-module(glome@core@authentication).
-compile(no_auto_import).

-export([authenticate/2]).
-export_type([access_token/0]).

-type access_token() :: {access_token, binary()}.

-spec authenticate(nerf@websocket:connection(), access_token()) -> {ok,
                                                                    binary()} |
    {error, glome@core@error:glome_error()}.
authenticate(Connection, Access_token) ->
    case authentication_phase_started(Connection) of
        {error, _try} -> {error, _try};
        {ok, _@1} ->
            Auth_message = glome@core@json:encode(
                [glome@core@json:json_element(<<"type"/utf8>>, <<"auth"/utf8>>),
                 glome@core@json:json_element(
                     <<"access_token"/utf8>>,
                     erlang:element(2, Access_token)
                 )]
            ),
            nerf@websocket:send(Connection, Auth_message),
            case begin
                _pipe = nerf@websocket:'receive'(Connection, 500),
                gleam@result:map_error(
                    _pipe,
                    fun(_) ->
                        {authentication_error,
                         <<"authentication failed! Auth result message not received!"/utf8>>}
                    end
                )
            end of
                {error, _try@1} -> {error, _try@1};
                {ok, {text, Auth_response}} ->
                    case begin
                        _pipe@1 = glome@core@json:string_field(
                            Auth_response,
                            <<"type"/utf8>>
                        ),
                        gleam@result:map_error(
                            _pipe@1,
                            fun(_) ->
                                {authentication_error,
                                 <<"authentication failed! Auth result message has no field [ type ]!"/utf8>>}
                            end
                        )
                    end of
                        {error, _try@2} -> {error, _try@2};
                        {ok, Type_field} ->
                            case Type_field of
                                <<"auth_ok"/utf8>> ->
                                    {ok,
                                     <<"Authenticated connection established"/utf8>>};

                                <<"auth_invalid"/utf8>> ->
                                    {error,
                                     {authentication_error,
                                      <<"Invalid authentication"/utf8>>}}
                            end
                    end
            end
    end.

-spec authentication_phase_started(nerf@websocket:connection()) -> {ok,
                                                                    binary()} |
    {error, glome@core@error:glome_error()}.
authentication_phase_started(Connection) ->
    case begin
        _pipe = nerf@websocket:'receive'(Connection, 500),
        gleam@result:map_error(
            _pipe,
            fun(_) ->
                {authentication_error,
                 <<"could not start auth phase! Auth message not received!"/utf8>>}
            end
        )
    end of
        {error, _try} -> {error, _try};
        {ok, {text, Initial_message}} ->
            case begin
                _pipe@1 = glome@core@json:string_field(
                    Initial_message,
                    <<"type"/utf8>>
                ),
                gleam@result:map_error(
                    _pipe@1,
                    fun(_) ->
                        {authentication_error,
                         <<"could not start auth phase! Auth message has no field [ type ]!"/utf8>>}
                    end
                )
            end of
                {error, _try@1} -> {error, _try@1};
                {ok, Auth_required} ->
                    case Auth_required of
                        <<"auth_required"/utf8>> ->
                            {ok, Auth_required};

                        _@1 ->
                            {error,
                             {authentication_error,
                              <<"Something went wrong. Authentication phase not started!"/utf8>>}}
                    end
            end
    end.