%%% Copyright (c) 2017, NORDUnet A/S.
%%% See LICENSE for licensing information.

-module(plopcontrol).
-export([start_link/0, server_start/2]).

start_link() ->
    case gen_tcp:listen(application:get_env(plop, plopcontrolport, 0), [binary, {packet, line},
                                                                        {active, false},
                                                                        {ip, {127, 0, 0, 1}}]) of
        {ok, ListenSocket} ->
            proc_lib:start_link(?MODULE,server_start,[self(), ListenSocket]);
        {error,Reason} ->
            {error,Reason}
    end.

server_start(Parent, ListenSocket) ->
    proc_lib:init_ack(Parent, {ok, self()}),
    {ok, Port} = inet:port(ListenSocket),
    {ok, PlopcontrolFile} = application:get_env(plop, plopcontrol),
    atomic:replacefile(PlopcontrolFile, integer_to_list(Port)),
    acceptloop(ListenSocket).

acceptloop(ListenSocket) ->
    {ok, Socket} = gen_tcp:accept(ListenSocket),
    commandloop(Socket),
    acceptloop(ListenSocket).

commandloop(Socket) ->
    case gen_tcp:recv(Socket, 0) of
        {ok, Packet} ->
            Answer = command(Packet),
            gen_tcp:send(Socket, Answer),
            commandloop(Socket);
        {error, _Reason} ->
            ok
    end.

command(<<"reload\n">>) ->
    plopconfig:load_config(),
    "reload completed\n";

command(<<"configversion\n">>) ->
    {ok, ConfigVersion} = plopconfig:get_env(version),
    io_lib:format("~w\n", [ConfigVersion]);

command(_) ->
    "unknown command\n".