Use pseudo ap id of a list in BCC

lib/pleroma/list.ex

@@ -12,6 +12,8 @@ defmodule Pleroma.List do
   alias Pleroma.Repo
   alias Pleroma.User
 
+  @ap_id_regex ~r/^\/users\/(?<nickname>\w+)\/lists\/(?<list_id>\d+)/
+
   schema "lists" do
     belongs_to(:user, User, type: Pleroma.FlakeId)
     field(:title, :string)
@@ -32,6 +34,12 @@ defmodule Pleroma.List do
     |> validate_required([:following])
   end
 
+  def ap_id(%User{nickname: nickname}, list_id) do
+    Pleroma.Web.Endpoint.url() <> "/users/#{nickname}/lists/#{list_id}"
+  end
+
+  def ap_id({nickname, list_id}), do: ap_id(%User{nickname: nickname}, list_id)
+
   def for_user(user, _opts) do
     query =
       from(
@@ -55,6 +63,19 @@ defmodule Pleroma.List do
     Repo.one(query)
   end
 
+  def get_by_ap_id(ap_id) do
+    host = Pleroma.Web.Endpoint.host()
+
+    with %{host: ^host, path: path} <- URI.parse(ap_id),
+         %{"list_id" => list_id, "nickname" => nickname} <-
+           Regex.named_captures(@ap_id_regex, path),
+         %User{} = user <- User.get_cached_by_nickname(nickname) do
+      get(list_id, user)
+    else
+      _ -> nil
+    end
+  end
+
   def get_following(%Pleroma.List{following: following} = _list) do
     q =
       from(
@@ -125,4 +146,15 @@ defmodule Pleroma.List do
     |> follow_changeset(attrs)
     |> Repo.update()
   end
+
+  def memberships(%User{follower_address: follower_address}) do
+    Pleroma.List
+    |> where([l], ^follower_address in l.following)
+    |> join(:inner, [l], u in User, on: l.user_id == u.id)
+    |> select([l, u], {u.nickname, l.id})
+    |> Repo.all()
+    |> Enum.map(&ap_id/1)
+  end
+
+  def memberships(_), do: []
 end