package Perl::Metrics::Lite::Analysis::Util;
use strict;
use warnings;
use English qw(-no_match_vars);
use Readonly;

Readonly::Scalar my $ALL_NEWLINES_REGEX => ## no critic
    qr/ ( \Q$INPUT_RECORD_SEPARATOR\E ) /sxm; 

Readonly::Scalar my $LAST_CHARACTER => -1; ## no critic

sub get_node_length {
    my $node = shift;
    my $eval_result = eval { $node = prune_non_code_lines($node); };
    return 0 if not $eval_result;
    return 0 if ( !defined $node );
    my $string = $node->content;
    return 0 if ( !length $string );

    $string = _normailze_string($string);
    my $line_count = _count_lines($string);

    return $line_count;
}

sub _normailze_string {
    my $string = shift;
    
    # Replace whitespace-newline with newline
    $string
        =~ s/ \s+ \Q$INPUT_RECORD_SEPARATOR\E /$INPUT_RECORD_SEPARATOR/smxg;
    $string =~ s/\Q$INPUT_RECORD_SEPARATOR\E /$INPUT_RECORD_SEPARATOR/smxg;
    $string =~ s/ \A \s+ //msx;    # Remove leading whitespace
    $string;
}

sub _count_lines {
    my $string = shift;
    my @newlines = ( $string =~ /$ALL_NEWLINES_REGEX/smxg );
    my $line_count = scalar @newlines;

    # if the string is not empty and the last character is not a newline then add 1
    if ( length $string ) {
        my $last_char = substr $string, $LAST_CHARACTER, 1;
        if ( $last_char ne "$INPUT_RECORD_SEPARATOR" ) {
            $line_count++;
        }
    }
    return $line_count;
}

sub get_packages {
    my $document = shift;

    my @unique_packages = ();
    my $found_packages  = $document->find('PPI::Statement::Package');

    return \@unique_packages
        if (
        !Perl::Metrics::Lite::Analysis::Util::is_ref( $found_packages, 'ARRAY' ) );

    my %seen_packages = ();

    foreach my $package ( @{$found_packages} ) {
        $seen_packages{ $package->namespace() }++;
    }

    @unique_packages = sort keys %seen_packages;

    return \@unique_packages;
}

sub prune_non_code_lines {
    my $document = shift;
    if ( !defined $document ) {
        Carp::confess('Did not supply a document!');
    }
    $document->prune('PPI::Token::Comment');
    $document->prune('PPI::Token::Pod');
    $document->prune('PPI::Token::End');

    return $document;
}

sub is_ref {
    my $thing = shift;
    my $type  = shift;
    my $ref   = ref $thing;
    return if !$ref;
    return if ( $ref ne $type );
    return $ref;
}

1;

__END__

=encoding utf-8

=head1 NAME

Perl::Metrics::Lite::Analysis::Util - Utility class for PPI::Document operation

=head1 STATIC PACKAGE SUBROUTINES

Utility subs used internally, but no harm in exposing them for now.
Call these with a fully-qualified package name, e.g.

  Perl::Metrics::Lite::Analysis::Util::is_ref($thing,'ARRAY')

=head2 get_packages

Arrayref of unique PPI::Statement::Package found in the PPI document.

=head2 get_node_length

Takes a B<PPI> node and returns a count of the newlines it
contains. B<PPI> normalizes line endings to newlines so
CR/LF, CR and LF all come out the same. The line counts reported by
the various methods in this class all B<exclude> blank lines,
comment lines and pod
(the B<PPI> document is pruned before counting.)

=head2 is_ref

Takes a I<thing> and a I<type>. Returns true is I<thing> is a reference
of type I<type>, otherwise returns false.

=cut