nning/coap

module CoRE
  module CoAP
    module Options
      extend Types

      TOKEN_ON = 19

      # 14 => :user, default, length range, replicable?, decoder, encoder
      OPTIONS = { # name      minlength, maxlength, [default]    defined where:
         1 => [:if_match,       *o256_many(0, 8)],     # core-coap-12 [RFC7252]
         3 => [:uri_host,       *str_once(1, 255)],    # core-coap-12 [RFC7252]
         4 => [:etag,           *o256_many(1, 8)],     # core-coap-12 [RFC7252] !! once in rp
         5 => [:if_none_match,  *presence_once],       # core-coap-12 [RFC7252]
         6 => [:observe,        *uint_once(0, 3)],     # core-observe-07 [RFC7641]
         7 => [:uri_port,       *uint_once(0, 2)],     # core-coap-12 [RFC7252]
         8 => [:location_path,  *str_many(0, 255)],    # core-coap-12 [RFC7252]
        11 => [:uri_path,       *str_many(0, 255)],    # core-coap-12 [RFC7252]
        12 => [:content_format, *uint_once(0, 2)],     # core-coap-12 [RFC7252]
        14 => [:max_age,        *uint_once(0, 4, 60)], # core-coap-12 [RFC7252]
        15 => [:uri_query,      *str_many(0, 255)],    # core-coap-12 [RFC7252]
        17 => [:accept,         *uint_once(0, 2)],     # core-coap-18! [RFC7252]
        TOKEN_ON => [:token,    *o256_once(1, 8, 0)],  # core-coap-12 -> opaq_once(1, 8, EMPTY)
        20 => [:location_query, *str_many(0, 255)],    # core-coap-12 [RFC7252]
        23 => [:block2,         *uint_once(0, 3)],     # core-block-10 [RFC7959, RFC8323]
        27 => [:block1,         *uint_once(0, 3)],     # core-block-10 [RFC7959, RFC8323]
        28 => [:size2,          *uint_once(0, 4)],     # core-block-10 [RFC7959]
        35 => [:proxy_uri,      *str_once(1, 1034)],   # core-coap-12 [RFC7252]
        39 => [:proxy_scheme,   *str_once(1, 255)],    # core-coap-13 [RFC7252]
        60 => [:size1,          *uint_once(0, 4)],     # core-block-10 [RFC7252]
        258 => [:no_response,   *uint_once(0, 1)],     # [RFC7967] -- says default is 0, but we keep it absent
        2049 => [:ocf_accept_content_format_version, *uint_once(0, 2)], # [Michael_Koster] for OCF
        2053 => [:ocf_content_format_version, *uint_once(0, 2)], # [Michael_Koster] for OCF
      }

      # :user => 14, :user, def, range, rep, deco, enco
      OPTIONS_I =
        Hash[OPTIONS.map { |k, v| [v[0], [k, *v]] }]

      # register a new option.
      # Example: CoRE::CoAP::Options.register(4711, :magic_option, *CoRE::CoAP::Options.o256_many(0, 15))
      def self.register(onum, oname, *codec)
        OPTIONS[onum] = v = [oname, *codec]
        OPTIONS_I[oname] = [onum, *v]
      end                       # this assumes no defaulting

      DEFAULTING_OPTIONS = 
        Hash[
          OPTIONS 
            .map { |k, v| [v[0].freeze, v[1].freeze] }
            .select { |k, v| v }
        ].freeze
    end
  end
end