#!/usr/bin/perl

use strict;
use warnings;
use File::Find::Rule;
use File::Spec;

die "Usage: $0 path/to/search\n" unless ( @ARGV == 1 and -d $ARGV[0] );

my @dirs = File::Find::Rule->directory()->in( $ARGV[0] )
    or die "Can't find anything in $ARGV[0]\n";

for my $dir ( @dirs ) {
    my @mp3s = File::Find::Rule->maxdepth(1)->file()->name("*.[Mm][Pp]3")->in($dir);
    if ( @mp3s ) {
        ( my $m3u = ( File::Spec->splitdir( $dir ))[-1] ) =~ s/[\s.']+//g;
        if ( open( M3U, ">", "$dir/$m3u.m3u" )) {
            print M3U "$_\n" for ( @mp3s );
            close M3U;
            warn sprintf( "%d mp3s listed in %s\n", scalar @mp3s, "$dir/$m3u.m3u" );
        }
        else {
            warn "Unable to create $dir/$m3u.m3u : $!\n";
        }
    }
}