package FilterLoad;
use warnings;
use strict;
use List::Util qw/ pairs pairkeys /;
use PPI;
use Module::Load::Conditional qw/ check_install /;
use Module::Runtime qw/ use_module module_notional_filename /;

=head1 DESCRIPTION

Loads modules after passing them through the L<PPI::Transform> filter(s) given
in the C<use> statement. For example:

 use FilterLoad 'AnyEvent::DNS' => 'Deconstifier',
     SomeModule => 'Deconstifier';

=cut

sub import {
	my ($class, @defs) = @_;
	my (%mods, %filts);
	for ( pairs @defs ) {
		my ($mod, $filt) = @$_;
		$filts{$filt}++;
		my $modfn = module_notional_filename($mod);
		$mods{$modfn}{name} = $mod;
		push @{ $mods{$modfn}{filts} }, $filt;
	}
	use_module($_) for keys %filts;
	our $_in_inc_hook;
	unshift @INC, sub {
		my ($self, $modfn) = @_;
		return if $_in_inc_hook;
		return unless exists $mods{$modfn};
		local $_in_inc_hook = 1; # check_install calls @INC hooks!
		my $info = check_install(module=>$mods{$modfn}{name})
			or die "could not find $modfn";
		my $doc = PPI::Document->new($info->{file});
		$_->new->apply($doc) for @{ $mods{$modfn}{filts} };
		return \$doc->serialize;
	};
	use_module($_) for pairkeys @defs;
}

1;