module Rubber
  module Dns

    class Base

      attr_reader :env

      def initialize(env)
        @env = env
      end

      def update(host, ip)
        if up_to_date(host, ip)
          puts "IP has not changed for #{host}, not updating dynamic DNS"
        else
          if ! host_exists?(host)
            puts "Creating dynamic DNS: #{host} => #{ip}"
            create_host_record(host, ip)
          else
            puts "Updating dynamic DNS: #{host} => #{ip}"
            update_host_record(host, ip)
          end
        end
      end

      def destroy(host)
        if host_exists?(host)
          puts "Destroying dynamic DNS record: #{host}"
          destroy_host_record(host)
        end
      end

      def hostname(host)
        "#{host}.#{@env.domain}"
      end

      def up_to_date(host, ip)
        # This queries dns server directly instead of using hosts file
        current_ip = nil
        Resolv::DNS.open(:nameserver => [nameserver], :search => [], :ndots => 1) do |dns|
          current_ip = dns.getaddress(hostname(host)).to_s rescue nil
        end
        return ip == current_ip
      end

      def nameserver()
        raise "nameserver not implemented"
      end

      def host_exists?(host)
        raise "host_exists? not implemented"
      end

      def create_host_record(host, ip)
        raise "create_host_record not implemented"
      end

      def destroy_host_record(host)
        raise "destroy_host_record not implemented"
      end

      def update_host_record(host, ip)
        raise "update_host_record not implemented"
      end

    end

  end
end