Refactoring of Events context

lib/mobilizon/events/track.ex

@@ -1,15 +1,31 @@
 defmodule Mobilizon.Events.Track do
   @moduledoc """
-  Represents a track for an event (such as a theme) having multiple sessions
+  Represents a track for an event (such as a theme) having multiple sessions.
   """
+
   use Ecto.Schema
+
   import Ecto.Changeset
+
   alias Mobilizon.Events.{Track, Event, Session}
 
+  @type t :: %__MODULE__{
+          color: String.t(),
+          description: String.t(),
+          name: String.t(),
+          event: Event.t(),
+          sessions: [Session.t()]
+        }
+
+  @required_attrs [:name, :description, :color]
+  @optional_attrs [:event_id]
+  @attrs @required_attrs ++ @optional_attrs
+
   schema "tracks" do
     field(:color, :string)
     field(:description, :string)
     field(:name, :string)
+
     belongs_to(:event, Event)
     has_many(:sessions, Session)
 
@@ -17,9 +33,10 @@ defmodule Mobilizon.Events.Track do
   end
 
   @doc false
+  @spec changeset(t, map) :: Ecto.Changeset.t()
   def changeset(%Track{} = track, attrs) do
     track
-    |> cast(attrs, [:name, :description, :color, :event_id])
-    |> validate_required([:name, :description, :color])
+    |> cast(attrs, @attrs)
+    |> validate_required(@required_attrs)
   end
 end