(module
 ugarit-mime
 (extension-from-filename
  mimetype->extension
  extension->mimetype)

 (import scheme)
 (import chicken)
 (use srfi-13)
 (use srfi-69)

(define *mime-types*
  '(
    ;; Alphabetical order of (primary) extension
    (".avi" . "video/x-msvideo")
    (".c" . "text/x-c")
    (".class" . "application/java-vm")
    (".cpp" . "text/x-cpp")
    (".doc" . "application/msword")
    (".flag" . "audio/x-flac")
    (".gif" . "image/gif")
    (".h" . "text/x-c-header")
    ((".jpeg" ".jpg") . "image/jpeg")
    (".jar" . "application/java-archive")
    (".js" . "application/javascript")
    (".json" . "application/json")
    (".mng" . "video/x-mng")
    (".mov" . "video/quicktime")
    (".mp3" . "audio/mpeg")
    (".mp4" . "audio/mp4")
    ((".mpeg" ".mpg") . "video/mpeg")
    (".ogg" . "audio/ogg")
    (".ogv" . "video/ogg")
    (".pdf" . "application/pdf")
    (".pgp" . "application/pgp-encrypted")
    (".png" . "image/png")
    (".ps" . "application/postscript")
    (".rdf" . "application/rdf+xml")
    (".rtf" . "application/rtf")
    (".scm" . "text/x-scheme")
    (".sexpr" . "text/x-s-expression")
    (".sig" . "application/pgp-signature")
    (".svg" . "image/svg+xml")
    (".txt" . "text/plain")
    (".xml" . "text/xml")
))

(define *extension-to-mimetype*
  ;; Expand multiple extensions to multiple entries
  (let ((ht (make-hash-table)))
    (for-each
     (lambda (e)
       (let ((ext (car e))
             (mt (cdr e)))
         (if (list? ext)
             (for-each
              (lambda (ext)
                (hash-table-set! ht ext mt))
              ext)
             (hash-table-set! ht ext mt))))
     *mime-types*)
    ht))

(define *mimetype-to-extension*
  (alist->hash-table
   (map
    (lambda (aref)
      (cons
       (cdr aref)
       (if (list? (car aref))
           (car (car aref)) ; Prefer first
           (car aref))))
    *mime-types*)))

(define *unknown-mimetype* "application/octet-stream")

(define (extension-from-filename fn)
  (let ((dot-pos (string-index fn #\.)))
    (if dot-pos
        (substring/shared fn dot-pos)
        "")))

(define (mimetype->extension mt)
  (if (string=? mt "inode/directory")
      ""
      (if (hash-table-exists? *mimetype-to-extension* mt)
          (hash-table-ref *mimetype-to-extension* mt)
          (if (string-prefix? "text/" mt)
              ".txt"
              ""))))

(define (extension->mimetype ext)
  (if (string=? ext "")
      *unknown-mimetype*
      (if (hash-table-exists? *extension-to-mimetype* ext)
          (hash-table-ref *extension-to-mimetype* ext)
          *unknown-mimetype*)))

)