;download-xml-forecast.scm: download current xml forecast for SLC from noaa site,
;and save it to a file named according to current date.

(require (lib "url.ss" "net"))

(define noaa-string "http://www1.wrh.noaa.gov/cgi-bin/dwf?outFormat=xml&duration=168hr&interval=12&citylist=Select+City%2C%2Cnone&latitude=&longitude=&ZOOMLEVEL=8&XSTART=220&YSTART=368&XC=246&YC=401&X=246&Y=401&siteID=SLC&click.x=206&click.y=248")
   
(define url:noaa (string->url noaa-string))
(define i (get-pure-port url:noaa))

; date->filename : date -> string
; make "{year}{month}{day}" string for output filename
(define (date->filename d)
  (let ((number->paddedstring (lambda(n)
        (cond
          [(< n 10) (string-append "0" (number->string n))]
          [else (number->string n)]))))

        (apply string-append (map number->paddedstring 
                                  (list (date-year d) (date-month d) (date-day d))))))

(define o (open-output-file (string-append
                             (date->filename (seconds->date (current-seconds)))
                             ".xml")))

(define (copy-files input-port output-port)
  (let ((c (read-char input-port)))
  (cond
    [(not (eof-object? c)) 
     (write-char c output-port)
     (copy-files input-port output-port)])))

(copy-files i o)

(close-output-port o)