-module(win_fail).

-export([rec/0, send/1, go/0]).

-define(PORT_NO, 5678).

-define(NO_OF_PACKETS, 9).

go() ->
    spawn_link(?MODULE, rec, []),
    loop().

loop() ->
    timer:sleep(500),
    send("127.0.0.1"),
    loop().

rec() ->
    {ok, LSock} = gen_tcp:listen(?PORT_NO, [{packet, line}, 
					    {active, false},
					    {reuseaddr, true}]),
    rec_loop(LSock).

rec_loop(LSock) ->
    {ok, Sock} = gen_tcp:accept(LSock),
    inet:setopts(Sock, [{packet, line}]),
    receive_all(Sock, 1),
    io:format("Done~n"),
    ok = gen_tcp:close(Sock),
    rec_loop(LSock).

receive_all(Sock, No) when No =< ?NO_OF_PACKETS ->
    {ok, Line} = gen_tcp:recv(Sock, 0, 10000),
    case make_packet(No) of
	Line -> 
	    io:format("No ~p ok~n", [No]);
	_Other ->
	    io:format("Expected ~p, Got ~p~n", [make_packet(No), Line]),
	    flush(Sock),
	    exit(bad)
    end,
    
    receive_all(Sock, No + 1);

receive_all(_Sock, _) ->
    done.

flush(Sock) ->
    case gen_tcp:recv(Sock, 0, 10000) of
	{ok, Line} ->
	    io:format("Flush got ~p~n", [Line]),
	    flush(Sock);
	{error, closed} ->
	    io:format("Flush closed~n")
    end.

send(Host) ->
    {ok, Sock} = gen_tcp:connect(Host, ?PORT_NO, 
                                 [{packet, 0}]),
    do_send(Sock, 1),

    ok = gen_tcp:close(Sock).

do_send(Sock, No) when No =< ?NO_OF_PACKETS ->
    ok = gen_tcp:send(Sock, 
		      make_packet(No)),
    do_send(Sock, No + 1);

do_send(_,_) ->
    ok.

cr() ->
    [16#d, 16#a].

make_packet(No) ->
    lists:duplicate(30, $A + No - 1) ++ cr().