reticulum 0.1.0

pub mod hdlc;

pub mod kaonic;
pub mod tcp_client;
pub mod tcp_server;
pub mod udp;

use std::sync::Arc;
use std::sync::Mutex;

use tokio::sync::mpsc;
use tokio::task;
use tokio_util::sync::CancellationToken;

use crate::hash::AddressHash;
use crate::hash::Hash;
use crate::packet::Packet;

pub type InterfaceTxSender = mpsc::Sender<TxMessage>;
pub type InterfaceTxReceiver = mpsc::Receiver<TxMessage>;

pub type InterfaceRxSender = mpsc::Sender<RxMessage>;
pub type InterfaceRxReceiver = mpsc::Receiver<RxMessage>;

#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub enum TxMessageType {
    Broadcast(Option<AddressHash>),
    Direct(AddressHash),
}

#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub struct TxMessage {
    pub tx_type: TxMessageType,
    pub packet: Packet,
}

#[derive(Debug, PartialEq, Eq, Copy, Clone)]
pub struct RxMessage {
    pub address: AddressHash, // Address of source interface
    pub packet: Packet,       // Received packet
}

pub struct InterfaceChannel {
    pub address: AddressHash,
    pub rx_channel: InterfaceRxSender,
    pub tx_channel: InterfaceTxReceiver,
    pub stop: CancellationToken,
}

impl InterfaceChannel {
    pub fn make_rx_channel(cap: usize) -> (InterfaceRxSender, InterfaceRxReceiver) {
        mpsc::channel(cap)
    }

    pub fn make_tx_channel(cap: usize) -> (InterfaceTxSender, InterfaceTxReceiver) {
        mpsc::channel(cap)
    }

    pub fn new(
        rx_channel: InterfaceRxSender,
        tx_channel: InterfaceTxReceiver,
        address: AddressHash,
        stop: CancellationToken,
    ) -> Self {
        Self {
            address,
            rx_channel,
            tx_channel,
            stop,
        }
    }

    pub fn address(&self) -> &AddressHash {
        &self.address
    }

    pub fn split(self) -> (InterfaceRxSender, InterfaceTxReceiver) {
        (self.rx_channel, self.tx_channel)
    }
}

pub trait Interface {
    fn mtu() -> usize;
}

struct LocalInterface {
    address: AddressHash,
    tx_send: InterfaceTxSender,
    stop: CancellationToken,
}

pub struct InterfaceContext<T: Interface> {
    pub inner: Arc<Mutex<T>>,
    pub channel: InterfaceChannel,
    pub cancel: CancellationToken,
}

pub struct InterfaceManager {
    counter: usize,
    rx_recv: Arc<tokio::sync::Mutex<InterfaceRxReceiver>>,
    rx_send: InterfaceRxSender,
    cancel: CancellationToken,
    ifaces: Vec<LocalInterface>,
}

impl InterfaceManager {
    pub fn new(rx_cap: usize) -> Self {
        let (rx_send, rx_recv) = InterfaceChannel::make_rx_channel(rx_cap);
        let rx_recv = Arc::new(tokio::sync::Mutex::new(rx_recv));

        Self {
            counter: 0,
            rx_recv,
            rx_send,
            cancel: CancellationToken::new(),
            ifaces: Vec::new(),
        }
    }

    pub fn new_channel(&mut self, tx_cap: usize) -> InterfaceChannel {
        self.counter += 1;

        let counter_bytes = self.counter.to_le_bytes();
        let address = AddressHash::new_from_hash(&Hash::new_from_slice(&counter_bytes[..]));

        let (tx_send, tx_recv) = InterfaceChannel::make_tx_channel(tx_cap);

        log::debug!("iface: create channel {}", address);

        let stop = CancellationToken::new();

        self.ifaces.push(LocalInterface {
            address,
            tx_send,
            stop: stop.clone(),
        });

        InterfaceChannel {
            rx_channel: self.rx_send.clone(),
            tx_channel: tx_recv,
            address,
            stop,
        }
    }

    pub fn new_context<T: Interface>(&mut self, inner: T) -> InterfaceContext<T> {
        let channel = self.new_channel(1);

        let inner = Arc::new(Mutex::new(inner));

        let context = InterfaceContext::<T> {
            inner: inner.clone(),
            channel,
            cancel: self.cancel.clone(),
        };

        context
    }

    pub fn spawn<T: Interface, F, R>(&mut self, inner: T, worker: F) -> AddressHash
    where
        F: FnOnce(InterfaceContext<T>) -> R,
        R: std::future::Future<Output = ()> + Send + 'static,
        R::Output: Send + 'static,
    {
        let context = self.new_context(inner);
        let address = context.channel.address().clone();

        task::spawn(worker(context));

        address
    }

    pub fn receiver(&self) -> Arc<tokio::sync::Mutex<InterfaceRxReceiver>> {
        self.rx_recv.clone()
    }

    pub fn cleanup(&mut self) {
        self.ifaces.retain(|iface| !iface.stop.is_cancelled());
    }

    pub async fn send(&self, message: TxMessage) {
        for iface in &self.ifaces {
            let should_send = match message.tx_type {
                TxMessageType::Broadcast(address) => {
                    let mut should_send = true;
                    if let Some(address) = address {
                        should_send = address != iface.address;
                    }

                    should_send
                },
                TxMessageType::Direct(address) => address == iface.address,
            };

            if should_send && !iface.stop.is_cancelled() {
                let _ = iface.tx_send.send(message.clone()).await;
            }
        }
    }
}

impl Drop for InterfaceManager {
    fn drop(&mut self) {
        self.cancel.cancel();
    }
}