#!/usr/bin/perl

use 5.14.0;

use strict;

use warnings;

#use File::Find qw(finddepth);

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 (%files, @files, @dirs);

my $flac_version = '1.2.1';

getdirs($library);

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

		chomp(my $ls = `ls "$dn"/*.flac 2> /dev/null | head -n 1`);

		if (-f $ls) {

	#		my @stat = stat($dn);

	#		my $ino = $stat[1];

	#		say "$dn has $ino";

			undef %files;

			undef @files;

			getfiles($dn);

			my $fc = scalar(@files);

			if ($fc > 0) {

				#replaygain($dn);

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

					my $fn = $files[$n];

					vendor($fn);

					rmtag($fn, 'rating');

					albumartist($fn, $fc);

					track($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 = quotemeta(shift);

	my (%alltags, @mflac);

	open(OUTPUT, '-|', qq{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 say $fn;

		}

		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;

	my $vendor_ref = $files{$fn}{vendor_ref}->[0];

	if ($vendor_ref ne $flac_version) {

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

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

		system('flac', '--silent', '-8', $fn, "--output-name=$newfn");

		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, '-|', qq(find -L "$dn" -name "*" -type d))

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

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

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

	#@dirs = `find -L "$dn" -name "*" -type d -mindepth 1`;

}

sub getfiles {

	my $dn = shift;

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

	foreach (readdir $dh) {

		my $fn = "$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 (!$files{$fn}{albumartist}) {

		my $albumartist = $files{$fn}{artist}->[0];

		my %artist;

		my $max;

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

		foreach my $fn (keys %files) { $artist{$files{$fn}{artist}->[0]}++ }

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

			$albumartist = 'Various Artists';

		}

		say "$fn: adding albumartist tag";

		system('metaflac', "--set-tag=ALBUMARTIST=$albumartist", $fn);

	}

}

sub empty {

	my $fn = shift;

	foreach my $k (keys %{$files{$fn}}) {

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

			if ($_ eq 'null') {

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

			}

		}

	}

}

sub duplicate {

	my $fn = shift;

	my %exists;

	foreach my $k (keys %{$files{$fn}}) {

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

			my $tag = quotemeta($k . '=' . $_);

			if ($exists{$tag}) {

				say "$fn: WARNING: duplicate $k tag";

			} else {

				$exists{$tag} = 1;

			}

		}

	}

}

sub track {

	my $fn = shift;

	my $track = $files{$fn}{tracknumber}->[0];

	if (!$track) {

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

	}

	elsif ($track =~ m/^0/ && $track != 0) {

		say "$fn: fixing tracknumber tag";

		$track =~ s/^0+//;

		system('metaflac', '--remove-tag=TRACKNUMBER', "--set-tag=TRACKNUMBER=$track", $fn);

	}

}

sub totaltracks {

	my $fn = shift;

	my $tracks = shift;

	if (

	!$files{$fn}{totaltracks} &&

	!$files{$fn}{tracktotal}

	) {

		say "$fn: adding totaltracks tag";

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

	}

	elsif (

	$files{$fn}{tracktotal} &&

	!$files{$fn}{totaltracks}

	) {

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

		system('metaflac', '--remove-tag=TRACKTOTAL', "--set-tag=TOTALTRACKS=$files{$fn}{tracktotal}->[0]", $fn);

	}

}

sub discnum {

	my $fn = shift;

	my $n = shift;

	my $fc = shift;

	my $dn = dirname($fn);

	my $discnumber = $files{$fn}{discnumber}->[0];

	my $album = $files{$fn}{album}->[0];

	my ($match, $newfn);

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

		system('metaflac', '--remove-tag=ALBUM', $fn);

		system('metaflac', "--set-tag=ALBUM=$album", $fn);

	}

	if (!$discnumber) {

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

			$match = ${^MATCH};

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

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

		}

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

			$match = ${^MATCH};

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

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

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

			$newfn = "${dn}/" . "${discnumber}-" . basename($fn);

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

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

		}

		else {

			$discnumber = 1;

			$newfn = "${dn}/" . "${discnumber}-" . basename($fn);

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

		}

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

		say "$newfn: adding discnumber tag";

		system('metaflac', "--set-tag=DISCNUMBER=$discnumber", $newfn);

	}

}

sub rmtag {

	my $fn = shift;

	foreach my $tag (@_) {

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

			say "$fn: removing $tag tag";

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

		}

	}

}