module ImportFile
  extend ActiveSupport::Concern

  # 失敗したインポート処理を一括削除します。
  def self.expire
    self.stucked.find_each do |file|
      file.destroy
    end
  end

  def import_start
    case edit_mode
    when 'create'
      import
    when 'update'
      modify
    when 'destroy'
      remove
    else
      import
    end
  end

  # インポートするファイルの文字コードをUTF-8に変換します。
  # @param [String] line 変換する文字列
  def convert_encoding(line)
    if defined?(CharlockHolmes::EncodingDetector)
      begin
        case user_encoding
        when 'auto_detect'
          encoding = CharlockHolmes::EncodingDetector.detect(line)[:encoding]
        when nil
          encoding = CharlockHolmes::EncodingDetector.detect(line)[:encoding]
        else
          encoding = user_encoding
        end
        line.encode('UTF-8', encoding, universal_newline: true)
      rescue StandardError
        nkf_encode(line)
      end
    else
      nkf_encode(line)
    end
  end

  # インポート完了時のメッセージを送信します。
  def send_message
    sender = User.find(1)
    locale = user.profile.try(:locale) || I18n.default_locale.to_s
    message_template = MessageTemplate.localized_template('import_completed', locale)
    request = MessageRequest.new
    request.assign_attributes({sender: sender, receiver: user, message_template: message_template})
    request.save_message_body
    request.transition_to!(:sent)
  end

  private
  def nkf_encode(line)
    case user_encoding
    when 'auto_detect'
      output_encoding = '-w'
    when 'UTF-8'
      output_encoding = ''
    when 'Shift_JIS'
      output_encoding = '-Sw'
    when 'EUC-JP'
      output_encoding = '-Ew'
    else
      output_encoding = '-w'
    end
    NKF.nkf("#{output_encoding} -Lu", line)
  end

  def create_import_temp_file(attachment)
    tempfile = Tempfile.new(self.class.name.underscore)
    if ENV['ENJU_STORAGE'] == 's3'
      tempfile.write Faraday.get(attachment.expiring_url(10)).body.force_encoding('UTF-8')
    else
      uploaded_file_path = attachment.path
      open(uploaded_file_path){|f|
        f.each{|line|
          tempfile.puts(convert_encoding(line))
        }
      }
    end
    tempfile.close
    tempfile
  end
end