use strict;
use warnings;
no warnings 'uninitialized';

use XML::Rules;

my %written;
my %depends;
my $parser = XML::Rules->new(
	style => 'filter',
	rules => {
		_default => 'raw',
		'name,members' => 'raw extended',
		'Group' => 'raw extended array',
		record => sub {
			my @I_depend;
			if (exists $_[1]->{':members'} and exists $_[1]->{':members'}{':Group'}) {
				@I_depend = grep !exists $written{$_}, map $_->{_content}, @{$_[1]->{':members'}{':Group'}};
			}
			if (@I_depend) {
				$_[1]->{':I_depend'} = {map {$_ => 1} @I_depend};
				foreach (@I_depend) {
					push @{$depends{$_}}, $_[1]
				}
				return;
			} else {
				my $name = $_[1]->{':name'}{_content};
				$written{$name} = 1;
				my @to_write = $_[1];
				if (exists $depends{$name}) {
					push @to_write, find_dependent($name);
				}
				return 'record' => \@to_write;
			}
		}
	}
);

sub find_dependent {
	my $name = shift;
	my @to_write;
	foreach my $parent (@{$depends{$name}}) {
		delete $parent->{':I_depend'}{$name};
		if (! %{$parent->{':I_depend'}}) { # if it doesn't depend on anything more
			push @to_write, $parent;
			push @to_write, find_dependent($parent->{':name'}{_content});
		}
	}
	delete $depends{$name};
	return @to_write;
}

$parser->filter(\*DATA);

if (%depends) {
	print STDERR "Unsatisfied dependencies! Some records depend on these unknown groups: ",
		join ", ", keys %depends;
}