/*
 * SPDX-License-Identifier: AGPL-3.0-only
 * Copyright (c) Camden Dixie O'Brien
 */

#ifndef PROTOCOL_INTERFACE_H
#define PROTOCOL_INTERFACE_H

#include "protocol_messages.h"

typedef ResponseStatus (*CommandHandler)(
    const Message *command, Message *response_out);

/**
 * Initialize the protocol interface and start listening for commands.
 */
void protocol_interface_init(void);

/**
 * Set the handler for commands with a given intruction.
 *
 * The handler will be invoked when/if a command with the specified
 * instruction is received. The response status should be returned,
 * and upon success the response should be populated. Strings in the
 * response must be allocated with alloc_message_string(); these will
 * be freed by the interface when the response has been sent.
 *
 * Only a single handler can be set for a given instruction; if
 * multiple are added then only the one added last will be used.
 */
void set_command_handler(
    CommandInstruction instruction, CommandHandler handler);

/**
 * Allocate a buffer for a string with the given length (in bytes),
 * returning a pointer to it or NULL if space has ran out.
 *
 * The actual space allocated will be length + 1 bytes, and the last
 * byte in this buffer will be set to the null character.
 */
char *alloc_message_string(unsigned length);

#endif