-module(primes).
-compile(export_all).

main() ->
  pg:create(numbers),
  Server_PID = spawn(?MODULE,server,[]),
  register(server,Server_PID),
  ok.

server()     -> server(2,[]).
server(50,L) -> io:format("Primes: ~p~n",[L]);
server(N,L)  ->
  Num_PID = spawn(?MODULE,number,[N]),
  pg:join(numbers,Num_PID),
  pg:send(numbers,tick),
  receive
    hit ->
      flush(),
      server(N+1,L)
  after 100 ->
      server(N+1,[N|L])
  end.

number(N)   -> receive {pg_message,_,_,tick} -> number(N,1) end.
number(N,I) ->
  receive
    {pg_message,_,_,tick} ->
      if
        N =:= I ->
          server ! hit,
          number(N,1);
        true ->
          number(N,I+1)
      end
  end.

flush() ->
  receive _ -> flush()
  after   0 -> ok end.