package Catmandu::Fix::move_field;

use Catmandu::Sane;

our $VERSION = '1.07';

use Moo;
use namespace::clean;
use Catmandu::Fix::Has;

with 'Catmandu::Fix::Base';

has old_path => (fix_arg => 1);
has new_path => (fix_arg => 1);

sub emit {
    my ($self, $fixer) = @_;
    my $old_path = $fixer->split_path($self->old_path);
    my $old_key  = pop @$old_path;
    my $new_path = $fixer->split_path($self->new_path);

    $fixer->emit_walk_path(
        $fixer->var,
        $old_path,
        sub {
            my $var = shift;
            $fixer->emit_delete_key(
                $var, $old_key,
                sub {
                    my $vals = shift;
                    if (
                        @$new_path
                        && (   $new_path->[-1] eq '$prepend'
                            || $new_path->[-1] eq '$append')
                        )
                    {
                        my $new_key = pop @$new_path;
                        $fixer->emit_create_path(
                            $fixer->var,
                            $new_path,
                            sub {
                                my $var = shift;
                                my $sym
                                    = $new_key eq '$prepend'
                                    ? 'unshift'
                                    : 'push';
                                "if (\@{${vals}} && is_array_ref(${var} //= [])) {"
                                    . "${sym}(\@{${var}}, \@{${vals}});"
                                    . "}";
                            }
                        );
                    }
                    else {
                        $fixer->emit_create_path(
                            $fixer->var,
                            $new_path,
                            sub {
                                my $var = shift;
                                "if (\@{${vals}}) {"
                                    . "${var} = shift(\@{${vals}});" . "}";
                            }
                        );
                    }
                }
            );
        }
    );
}

1;

__END__

=pod

=head1 NAME

Catmandu::Fix::move_field - move a field to another place in the data structure

=head1 SYNOPSIS

   # Move single fields

   # Move 'foo.bar' to 'bar.foo'
   move_field(foo.bar, bar.foo)

   # Move multipe fields
   # Data:
   # a:
   #   b: test1
   #   c: test2
   move_field(a,z)  # -> Move all the 'a' to 'z'
                    # z:
                    #   b: test1
                    #   c: test2
   # Data:
   # a:
   #   b: test1
   #   c: test2
   move_field(a,.)  # -> Move the fields 'b' and 'c' to the root
                    # b: test1
                    # c: test2

=head1 SEE ALSO

L<Catmandu::Fix>

=cut