package Tree::Transform;
use strict;
use warnings;
use Sub::Exporter;
use Params::Validate ':all';
use Tree::Transform::Utils;
use Tree::Transform::Transformer;
use Carp::Clan qw(^Tree::Transform);

our $VERSION='0.1';

Sub::Exporter::setup_exporter({
    exports => [qw(tree_rule default_rules new_transformer)],
    groups => {
        default => [ 'tree_rule',
                     'default_rules',
                     'new_transformer' => {-as => 'new'} ],
    }
});

sub default_rules {
    my $store=Tree::Transform::Utils::_rules_store(scalar caller);

    push @{$store->{by_match}},
        {match=> '/',priority=>0,action=>sub { $_[0]->apply_rules } },
        {match=> '*',priority=>0,action=>sub { $_[0]->apply_rules } },
            ;
    return;
}

sub tree_rule {
    my (%args)=validate(@_, {
        match => { type => SCALAR, optional => 1 },
        action => { type => CODEREF },
        name => { type => SCALAR, optional => 1},
        priority => { type => SCALAR, default => 1 },
    });

    # TODO at least one of 'name' and 'match' must be specified
    # TODO default priority mased on match

    my $store=Tree::Transform::Utils::_rules_store(scalar caller);

    if ($args{match}) {
        push @{$store->{by_match}},\%args;
    }
    if ($args{name}) {
        if (exists $store->{by_name}{$args{name}}) {
            carp "Duplicate rule named $args{name}, ignoring";
            return;
        }
        $store->{by_name}{$args{name}}=\%args;
    }

    return;
}

sub _transformer_class { 'Tree::Transform::Transformer' };

sub new_transformer {
    my ($rules_package)=@_;

    return _transformer_class->new(rules_package=>$rules_package);
}

1;
__END__

=head1 NAME

Tree::Transform - transform tree data, like XSLT but in Perl

=head1 AUTHOR

Gianni Ceccarelli <dakkar@thenautilus.net>

=cut