#!/usr/bin/perl -w
use strict;
use AI::Perlog;

my $pg = AI::Perlog->new;
load_data();

my $acts_of_horror = who_steals_from_whom();

unless ( @$acts_of_horror ) {
	print "Looks like everybody's safe\n";
}
else {
	foreach my $crime ( @$acts_of_horror ) {
		my ( $thief, $victim ) = @$crime;
		print "$thief will steal from $victim.\n";
	}
}

exit;

sub who_steals_from_whom {
	my $thieves = $pg->thief( '$person' );
	my $victims = $pg->owns( qw/ $person _ / );

	my @crimes;
	foreach my $victim ( @$victims ) {
		my $curr_victim = $victim->{person};
		foreach my $thief ( @$thieves ) {
			my $curr_thief = $thief->{person};
			if (rich($curr_victim) and ! $pg->knows($curr_thief,$curr_victim)){
				push @crimes =>  [$curr_thief, $curr_victim];
			}
		}
	}
	return \@crimes;
}

sub rich {
	my $person = shift;
	my $items = $pg->owns( $person, '$item' );
	local $_;
	foreach ( @$items ) {
		return 1 if $pg->valuable( $_->{ item } );
	}
	return;
}

sub load_data {
	while ( <DATA> ) {
		chomp;
		next if ( ! $_ or substr( $_, 0, 1 ) eq '#' );
		my @fact = split /\t/;
		$pg->add_fact( @fact );
	}
}

__DATA__
owns	merlyn	gold
owns	Ovid	pocket lint
owns	Ovid	cheap whiskey
owns	kudra	domination fund

valuable	gold
valuable	domination fund

thief	badguy
thief	badgirl

# :)
knows	badgirl	merlyn