% :- dynamic .




create_server(Port) :-
  tcp_socket(Socket),
  tcp_bind(Socket, Port),
  tcp_listen(Socket, 5),
  acceptor_loop(Socket).

on_thread_exit(Ip) :-
  writeln(user_error, "Exiting On Socket Closed!"),
  format(user_error,"Disconnection from: ~w\n",[Ip]),
  flush_output(user_error).

% the client handling threaad doesn't die on error from the socket
% need to make this happen I think
acceptor_loop(Socket) :-
  tcp_accept(Socket,Client,Ip),
  thread_create(handle_client(Client,Ip),ThreadId,[at_exit(on_thread_exit(Ip))]),
  format("Connection from: ~w\n",[Ip]),
  flush_output,
  acceptor_loop(Socket).

output(Stream,String) :-
  string_concat(String,"\r",Line),
  writeln(Stream,Line),
  flush_output(Stream).

handle_client(Client,Ip) :-
  % thread_at_exit((writeln("DO WE EXIT?!"),flush_output)),
  tcp_open_socket(Client,Stream),
  output(Stream,"Welcome to Prolog Communications!"),
  client_loop(Stream).

client_loop(Stream) :-
  read_string(Stream, "\n", "\r", End, Line),
  ( End == -1 ->

    writeln("Exiting thread...."),
    thread_exit("Socket Closed") ;

    output(Stream,Line),
    % close(Stream),
    writeln("everything is fine, looping for more input..."),
    client_loop(Stream)).

start :- create_server(8000).