+ def render("context.json", %{activity: activity, activities: activities, user: user}) do
+ %{ancestors: ancestors, descendants: descendants} =
+ activities
+ |> Enum.reverse()
+ |> Enum.group_by(fn %{id: id} -> if id < activity.id, do: :ancestors, else: :descendants end)
+ |> Map.put_new(:ancestors, [])
+ |> Map.put_new(:descendants, [])
+
+ %{
+ ancestors: render("index.json", for: user, activities: ancestors, as: :activity),
+ descendants: render("index.json", for: user, activities: descendants, as: :activity)
+ }
+ end
+