/*
 * Copyright 2024 Vsevolod Stakhov
 *
 * 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.
 */
#include "fstring.h"
#include "str_util.h"
#include "contrib/fastutf8/fastutf8.h"
#include "contrib/mumhash/mum.h"


#ifdef WITH_JEMALLOC
#include <jemalloc/jemalloc.h>
#if (JEMALLOC_VERSION_MAJOR == 3 && JEMALLOC_VERSION_MINOR >= 6) || (JEMALLOC_VERSION_MAJOR > 3)
#define HAVE_MALLOC_SIZE 1
#define sys_alloc_size(sz) nallocx(sz, 0)
#endif
#elif defined(__APPLE__)
#include <malloc/malloc.h>
#define HAVE_MALLOC_SIZE 1
#define sys_alloc_size(sz) malloc_good_size(sz)
#endif

static const gsize default_initial_size = 16;

#define fstravail(s) ((s)->allocated - (s)->len)

rspamd_fstring_t *
rspamd_fstring_new(void)
{
	rspamd_fstring_t *s;

	if ((s = malloc(default_initial_size + sizeof(*s))) == NULL) {
		g_error("%s: failed to allocate %" G_GSIZE_FORMAT " bytes",
				G_STRLOC, default_initial_size + sizeof(*s));

		return NULL;
	}

	s->len = 0;
	s->allocated = default_initial_size;

	return s;
}

rspamd_fstring_t *
rspamd_fstring_sized_new(gsize initial_size)
{
	rspamd_fstring_t *s;
	gsize real_size = MAX(default_initial_size, initial_size);

	if ((s = malloc(real_size + sizeof(*s))) == NULL) {
		g_error("%s: failed to allocate %" G_GSIZE_FORMAT " bytes",
				G_STRLOC, real_size + sizeof(*s));

		return NULL;
	}
	s->len = 0;
	s->allocated = real_size;

	return s;
}

rspamd_fstring_t *
rspamd_fstring_new_init(const char *init, gsize len)
{
	rspamd_fstring_t *s;
	gsize real_size = MAX(default_initial_size, len);

	if ((s = malloc(real_size + sizeof(*s))) == NULL) {
		g_error("%s: failed to allocate %" G_GSIZE_FORMAT " bytes",
				G_STRLOC, real_size + sizeof(*s));

		abort();
	}

	s->len = len;
	s->allocated = real_size;
	memcpy(s->str, init, len);

	return s;
}

rspamd_fstring_t *
rspamd_fstring_assign(rspamd_fstring_t *str, const char *init, gsize len)
{
	gsize avail;

	if (str == NULL) {
		return rspamd_fstring_new_init(init, len);
	}

	avail = fstravail(str);

	if (avail < len) {
		str = rspamd_fstring_grow(str, len);
	}

	if (len > 0) {
		memcpy(str->str, init, len);
	}

	str->len = len;

	return str;
}

void rspamd_fstring_free(rspamd_fstring_t *str)
{
	free(str);
}

inline gsize
rspamd_fstring_suggest_size(gsize len, gsize allocated, gsize needed_len)
{
	gsize newlen, optlen = 0;

	if (allocated < 4096) {
		newlen = MAX(len + needed_len, allocated * 2);
	}
	else {
		newlen = MAX(len + needed_len, 1 + allocated * 3 / 2);
	}

#ifdef HAVE_MALLOC_SIZE
	optlen = sys_alloc_size(newlen + sizeof(rspamd_fstring_t));
#endif

	return MAX(newlen, optlen);
}

rspamd_fstring_t *
rspamd_fstring_grow(rspamd_fstring_t *str, gsize needed_len)
{
	gsize newlen;
	gpointer nptr;

	newlen = rspamd_fstring_suggest_size(str->len, str->allocated, needed_len);

	nptr = realloc(str, newlen + sizeof(*str));

	if (nptr == NULL) {
		/* Avoid memory leak */
		free(str);
		g_error("%s: failed to re-allocate %" G_GSIZE_FORMAT " bytes",
				G_STRLOC, newlen + sizeof(*str));
		abort();
	}

	str = nptr;
	str->allocated = newlen;

	return str;
}

rspamd_fstring_t *
rspamd_fstring_append(rspamd_fstring_t *str, const char *in, gsize len)
{
	if (str == NULL) {
		str = rspamd_fstring_new_init(in, len);
	}
	else {
		gsize avail = fstravail(str);

		if (avail < len) {
			str = rspamd_fstring_grow(str, len);
		}

		memcpy(str->str + str->len, in, len);
		str->len += len;
	}

	return str;
}

rspamd_fstring_t *
rspamd_fstring_append_chars(rspamd_fstring_t *str,
							char c, gsize len)
{
	if (str == NULL) {
		str = rspamd_fstring_sized_new(len);

		memset(str->str + str->len, c, len);
		str->len += len;
	}
	else {
		gsize avail = fstravail(str);

		if (avail < len) {
			str = rspamd_fstring_grow(str, len);
		}

		memset(str->str + str->len, c, len);
		str->len += len;
	}

	return str;
}

void rspamd_fstring_erase(rspamd_fstring_t *str, gsize pos, gsize len)
{
	if (pos < str->len) {
		if (pos + len > str->len) {
			len = str->len - pos;
		}

		if (len == str->len - pos) {
			/* Fast path */
			str->len = pos;
		}
		else {
			memmove(str->str + pos, str->str + pos + len, str->len - pos);
			str->len -= pos;
		}
	}
	else {
		/* Do nothing */
	}
}

/* Compat code */
static uint64_t
fstrhash_c(uint64_t c, uint64_t hval)
{
	return mum_hash_step(hval, c);
}


/*
 * Return hash value for a string
 */
uint32_t
rspamd_fstrhash_lc(const rspamd_ftok_t *str, gboolean is_utf)
{
	uint64_t hval;
	const char *p;

	if (str == NULL) {
		return 0;
	}

	p = str->begin;
	hval = str->len;

	if (is_utf) {
		if (rspamd_fast_utf8_validate(p, str->len) != 0) {
			return rspamd_fstrhash_lc(str, FALSE);
		}

		size_t i = 0, len = str->len;
		UChar32 uc;

		while (i < len) {
			U8_NEXT(p, i, len, uc);

			if (uc > 0) {
				hval = fstrhash_c(u_tolower(uc), hval);
			}
		}
	}
	else {
		gsize large_steps = str->len / sizeof(uint64_t);
		for (size_t i = 0; i < large_steps; i++, p += sizeof(uint64_t)) {
			/* Copy to the uint64 lowercasing each byte */
			union {
				char c[sizeof(uint64_t)];
				uint64_t iu64;
			} t;
			for (int j = 0; j < sizeof(uint64_t); j++) {
				t.c[j] = g_ascii_tolower(p[j]);
			}
			hval = fstrhash_c(t.iu64, hval);
		}

		gsize remain = str->len % sizeof(uint64_t);
		for (size_t i = 0; i < remain; i++, p++) {
			hval = fstrhash_c(g_ascii_tolower(*p), hval);
		}
	}

	return hval;
}

gboolean
rspamd_fstring_equal(const rspamd_fstring_t *s1,
					 const rspamd_fstring_t *s2)
{
	g_assert(s1 != NULL && s2 != NULL);

	if (s1->len == s2->len) {
		return (memcmp(s1->str, s2->str, s1->len) == 0);
	}

	return FALSE;
}

int rspamd_fstring_casecmp(const rspamd_fstring_t *s1,
						   const rspamd_fstring_t *s2)
{
	int ret = 0;

	g_assert(s1 != NULL && s2 != NULL);

	if (s1->len == s2->len) {
		ret = rspamd_lc_cmp(s1->str, s2->str, s1->len);
	}
	else {
		ret = s1->len - s2->len;
	}

	return ret;
}

int rspamd_fstring_cmp(const rspamd_fstring_t *s1,
					   const rspamd_fstring_t *s2)
{
	g_assert(s1 != NULL && s2 != NULL);

	if (s1->len == s2->len) {
		return memcmp(s1->str, s2->str, s1->len);
	}

	return s1->len - s2->len;
}

int rspamd_ftok_casecmp(const rspamd_ftok_t *s1,
						const rspamd_ftok_t *s2)
{
	int ret = 0;

	g_assert(s1 != NULL && s2 != NULL);

	if (s1->len == s2->len) {
		ret = rspamd_lc_cmp(s1->begin, s2->begin, s1->len);
	}
	else {
		ret = s1->len - s2->len;
	}

	return ret;
}

int rspamd_ftok_cmp(const rspamd_ftok_t *s1,
					const rspamd_ftok_t *s2)
{
	g_assert(s1 != NULL && s2 != NULL);

	if (s1->len == s2->len) {
		return memcmp(s1->begin, s2->begin, s1->len);
	}

	return s1->len - s2->len;
}

gboolean
rspamd_ftok_starts_with(const rspamd_ftok_t *s1,
						const rspamd_ftok_t *s2)
{
	g_assert(s1 != NULL && s2 != NULL);

	if (s1->len >= s2->len) {
		return !!(memcmp(s1->begin, s2->begin, s2->len) == 0);
	}

	return FALSE;
}

void rspamd_fstring_mapped_ftok_free(gpointer p)
{
	rspamd_ftok_t *tok = p;
	rspamd_fstring_t *storage;

	storage = (rspamd_fstring_t *) (tok->begin - 2 * sizeof(gsize));
	rspamd_fstring_free(storage);
	g_free(tok);
}

rspamd_ftok_t *
rspamd_ftok_map(const rspamd_fstring_t *s)
{
	rspamd_ftok_t *tok;

	g_assert(s != NULL);

	tok = g_malloc(sizeof(*tok));
	tok->begin = s->str;
	tok->len = s->len;

	return tok;
}

char *
rspamd_fstring_cstr(const rspamd_fstring_t *s)
{
	char *result;

	if (s == NULL) {
		return NULL;
	}

	result = g_malloc(s->len + 1);
	memcpy(result, s->str, s->len);
	result[s->len] = '\0';

	return result;
}

char *
rspamd_ftok_cstr(const rspamd_ftok_t *s)
{
	char *result;

	if (s == NULL) {
		return NULL;
	}

	result = g_malloc(s->len + 1);
	memcpy(result, s->begin, s->len);
	result[s->len] = '\0';

	return result;
}

gboolean
rspamd_ftok_cstr_equal(const rspamd_ftok_t *s, const char *pat,
					   gboolean icase)
{
	gsize slen;
	rspamd_ftok_t srch;

	g_assert(s != NULL);
	g_assert(pat != NULL);

	slen = strlen(pat);
	srch.begin = pat;
	srch.len = slen;

	if (icase) {
		return (rspamd_ftok_casecmp(s, &srch) == 0);
	}

	return (rspamd_ftok_cmp(s, &srch) == 0);
}

char *
rspamd_ftokdup(const rspamd_ftok_t *src)
{
	char *newstr;

	if (src == NULL) {
		return NULL;
	}

	newstr = g_malloc(src->len + 1);
	memcpy(newstr, src->begin, src->len);
	newstr[src->len] = '\0';

	return newstr;
}

char *
rspamd_fstringdup(const rspamd_fstring_t *src)
{
	char *newstr;

	if (src == NULL) {
		return NULL;
	}

	newstr = g_malloc(src->len + 1);
	memcpy(newstr, src->str, src->len);
	newstr[src->len] = '\0';

	return newstr;
}