refactor: reduce nesting depth in RoleLive handle_event functions

lib/mv_web/live/role_live/index.ex

@@ -16,15 +16,16 @@ defmodule MvWeb.RoleLive.Index do
   """
   use MvWeb, :live_view
 
-  alias Mv.Authorization
   alias Mv.Accounts
+  alias Mv.Authorization
 
   require Ash.Query
 
   @impl true
   def mount(_params, _session, socket) do
     socket = ensure_user_role_loaded(socket)
-    roles = load_roles()
+    actor = socket.assigns[:current_user]
+    roles = load_roles(actor)
     user_counts = load_user_counts(roles)
 
     {:ok,
@@ -61,46 +62,86 @@ defmodule MvWeb.RoleLive.Index do
 
   @impl true
   def handle_event("delete", %{"id" => id}, socket) do
-    {:ok, role} = Authorization.get_role(id)
-    user_count = get_user_count(role, socket.assigns.user_counts)
+    case Authorization.get_role(id) do
+      {:ok, role} ->
+        handle_delete_role(role, id, socket)
 
-    if user_count > 0 do
-      {:noreply,
-       put_flash(
-         socket,
-         :error,
-         gettext(
-           "Cannot delete role. %{count} user(s) are still assigned to this role. Please assign them to another role first.",
-           count: user_count
-         )
-       )}
-    else
-      case Authorization.destroy_role(role) do
-        :ok ->
-          updated_roles = Enum.reject(socket.assigns.roles, &(&1.id == id))
-          updated_counts = Map.delete(socket.assigns.user_counts, id)
+      {:error, %Ash.Error.Query.NotFound{}} ->
+        {:noreply,
+         put_flash(
+           socket,
+           :error,
+           gettext("Role not found.")
+         )}
 
-          {:noreply,
-           socket
-           |> assign(:roles, updated_roles)
-           |> assign(:user_counts, updated_counts)
-           |> put_flash(:info, gettext("Role deleted successfully"))}
+      {:error, error} ->
+        error_message = format_error(error)
 
-        {:error, error} ->
-          error_message = format_error(error)
-
-          {:noreply,
-           put_flash(
-             socket,
-             :error,
-             gettext("Failed to delete role: %{error}", error: error_message)
-           )}
-      end
+        {:noreply,
+         put_flash(
+           socket,
+           :error,
+           gettext("Failed to delete role: %{error}", error: error_message)
+         )}
     end
   end
 
-  defp load_roles do
-    case Authorization.list_roles() do
+  defp handle_delete_role(role, id, socket) do
+    cond do
+      role.is_system_role ->
+        {:noreply,
+         put_flash(
+           socket,
+           :error,
+           gettext("System roles cannot be deleted.")
+         )}
+
+      recalculate_user_count(role) > 0 ->
+        user_count = recalculate_user_count(role)
+
+        {:noreply,
+         put_flash(
+           socket,
+           :error,
+           gettext(
+             "Cannot delete role. %{count} user(s) are still assigned to this role. Please assign them to another role first.",
+             count: user_count
+           )
+         )}
+
+      true ->
+        perform_role_deletion(role, id, socket)
+    end
+  end
+
+  defp perform_role_deletion(role, id, socket) do
+    case Authorization.destroy_role(role, actor: socket.assigns.current_user) do
+      :ok ->
+        updated_roles = Enum.reject(socket.assigns.roles, &(&1.id == id))
+        updated_counts = Map.delete(socket.assigns.user_counts, id)
+
+        {:noreply,
+         socket
+         |> assign(:roles, updated_roles)
+         |> assign(:user_counts, updated_counts)
+         |> put_flash(:info, gettext("Role deleted successfully."))}
+
+      {:error, error} ->
+        error_message = format_error(error)
+
+        {:noreply,
+         put_flash(
+           socket,
+           :error,
+           gettext("Failed to delete role: %{error}", error: error_message)
+         )}
+    end
+  end
+
+  defp load_roles(actor) do
+    opts = if actor, do: [actor: actor], else: []
+
+    case Authorization.list_roles(opts) do
       {:ok, roles} -> Enum.sort_by(roles, & &1.name)
       {:error, _} -> []
     end
@@ -129,6 +170,14 @@ defmodule MvWeb.RoleLive.Index do
     Map.get(user_counts, role.id, 0)
   end
 
+  # Recalculates user count for a specific role (used before deletion)
+  defp recalculate_user_count(role) do
+    case Ash.count(Accounts.User |> Ash.Query.filter(role_id == ^role.id)) do
+      {:ok, count} -> count
+      _ -> 0
+    end
+  end
+
   defp format_error(%Ash.Error.Invalid{} = error) do
     Enum.map_join(error.errors, ", ", fn e -> e.message end)
   end