-module(erlmld_sup).

-behaviour(supervisor).

%% API
-export([start_link/1]).
%% Supervisor callbacks
-export([init/1]).

%%====================================================================
%% API functions
%%====================================================================

start_link(Opts) ->
    Regname = regname(?MODULE, Opts),
    supervisor:start_link({local, Regname}, ?MODULE, [Regname, Opts]).

%%====================================================================
%% Supervisor callbacks
%%====================================================================

init([Regname,
      #{record_processor := RecordProcessor,
        record_processor_data := RecordProcessorData,
        listen_ip := ListenIP,
        listen_port := ListenPort,
        stream_type := StreamType} =
          Opts]) ->
    WorkerSupName = regname(erlmld_wrk_sup, Opts),
    AcceptorName = regname(erlmld_tcp_acceptor, Opts),
    RunnerName = regname(erlmld_runner, Opts),

    {ok, ListenSocket, ActualPort} = erlmld_tcp_acceptor:listen(ListenIP, ListenPort),
    error_logger:info_msg("~p listening on ~p~n", [Regname, ActualPort]),

    %% prepare MLD .properties file:
    {ok, PropertiesPathname} =
        erlmld_runner:build_properties(
            maps:put(port, ActualPort, Opts)),

    SupFlags =
        #{strategy => rest_for_one,
          intensity => 10,
          period => 10},

    StartWorker =
        fun(AcceptedSocket) -> erlmld_wrk_sup:start_worker(WorkerSupName, AcceptedSocket) end,

    WorkerSup =
        #{id => wrk_sup,
          type => supervisor,
          shutdown => infinity,
          start =>
              {erlmld_wrk_sup, start_link, [WorkerSupName, RecordProcessor, RecordProcessorData]}},

    TcpAcceptor =
        #{id => tcp_acceptor,
          type => worker,
          shutdown => brutal_kill,
          start => {erlmld_tcp_acceptor, start_link, [AcceptorName, ListenSocket, StartWorker]}},

    MLDRunner =
        #{id => mld_runner,
          type => worker,
          shutdown => brutal_kill,
          start => {erlmld_runner, start_link, [RunnerName, PropertiesPathname, StreamType]}},

    ChildSpecs = [WorkerSup, TcpAcceptor, MLDRunner],

    {ok, {SupFlags, ChildSpecs}}.

%%====================================================================
%% Internal functions
%%====================================================================

regname(Prefix, #{app_suffix := Suffix}) when Suffix /= undefined ->
    binary_to_atom(<<(atom_to_binary(Prefix, utf8))/binary,
                     "_",
                     (atom_to_binary(Suffix, utf8))/binary>>,
                   utf8);
regname(Prefix, _) ->
    Prefix.