#! emacs --script
;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/script/boxme.el

(require 'cl-lib)

(defun box-me (file &optional xc yc)
  (or xc (setq xc 74))
  (or yc (setq yc 25))
  (when (and (<= 3 xc)
             (<= 3 yc))
    (let* ((yb ?|)
           (xb ?-)
           (cb ?+)
           (xci (- xc 2))
           (tl (format "%c%s%c" cb (make-string xci xb) cb)))
      (with-temp-buffer
        (insert-file-contents file)

        (goto-char (point-max))
        (let ((inhibit-message t))
          (when (re-search-backward "^" (point-min) t)
            (replace-match (char-to-string yb))))

        (goto-char (point-max))
        (cl-loop
         do (goto-char (pos-eol))
         (let ((len (abs (- xc (current-column) 1)))) ; why `abs'?
           (insert (make-string len ?\s)))
         (insert yb)
         until (not (zerop (forward-line -1))))

        (goto-char (point-min))
        (insert tl ?\n)
        (goto-char (point-max))
        (open-line 1)
        (goto-char (point-max))
        (insert tl)

        (message "%s\n" (buffer-substring-no-properties (point-min) (point-max)))
        (kill-emacs)))))

(apply #'box-me (last command-line-args 1))