#!/usr/bin/perl

use strict;
use warnings;

use MP3::Tag;
use File::Find;

File::Find::find( \&wanted, '.' );

{
	my $cover;
	my @mp3;

	sub wanted
	{
		for ($File::Find::name)
		{
			-d && do {
				undef $cover;
				last;
			};

			/\.(jpg|gif)$/ && do {
				$cover = [ $_, "image/$1" ];

				if ( @mp3 )
				{
					add_cover( $_, $cover ) for @mp3;
					@mp3 = ();
				} # if

				last;
			};

			/\.mp3$/ && do {
				$cover ? add_cover( $_, $cover )
				       : push @mp3, $_;
				last;
			};
		} # for
	} # wanted
}

sub add_cover
{
	my( $file, $cover ) = @_;

	my $mp3 = MP3::Tag->new( $file );

	$mp3->get_tags;

	my $id3v2 = exists $mp3->{'ID3v2'}
			? $mp3->{'ID3v2'}
			: $mp3->new_tag('ID3v2');

	open( my $in, '<', $cover->[0] )
		or die "Cannot open file '$cover->[0]': $!";

		binmode( $in );

		my $data = do{ local $/=undef; <$in> };

		unless ( $id3v2->get_frame('APIC') )
		{
			$id3v2->add_frame( 'APIC', $cover->[1], 3, 'Cover Image', $data );
		} # unless
		else
		{
			$id3v2->change_frame( 'APIC', $cover->[1], 3, 'Cover Image', $data );
		} # else

		$id3v2->write_tag;

	close( $in );

	$mp3->close;
} # add_cover