Flag to replace WP login with WPDM Pro Login page

I’m developing a theme, and I always want the user to land on the custom login page if it is defined…so I want to redirect the user to the login page from wp-login.php.

Here is the code that I’m added for my purposes…your mileage may vary (I didn’t include the UI toggle, obviously…)

		/**
		 * Redirect the user to the Download Manager's login page instead of wp-login.php.
		 */
		add_action( 'login_form_login', array( $this, 'redirect_to_custom_login' ) );
		function redirect_to_custom_login() {
			if ( $_SERVER['REQUEST_METHOD'] == 'GET' ) {         //Only when the form is being called, not posted
				if ( is_user_logged_in() ) {
					wp_redirect( self::$dashboard_url ); 
				} else {
					wp_redirect( self::$login_url );
				}
			}
		}
		/**
		 * Set a static constant for the login URL so I don't have to do it on every single tpl page...
		 */
		function set_login_url() {
			$login_id = get_option('__wpdm_login_url');
			if( $login_id > 0)
				$login_url = get_permalink( $login_id );
			else $login_url = wp_login_url();
			
			$redirect_to = ( isset($_GET['redirect']) && 'referer' == $_GET['redirect'] ) ? $_SESSION['HTTP_REFERER'] : null;
			$redirect_to = isset( $_REQUEST['redirect_to'] ) ? $_REQUEST['redirect_to'] : $redirect_to;
			if ( !empty( $redirect_to ) ) {
				$login_url = add_query_arg( 'redirect_to', $redirect_to, $login_url );
			}
			self::$login_url = $login_url;
		}