sub AUTOLOAD {
  our $AUTOLOAD;
  my $s = shift;
  $AUTOLOAD  =~ /.*::get(_next)*(_\w+)_files*$/ or
    croak "No such method: $AUTOLOAD";
  my ($next, $type) = ($1, $2);

  # Don't stomp on an already existing iterator
  my $last = $s->{_last_next_req};
  if ($next && $last && ($last ne $type) && @{$s->{_file_queue}{$type}}) {
    croak "File queue not empty, cannot create iterator. Aborting.";
  }
  $s->{_last_next_req} = $type if $next;

  # Don't re-fetch files if we already have files in queue
  if ($next && @{$s->{_file_queue}{$type}}) {
    return $s->get_next_file($type);
  }

  # Get the files and return appropriate file(s) based on method called
  my $attr = "${type}_files";
  my @files = @{$s->{$attr}};
  return @files if !@files || !$next;
  return $s->get_next_file($type, @files);
}

sub get_next_file {
  my $s = shift;
  my $type = shift || 'all';

  if (!$s->{_selected_file}) {
    my @files         = @_ ? @_ : $s->get_files;
    $s->{_file_queue}{$type} = \@files;
  }

  my $next_file        = shift @{$s->{_file_queue}{$type}};
  $s->{_selected_file} = $next_file;

  return $next_file;
}