/*
 * Copyright (C) 2018, 2019 "IoT.bzh"
 * Author: José Bollo <jose.bollo@iot.bzh>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define _GNU_SOURCE

#include <ctype.h>

#include "globmatch.h"

/**
 * Matches whether the string 'str' matches the pattern 'pat'
 * and returns its matching score.
 *
 * @param pat the glob pattern
 * @param str the string to match
 * @return 0 if no match or number representing the matching score
 */
static unsigned match(const char *pat, const char *str, int flags)
{
	unsigned r, rs, rr;
	char c, x;
	int eq;

	/* scan the prefix without glob */
	r = 1;
	while ((c = *pat++) != GLOB) {
		x = *str++;
		eq = (flags & FNM_CASEFOLD) ? (tolower(c) == tolower(x)) : (c == x);
		if (!eq)
			return 0; /* no match */
		if (!c)
			return r; /* match up to end */
		r++;
	}

	/* glob found */
	c = *pat++;
	if (!c) {
		/* not followed by pattern */
		if (flags & FNM_PATHNAME) {
			while(*str)
				if (*str++ == '/')
					return 0;
		}
		return r;
	}

	/* evaluate the best score for following pattern */
	rs = 0;
	while (*str) {
		x = *str++;
		eq = (flags & FNM_CASEFOLD) ? (tolower(c) == tolower(x)) : (c == x);
		if (eq) {
			/* first char matches, check remaining string */
			rr = match(pat, str, flags);
			if (rr > rs)
				rs = rr;
		} else if ((flags & FNM_PATHNAME) && x == '/')
			return 0;
	}

	/* best score or not match if rs == 0 */
	return rs ? rs + r : 0;
}

/**
 * Matches whether the string 'str' matches the pattern 'pat'
 * and returns its matching score.
 *
 * @param pat the glob pattern
 * @param str the string to match
 * @return 0 if no match or number representing the matching score
 */
unsigned globmatch(const char *pat, const char *str)
{
	return match(pat, str, 0);
}

/**
 * Matches whether the string 'str' matches the pattern 'pat'
 * and returns its matching score.
 *
 * @param pat the glob pattern
 * @param str the string to match
 * @return 0 if no match or number representing the matching score
 */
unsigned globmatchi(const char *pat, const char *str)
{
	return match(pat, str, FNM_CASEFOLD);
}

#if !WITH_FNMATCH
int fnmatch(const char *pattern, const char *string, int flags)
{
	return !match(pattern, string, flags);
}
#endif