use Math::BigInt;
use LWP::Simple;

## CONFIG HERE

# Url where you post your now playing track
my $announce_url = 'YOUR URL HERE';
# This is a bit silly but I added a random parameter to make the url unguessable
my $security_code = 'YOU PROBABLY WANT SOME KIND OF AUTH WITH YOUR ANNOUNCE URL';
# Where to find your Spotify configuration - the location below - with username and login replaced should be the default
my $spotify_dir = 'C:\Documents and Settings\YOURUSERNAME\Application Data\Spotify\Users\YOURLOGIN-user';


## Base 62 coding of hexadecimal track IDS
my @alphabet = split '', '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
my $base = 62;
sub base62_encode {
  my $hex = shift;
  $h = Math::BigInt->new('0x' . $hex); 
  my @code;
  foreach (0..21) {
    push @code , $alphabet[$h % $base];
    $h->bdiv($base);
  }
  return join('', reverse(@code));
}

## File listener loop
my $sfh;
my $curtrack = 'none';
chdir($spotify_dir);
while(1) {
  open $sfh, 'guistate';
  $state = join('', <$sfh>);
  close $sfh;
  if ($state =~ /playing_track_id.:.(\w+)/) {
    my $track = base62_encode($1);
    if ($track ne $curtrack) {
      print "http://open.spotify.com/track/" . $track . "\n";
      get $announce_url . '?auth=' . $security_code . '&track=' . $track ;
      $curtrack = $track;
    }
  }
  sleep(2);
}