#!/usr/bin/perl -w

# sudo apt-get install 9menu ifupdown wireless-tools

$dev = shift || 'wlan0';

$SIG{__DIE__} = sub {
  $msg = join '', @_;
  chomp $msg;
  exec qw(9menu -popup -label), 'Choose a network', "$msg:exit";
};

%iwlist = grep defined,
	  map  {
		  m{
		     ESSID:"([^"]+)" .*
		     Encryption\ key:off .*
		     Quality=(\d+)/(\d+)
		  }xs
		  ? ($1, $3 ? $2/$3 : 0)
		  : undef
	       }
	  split /^\s+Cell \d+ - /m, qx(/sbin/iwlist wlan0 scan);

die "no unencrypted networks found\n" unless %iwlist;
@iwlist = sort { $iwlist{$a} <=> $iwlist{$b} || $a cmp $b }
	  keys %iwlist;

printf "[%.2f] $_\n", $iwlist{$_} for @iwlist;

sub ifup
{
  $essid = shift;
  qq(iwconfig $dev essid "$essid" commit; ifup --force $dev)
}

exec '9menu', '-label', 'Choose a network', map { "$_:exec ".ifup($_) } @iwlist;