#!/usr/bin/perl

use 5.14.0;

use strict;

use warnings;

use File::Copy qw(move);

use File::Basename qw(basename dirname);

use File::Path qw(make_path);

#my $library = "/home/sir/Music/Songbird Music";

my $library = "/home/sir/Music/Songbird Music";

my (%t, %files, @files, @dirs, @wrong_case);

my $flac_version = '1.2.1';

getdirs($library);

foreach my $dn (sort(@dirs)) {

	#my $ino = (stat($fn))[1];

	#say "$dn has $ino";

	undef %files;

	undef @files;

	getfiles($dn);

	my $fc = @files;

	if ($fc > 0) {

		replaygain($dn);

		for (my $n = 0; $n < $fc; $n++) {

			my $fn = $files[$n];

			undef(%t);

			foreach my $tag (keys($files{$fn})) {

				$t{$tag} = $files{$fn}{$tag}->[0];

				#say "$tag = $t{$tag}";

			}

			vendor($fn);

			rmtag($fn, 'rating');

			albumartist($fn, $fc);

			track($fn);

			spaces($fn);

			totaltracks($fn, $fc);

	#		empty($fn);

			duplicate($fn);

			discnum($fn, $n, $fc);

		}

	}

}

# Make this subroutine and the whole script so that each file name is stored in a hash and that each member contains an anonymous hash with the tags (the alltags hash).

# This means it won't have to look up the tags again for the albumartist subroutine.

sub gettags {

	my $fn = shift;

	my (%alltags, @mflac);

	open(OUTPUT, '-|', 'metaflac', '--no-utf8-convert', '--show-vendor-tag', '--export-tags-to=-', $fn) || die "can't run metaflac: $!";

	chomp(@mflac = (<OUTPUT>));

	foreach (@mflac) {

		my (@tag, $tagname);

		if (/^reference/) {

			@tag = split(' ');

			$tagname = 'vendor_ref';

			$tag[1] = $tag[2];

		} else {

			@tag = split('=');

			$tagname = lc($tag[0]) or next;

		}

		if ($tag[1]) {

			push(@{$alltags{$tagname}}, $tag[1]); }

			else { push(@{$alltags{$tagname}}, 'null'); }

	}

	close(OUTPUT) || die "couldn't close metaflac: $!";

	return %alltags;

}

sub vendor {

	my $fn = shift;

	if ($t{vendor_ref} ne $flac_version) {

		my $newfn = $fn . '.' . int(rand(10000));

		say "$fn: old encoder ($t{vendor_ref}), re-encoding...";

		if ($? == 0) {

			move($newfn, $fn) or die "Couldn't rename '$newfn': $!";

		} elsif ($? == 2) {

			say "Interrupted by user!";

			unlink($newfn) if (-f $newfn);

			exit;

		}

	}

}

sub getdirs {

	my $dn = shift;

	open(FIND, '-|', 'find', $dn, '-name', '*', '-type', 'd')

	or die "Can't run 'find': $!";

	chomp(@dirs = (<FIND>));

	close(FIND) or die "Can't close 'find': $!";

}

sub getfiles {

	my $dn = shift;

	my $fn;

	opendir(my $dh, $dn) or die "Can't open directory '$dn': $!";

	foreach (readdir $dh) {

		$fn = $dn . '/' . $_;

		if (/.flac$/ && -f $fn) {

			push(@files, $fn);

			$files{$fn} = { gettags($fn) };

		}

	}

	closedir $dh or die "Can't close directory '$dn': $!";

}

sub replaygain {

	my $dn = shift;

	my %replaygain;

	#foreach ('REFERENCE_LOUDNESS', 'TRACK_GAIN', 'TRACK_PEAK', 'ALBUM_GAIN', 'ALBUM_PEAK') {

	#	my $tag = 'REPLAYGAIN_' . $_;

	#	system('metaflac', '--remove-tag=' . $tag, keys(%files));

	#}

	foreach my $fn (sort(keys %files)) {

			if ($files{$fn}{replaygain_album_gain}) {

				$replaygain{$files{$fn}{replaygain_album_gain}->[0]}++;

			}

	}

	if (keys(%replaygain) != 1) {

		print "$dn: adding ReplayGain...";

		system('metaflac', '--add-replay-gain', keys(%files));

		say " done";

	}

}

sub albumartist {

	my $fn = shift;

	my $tracks = shift;

	if (! $t{albumartist} || $t{albumartist} eq 'null') {

		my %artist;

		my $max;

		if ($tracks == 1) { $max = $tracks } else { $max = $tracks / 2 }

		foreach my $fn (sort(keys(%files))) {

			$artist{$t{artist}} = 1;

		}

		if (keys(%artist) > $max) {

			$t{albumartist} = 'Various Artists';

		} else { $t{albumartist} = $t{artist} };

		say "$fn: adding albumartist tag";

		system('metaflac', '--remove-tag=ALBUMARTIST', "--set-tag=ALBUMARTIST=$t{albumartist}", $fn);

	}

}

sub empty {

	my $fn = shift;

	foreach my $tag (sort(keys(%{$files{$fn}}))) {

		foreach (@{$files{$fn}{$tag}}) {

			if ($_ eq 'null') {

				say "$fn: WARNING: empty $tag tag";

			}

		}

	}

}

sub duplicate {

		my $fn = shift;

		my %exists;

		foreach my $field (sort(keys(%{$files{$fn}}))) {

			foreach my $tag (@{$files{$fn}{$field}}) {

				if ($exists{$field} && $exists{$field} eq $tag) {

					say "$fn: removing duplicate $field tag";

					system('metaflac', "--remove-tag=${field}", "--set-tag=${field}=${tag}", $fn);

				} else {

					$exists{$field} = $tag;

				}

			}

		}

}

sub track {

	my $fn = shift;

	if (!$t{tracknumber}) {

		say "$fn: doesn't have any tracknumber tag"

	}

	elsif ($t{tracknumber} =~ m/^0/ && $t{tracknumber} != 0) {

		say "$fn: fixing tracknumber tag";

		$t{tracknumber} =~ s/^0+//;

		system('metaflac', '--remove-tag=TRACKNUMBER', "--set-tag=TRACKNUMBER=$t{tracknumber}", $fn);

	}

}

sub spaces {

	my $fn = shift;

	my %temp;

	foreach my $tag (sort(keys(%t))) {

		$temp{$tag} = $t{$tag};

		$temp{$tag} =~ s/(^\s*)|(\s*$)//g;

	}

	foreach my $tag (sort(keys(%t))) {

		if ($temp{$tag} ne $t{$tag} && "$temp{$tag}") {

			say "$fn: removing leading and trailing whitespaces from tags";

			#say $temp{$tag};

			my $ufield = uc($tag);

			system('metaflac', "--remove-tag=$ufield", "--set-tag=${ufield}=${temp{$tag}}", $fn);

		}

	}

}

sub totaltracks {

	my $fn = shift;

	my $tracks = shift;

	if (

	!$t{totaltracks} &&

	!$t{tracktotal}

	) {

		say "$fn: adding totaltracks tag";

		system('metaflac', "--set-tag=TOTALTRACKS=$tracks", $fn);

	}

	elsif (

	$t{tracktotal} &&

	!$t{totaltracks}

	) {

		say "$fn: replacing tracktotal tag with totaltracks";

		system('metaflac', '--remove-tag=TRACKTOTAL', "--set-tag=TOTALTRACKS=$t{tracktotal}", $fn);

	}

}

sub discnum {

	my $fn = shift;

	my $n = shift;

	my $fc = shift;

	my $dn = dirname($fn);

	my ($match, $newfn);

	my $regex = '[[:punct:]]?(cd|disc) ?[0-9]+[[:punct:]]?$';

	if ($t{album} =~ /$regex/i) {

		$t{album} =~ s/.?(${^MATCH}).?//;

		system('metaflac', '--remove-tag=ALBUM', "--set-tag=ALBUM=$t{album}", $fn);

	}

	if (!$t{discnumber}) {

		if (basename($fn) =~ /^[0-9]+-/) {

			$match = ${^MATCH};

			${^MATCH} =~ /([0-9]+)/;

			$t{discnumber} = eval { $1 =~ s/^0+//; };

		}

		elsif ($dn =~ /$regex/i) {

			$match = ${^MATCH};

			${^MATCH} =~ /([0-9]+)/;

			$t{discnumber} = eval { $1 =~ s/^0+//; };

			$dn =~ s/ .?($match).?//;

			make_path($dn) if (! -d $dn);

			$newfn = "${dn}/" . $t{discnumber} . '-' . basename($fn);

			unless (-f $newfn) {

				move($fn, $newfn) or die "Couldn't rename '$fn': $!";

			}

		}

		else {

			$t{discnumber} = 1;

			$newfn = "${dn}/" . $t{discnumber} . '-' . basename($fn);

			unless (-f $newfn) {

				move($fn, $newfn) or die "Couldn't rename '$fn': $!";

			}

		}

		if (!$newfn) { $newfn = $fn }

		say "$newfn: adding discnumber tag";

		system('metaflac', "--set-tag=DISCNUMBER=$t{discnumber}", $newfn);

	}

}

sub rmtag {

	my $fn = shift;

	foreach my $field (@_) {

		if ($t{$field}) {

			say "$fn: removing $field tag";

			system('metaflac', "--remove-tag=${field}", $fn);

		}

	}

}