;;; publish.el --- Publishing configuration for ryuslash.org  -*- lexical-binding: t; -*-

;; Copyright (C) 2020  Tom Willemse

;; Author: Tom Willemse <tom@ryuslash.org>
;; Keywords:

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;

;;; Code:

(require 'ox-publish)
(require 'ox-rss)
(require 'subr-x)

(defun publish-calculate-reading-time (buffer)
  "Calculate the amount of minutes it would take to read the contents of BUFFER."
  (with-current-buffer buffer
    (max 1 (/ (count-words (point-min) (point-max)) 228))))

(defun publish-format-reading-time (time)
  "Return a string describing TIME."
  (format "%d minute%s"
          time
          (if (= time 1) "" "s")))

(defun publish-org-sitemap (title list)
  "Create a site map file. TITLE is used as the title, LIST is turned into a subtree."
  (concat "#+TITLE: " title "\n"
          "#+OPTIONS: toc:nil num:nil\n\n"
          ;; (message "Lets see here: %S" list)
          (org-list-to-subtree list)))

(defun publish-org-sitemap-format-entry (entry style project)
  "Format ENTRY as a healine.
STYLE is ignored and PROJECT is passed on directly to related functions."
  (unless (directory-name-p entry)
    (format "%s\n  :PROPERTIES:\n  :ID: %s\n  :RSS_PERMALINK: %s\n  :PUBDATE: %s\n  :END:\n  %s\n  Published on: %s\n\n  [[file:%s][Read More]] (%s)"
            (org-publish-find-title entry project)
            entry
            (concat (string-remove-suffix ".org" entry) ".html")
            (format-time-string
             (cdr org-time-stamp-formats)
             (org-publish-find-date entry project))

            (with-temp-buffer
              (insert-file-contents (concat (plist-get (cdr project) :base-directory) "/" entry))
              (goto-char (point-min))
              (let ((current-element (org-element-at-point)))
                (while (not (equal (org-element-type current-element) 'paragraph))
                  (org-forward-element)
                  (setq current-element (org-element-at-point)))
                (buffer-substring-no-properties
                 (plist-get (cadr current-element) :contents-begin)
                 (plist-get (cadr current-element) :contents-end))))
            (format-time-string
             (cdr org-time-stamp-formats)
             (org-publish-find-date entry project))
            entry
            (with-temp-buffer
              (insert-file-contents (concat (plist-get (cdr project) :base-directory) "/" entry))
              (publish-format-reading-time
               (publish-calculate-reading-time (current-buffer)))))))

(setq org-rss-use-entry-url-as-guid t)

(setq org-export-exclude-tags '("noexport" "draft"))

(setq org-publish-project-alist
      '(("posts"
         :base-directory "posts/"
         :base-extension "org"
         :publishing-directory "public/"
         :recursive t
         :publishing-function org-html-publish-to-html
         :html-head "<link rel=\"stylesheet\" href=\"assets/css/main.css\" type=\"text/css\"/>"
         :html-preamble (lambda (project)
                          (let ((buffer (find-file-noselect (buffer-file-name))))
                            (unless (string= "ryuslash.org"
                                             (car (org-publish-find-property (buffer-file-name) :title project)))
                              (publish-format-reading-time
                               (publish-calculate-reading-time buffer)))))
         :auto-sitemap t
         :sitemap-filename "index.org"
         :sitemap-title "ryuslash.org"
         :sitemap-format-entry publish-org-sitemap-format-entry
         :sitemap-style list
         :sitemap-function publish-org-sitemap
         :sitemap-sort-files anti-chronologically)
        ("rss"
         :base-directory "posts/"
         :base-extension "org"
         :html-link-home "https://ryuslash.org/"
         :rss-link-home "https://ryuslash.org/"
         :html-link-use-abs-url t
         :rss-extension "xml"
         :publishing-directory "public"
         :publishing-function (org-rss-publish-to-rss)
         :section-number nil
         :exclude ".*"
         :include ("index.org")
         :table-of-contents nil)
        ("all" :components ("posts" "rss"))))

(provide 'publish)
;;; publish.el ends here