module GeoNamesAPI
  class Country < GeoNamesAPI::Object

    METHOD = "countryInfoJSON"
    ID = "country"

    EXPORT_BASE_URL = "http://download.geonames.org/export/zip/"
    EXPORT_HEADERS = %W(country_code postal_code place_name admin_name1 admin_code1 admin_name2 admin_code2 admin_name3 admin_code3 latitude longitude accuracy)

    def postal_code_export
      zip_data = open(postal_code_export_url) { |f| f.binmode; f.read }
      stream = lambda { return zip_data.slice!(0, 256) }
      csv = EXPORT_HEADERS.join("\t") + "\n"
      Zip::Archive.open_buffer(stream) do |archive|
        archive.each do |f|
          csv << f.read if f.name =~ /\A#{country_code}/
        end
      end
      csv
    end
    
    def postal_code_csv
      CSV.parse(postal_code_export, headers: true, col_sep: "\t", header_converters: :symbol)
    end
    
    def postal_code_export_url
      EXPORT_BASE_URL + country_code + ".zip"
    end
    
  end
end