DhMakePerl::Utils - helper routined for dh-make-perl and alike

    use DhMakePerl::Utils qw(is_core_module);

    my $v = is_core_module('Test::More', '1.002');
    my $v = nice_perl_ver('5.010001');

package DhMakePerl::Utils;

our @EXPORT_OK = qw(
    find_core_perl_dependency
    find_cpan_module find_cpan_distribution
    is_core_module
    nice_perl_ver
    split_version_relation
);

use base Exporter;

use 5.10.0;

use Module::CoreList ();
use Debian::Dependency;

sub find_cpan_module {
    my( $name ) = @_;

    my $mod;

    # expand() returns a list of matching items when called in list
    # context, so after retrieving it, we try to match exactly what
    # the user asked for. Specially important when there are
    # different modules which only differ in case.
    #
    # This Closes: #451838
    my @mod = CPAN::Shell->expand( 'Module', '/^' . $name . '$/' );

    foreach (@mod) {
        my $file = $_->cpan_file();
        $file =~ s#.*/##;          # remove directory
        $file =~ s/(.*)-.*/$1/;    # remove version and extension
        $file =~ s/-/::/g;         # convert dashes to colons
        if ( $file eq $name ) {
            $mod = $_;
            last;
        }
    }
    $mod = shift @mod unless ($mod);

    return $mod;
}

sub find_cpan_distribution {
    my( $name ) = @_;

    $name =~ s/::/-/g;

    return CPAN::Shell->expand( 'Distribution',
        "/\\/$name-[^\\/]+\\.(tar|zip)/" );
}

sub is_core_module {
    my ( $module, $ver ) = @_;

    my $v = Module::CoreList->first_release($module, $ver);   # 5.009002

    return unless defined $v;

    $v = version->new($v);                              # v5.9.2
    ( $v = $v->normal ) =~ s/^v//;                      # "5.9.2"

    return $v;
}

sub nice_perl_ver {
    my( $v ) = @_;

    if( $v =~ /\.(\d+)$/ and $v !~ /\..+\./ ) { # do nothing for 5.9.1
        my $minor = $1;
        if( length($minor) % 3 ) {
            # right-pad with zeroes so that the number of digits after the dot
            # is a multiple of 3
            $minor .= '0' x ( 3 - length($minor) % 3 );
        }

        my $ver = 0 + substr( $minor, 0, 3 );
        if( length($minor) > 3 ) {
            $ver .= '.' . ( 0 + substr( $minor, 3 ) );
        }
        $v =~ s/\.\d+$/.$ver/;

        $v .= '.0' if $v =~ /^\d+\.\d+$/;   # force three-component version
    }

    return $v;
}

sub core_module_perls {
    my( $module, $version ) = @_;

    my @ret;

    $version = version->new($version) if $version;

    for my $v(
        sort keys %Module::CoreList::version ){

        # Module::CoreList::version includes families (i.e. "5") as well as
        # full versions, skip the families.
        next unless ($v =~ /^\d+\.\d+(?:\.|$)/);

        next unless exists $Module::CoreList::version{$v}{$module};

        my $found = $Module::CoreList::version{$v}{$module};

        push @ret, $v
            if not $version
                or $found and version->new($found) >= $version;
    }

    return @ret;
}

our %debian_perl = (
    '5.8'   => {
        min => Dpkg::Version->new('5.8.8'),
        max => Dpkg::Version->new('5.8.8'),
    },
    '5.10'  => {
        min => Dpkg::Version->new('5.10.0'),
        max => Dpkg::Version->new('5.10.1'),
    },
);

sub find_core_perl_dependency {
    my ( $module, $version ) = @_;

    if ( $module eq 'perl' ) {
        return Debian::Dependency->new('perl') unless $version;

        return Debian::Dependency->new( 'perl', nice_perl_ver($version) );
    }

    my $perl_dep;

    my @perl_releases = core_module_perls( $module, $version );

    for my $v (@perl_releases) {
        $v = nice_perl_ver($v);

        $v =~ /^(\d+\.\d+)(?:\.|$)/;
        my $major = $1 or die "[$v] is a strange version";

        # we want to avoid depending on things like 5.8.9 which aren't in
        # Debian and can contain stuff newer than in 5.10.0
        if (    $debian_perl{$major}
            and $debian_perl{$major}{max} >= $v )
        {
            return Debian::Dependency->new( 'perl', $v );
        }
    }

    # not a core module
    return undef;
}

sub split_version_relation {
    my $in = shift;

    $in =~ s/^\s*([<>=!])\s*//;

    my $rel = $1 // '>=';

    $rel = '>>' if  $rel eq '>';

    $rel = '<<' if $rel eq '<';

    return ( $rel, $in );
}

1; # End of DhMakePerl