/*!
 * When looking up extensions, we can have different requests
 * identified by the 'action' argument, as follows.
 * Note that the coding is such that the low 4 bits are the
 * third argument to extension_match_core.
 */
enum ext_match_t {
	E_MATCHMORE = 	0x00,	/* extension can match but only with more 'digits' */
	E_CANMATCH =	0x01,	/* extension can match with or without more 'digits' */
	E_MATCH =	0x02,	/* extension is an exact match */
	E_MATCH_MASK =	0x03,	/* mask for the argument to extension_match_core() */
	E_SPAWN =	0x12,	/* want to spawn an extension. Requires exact match */
	E_EXEC =	0x22,	/* want to exec an extension. Requires exact match */
	E_FINDLABEL =	0x32	/* returns the priority for a given label. Requires exact match */
};

/*
 * Internal function for ast_extension_{match|close}
 * return 0 on no-match, 1 on match, 2 on early match.
 * mode is as follows:
 *	E_MATCH		success only on exact match
 *	E_MATCHMORE	success only on partial match (i.e. leftover digits in pattern)
 *	E_CANMATCH	either of the above.
 */
static int extension_match_core(const char *pattern, const char *data, enum ext_match_t mode)
{
	mode &= E_MATCH_MASK;	/* only consider the relevant bits */

	if (pattern[0] != '_') { /* not a pattern, try exact or partial match */
		int ld = strlen(data), lp = strlen(pattern);

		if (lp < ld)		/* pattern too short, cannot match */
			return 0;
		/* depending on the mode, accept full or partial match or both */
		if (mode == E_MATCH)
			return !strcmp(pattern, data); /* 1 on match, 0 on fail */
		if (ld == 0 || !strncasecmp(pattern, data, ld)) /* partial or full match */
			return (mode == E_MATCHMORE) ? lp > ld : 1; /* XXX should consider '!' and '/' ? */
		else
			return 0;
	}
	pattern++; /* skip leading _ */
	while (*data && *pattern && *pattern != '/') {
		const char *end;

		if (*data == '-') { /* skip '-' in data (just a separator) */
			data++;	
			continue;
		}
		switch (toupper(*pattern)) {
		case '[':	/* a range */
			end = strchr(pattern+1, ']'); /* XXX should deal with escapes ? */
			if (end == NULL) {
				ast_log(LOG_WARNING, "Wrong usage of [] in the extension\n");
				return 0;	/* unconditional failure */
			}
			for (pattern++; pattern != end; pattern++) {
				if (pattern+2 < end && pattern[1] == '-') { /* this is a range */
					if (*data >= pattern[0] && *data <= pattern[2])
						break;	/* match found */
					else {
						pattern += 2; /* skip a total of 3 chars */
						continue;
					}
				} else if (*data == pattern[0])
					break;	/* match found */
			}
			if (pattern == end)
				return 0;
			pattern = end;	/* skip and continue */
			break;
		case 'N':
			if (*data < '2' || *data > '9')
				return 0;
			break;
		case 'X':
			if (*data < '0' || *data > '9')
				return 0;
			break;
		case 'Z':
			if (*data < '1' || *data > '9')
				return 0;
			break;
		case '.':	/* Must match, even with more digits */
			return 1;
		case '!':	/* Early match */
			return 2;
		case ' ':
		case '-':	/* Ignore these in patterns */
			data--; /* compensate the final data++ */
			break;
		default:
			if (*data != *pattern)
				return 0;
		}
		data++;
		pattern++;
	}
	if (*data)			/* data longer than pattern, no match */
		return 0;
	/*
	 * match so far, but ran off the end of the data.
	 * Depending on what is next, determine match or not.
	 */
	if (*pattern == '\0' || *pattern == '/')	/* exact match */
		return (mode == E_MATCHMORE) ? 0 : 1;	/* this is a failure for E_MATCHMORE */
	else if (*pattern == '!')			/* early match */
		return 2;
	else						/* partial match */
		return (mode == E_MATCH) ? 0 : 1;	/* this is a failure for E_MATCH */
}

int ast_extension_match(const char *pattern, const char *data)
{
	return extension_match_core(pattern, data, E_MATCH);
}

int ast_extension_close(const char *pattern, const char *data, int needmore)
{
	if (needmore != E_MATCHMORE && needmore != E_CANMATCH)
		ast_log(LOG_WARNING, "invalid argument %d\n", needmore);
	return extension_match_core(pattern, data, needmore);
}