ifad/colore

require 'iso-639'
module Heathen
  class Processor
    DEV_SHM_PATH = '/dev/shm'

    # Converts office documents to their counterpart (e.g. MS Word -> LibreOffice word,
    # or MS Excel -> LibreOffice Sheet) or to PDF. Calls the external 'libreoffice' utility
    # to achieve this.
    # @param: format [String] output format. Must be one of:
    #    pdf - convert to PDF (any libre-office format)
    #    ms  - corresponding Microsoft format
    #    oo  - corresponding LibreOffice format
    def libreoffice( format: )
      suffixes = {
        'pdf' => {
          '.*' => 'pdf',
        },
        'msoffice' => {
          'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'docx',
          'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' => 'xlsx',
          'application/vnd.openxmlformats-officedocument.presentationml.presentation' => 'pptx',
          'application/vnd.oasis.opendocument.text' => 'docx',
          'application/vnd.oasis.opendocument.spreadsheet' => 'xlsx',
          'application/vnd.oasis.opendocument.presentation' => 'pptx',
          'application/zip' => 'docx',
        },
        'ooffice' => {
          'application/msword' => 'odt',
          'application/vnd.ms-word' => 'odt',
          'application/vnd.ms-excel' => 'ods',
          'application/vnd.ms-office' => 'odt',
          'application/vnd.ms-powerpoint' => 'odp',
          'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'odt',
          'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' => 'ods',
          'application/vnd.openxmlformats-officedocument.presentationml.presentation' => 'odp',
        },
        'txt' => {
          '.*' => 'txt'
        }
      }

      raise InvalidParameterInStep.new('format', format) unless suffixes[format.to_s]
      to_suffix = nil
      suffixes[format.to_s].each do |k,v|
        to_suffix = v if job.mime_type =~ /#{k}/
      end
      raise InvalidMimeTypeInStep.new('(various document formats)', job.mime_type) unless to_suffix

      output = nil

      if to_suffix == 'txt'
        executioner.execute(
          Colore::C_.tika_path,
          '--text',
          job.content_file,
          binary: true
        )

        output = executioner.stdout
      else
        target_file = "#{job.content_file}.#{to_suffix}"

        execute_sandboxed_libreoffice(
          '--convert-to', to_suffix,
          '--outdir', sandbox_dir,
          job.content_file,
          '--headless',
        )

        unless File.exist? target_file
          raise ConversionFailed.new("Cannot find converted file (looking for #{File.basename(target_file)})" )
        end

        output = File.read(target_file)
        File.unlink(target_file)
      end

      raise ConversionFailed.new(executioner.last_messages) if executioner.last_exit_status != 0

      job.content = output
    end

    def execute_sandboxed_libreoffice(*params)
      old_tmpdir = ENV['TMPDIR']
      ENV['TMPDIR'] = DEV_SHM_PATH if try_dev_shm

      profile_dir = Dir.mktmpdir('colore-libreoffice')

      executioner.execute(
        Colore::C_.libreoffice_path,
        '-env:SingleAppInstance=false',
        "-env:UserInstallation=file://#{profile_dir}",
        '--norestore',
        *params
      )
    ensure
      ENV['TMPDIR'] = old_tmpdir

      FileUtils.remove_entry profile_dir
    end

    def try_dev_shm
      return false unless File.exist?(DEV_SHM_PATH)

      stat = File.stat(DEV_SHM_PATH)
      stat.directory? && stat.writable?
    end

  end
end