(setq lexical-binding t)

(setq ns-use-native-fullscreen nil)

(defun ns-toggle-frame-fullscreen ()
  "Perform non-native fullscreen neatly on macOS."
  (interactive)
  (if (frame-parameter nil 'ns-use-native-fullscreen)
      (toggle-frame-fullscreen)
    (let ((fullscreen (frame-parameter nil 'windowed-params)))
      (cond
       (fullscreen
        (let ((auto-hide-menu-bar (cdr (assq 'ns-auto-hide-menu-bar (frame-parameter nil 'windowed-params))))
              (windowed-params (cdr (frame-parameter nil 'windowed-params))))
          (set-frame-parameter nil 'windowed-params nil)
          (modify-frame-parameters nil windowed-params)
          (setq ns-auto-hide-menu-bar auto-hide-menu-bar)))
       (t
	(let ((old-params
	       (list (cons 'ns-auto-hide-menu-bar ns-auto-hide-menu-bar)
		     (assq 'undecorated (frame-parameters))
		     ;(assq 'fullscreen (frame-parameters))
		     (assq 'width (frame-parameters))
		     (assq 'height (frame-parameters))
		     (assq 'top (frame-parameters))
		     (assq 'left (frame-parameters)))))
	  (setq ns-auto-hide-menu-bar t)
	  (modify-frame-parameters nil `((undecorated . t)
                                         (top . 0)
                                         (left . 0)
                                         (windowed-params . ,old-params)))
          (set-frame-size nil (display-pixel-width) (display-pixel-height) t)))))))