support DM target via 'dm: @user:server' frontmatter, finds or creates DM room

src/main.rs

@@ -550,7 +550,21 @@ async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {
 
         match invoke_claude(&room_id, &room_name, &chat_msgs, seen_idx, &model).await {
             Ok(Some(response)) => {
-                if let Some(target_room) = client.get_room(&response.room) {
+                let target_room = match &response.target {
+                    ResponseTarget::Room(rid) => client.get_room(rid),
+                    ResponseTarget::Dm(user) => match find_or_create_dm(&client, user).await {
+                        Ok(r) => Some(r),
+                        Err(e) => {
+                            tracing::error!(user = %user, "failed to get/create DM: {e}");
+                            None
+                        }
+                    },
+                };
+                let target_label = match &response.target {
+                    ResponseTarget::Room(rid) => rid.to_string(),
+                    ResponseTarget::Dm(user) => format!("dm:{user}"),
+                };
+                if let Some(target_room) = target_room {
                     let content = RoomMessageEventContent::text_plain(&response.body);
                     match target_room.send(content).await {
                         Ok(_) => {
@@ -560,7 +574,7 @@ async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {
                                 state.last_shown.insert(room_id.clone(), eid);
                             }
                             tracing::info!(
-                                room = %response.room,
+                                target = %target_label,
                                 "sent response ({} budget remaining)",
                                 state.rate_budget
                             );
@@ -570,7 +584,7 @@ async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {
                         Err(e) => tracing::error!("failed to send: {e}"),
                     }
                 } else {
-                    tracing::warn!(room = %response.room, "target room not found");
+                    tracing::warn!(target = %target_label, "target not available");
                 }
             }
             Ok(None) => {
@@ -590,6 +604,22 @@ async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {
     }
 }
 
+/// Find an existing DM room with the given user, or create one.
+async fn find_or_create_dm(client: &Client, user_id: &UserId) -> anyhow::Result<Room> {
+    for room in client.joined_rooms() {
+        if room.is_direct().await.unwrap_or(false)
+            && room
+                .direct_targets()
+                .iter()
+                .any(|t| t.as_str() == user_id.as_str())
+        {
+            return Ok(room);
+        }
+    }
+    tracing::info!(user = %user_id, "creating new DM room");
+    Ok(client.create_dm(user_id).await?)
+}
+
 async fn send_read_receipt(room: &Room, event_id: Option<OwnedEventId>) {
     let Some(eid) = event_id else {
         return;
@@ -685,8 +715,13 @@ async fn fetch_message(
     ))
 }
 
+enum ResponseTarget {
+    Room(OwnedRoomId),
+    Dm(OwnedUserId),
+}
+
 struct ClaudeResponse {
-    room: OwnedRoomId,
+    target: ResponseTarget,
     body: String,
 }
 
@@ -804,19 +839,31 @@ fn parse_response(raw: &str, default_room: &OwnedRoomId) -> Option<ClaudeRespons
                 return None;
             }
 
-            let room = frontmatter
+            // dm: takes precedence over room: if both set
+            let dm = frontmatter
                 .lines()
-                .find(|l| l.starts_with("room:"))
-                .and_then(|l| l.strip_prefix("room:"))
-                .and_then(|r| r.trim().parse().ok())
-                .unwrap_or_else(|| default_room.clone());
+                .find(|l| l.starts_with("dm:"))
+                .and_then(|l| l.strip_prefix("dm:"))
+                .and_then(|r| r.trim().parse::<OwnedUserId>().ok());
+
+            let target = if let Some(user) = dm {
+                ResponseTarget::Dm(user)
+            } else {
+                let room = frontmatter
+                    .lines()
+                    .find(|l| l.starts_with("room:"))
+                    .and_then(|l| l.strip_prefix("room:"))
+                    .and_then(|r| r.trim().parse().ok())
+                    .unwrap_or_else(|| default_room.clone());
+                ResponseTarget::Room(room)
+            };
 
             if body.is_empty() {
                 return None;
             }
 
             return Some(ClaudeResponse {
-                room,
+                target,
                 body: body.to_owned(),
             });
         }
@@ -827,7 +874,7 @@ fn parse_response(raw: &str, default_room: &OwnedRoomId) -> Option<ClaudeRespons
     }
 
     Some(ClaudeResponse {
-        room: default_room.clone(),
+        target: ResponseTarget::Room(default_room.clone()),
         body: trimmed.to_owned(),
     })
 }
@@ -840,11 +887,18 @@ mod tests {
         "!test:example.com".parse().unwrap()
     }
 
+    fn assert_room(resp: &ClaudeResponse, expected: &str) {
+        match &resp.target {
+            ResponseTarget::Room(r) => assert_eq!(r.as_str(), expected),
+            ResponseTarget::Dm(_) => panic!("expected room target, got dm"),
+        }
+    }
+
     #[test]
     fn parse_frontmatter_response() {
         let raw = "---\nroom: !other:server\n---\nhello world";
         let resp = parse_response(raw, &test_room()).unwrap();
-        assert_eq!(resp.room.as_str(), "!other:server");
+        assert_room(&resp, "!other:server");
         assert_eq!(resp.body, "hello world");
     }
 
@@ -858,7 +912,7 @@ mod tests {
     fn parse_plain_response() {
         let raw = "just a message";
         let resp = parse_response(raw, &test_room()).unwrap();
-        assert_eq!(resp.room, test_room());
+        assert_room(&resp, "!test:example.com");
         assert_eq!(resp.body, "just a message");
     }
 
@@ -872,6 +926,27 @@ mod tests {
     fn parse_default_room() {
         let raw = "---\n---\nhello";
         let resp = parse_response(raw, &test_room()).unwrap();
-        assert_eq!(resp.room, test_room());
+        assert_room(&resp, "!test:example.com");
+    }
+
+    #[test]
+    fn parse_dm_response() {
+        let raw = "---\ndm: @alice:example.com\n---\nhi alice";
+        let resp = parse_response(raw, &test_room()).unwrap();
+        match &resp.target {
+            ResponseTarget::Dm(u) => assert_eq!(u.as_str(), "@alice:example.com"),
+            ResponseTarget::Room(_) => panic!("expected dm target"),
+        }
+        assert_eq!(resp.body, "hi alice");
+    }
+
+    #[test]
+    fn parse_dm_takes_precedence_over_room() {
+        let raw = "---\nroom: !other:server\ndm: @bob:example.com\n---\nhello";
+        let resp = parse_response(raw, &test_room()).unwrap();
+        match &resp.target {
+            ResponseTarget::Dm(u) => assert_eq!(u.as_str(), "@bob:example.com"),
+            ResponseTarget::Room(_) => panic!("expected dm target"),
+        }
     }
 }