(define-module (ldp path)
  #:use-module (oop goops)
  #:use-module (web uri))

(define-class <path> ()
  (components-rev #:init-keyword #:components-rev #:getter path-components-rev))

(export <path>)

(define-public (is-root? x)
  (equal? (path-components-rev x) '()))

(define-public (path->filename x)
  (if (is-root? x)
      "."
      (string-append
       "./"
       (encode-and-join-uri-path
	(map (lambda (x)
	       (string-append "r_" x))
	     (reverse (path-components-rev x)))))))

(define-public (path->uri x)
  (let* ((components (reverse (path-components-rev x)))
	 (relative-to-root (encode-and-join-uri-path components))
	 (path (string-append "/" relative-to-root)))
    (build-uri-reference #:path path)))

(define-public (path->string x)
  (uri-path (path->uri x)))

(define-public (uri->path x)
  (make <path>
    #:components-rev
    (reverse (split-and-decode-uri-path (uri-path x)))))

(define-public (string->path x)
  (uri->path (build-uri-reference #:path x)))

(define-public (path? x)
  (is-a? x <path>))

(define-public (the-path x)
  (unless (path? x)
    (scm-error 'wrong-type-arg
	       "the-path"
	       "Expected a path from (ldp path)."
	       '()
	       (list x)))
  x)

(define-public (path-parent x)
  (make <path> #:components-rev (cdr (path-components-rev x))))

(define-public (path-cons container slug)
  (make <path>
    #:components-rev
    (cons slug (path-components-rev container))))

(define-public (path-slug x)
  (car (path-components-rev x)))

(define-public (path-equal? x y)
  (equal? (path-components-rev x) (path-components-rev y)))