#!/usr/bin/env mzscheme
#lang scheme/base

(require scheme/pretty
         scheme/system)

;; ssh invocation to make sure no default identities are tried from
;; the agent connection.

;;  ssh -i <identityfile> -o "IdentitiesOnly yes" <host> <command>

;; ssh will concatenate all arguments into a single string and pass it
;; to the shell. in case shell is redirected, this command will end up
;; in SSH_ORIGINAL_COMMAND


(define (parse x)
  (read (open-input-string x)))

(define (with-log file thunk)
  (parameterize
      ((current-output-port 
        (open-output-file file #:exists 'append)))
    (let ((retval
           (thunk)))
      (close-output-port
       (current-output-port))
      retval)))
  
(define (l x)
  (with-log
   "/tmp/dispatch.log"
   (lambda () (printf "~s\n" x) x)))


(define command
  (l
   (or (getenv "SSH_ORIGINAL_COMMAND")
       (error 'no-ssh-command))))


;; run shell
(system command)