#lang racket/base
;; Untyped struct definitions required to interoperate with marketplace's struct-map
;; See also Racket PR 13593.

(require marketplace/struct-map)

(provide (struct-out domain))

;; (These utilities need to be defined ahead of the domain struct
;; definition.)
(define (domain=? a b recursive-equal?)
  (recursive-equal? (domain-downcased-labels a)
		    (domain-downcased-labels b)))

(define (domain-hash-1/2 d recursive-hash)
  (recursive-hash (domain-downcased-labels d)))

(struct domain (labels downcased-labels)
	#:transparent
	#:property prop:equal+hash (list domain=? domain-hash-1/2 domain-hash-1/2)
	#:property prop:struct-map (lambda (f seed x)
				     (let-values (((labels seed) (f (domain-labels x) seed)))
				       (values (make-domain labels) seed))))

;; ListOf<Bytes> -> ListOf<Bytes>
;; Converts the 7-bit ASCII bytes in the argument to lower-case
;; equivalents. Used to normalize case for domain-name comparisons.
(define (downcase-labels labels)
  (for/list ([label labels])
    (define b (make-bytes (bytes-length label)))
    (for ([i (bytes-length label)])
      (define v (bytes-ref label i))
      (bytes-set! b i (if (<= 65 v 90) (+ 32 v) v)))
    b))

;; ListOf<Bytes> -> DomainName
;; Replacement constructor for domain structs. Automatically downcases
;; labels appropriately.
(define (make-domain labels)
  (domain labels (downcase-labels labels)))