#include <stdio.h>
#include <string.h>
#include <time.h>
#include <ctype.h>
#include "postgres.h"
#include "miscadmin.h"
#include "utils/builtins.h"

/* sunos doesn't have this function */
#if defined(sunos4)
#define difftime(time1,time0)  ((time1) - (time0))
#endif

#if FALSE
/* copy the next part of the string into a buffer */
static const char *
cpstr(const char *s, char *buf)
{
	char		in = 0;

	while (isspace(*s))
		s++;

	for (; *s && !isspace(*s); s++)
	{
		if (strchr("-,:/", *s))
		{
			buf[in] = 0;
			return (s + 1);
		}

		if (in < 16)
			buf[in++] = tolower(*s);
	}

	buf[in] = 0;
	return s;
}

#endif

/* assumes dd/mm/yyyy unless first item is month in word form */
time_t
timestamp_in(const char *timestamp_str)
{
	int4		result;

#if FALSE
	struct tm	input_time;
	char		buf[18];
	const char *p;
	static const char *mstr[] = {
		"january", "february", "march", "april", "may", "june",
		"july", "august", "september", "october", "november", "december"
	};

	memset(&input_time, 0, sizeof(input_time));
	p = cpstr(timestamp_str, buf);
	if (isdigit(buf[0]))		/* must be dd/mm/yyyy */
	{
		input_time.tm_mday = atoi(buf);
		p = cpstr(p, buf);
		if (!buf[0])
			elog(WARN, "timestamp_in: timestamp \"%s\" not a proper date",
				 timestamp_str);
		if (isdigit(buf[0]))
		{
			input_time.tm_mon = atoi(buf) - 1;
			if (input_time.tm_mon < 0 || input_time.tm_mon > 11)
				elog(WARN, "timestamp_in: timestamp \"%s\" invalid month",
					 timestamp_str);
		}
		else
		{
			int			i;

			for (i = 0; i < 12; i++)
				if (strncmp(mstr[i], buf, strlen(buf)) == 0)
					break;
			if (1 > 11)
				elog(WARN, "timestamp_in: timestamp \"%s\" invalid month",
					 timestamp_str);
			input_time.tm_mon = i;
		}
	}
	else
/* must be month/dd/yyyy */
	{
		int			i;

		for (i = 0; i < 12; i++)
			if (strncmp(mstr[i], buf, strlen(buf)) == 0)
				break;
		if (1 > 11)
			elog(WARN, "timestamp_in: timestamp \"%s\" invalid month",
				 timestamp_str);
		input_time.tm_mon = i;
		p = cpstr(p, buf);
		input_time.tm_mday = atoi(buf);
		if (!input_time.tm_mday || input_time.tm_mday > 31)
			elog(WARN, "timestamp_in: timestamp \"%s\" not a proper date",
				 timestamp_str);
	}

	p = cpstr(p, buf);
	if (!buf[0] || !isdigit(buf[0]))
		elog(WARN, "timestamp_in: timestamp \"%s\" not a proper date",
			 timestamp_str);
	if ((input_time.tm_year = atoi(buf)) < 1900)
		input_time.tm_year += 1900;

	/* now get the time */
	p = cpstr(p, buf);
	input_time.tm_hour = atoi(buf);
	p = cpstr(p, buf);
	input_time.tm_min = atoi(buf);
	p = cpstr(p, buf);
	input_time.tm_sec = atoi(buf);

	/* use mktime(), but make this GMT, not local time */
	result = mktime(&input_time);
#endif

	result = nabstimein((char *) timestamp_str);

	return result;
}

char	   *
timestamp_out(time_t timestamp)
{
	char	   *result;
	int			tz;
	double		fsec = 0;
	struct tm	tt,
			   *tm = &tt;
	char		buf[MAXDATELEN + 1];
	char		zone[MAXDATELEN + 1],
			   *tzn = zone;

#if FALSE
	time = localtime(&timestamp);

	sprintf(result, "%04d-%02d-%02d %02d:%02d:%02d",
			time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
			time->tm_hour, time->tm_min, time->tm_sec);
#endif
	abstime2tm(timestamp, &tz, tm, tzn);
	EncodeDateTime(tm, fsec, &tz, &tzn, USE_ISO_DATES, buf);

	result = palloc(strlen(buf) + 1);
	strcpy(result, buf);
	return result;
}

time_t
now(void)
{
	time_t		sec;

	time(&sec);
	return (sec);
}

bool
timestampeq(time_t t1, time_t t2)
{
	return difftime(t1, t2) == 0;
}

bool
timestampne(time_t t1, time_t t2)
{
	return difftime(t1, t2) != 0;
}

bool
timestamplt(time_t t1, time_t t2)
{
	return difftime(t1, t2) > 0;
}

bool
timestampgt(time_t t1, time_t t2)
{
	return difftime(t1, t2) < 0;
}

bool
timestample(time_t t1, time_t t2)
{
	return difftime(t1, t2) >= 0;
}

bool
timestampge(time_t t1, time_t t2)
{
	return difftime(t1, t2) <= 0;
}

DateTime   *
timestamp_datetime(time_t timestamp)
{
	DateTime   *result;

	double		fsec = 0;
	struct tm  *tm;

	if (!PointerIsValid(result = PALLOCTYPE(DateTime)))
		elog(WARN, "Memory allocation failed, can't convert timestamp to datetime", NULL);

	tm = localtime((time_t *) &timestamp);
	tm->tm_year += 1900;
	tm->tm_mon += 1;

	if (tm2datetime(tm, fsec, NULL, result) != 0)
		elog(WARN, "Unable to convert timestamp to datetime", timestamp_out(timestamp));

	return (result);
}								/* timestamp_datetime() */