/*
 *	aegis - project change supervisor
 *	Copyright (C) 1999 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 substitutes
 */

#include <sub.h>
#include <sub/substitute.h>
#include <trace.h>
#include <wstr_list.h>


static string_ty	*gerr;
static sub_context_ty	*gscp;


static void err _((const char *));

static void
err(message)
	const char	*message;
{
	if (gerr)
		str_free(gerr);
	gerr = str_from_c(message);
	sub_context_error_set(gscp, gerr->str_text);
}


wstring_ty *
sub_substitute(scp, arg)
	sub_context_ty	*scp;
	wstring_list_ty	*arg;
{
	string_ty	*s;
	string_ty	*lhs;
	string_ty	*rhs;
	string_ty	*rs;
	wstring_ty	*ws;
	wstring_ty	*result;

	/*
	 * make sure there are enough arguments
	 */
	trace(("sub_substitute()\n{\n"));
	if (arg->nitems < 3)
	{
		sub_context_error_set(scp, i18n("requires two or more arguments"));
		trace(("return NULL;\n"));
		trace(("}\n"));
		return 0;
	}
	lhs = wstr_to_str(arg->item[1]);
	rhs = wstr_to_str(arg->item[2]);

	/*
	 * turn it into one big string to be substituted within
	 */
	ws = wstring_list_to_wstring(arg, (size_t)3, arg->nitems, (char *)0);
	s = wstr_to_str(ws);
	wstr_free(ws);

	/*
	 * do the substitution
	 */
	gscp = scp;
	rs = str_re_substitute(lhs, rhs, s, err, 32767);
	gscp = 0;
	result = rs ? str_to_wstr(rs) : 0;

	/*
	 * clean up and return
	 */
	str_free(lhs);
	str_free(rhs);
	str_free(s);
	str_free(rs);
	trace(("return %8.8lX;\n", (long)result));
	trace(("}\n"));
	return result;
}