% Copyright (c) Camden Dixie O'Brien
% SPDX-License-Identifier: AGPL-3.0-only

-module(session_server).
-behaviour(gen_server).

-export([start_link/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
		 terminate/2, code_change/3]).

start_link(Socket) ->
	gen_server:start_link(?MODULE, Socket, []).

init(Socket) ->
	ok = ssl:setopts(Socket, [{active, true}]),
	{ok, #{socket => Socket}}.

handle_call(_Request, _From, State) ->
	{reply, ok, State}.

handle_cast(_Msg, State) ->
	{noreply, State}.

handle_info({ssl, Socket, Data}, State) ->
	case 'StudySystemProtocol':decode('Request', Data) of
		{ok, {ping, _}} ->
			{ok, Encoded} = 'StudySystemProtocol':encode(
							  'Response', {ack, 'NULL'}),
			ok = ssl:send(Socket, Encoded);
		{error, {asn1, _Reason}} ->
			{ok, Encoded} = 'StudySystemProtocol':encode(
							  'Response', {error, invalidRequest}),
			ok = ssl:send(Socket, Encoded)
	end,
	{noreply, State};
handle_info({ssl_closed, _Socket}, State) ->
    {stop, normal, State};
handle_info({ssl_error, _Socket, _Reason}, State) ->
    {stop, normal, State};
handle_info(_Info, State) ->
	{noreply, State}.

terminate(_Reason, #{socket := Socket}) ->
	ssl:close(Socket).

code_change(_OldVsn, State, _Extra) ->
	{ok, State}.