#! /usr/bin/guile \
-e main -s
!#

(use-modules (sxml simple))

(define site-url "https://shittyweb.org")

;; Generate description from article file
(define (get-description file)
  (call-with-input-file file
    (lambda (fp)
      (letrec ((read-characters
                (lambda (fp)
                  (let ((character (read-char fp)))
                    (unless (eof-object? character)
                      (display character)
                      (read-characters fp))))))
        (display "<![CDATA[\n")
        (read-characters fp)
        (display "]]>\n")))))


(define (format-article-filename file)
  (let ((file-length (string-length file)))
    (string-append (substring file
                              0
                              (- file-length 4))
                   ".xhtml")))

;; Generate rss item
(define (make-item article)
  (let ((title (cadr (list-ref article 0)))
        (pub-date (cadr (list-ref article 4)))
        (file (cadr (list-ref article 6))))
    (format #t "\n    <item>\n\
        <title>~a</title>\n\
        <link>~a/blog/~a</link>\n\
        <pubDate>~a</pubDate>\n\
        <description>\n"
            title site-url (format-article-filename file) pub-date)
    (get-description file)
    (display "        </description>\n")
    (display "    </item>\n")))
    
;; Generate rss feed
(define (generate-feed)
  ;; Display the rss header
  (format #t "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n\
<rss version=\"2.0\">\n\
  <channel>\n\
    <title>Nathan's shitty blog</title>\n\
    <description>The coffee powered blog of chaos</description>\n\
    <link>~a/blog</link>\n\
    <image>\n\
      <url>~a/images/icon.png</url>\n\
      <title>Nathan's shitty blog</title>\n\
      <link>~a/blog</link>\n\
    </image>\n" site-url site-url site-url)

  (call-with-input-file "articles.xml"
    (lambda (fp)
      (let ((articles (xml->sxml fp)))
        (for-each (lambda (article)
                    (if (list? article)
                      (make-item (cddr article))))
                  (cdr (cadr articles))))))

  (display "  </channel>\n")
  (display "</rss>\n"))

(define (main args)
  (generate-feed))