(ns blog.rss
  (:require
   [blog.gemtext :as gemtext]
   [blog.time :as time]
   [clojure.data.xml :refer :all]
   [commonmark-hiccup.core :refer [markdown->hiccup default-config]]
   [hiccup.core :as hiccup]))

(defn item [linkfn {:keys [title date slug tags short body gemtext?]}]
  (let [link (linkfn slug)]
    [:item
     [:title title]
     (when body
       [:description
        [:-cdata
         (hiccup/html
          (if gemtext?
            (-> body gemtext/parse gemtext/to-hiccup)
            (markdown->hiccup default-config body)))]])
     [:guid link]
     [:link link]
     [:pubDate (time/fmt-rfc-2822 date)]]))

(defn feed [linkfn posts]
  (indent-str
   (sexp-as-element
    [:rss {:version "2.0" :xmlns:atom "http://www.w3.org/2005/Atom"}
     [:channel
      [:title "yumh"]
      [:description "Writing about things, sometimes"]
      [:link "https://www.omarpolo.com"]
      ;; fails to validate?
      ;; [:atom:link {:href "https://www.omarpolo.com/rss.xml" :ref "self" :type "application/rss+xml"} nil]
      (map (partial item linkfn)
           posts)]])))