/*
 * 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 */
