thoughts/crates/application/src/services/federation_event.rs

use domain::{
    errors::DomainError,
    events::DomainEvent,
    models::thought::{Thought, Visibility},
    ports::{ActivityPubRepository, OutboundFederationPort, ThoughtRepository, UserRepository},
    value_objects::ThoughtId,
};
use std::sync::Arc;

pub struct FederationEventService {
    pub thoughts: Arc<dyn ThoughtRepository>,
    pub users: Arc<dyn UserRepository>,
    pub ap: Arc<dyn OutboundFederationPort>,
    pub base_url: String,
    pub federation_action: Arc<dyn domain::ports::FederationActionPort>,
    pub ap_repo: Arc<dyn ActivityPubRepository>,
    pub remote_actor_connections: Arc<dyn domain::ports::RemoteActorConnectionRepository>,
}

impl FederationEventService {
    fn object_ap_id(&self, thought: &Thought, thought_id: &ThoughtId) -> String {
        thought
            .ap_id
            .clone()
            .unwrap_or_else(|| format!("{}/thoughts/{}", self.base_url, thought_id))
    }

    pub async fn process(&self, event: &DomainEvent) -> Result<(), DomainError> {
        match event {
            DomainEvent::ThoughtCreated {
                thought_id,
                user_id,
                ..
            } => {
                let thought = match self.thoughts.find_by_id(thought_id).await? {
                    Some(t)
                        if t.local
                            && matches!(
                                t.visibility,
                                Visibility::Public | Visibility::Unlisted
                            ) =>
                    {
                        t
                    }
                    _ => return Ok(()),
                };
                let user = match self.users.find_by_id(user_id).await? {
                    Some(u) => u,
                    None => return Ok(()),
                };
                self.ap
                    .broadcast_create(user_id, &thought, user.username.as_str())
                    .await
            }

            DomainEvent::ThoughtDeleted {
                thought_id,
                user_id,
            } => {
                // No DB lookup — thought is already deleted when this event fires.
                // No locality guard: delete commands only reach local thoughts via the use case.
                let ap_id = format!("{}/thoughts/{}", self.base_url, thought_id);
                self.ap.broadcast_delete(user_id, &ap_id).await
            }

            DomainEvent::ThoughtUpdated {
                thought_id,
                user_id,
            } => {
                let thought = match self.thoughts.find_by_id(thought_id).await? {
                    Some(t)
                        if t.local
                            && matches!(
                                t.visibility,
                                Visibility::Public | Visibility::Unlisted
                            ) =>
                    {
                        t
                    }
                    _ => return Ok(()),
                };
                let user = match self.users.find_by_id(user_id).await? {
                    Some(u) => u,
                    None => return Ok(()),
                };
                self.ap
                    .broadcast_update(user_id, &thought, user.username.as_str())
                    .await
            }

            DomainEvent::BoostAdded {
                boost_id: _,
                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 = self.object_ap_id(&thought, thought_id);
                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 = self.object_ap_id(&thought, thought_id);
                self.ap
                    .broadcast_undo_announce(user_id, &object_ap_id)
                    .await
            }

            DomainEvent::FetchRemoteActorPosts {
                actor_ap_url,
                outbox_url,
            } => {
                let notes = match self
                    .federation_action
                    .fetch_outbox_page(outbox_url, 1)
                    .await
                {
                    Ok(n) => n,
                    Err(e) => {
                        tracing::warn!(outbox_url, error = %e, "failed to fetch remote outbox");
                        return Ok(());
                    }
                };

                let actor_url = url::Url::parse(actor_ap_url)
                    .map_err(|e| DomainError::ExternalService(e.to_string()))?;

                let author_id = self.ap_repo.intern_remote_actor(&actor_url).await?;

                // Resolve and cache display info so thought cards show proper names.
                let profiles = self
                    .federation_action
                    .resolve_actor_profiles(vec![actor_ap_url.clone()])
                    .await;
                if let Some(profile) = profiles.into_iter().next() {
                    let _ = self
                        .ap_repo
                        .update_remote_actor_display(
                            &author_id,
                            profile.display_name.as_deref(),
                            profile.avatar_url.as_deref(),
                        )
                        .await;
                }

                for note in notes {
                    let ap_id = match url::Url::parse(&note.ap_id) {
                        Ok(u) => u,
                        Err(_) => continue,
                    };
                    let _ = self
                        .ap_repo
                        .accept_note(
                            &ap_id,
                            &author_id,
                            &note.content,
                            note.published,
                            note.sensitive,
                            note.content_warning,
                            "public",
                        )
                        .await;
                }

                Ok(())
            }

            DomainEvent::FetchActorConnections {
                actor_ap_url,
                collection_url,
                connection_type,
                page,
            } => {
                let urls = match self
                    .federation_action
                    .fetch_actor_urls_from_collection(collection_url)
                    .await
                {
                    Ok(u) => u,
                    Err(e) => {
                        tracing::warn!(
                            collection_url,
                            error = %e,
                            "failed to fetch actor connections collection"
                        );
                        return Ok(());
                    }
                };

                if urls.is_empty() {
                    return Ok(());
                }

                let summaries = self.federation_action.resolve_actor_profiles(urls).await;

                if summaries.is_empty() {
                    return Ok(());
                }

                tracing::info!(
                    count = summaries.len(),
                    connection_type,
                    actor = actor_ap_url,
                    "caching actor connections"
                );

                self.remote_actor_connections
                    .upsert_connections(actor_ap_url, connection_type, *page, &summaries)
                    .await?;

                Ok(())
            }

            _ => Ok(()),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use async_trait::async_trait;
    use domain::{
        errors::DomainError,
        events::DomainEvent,
        models::thought::{Thought, Visibility},
        models::user::User,
        ports::{ActivityPubRepository, OutboundFederationPort},
        testing::TestStore,
        value_objects::*,
    };
    use std::sync::{Arc, Mutex};

    // ── Spy port ─────────────────────────────────────────────────────────────

    #[derive(Default)]
    struct SpyPort {
        created: Mutex<Vec<ThoughtId>>,
        deleted: Mutex<Vec<String>>,
        updated: Mutex<Vec<ThoughtId>>,
        announced: Mutex<Vec<String>>,
        undo_announced: Mutex<Vec<String>>,
    }

    #[async_trait]
    impl OutboundFederationPort for SpyPort {
        async fn broadcast_create(
            &self,
            _: &UserId,
            thought: &Thought,
            _: &str,
        ) -> Result<(), DomainError> {
            self.created.lock().unwrap().push(thought.id.clone());
            Ok(())
        }
        async fn broadcast_delete(&self, _: &UserId, ap_id: &str) -> Result<(), DomainError> {
            self.deleted.lock().unwrap().push(ap_id.to_string());
            Ok(())
        }
        async fn broadcast_update(
            &self,
            _: &UserId,
            thought: &Thought,
            _: &str,
        ) -> Result<(), DomainError> {
            self.updated.lock().unwrap().push(thought.id.clone());
            Ok(())
        }
        async fn broadcast_announce(&self, _: &UserId, ap_id: &str) -> Result<(), DomainError> {
            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 {
        User::new_local(
            UserId::new(),
            Username::new("alice").unwrap(),
            Email::new("alice@ex.com").unwrap(),
            PasswordHash("h".into()),
        )
    }

    fn local_thought(author_id: UserId) -> Thought {
        Thought::new_local(
            ThoughtId::new(),
            author_id,
            Content::new_local("hello").unwrap(),
            None,
            Visibility::Public,
            None,
            false,
        )
    }

    fn svc(store: &TestStore, spy: Arc<SpyPort>) -> FederationEventService {
        FederationEventService {
            thoughts: Arc::new(store.clone()),
            users: Arc::new(store.clone()),
            ap: spy,
            base_url: "https://example.com".to_string(),
            federation_action: Arc::new(store.clone()),
            ap_repo: Arc::new(store.clone()),
            remote_actor_connections: Arc::new(store.clone()),
        }
    }

    #[tokio::test]
    async fn thought_created_broadcasts_create() {
        let store = TestStore::default();
        let alice = alice();
        let thought = local_thought(alice.id.clone());
        store.users.lock().unwrap().push(alice.clone());
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtCreated {
                thought_id: thought.id.clone(),
                user_id: alice.id.clone(),
                in_reply_to_id: None,
            })
            .await
            .unwrap();

        assert_eq!(spy.created.lock().unwrap().len(), 1);
        assert_eq!(spy.created.lock().unwrap()[0], thought.id);
    }

    #[tokio::test]
    async fn remote_thought_created_does_not_broadcast() {
        let store = TestStore::default();
        let alice = alice();
        // Remote thought: local = false, ap_id = Some(...)
        let mut thought = local_thought(alice.id.clone());
        thought.local = false;
        thought.ap_id = Some("https://remote.example/notes/1".into());
        store.users.lock().unwrap().push(alice.clone());
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtCreated {
                thought_id: thought.id.clone(),
                user_id: alice.id.clone(),
                in_reply_to_id: None,
            })
            .await
            .unwrap();

        assert!(spy.created.lock().unwrap().is_empty());
    }

    #[tokio::test]
    async fn thought_deleted_broadcasts_delete_with_constructed_ap_id() {
        let store = TestStore::default();
        let alice = alice();
        let tid = ThoughtId::new();

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtDeleted {
                thought_id: tid.clone(),
                user_id: alice.id.clone(),
            })
            .await
            .unwrap();

        let deleted = spy.deleted.lock().unwrap();
        assert_eq!(deleted.len(), 1);
        assert_eq!(deleted[0], format!("https://example.com/thoughts/{}", tid));
    }

    #[tokio::test]
    async fn thought_updated_broadcasts_update() {
        let store = TestStore::default();
        let alice = alice();
        let thought = local_thought(alice.id.clone());
        store.users.lock().unwrap().push(alice.clone());
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtUpdated {
                thought_id: thought.id.clone(),
                user_id: alice.id.clone(),
            })
            .await
            .unwrap();

        assert_eq!(spy.updated.lock().unwrap().len(), 1);
        assert_eq!(spy.updated.lock().unwrap()[0], thought.id);
    }

    #[tokio::test]
    async fn boost_of_local_thought_announces_constructed_url() {
        let store = TestStore::default();
        let alice = alice();
        let thought = local_thought(alice.id.clone()); // ap_id = None
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::BoostAdded {
                boost_id: BoostId::new(),
                user_id: alice.id.clone(),
                thought_id: thought.id.clone(),
            })
            .await
            .unwrap();

        let announced = spy.announced.lock().unwrap();
        assert_eq!(announced.len(), 1);
        assert_eq!(
            announced[0],
            format!("https://example.com/thoughts/{}", thought.id)
        );
    }

    #[tokio::test]
    async fn boost_of_remote_thought_announces_remote_ap_id() {
        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/123".into());
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::BoostAdded {
                boost_id: BoostId::new(),
                user_id: alice.id.clone(),
                thought_id: thought.id.clone(),
            })
            .await
            .unwrap();

        let announced = spy.announced.lock().unwrap();
        assert_eq!(
            announced[0],
            "https://mastodon.social/users/bob/statuses/123"
        );
    }

    #[tokio::test]
    async fn direct_thought_created_does_not_broadcast() {
        let store = TestStore::default();
        let alice = alice();
        let thought = Thought::new_local(
            ThoughtId::new(),
            alice.id.clone(),
            Content::new_local("private").unwrap(),
            None,
            Visibility::Direct,
            None,
            false,
        );
        store.users.lock().unwrap().push(alice.clone());
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtCreated {
                thought_id: thought.id.clone(),
                user_id: alice.id.clone(),
                in_reply_to_id: None,
            })
            .await
            .unwrap();

        assert!(spy.created.lock().unwrap().is_empty());
    }

    #[tokio::test]
    async fn followers_only_thought_does_not_broadcast_publicly() {
        let store = TestStore::default();
        let alice = alice();
        let thought = Thought::new_local(
            ThoughtId::new(),
            alice.id.clone(),
            Content::new_local("for followers").unwrap(),
            None,
            Visibility::Followers,
            None,
            false,
        );
        store.users.lock().unwrap().push(alice.clone());
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtCreated {
                thought_id: thought.id.clone(),
                user_id: alice.id.clone(),
                in_reply_to_id: None,
            })
            .await
            .unwrap();

        assert!(spy.created.lock().unwrap().is_empty());
    }

    #[tokio::test]
    async fn unrelated_events_are_noop() {
        let store = TestStore::default();
        let spy = Arc::new(SpyPort::default());
        let svc = svc(&store, spy.clone());

        svc.process(&DomainEvent::UserBlocked {
            blocker_id: UserId::new(),
            blocked_id: UserId::new(),
        })
        .await
        .unwrap();

        assert!(spy.created.lock().unwrap().is_empty());
        assert!(spy.deleted.lock().unwrap().is_empty());
        assert!(spy.updated.lock().unwrap().is_empty());
        assert!(spy.announced.lock().unwrap().is_empty());
    }

    #[tokio::test]
    async fn thought_created_does_not_broadcast_if_user_missing() {
        let store = TestStore::default();
        let alice = alice();
        let thought = local_thought(alice.id.clone());
        // Don't push alice into users — simulates user deleted before handler runs
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtCreated {
                thought_id: thought.id.clone(),
                user_id: alice.id.clone(),
                in_reply_to_id: None,
            })
            .await
            .unwrap();

        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 boost_removed_does_not_broadcast_if_thought_missing() {
        let store = TestStore::default();
        let alice = alice();
        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::BoostRemoved {
                user_id: alice.id.clone(),
                thought_id: ThoughtId::new(), // doesn't exist in store
            })
            .await
            .unwrap();
        assert!(spy.undo_announced.lock().unwrap().is_empty());
    }

    #[tokio::test]
    async fn thought_updated_does_not_broadcast_if_user_missing() {
        let store = TestStore::default();
        let alice = alice();
        let thought = local_thought(alice.id.clone());
        // Don't push alice into users
        store.thoughts.lock().unwrap().push(thought.clone());

        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::ThoughtUpdated {
                thought_id: thought.id.clone(),
                user_id: alice.id.clone(),
            })
            .await
            .unwrap();

        assert!(spy.updated.lock().unwrap().is_empty());
    }

    #[tokio::test]
    async fn fetch_remote_actor_posts_is_noop_when_outbox_empty() {
        let store = TestStore::default();
        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::FetchRemoteActorPosts {
                actor_ap_url: "https://mastodon.social/users/alice".into(),
                outbox_url: "https://mastodon.social/users/alice/outbox".into(),
            })
            .await
            .unwrap();
        // TestStore.fetch_outbox_page returns Ok(vec![]) — no notes, no error
    }

    #[tokio::test]
    async fn fetch_actor_connections_is_noop_when_collection_empty() {
        let store = TestStore::default();
        let spy = Arc::new(SpyPort::default());
        svc(&store, spy.clone())
            .process(&DomainEvent::FetchActorConnections {
                actor_ap_url: "https://mastodon.social/users/alice".into(),
                collection_url: "https://mastodon.social/users/alice/followers".into(),
                connection_type: "followers".into(),
                page: 1,
            })
            .await
            .unwrap();
    }
}