keep existing session

src/lib.rs

@@ -1,7 +1,7 @@
 use std::io::{Error, Stdout};
 use std::net::TcpStream;
 use std::time::{Duration, Instant};
-use crossterm::{event};
+use crossterm::event;
 use crossterm::event::{Event, KeyCode};
 use ratatui::backend::CrosstermBackend;
 use ratatui::layout::{Constraint, Direction, Layout};
@@ -14,20 +14,86 @@ pub mod config;
 
 const POLL_INTERVAL: Duration = Duration::from_secs(30);
 
-pub(crate) struct Email {
+struct Email {
     subject: String,
     from: String,
     date: String,
 }
 
-pub fn main(config: &Config, mut terminal: &mut Terminal<CrosstermBackend<Stdout>>) -> Result<(), Error>{
+type ImapSession = imap::Session<TcpStream>;
-    let mut inbox = fetch_inbox(config);
+
+fn connect(config: &Config) -> Result<ImapSession, String> {
+    let imap_cfg = &config.imap;
+    let stream =
+        TcpStream::connect((&*imap_cfg.host, imap_cfg.port)).map_err(|e| e.to_string())?;
+    let client = imap::Client::new(stream);
+    let session = client
+        .login(&imap_cfg.username, &imap_cfg.password)
+        .map_err(|(e, _)| e.to_string())?;
+    Ok(session)
+}
+
+fn fetch_inbox(session: &mut ImapSession) -> Result<Vec<Email>, String> {
+    session.select("INBOX").map_err(|e| e.to_string())?;
+
+    let messages = session
+        .fetch("1:*", "BODY.PEEK[HEADER.FIELDS (SUBJECT FROM DATE)]")
+        .map_err(|e| e.to_string())?;
+
+    let mut emails = Vec::new();
+    for message in messages.iter() {
+        if let Some(body) = message.header() {
+            let header = String::from_utf8_lossy(body);
+            let mut subject = String::new();
+            let mut from = String::new();
+            let mut date = String::new();
+
+            for line in header.lines() {
+                if let Some(val) = line.strip_prefix("Subject: ") {
+                    subject = val.to_string();
+                } else if let Some(val) = line.strip_prefix("From: ") {
+                    from = val.to_string();
+                } else if let Some(val) = line.strip_prefix("Date: ") {
+                    date = val.to_string();
+                }
+            }
+
+            emails.push(Email { subject, from, date });
+        }
+    }
+
+    Ok(emails)
+}
+
+/// Refresh inbox using NOOP + fetch. Reconnects on error.
+fn refresh_inbox(
+    session: &mut Option<ImapSession>,
+    config: &Config,
+) -> Result<Vec<Email>, String> {
+    // If we have a session, try NOOP to keep alive / detect changes
+    if let Some(s) = session.as_mut() {
+        if s.noop().is_ok() {
+            return fetch_inbox(s);
+        }
+    }
+
+    // Session is dead or missing — reconnect
+    *session = None;
+    let mut new_session = connect(config)?;
+    let result = fetch_inbox(&mut new_session);
+    *session = Some(new_session);
+    result
+}
+
+pub fn main(config: &Config, terminal: &mut Terminal<CrosstermBackend<Stdout>>) -> Result<(), Error> {
+    let mut session = connect(config).ok();
+    let mut inbox = refresh_inbox(&mut session, config);
     let mut last_fetch = Instant::now();
 
     // --- Main loop ---
     loop {
         if last_fetch.elapsed() >= POLL_INTERVAL {
-            inbox = fetch_inbox(&config);
+            inbox = refresh_inbox(&mut session, config);
             last_fetch = Instant::now();
         }
 
@@ -83,7 +149,7 @@ pub fn main(config: &Config, mut terminal: &mut Terminal<CrosstermBackend<Stdout
                 match key.code {
                     KeyCode::Char('q') | KeyCode::Esc => break,
                     KeyCode::Char('r') => {
-                        inbox = fetch_inbox(&config);
+                        inbox = refresh_inbox(&mut session, config);
                         last_fetch = Instant::now();
                     }
                     _ => {}
@@ -92,51 +158,10 @@ pub fn main(config: &Config, mut terminal: &mut Terminal<CrosstermBackend<Stdout
         }
     }
 
+    // Clean up the session
+    if let Some(mut s) = session.take() {
+        let _ = s.logout();
+    }
+
     Ok(())
 }
-
-pub(crate) fn fetch_inbox(config: &Config) -> Result<Vec<Email>, String> {
-    let imap_cfg = &config.imap;
-    let stream =
-        TcpStream::connect((&*imap_cfg.host, imap_cfg.port)).map_err(|e| e.to_string())?;
-    let client = imap::Client::new(stream);
-    let mut session = client
-        .login(&imap_cfg.username, &imap_cfg.password)
-        .map_err(|(e, _)| e.to_string())?;
-
-    session.select("INBOX").map_err(|e| e.to_string())?;
-
-    let mut emails = Vec::new();
-
-    let messages = session
-        .fetch("1:*", "BODY.PEEK[HEADER.FIELDS (SUBJECT FROM DATE)]")
-        .map_err(|e| e.to_string())?;
-
-    for message in messages.iter() {
-        if let Some(body) = message.header() {
-            let header = String::from_utf8_lossy(body);
-            let mut subject = String::new();
-            let mut from = String::new();
-            let mut date = String::new();
-
-            for line in header.lines() {
-                if let Some(val) = line.strip_prefix("Subject: ") {
-                    subject = val.to_string();
-                } else if let Some(val) = line.strip_prefix("From: ") {
-                    from = val.to_string();
-                } else if let Some(val) = line.strip_prefix("Date: ") {
-                    date = val.to_string();
-                }
-            }
-
-            emails.push(Email {
-                subject,
-                from,
-                date,
-            });
-        }
-    }
-
-    let _ = session.logout();
-    Ok(emails)
-}