(module utils racket/base

  (require racket/path
           racket/runtime-path
           ffi/unsafe
           setup/dirs
           )
  
  (provide while
           until
           build-lib-path
           get-lib
           do-for
           )

  (define-syntax while
    (syntax-rules ()
      ((_ cond body ...)
       (letrec ((while-f (lambda (last-result)
                           (if cond
                               (let ((last-result (begin
                                                    body
                                                    ...)))
                                 (while-f last-result))
                               last-result))))
         (while-f #f))
       )
      ))

  (define-syntax until
    (syntax-rules ()
      ((_ cond body ...)
       (letrec ((until-f (lambda (last-result)
                           (if cond
                               last-result
                               (let ((last-reult (begin
                                                   body
                                                   ...)))
                                 (until-f last-result))))))
         (until-f #f)))))

  (define-syntax do-for
    (syntax-rules ()
      ((_ (init cond next) body ...)
       (begin
         init
         (letrec ((do-for-f (lamba ()
                                   (if cond
                                       (begin
                                         (begin
                                           body
                                           ...)
                                         next
                                         (do-for-f))))))
           (do-for-f))))))


  (define-runtime-path lib-path "..")

  (define (build-lib-path)
    (let ((os-type (system-type 'os*)))
      (if (eq? os-type 'windows)
          (build-path lib-path "lib" "dll")
          (let* ((arch (symbol->string (system-type 'arch)))
                 (subdir (string-append (symbol->string os-type) "-" arch)))
            (let ((path (build-path lib-path "lib" subdir)))
              path)))))

  (define (get-lib* libs-to-try orig-libs versions)
    (if (null? libs-to-try)
        (error (format "Cannot find library, tried ~a" orig-libs)) 
        (ffi-lib (car libs-to-try) versions
                 #:get-lib-dirs (λ () (cons (build-lib-path) (get-lib-search-dirs)))
                 #:fail (λ () (get-lib* (cdr libs-to-try) orig-libs versions))
                 )))

  (define (get-lib libs-to-try versions)
    (get-lib* libs-to-try libs-to-try versions))
  
  ) ; end of module