server: poll for new messages and update clients via WS

server/src/bin/letterbox-server.rs

@@ -1,7 +1,7 @@
 // Rocket generates a lot of warnings for handlers
 // TODO: figure out why
 #![allow(unreachable_patterns)]
-use std::{error::Error, io::Cursor, net::SocketAddr, str::FromStr, sync::Arc};
+use std::{error::Error, io::Cursor, net::SocketAddr, str::FromStr, sync::Arc, time::Duration};
 
 use async_graphql::{extensions, http::GraphiQLSource, Schema};
 use async_graphql_axum::{GraphQL, GraphQLSubscription};
@@ -21,7 +21,9 @@ use letterbox_server::tantivy::TantivyConnection;
 use letterbox_server::{
     config::Config,
     error::ServerError,
-    graphql::{Attachment, GraphqlSchema, MutationRoot, QueryRoot, SubscriptionRoot},
+    graphql::{
+        compute_catchup_ids, Attachment, GraphqlSchema, MutationRoot, QueryRoot, SubscriptionRoot,
+    },
     nm::{attachment_bytes, cid_attachment_bytes},
     ws::ConnectionTracker,
 };
@@ -294,19 +296,44 @@ async fn main() -> Result<(), Box<dyn Error>> {
         std::fs::create_dir_all(&config.slurp_cache_path)?;
     }
     let pool = PgPool::connect(&config.newsreader_database_url).await?;
+    let nm = Notmuch::default();
     sqlx::migrate!("./migrations").run(&pool).await?;
     #[cfg(feature = "tantivy")]
     let tantivy_conn = TantivyConnection::new(&config.newsreader_tantivy_db_path)?;
 
     let cacher = FilesystemCacher::new(&config.slurp_cache_path)?;
     let schema = Schema::build(QueryRoot, MutationRoot, SubscriptionRoot)
-        .data(Notmuch::default())
+        .data(nm.clone())
         .data(cacher)
         .data(pool.clone());
 
     let schema = schema.extension(extensions::Logger).finish();
 
     let conn_tracker = Arc::new(Mutex::new(ConnectionTracker::default()));
+    async fn watch_new(
+        nm: Notmuch,
+        pool: PgPool,
+        conn_tracker: Arc<Mutex<ConnectionTracker>>,
+        poll_time: Duration,
+    ) -> Result<(), async_graphql::Error> {
+        let mut old_ids = Vec::new();
+        loop {
+            let ids = compute_catchup_ids(&nm, &pool, "is:unread").await?;
+            if old_ids != ids {
+                info!("old_ids: {old_ids:?}\n     ids: {ids:?}");
+                conn_tracker
+                    .lock()
+                    .await
+                    .send_message_all(WebsocketMessage::RefreshMessages)
+                    .await
+            }
+            old_ids = ids;
+            tokio::time::sleep(poll_time).await;
+        }
+    }
+    let ct = Arc::clone(&conn_tracker);
+    let poll_time = Duration::from_secs(10);
+    let _h = tokio::spawn(watch_new(nm, pool, ct, poll_time));
 
     let app = Router::new()
         .route("/test", get(test_handler))