;; -*- lexical-binding: t -*-

(require 'ox)
(require 'subr-x)
(require 'xmlgen)

(defun expand-file-name* (name default-directory)
  (expand-file-name name (concat "/" default-directory)))

(org-export-define-derived-backend 'ennu-html 'html
  :translate-alist
  '((inner-template . ennu-html-inner-template))
  :options-alist
  '((:html-inline-image-rules
     nil nil '(("image" . "\\.\\(jpeg\\|jpg\\|png\\|gif\\|svg\\)\\'")) t)
    (:summary "SUMMARY" nil nil parse)
    (:thumbnail "THUMBNAIL" nil nil t)
    (:translation-group "TRANSLATION_GROUP" nil nil t)))

(defun ennu-html-inner-template (contents info)
  (concat
   ;; Table of contents
   (let ((depth (plist-get info :with-toc)))
     (when depth (org-html-toc depth info)))
   ;; Beginning of h-entry
   "<article class=\"h-entry\">"
   ;; Title
   (format "<h1 class=\"p-name\">%s</h1>\n"
           (org-export-data (plist-get info :title) info))
   ;; Author and date
   (let ((author (when (plist-get info :with-author)
                   (plist-get info :author)))
         (date (when (plist-get info :with-date)
                 (org-export-get-date info))))
     (when (or author date)
       (xmlgen `(p "Published"
                   ,@(when author
                       `(" by "
                         (a :class "p-author h-card"
                            :href ,(ennu--absolute-uri "")
                            ,(car (plist-get info :author)))))
                   ,@(when date
                       `(" on "
                         (time :class "dt-published"
                               :datetime ,(org-export-get-date info "%Y-%m-%d 12:00:00")
                               ,(org-export-get-date info "%B %d, %Y"))))))))
   ;; Interlanguage language links
   (format "<p>In other languages: %s</p>"
           (mapconcat
            (lambda (translation)
              (let ((lang (ennu-post-language translation))
                    (slug (ennu-post-slug translation)))
                (replace-regexp-in-string
                 "<a " (format "<a hreflang=\"%s\" " lang)
                 (ennu-export-post slug lang (plist-get info :backend)))))
            (plist-get info :translations)
            ", "))
   ;; Tags
   (format "<p>Tags: %s</p>"
           (mapconcat
            (lambda (tag)
              (replace-regexp-in-string
               "<a " "<a class=\"p-category\" "
               (ennu-export-tag (ennu-add-tongue-suffix tag (plist-get info :language))
                                tag (plist-get info :backend))))
            (plist-get info :filetags) ", "))
   ;; Summary
   (format "<div class=\"p-summary\">%s</div>"
           (org-export-data (plist-get info :summary) info))
   ;; Document contents
   (format "<div class=\"e-content\">%s</div>" contents)
   ;; Footnotes section
   (org-html-footnote-section info)
   "</article>"))

;; TODO: Pass title through org-export-data-with-backend or something
;; similar in order to export org syntax in title
(defun ennu-export-post (path desc backend)
  (let ((filename (concat (expand-file-name path (ennu-setting :posts-directory))
                      ".org")))
    (xmlgen `(a :href ,(expand-file-name*
                        path (ennu-setting :posts-directory))
                ,(or desc (ennu-post-title (ennu-read-post filename)))))))

(org-link-set-parameters
 "post" :export 'ennu-export-post)

(defun ennu-export-image (path desc backend)
  (let ((img `(img :src ,(expand-file-name*
                          (ennu-image-output-filename
                           path (ennu-setting :default-image-width))
                          (ennu-setting :images-directory)))))
    (xmlgen (if (ennu-setting :image-link-width)
                `(a :href ,(expand-file-name*
                            (ennu-image-output-filename
                             path (ennu-setting :image-link-width))
                            (ennu-setting :images-directory))
                    ,img)
              img))))

(org-link-set-parameters
 "image" :export 'ennu-export-image)

(defun ennu-export-thumbnail (path desc backend)
  (xmlgen
   `(img :src ,(expand-file-name*
                (ennu-image-output-filename
                 path (ennu-setting :thumbnail-image-width))
                (ennu-setting :images-directory)))))

(org-link-set-parameters
 "thumbnail" :export 'ennu-export-thumbnail)

(defun ennu-export-video (path desc backend)
  (let ((video-directory (ennu-setting :video-directory)))
    (xmlgen
     `(video :src ,(expand-file-name* path video-directory)
             :poster ,(expand-file-name* (ennu-video-poster path) video-directory)
             :preload "none"
             :controls ""))))

(org-link-set-parameters
 "video" :export 'ennu-export-video)

(defun ennu-export-static (path desc backend)
  (xmlgen
   `(a :href ,(expand-file-name* path (ennu-setting :static-directory))
       ,desc)))

(org-link-set-parameters
 "static" :export 'ennu-export-static)

(org-link-set-parameters
 "tangle" :export 'ennu-export-static)

(defun ennu-export-tag (tag desc backend)
  (xmlgen
   `(a :href ,(expand-file-name* tag (ennu-setting :tag-directory))
       ,(or desc tag))))

(org-link-set-parameters
 "tag" :export 'ennu-export-tag)

(provide 'ennu-html)