#!/bin/sh
exec scsh -lel expect/load.scm -o expect -o srfi-13 -e main -s "$0" "$@"
!#

(define (display-usage)
  (display "Usage: timed-choice.scm timeout query choices...\n")
  (display "Provides a query of the user with a timeout and a default answer.\n"))

(define (raise-too-few-arguments)
  (display "timed-choice.scm: too few arguments\n")
  (display-usage)
  (exit))

(define (main args)
  (if (< (length args) 4)
      (raise-too-few-arguments))
  (let ((timeout (string->number (second args)))
	(query (third args))
	(choices (cdddr args)))
    (let ((default (car choices))
	  (pattern (re-choice (map re-string choices))))
      (display (format #f "~a [~a] " query (string-join choices ", ")))
      (display
       (expect loop ()
	       (option (timeout timeout)
		       (on-timeout default))
	       ((user-task)
		((rx (: bos ,pattern (| "\n" "\r\n"))) (m)
		 (match:substring m))
		((rx (: bos (| "\n" "\r\n"))) ()
		 (string-append default "\n"))
		(else
		 (display (format #f "Please enter one of the choices: ~a.\n"
				  (string-join choices ", ")))
		 (loop)))))
      ;;(newline)
      )))