#line 1
##############################################################################
#      $URL: http://perlcritic.tigris.org/svn/perlcritic/trunk/distributions/Perl-Critic/lib/Perl/Critic/Policy/ValuesAndExpressions/ProhibitLongChainsOfMethodCalls.pm $
#     $Date: 2011-12-21 14:40:10 -0800 (Wed, 21 Dec 2011) $
#   $Author: thaljef $
# $Revision: 4106 $
##############################################################################

package Perl::Critic::Policy::ValuesAndExpressions::ProhibitLongChainsOfMethodCalls;

use 5.006001;
use strict;
use warnings;
use Readonly;

use Perl::Critic::Utils qw{ :characters :severities };
use Perl::Critic::Utils::PPI qw{ is_ppi_expression_or_generic_statement };

use base 'Perl::Critic::Policy';

our $VERSION = '1.117';

#-----------------------------------------------------------------------------

Readonly::Scalar my $EXPL =>
    q{Long chains of method calls indicate code that is too tightly coupled};

#-----------------------------------------------------------------------------

sub supported_parameters {
    return (
        {
            name            => 'max_chain_length',
            description     => 'The number of chained calls to allow.',
            default_string  => '3',
            behavior        => 'integer',
            integer_minimum => 1,
        },
    );
}

sub default_severity { return $SEVERITY_LOW          }
sub default_themes   { return qw( core maintenance ) }
sub applies_to       { return qw{ PPI::Statement };  }

#-----------------------------------------------------------------------------

sub _max_chain_length {
    my ( $self ) = @_;

    return $self->{_max_chain_length};
}

#-----------------------------------------------------------------------------

sub violates {
    my ( $self, $elem, undef ) = @_;

    return if not is_ppi_expression_or_generic_statement($elem);

    my $chain_length = 0;
    my $max_chain_length = $self->_max_chain_length();
    my @children = $elem->schildren();
    my $child = shift @children;

    while ($child) {
        # if it looks like we've got a subroutine call, drop the parameter
        # list.
        if (
                $child->isa('PPI::Token::Word')
            and @children
            and $children[0]->isa('PPI::Structure::List')
        ) {
            shift @children;
        }

        if (
                $child->isa('PPI::Token::Word')
            or  $child->isa('PPI::Token::Symbol')
        ) {
            if ( @children ) {
                if ( $children[0]->isa('PPI::Token::Operator') ) {
                    if ( q{->} eq $children[0]->content() ) {
                        $chain_length++;
                        shift @children;
                    }
                }
                elsif ( not  $children[0]->isa('PPI::Token::Structure') ) {
                    $chain_length = 0;
                }
            }
        }
        else {
            if ($chain_length > $max_chain_length) {
                return
                    $self->violation(
                        "Found method-call chain of length $chain_length.",
                        $EXPL,
                        $elem,
                    );
            }

            $chain_length = 0;
        }

        $child = shift @children;
    }

    if ($chain_length > $max_chain_length) {
        return
            $self->violation(
                "Found method-call chain of length $chain_length.",
                $EXPL,
                $elem,
            );
    }

    return;
}


1;

__END__

#-----------------------------------------------------------------------------

#line 189

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