move thumbnail logic into library context

lib/algora/library.ex

@@ -396,6 +396,21 @@ defmodule Algora.Library do
     end
   end
 
+  def get_thumbnail_url(%Video{} = video) do
+    video.thumbnail_url || "#{AlgoraWeb.Endpoint.url()}/images/og/default.png"
+  end
+
+  def get_thumbnail_url(%User{} = user) do
+    case get_latest_video(user) do
+      # TODO:
+      nil ->
+        "#{AlgoraWeb.Endpoint.url()}/images/og/default.png"
+
+      video ->
+        get_thumbnail_url(video)
+    end
+  end
+
   def reconcile_livestream(%Video{} = video, stream_key) do
     user = Accounts.get_user_by!(stream_key: stream_key)
 

lib/algora_web/controllers/github_controller.ex

@@ -4,43 +4,16 @@ defmodule AlgoraWeb.GithubController do
   alias Algora.{Accounts, Library}
 
   def get_thumbnail(conn, %{"user_id" => user_id}) do
-    with {:ok, user} <- get_user(user_id),
-         {:ok, video} <- get_latest_video(user) do
-      redirect(conn, external: get_thumbnail_url(video))
-    else
-      {:error, :video_not_found} -> redirect(conn, to: ~p"/images/og/default.png")
-      _ -> send_resp(conn, 404, "Not found")
+    case Accounts.get_user_by_provider_id(:github, user_id) do
+      nil -> send_resp(conn, 404, "Not found")
+      user -> redirect(conn, external: Library.get_thumbnail_url(user))
     end
   end
 
   def get_channel(conn, %{"user_id" => user_id}) do
-    case get_user(user_id) do
-      {:ok, user} ->
-        redirect(conn, to: ~p"/#{user.handle}")
-
-      _ ->
-        send_resp(conn, 404, "Not found")
-    end
-  end
-
-  defp get_user(id) do
-    case Accounts.get_user_by_provider_id(:github, id) do
-      nil -> {:error, :user_not_found}
-      user -> {:ok, user}
-    end
-  end
-
-  defp get_latest_video(user) do
-    case Library.get_latest_video(user) do
-      nil -> {:error, :video_not_found}
-      user -> {:ok, user}
-    end
-  end
-
-  defp get_thumbnail_url(video) do
-    case video.thumbnail_url do
-      nil -> ~p"/images/og/default.png"
-      url -> url
+    case Accounts.get_user_by_provider_id(:github, user_id) do
+      nil -> send_resp(conn, 404, "Not found")
+      user -> redirect(conn, to: ~p"/#{user.handle}")
     end
   end
 end