-my $data = from_json($source, {
- allow_singlequote => 1,
- allow_barekey => 1,
-});
-my $update = eval { stat(${^LAST_FH} // $ARGV)->mtime }
- or warn "Could not determine input time\n";
-$data->{-date} = Time::Piece->new($update)->datetime;
+for my $feature (values %{ $data->{data} }) {
+ while (my ($attr, $row) = each %{$feature}) {
+ delete $feature->{$attr} if ref $row eq '' and $row eq '';
+ }
+}
+
+while (my ($agent, $row) = each %{ $data->{agents} }) {
+ delete $row->{usage_global};
+ delete $row->{prefix_exceptions}; # duplicate of version_list->prefix
+ $row->{versions} = [ uniq map { $_->{version} } @{ $row->{version_list} } ];
+
+ # convert metadata list into (cleaned) lookup table
+ my %version_lookup;
+ for (@{ $row->{version_list} }) {
+ delete $_->{era};
+ delete $_->{prefix} unless $_->{prefix};
+ $version_lookup{ delete $_->{version} } = $_;
+ }
+ $row->{version_list} = \%version_lookup;
+
+ # omit identical values from subsequent versions
+ for my $feature (values %{ $data->{data} }) {
+ my $cmp; # same value to be omitted
+ my $verstats = $feature->{stats}->{$agent};
+ for my $version (@{ $row->{versions} }) {
+ defined $verstats->{$version}
+ or warn "missing feature $feature->{title} for $agent $version";
+ if (defined $cmp and $verstats->{$version} eq $cmp) {
+ delete $verstats->{$version};
+ }
+ else {
+ $cmp = $verstats->{$version};
+ }
+ }
+ }
+}