#!/usr/bin/perl

use 5.008005;
use strict;
use warnings;
use Time::HiRes  1.97 ();
use Getopt::Long 2.33 ();

=pod

=head1 NAME

cpangraph - Generate dependency chain graphs for CPAN modules

=head1 VERSION

Version 0.12

=cut

our $VERSION = '0.18';

use CPANDB ();

# Check params
my $PERL    = undef;
my $PHASE   = undef;
my $VERBOSE = 0;
my $RANKDIR = 0;
my $REVERSE = 0;

=pod

=head1 SYNOPSIS

  cpangraph [options] <file>

    Options:
      --help            display a brief help message
      --perl=VERSION    filter those available in Perl core
      --phase=PHASE     filter those needed for a phase (e.g., build)
      --rankdir         controls the GraphViz 'rankdir' variable
      --reverse         graph reverse dependencies (dependents)
      --verbose         display additional debugging information

=head1 OPTIONS

=over

=item B<--help>

Prints a brief help message to the standard output and exits.

=item B<--perl>=VERSION

This displays dependencies which have been available in Perl core since
the given VERSION. It does not currently know if a module has been removed
from core, but this is an unlikely occurrence. Specify Perl versions in
the form:

  5.008008 # for versions >= 5.8.8
  5.010    # for versions >= 5.10

=item B<--phase>=PHASE

This displays dependencies which are needed for a given module's install
or runtime PHASE. Available phases are:

=over

=item * runtime: required whenever the module is used

=item * build: required to build the module

=item * configure: these are required while preparing the module for
build

=back

=item B<--rankdir>

In GraphViz, the 'rankdir' attribute controls the direction that the nodes
are linked together. If set, the graph will use left -> right linking of
nodes rather than the default up-down linking.

=item B<--reverse>

Create a graph of the reverse dependencies of a package (the packages which
depend on it, or dependent packages).

=item B<--verbose>

Display extra output useful during debugging.

=back

=cut

=head1 DESCRIPTION

B<This script> will use the CPAN Database to build a graph of a package's
dependencies or reverse dependencies (dependent packages).

=cut

Getopt::Long::GetOptions(
	'perl=s'  => \$PERL,
	'phase=s' => \$PHASE,
	'verbose' => \$VERBOSE,
	'rankdir' => \$RANKDIR,
	'reverse' => \$REVERSE,
) or die "Failed to parse options";

# Find the distribution
my $name = shift @ARGV;
unless ( $name ) {
	print "Did not provide a distribution name\n";
	exit(0);
}

# Load the database and fine the distribution
CPANDB->import( {
	show_progress => $VERBOSE,
} );
my $dist = CPANDB->distribution($name);

# Determine the graph file name
my $file = $name;
if ( $PHASE ) {
	$file .= '-' . $PHASE;
}
if ( $PERL ) {
	$file .= '-' . $PERL;
}

# Generate the graph
my $method = $REVERSE
	? 'dependants_graphviz'
	: 'dependency_graphviz';
$dist->$method(
	perl    => $PERL,
	phase   => $PHASE,
	rankdir => $RANKDIR,
)->as_svg("$file.svg");

=pod

=head1 AUTHOR

Adam Kennedy E<lt>adamk@cpan.orgE<gt>

=head1 SUPPORT

For support details, please look at C<perldoc CPANDB> and use the
corresponding support methods.

=head1 LICENSE

This has the same copyright and licensing terms as L<CPANDB>.

=cut