Add login next url parameter for auth redirects

lib/sso_bsn_web/user_auth.ex

@@ -163,11 +163,11 @@ defmodule SsoBsnWeb.UserAuth do
     end
   end
 
-  def on_mount(:redirect_if_user_is_authenticated, _params, session, socket) do
+  def on_mount(:redirect_if_user_is_authenticated, params, session, socket) do
     socket = mount_current_user(socket, session)
 
     if socket.assigns.current_user do
-      {:halt, Phoenix.LiveView.redirect(socket, to: signed_in_path(socket))}
+      {:halt, Phoenix.LiveView.redirect(socket, to: signed_in_path(params["next"]))}
     else
       {:cont, socket}
     end
@@ -224,5 +224,7 @@ defmodule SsoBsnWeb.UserAuth do
 
   defp maybe_store_return_to(conn), do: conn
 
-  defp signed_in_path(_conn), do: ~p"/users/settings"
+  defp signed_in_path(%Plug.Conn{ query_params: %{ "next" => next }}), do: ~p"/redirect?next=#{next}"
+  defp signed_in_path(next) when is_binary(next), do: ~p"/redirect?next=#{next}"
+  defp signed_in_path(_), do: ~p"/users/settings"
 end