;;;; prompt.lisp -- a function using readlline to collect text from the user

;; Copyright (C) 2022  Colin Okay

;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU Affero General Public License as
;; published by the Free Software Foundation, either version 3 of the
;; License, or (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU Affero General Public License for more details.

;; You should have received a copy of the GNU Affero General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.


(in-package :oneliners.cli.prompt)

(defun prompt (prompt
               &key
                 (expect (constantly t))
                 retry-text
                 (prefill ""))
  ;; register a prefill hook
  (rl:register-hook
   :pre-input
   (lambda ()
     (rl:insert-text prefill)
     (rl:redisplay)))
  (unwind-protect 
       (loop
         with prompt-text = prompt
         with should-retry-p = t
         while should-retry-p
         for line = (rl:readline :prompt prompt-text)
         when (funcall expect line)
           do (setf should-retry-p nil)
         when retry-text
           do (setf prompt-text retry-text)
         finally (return line))
    ;; unregisters the hook.
    (rl:register-hook :pre-input nil)))