monocoque/zmq/

subscriber.rs

//! SUB socket implementation.

use bytes::Bytes;
use monocoque_core::monitor::{SocketEvent, SocketEventSender, SocketMonitor, create_monitor};
use monocoque_core::options::SocketOptions;
use monocoque_core::rt::TcpStream;
use monocoque_zmtp::SocketType;
use monocoque_zmtp::subscriber::SubSocket as InternalSub;
use std::io;

/// A SUB socket for receiving filtered messages.
///
/// SUB sockets connect to PUB peers and filter messages by topic prefix.
/// They're used for:
///
/// - Event subscriptions
/// - Topic-based message filtering
/// - Many-to-one aggregation
///
/// ## ZeroMQ Compatibility
///
/// Compatible with `zmq::SUB` and `zmq::PUB` sockets from libzmq.
///
/// ## Example
///
/// ```rust,no_run
/// use monocoque::zmq::SubSocket;
///
/// # async fn example() -> Result<(), Box<dyn std::error::Error>> {
/// let mut socket = SubSocket::connect("127.0.0.1:5555").await?;
///
/// // Subscribe to topic
/// socket.subscribe(b"topic");
///
/// // Receive filtered messages
/// loop {
///     match socket.recv().await? {
///         Some(msg) => println!("Received: {:?}", msg),
///         None => break, // Connection closed
///     }
/// }
/// # Ok(())
/// # }
/// ```
pub struct SubSocket<S = TcpStream>
where
    S: compio_io::AsyncRead + compio_io::AsyncWrite + Unpin,
{
    inner: InternalSub<S>,
    monitor: Option<SocketEventSender>,
}

impl SubSocket {
    /// Connect to a PUB peer and create a SUB socket.
    ///
    /// Accepts TCP endpoints or raw socket addresses:
    /// - `"tcp://127.0.0.1:5555"`
    /// - `"127.0.0.1:5555"`
    ///
    /// For IPC (Unix domain sockets), use [`SubSocket::connect_ipc()`].
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use monocoque::zmq::SubSocket;
    ///
    /// # async fn example() -> Result<(), Box<dyn std::error::Error>> {
    /// let mut socket = SubSocket::connect("127.0.0.1:5555").await?;
    /// socket.subscribe(b""); // Subscribe to all messages
    /// # Ok(())
    /// # }
    /// ```
    pub async fn connect(endpoint: &str) -> io::Result<Self> {
        // Try parsing as endpoint, fall back to raw address
        let addr = if let Ok(monocoque_core::endpoint::Endpoint::Tcp(a)) =
            monocoque_core::endpoint::Endpoint::parse(endpoint)
        {
            a
        } else {
            endpoint
                .parse::<std::net::SocketAddr>()
                .map_err(|e| io::Error::new(io::ErrorKind::InvalidInput, e))?
        };

        let sock = Self {
            inner: InternalSub::connect(addr).await?,
            monitor: None,
        };
        sock.emit_event(SocketEvent::Connected(
            monocoque_core::endpoint::Endpoint::Tcp(addr),
        ));
        Ok(sock)
    }

    /// Connect to a publisher with custom socket options.
    ///
    /// Counterpart to [`connect`](Self::connect) for callers that need to set
    /// buffer sizes, timeouts, or subscriptions before the connection is made.
    ///
    /// # Errors
    ///
    /// Returns an error if the address cannot be parsed or the connection and
    /// ZMTP handshake fail.
    pub async fn connect_with_options(
        addr: impl monocoque_core::rt::ToSocketAddrs,
        options: monocoque_core::options::SocketOptions,
    ) -> io::Result<Self> {
        Ok(Self {
            inner: InternalSub::connect_with_options(addr, options).await?,
            monitor: None,
        })
    }

    /// Check if the socket is currently connected.
    #[inline]
    pub fn is_connected(&self) -> bool {
        self.inner.is_connected()
    }

    /// Try to reconnect to the stored endpoint, re-sending all active subscriptions.
    pub async fn try_reconnect(&mut self) -> io::Result<()> {
        self.inner.try_reconnect().await
    }

    /// Receive with automatic reconnection on EOF or network error.
    pub async fn recv_with_reconnect(&mut self) -> io::Result<Option<Vec<bytes::Bytes>>> {
        self.inner.recv_with_reconnect().await
    }

    /// Connect to a PUB peer via IPC (Unix domain sockets).
    ///
    /// Unix-only. Accepts IPC paths with or without `ipc://` prefix:
    /// - `"ipc:///tmp/socket.sock"`
    /// - `"/tmp/socket.sock"`
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// # #[cfg(unix)]
    /// # async fn example() -> Result<(), Box<dyn std::error::Error>> {
    /// use monocoque::zmq::SubSocket;
    ///
    /// let mut socket = SubSocket::connect_ipc("/tmp/pubsub.sock").await?;
    /// socket.subscribe(b"");
    /// # Ok(())
    /// # }
    /// ```
    #[cfg(unix)]
    pub async fn connect_ipc(path: &str) -> io::Result<SubSocket<monocoque_core::rt::UnixStream>> {
        use std::path::PathBuf;

        // Strip "ipc://" prefix if present
        let clean_path = path.strip_prefix("ipc://").unwrap_or(path);
        let ipc_path = PathBuf::from(clean_path);

        let stream = monocoque_core::ipc::connect(&ipc_path).await?;
        let sock = SubSocket::from_unix_stream(stream).await?;
        sock.emit_event(SocketEvent::Connected(
            monocoque_core::endpoint::Endpoint::Ipc(ipc_path),
        ));
        Ok(sock)
    }

    /// Create a SUB socket from a TCP stream with TCP_NODELAY enabled.
    pub async fn from_tcp(stream: TcpStream) -> io::Result<Self> {
        Ok(Self {
            inner: InternalSub::from_tcp(stream).await?,
            monitor: None,
        })
    }

    /// Create a SUB socket from a TCP stream with custom options.
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use monocoque::zmq::{SubSocket, SocketOptions};
    /// use monocoque_core::rt::TcpStream;
    ///
    /// # async fn example() -> Result<(), Box<dyn std::error::Error>> {
    /// let stream = TcpStream::connect("127.0.0.1:5555").await?;
    /// let socket = SubSocket::from_tcp_with_options(
    ///     stream,
    ///     SocketOptions::default()
    ///         .with_recv_hwm(500)
    ///         .with_buffer_sizes(4096, 4096)
    /// ).await?;
    /// # Ok(())
    /// # }
    /// ```
    pub async fn from_tcp_with_options(
        stream: TcpStream,
        options: monocoque_core::options::SocketOptions,
    ) -> io::Result<Self> {
        Ok(Self {
            inner: InternalSub::from_tcp_with_options(stream, options).await?,
            monitor: None,
        })
    }

    /// Create a SUB socket from any stream with custom options.
    pub async fn with_options<Stream>(
        stream: Stream,
        options: monocoque_core::options::SocketOptions,
    ) -> io::Result<SubSocket<Stream>>
    where
        Stream: compio_io::AsyncRead + compio_io::AsyncWrite + Unpin,
    {
        Ok(SubSocket {
            inner: InternalSub::with_options(stream, options).await?,
            monitor: None,
        })
    }
}

// Generic impl - works with any stream type
impl<S> SubSocket<S>
where
    S: compio_io::AsyncRead + compio_io::AsyncWrite + Unpin,
{
    /// Enable monitoring for this socket.
    ///
    /// Returns a receiver for socket lifecycle events.
    pub fn monitor(&mut self) -> SocketMonitor {
        let (sender, receiver) = create_monitor();
        self.monitor = Some(sender);
        receiver
    }

    /// Helper to emit monitoring events (if monitoring is enabled).
    fn emit_event(&self, event: SocketEvent) {
        if let Some(monitor) = &self.monitor {
            monocoque_core::monitor::emit(monitor, event);
        }
    }

    /// Subscribe to messages matching the given topic prefix.
    ///
    /// Empty topic subscribes to all messages.
    ///
    /// This sends a subscription message to the PUB socket.
    pub async fn subscribe(&mut self, topic: &[u8]) -> io::Result<()> {
        self.inner.subscribe(Bytes::copy_from_slice(topic)).await
    }

    /// Unsubscribe from messages matching the given topic prefix.
    ///
    /// This sends an unsubscription message to the PUB socket.
    pub async fn unsubscribe(&mut self, topic: &[u8]) -> io::Result<()> {
        self.inner.unsubscribe(&Bytes::copy_from_slice(topic)).await
    }

    /// Receive a multipart message.
    ///
    /// Only messages matching subscribed topics will be received.
    /// Returns `None` if the connection is closed.
    pub async fn recv(&mut self) -> io::Result<Option<Vec<Bytes>>> {
        self.inner.recv().await
    }

    /// Receive a matching message into a caller-provided buffer, reusing its
    /// allocation. Allocation-free counterpart to [`recv`](Self::recv): filtered
    /// messages are dropped without allocating. Returns `Ok(true)` on a matching
    /// message, `Ok(false)` on EOF.
    pub async fn recv_into(&mut self, out: &mut Vec<Bytes>) -> io::Result<bool> {
        self.inner.recv_into(out).await
    }

    /// Try to receive a matching message into `out` without a kernel read.
    pub fn try_recv_into(&mut self, out: &mut Vec<Bytes>) -> io::Result<bool> {
        self.inner.try_recv_into(out)
    }

    /// Get the socket type.
    ///
    /// # ZeroMQ Compatibility
    ///
    /// Corresponds to `ZMQ_TYPE` (16) option.
    #[inline]
    pub const fn socket_type() -> SocketType {
        SocketType::Sub
    }

    /// Get the endpoint this socket is connected/bound to, if available.
    ///
    /// Returns `None` if the socket was created from a raw stream.
    ///
    /// # ZeroMQ Compatibility
    ///
    /// Corresponds to `ZMQ_LAST_ENDPOINT` (32) option.
    #[inline]
    pub fn last_endpoint(&self) -> Option<&monocoque_core::endpoint::Endpoint> {
        self.inner.last_endpoint()
    }

    /// Check if the last received message has more frames coming.
    ///
    /// Returns `true` if there are more frames in the current multipart message.
    ///
    /// # ZeroMQ Compatibility
    ///
    /// Corresponds to `ZMQ_RCVMORE` (13) option.
    #[inline]
    pub fn has_more(&self) -> bool {
        self.inner.has_more()
    }

    /// Get the event state of the socket.
    ///
    /// Returns a bitmask indicating ready-to-receive and ready-to-send states.
    ///
    /// # Returns
    ///
    /// - `1` (POLLIN) - Socket is ready to receive
    /// - `2` (POLLOUT) - Socket is ready to send
    /// - `3` (POLLIN | POLLOUT) - Socket is ready for both
    ///
    /// # ZeroMQ Compatibility
    ///
    /// Corresponds to `ZMQ_EVENTS` (15) option.
    #[inline]
    pub fn events(&self) -> u32 {
        self.inner.events()
    }

    /// Get a mutable reference to this socket's options.
    #[inline]
    pub fn options_mut(&mut self) -> &mut SocketOptions {
        self.inner.options_mut()
    }
}

// Unix-specific impl for IPC support
#[cfg(unix)]
impl SubSocket<monocoque_core::rt::UnixStream> {
    /// Create a SUB socket from an existing Unix domain socket stream (IPC).
    pub async fn from_unix_stream(stream: monocoque_core::rt::UnixStream) -> io::Result<Self> {
        Ok(Self {
            inner: InternalSub::new(stream).await?,
            monitor: None,
        })
    }

    /// Create a SUB socket from an existing Unix stream with custom options.
    ///
    /// This method provides full control over socket behavior through SocketOptions.
    pub async fn from_unix_stream_with_options(
        stream: monocoque_core::rt::UnixStream,
        options: monocoque_core::options::SocketOptions,
    ) -> io::Result<Self> {
        Ok(Self {
            inner: InternalSub::with_options(stream, options).await?,
            monitor: None,
        })
    }
}