package DTL::Fast::Expression::Operator::Binary::Eq;
use strict; use utf8; use warnings FATAL => 'all'; 
use parent 'DTL::Fast::Expression::Operator::Binary';

$DTL::Fast::Expression::Operator::KNOWN{'=='} = __PACKAGE__;

use Scalar::Util qw(looks_like_number);
use DTL::Fast::Utils qw(has_method);


# @todo Recurursion protection on deep comparision or one-level comparision
sub dispatch
{
    my( $self, $arg1, $arg2) = @_;
    my ($arg1_type, $arg2_type) = (ref $arg1, ref $arg2);
    my $result = 0;

    if( 
        not defined $arg1 and defined $arg2 
        or not defined $arg2 and defined $arg1
    )
    {
        $result = 0;
    }
    elsif( not defined $arg1 and not defined $arg2 )
    {
        $result = 1; # @todo think about comparing two undefs
    }
    elsif( looks_like_number($arg1) and looks_like_number($arg2))
    {
        $result = ($arg1 == $arg2);
    }
    elsif( $arg1_type eq 'ARRAY'  and $arg2_type eq 'ARRAY' )
    {
        if( scalar @$arg1 == scalar @$arg2 )
        {
            $result = 1;
            for( my $i = 0; $i < scalar @$arg1; $i++ )
            {
                if( not dispatch($self, $arg1->[$i], $arg2->[$i] ))
                {
                    $result = 0;
                    last;
                }
            }
        }
    }
    elsif( $arg1_type eq 'HASH' and $arg2_type eq 'HASH' )
    {
        my @keys1 = sort keys %$arg1;
        my @keys2 = sort keys %$arg2;
        
        if( dispatch( $self, \@keys1, \@keys2 ) )
        {
            my $result = 1;
            foreach my $key (@keys1)
            {
                if( not dispatch($self, $arg1->{$key}, $arg2->{$key} ))
                {
                    $result = 0;
                    last;
                }
            }
        }        
    }
    elsif( has_method($arg1, 'equal'))
    {
        $result = $arg1->equal($arg2);
    }
    elsif( has_method($arg2, 'equal'))
    {
        $result = $arg2->equal($arg1);
    }
    else
    {
        $result = ($arg1 eq $arg2);
    }
    
    return $result;
}

1;