feat: implement remote unfollow — wire FederationActionPort through delete_follow handler

crates/adapters/activitypub-base/src/service.rs

@@ -1418,6 +1418,21 @@ impl domain::ports::FederationActionPort for ActivityPubService {
             .map_err(|e| domain::errors::DomainError::ExternalService(e.to_string()))
     }
 
+    async fn unfollow_remote(
+        &self,
+        local_user_id: &domain::value_objects::UserId,
+        handle: &str,
+    ) -> Result<(), domain::errors::DomainError> {
+        let data = self.federation_config.to_request_data();
+        let remote_actor: DbActor = webfinger_resolve_actor(handle, &data).await.map_err(|e| {
+            domain::errors::DomainError::ExternalService(anyhow::anyhow!("{e}").to_string())
+        })?;
+        let actor_url = remote_actor.ap_id.to_string();
+        self.unfollow(local_user_id.as_uuid(), &actor_url)
+            .await
+            .map_err(|e| domain::errors::DomainError::ExternalService(e.to_string()))
+    }
+
     async fn actor_json(
         &self,
         user_id: &domain::value_objects::UserId,

crates/application/src/use_cases/social.rs

@@ -137,6 +137,27 @@ pub async fn follow_user(
     Ok(())
 }
 
+pub async fn unfollow_actor(
+    follows: &dyn FollowRepository,
+    users: &dyn UserRepository,
+    federation: &dyn FederationActionPort,
+    events: &dyn EventPublisher,
+    follower_id: &UserId,
+    username: &str,
+) -> Result<(), DomainError> {
+    if username.contains('@') {
+        federation.unfollow_remote(follower_id, username).await
+    } else {
+        let uname = Username::new(username)
+            .map_err(|_| DomainError::InvalidInput("invalid username".into()))?;
+        let target = users
+            .find_by_username(&uname)
+            .await?
+            .ok_or(DomainError::NotFound)?;
+        unfollow_user(follows, events, follower_id, &target.id).await
+    }
+}
+
 pub async fn unfollow_user(
     follows: &dyn FollowRepository,
     events: &dyn EventPublisher,
@@ -370,6 +391,48 @@ mod tests {
         assert!(store.follows.lock().unwrap().is_empty());
     }
 
+    #[tokio::test]
+    async fn unfollow_actor_local_routes_to_unfollow_user() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        let bob = user("bob");
+        store.users.lock().unwrap().push(bob.clone());
+        // Create an existing follow first
+        store
+            .follows
+            .lock()
+            .unwrap()
+            .push(domain::models::social::Follow {
+                follower_id: alice.id.clone(),
+                following_id: bob.id.clone(),
+                state: domain::models::social::FollowState::Accepted,
+                ap_id: None,
+                created_at: chrono::Utc::now(),
+            });
+        unfollow_actor(&store, &store, &store, &store, &alice.id, "bob")
+            .await
+            .unwrap();
+        assert!(store.follows.lock().unwrap().is_empty());
+    }
+
+    #[tokio::test]
+    async fn unfollow_actor_remote_routes_to_federation() {
+        let store = TestStore::default();
+        let alice = user("alice");
+        unfollow_actor(
+            &store,
+            &store,
+            &store,
+            &store,
+            &alice.id,
+            "@bob@example.com",
+        )
+        .await
+        .unwrap();
+        // TestStore.unfollow_remote is a no-op — just verify it doesn't error
+        assert!(store.follows.lock().unwrap().is_empty());
+    }
+
     #[tokio::test]
     async fn boost_and_unboost() {
         let store = TestStore::default();

crates/domain/src/ports.rs

@@ -223,6 +223,11 @@ pub trait RemoteActorConnectionRepository: Send + Sync {
 pub trait FederationActionPort: Send + Sync {
     async fn lookup_actor(&self, handle: &str) -> Result<RemoteActor, DomainError>;
     async fn follow_remote(&self, local_user_id: &UserId, handle: &str) -> Result<(), DomainError>;
+    async fn unfollow_remote(
+        &self,
+        local_user_id: &UserId,
+        handle: &str,
+    ) -> Result<(), DomainError>;
     async fn actor_json(&self, user_id: &UserId) -> Result<String, DomainError>;
     async fn followers_collection_json(
         &self,

crates/domain/src/testing.rs

@@ -548,6 +548,14 @@ impl FederationActionPort for TestStore {
         Ok(())
     }
 
+    async fn unfollow_remote(
+        &self,
+        _local_user_id: &UserId,
+        _handle: &str,
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
     async fn actor_json(&self, _user_id: &UserId) -> Result<String, DomainError> {
         Err(DomainError::NotFound)
     }

crates/presentation/src/handlers/social.rs

@@ -79,13 +79,15 @@ pub async fn delete_follow(
     AuthUser(uid): AuthUser,
     Path(username): Path<String>,
 ) -> Result<StatusCode, ApiError> {
-    if username.contains('@') {
-        return Err(ApiError::BadRequest(
-            "remote unfollow not yet supported".into(),
-        ));
-    }
-    let target = get_user_by_username(&*s.users, &username).await?;
-    unfollow_user(&*s.follows, &*s.events, &uid, &target.id).await?;
+    unfollow_actor(
+        &*s.follows,
+        &*s.users,
+        &*s.federation,
+        &*s.events,
+        &uid,
+        &username,
+    )
+    .await?;
     Ok(StatusCode::NO_CONTENT)
 }
 #[utoipa::path(post, path = "/users/{username}/block", params(("username" = String, Path, description = "Username")), responses((status = 204, description = "Blocked")), security(("bearer_auth" = [])))]