Add SMTP server scaffolding

Signed-off-by: Mroik <mroik@delayed.space>

2 files changed, 72 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
index 60b75af..075dc7d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
 mod database;
 mod list;
+mod smtp;
 
 fn main() {
     println!("Hello, world!");
diff --git a/src/smtp.rs b/src/smtp.rs
new file mode 100644
index 0000000..affac8b
--- /dev/null
+++ b/src/smtp.rs
@@ -0,0 +1,71 @@
+use std::{
+    io::{BufRead, BufReader},
+    net::{IpAddr, SocketAddr, TcpListener, TcpStream},
+};
+
+use anyhow::Result;
+use tokio::spawn;
+
+pub struct SmtpServer {
+    listener: TcpListener,
+    running: bool,
+}
+
+impl SmtpServer {
+    pub fn new(ip: [u8; 4], port: u16) -> Result<Self> {
+        Ok(Self {
+            listener: TcpListener::bind((IpAddr::from(ip), port))?,
+            running: false,
+        })
+    }
+
+    // TODO: trap SIGINT to stop server?
+    pub async fn run(&mut self) -> Result<()> {
+        self.running = true;
+        while self.running {
+            let (stream, addr) = self.listener.accept()?;
+            let session = SessionHandler {
+                stream,
+                addr,
+                state: SessionState::default(),
+            };
+            spawn(session.run());
+        }
+        Ok(())
+    }
+}
+
+struct SessionHandler {
+    stream: TcpStream,
+    addr: SocketAddr,
+    state: SessionState,
+}
+
+impl SessionHandler {
+    async fn run(mut self) -> Result<()> {
+        let mut r = BufReader::new(&self.stream);
+        let mut buffer = String::new();
+
+        loop {
+            if r.read_line(&mut buffer)? == 0 {
+                break;
+            }
+
+            log::debug!("Received '{}' from '{}'", buffer.trim(), self.addr);
+            self.state.apply().await;
+            buffer.clear();
+        }
+
+        log::info!("Connection closed by {}", self.addr);
+        Ok(())
+    }
+}
+
+#[derive(Default)]
+struct SessionState {}
+
+impl SessionState {
+    async fn apply(&mut self) {
+        todo!()
+    }
+}