rgtool.raku

#!/usr/bin/rakudo

use XML::XPath;
use TagLibC;

enum Format <MP3Gain>;

class Loudness {
   has Real $.dbfs is readonly;
   has Real $.db is readonly;
   has Real $.amplitude is readonly;
}

class Measurement {
   has Loudness $.integrated is readonly;
   has Loudness $.momentary is readonly;
   has Loudness $.shortterm-maximum is readonly;
   has Loudness $.sample-peak is readonly;
   has Loudness $.true-peak is readonly;
}

class Track {
   has Measurement $.measurement is readonly;
   has Str $.file is readonly;
}

sub lift_measurement(XML::Element $e) {
   my $measurements = $e.nodes.map: -> $_ {
      next unless $_ ~~ XML::Element;
      next if .name eq 'track';
      (.name, Loudness.new(|<dbfs db amplitude>.map(-> $n {$n => .attribs{$n} if .attribs{$n}}).Map>>.Real))
   };

   Measurement.new(|$measurements.Map)
}

sub MAIN(
   Bool   :o(:$terse)   = True, #= Terse output
   Str    :s(:$skiptag) = 's',  #= mp3gain compat, ignored
   Int    :d(:$target)  = 0,    #= Reference level, modify suggested gain by level, mp3gain compat, ignored
   Bool   :k(:$noclip)  = True, #= mp3gain compat, ignored presently
   Bool   :c(:$nowarn)  = True, #= mp3gain compat, ingored presently
   Format :f(:$format)  = MP3Gain, #= output format
   *@files # Files to process
) {
   my $bs1770 = run(|<bs1770gain --replaygain --track-tags --album-tags --suppress-progress --xml -imstp -->, |@files, :out);
   my $report = XML::XPath.new(xml => $bs1770.out.slurp: :close);

   my $album = lift_measurement($report.find('/bs1770gain'));
   my $tracks = $report.find('/bs1770gain/track').Array.map: -> $_ {
      Track.new(file => .attribs<file>, measurement => lift_measurement($_));
   }

   if ($format == MP3Gain) {
      # peak = sample-peak.amplitude
      #
   }
}