org2html

#!/usr/bin/env bash

# @file      org2html
# @brief     Org-Mode files support for CGit about pages and text blobs rendering.
# @copyright 2023-2024 Alexandre Martos <contact@amartos.fr>
# @license   GPLv3

CGIT_APPDIR="${CGIT_APPDIR:-/usr/share/cgit}"
CGIT_CONFIG="${CGIT_CONFIG:-/etc/cgitrc}"
CGIT_CACHE="${CGIT_CACHE:-/var/cache/cgit}"
if [ -f "$CGIT_CONFIG" ] && grep -q cache-root "$CGIT_CONFIG"
then
    CGIT_CACHE=$(awk 'BEGIN {FS="="} /^cache-root/ {print $2}' "$CGIT_CONFIG")
fi

CACHE="$CGIT_CACHE/org2html"
ORG2HTML_CSS_PATH="${ORG2HTML_CSS_PATH:-$CGIT_APPDIR/css/org2html.css}"
INIT="$CACHE/init.el"

usage() {
    echo "usage: $(basename $0) [-hvw] < FILE.org"
}

version() {
    echo "org2html v1.1.0"
}

license() {
    cat <<EOF
$(version) Copyright (C) 2023-2024 Alexandre Martos <contact@amartos.fr>

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/>.
EOF
}

phelp() {
    cat <<EOF
$(usage)

This program converts the content of an Org-Mode file to HTML (body
only). It is designed to be used by CGit as a converter for filters.

[INPUT]

The script takes the Org-Mode file content through STDIN.

[OPTIONS]

-h  print this help
-v  print the version number
-w  print the short license text

[ENVIRONMENT]

CGIT_CONFIG         CGit config file path (defaults to /etc/cgitrc)
CGIT_APPDIR         CGit root directory (defaults to /usr/share/cgit)
CGIT_CACHE          CGit cache directory (defaults to /var/cache/cgit)
ORG2HTML_CSS_PATH   CSS file path (defaults to CGIT_APPDIR/css/org2html.css)

[CONFIGURATION]

The CGit configuration values this script uses (if defined):

cache-root          CGit cache root path (supersedes CGIT_CACHE)

[BUGS]

In case of issues please contact the maintainer at:
https://github.com/amartos/cgit-org2html/issues

[COPYRIGHT]

$(license)
EOF
}

while getopts "hvw" arg
do
      case $arg in
          h) phelp;   exit 0; ;;
          v) version; exit 0; ;;
          w) license; exit 0; ;;
          *) ;;
      esac
done

mkdir -p "$CACHE"
[ ! -f "$INIT" ] && cat > "$INIT"<<EOF
(require 'org)
(require 'ox-html)
(defun org-html-src-block (src-block _contents info)
  "Transcode a SRC-BLOCK element from Org to HTML.
CONTENTS holds the contents of the item.  INFO is a plist holding
contextual information.

This version is the same as the ox-html.el function, except that the
code is enclosed in <pre><code> tags (and not only <pre>), and the
language classes used for the code blocks are those used by prism.js
and highlight.js"
  (if (org-export-read-attribute :attr_html src-block :textarea)
      (org-html--textarea-block src-block)
    (let* ((lang (org-element-property :language src-block))
	   (code (org-html-format-code src-block info))
	   (label (let ((lbl (org-html--reference src-block info t)))
		    (if lbl (format " id='%s'" lbl) "")))
	   (klipsify  (and  (plist-get info :html-klipsify-src)
                            (member lang '("javascript" "js"
					   "ruby" "scheme" "clojure" "php" "html")))))
      (if (not lang) (format "<pre class='example'%s>\n%s</pre>" label code)
	(format "<div class='org-src-container'>\n%s%s\n</div>"
		;; Build caption.
		(let ((caption (org-export-get-caption src-block)))
		  (if (not caption) ""
		    (let ((listing-number
			   (format
			    "<span class='listing-number'>%s </span>"
			    (format
			     (org-html--translate "Listing %d:" info)
			     (org-export-get-ordinal
			      src-block info nil #'org-html--has-caption-p)))))
		      (format "<label class='org-src-name'>%s%s</label>"
			      listing-number
			      (org-trim (org-export-data caption info))))))
		;; Contents.
		(if klipsify
		    (format "<pre><code class='lang lang-%s'%s%s>%s</code></pre>"
			    lang
			    label
			    (if (string= lang "html")
				" data-editor-type='html'"
			      "")
			    code)
		  (format "<pre><code class='lang lang-%s'%s>%s</code></pre>"
                          lang label code)))))))
(defun org-html-example-block (example-block _contents info)
  "Transcode a EXAMPLE-BLOCK element from Org to HTML.
CONTENTS is nil.  INFO is a plist holding contextual
information.

This version is designed to give the exact same output as
org-html-src-block."
  (org-html-src-block example-block _contents info))
(setq org-html-self-link-headlines t)
(defun user/org/cgit-org2html ()
  (org-html-export-as-html nil nil nil t nil)
  (princ (buffer-string))
  )
EOF

STDIN="$(cat)"
SHA="$CACHE/$(echo $STDIN | sha256sum | cut -d' ' -f1)"

if [ ! -f "$SHA.html" ]
then
    echo "$STDIN" > "$SHA.org"
    emacs -Q --batch "$SHA.org" -l "$INIT" -f user/org/cgit-org2html --kill 1>"$SHA.html" 2>/dev/null
    rm "$SHA.org"
fi

echo "<style>$(cat $ORG2HTML_CSS_PATH)</style>"
cat "$SHA.html"