/*
 *	aegis - project change supervisor
 *	Copyright (C) 2002, 2003 Peter Miller;
 *	All rights reserved.
 *
 *	This program 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; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This program 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, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * MANIFEST: functions to manipulate dates
 */

#include <language.h>
#include <now.h>
#include <sub.h>
#include <sub/date.h>
#include <trace.h>
#include <wstr.h>
#include <wstr_list.h>


/*
 * NAME
 *	sub_date - the date substitution
 *
 * SYNOPSIS
 *	wstring_ty *sub_date(wstring_list_ty *arg);
 *
 * DESCRIPTION
 *	The sub_date function implements the date substitution.
 *	The date substitution is replaced by the current date.
 *	The optional arguments may construct format string,
 *	similar to the date(1) command.
 *
 * ARGUMENTS
 *	arg	- list of arguments, including the function name as [0]
 *
 * RETURNS
 *	a pointer to a string in dynamic memory;
 *	or NULL on error, setting suberr appropriately.
 */

wstring_ty *
sub_date(sub_context_ty *scp, wstring_list_ty *arg)
{
    wstring_ty	    *result;
    time_t	    when;

    trace(("sub_date()\n{\n"));
    when = now();
    if (arg->nitems < 2)
    {
	char		*time_string;

	time_string = ctime(&when);
	result = wstr_n_from_c(time_string, 24);
    }
    else
    {
	struct tm	*theTm;
	char		buf[1000];
	size_t		nbytes;
	wstring_ty	*wfmt;
	string_ty	*fmt;

	wfmt = wstring_list_to_wstring(arg, 1, 32767, (char *)0);
	fmt = wstr_to_str(wfmt);
	wstr_free(wfmt);
	theTm = localtime(&when);

	/*
	 * The strftime is locale dependent.
	 */
	language_human();
	nbytes = strftime(buf, sizeof(buf) - 1, fmt->str_text, theTm);
	language_C();

	if (!nbytes && fmt->str_length)
	{
	    sub_context_error_set(scp, i18n("strftime output too large"));
	    result = 0;
	}
	else
	    result = wstr_n_from_c(buf, nbytes);
	str_free(fmt);
    }
    trace(("return %8.8lX;\n", (long)result));
    trace(("}\n"));
    return result;
}
