From ab9184f068733d152b6d91accf748c9d72d48fe0 Mon Sep 17 00:00:00 2001
From: silverpill <silverpill@firemail.cc>
Date: Mon, 1 Nov 2021 00:23:02 +0000
Subject: [PATCH] Send Create(Note) to author of parent post when creating
 reply

---
 src/activitypub/activity.rs        | 24 +++++++++++++++++++-----
 src/activitypub/deliverer.rs       |  9 +++++++--
 src/mastodon_api/statuses/views.rs | 11 +++++++++--
 3 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/src/activitypub/activity.rs b/src/activitypub/activity.rs
index 7593a31..cb0f81e 100644
--- a/src/activitypub/activity.rs
+++ b/src/activitypub/activity.rs
@@ -121,13 +121,19 @@ pub fn create_note(
             url,
         }
     }).collect();
+    let mut recipients = vec![AP_PUBLIC.to_string()];
     let in_reply_to_object_id = match post.in_reply_to_id {
         Some(in_reply_to_id) => {
             let post = in_reply_to.unwrap();
             assert_eq!(post.id, in_reply_to_id);
-            match post.author.is_local() {
-                false => post.object_id.clone(),
-                true => Some(get_object_url(instance_url, &post.id)),
+            match post.author.actor_json {
+                Some(ref actor_value) => {
+                    // Replying to remote post
+                    let remote_actor_id = actor_value["id"].as_str().unwrap();
+                    recipients.push(remote_actor_id.to_string());
+                    post.object_id.clone()
+                },
+                None => Some(get_object_url(instance_url, &post.id)),
             }
         },
         None => None,
@@ -143,7 +149,7 @@ pub fn create_note(
         attributed_to: Some(actor_id),
         in_reply_to: in_reply_to_object_id,
         content: Some(post.content.clone()),
-        to: Some(json!(AP_PUBLIC)),
+        to: Some(json!(recipients)),
     }
 }
 
@@ -324,12 +330,16 @@ mod tests {
             note.in_reply_to.unwrap(),
             format!("{}/objects/{}", INSTANCE_URL, parent.id),
         );
+        assert_eq!(note.to.unwrap(), json!([AP_PUBLIC]));
     }
 
     #[test]
     fn test_create_note_with_remote_parent() {
+        let parent_author_actor_id = "https://test.net/user/test";
         let parent_author = DbActorProfile {
-            actor_json: Some(json!("test")),
+            actor_json: Some(json!({
+                "id": parent_author_actor_id,
+            })),
             ..Default::default()
         };
         let parent = Post {
@@ -347,6 +357,10 @@ mod tests {
             note.in_reply_to.unwrap(),
             parent.object_id.unwrap(),
         );
+        assert_eq!(
+            note.to.unwrap(),
+            json!([AP_PUBLIC, parent_author_actor_id]),
+        );
     }
 
     #[test]
diff --git a/src/activitypub/deliverer.rs b/src/activitypub/deliverer.rs
index b7c5a0e..3433beb 100644
--- a/src/activitypub/deliverer.rs
+++ b/src/activitypub/deliverer.rs
@@ -90,14 +90,19 @@ async fn deliver_activity_worker(
         ),
     );
     let activity_json = serde_json::to_string(&activity)?;
-    for recipient in recipients {
+    let mut inboxes: Vec<String> = recipients.into_iter()
+        .map(|actor| actor.inbox)
+        .collect();
+    inboxes.sort();
+    inboxes.dedup();
+    for inbox_url in inboxes {
         // TODO: retry on error
         if let Err(err) = send_activity(
             &config,
             &actor_key,
             &actor_key_id,
             &activity_json,
-            &recipient.inbox,
+            &inbox_url,
         ).await {
             log::error!("{}", err);
         }
diff --git a/src/mastodon_api/statuses/views.rs b/src/mastodon_api/statuses/views.rs
index dfb984a..7f3865d 100644
--- a/src/mastodon_api/statuses/views.rs
+++ b/src/mastodon_api/statuses/views.rs
@@ -49,7 +49,7 @@ async fn create_status(
     post_data.validate()?;
     let post = create_post(db_client, &current_user.id, post_data).await?;
     // Federate
-    let in_reply_to = match post.in_reply_to_id {
+    let maybe_in_reply_to = match post.in_reply_to_id {
         Some(in_reply_to_id) => {
             let in_reply_to = get_post_by_id(db_client, &in_reply_to_id).await?;
             Some(in_reply_to)
@@ -59,7 +59,7 @@ async fn create_status(
     let activity = create_activity_note(
         &config.instance_url(),
         &post,
-        in_reply_to.as_ref(),
+        maybe_in_reply_to.as_ref(),
     );
     let followers = get_followers(db_client, &current_user.id).await?;
     let mut recipients: Vec<Actor> = Vec::new();
@@ -70,6 +70,13 @@ async fn create_status(
             recipients.push(remote_actor);
         };
     };
+    if let Some(in_reply_to) = maybe_in_reply_to {
+        let maybe_remote_actor = in_reply_to.author.actor()
+            .map_err(|_| HttpError::InternalError)?;
+        if let Some(remote_actor) = maybe_remote_actor {
+            recipients.push(remote_actor);
+        }
+    }
     deliver_activity(&config, &current_user, activity, recipients);
     let status = Status::from_post(post, &config.instance_url());
     Ok(HttpResponse::Created().json(status))