#!/usr/bin/perl

use Audio::FLAC::Header;
use utf8;
use strict;

my ($f, @files);
my @fields = qw/Title Artist Album Date Comment Genre Tracknumber/;

# config/defaults
my %config = (
	rename => 1,
	artist => 0,
);

# process args
A: while ($f = shift @ARGV) {

	if (-f $f ) { push @files, $f; next}

	for (@fields) {
		if ($f =~ /^\-\-no\-$_/i) {
			$config{skip}{$_} = 1;
			next A;
		} elsif ($f =~ /^\-\-$_/i) {
			$config{default}{$_} = shift @ARGV;
			next A;
		}
	}

	if ($f eq '--no-rename') {
		$config{rename} = 0;
		next;
	}
	if ($f eq '--with-artist') {
		$config{artist} = 1;
		next;
	}

	die "Unknown tag/no file $f";
}

for (@files) {
	edit_tag($_);
}

sub mk_utf8 {
        my $x = shift;
       # utf8::upgrade($x);
        return $x;
}

sub rationalise_strings {
	my $str = shift;
	print "$str\n";
	$str =~s/&/and/og;
	$str =~s/[ \:\/]/_/og;
	$str =~s/[^\w\-\_]//og;
	$str =~s/_+-+_+/-/og;
	$str =~s/__+/_/og;
	$str = ucfirst(lc($str));

	return $str;
}

sub rationalise_fields {
	my $f = shift;
	$f=~y/A-Z/a-z/;
	return ucfirst($f);
}

sub edit_tag {
	my $file = shift;
	my ($f, $ftag, $flac, $src, $song, $artist, $newtag, $changed, $skip);

	print "$file:\n";
	if (index($file,'/')>-1) {
		($src = $file) =~ s|[^/]+$||;
	} else {
		$src = '';
	}

	$flac = Audio::FLAC::Header->new($file);
	die "Can't get FLAC header - $!" unless $flac;

	$ftag = $flac->tags();
	die "Can't get flac tags - $!" unless $ftag;

	$changed = 0;

	for $f (@fields) {
		$skip	= exists $config{skip}{$f} ? 1 : 0;
		print "\t[$f] ";
		if ($config{default}{$f} || '') {
			print "$config{default}{$f}\n";
			$$ftag{$f} = mk_utf8($config{default}{$f});
			$changed = 1;
			next;
		}
		$f	= ((grep /^$f$/i,keys %$ftag)[0] || $f);
		if (! length($$ftag{$f} || '')) {

			print '("") ';

			if ($skip ) {
				$newtag = ''; print "\n";
			} else {
				print '---> ';
				$newtag = <>;
			}
			chop($newtag);
			if ($newtag =~/\w+/) {
				$$ftag{$f} = mk_utf8($newtag);
				$changed = 1;
			}
		} else { print "$$ftag{$f}\n"; }
		#$$f{ucfirst(lc($_))} = $$m{$_}
		$$ftag{rationalise_fields($f)} = delete $$ftag{$f};
	}

	if ($changed) {
		print "*** NEW TAG WRITTEN ***\n";
		$flac->write() || warn $!;
	}

	$song = $$ftag{Title} || $$ftag{(grep /^Title$/i,keys %$ftag)[0]};
	$artist = $$ftag{Artist} || $$ftag{(grep /^Artist$/i,keys %$ftag)[0]};

	$song = rationalise_strings($song) . '.flac';
	if ($config{'artist'}) {
		$song = rationalise_strings($artist) . '-' . $song;
		print ".\n";
	}
	$song = $src . $song;

	if ($config{rename}) {
		if ($file ne $song && ! -e $song) {
			print "$file -> $song";
			rename $file, $song;
		} else { print "$song exists; not renaming\n"; }
	} else { print "No-rename requested\n"; }
		
	print "\n";
}