From 56861d64836499af0e5950c27078b3d2e1364b86 Mon Sep 17 00:00:00 2001
From: Thomas Citharel <tcit@tcit.fr>
Date: Tue, 10 Aug 2021 11:35:12 +0200
Subject: [PATCH] Fix audience for comments under a remote event from group

Signed-off-by: Thomas Citharel <tcit@tcit.fr>
---
 lib/federation/activity_pub/audience.ex       | 31 ++++++++++++-------
 .../federation/activity_pub/audience_test.exs | 26 ++++++++++++++++
 2 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/lib/federation/activity_pub/audience.ex b/lib/federation/activity_pub/audience.ex
index fb98f1e23..e78513050 100644
--- a/lib/federation/activity_pub/audience.ex
+++ b/lib/federation/activity_pub/audience.ex
@@ -52,16 +52,14 @@ defmodule Mobilizon.Federation.ActivityPub.Audience do
       }) do
     with {to, cc} <-
            extract_actors_from_mentions(mentions, actor, visibility),
-         {to, cc} <- {Enum.uniq(to ++ add_in_reply_to(in_reply_to_comment)), cc},
-         {to, cc} <- {Enum.uniq(to ++ add_event_author(event)), cc},
+         {to, cc} <- {to ++ add_in_reply_to(in_reply_to_comment), cc},
+         {to, cc} <- add_event_organizers(event, to, cc),
          {to, cc} <-
            {to,
-            Enum.uniq(
-              cc ++
-                add_comments_authors([origin_comment]) ++
-                add_shares_actors_followers(url)
-            )} do
-      %{"to" => to, "cc" => cc}
+            cc ++
+              add_comments_authors([origin_comment]) ++
+              add_shares_actors_followers(url)} do
+      %{"to" => Enum.uniq(to), "cc" => Enum.uniq(cc)}
     end
   end
 
@@ -173,11 +171,22 @@ defmodule Mobilizon.Federation.ActivityPub.Audience do
   defp add_in_reply_to(%Event{organizer_actor: %Actor{url: url}} = _event), do: [url]
   defp add_in_reply_to(_), do: []
 
-  defp add_event_author(%Event{} = event) do
-    [Repo.preload(event, [:organizer_actor]).organizer_actor.url]
+  defp add_event_organizers(%Event{} = event, to, cc) do
+    event = Repo.preload(event, [:organizer_actor, :attributed_to])
+
+    case event do
+      %Event{
+        attributed_to: %Actor{members_url: members_url, followers_url: followers_url},
+        organizer_actor: %Actor{url: organizer_actor_url}
+      } ->
+        {to ++ [organizer_actor_url, members_url], cc ++ [followers_url]}
+
+      %Event{organizer_actor: %Actor{url: organizer_actor_url}} ->
+        {to ++ [organizer_actor_url], cc}
+    end
   end
 
-  defp add_event_author(_), do: []
+  defp add_event_organizers(_, to, cc), do: {to, cc}
 
   defp add_comment_author(%Comment{} = comment) do
     case Repo.preload(comment, [:actor]) do
diff --git a/test/federation/activity_pub/audience_test.exs b/test/federation/activity_pub/audience_test.exs
index bf16bc0da..4549698c9 100644
--- a/test/federation/activity_pub/audience_test.exs
+++ b/test/federation/activity_pub/audience_test.exs
@@ -247,6 +247,32 @@ defmodule Mobilizon.Federation.ActivityPub.AudienceTest do
       assert %{"to" => [members_url], "cc" => []} ==
                Audience.get_audience(comment)
     end
+
+    test "reply to a remote comment" do
+      %Actor{id: remote_actor_id, url: remote_actor_url} =
+        remote_actor =
+        insert(:actor, domain: "somewhere.else", url: "https://somewhere.else/@someone")
+
+      %Actor{id: remote_group_id, url: remote_group_url} =
+        remote_group =
+        insert(:group, domain: "somewhere.else", url: "https://somewhere.else/@somegroup")
+
+      %Event{} =
+        event =
+        insert(:event, local: false, organizer_actor: remote_actor, attributed_to: remote_group)
+
+      %Comment{} = comment = insert(:comment, event: event)
+
+      assert %{
+               "cc" => [comment.actor.followers_url, comment.event.attributed_to.followers_url],
+               "to" => [
+                 @ap_public,
+                 comment.event.organizer_actor.url,
+                 comment.event.attributed_to.members_url
+               ]
+             } ==
+               Audience.get_audience(comment)
+    end
   end
 
   describe "participant" do