# frozen_string_literal: true

class Netdisco
  class LLDP < XDP
    MIB         = "1.0.8802.1.1.2" # lldpMIB
    OID         = {
      # http://standards.ieee.org/getieee802/download/802.1AB-2009.pdf
      # finding IP address for LLDP neighbour as of JunOS 13.3R1 and IOS 15.0(2)SG8 is not practical
      # ifsubtype is ifindex but value 0 for JunOS neighbours
      # ifsubtype is systemportnumber for IOS neighbours (what ever that is)
      # luckily some IP address is in the OID key itself, while dodgy, better than nothing
      #   in JunOS it was some random RFC1918 address in VRF interface, not something I could poll
      #   .1.0.8802.1.1.2.1.4.2.1.3.0.134.10.1.4.10.0.0.4
      #   in IOS it was usable address
      #   .1.0.8802.1.1.2.1.4.2.1.3.0.257.1.1.4.62.243.146.245
      #   (1.4 is IPv4)
      #  as well LocPortId/RemPortId is hard, it is 'local' (snmpifindex really) in JunOS, but ifName in IOS
      lldpLocPortId:           "1.0.8802.1.1.2.1.3.7.1.3",
      lldpRemChassisIdSubtype: "1.0.8802.1.1.2.1.4.1.1.4", # CSCO and JNPR use 4 (MAC address) rendering ChassisID useless
      lldpRemChassisId:        "1.0.8802.1.1.2.1.4.1.1.5",
      lldpRemPortIdSubtype:    "1.0.8802.1.1.2.1.4.1.1.6",
      lldpRemPortId:           "1.0.8802.1.1.2.1.4.1.1.7",
      lldpRemSysName:          "1.0.8802.1.1.2.1.4.1.1.9",
      lldpRemManAddrIfSubtype: "1.0.8802.1.1.2.1.4.2.1.3",
    }
    PEERS_BY    = OID[:lldpRemChassisId]
    PortSubType = {
      mac_address: 3,
    }

    private
      def make_peers
        peers = []
        @mib.by_oid(PEERS_BY).each do |_, vb|
          peer          = Peer.new
          peer_id       = vb.oid_id(PEERS_BY)
          peer.oid      = get_oid_hash peer_id
          ip            = @mib.by_partial(OID[:lldpRemManAddrIfSubtype], peer_id)
          peer.raw_ip   = ip.oid[-4..-1].join(".") if ip # FIXME: IPv4 specific
          peer.raw_ip ||= "192.0.2.255" # sometimes we can't fnd any IP (EX2200 talking Arista found)
          peer.raw_name = @mib[OID[:lldpRemSysName], peer_id].value
          peer.ip       = get_ip(peer.raw_ip, peer.raw_name)
          peer.dst      = @mib[OID[:lldpRemPortId], peer_id].value
          if @mib[OID[:lldpRemPortIdSubtype], peer_id].value.to_i == PortSubType[:mac_address]
            peer.dst = peer.dst&.each_char&.map { |e| "%02x" % e.ord }&.join&.scan(/..../).join(".")
          end
          peer.src = @mib[OID[:lldpLocPortId], peer_id[1]].value rescue nil
          peers << peer
        end
        peers
      end
  end
end