;; 
;; %%HEADER%%
;; 

;; this file implements migrations with a timestamped versioning
;; scheme

(define (configure-timestamped-migrations)
  (nomads:versioner (lambda (max-version)
                      (inexact->exact (current-seconds))))

  (nomads:filename-partitioner      
   (lambda (filename)
     (let ((parts (string-split filename "-")))
       (cond
        ((null? parts) (cons #f ""))
        ((string->number (car parts))
         => (lambda (num)
              (cons (number->string (inexact->exact num)) (string-join (cdr parts) "-"))))
        (else (cons #f filename))))))

  (nomads:filename-joiner           
   (lambda (version file)
     (sprintf "~A-~A" version file)))

  (nomads:version? number?)

  (define (->number what)
    (inexact->exact (if (string? what) (string->number what) what)))

  (nomads:version-less?
   (lambda (l r)
     (< (->number l) (->number r))))

  (nomads:version-equal?
   (lambda (l r)
     (equal? (->number l) (->number r)))))