% Copyright (c) 2025 Onomondo ApS & sysmocom - s.f.m.c. GmbH. All rights reserved.
%
% SPDX-License-Identifier: AGPL-3.0-only
%
% Author: Harald Welte <hwelte@sysmocom.de> / sysmocom - s.f.m.c. GmbH
% Author: Philipp Maier <pmaier@sysmocom.de> / sysmocom - s.f.m.c. GmbH

-module(esipa_asn1_codec).

-export([decode_ipa_to_eim/1, encode_eim_to_ipa/1]).

decode_ipa_to_eim(Data) ->
    'SGP32Definitions':decode('EsipaMessageFromIpaToEim', Data).

% The ASN.1 encoder that is generated using erlang's (asn1ct) encodes an additional constructed tag in front of the
% actual EsipaMessageFromEimToIpa. This is probably due to the fact that EsipaMessageFromEimToIpa is a choice
% definition (anonymous) that is misinterpreted by the ASN.1 compiler. It is conspicuous that chosen tag for the excess
% constructed tag is always the tag of the chosen type. In general one would expect to see the tag of the chosen type
% followed by the length+value of the chosen type. (see also ITU-T Rec. X.690, section 8.13). In any case, since we are
% at the top level, we can work around this by directly encoding the chosen type.
encode_eim_to_ipa({getEimPackageResponse, EimToIpaChoice}) ->
    'SGP32Definitions':encode('GetEimPackageResponse', EimToIpaChoice);
encode_eim_to_ipa({authenticateClientResponseEsipa, EimToIpaChoice}) ->
    'SGP32Definitions':encode('AuthenticateClientResponseEsipa', EimToIpaChoice);
encode_eim_to_ipa({initiateAuthenticationResponseEsipa, EimToIpaChoice}) ->
    'SGP32Definitions':encode('InitiateAuthenticationResponseEsipa', EimToIpaChoice);
encode_eim_to_ipa({getBoundProfilePackageResponseEsipa, EimToIpaChoice}) ->
    'SGP32Definitions':encode('GetBoundProfilePackageResponseEsipa', EimToIpaChoice);
encode_eim_to_ipa({cancelSessionResponseEsipa, EimToIpaChoice}) ->
    'SGP32Definitions':encode('CancelSessionResponseEsipa', EimToIpaChoice);
encode_eim_to_ipa(emptyResponse) ->
    {ok, <<>>};
encode_eim_to_ipa(EimToIpa) ->
    'SGP32Definitions':encode('EsipaMessageFromEimToIpa', EimToIpa).