package Markdent::Role::BalancedEvent;

use strict;
use warnings;
use namespace::autoclean;

our $VERSION = '0.30';

use List::AllUtils qw( all );
use Markdent::Types;
use Params::ValidationCompiler qw( validation_for );
use Specio::Declare;

use MooseX::Role::Parameterized;

parameter compare => (
    isa => t( 'ArrayRef', of => t('Str') ),
);

role {
    my $p = shift;

    my @compare = @{ $p->compare() || [] };

    my $validator = validation_for(
        params => [
            { type => t('EventObject') },
        ],
    );

    method balances_event => sub {
        my $self = shift;
        my ($other) = $validator->(@_);

        return 0 unless $self->name() eq $other->name();

        return 0
            unless ( $self->is_start() && $other->is_end() )
            || ( $self->is_end() && $other->is_start() );

        return 1 unless @compare;

        return all { $self->$_() eq $other->$_() } @compare;
    };
};

1;

# ABSTRACT: A parameterized role for events which can check if they balance another event

__END__

=pod

=encoding UTF-8

=head1 NAME

Markdent::Role::BalancedEvent - A parameterized role for events which can check if they balance another event

=head1 VERSION

version 0.30

=head1 DESCRIPTION

This role provides behavior for start and end events which can be checked for
a balancing event. This includes things like strong, emphasis, and code
start/end events.

=head1 ROLE PARAMETERS

This role accepts the following parameters:

=over 4

=item * compare => [ ... ]

This should be a list of attribute names which will be compared between the
start and end events.

=back

=head1 METHODS

This role provides the following methods:

=head2 $event->balances_event($event2)

Given an event, this returns true if two events balance each other. This is
done by comparing types (StartCode matches EndCode), as well as the attributes
provided in the compare parameter.

=head1 BUGS

See L<Markdent> for bug reporting details.

Bugs may be submitted at L<http://rt.cpan.org/Public/Dist/Display.html?Name=Markdent> or via email to L<bug-markdent@rt.cpan.org|mailto:bug-markdent@rt.cpan.org>.

I am also usually active on IRC as 'autarch' on C<irc://irc.perl.org>.

=head1 SOURCE

The source code repository for Markdent can be found at L<https://github.com/houseabsolute/Markdent>.

=head1 AUTHOR

Dave Rolsky <autarch@urth.org>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2018 by Dave Rolsky.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

The full text of the license can be found in the
F<LICENSE> file included with this distribution.

=cut