Refactoring of Actors context

lib/mobilizon/actors/follower.ex

@@ -1,52 +1,63 @@
 defmodule Mobilizon.Actors.Follower do
   @moduledoc """
-  Represents the following of an actor to another actor
+  Represents the following of an actor to another actor.
   """
+
   use Ecto.Schema
+
   import Ecto.Changeset
-  alias Mobilizon.Actors.Follower
+
   alias Mobilizon.Actors.Actor
 
-  @primary_key {:id, :binary_id, autogenerate: true}
+  @type t :: %__MODULE__{
+          approved: boolean,
+          url: String.t(),
+          target_actor: Actor.t(),
+          actor: Actor.t()
+        }
 
+  @required_attrs [:url, :approved, :target_actor_id, :actor_id]
+  @attrs @required_attrs
+
+  @primary_key {:id, :binary_id, autogenerate: true}
   schema "followers" do
     field(:approved, :boolean, default: false)
     field(:url, :string)
+
     belongs_to(:target_actor, Actor)
     belongs_to(:actor, Actor)
   end
 
   @doc false
-  def changeset(%Follower{} = member, attrs) do
-    member
-    |> cast(attrs, [:url, :approved, :target_actor_id, :actor_id])
-    |> generate_url()
-    |> validate_required([:url, :approved, :target_actor_id, :actor_id])
-    |> unique_constraint(:target_actor_id, name: :followers_actor_target_actor_unique_index)
+  @spec changeset(t | Ecto.Changeset.t(), map) :: Ecto.Changeset.t()
+  def changeset(follower, attrs) do
+    follower
+    |> cast(attrs, @attrs)
+    |> ensure_url()
+    |> validate_required(@required_attrs)
+    |> unique_constraint(:target_actor_id,
+      name: :followers_actor_target_actor_unique_index
+    )
   end
 
   # If there's a blank URL that's because we're doing the first insert
-  defp generate_url(%Ecto.Changeset{data: %Follower{url: nil}} = changeset) do
+  @spec ensure_url(Ecto.Changeset.t()) :: Ecto.Changeset.t()
+  defp ensure_url(%Ecto.Changeset{data: %__MODULE__{url: nil}} = changeset) do
     case fetch_change(changeset, :url) do
       {:ok, _url} -> changeset
-      :error -> do_generate_url(changeset)
+      :error -> generate_url(changeset)
     end
   end
 
   # Most time just go with the given URL
-  defp generate_url(%Ecto.Changeset{} = changeset), do: changeset
+  defp ensure_url(%Ecto.Changeset{} = changeset), do: changeset
 
-  defp do_generate_url(%Ecto.Changeset{} = changeset) do
+  @spec generate_url(Ecto.Changeset.t()) :: Ecto.Changeset.t()
+  defp generate_url(%Ecto.Changeset{} = changeset) do
     uuid = Ecto.UUID.generate()
 
     changeset
-    |> put_change(
-      :url,
-      "#{MobilizonWeb.Endpoint.url()}/follow/#{uuid}"
-    )
-    |> put_change(
-      :id,
-      uuid
-    )
+    |> put_change(:id, uuid)
+    |> put_change(:url, "#{MobilizonWeb.Endpoint.url()}/follow/#{uuid}")
   end
 end