#!perl -w

use strict;

eval "use CPAN::FindDependencies;";
if($@) {
    print STDERR "Couldn't load CPAN::FindDependencies.\n";
}

my $showversion;
if($ARGV[0] eq '--showmoduleversions') {
  $showversion = 1;
  shift;
}

my $target = shift;
my @deps = CPAN::FindDependencies::finddeps(
    $target,
    nowarnings => 1,
    @ARGV
);

foreach my $dep (@deps) {
    print '  ' x $dep->depth();
    print '*' if($dep->warning());
    print $dep->name().' (dist: '.$dep->distribution();
    print ', mod ver: '.$dep->version() if($showversion && $dep->name() ne $target);
    print ")\n";
}

=head1 NAME

cpandeps - show a module on the CPAN's dependency tree.

=head1 DESCRIPTION

This program is a simple wrapper around CPAN::FindDependencies.

=head1 SYNOPSIS

    cpandeps CPAN::FindDependencies

    cpandeps CPAN::FindDependencies perl 5.8.8 cachedir ../foo/bar

    cpandeps --showmoduleversions CPAN::FindDependencies

Given a module name, this program will show you the module's
dependency tree.  It takes exactly the same arguments as the
C<finddeps> function of CPAN::FindDependencies, with the exception
that C<nowarnings> is turned *on* by default.

=over

=item nowarnings

Warnings about modules where we can't find their META.yml or Makefile.PL, and
so can't divine their pre-requisites, will be suppressed;

=item fatalerrors

Failure to get a module's dependencies will be a fatal error
instead of merely emitting a warning;

=item perl

Use this version of perl to figure out what's in core.  If not
specified, it defaults to 5.005.  Three part version numbers
(eg 5.8.8) are supported but discouraged.

=item 02packages

The location of CPAN.pm's C<02packages.details.txt.gz> file as a
local filename, with either a relative or an absolute path.  If not
specified, it is fetched from a CPAN mirror instead.  The file is
fetched just once.

=item cachedir

A directory to use for caching.  It defaults to no caching.  Even if
caching is turned on, this is only for META.yml or Makefile.PL files.
02packages is not cached - if you want to read that from a local disk, see the
C<02packages> option.

=item maxdepth

Cuts off the dependency tree at the specified depth.  Your specified
module is at depth 0, your dependencies at depth 1, their dependencies
at depth 2, and so on.

=item usemakefilepl

If set to true, then for any module that doesn't have a META.yml,
try to use its Makefile.PL as well.  Note that this involves
downloading code from the Internet and running it.  This obviously
opens you up to all kinds of bad juju, hence why it is disabled
by default.

=item recommended

Adds recommended modules to the list of dependencies, if set to a true value.


=back

It also takes the following extra parameter, which must be the first one:

=over

=item --showmoduleversions

If present, the required version of each module is also shown

=back

It shows the module name, its distribution, and if any warnings were
raised (such as if a module's dependencies couldn't be fetched) this
is indicated with an asterisk before the module's name.

=head1 WARNINGS, BUGS and FEEDBACK

This script has not been thoroughly tested.

I welcome feedback about my code, including constructive criticism.
Bug reports should be made using L<http://rt.cpan.org/> or by email.

=head1 SEE ALSO

L<CPAN::FindDependencies>

L<http://deps.cpantesters.org/>

=head1 AUTHOR, LICENCE and COPYRIGHT

Copyright 2007 - 2009 David Cantrell E<lt>F<david@cantrell.org.uk>E<gt>

This software is free-as-in-speech software, and may be used,
distributed, and modified under the terms of either the GNU
General Public Licence version 2 or the Artistic Licence. It's
up to you which one you use. The full text of the licences can
be found in the files GPL2.txt and ARTISTIC.txt, respectively.

=head1 CONSPIRACY

This software is also free-as-in-mason.

=cut