require 'net/ftp'
require 'tempfile'

module GVBus
  class FTP
    include ActionView::Helpers::NumberHelper

    def initialize(options = {})
      @options = options.merge(encoding: 'iso-8859-1')
    end

    def download(file_path)
      directory = File.dirname(file_path)
      file = File.basename(file_path)

      tempfile = Tempfile.new('gvbus_', @options)
      transferred = 0

      Rails.logger.info("Downloading => #{directory}/#{file}")

      ftp = connect_to_ftp
      ftp.chdir(directory)
      ftp.getbinaryfile(file, tempfile.path, 1024) do |data|
        transferred += data.size
        output_download_progress(transferred) if transferred % 1048576 == 0 # Every MB
      end
      output_download_progress(transferred)
      ftp.close

      Rails.logger.info('Download complete!')

      tempfile
    end

    def upload(file_path, ftp_dir, ftp_file_name = nil)
      ftp_file_name ||= File.basename(file_path)
      file = File.new(file_path)

      Rails.logger.info("Uploading => #{file_path} to #{ftp_dir}/#{ftp_file_name}")
      ftp = connect_to_ftp
      ftp.chdir(ftp_dir)
      ftp.putbinaryfile(file, ftp_file_name)
      ftp.close
      Rails.logger.info('Upload completed!')
      file.close
      true
    end

    def ftp_file(date)
      download("Dados do dia #{date.strftime('%d-%m-%Y')}/Dados_Funcionarios.txt")
    end

    def generate_sorted_file
      date = Date.yesterday
      benefits_file = ftp_file(date)

      sorted_benefits_file = Tempfile.new('gvbus_sorted_')

      system "LC_ALL='C' sort --field-separator=';' -k 2,2 -k 1,1 #{benefits_file.path} > #{sorted_benefits_file.path}"

      upload(sorted_benefits_file.path, "Dados do dia #{date.strftime('%d-%m-%Y')}", 'Dados_Funcionarios_Sorted_CNPJ.txt')
    end

    private

    def output_download_progress(size)
      size = number_to_human_size(size)
      Rails.logger.info("Downloaded #{size}")
    end

    def connect_to_ftp
      host = Rails.application.secrets.gvbus_ftp_host
      user = Rails.application.secrets.gvbus_ftp_username
      pass = Rails.application.secrets.gvbus_ftp_password

      ftp = ExtendedPassiveFTP.new(host)
      ftp.passive = true
      ftp.open_timeout = 20
      ftp.login(user, pass)
      ftp
    end

    class ExtendedPassiveFTP < Net::FTP
      def makepasv
        parse229(sendcmd('EPSV'))
      end
    end
  end
end