/*
 * Copyright (C) 2018-2022 Intel Corporation.
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <string.h>
#include <errno.h>
#include <regex.h>
#include <stdarg.h>
#include <stdlib.h>
#include "log_sys.h"
#include "fsutils.h"

/**
 * Find the first line containing specified string in given area.
 *
 * @param str A pointer to the string contained by target line.
 * @param str_size String length of str.
 * @param area A pointer to the area where target line may be located.
 *             This pointer will be returned if the specified string is in
 *             the first line of area (There is not '\n' located between area
 *             and the head of searched string).
 * @param area_size String length of area.
 * @param search_from A pointer where searching starts. It should be greater
 *                    than or equal to area, and less than area + area_size.
 * @param[out] len The length of target line (excludes \n), it only be modified
 *             when function returns successfully.
 *
 * @return a pointer to the head of target line within area (it may be greater
 *         than search_from).
 *         NULL will be returned if the specified string is not found in
 *         any lines (lines must end with '\n'. It means the real searching
 *         scope is from search_from to the last '\n' in area).
 */
char *get_line(const char *str, size_t str_size,
		const char *area, size_t area_size,
		const char *search_from, size_t *len)
{
	char *p;
	char *match;
	char *tail;
	ssize_t search_size = area + area_size - search_from;

	if (!str || !str_size || !area || !area_size || !search_from || !len)
		return NULL;

	if (search_from < area || search_from >= area + area_size ||
	    (size_t)search_size < str_size)
		return NULL;

	match = memmem(search_from, search_size, str, str_size);
	if (!match)
		return NULL;
	tail = memchr(match + str_size, '\n',
		      area + area_size - match - str_size);
	if (!tail)
		return NULL;

	for (p = match; p >= area; p--) {
		if (*p == '\n') {
			*len = tail - p - 1;
			return (char *)(p + 1);
		}
	}

	*len = tail - area;
	return (char *)area;
}

/**
 * Get the length of line.
 *
 * @param str Start address of line.
 * @param size Size of searched space.
 *
 * @return the length of line (excludes \n) if successful, or -1 if not.
 *	   This function return -1 if string doesn't contain \n.
 */
ssize_t strlinelen(const char *str, size_t size)
{
	char *tail;

	if (!str)
		return -1;

	tail = memchr(str, '\n', size);
	if (tail)
		return tail - str;

	return -1;
}

/**
 * Find the last occurrence of the substring str in the string s.
 *
 * @param s Range of search.
 * @param substr String to be found.
 *
 * @return a pointer to the beginning of the substring,
 *	   or NULL if the substring is not found.
 */
char *strrstr(const char *s, const char *substr)
{
	const char *found;
	const char *p = s;

	while ((found = strstr(p, substr)))
		p = found + 1;

	if (p != s)
		return (char *)(p - 1);

	return NULL;
}

char *strtrim(char *str, size_t len)
{
	size_t h_del = 0;
	size_t reserve;
	char *p;

	if (!len)
		return str;

	for (p = str; p < str + len && *p == ' '; p++)
		h_del++;

	reserve = len - h_del;
	if (!reserve) {
		*str = '\0';
		return str;
	}

	for (p = str + len - 1; p >= str && *p == ' '; p--)
		reserve--;

	memmove(str, str + h_del, reserve);
	*(str + reserve) = '\0';
	return str;
}

int strcnt(char *str, char c)
{
	int cnt = 0;
	char *p = str;
	char *found;

	if (!str)
		return -EINVAL;

	while ((found = strchr(p, c))) {
		p = found + 1;
		cnt++;
	}

	return cnt;
}

char *strings_ind(char *strings, size_t size, int index, size_t *slen)
{
	int i = 0;
	size_t len;
	char *start = strings;
	char *str_tail;
	size_t left;

	if (!strings || !size)
		return NULL;

	str_tail = memchr((void *)strings, '\0', size);
	if (!str_tail)
		return NULL;

	while (1) {
		len = str_tail - start;
		if (i++ == index)
			break;
		left = strings + size - str_tail - 1;
		if (!left)
			return NULL;
		start = str_tail + 1;
		str_tail = memchr((void *)start, '\0', left);
		if (!str_tail)
			break;
	}

	if (slen)
		*slen = len;
	return start;
}

static int reg_match(const char *str, const char *pattern,
		char *matched_sub, size_t matched_space,
		size_t *end_off)
{
	int err;
	regex_t reg;
	char err_msg[128];
	regmatch_t pm[1];
	size_t matched_len;

	LOGD("reg: %s\n", pattern);
	err = regcomp(&reg, pattern, REG_EXTENDED);
	if (err) {
		regerror(err, &reg, err_msg, sizeof(err_msg));
		LOGE("failed to regcomp - %s\n", err_msg);
		return -1;
	}

	err = regexec(&reg, str, sizeof(pm)/sizeof(regmatch_t), pm, 0);
	regfree(&reg);
	if (err == REG_NOMATCH) {
		LOGE("failed to match with reg (%s) str (%s)\n", pattern, str);
		return -1;
	}
	if (pm[0].rm_so == -1)
		return -1;

	*end_off = pm[0].rm_eo;
	if (matched_space == 0 || matched_sub == NULL)
		/* get offset only */
		return 0;

	matched_len = pm[0].rm_eo - pm[0].rm_so;
	*(char *)mempcpy(matched_sub, str + pm[0].rm_so,
			 MIN(matched_len, matched_space - 1)) = '\0';
	return 0;
}

static char *exp_end(const char *fmt, size_t flen, const char *exp_s)
{
	/* supports %[regex..] and %*[regex..] */
	int flag = 0;
	const char *p;

	if (exp_s < fmt || exp_s >= fmt + flen)
		return NULL;

	for (p = exp_s; p < fmt + flen; p++) {
		if (*p == '[')
			flag++;

		if (*p == ']') {
			flag--;
			if (flag == 0)
				return (char *)(p + 1);
			else if (flag < 0)
				return NULL;
		}
	}
	return NULL;
}

static int exp2reg(const char *s, const char *e, int *ignore_flag, char **reg)
{
	const char *oreg_s;
	int flag_tmp;
	char *buf;

	if (memcmp(s, "%*[", 3) == 0) {
		flag_tmp = 1;
		oreg_s = s + 3;
	} else if (memcmp(s, "%[", 2) == 0) {
		flag_tmp = 0;
		oreg_s = s + 2;
	} else {
		LOGE("invalid exp - exp must start with \"%%[\" or \"%%*[\"\n");
		return -1;
	}

	if (oreg_s >= e) {
		LOGE("invalid exp - exp empty\n");
		return -1;
	}

	buf = malloc(e - oreg_s + 1);
	if (!buf) {
		LOGE("out-of-mem\n");
		return -1;
	}

	buf[0] = '^';
	memcpy(&buf[1], oreg_s, e - oreg_s - 1);
	buf[e - oreg_s] = '\0';

	*reg = buf;
	*ignore_flag = flag_tmp;
	return 0;
}

int str_split_ere(const char *str, size_t slen,
		const char *fmt, size_t flen, ...)
{
	va_list v;
	char *_str, *_fmt;
	const char *exp_s, *exp_e;
	int ignore_flag;
	char *reg;
	size_t str_off = 0;
	size_t off;
	char *sreq;
	size_t sreqsize;
	int ret = 0;

	if (!str || !slen || !fmt || !flen)
		return ret;

	_str = strndup(str, slen);
	if (!_str)
		return ret;
	_fmt = strndup(fmt, flen);
	if (!_fmt) {
		free(_str);
		return ret;
	}

	va_start(v, flen);
	/* supports %[regex..] and %*[regex..] */
	exp_s = _fmt;
	while (str_off < slen && *exp_s) {
		exp_e = exp_end(_fmt, flen, exp_s);
		if (!exp_e) {
			LOGE("invalid exp - failed to find the end of exp\n");
			goto out;
		}

		if (exp2reg(exp_s, exp_e, &ignore_flag, &reg) == -1) {
			LOGE("failed to translate exp to reg\n");
			goto out;
		}

		if (ignore_flag == 1) {
			sreq = NULL;
			sreqsize = 0;
		} else {
			sreq = va_arg(v, char *);
			sreqsize = va_arg(v, size_t);
		}

		if (reg_match(_str + str_off, reg, sreq, sreqsize,
			      &off) == -1) {
			LOGE("failed to match reg\n");
			free(reg);
			goto out;
		} else {
			if (ignore_flag == 0)
				ret++;
		}

		exp_s = exp_e;
		str_off += off;
		free(reg);
	}

out:
	va_end(v);
	free(_str);
	free(_fmt);
	return ret;
}