feat: BoostRemoved → Undo(Announce) fan-out via OutboundFederationPort

crates/application/src/services/federation_event.rs

@@ -58,6 +58,17 @@ impl FederationEventService {
                 self.ap.broadcast_announce(user_id, &object_ap_id).await
             }
 
+            DomainEvent::BoostRemoved { user_id, thought_id } => {
+                let thought = match self.thoughts.find_by_id(thought_id).await? {
+                    Some(t) => t,
+                    None => return Ok(()),
+                };
+                let object_ap_id = thought.ap_id.clone().unwrap_or_else(|| {
+                    format!("{}/thoughts/{}", self.base_url, thought_id)
+                });
+                self.ap.broadcast_undo_announce(user_id, &object_ap_id).await
+            }
+
             _ => Ok(()),
         }
     }
@@ -82,10 +93,11 @@ mod tests {
 
     #[derive(Default)]
     struct SpyPort {
-        created:   Mutex<Vec<ThoughtId>>,
-        deleted:   Mutex<Vec<String>>,
-        updated:   Mutex<Vec<ThoughtId>>,
-        announced: Mutex<Vec<String>>,
+        created:        Mutex<Vec<ThoughtId>>,
+        deleted:        Mutex<Vec<String>>,
+        updated:        Mutex<Vec<ThoughtId>>,
+        announced:      Mutex<Vec<String>>,
+        undo_announced: Mutex<Vec<String>>,
     }
 
     #[async_trait]
@@ -106,6 +118,10 @@ mod tests {
             self.announced.lock().unwrap().push(ap_id.to_string());
             Ok(())
         }
+        async fn broadcast_undo_announce(&self, _: &UserId, ap_id: &str) -> Result<(), DomainError> {
+            self.undo_announced.lock().unwrap().push(ap_id.to_string());
+            Ok(())
+        }
     }
 
     fn alice() -> User {
@@ -354,6 +370,50 @@ mod tests {
         assert!(spy.created.lock().unwrap().is_empty());
     }
 
+    #[tokio::test]
+    async fn boost_removed_sends_undo_announce_for_local_thought() {
+        let store = TestStore::default();
+        let alice = alice();
+        let thought = local_thought(alice.id.clone()); // ap_id = None → constructed URL
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::BoostRemoved {
+                user_id: alice.id.clone(),
+                thought_id: thought.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        let undo_announced = spy.undo_announced.lock().unwrap();
+        assert_eq!(undo_announced.len(), 1);
+        assert_eq!(undo_announced[0], format!("https://example.com/thoughts/{}", thought.id));
+    }
+
+    #[tokio::test]
+    async fn boost_removed_sends_undo_announce_for_remote_thought() {
+        let store = TestStore::default();
+        let alice = alice();
+        let mut thought = local_thought(alice.id.clone());
+        thought.local = false;
+        thought.ap_id = Some("https://mastodon.social/users/bob/statuses/456".into());
+        store.thoughts.lock().unwrap().push(thought.clone());
+
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::BoostRemoved {
+                user_id: alice.id.clone(),
+                thought_id: thought.id.clone(),
+            })
+            .await
+            .unwrap();
+
+        let undo_announced = spy.undo_announced.lock().unwrap();
+        assert_eq!(undo_announced.len(), 1);
+        assert_eq!(undo_announced[0], "https://mastodon.social/users/bob/statuses/456");
+    }
+
     #[tokio::test]
     async fn thought_updated_does_not_broadcast_if_user_missing() {
         let store = TestStore::default();