=head1 NAME

Debian::Control::FromCPAN - fill F<debian/control> from unpacked CPAN distribution

=head1 SYNOPSIS

    my $c = Debian::Control::FromCPAN->new();
    $c->discover_dependencies( { ... } );
    $c->prune_perl_deps;

    Debian::Control::FromCPAN inherits from L<Debian::Control>.
=cut

package Debian::Control::FromCPAN;

use strict;
use warnings;

our $VERSION = '0.123';

use Carp qw(croak);

use base 'Debian::Control';

use CPAN ();
use DhMakePerl::Utils qw( is_core_module find_cpan_module nice_perl_ver
  split_version_relation apt_cache is_core_perl_package );
use File::Spec qw( catfile );
use Module::Depends ();

use constant oldstable_perl_version => '5.14.2';

# Temporarily disable the warning until dpkg 1.20.x, as our usage is correct.
no if $Dpkg::Version::VERSION ge '1.02',
   warnings => qw(Dpkg::Version::semantic_change::overload::bool);

=head1 METHODS

=over

=item discover_dependencies( [ { options hash } ] )

Discovers module dependencies and fills the dependency fields in
F<debian/control> accordingly.

Options:

=over

=item apt_contents

An instance of L<Debian::AptContents> to be used when locating to which package
a required module belongs.

=item dpkg_available

An instance of L<Dpkg::Index> to be used when checking whether
the locally available package is the required version. For example:

    my $available = Dpkg::Index->new(type => CTRL_INFO_PKG);
    $available->load("$Dpkg::ADMINDIR/available");

=item dir

The directory where the cpan distribution was unpacked.

=item intrusive

A flag indicating permission to use L<Module::Depends::Intrusive> for
discovering dependencies in case L<Module::Depends> fails. Since this requires
loading all Perl modules in the distribution (and running their BEGIN blocks
(and the BEGIN blocks of their dependencies, recursively), it is recommended to
use this only when dealing with trusted sources.

=item require_deps

If true, causes the method to die if some a package for some dependency cannot
be found. Otherwise only a warning is issued.

=item verbose

=item wnpp_query

An instance of L<Debian::WNPP::Query> to be used when checking for WNPP bugs of
depended upon packages.

=back

Returns a list of module names for which no suitable Debian packages were
found.

=cut

sub _install_deb {
    my ($deb, $verbose) = @_;
    return if $deb eq 'libdbd-sqlite3-perl' || $deb eq 'libdbd-sqlite-perl';
    my $inst_cmd = "apt-get -y install $deb";
    $inst_cmd = "sudo $inst_cmd" if $>;
    print "Running '$inst_cmd'..." if $verbose;
    system($inst_cmd) == 0
        || die "Cannot install package $deb\n";
}

sub discover_dependencies {
    my ( $self, $opts ) = @_;

    $opts //= {};
    ref($opts) and ref($opts) eq 'HASH'
        or die 'Usage: $obj->{ [ { opts hash } ] )';
    my $apt_contents = delete $opts->{apt_contents};
    my $dpkg_available = delete $opts->{dpkg_available};
    my $dir = delete $opts->{dir};
    my $intrusive = delete $opts->{intrusive};
    my $require_deps = delete $opts->{require_deps};
    my $verbose = delete $opts->{verbose};
    my $install_deps = delete $opts->{install_deps};
    my $install_build_deps = delete $opts->{install_build_deps};
    my $wnpp_query = delete $opts->{wnpp_query};
    my $guess_nocheck = delete $opts->{guess_nocheck};

    die "Unsupported option(s) given: " . join( ', ', sort( keys(%$opts) ) )
        if %$opts;

    my $src = $self->source;
    my $bin = $self->binary_tie->Values(0);

    local @INC = ( $dir, @INC );

    # try Module::Depends, but if that fails then
    # fall back to Module::Depends::Intrusive.

    my $finder = Module::Depends->new->dist_dir($dir);
    my $deps;
    do {
        no warnings;
        local *STDERR;
        open( STDERR, ">/dev/null" );
        $deps = $finder->find_modules;
    };

    my $error = $finder->error();
    if ($error) {
        if ($verbose) {
            warn '=' x 70, "\n";
            warn "Failed to detect dependencies using Module::Depends.\n";
            warn "The error given was:\n";
            warn "$error";
        }

        if ( $intrusive ) {
            warn "Trying again with Module::Depends::Intrusive ... \n"
                if $verbose;
            require Module::Depends::Intrusive;
            $finder = Module::Depends::Intrusive->new->dist_dir($dir);
            do {
                no warnings;
                local *STDERR;
                open( STDERR, ">/dev/null" );
                $deps = $finder->find_modules;
            };

            if ( $finder->error ) {
                if ($verbose) {
                    warn '=' x 70, "\n";
                    warn
                        "Could not find the "
                        . "dependencies for the requested module.\n";
                    warn "Generated error: " . $finder->error;

                    warn "Please bug the module author to provide a"
                        . " proper META.yml file.\n"
                        . "Automatic find of" 
                        . " dependencies failed. You may want to \n"
                        . "retry using the '--[b]depends[i]' options\n"
                        . "or just fill the dependency fields in debian/control"
                        . " by hand\n";

                        return;
                }
            }
        }
        else {
            if ($verbose) {
                warn "If you understand the security implications, try --intrusive.\n";
                warn '=' x 70, "\n";
            }
            return;
        }
    }

    # run-time
    my ( $debs, $missing )
        = $self->find_debs_for_modules( $deps->{requires}, $apt_contents,
            $verbose, $dpkg_available );

    if (@$debs) {
        if ($verbose) {
            print "\n";
            print "Needs the following debian packages: "
                . join( ", ", @$debs ) . "\n";
        }
        $bin->Depends->add(@$debs);

        # add runtime dependencies to Build-Depends{,-Indep} as well,
        # as they are most likely needed for tests, but mark
        # them as '!<nocheck>' like the test dependencies
        my $r_debs = Debian::Dependencies->new($debs);
        foreach (@$r_debs) {
            $_->{profile} = '!nocheck' unless is_core_perl_package($_->{pkg});
        }

        if ( $bin->Architecture eq 'all' ) {
            $src->Build_Depends_Indep->add(@$r_debs);
        }
        else {
            $src->Build_Depends->add(@$r_debs);
        }

        if ($install_deps) {
            foreach my $deb (@$debs) {
                _install_deb($deb->pkg) unless grep {$deb} @$missing;
            }
        }
    }

    # build-time
    my ( $b_debs, $b_missing ) = $self->find_debs_for_modules(
        {   %{ $deps->{build_requires}     || {} },
            %{ $deps->{configure_requires} || {} }
        },
        $apt_contents,
        $verbose,
        $dpkg_available,
    );
    push @$missing, @$b_missing;

    # still build-time but test_requires only
    my ( $t_debs, $t_missing ) = $self->find_debs_for_modules(
        {   %{ $deps->{test_requires} || {} }
        },
        $apt_contents,
        $verbose,
        $dpkg_available,
    );
    push @$missing, @$t_missing;

    # add <!nocheck> profile to test dependencies
    foreach (@$t_debs) {
        $_->{profile} = '!nocheck' unless is_core_perl_package($_->{pkg});
    }

    # add <!nocheck> when there are no declared test dependencies
    # to new as well as existing (on refresh)
    # build dependencies that are likely to be used only for testing
    # if Debian::PkgPerl::Util is not available, or the --guess-nocheck option
    # is not specified, limit only to libtest-*
    unless (@$t_debs) {
        if ($guess_nocheck and eval { require Debian::PkgPerl::Util }) {
            foreach (
                @$b_debs,
                @{$src->Build_Depends},
                @{$src->Build_Depends_Indep}
                )
            {
                $_->{profile} = '!nocheck'
                    unless Debian::PkgPerl::Util->probable_build_dependency(
                        $_->{pkg});
            }
        }
        else {
            foreach (
                @$b_debs,
                @{$src->Build_Depends},
                @{$src->Build_Depends_Indep}
                )
            {
                $_->{profile} = '!nocheck' if $_->{pkg} =~ /^libtest-/;
            }
        }
    }

    if (@$b_debs || @$t_debs) {
        if ($verbose) {
            print "\n";
            print "Needs the following debian packages during building and testing: "
                . join( ", ", @$b_debs, @$t_debs ) . "\n";
        }
        if ( $self->is_arch_dep ) {
            $src->Build_Depends->add(@$b_debs);
            $src->Build_Depends->add(@$t_debs);
        }
        else {
            $src->Build_Depends_Indep->add(@$b_debs);
            $src->Build_Depends_Indep->add(@$t_debs);
        }
        if ( $install_build_deps || $install_deps ) {
            _install_deb( $_->pkg ) foreach ( @$b_debs, @$t_debs );
        }
    }

    # s/perl/perl:native/ in Build-Depends
    if ( $self->is_arch_dep ) {
        my ($perl) = $src->Build_Depends->remove('perl');
        if ($perl) {
            $perl->{pkg} = 'perl:native';
            $src->Build_Depends->add($perl);
        }
    }

    if (@$missing) {
        my ($missing_debs_str);
        if ($apt_contents) {
            $missing_debs_str
                = "Needs the following modules for which there are no debian packages available:\n";
            for (@$missing) {
                my $bug
                    = $wnpp_query
                    ? ( $wnpp_query->bugs_for_package($_) )[0]
                    : undef;
                $missing_debs_str .= " - $_";
                $missing_debs_str .= " (" . $bug->type_and_number . ')'
                    if $bug;
                $missing_debs_str .= "\n";
            }
        }
        else {
            $missing_debs_str = "The following Perl modules are required and not installed in your system:\n";
            for (@$missing) {
                my $bug
                    = $wnpp_query
                    ? ( $wnpp_query->bugs_for_package($_) )[0]
                    : undef;
                $missing_debs_str .= " - $_";
                $missing_debs_str .= " (" . $bug->type_and_number . ')'
                    if $bug;
                $missing_debs_str .= "\n";
            }
            $missing_debs_str .= <<EOF
You do not have 'apt-file' currently installed, or have not ran
'apt-file update' - If you install it and run 'apt-file update' as
root, I will be able to tell you which Debian packages are those
modules in (if they are packaged).
EOF
        }

        if ($require_deps) {
            die $missing_debs_str;
        }
        else {
            warn $missing_debs_str;
        }

    }

    return @$missing;
}

=item find_debs_for_modules I<dep hash>[, APT contents[, verbose[, DPKG available]]]

Scans the given hash of dependencies ( module => version ) and returns
matching Debian package dependency specification (as an instance of
L<Debian::Dependencies> class) and a list of missing modules.

Installed packages and perl core are searched first, then the APT contents.

If a Dpkg::Index object is passed, also check the available package version.

=cut

sub find_debs_for_modules {

    my ( $self, $dep_hash, $apt_contents, $verbose, $dpkg_available ) = @_;

    my $debs = Debian::Dependencies->new();
    my $aptpkg_cache = apt_cache();

    my @missing;

    while ( my ( $module, $version ) = each %$dep_hash ) {

        my $ver_rel;

        ( $ver_rel, $version ) = split_version_relation($version) if $version;

        $version =~ s/^v// if $version;

        my ( $dep, $core_dep, $direct_dep );

        if ( my $ver = is_core_module( $module, $version ) ) {
            $core_dep = Debian::Dependency->new( 'perl', $ver );
        }
        if (!$direct_dep && $apt_contents) {
            $direct_dep = $apt_contents->find_perl_module_package( $module, $version );

            # Check the actual version in APT, if we've got
            # a AptPkg::Cache object to search
            if ( $direct_dep && $aptpkg_cache ) {
                my $pkg = $aptpkg_cache->{$direct_dep->pkg};
                if ( my $available = $pkg->{VersionList} ) {
                    my $found = 0;
                    for my $v ( @$available ) {
                        my $d = Debian::Dependency->new( $direct_dep->pkg, '=', $v->{VerStr} );

                        next unless $d->satisfies($direct_dep);

                        $found = 1;
                        last;
                    }

                    unless ($found) {
                        push @missing, $module;
                        print "$module packages in APT do not satisfy $direct_dep"
                            if $verbose;
                    }
                }
            }
        }

        if (!$direct_dep) {
            require Debian::DpkgLists;
            if ( my @pkgs = Debian::DpkgLists->scan_perl_mod($module) ) {
                # core packages should be included above
                # it is normal to have them here, in case the version
                # requirement can't be satisfied by the current perl
                @pkgs = grep { !is_core_perl_package($_) } @pkgs;

                if (@pkgs) {
                    $direct_dep = Debian::Dependency->new(
                          ( @pkgs > 1 )
                        ? [ map { { pkg => $_, ver => $version } } @pkgs ]
                        : ( $pkgs[0], $version )
                    );

                    # Check the actual version available, if we've been passed
                    # a Dpkg::Index object
                    # (evaluates as "$thing" in boolean context;
                    # takes 6.5 seconds)
                    if ( defined $dpkg_available ) {
                        my @available;
                        my @satisfied = grep {
                            if ( my $pkg = $dpkg_available->get_by_key($_) ) {
                                my $have_pkg = Debian::Dependency->new( $_, '=', $pkg->{Version} );
                                push @available, $have_pkg;
                                $have_pkg->satisfies($direct_dep);
                            }
                            else {
                                warn qq(Unable to obtain version information for "$module" with Dpkg::Index. )
                                    .qq(You may need to run "apt-cache dumpavail | dpkg --merge-avail");
                            }
                        } @pkgs;
                        unless ( @satisfied ) {
                            print "$module is available locally as @available, but does not satisfy $version\n"
                                if $verbose;
                            push @missing, $module;
                        }
                    }
                }
            }
        }

        $dep = $direct_dep || $core_dep;
        $dep->rel($ver_rel) if $dep and $ver_rel and $dep->ver;

        my $mod_ver = join( " ", $module, $ver_rel // (), $version || () );
        if ($dep) {
            print "+ $mod_ver found in $dep\n" if $verbose
        }
        else {
            print "- $mod_ver not found in any package\n";
            push @missing, $module;

            my $mod = find_cpan_module($module);
            if ( $mod and $mod->distribution ) {
                ( my $dist = $mod->distribution->base_id ) =~ s/-v?\d[^-]*$//;
                my $pkg = $self->module_name_to_pkg_name($dist);

                print "   CPAN contains it in $dist\n";
                print "   substituting package name of $pkg\n";

                $dep = Debian::Dependency->new( $pkg, $ver_rel, $version );
            }
            else {
                print "   - it seems it is not available even via CPAN\n";
            }
        }

        $debs->add($dep) if $dep;
    }

    return $debs, \@missing;
}

=item prune_simple_perl_dep

Input:

=over

=item dependency object

shall be a simple dependency (no alternatives)

=item (optional) build dependency flag

true value indicates the dependency is a build-time one

=back


The following checks are made

=over

=item dependencies on C<perl-modules*> and C<libperl*>

These are replaced with C<perl> as per Perl policy.

=item dependencies on C<perl-base> and build-dependencies on C<perl> or
C<perl-base>

These are removed, unless they specify a version greater than the one available
in C<oldstable> or the dependency relation is not C<< >= >> or C<<< >> >>>.

=back

Return value:

=over

=item undef

if the dependency is redundant.

=item pruned dependency

otherwise. C<perl-modules*> and C<libperl*> replaced with C<perl>.

=back

=cut

sub prune_simple_perl_dep {
    my( $self, $dep, $build ) = @_;

    croak "No alternative dependencies can be given"
        if $dep->alternatives;

    return $dep unless is_core_perl_package( $dep->pkg );

    # perl-modules is replaced with perl
    $dep->pkg('perl')
      if $dep->pkg =~ /^(?:perl-modules(?:-[\d.]+)?|libperl[\d.]+)$/;

    my $unversioned = (
        not $dep->ver
            or $dep->rel =~ />/
            and $dep->ver <= $self->oldstable_perl_version
    );

    # if the dependency is considered unversioned, make sure there is no
    # version
    if ($unversioned) {
        $dep->ver(undef);
        $dep->rel(undef);
    }

    # perl-base is (build-)essential
    return undef
        if $dep->pkg eq 'perl-base' and $unversioned;

    # perl is needed in build-dependencies (see Policy 4.2)
    return $dep if $dep->pkg =~ '^perl(:native)?$' and $build;

    # unversioned perl non-build-dependency is redundant, because it will be
    # covered by ${perl:Depends}
    return undef
        if not $build
            and $dep->pkg eq 'perl'
            and $unversioned;

    return $dep;
}

=item prune_perl_dep

Similar to L</prune_simple_perl_dep>, but supports alternative dependencies.
If any of the alternatives is redundant, the whole dependency is considered
redundant.

=cut

sub prune_perl_dep {
    my( $self, $dep, $build ) = @_;

    return $self->prune_simple_perl_dep( $dep, $build )
        unless $dep->alternatives;

    for my $simple ( @{ $dep->alternatives } ) {
        my $pruned = $self->prune_simple_perl_dep( $simple, $build );

        # redundant alternative?
        return undef unless $pruned;

        $simple = $pruned;
    }

    return $dep;
}

=item prune_perl_deps

Remove redundant (build-)dependencies on perl, libperl, perl-modules and
perl-base.

=cut

sub prune_perl_deps {
    my $self = shift;

    # remove build-depending on ancient perl versions
    for my $perl ( qw( perl perl-base perl-modules perl:native ) ) {
        for ( qw( Build_Depends Build_Depends_Indep ) ) {
            my @ess = $self->source->$_->remove($perl);
            # put back non-redundant ones (possibly modified)
            for my $dep (@ess) {
                my $pruned = $self->prune_perl_dep( $dep, 1 );

                $self->source->$_->add($pruned) if $pruned;
            }
        }
    }

    # remove depending on ancient perl versions
    for my $perl ( qw( perl perl-base perl-modules perl:native ) ) {
        for my $pkg ( $self->binary_tie->Values ) {
            for my $rel ( qw(Depends Recommends Suggests) ) {
                my @ess = $pkg->$rel->remove($perl);
                for my $dep (@ess) {
                    my $pruned = $self->prune_perl_dep( $dep, 0 );

                    $pkg->$rel->add($pruned) if $pruned;
                }
            }
        }
    }
}

=back

=head1 CLASS METHODS

=over

=item module_name_to_pkg_name

Receives a perl module name like C<Foo::Bar> and returns a suitable Debian
package name for it, like C<libfoo-bar-perl>.

=cut

sub module_name_to_pkg_name {
    my ( $self, $module ) = @_;

    my $pkg = lc $module;

    # ensure policy compliant names and versions (from Joeyh)...
    $pkg =~ s/[^-.+a-zA-Z0-9]+/-/g;

    $pkg =~ s/--+/-/g;

    $pkg = 'lib' . $pkg unless $pkg =~ /^lib/;
    $pkg .= '-perl';

    return $pkg;
}

=back

=head1 COPYRIGHT & LICENSE

Copyright (C) 2009, 2010, 2012 Damyan Ivanov L<dmn@debian.org>

Copyright (C) 2019, 2020 gregor herrmann L<gregoa@debian.org>

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License version 2 as published by the Free
Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.

=cut

1;


