handle already following better, cache actor query

lib/vonbraun/control.ex

@@ -59,7 +59,7 @@ defmodule Vonbraun.Control do
           {:error, {:post, error}}
       end
     else
-      {:pending, {:ok, %{:blocks_me => nil, :following_state => "accepted"}}} ->
+      {:pending, {:error, :already_following}} ->
         Logger.info("I think you already follow them.")
         :ok
 

lib/vonbraun/ecto/schema/actor.ex

@@ -104,6 +104,8 @@ defmodule Vonbraun.Ecto.Schema.Actor do
     with {:actor,
           {:ok, actor = %{:blocked => blocked?, :following_state => existing_following_state}}} <-
            {:actor, maybe_insert(id)} do
+      already_following? = existing_following_state == "accepted" && new_state == "pending"
+
       valid_set_pending? = existing_following_state == nil && new_state == "pending"
 
       valid_set_response? =
@@ -120,6 +122,9 @@ defmodule Vonbraun.Ecto.Schema.Actor do
           changeset(actor, %{following_state: new_state, following_ts: DateTime.now!("Etc/UTC")})
           |> Repo.update()
 
+        already_following? ->
+          {:error, :already_following}
+
         true ->
           {:error, :invalid_state}
       end