=pod

=head1 NAME

iPod-backup: reclaim tracks orphaned on an iPod 

=head1 SYNOPSIS

    perl ipod-backup.pl -do MODE -out DIR -mnt DRIVE [-top DIR]

    -out    Output directory for any reclaimed files
    -mnt    iPod mount path or drive
    -top    iTunes top-level directory
    -do     perform one of the following operations:

            stat    print iPod vs iTunes statistics (default)
            sync    reclaimed tracks not in iTunes
            bak     backup full iPod

=head1 DISCUSSION

Man, dont even get me started on a rant about Apple software...

When disk files are lost, iTunes helpfully does nothing then silently 
removes them from your iPod next time you plug it in. While the latter
+ 
can be avoided by disabling automatic sync'ing, there is no way to 
import tracks on the iPod back into iTunes...ho hum

This script checks your iPod's database against iTune's and imports an
+y 
tracks not available in iTunes back onto the harddisk.

It can also do a full backup of the iPod in a human friendly manner, i
+e:

    /Artist/Album/Track

rather than Apple's quirky 

    /F<DIGITS>/<ARBITRARY TRUNCATED FILENAME>

=head1 BUGS & CAVEATS

This is quick and dirty programming...use at your own risk.

In particular, the iPod database is a binary format. Rather than caref
+ully 
reverse engineer by hand, I just weild the Swiss Army Chainsaw and hac
+k off 
what I dont need. Your mileage may vary, as they say.

Only tested on Windows XP. Linux requires 2.6 kernel or a FAT32 format
+ted 
iPod. You would probably be better off looking at Gnupod for that.

=cut


use strict;
use utf8;

usage() if @ARGV % 2;

my %ARGS  = @ARGV;
my @KEYS  = (undef, "Name", "Path", "Album", "Artist", "Genre", "Kind"
+, undef, "Comments");
my $TYPE  = qr/\.(?:mp3|aux)/i; 
my @STAT  = ("sync'd","iPod","iTunes");
my $IPOD  =  1;
my $SYNC  =  0;
my $DISK  = -1;

my $mode          = $ARGS{-do}  || "stat";
my $ipod_temp     = $ARGS{-out} || "./ipod-temp";
my $ipod_mount    = $ARGS{-mnt} || usage();
my $itunes_root   = $ARGS{-top};

my $ipod_itunesdb = "$ipod_mount/iPod_Control/iTunes/iTunesDB";
my $ipod_sysinfo  = "$ipod_mount/iPod_Control/Device/SysInfo";
my $ipod_music    = "$ipod_mount/iPod_Control/Music";
my $itunes_lib    = "$itunes_root/iTunes Music Library.xml";
my $itunes_music  = "$itunes_root/iTunes Music";

die "'$ipod_itunesdb' does not exist\n"     unless -f $ipod_itunesdb;
die "'$itunes_root' is not a directory\n"   unless !$itunes_root || -d
+ $itunes_root;
die "'$itunes_lib' does not exist\n"        unless !$itunes_root || -f
+ $itunes_lib;

if($mode eq "stat"){
    stat_ipod($ipod_itunesdb, $itunes_lib);
}
elsif($mode eq "bak"){
    import_ipod($ipod_temp, $ipod_itunesdb);
}
elsif($mode eq "sync"){
    import_ipod($ipod_temp, $ipod_itunesdb, $itunes_lib);
}
else{
    usage();
}

#
#
#
sub usage
{
    my $src = fslurp( fopen($0) );
    print "\n", $1,"\n\n",$2,"\n\n"
        if $src =~ /=head1 NAME\s*?(.*?)\s*?=head1 SYNOPSIS\s*?(.*?)\s
+*?=head1 DISCUSSION/s;
    exit 0;
}

#
# Print shared and unique tracks on iPod and iTunes
#
sub stat_ipod
{
    my $ipod  = shift || die "Error: No path to iTunesDB\n";
    my $local = shift || die "Error: No path to XML library\n";
    my $dup   = {};
    my ($disk, $pod, $syn);

    $ipod  = parse_itunesdb($ipod);
    $local = parse_itunes_library($local);

    $dup->{ $_->{Artist}." - ".$_->{Album}." - ".$_->{Name} }++ foreac
+h @$ipod;
    $dup->{ $_->{Artist}." - ".$_->{Album}." - ".$_->{Name} }-- foreac
+h @$local;

    foreach(sort keys %$dup){
        my $s = $dup->{$_};
        printf "%-70s %-6s\n", (length $_ < 70) ? $_ : substr($_,0,67)
+."...", $STAT[$s];
        ($s == $DISK) ? $disk :
        ($s == $IPOD) ? $pod : $syn += 1;
    }

    my $format = "%-6s: %5d / %-5d\n";
    print "\n\n";
    printf $format, "iPod",  $pod,  scalar(@$ipod);
    printf $format, "iTunes",$disk, scalar(@$local);
    printf $format, "Sync'd",$syn,  scalar(@$ipod)+scalar(@$local);
}

#
# Import tracks on an iPod
# If $local is provided, only imports those not currently in iTunes
# else, imports the lot for backup
#
sub import_ipod
{
    my $dir   = shift || "./ipod-temp";
    my $ipod  = shift || die "Error: No path to iTunesDB\n";
    my $local = shift;

    my $dup   = {};
    my @err   = ();
    my $prog  = 0;
    my $totl  = 0;

    $ipod  = parse_itunesdb($ipod);
    $local = parse_itunes_library($local) if $local;
    $local = [] unless $local;

    print "(ipod)  scanned tracks: ",scalar(@$ipod),"\n";
    print "(local) scanned tracks: ",scalar(@$local),"\n";

    $dup->{ $_->{Artist}."/".$_->{Album}."/".$_->{Name} } = $_    fore
+ach @$ipod;
    $dup->{ $_->{Artist}."/".$_->{Album}."/".$_->{Name} } = undef fore
+ach @$local;
    (defined $dup->{$_}) ? $totl++ : delete $dup->{$_} foreach(keys %$
+dup);

    mkdir($dir) unless -d $dir;

    $|++;
    foreach(sort keys %$dup)
    {
        my $track = $dup->{$_} or next;
        my $path  = $track->{Path};
        my $ext   = $1 if $track->{Path} =~ /\.(\S+)$/;

        my $in    = "$ipod_mount$track->{Path}";
        my $d1    = "$dir/$track->{Artist}";
        my $d2    = "$d1/$track->{Album}";
        my $out   = "$d2/$track->{Name}.$ext";

        my $ui    = $track->{Artist}." - ".$track->{Album}." - ".$trac
+k->{Name};

        mkdir($d1) unless -d $d1;
        mkdir($d2) unless -d $d2;

        printf "%-11s %-65s", ++$prog."/".$totl, 
               (length($ui) < 60) ? $ui : substr($ui,0,60)."...";

        $@ ='';
        eval{
            fcopy($in, $out) unless( -f $out && (stat($in))[7] == (sta
+t($out))[7] );
            print "ok\n";
        };
        if($@)
        {
            push @err, "$out: $@";
            print "--\n";
        }
    }

    print STDERR "\nErrors:\n";
    print @err ? join('\n', @err) : "none", "\n";
}

#
# BRRRRRRRR!-BRRRRRRR!
#
sub parse_itunesdb
{
    my $f = fopen(shift);
    my $s = fslurp($f);
    my $fields;

    my @records = ();
    my $record  = {};

    foreach( split(/mhod/, $s) )
    {
        my ($eor, $t, $k);
        next unless length $_;

        s/\000\000+/ /sgo;
        s/\000//sgo;

        # this doesnt work...???
        # s/^(..(.).(.).....)//;
        # $c = escape($1);
        # $l = chr($2);
        # $t = $K[ord($3)];

        $t = substr($_, 0, 10);
        $t = $KEYS[ord(substr($t, 4, 5))];
        $_ = substr($_, 10, length $_);        

        next if !$t;

        if($t eq "Path")
        {
            $eor++; 
            $_ = $1 if m/^(.*?$TYPE)/;
            $_ =~ s/:/\//sg;
        }

        # TODO: Some final checks for non-printable pathnames...

        $record->{$t} = $_ ;
        if($eor)
        {
            $record->{Artist} = "Unknown"  unless defined $record->{Ar
+tist};
            $record->{Album}  = "Unknown"  unless defined $record->{Al
+bum};
            push @records, $record         if     defined $record->{Na
+me};
            $record = {};
        }
    }
    return \@records;
}

#
# YAHRXP...
#
sub parse_itunes_library
{
    my $lib = fopen(shift);
    my $ok  = 0;

    my @records = ();
    my $record  = {};

    while(<$lib>)
    {
        chomp;
        last  if m/^\s*?<key>Playlists<\/key>/;
        $ok++ if m/^\s*?<key>Tracks<\/key>/;
        next unless $ok;

        if(m/^\s*?<key>(.*?)<\/key><(\S+)>(.*?)<\/\2>/)
        {
            $record->{$1} = xml_decode($3) ;
        }
        elsif(m/^\s*?<key>(\d+)<\/key>/)
        {
            $record->{Artist} = "Unknown"  unless defined $record->{Ar
+tist};
            $record->{Album}  = "Unknown"  unless defined $record->{Al
+bum};
            push @records, $record         if     defined $record->{Na
+me};
            $record = {};
        }
    }
    return \@records;
}

#
# decode filename urls in XML
#
sub url_decode 
{
    my $str = shift;
    $str =~ tr/+/ /;
    $str =~ s/%(..)/pack("C",hex($1))/eg;
    return $str;
}

#
# TODO: decode XML-entities in fields
#
sub xml_decode 
{
    my $str = shift;
    $str =~ s/\&\#(\d+)\;/chr($1)/esg;
    return $str;
}

#
#
#
sub fcopy
{
    my $in  = shift;
    my $out = shift;
    my $buf = shift || 1024;
    my $fin  = fopen($in);
    my $fout = fopen(">".$out);
    my ($b, $r, $w);
    
    while($r = sysread($fin, $b, $buf))
    {
        $w = syswrite($fout, $b, $r);
        last if $r < $buf;
    }
}

#
#
#
sub fopen
{
    my $path = shift or die "fopen: no path\n";
    my $f;
    open $f,$path or die "$path: $!";
    binmode $f;
    return  $f;
}

#
#
#
sub fslurp
{
    my $f    = shift;
    local $/ = undef;
    return <$f>;
}