_time = time(NULL);
	tm = localtime(&current_time);
	*result = ((((tm->tm_hour * 60) + tm->tm_min) * 60) + tm->tm_sec);

	return (result);
}

DateADT
currentdate()
{
	DateADT		date;
	struct tm	tt,
			   *tm = &tt;

	GetCurrentTime(tm);
	date = (date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - JDATE_2000);
	return (date);
}

/* end of file */
