asciidoc_html_build.sh

#!/usr/bin/env bash

# SPDX-FileCopyrightText: © 2024 Sebastian Davids <sdavids@gmx.de>
# SPDX-License-Identifier: Apache-2.0

set -Eeu -o pipefail -o posix

# https://hub.docker.com/r/asciidoctor/docker-asciidoctor
readonly asciidoctor_version=1.77.0
readonly asciidoctor_image="asciidoctor/docker-asciidoctor:${asciidoctor_version}"

# https://stackoverflow.com/a/3915420
# https://stackoverflow.com/questions/3915040/how-to-obtain-the-absolute-path-of-a-file-via-shell-bash-zsh-sh#comment100267041_3915420
command -v realpath >/dev/null 2>&1 || realpath() {
  if [ -h "$1" ]; then
    # shellcheck disable=SC2012
    ls -ld "$1" | awk '{ print $11 }'
  else
    echo "$(
      cd "$(dirname -- "$1")" >/dev/null
      pwd -P
    )/$(basename -- "$1")"
  fi
}

while getopts ':fno:s:' opt; do
  case "${opt}" in
    f)
      force='true'
      ;;
    n)
      no_cache='true'
      ;;
    o)
      host_build_dir="${OPTARG}"
      ;;
    s)
      host_src_dir="${OPTARG}"
      ;;
    ?)
      echo "Usage: $0 -d <directory> [-n]" >&2
      exit 1
      ;;
  esac
done

readonly force="${force:-false}"
readonly no_cache="${no_cache:-false}"

host_src_dir="${host_src_dir:-$PWD/src}"

if [ ! -d "${host_src_dir}" ]; then
  printf "The source directory '%s' does not exist\n" "${host_src_dir}" >&2
  exit 1
fi

host_src_dir="$(realpath "${host_src_dir}")"
readonly host_src_dir

host_build_dir="${host_build_dir:-$PWD/build}"

if [ "${force}" = 'true' ] \
  && [ -d "${host_build_dir}" ] \
  && [ "${host_build_dir}" != "$PWD" ] \
  && [ "${host_build_dir}" != '.' ]; then

  rm -rf "${host_build_dir}"
fi

mkdir -p "${host_build_dir}"

host_build_dir="$(realpath "${host_build_dir}")"
readonly host_build_dir

readonly src_dir='/documents'
readonly out_dir='/mnt/out'

readonly build_dir="/tmp/build"

cmd="asciidoctor -R ${src_dir} -D ${build_dir}"
cmd+=' -r asciidoctor-diagram'
cmd+=' -a toc'
# https://docs.asciidoctor.org/asciidoctor/latest/html-backend/manage-images/#embed-images-with-the-data-uri-attribute
cmd+=' -a data-uri'
# https://docs.asciidoctor.org/asciidoc/latest/macros/icons-font/#enable-font-based-icons
cmd+=' -a icons=font'
# https://github.com/asciidoctor/asciidoctor/issues/4622
if [ -d "${host_src_dir}/fonts" ]; then
  awesome="$(find "${host_src_dir}/fonts" -type f -name fontawesome-webfont\*.woff2)"
  if [ -n "${awesome}" ]; then
    # https://docs.asciidoctor.org/asciidoctor/latest/html-backend/local-font-awesome/#switch-to-your-local-font-awesome-assets
    cmd+=' -a iconfont-remote!'
  fi
  unset awesome
fi
# https://docs.asciidoctor.org/asciidoctor/latest/html-backend/custom-stylesheet/#configure-the-styles-directory
cmd+=' -a stylesdir=css'
# https://docs.asciidoctor.org/asciidoctor/latest/html-backend/default-stylesheet/#disable-or-modify-the-web-fonts
cmd+=' -a webfonts!'
if [ "${no_cache}" != 'false' ]; then
  # https://docs.asciidoctor.org/diagram-extension/latest/generate/#diagram_caching
  cmd+=' -a diagram-nocache-option'
fi
cmd+=" '**/*.adoc'"
if [ "${no_cache}" = 'false' ]; then
  cmd+=" && find ${build_dir} -depth -name '_includes' -type d -exec rm -rf {} \; && cp -r -f ${build_dir}/* ${out_dir}"
else
  cmd+=" && cd ${build_dir}"
  cmd+=" && find . -name '_includes' -prune -o \( -type f -name \*.css -o -name \*.html \) -exec cp --parents {} ${out_dir} \;"
fi
readonly cmd

mkdir -p "${host_build_dir}"

docker run \
  --user "$(id -u):$(id -g)" \
  --rm \
  --security-opt='no-new-privileges=true' \
  --cap-drop=all \
  --mount "type=bind,src=${host_src_dir},dst=${src_dir},readonly" \
  --mount "type=bind,src=${host_build_dir},dst=${out_dir}" \
  --env XDG_CACHE_HOME='/tmp' \
  "${asciidoctor_image}" \
  sh -c "${cmd}"

# https://github.com/asciidoctor/asciidoctor/issues/4622
if [ -d "${host_src_dir}/fonts" ]; then
  fonts="$(find "${host_src_dir}/fonts" -type f -name \*.woff2)"
  if [ -n "${fonts}" ]; then
    find "${host_build_dir}" -type f -name \*.html -exec sh -c 'mkdir -p "$(dirname "$0")/fonts";' {} \;
    echo "${fonts}" | while IFS= read -r f; do
      find "${host_build_dir}" -type d -name fonts -exec cp -f "${f}" {} \;
    done
  fi
fi

# https://github.com/asciidoctor/asciidoctor/issues/4622
if [ -d "${host_src_dir}/css" ]; then
  css_files="$(find "${host_src_dir}/css" -type f -name \*.css)"
  if [ -n "${css_files}" ]; then
    find "${host_build_dir}" -type f -name \*.html -exec sh -c 'mkdir -p "$(dirname "$0")/css";' {} \;
    echo "${css_files}" | while IFS= read -r f; do
      find "${host_build_dir}" -type d -name css -exec cp -f "${f}" {} \;
    done
  fi
fi