;;;; main.lisp -- oneliners.cli entrypoint

(defpackage oneliners.cli
  (:use :cl))
(in-package :oneliners.cli)

;;; CLI OPTIONS

;; (opts:define-opts
;;   (:name ))


;;; UTILITIES

(defun parent-process-name ()
  "Prints the name of the parent process of the current process."
  (let ((ppidfile (format nil "/proc/~a/status" (osicat-posix:getppid))))
    (first (last 
            (ppcre:split "\\s" 
                         (with-open-file (input ppidfile)
                           (read-line input)))))))

(defmacro wait-until ((&key (timeout 1) (poll-every 0.01)) &body check)
  "Run CHECK every POLL-EVERY seconds until either TIMEOUT seconds
have passed or CHECK returns non-nil."
  (let ((clockvar (gensym))
        (var (gensym)))
    `(loop
       for ,clockvar from 0 by ,poll-every to ,timeout
       for ,var = (progn ,@check)
       when ,var
         return ,var
       do (sleep ,poll-every))))

(defun run-with-shell
    (command
     &key
       (shell-name (parent-process-name))
       (await-output-p 0.8)
       (output-stream *standard-output*))
  "run COMMAND, a string, in a fresh shell environment, initialized
with SHELL-NAME. The output from the command read line by line and is
printed to OUTPUT-STREAM. "
  (let ((shell
          (uiop:launch-program shell-name :input :stream :output :stream)))
    (symbol-macrolet ((shell-input (uiop:process-info-input shell))
                      (shell-output (uiop:process-info-output shell)))
      (write-line command shell-input)
      (finish-output shell-input)
      (when await-output-p
        (wait-until (:timeout await-output-p :poll-every 0.005)
          (listen shell-output))
        (loop while (listen shell-output)
              do (princ (read-line shell-output) output-stream)
                 (terpri output-stream))))))