/*
 * Usurpataion --- server-client protocol private interface.
 *
 * Copyright (C) 2019 Ramūnas Mažeikis
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; version 2.1
 * of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#ifndef PROTOCOL_H_PRIVATE
#define PROTOCOL_H_PRIVATE

#include "utils.h"

#define TLV_BUF_SIZE	(16)

/* Pease don't rape the buffer with long messages, daemon-kun. */
#define MSG_BUF_SIZE	(257)

/* UDP can carry bigger packets but memory is hard to come by and more won't be
 * needed anyway.
 * */
#define PACKET_MAX_SIZE	(512)

/* Returns the amount of tlv's int a packet.
 *
 * If a tlv reports length that goes beyond the end of a packet, errno is set
 * to TLV_OVERFLOW. To check this, set errno to 0 first.
 * */
size_t tlv_count(const struct packet_data * const packet);


/**
 * Parses tlv's from packet data and writes them to a buffer of given size.
 * 
 * Returns how many tlv's were actually parsed.
 *
 * To check for errors, set errno to 0 and check after calling.
 *  
 * Not yet implemented.
 * 
 * @param data Data from network packet
 * @param buf Buffer to store parsed tlv's
 * @param buf_size Size of buffer used to store tlv's
 * 
 * @return Number of tlv's actually parsed. Greter than or equal to buffer
 * size, if an error occurs.
 * */
size_t get_tlvs(	const struct packet_data * const data,
			const struct tlv *buf,
			size_t buf_size);

/* Takes a null-terminated string and appends it to the next outgoing packet.
 * */
void push_string(char *str);

/* Reinterprets char * as fpi1_t * and appends it to the outgoing packet as a
 * tlv.
 */
void push_fpi1(char *num);

/* Reinterprets char * as time_t * and appends it to the outgoing packet as a
 * tlv.
 */
void push_timestamp(char *data);

/* Not implemented yet. */
void push_request(char *data);

/* Not implemented yet. */
void push_reply(char *data);

/* Reinterprets char * as uuid_t * and appends it to the outgoing packet as a
 * tlv.
 */
void push_uuid(char *data);

/* Appends tlv_type and size of data to a packet effectively creating a tlv
 * header.
 */
void push_tlv_header(enum tlv_type type, size_t size);

#endif /* PROTOCOL_H_PRIVATE */