trema/pio

# frozen_string_literal: true

require 'bindata'

require 'pio/ethernet_header'
require 'pio/lldp/chassis_id_tlv'
require 'pio/lldp/optional_tlv'
require 'pio/lldp/port_id_tlv'
require 'pio/lldp/ttl_tlv'

module Pio
  # LLDP frame parser and generator.
  class Lldp
    # LLDP frame
    class Frame < BinData::Record
      include Ethernet

      endian :big

      ethernet_header ether_type: Ethernet::Type::LLDP
      chassis_id_tlv :chassis_id
      port_id_tlv :port_id
      ttl_tlv :ttl, initial_value: 120
      array(:optional_tlv,
            type: :optional_tlv,
            read_until: -> { element.end_of_lldpdu? })

      def dpid
        chassis_id.to_i
      end

      def port_description
        get_tlv_field 4, 'port_description'
      end

      def system_name
        get_tlv_field 5, 'system_name'
      end

      def system_description
        get_tlv_field 6, 'system_description'
      end

      def system_capabilities
        get_tlv 7
      end

      def management_address
        get_tlv_field 8, 'management_address'
      end

      def organizationally_specific
        get_tlv 127
      end

      private

      def get_tlv(tlv_type)
        tlv = optional_tlv.find do |each|
          each['tlv_type'] == tlv_type
        end
        tlv['tlv_value'] if tlv
      end

      def get_tlv_field(tlv_type, name)
        tlv = get_tlv(tlv_type)
        tlv[name] if tlv
      end
    end
  end
end