getting correct versions of possible valid dependencies

gistfile1.txt

sub _get_deb_candidates {
    my ( $self, $wanted_pkgs) = @_;

    $self->log('._deb_deb_candidates')->logdie("Please provide packages to search for") unless $wanted_pkgs;

    my $candidates;

    for my $wanted_pkg (keys %{$wanted_pkgs}) {
        my $pkg_pattern = $self->_get_pkg_alternatives_pattern($wanted_pkg);

        my $packages = $self->dpkg->get_available_versions($pkg_pattern);
        my $versions = { map { my $pkg_name = $_; map { $_ => $pkg_name } keys %{ $packages->{$pkg_name} || {} } } keys %{ $packages || {} } };

        my $version_has_epoch = 0;

        for my $version (keys %{$versions}) {
            # If we found a version with epoch
            if ($version =~ m{ \A (\d+): }gmx) {
                # and the epoch is bigger than what we already have found, let's store it
                $version_has_epoch = $1 if ($1 > $version_has_epoch);
            }
        }
        my $wanted_version = $wanted_pkgs->{$wanted_pkg} || 0;
        # Add epoch to wanted version if existing packages has started using epoch
        if ($wanted_version && $version_has_epoch) {
            # replace existing epoch, or prepend it.
            if ($wanted_version =~ m{ \A (\d+): }gmx) {
                if ($1 < $version_has_epoch) {
                    $wanted_version =~ s{ \A (\d+): }{$version_has_epoch}gmx;
                }
            } else {
                $wanted_version = "$version_has_epoch:$wanted_version";
            }
        }

        $candidates->{$wanted_pkg} = {
            wanted_version   => $wanted_version,
            pkg_pattern      => $pkg_pattern,
            versions         => { map {
                $_ => {
                    wanted_version       => $wanted_version,
                    version              => $_,
                    pkg_name_version     => $versions->{$_} . ($wanted_version ? " (>= $wanted_version)" : ''),
                    apt_get_install_line => $versions->{$_} . ($wanted_version ? "=$_" : ''),
                }
            } grep { $_ ne '(null)' } keys %{$versions} },
        };
    }

    return $candidates;
}