#!/usr/bin/perl -w
use strict;
use Cwd;
use File::Spec::Functions qw(catdir catfile);
use File::Copy;
use MP3::Info;

die "usage: $0 dirname [dirname ...]\n" unless @ARGV;

my $cwd = cwd();

my %skip;

for(@ARGV) {
    chdir($_) or (warn("Couldn't chdir to $_\n"), next);

    opendir my($dh), ".";
    for my $file (grep /\.mp3\z/i and -f, readdir $dh) {
        my ($artist, $title) = @{ get_mp3tag($file) }{qw(ARTIST TITLE)};
        next unless $artist and $song;

        my $dirname = lc $artist;

        s/\bthe\s*//g, s/^\s+//g, s/\s+$//g, tr/ /_/ for $dirname;
    
        my $targ_dir = catdir("..", $dirname);

        unless($skip{$directory} or -e $targ_dir) {
            print "Create $dirname folder (y/n)? ";
            <STDIN> =~ /^y/i ? mkdir $targ_dir : undef $skip{$directory};
        }
    
        if(-d $targ_dir) {
            my $target = catfile($targ_dir, "$artist - $title.mp3");
            print "$file -> $target\n";
            move($file, $target);
        }
        else {
            warn(
                "Skipping $file, $directory ",
                (-e $targ_dir ?
                    "is not a directory"
                    : "was not created"
                ),
                ".\n"
            );
        }
    }

    chdir($cwd);
}