function after_login_redirect_to_destination(){
if (!is_user_logged_in() && !is_home()){
$redirect = home_url() . '/wp-login.php?redirect_to=' . urlencode( $_SERVER['REQUEST_URI'] );
wp_redirect( $redirect );
exit;
}
}
add_action( 'wp', 'after_login_redirect_to_destination', 3 );
the above sample code works and redirect to the login page and after successfull login it will redirect to home page. Whenever a non-logged in user try to access the home page, it will redirect to the login page and after successfull login then it will redirect back to destination page. Here the destination page(home page in this case) . You can modify the code above to your redirect to your custom login page and after success it will then redirect to the current page you were
Hope that helps!