avr/packet-radio/src/radio.c

/*
Copyright 2022, Savanni D'Gerinel <savanni@luminescent-dreams.com>

This file is part of Savanni's AVR library.

This AVR library is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This AVR library 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 General Public License for more details.

You should have received a copy of the GNU General Public License along with this AVR library. If not, see <https://www.gnu.org/licenses/>.
*/

#include "radio.h"
#include "packet.h"
#include "packet_buffer.h"
#include <string.h>

struct conn_s {
    uint16_t packet_counter;
    uint8_t address;

    packet_buffer_t outgoing;
    packet_buffer_t incoming;

    void (*set_mode)(radio_t *, radio_mode_e, radio_status_e *);
    flags_t (*get_flags)(radio_t *, radio_status_e *);
    void (*transmit)(radio_t *, packet_t *, radio_status_e *);
    void (*receive)(radio_t *, uint8_t data[66], radio_status_e *);

    radio_t *radio;
};

conn_t * conn_connect(radio_t *radio) {
    conn_t *connection = malloc(sizeof(struct conn_s));
    connection->packet_counter = 0;
    connection->address = 0;

    packet_buffer_init(&connection->outgoing);
    packet_buffer_init(&connection->incoming);

    connection->set_mode = radio->set_mode;
    connection->get_flags = radio->get_flags;
    connection->transmit = radio->transmit;
    connection->receive = radio->receive;
    connection->radio = radio;

    return connection;
}

void conn_set_address(conn_t *self, uint8_t addr, radio_status_e *status) {
    if (!IS_OK(status)) return;
    self->address = addr;
}

void conn_set_mode(conn_t *self, radio_mode_e mode, radio_status_e *status) {
    if (!IS_OK(status)) return;
    self->set_mode(self->radio, mode, status);
}

flags_t conn_get_flags(conn_t *self, radio_status_e *status) {
    if (!IS_OK(status)) return (flags_t){ .packet_sent = false, .packet_ready = false };
    return self->get_flags(self->radio, status);
}

void conn_send(conn_t *self, uint8_t dest, msg_t *message, radio_status_e *status) {
    if (!IS_OK(status)) return;

    if (message->length > MAX_MESSAGE_LENGTH) {
        *status = message_too_long;
        return;
    }

    if (packet_buffer_is_full(&self->outgoing)) {
        *status = outgoing_full;
        return;
    }

    packet_buffer_status_e buffer_status = packet_buffer_status_ok;

    packet_t *packet = packet_buffer_enqueue(&self->outgoing, &buffer_status);
    if (!IS_OK(&buffer_status)) {
        switch (buffer_status) {
            case packet_buffer_status_full:
                *status = outgoing_full;
                break;
            default:
                *status = unhandled_error;
                break;
        }
        return;
    }

    packet->type = packet_type_data;
    packet->count = self->packet_counter;
    packet->sender = self->address;
    packet->receiver = dest;
    packet->length = message->length;
    memcpy(&packet->message, message->data, message->length);

    self->transmit(self->radio, packet, status);
    if (!IS_OK(status)) return;

    return;
}

received_msg_t * conn_receive(conn_t *self, radio_status_e *status) {
    if (!IS_OK(status)) return NULL;

    if (packet_buffer_is_empty(&self->incoming)) {
        *status = packet_buffer_status_empty;
        return NULL;
    }

    packet_buffer_status_e buffer_status = packet_buffer_status_ok;
    packet_t *packet = packet_buffer_head(&self->incoming, &buffer_status);
    if (!IS_OK(&buffer_status)) {
        // *status =
    }

    received_msg_t *msg = malloc(sizeof(received_msg_t) + packet->length);
    msg->sender = packet->sender;
    msg->message.length = packet->length;
    memcpy(msg->message.data, packet->message, packet->length);

    packet_buffer_dequeue(&self->incoming, &buffer_status);
    if (!IS_OK(&buffer_status)) {
    }

    return msg;
}

void conn_handle_interrupt(conn_t *self) {
    /*
    radio_status_e *status = ok;

    flags_t flags = self->get_flags(self->radio, status);
    // if this is failing, we should raise a flag that indicates that the radio itself is in trouble
    if (!IS_OK(status)) return;

    if (flags.packet_ready) {
        uint8_t data[66];
        self->receive(self->radio, data, status);
        // if this fails, increment an error counter
        if (!IS_OK(status)) return;

        packet_t *packet = (packet_t *)data;
        if (packet->receiver != self->address) {
            return;
        }

        switch (packet->type) {
            case packet_type_data:
                packet_buffer_status_e status;
                packet_t *dest = packet_buffer_enqueue(self->incoming, &status);
                memcpy(dest, packet, sizeof(packet_t) + packet->length);
                break;
            case packet_type_ack:
                // uint16_t confirmed = packet->data[0] << 8 + packet->data[1];
                // while (self->outgoing_buffer[self->outgoing_bottom]->count < confirmed && !is_empty(self->outgoing_buffer)
                break;
            case packet_type_retry:
                break;
        }
        // process the packet type
        // break;
    }

    // timeout processing
    // if (time > receiving_timeout) { }
    // if we were receiving data, a receiving_timeout must have been set. At this point, we're not receiving any more data, so it's time to send a confirmation.
    // if (time > confirmation_timeout) { }
    // if we were sending data, a confirmation timeout must have been set. But I don't recall what this is good for? Do we want to retransmit everything?
    */
}