package telnet;

@commands = qw(xEOF SUSP ABORT EOR SE NOP DM BREAK IP 
	       AO AYT EC EL GA SB WILL WONT DO DONT);

@options = qw(BINARY ECHO RCP SGA NAMS STATUS TM RCTE NAOL
	      NAOP NAOCRD NAOHTS NAUHTD NAOFFD NAOVTS NAOVTD
	      NAOLFD XASCII LOGOUT BM DET SUPDUP SUPDUPOUTPUT
	      SNDLOC TTYP EOR TUID OUTMRK TTYLOC 3270REGIME
	      X2PAD NAWS TSPEED LFLOW LINEMODE XDISPLIC ENVIRON
	      AUTHENTICATION);

$state = "NORM";

sub get_command {
    if (defined $commands[$_[0] - 255]) {
	return $commands[$_[0] - 255];
    }
    else {
	return sprintf("[0x%02X]", $_[0]);
    }
}

sub get_option {
    if (defined $options[$_[0]]) {
	return $options[$_[0]];
    }
    else {
	return sprintf("[0x%02X]", $_[0]);
    }
}

sub parse {
    my $c = ord($_[0]);

    if ($state eq "NORM") {
	if ($c == 255) {
	    $state = "IAC";
	}
	return undef;
    }
    elsif ($state eq "IAC") {
	$com = get_command($c);
	if ($com =~ /WILL|WONT|DO|DONT/o) {
	    $state = $com;
	    return undef;
	}

	if ($c == 255) {
	    return undef;
	}
	else {
	    return "IAC $com\n";
	}
    }
    elsif ($state =~ /WILL|WONT|DO|DONT/o) {
	$ret = "IAC $state " . get_option($c) . "\n";
	$state = "NORM";
	return $ret;
    }
    else {
	warn "unknown state, $state";
    }
}

1;