1 files changed, 154 insertions, 0 deletions
diff --git a/p2p/src/monitor.rs b/p2p/src/monitor.rs
new file mode 100644
index 0000000..ee0bf44
--- /dev/null
+++ b/p2p/src/monitor.rs
@@ -0,0 +1,154 @@
+use std::fmt;
+
+use crate::PeerID;
+
+use karyons_core::pubsub::{ArcPublisher, Publisher, Subscription};
+
+use karyons_net::Endpoint;
+
+/// Responsible for network and system monitoring.
+///
+/// It use pub-sub pattern to notify the subscribers with new events.
+///
+/// # Example
+///
+/// ```
+/// use karyons_p2p::{Config, Backend, PeerID};
+/// async {
+///     
+///     let backend = Backend::new(PeerID::random(), Config::default());
+///     
+///     // Create a new Subscription
+///     let sub =  backend.monitor().await;
+///     
+///     let event = sub.recv().await;
+/// };
+/// ```
+pub struct Monitor {
+    inner: ArcPublisher<MonitorEvent>,
+}
+
+impl Monitor {
+    /// Creates a new Monitor
+    pub(crate) fn new() -> Monitor {
+        Self {
+            inner: Publisher::new(),
+        }
+    }
+
+    /// Sends a new monitor event to all subscribers.
+    pub async fn notify(&self, event: &MonitorEvent) {
+        self.inner.notify(event).await;
+    }
+
+    /// Subscribes to listen to new events.
+    pub async fn subscribe(&self) -> Subscription<MonitorEvent> {
+        self.inner.subscribe().await
+    }
+}
+
+/// Defines various type of event that can be monitored.
+#[derive(Clone, Debug)]
+pub enum MonitorEvent {
+    Conn(ConnEvent),
+    PeerPool(PeerPoolEvent),
+    Discovery(DiscoveryEvent),
+}
+
+/// Defines connection-related events.
+#[derive(Clone, Debug)]
+pub enum ConnEvent {
+    Connected(Endpoint),
+    ConnectRetried(Endpoint),
+    ConnectFailed(Endpoint),
+    Accepted(Endpoint),
+    AcceptFailed,
+    Disconnected(Endpoint),
+    Listening(Endpoint),
+    ListenFailed(Endpoint),
+}
+
+/// Defines `PeerPool` events.
+#[derive(Clone, Debug)]
+pub enum PeerPoolEvent {
+    NewPeer(PeerID),
+    RemovePeer(PeerID),
+}
+
+/// Defines `Discovery` events.
+#[derive(Clone, Debug)]
+pub enum DiscoveryEvent {
+    LookupStarted(Endpoint),
+    LookupFailed(Endpoint),
+    LookupSucceeded(Endpoint, usize),
+    RefreshStarted,
+}
+
+impl fmt::Display for MonitorEvent {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let val = match self {
+            MonitorEvent::Conn(e) => format!("Connection Event: {e}"),
+            MonitorEvent::PeerPool(e) => format!("PeerPool Event: {e}"),
+            MonitorEvent::Discovery(e) => format!("Discovery Event: {e}"),
+        };
+        write!(f, "{}", val)
+    }
+}
+
+impl fmt::Display for ConnEvent {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let val = match self {
+            ConnEvent::Connected(endpoint) => format!("Connected: {endpoint}"),
+            ConnEvent::ConnectFailed(endpoint) => format!("ConnectFailed: {endpoint}"),
+            ConnEvent::ConnectRetried(endpoint) => format!("ConnectRetried: {endpoint}"),
+            ConnEvent::AcceptFailed => "AcceptFailed".to_string(),
+            ConnEvent::Accepted(endpoint) => format!("Accepted: {endpoint}"),
+            ConnEvent::Disconnected(endpoint) => format!("Disconnected: {endpoint}"),
+            ConnEvent::Listening(endpoint) => format!("Listening: {endpoint}"),
+            ConnEvent::ListenFailed(endpoint) => format!("ListenFailed: {endpoint}"),
+        };
+        write!(f, "{}", val)
+    }
+}
+
+impl fmt::Display for PeerPoolEvent {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let val = match self {
+            PeerPoolEvent::NewPeer(pid) => format!("NewPeer: {pid}"),
+            PeerPoolEvent::RemovePeer(pid) => format!("RemovePeer: {pid}"),
+        };
+        write!(f, "{}", val)
+    }
+}
+
+impl fmt::Display for DiscoveryEvent {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let val = match self {
+            DiscoveryEvent::LookupStarted(endpoint) => format!("LookupStarted: {endpoint}"),
+            DiscoveryEvent::LookupFailed(endpoint) => format!("LookupFailed: {endpoint}"),
+            DiscoveryEvent::LookupSucceeded(endpoint, len) => {
+                format!("LookupSucceeded: {endpoint} {len}")
+            }
+            DiscoveryEvent::RefreshStarted => "RefreshStarted".to_string(),
+        };
+        write!(f, "{}", val)
+    }
+}
+
+impl From<ConnEvent> for MonitorEvent {
+    fn from(val: ConnEvent) -> Self {
+        MonitorEvent::Conn(val)
+    }
+}
+
+impl From<PeerPoolEvent> for MonitorEvent {
+    fn from(val: PeerPoolEvent) -> Self {
+        MonitorEvent::PeerPool(val)
+    }
+}
+
+impl From<DiscoveryEvent> for MonitorEvent {
+    fn from(val: DiscoveryEvent) -> Self {
+        MonitorEvent::Discovery(val)
+    }
+}