#lang racket/base
(require "racket.rkt")
(require "number.rkt" "utils.rkt")
(provide (all-defined-out))

#|
approximates
https://github.com/mbutterick/restructure/blob/master/src/Buffer.coffee
|#

#|
A Buffer is a container object for any data object that supports random access
A Node Buffer object is basically a byte string.
First argument must be a string, Buffer, ArrayBuffer, Array, or array-like object.
A Restructure RBuffer object is separate.
|#

(define (+Buffer xs [type #f])
  ((if (string? xs)
       string->bytes/utf-8
       list->bytes) xs))

(define-subclass xenomorph-base% (RBuffer [len #xffff])
  
  (define/augment (decode port [parent #f])
    (define decoded-len (resolve-length len port parent))
    (read-bytes decoded-len port))

  (define/augment (size [val #f] [parent #f])
    (when val (unless (bytes? val)
                (raise-argument-error 'Buffer:size "bytes" val)))
    (if val
        (bytes-length val)
        (resolve-length len val parent)))

  (define/augment (encode port buf [parent #f])
    (unless (bytes? buf)
      (raise-argument-error 'Buffer:encode "bytes" buf))
    (define op (or port (open-output-bytes)))
    (when (NumberT? len)
      (send len encode op (length buf)))
    (write-bytes buf op)
    (unless port (get-output-bytes op))))

(define-subclass RBuffer (BufferT))


#;(test-module
   (require "stream.rkt")
   (define stream (+DecodeStream #"\2BCDEF"))
   (define S (+String uint8 'utf8))
   (check-equal? (send S decode stream) "BC")
   (define os (+EncodeStream))
   (send S encode os "Mike")
   (check-equal? (send os dump) #"\4Mike")
   (check-equal? (send (+String) size "foobar") 6))