/*
 * 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.
 */

#ifndef RSPAMD_FUZZY_STORAGE_H
#define RSPAMD_FUZZY_STORAGE_H

#include "config.h"
#include "rspamd.h"
#include "shingles.h"
#include "cryptobox.h"

#ifdef __cplusplus
extern "C" {
#endif

#define RSPAMD_FUZZY_VERSION 4
#define RSPAMD_FUZZY_KEYLEN 8

#define RSPAMD_FUZZY_FLAG_WEAK (1u << 7u)
/* Use lower 4 bits for the version */
#define RSPAMD_FUZZY_VERSION_MASK 0x0fu
/* Capability bit: client supports v2 (multi-flag) replies */
#define RSPAMD_FUZZY_V2_CAP (1u << 4u)
/* Commands for fuzzy storage */
#define FUZZY_CHECK 0
#define FUZZY_WRITE 1
#define FUZZY_DEL 2
#define FUZZY_STAT 3
#define FUZZY_PING 4
#define FUZZY_CLIENT_MAX 4
/* Internal commands */
#define FUZZY_REFRESH 100 /* Update expire */
#define FUZZY_DUP 101     /* Skip duplicate in update queue */

/**
 * The epoch of the fuzzy client
 */
enum rspamd_fuzzy_epoch {
	RSPAMD_FUZZY_EPOCH10, /**< 1.0+ encryption */
	RSPAMD_FUZZY_EPOCH11, /**< 1.7+ extended reply */
	RSPAMD_FUZZY_EPOCH12, /**< multi-flag reply */
	RSPAMD_FUZZY_EPOCH_MAX
};

RSPAMD_PACKED(rspamd_fuzzy_cmd)
{
	uint8_t version;
	uint8_t cmd;
	uint8_t shingles_count;
	uint8_t flag;
	int32_t value;
	uint32_t tag;
	char digest[rspamd_cryptobox_HASHBYTES];
};

RSPAMD_PACKED(rspamd_fuzzy_shingle_cmd)
{
	struct rspamd_fuzzy_cmd basic;
	struct rspamd_shingle sgl;
};

RSPAMD_PACKED(rspamd_fuzzy_reply_v1)
{
	int32_t value;
	uint32_t flag;
	uint32_t tag;
	float prob;
};

RSPAMD_PACKED(rspamd_fuzzy_reply)
{
	struct rspamd_fuzzy_reply_v1 v1;
	char digest[rspamd_cryptobox_HASHBYTES];
	uint32_t ts;
	unsigned char reserved[12];
};

RSPAMD_PACKED(rspamd_fuzzy_encrypted_req_hdr)
{
	unsigned char magic[4];
	unsigned char key_id[RSPAMD_FUZZY_KEYLEN];
	unsigned char pubkey[32];
	unsigned char nonce[rspamd_cryptobox_MAX_NONCEBYTES];
	unsigned char mac[rspamd_cryptobox_MAX_MACBYTES];
};

RSPAMD_PACKED(rspamd_fuzzy_encrypted_cmd)
{
	struct rspamd_fuzzy_encrypted_req_hdr hdr;
	struct rspamd_fuzzy_cmd cmd;
};

RSPAMD_PACKED(rspamd_fuzzy_encrypted_shingle_cmd)
{
	struct rspamd_fuzzy_encrypted_req_hdr hdr;
	struct rspamd_fuzzy_shingle_cmd cmd;
};

RSPAMD_PACKED(rspamd_fuzzy_encrypted_rep_hdr)
{
	unsigned char nonce[rspamd_cryptobox_MAX_NONCEBYTES];
	unsigned char mac[rspamd_cryptobox_MAX_MACBYTES];
};

RSPAMD_PACKED(rspamd_fuzzy_encrypted_reply)
{
	struct rspamd_fuzzy_encrypted_rep_hdr hdr;
	struct rspamd_fuzzy_reply rep;
};

#define RSPAMD_FUZZY_MAX_EXTRA_FLAGS 7

RSPAMD_PACKED(rspamd_fuzzy_flag_entry)
{
	int32_t value;
	uint32_t flag;
};

RSPAMD_PACKED(rspamd_fuzzy_reply_v2)
{
	struct rspamd_fuzzy_reply_v1 v1;
	char digest[rspamd_cryptobox_HASHBYTES];
	uint32_t ts;
	uint8_t n_extra_flags;
	uint8_t reserved[3];
	struct rspamd_fuzzy_flag_entry extra_flags[RSPAMD_FUZZY_MAX_EXTRA_FLAGS];
};

RSPAMD_PACKED(rspamd_fuzzy_encrypted_reply_v2)
{
	struct rspamd_fuzzy_encrypted_rep_hdr hdr;
	struct rspamd_fuzzy_reply_v2 rep;
};

static const unsigned char fuzzy_encrypted_magic[4] = {'r', 's', 'f', 'e'};

enum rspamd_fuzzy_extension_type {
	RSPAMD_FUZZY_EXT_SOURCE_DOMAIN = 'd',
	RSPAMD_FUZZY_EXT_SOURCE_IP4 = '4',
	RSPAMD_FUZZY_EXT_SOURCE_IP6 = '6',
};

struct rspamd_fuzzy_cmd_extension {
	enum rspamd_fuzzy_extension_type ext;
	unsigned int length;
	struct rspamd_fuzzy_cmd_extension *next;
	unsigned char *payload;
};

struct rspamd_fuzzy_stat_entry {
	const char *name;
	uint64_t fuzzy_cnt;
};

RSPAMD_PACKED(fuzzy_peer_cmd)
{
	int32_t is_shingle;
	union {
		struct rspamd_fuzzy_cmd normal;
		struct rspamd_fuzzy_shingle_cmd shingle;
	} cmd;
};

#ifdef __cplusplus
}
#endif

#endif
