file_uploader.rb

# frozen_string_literal: true

require "open3"
PandocCommandError = Class.new(StandardError)
class FileUploader < Shrine
  plugin :derivatives, create_on_promote: true
  plugin :versions
  plugin :remove_attachment

  Attacher.derivatives :convert do |original|
    doc = original

    if doc
      output_html = Tempfile.new(%w[pandoc .html], binmode: true)
      _stdout, stderr, status = Open3.capture3 *%W[pandoc -f docx #{doc.path} -t html5 -o #{output_html.path}]

      raise PandocCommandError, stderr.chomp unless status.success?

      output_html.open
      record.body_html = output_html.read.force_encoding('UTF-8')
      output_html.rewind

      { html: output_html }
    end
  end
end