(define-module (config)
  :export (feeds))

(use-modules
 (sxml xpath)
 (ice-9 regex)

 (feed-handler)

 ((datetime) :select (datetime datetime->string)))


(define (parse-month str)
  "Get month number from (a shortened) monthname.
Returns -1 on failure"
  (let loop ((i 1)
             (months
              (list "january" "february" "march" "april" "may" "june" "july"
                    "august" "september" "october" "november" "december")))


    (if (null? months)
        -1
        (let ((len (min (string-length (car months))
                        (string-length str))))
          (if (string=?
               (string-take (string-downcase str) len)
               (string-take (car months) len))
              i
              (loop (1+ i) (cdr months)))))))


(define (parse-date str)
  (and=> (string-match "([a-zA-Z]*)\\. ([0-9]+), ([0-9]+), ([0-9]+):([0-9]+) ([ap])\\.m\\." str)
         (lambda (m)
           (let ((month (match:substring m 1))
                 (day (string->number (match:substring m 2)))
                 (year (string->number (match:substring m 3)))
                 (hour (string->number (match:substring m 4)))
                 (minute (string->number (match:substring m 5)))
                 (am-pm (match:substring m 6)))
             (datetime #:year year
                       #:month (parse-month month)
                       #:day day
                       #:hour (+ hour (if (string=? am-pm "p") 12 0))
                       #:minute minute)))))

(define feeds
  (list
   (make-feed
    "https://lwn.net/headlines/Features"
    `((rss:item
       . ,(lambda (key . children)
            (define tag (cons key children))
            (call-with-values (lambda () (apply values ((sxpath '(rss:title *text*)) tag)))
              (case-lambda (() tag)
                           ((title . _)
                            (if (string-match "^\\[\\$\\]" title)
                                '() tag))))))))

   (make-feed
    "https://swordscomic.com/comic/feed/"
    `((rss:pubDate
       . ,(lambda (key . children)
            (cond ((parse-date (car children))
                   => (lambda (dt)
                        (list key (datetime->string dt "~Y-~m-~dT~H:~M:~S"))))
                  (else (cons key children)))))

      (rss:description
       . ,(lambda (key . children)
            (cons key
                  ;; Each entry has a <style/> tag at the
                  ;; beggining, which brakes the short preview on
                  ;; NetNewsWire. This removes it
                  (cond ((string-match "</style>" (car children))
                         => (lambda (m)
                              (list (string-drop (car children) (match:end m)))))
                        (else children)))))
      ))
   ))