#lang racket

(require remote-shell/ssh)

(define cwd
  (make-parameter "~"))

(define host
  (make-parameter #f))

(define user
  (make-parameter #f))

(define commands
  (make-parameter #f))

(define-syntax-rule
  (plan expr ...)
  (parameterize
      ([commands (list)])
    (begin expr ...)))

(define-syntax-rule
  (with-cwd dir expr ...)
  (parameterize
    ([cwd
      (match (substring dir 0 1)
        ["/" dir]
        [_ (format "~a/~a" (cwd) dir)])])
    (begin expr ...)))

(define-syntax-rule
  (with-host remote expr ...)
  (parameterize
    ([host remote])
     (begin expr ...)))

(define-syntax-rule
  (become username expr ...)
  (parameterize
      ([user username])
    (begin expr ...)))

(define (as-user cmd)
  (if
   (user)
     (format "sudo -u ~a sh -c \"~a\""
             (user)
             cmd)
   cmd))

(define (exec cmd)
  (displayln
    (format "Executed on ~a:" (remote-host (host))))
  (ssh (host)
       (as-user
   (string-append
    (format "cd ~a && "
            (cwd))
    cmd))))

(define ((make-cmd cmd)) (exec cmd))

(define ls (make-cmd "ls"))
(define pwd (make-cmd "pwd"))

(provide
  (all-defined-out) remote)