1 files changed, 139 insertions, 0 deletions
diff --git a/p2p/src/backend.rs b/p2p/src/backend.rs
new file mode 100644
index 0000000..290e3e7
--- /dev/null
+++ b/p2p/src/backend.rs
@@ -0,0 +1,139 @@
+use std::sync::Arc;
+
+use log::info;
+
+use karyons_core::{pubsub::Subscription, Executor};
+
+use crate::{
+    config::Config,
+    discovery::{ArcDiscovery, Discovery},
+    monitor::{Monitor, MonitorEvent},
+    net::ConnQueue,
+    peer_pool::PeerPool,
+    protocol::{ArcProtocol, Protocol},
+    ArcPeer, PeerID, Result,
+};
+
+pub type ArcBackend = Arc<Backend>;
+
+/// Backend serves as the central entry point for initiating and managing
+/// the P2P network.
+///
+///
+/// # Example
+/// ```
+/// use std::sync::Arc;
+///
+/// use easy_parallel::Parallel;
+/// use smol::{channel as smol_channel, future, Executor};
+///
+/// use karyons_p2p::{Backend, Config, PeerID};
+///
+/// let peer_id = PeerID::random();
+///
+/// // Create the configuration for the backend.
+/// let mut config = Config::default();
+///
+/// // Create a new Backend
+/// let backend = Backend::new(peer_id, config);
+///
+/// // Create a new Executor
+/// let ex = Arc::new(Executor::new());
+///
+/// let task = async {
+///     // Run the backend
+///     backend.run(ex.clone()).await.unwrap();
+///
+///     // ....
+///
+///     // Shutdown the backend
+///     backend.shutdown().await;
+/// };
+///
+/// future::block_on(ex.run(task));
+///
+/// ```
+pub struct Backend {
+    /// The Configuration for the P2P network.
+    config: Arc<Config>,
+
+    /// Peer ID.
+    id: PeerID,
+
+    /// Responsible for network and system monitoring.
+    monitor: Arc<Monitor>,
+
+    /// Discovery instance.
+    discovery: ArcDiscovery,
+
+    /// PeerPool instance.
+    peer_pool: Arc<PeerPool>,
+}
+
+impl Backend {
+    /// Creates a new Backend.
+    pub fn new(id: PeerID, config: Config) -> ArcBackend {
+        let config = Arc::new(config);
+        let monitor = Arc::new(Monitor::new());
+
+        let conn_queue = ConnQueue::new();
+
+        let peer_pool = PeerPool::new(&id, conn_queue.clone(), config.clone(), monitor.clone());
+        let discovery = Discovery::new(&id, conn_queue, config.clone(), monitor.clone());
+
+        Arc::new(Self {
+            id: id.clone(),
+            monitor,
+            discovery,
+            config,
+            peer_pool,
+        })
+    }
+
+    /// Run the Backend, starting the PeerPool and Discovery instances.
+    pub async fn run(self: &Arc<Self>, ex: Executor<'_>) -> Result<()> {
+        info!("Run the backend {}", self.id);
+        self.peer_pool.start(ex.clone()).await?;
+        self.discovery.start(ex.clone()).await?;
+        Ok(())
+    }
+
+    /// Attach a custom protocol to the network
+    pub async fn attach_protocol<P: Protocol>(
+        &self,
+        c: impl Fn(ArcPeer) -> ArcProtocol + Send + Sync + 'static,
+    ) -> Result<()> {
+        self.peer_pool.attach_protocol::<P>(Box::new(c)).await
+    }
+
+    /// Returns the number of currently connected peers.
+    pub async fn peers(&self) -> usize {
+        self.peer_pool.peers_len().await
+    }
+
+    /// Returns the `Config`.
+    pub fn config(&self) -> Arc<Config> {
+        self.config.clone()
+    }
+
+    /// Returns the number of occupied inbound slots.
+    pub fn inbound_slots(&self) -> usize {
+        self.discovery.inbound_slots.load()
+    }
+
+    /// Returns the number of occupied outbound slots.
+    pub fn outbound_slots(&self) -> usize {
+        self.discovery.outbound_slots.load()
+    }
+
+    /// Subscribes to the monitor to receive network events.
+    pub async fn monitor(&self) -> Subscription<MonitorEvent> {
+        self.monitor.subscribe().await
+    }
+
+    /// Shuts down the Backend.
+    pub async fn shutdown(&self) {
+        self.discovery.shutdown().await;
+        self.peer_pool.shutdown().await;
+    }
+}