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;