-module(test1).
-export([start_server/0]).

start_server() -> 
    spawn( fun() -> server(4000) end ).

server(Port) ->
    {ok, Socket} = gen_udp:open( Port, [binary] ),
    io:format( "socked opened ~p~n ", [Socket]),
    loop(Socket).

loop(Socket) ->
    receive
        {udp, Socket, Host, Port, Bin} -> 
            Adr = binary_to_list(getadr(Bin)),
            io:format( "got: ~p~n", [{Host, Port, Adr}]),
            dispatch( Adr, Bin ),
            loop(Socket)
    end.

%% extract osc event address
getadr( Bin ) ->
    Len = msglen( Bin, 0 ),
    {Msg, _} = split_binary(Bin, Len),
    Msg.

%% Get Length of the first \0 based string 
msglen(<<0, _/binary>>, Len) -> Len;

msglen(Bin, Len) -> 
    { _, Next} = split_binary( Bin, 1 ),
    msglen( Next, Len + 1).

%% send message to host/port
send( Host, Port, Bin) ->
    {ok, Socket} = gen_udp:open( 0, [binary] ),
    ok = gen_udp:send( Socket, Host, Port, Bin ),
    gen_udp:close( Socket ).


%% define where to send the messages 
dispatch( "/osc/test" ++ _, Bin ) -> 
    io:format( "TEST ~p~n", [Bin] ),
    send( "localhost", 4001, Bin);

dispatch( "/osc/midi" ++ _, Bin ) -> 
    io:format( "MIDI ~p~n", [Bin] ),
    send( "localhost", 4002, Bin);

dispatch( _, _ ) -> 
    io:format( "UNKNOWN ~n" ).