(use extras http-client progress-indicators filepath)

(define *s* (make-string 2048))

(define o (open-output-file "/tmp/a.mp3"))

(define (read/write filename length outport #!optional (bs (* 1024 2)))
  (let ((bar (make-progress-bar
               frame:
               (string-append filename ": [~a~a~a~a|~a]")
               width:
               40
               max:
               length)))
    (let loop ((size length))
      (let* ((bytes (min bs size)))
        (if (zero? size)
          #t
          (let ((input (read-string! bytes *s*)))
            (if (> input 0)
              (begin
                (write-string *s* bytes outport)
                (advance-progress-bar! bar bytes))
              (when (> bytes 0)
                    (error "Missing ~a from input" (pretty-filesize bytes))))
            (loop (- size bytes))))))
   (finish-progress-bar! bar)))

(define (filename-from-url u) (filepath:take-file-name u))
(define (get-file-port file) (file-open file (+ open/wronly open/creat)))

(define (download-enclosure url length dest catcher)
  (let* ((filename (filename-from-url url))
         (target-location (string-append dest "/" filename))
         (temp-file (string-append target-location ".part"))
         (fd (get-file-port temp-file))
         (outport (open-output-file* fd)))
    (if (equal? catcher 'curl)
      (unless
        (zero? (system
                 (string-intersperse (list "curl" "-L" "-o" temp-file url))))
        (printf "\tStill cannot download ~a~%" url)
        (file-close fd)
        (delete-file temp-file))
      (condition-case
        (with-input-from-request
          url
          #f
          (if (zero? length)
            (begin
              (print "Downloading " filename)
              (print "This podcast has no valid length, using simple copy-port w/o output!")
              (lambda () (copy-port (current-input-port) outport)))
            (lambda () (read/write filename length outport))))
        (e (exn net i/o)
           (printf
             "~%\tError while downloading ~a to ~a:~%\t~a~%"
             url
             filename
             ((condition-property-accessor 'exn 'message) e))
           (printf "\tRetrying with curl...~%")
           (unless
             (zero? (system
                      (string-intersperse
                        (list "curl" "-L" "-o" temp-file url))))
             (printf "\tStill cannot download ~a~%" url)
             (file-close fd)
             (delete-file temp-file)))
        (e (exn http unsupported-uri-scheme)
           (print "Cannot download "
                  url
                  " with http-client, shelling out to curl")
           (unless
             (zero? (system
                      (string-intersperse
                        (list "curl" "-L" "-o" temp-file url))))
             (printf
               "\tUrl scheme ~a is not supported. Cannot download ~a~%"
               ((condition-property-accessor
                  'unsupported-uri-scheme
                  'uri-scheme)
                e)
               url)
             (file-close fd)
             (delete-file temp-file)))))
    (when (file-exists? temp-file)
          (print " done.")
          (rename-file temp-file target-location))))

(download-enclosure  "http://localhost:8888/alternativlos-17.mp3" 89885440 "/tmp" #f)