Add ForceMention mrf

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

lib/pleroma/web/activity_pub/mrf/force_mention.ex

@@ -0,0 +1,59 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2024 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.ActivityPub.MRF.ForceMention do
+  require Pleroma.Constants
+
+  alias Pleroma.Config
+  alias Pleroma.Object
+  alias Pleroma.User
+
+  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
+
+  defp get_author(url) do
+    with %Object{data: %{"actor" => actor}} <- Object.normalize(url, fetch: false),
+         %User{ap_id: ap_id, nickname: nickname} <- User.get_cached_by_ap_id(actor) do
+      %{"type" => "Mention", "href" => ap_id, "name" => "@#{nickname}"}
+    else
+      _ -> nil
+    end
+  end
+
+  defp prepend_author(tags, _, false), do: tags
+
+  defp prepend_author(tags, nil, _), do: tags
+
+  defp prepend_author(tags, url, _) do
+    actor = get_author(url)
+
+    if not is_nil(actor) do
+      [actor | tags]
+    else
+      tags
+    end
+  end
+
+  @impl true
+  def filter(%{"type" => "Create", "object" => %{"tag" => tag} = object} = activity) do
+    tag =
+      tag
+      |> prepend_author(
+        object["inReplyTo"],
+        Config.get([:mrf_force_mention, :mention_parent, true])
+      )
+      |> prepend_author(
+        object["quoteUrl"],
+        Config.get([:mrf_force_mention, :mention_quoted, true])
+      )
+      |> Enum.uniq()
+
+    {:ok, put_in(activity["object"]["tag"], tag)}
+  end
+
+  @impl true
+  def filter(object), do: {:ok, object}
+
+  @impl true
+  def describe, do: {:ok, %{}}
+end