1 files changed, 45 insertions, 0 deletions
diff --git a/lib/pleroma/web/activity_pub/utils.ex b/lib/pleroma/web/activity_pub/utils.ex
index 7a0762e9f..1f740eda5 100644
--- a/lib/pleroma/web/activity_pub/utils.ex
+++ b/lib/pleroma/web/activity_pub/utils.ex
@@ -237,6 +237,28 @@ defmodule Pleroma.Web.ActivityPub.Utils do
   #### Announce-related helpers
 
   @doc """
+  Retruns an existing announce activity if the notice has already been announced
+  """
+  def get_existing_announce(actor, %{data: %{"id" => id}}) do
+    query =
+      from(
+        activity in Activity,
+        where: fragment("(?)->>'actor' = ?", activity.data, ^actor),
+        # this is to use the index
+        where:
+          fragment(
+            "coalesce((?)->'object'->>'id', (?)->>'object') = ?",
+            activity.data,
+            activity.data,
+            ^id
+          ),
+        where: fragment("(?)->>'type' = 'Announce'", activity.data)
+      )
+
+    Repo.one(query)
+  end
+
+  @doc """
   Make announce activity data for the given actor and object
   """
   def make_announce_data(
@@ -256,12 +278,35 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     if activity_id, do: Map.put(data, "id", activity_id), else: data
   end
 
+  @doc """
+  Make unannounce activity data for the given actor and object
+  """
+  def make_unannounce_data(
+        %User{ap_id: ap_id} = user,
+        %Object{data: %{"id" => id, "context" => context}} = object
+      ) do
+    %{
+      "type" => "Undo",
+      "actor" => ap_id,
+      "object" => id,
+      "to" => [user.follower_address, object.data["actor"]],
+      "cc" => ["https://www.w3.org/ns/activitystreams#Public"],
+      "context" => context
+    }
+  end
+
   def add_announce_to_object(%Activity{data: %{"actor" => actor}}, object) do
     with announcements <- [actor | object.data["announcements"] || []] |> Enum.uniq() do
       update_element_in_object("announcement", announcements, object)
     end
   end
 
+  def remove_announce_from_object(%Activity{data: %{"actor" => actor}}, object) do
+    with announcements <- (object.data["announcements"] || []) |> List.delete(actor) do
+      update_element_in_object("announcement", announcements, object)
+    end
+  end
+
   #### Unfollow-related helpers
 
   def make_unfollow_data(follower, followed, follow_activity) do