/*
Copyright (c) 2010-2020 Roger Light <roger@atchoo.org>

All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
and Eclipse Distribution License v1.0 which accompany this distribution.
 
The Eclipse Public License is available at
   https://www.eclipse.org/legal/epl-2.0/
and the Eclipse Distribution License is available at
  http://www.eclipse.org/org/documents/edl-v10.php.
 
SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause

Contributors:
   Roger Light - initial implementation and documentation.
*/

#ifndef PERSIST_H
#define PERSIST_H

#define MOSQ_DB_VERSION 6

/* DB read/write */
extern const unsigned char magic[15];
#define DB_CHUNK_CFG 1
#define DB_CHUNK_MSG_STORE 2
#define DB_CHUNK_CLIENT_MSG 3
#define DB_CHUNK_RETAIN 4
#define DB_CHUNK_SUB 5
#define DB_CHUNK_CLIENT 6
/* End DB read/write */

#define read_e(f, b, c) if(fread(b, 1, c, f) != c){ goto error; }
#define write_e(f, b, c) if(fwrite(b, 1, c, f) != c){ goto error; }

/* COMPATIBILITY NOTES
 *
 * The P_* structs (persist structs) contain all of the data for a particular
 * data chunk. They are loaded in multiple parts, so can be rearranged without
 * updating the db format version.
 *
 * The PF_* structs (persist fixed structs) contain the fixed size data for a
 * particular data chunk. They are written to disk as is, so they must not be
 * rearranged without updating the db format version. When adding new members,
 * always use explicit sized datatypes ("uint32_t", not "long"), and check
 * whether what is being added can go in an existing hole in the struct.
 */

struct PF_header{
	uint32_t chunk;
	uint32_t length;
};


struct PF_cfg{
	uint64_t last_db_id;
	uint8_t shutdown;
	uint8_t dbid_size;
};

struct PF_client_v5{
	int64_t session_expiry_time;
	uint32_t session_expiry_interval;
	uint16_t last_mid;
	uint16_t id_len;
};
struct PF_client{
	/* struct PF_client_v5; */
	int64_t session_expiry_time;
	uint32_t session_expiry_interval;
	uint16_t last_mid;
	uint16_t id_len;

	uint16_t listener_port;
	uint16_t username_len;
	/* tail: 4 byte padding, because 64bit member 
	 * forces multiple of 8 for struct size */
};
struct P_client{
	struct PF_client F;
	char *client_id;
	char *username;
};


struct PF_client_msg{
	dbid_t store_id;
	uint16_t mid;
	uint16_t id_len;
	uint8_t qos;
	uint8_t state;
	uint8_t retain_dup;
	uint8_t direction;
};
struct P_client_msg{
	struct PF_client_msg F;
	char *client_id;
	mosquitto_property *properties;
};


struct PF_msg_store{
	dbid_t store_id;
	int64_t expiry_time;
	uint32_t payloadlen;
	uint16_t source_mid;
	uint16_t source_id_len;
	uint16_t source_username_len;
	uint16_t topic_len;
	uint16_t source_port;
	uint8_t qos;
	uint8_t retain;
};
struct P_msg_store{
	struct PF_msg_store F;
	void *payload;
	struct mosquitto source;
	char *topic;
	mosquitto_property *properties;
};


struct PF_sub{
	uint32_t identifier;
	uint16_t id_len;
	uint16_t topic_len;
	uint8_t qos;
	uint8_t options;
};
struct P_sub{
	struct PF_sub F;
	char *client_id;
	char *topic;
};


struct PF_retain{
	dbid_t store_id;
};
struct P_retain{
	struct PF_retain F;
};


int persist__read_string_len(FILE *db_fptr, char **str, uint16_t len);
int persist__read_string(FILE *db_fptr, char **str);

int persist__chunk_header_read(FILE *db_fptr, uint32_t *chunk, uint32_t *length);

int persist__chunk_header_read_v234(FILE *db_fptr, uint32_t *chunk, uint32_t *length);
int persist__chunk_cfg_read_v234(FILE *db_fptr, struct PF_cfg *chunk);
int persist__chunk_client_read_v234(FILE *db_fptr, struct P_client *chunk, uint32_t db_version);
int persist__chunk_client_msg_read_v234(FILE *db_fptr, struct P_client_msg *chunk);
int persist__chunk_msg_store_read_v234(FILE *db_fptr, struct P_msg_store *chunk, uint32_t db_version);
int persist__chunk_retain_read_v234(FILE *db_fptr, struct P_retain *chunk);
int persist__chunk_sub_read_v234(FILE *db_fptr, struct P_sub *chunk);

int persist__chunk_header_read_v56(FILE *db_fptr, uint32_t *chunk, uint32_t *length);
int persist__chunk_cfg_read_v56(FILE *db_fptr, struct PF_cfg *chunk);
int persist__chunk_client_read_v56(FILE *db_fptr, struct P_client *chunk, uint32_t db_version);
int persist__chunk_client_msg_read_v56(FILE *db_fptr, struct P_client_msg *chunk, uint32_t length);
int persist__chunk_msg_store_read_v56(FILE *db_fptr, struct P_msg_store *chunk, uint32_t length);
int persist__chunk_retain_read_v56(FILE *db_fptr, struct P_retain *chunk);
int persist__chunk_sub_read_v56(FILE *db_fptr, struct P_sub *chunk);

int persist__chunk_cfg_write_v6(FILE *db_fptr, struct PF_cfg *chunk);
int persist__chunk_client_write_v6(FILE *db_fptr, struct P_client *chunk);
int persist__chunk_client_msg_write_v6(FILE *db_fptr, struct P_client_msg *chunk);
int persist__chunk_message_store_write_v6(FILE *db_fptr, struct P_msg_store *chunk);
int persist__chunk_retain_write_v6(FILE *db_fptr, struct P_retain *chunk);
int persist__chunk_sub_write_v6(FILE *db_fptr, struct P_sub *chunk);

#endif
