/*
 * Copyright 2007 Rob Kendrick <rjek@netsurf-browser.org>
 * Copyright 2004-2007 James Bursa <bursa@users.sourceforge.net>
 * Copyright 2003 Phil Mellor <monkeyson@users.sourceforge.net>
 * Copyright 2003 John M Bell <jmb202@ecs.soton.ac.uk>
 * Copyright 2004 John Tytgat <joty@netsurf-browser.org>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * \file utils/time.c
 * \brief Implementation of time operations.
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

#include <curl/curl.h>

#include "utils/errors.h"
#include "utils/time.h"



/**
 * Weekdays
 *
 * Must be calender order.
 */
enum nsc_time_weekdays {
	NSC_TIME_WEEKDAY_SUN,
	NSC_TIME_WEEKDAY_MON,
	NSC_TIME_WEEKDAY_TUE,
	NSC_TIME_WEEKDAY_WED,
	NSC_TIME_WEEKDAY_THU,
	NSC_TIME_WEEKDAY_FRI,
	NSC_TIME_WEEKDAY_SAT,
	NSC_TIME_WEEKDAY__COUNT
};
/**
 * Months
 *
 * Must be calender order.
 */
enum nsc_time_months {
	NSC_TIME_MONTH_JAN,
	NSC_TIME_MONTH_FEB,
	NSC_TIME_MONTH_MAR,
	NSC_TIME_MONTH_APR,
	NSC_TIME_MONTH_MAY,
	NSC_TIME_MONTH_JUN,
	NSC_TIME_MONTH_JUL,
	NSC_TIME_MONTH_AUG,
	NSC_TIME_MONTH_SEP,
	NSC_TIME_MONTH_OCT,
	NSC_TIME_MONTH_NOV,
	NSC_TIME_MONTH_DEC,
	NSC_TIME_MONTH__COUNT,
};


/**
 * Array of short weekday names.
 */
static const char * const weekdays_short[NSC_TIME_WEEKDAY__COUNT] = {
	[NSC_TIME_WEEKDAY_SUN] = "Sun",
	[NSC_TIME_WEEKDAY_MON] = "Mon",
	[NSC_TIME_WEEKDAY_TUE] = "Tue",
	[NSC_TIME_WEEKDAY_WED] = "Wed",
	[NSC_TIME_WEEKDAY_THU] = "Thu",
	[NSC_TIME_WEEKDAY_FRI] = "Fri",
	[NSC_TIME_WEEKDAY_SAT] = "Sat"
};
/**
 * Array of month names.
 */
static const char * const months[NSC_TIME_MONTH__COUNT] = {
	[NSC_TIME_MONTH_JAN] = "Jan",
	[NSC_TIME_MONTH_FEB] = "Feb",
	[NSC_TIME_MONTH_MAR] = "Mar",
	[NSC_TIME_MONTH_APR] = "Apr",
	[NSC_TIME_MONTH_MAY] = "May",
	[NSC_TIME_MONTH_JUN] = "Jun",
	[NSC_TIME_MONTH_JUL] = "Jul",
	[NSC_TIME_MONTH_AUG] = "Aug",
	[NSC_TIME_MONTH_SEP] = "Sep",
	[NSC_TIME_MONTH_OCT] = "Oct",
	[NSC_TIME_MONTH_NOV] = "Nov",
	[NSC_TIME_MONTH_DEC] = "Dec"
};


/* exported interface documented in utils/time.h */
const char *rfc1123_date(time_t t)
{
	static char ret[30];

	struct tm *tm = gmtime(&t);

	snprintf(ret, sizeof ret, "%s, %02d %s %d %02d:%02d:%02d GMT",
			weekdays_short[tm->tm_wday], tm->tm_mday,
			months[tm->tm_mon], tm->tm_year + 1900,
			tm->tm_hour, tm->tm_min, tm->tm_sec);

	return ret;
}


/* exported function documented in utils/time.h */
int nsc_sntimet(char *str, size_t size, time_t *timep)
{
#ifndef HAVE_STRFTIME
	long long val;
	val = (long long)*timep;

	return snprintf(str, size, "%lld", val);
#else
	struct tm *ltm;

	ltm = localtime(timep);
	if (ltm == NULL) {
		return -1;
	}

	return strftime(str, size, "%s", ltm);
#endif
}


/* exported function documented in utils/time.h */
nserror nsc_snptimet(const char *str, size_t size, time_t *timep)
{
	time_t time_out;

#ifndef HAVE_STRPTIME
	char *rstr;

	if (size < 1) {
		return NSERROR_BAD_PARAMETER;
	}

	errno = 0;
	time_out = (time_t)strtoll(str, &rstr, 10);

	/* The conversion may have a range faliure or no digits were found */
	if ((errno != 0) || (rstr == str)) {
		return NSERROR_BAD_PARAMETER;
	}

#else
	struct tm ltm;

	if (size < 1) {
		return NSERROR_BAD_PARAMETER;
	}

	if (strptime(str, "%s", &ltm) == NULL) {
		return NSERROR_BAD_PARAMETER;
	}

	time_out = mktime(&ltm);

#endif
	*timep = time_out;

	return NSERROR_OK;
}


/* exported function documented in utils/time.h */
nserror nsc_strntimet(const char *str, size_t size, time_t *timep)
{
	time_t result;

	result = curl_getdate(str, NULL);

	if (result == -1) {
		return NSERROR_INVALID;
	}

	*timep = result;

	return NSERROR_OK;
}