#lang racket/base

(require (prefix-in log: (planet synx/log)))

(define (wait-for-pipes pipes)
   (for
    ((pipe pipes))
    (let ((input (car pipe)) (pid (cdr pipe)))
      (close-output-port input)
      (subprocess-wait pid))))

(define-syntax pipe-between
   (syntax-rules (input: pipes:)
     ((_ (process args ...) rest ...)
      (pipe-between
       pipes:
       null
       input:
       (current-output-port)
       (process args ...)
       rest
       ...))
     ((_ pipes: pipes input: input (process args ...))
      (let-values (((pid stdout stdin error)
                    (subprocess
                     input
                     (current-input-port)
                     (current-error-port)
                     (find-executable-path process)
                     args
                     ...)))
        (subprocess-wait pid)
        (wait-for-pipes pipes)))
     ((_ pipes: pipes input: input (process args ...) rest ...)
      (let-values (((pid nothin stdin error)
                    (subprocess
                     (or input (current-output-port))
                     #f
                     (current-error-port)
                     (find-executable-path process)
                     args
                     ...)))
        (pipe-between
         pipes:
         (cons (cons stdin pid) pipes)
         input:
         stdin
         rest
         ...)))))

(define (main)
   (call-with-output-file
    "debug.log"
    #:exists
    'replace
    (λ (output)
      (parameterize
       ((current-error-port output) (log:port (current-output-port)))
       (with-output-to-file
        "etc.cpio.gz"
        #:exists
        'replace
        (λ ()
          (pipe-between ("gzip") ("cpio" "-o") ("find" "/etc" "-xdev"))))))))

(provide main pipe-between)