use strict;

my ($d) = @ARGV;
$d = './' unless $d;

my @l= ();
die unless opendir(my $h, $d);
foreach(readdir $h)
{ next if /^\.+$/;
  push @l, $_ if /\.mp3$/i;
}
closedir $h;

my $c = 0;
foreach my $f (@l)
{  
  next unless open my $h, "<$d/$f";
  binmode $h;
  read $h, my $t, 3;
  my($a,$n) = ('','');

  if($t eq 'ID3')
  { read $h, $t, 1000;
  if($t =~ /TIT2...(.)...(.*)/s)
  { $n = substr $2, 0, -1+ord $1;
  }
  if($t =~ /TPE1...(.)...(.*)/s)
  { $a = substr $2, 0, -1+ord $1;
  }
  }
  else
  { seek $h, -128, 2;
  read $h, $t, 3;
  if($t eq 'TAG')
  { read $h, $t, 128;
  ($n,$a) = unpack "a30a30", $t;
  }
  }
  close $h;
  $n =~ s/[\0\s\r\n]+$//s;
  $a =~ s/[\0\s\r\n]+$//s;

  next if $a eq '';
  next if $n eq '';

  my $r = "$a - $n";

  $r =~ s/http:\/\///ig;

  $r =~ s/[\0-\39]//g;
  $r =~ s/[\\\/\:\*\?\"\<\>\|]/_/g;

  while($r =~ /\s\s/) { $r =~ s/\s\s/ /; }

  my $s = $r;
  $s =~ tr/\300-\377\260\261/\200-\257\340-\357\360\361/;
  printf "%s\n", $s;

  $r .= '.mp3';

  next if $r eq $f;

  while(-e "$d/$r") { $r =~ s/\.mp3$/_\.mp3/; }

  if(rename "$d/$f", "$d/$r") { $c++; }
  else { print "$f $!\n"; }
}
printf "renamed %d of %d\n", $c, scalar @l;