(use-modules ((gnu packages base) #:select (tar))
  ((gnu packages bash) #:select (bash-minimal))
  ((gnu packages compression) #:select (lzip))
  ((gnu packages python) #:select (python))
  (guix)
  (guix build-system trivial))




(package
  (name "blog")
  (version "3")
  (source
    (origin
      (method url-fetch)
      (uri (string-append "file:///home/phf/programs/blog/releases/release_" version ".tar.lz"))
      (sha256
        (base32
          "1y819b53ksyas6asldysr0r8p73n5i8ipbpmbgjrfx8qz8cy2zsx"))))
  (build-system trivial-build-system)
  (arguments
    `(#:modules ((guix build utils))
       #:builder
       (begin

         (use-modules (guix build utils))


         (newline)
         (display "Start of build expression execution")
         (newline)
         (newline)



         (display "Show inputs")
         (newline)
         ((lambda (name value)
            (display (string-join (list name "=" (format #f "~a" value) "\n"))))
           "  %build-inputs" %build-inputs)



         (newline)
         (display "Show outputs")
         (newline)
         ((lambda (name value)
            (display (string-join (list name "=" (format #f "~a" value) "\n"))))
           "  %outputs" %outputs)



         (newline)
         (display "Unpack source")
         (newline)
         (let ((source (assoc-ref %build-inputs "source"))
                (tar (assoc-ref %build-inputs "tar"))
                (lzip (assoc-ref %build-inputs "lzip")))

           (setenv "PATH" (string-append
                            tar "/bin"
                            ":"
                            lzip "/bin"))

           (invoke "tar" "--lzip" "-xvf" source))


         (newline)
         (display "Reference interpreters available in the build")
         (newline)
         (let ((bash (assoc-ref %build-inputs "bash"))
                (python (assoc-ref %build-inputs "python")))
           (substitute* "blog/bin/program"
             (("/usr/bin/env bash") (string-append bash "/bin/bash"))
             (("python3") (string-append python "/bin/python3"))))



         (newline)
         (display "Make executable available to the host system")
         (newline)
         (let ((out (assoc-ref %outputs "out")))
           (chmod "blog/bin/program" #o775)
           (copy-recursively "blog" out))
         (newline)



         (newline)
         (display "End of build expression execution")
         (newline)
         (newline)
         )))

  (inputs
    `(("bash" ,bash-minimal)
       ("python" ,python)))

  (native-inputs
    `(("lzip" ,lzip)
       ("tar" ,tar)))

  (synopsis #f)
  (description #f)
  (home-page #f)
  (license #f))