#!/usr/bin/perl

use strict;
use warnings;

use XML::Simple;
use Data::Dumper;

die("Usage: $0 aiml.xml\n") unless($ARGV[0]);
open(XML,"<$ARGV[0]") or die("open($ARGV[0]): $!\n");
my $aiml = '';
while(<XML>) {
	$aiml .= $_;
}
close(XML);

my $parser = XML::Simple->new();
my $xml    = $parser->XMLin($aiml);

print "xml: " . Dumper($xml) . "\n";


my $knowledge = {};
my $star;

foreach my $c (@{$xml->{category}}) {
	print "pattern: $c->{pattern}\n";
	&addKnowledge($knowledge,$c->{pattern},$c->{template});
}

print "Knowledge: " . Dumper($knowledge) . "\n";

print "> ";
while(my $input = <STDIN>) {
	chomp($input);
	print &findAnswer($knowledge,$input) . "\n";
	print "> ";
}

sub findAnswer {
	my ($struct,$input) = @_;
	my ($key,$rest) = split(/\s+/,$input,2);
	unless($struct->{uc($key)}) {
		$star = $key;
		$key  = '*';
	}
	if($rest) {
		if($struct->{uc($key)}) {
			&findAnswer($struct->{uc($key)},$rest);
		} elsif($struct->{template}) {
			return(&parseAnswer($struct));
		}
	} else {
		return(&parseAnswer($struct->{uc($key)}));
	}
}

sub parseAnswer {
	my ($struct) = @_;
	if(ref($struct->{template}) eq '') {
		return($struct->{template});
	} elsif(ref($struct->{template}) eq 'HASH') {
		if($struct->{template}->{random}) {
			my @r = @{$struct->{template}->{random}->{li}};
			srand($$^time^$struct);
			return($r[rand(int($#r) + 1)]);
		}
	}
	return('I do not know what that means.');
}

sub addKnowledge {
	my ($ref,$pattern,$template) = @_;
	my ($key,$rest) = split(/\s+/,$pattern,2);
	if($rest) {
		print "addKnowledge(): $key:$rest ref=" . ref($ref) . "\n";	
		$ref->{uc($key)} = {} unless(exists $ref->{uc($key)});
		&addKnowledge($ref->{uc($key)},$rest,$template);
	} else {
		print "addKnowledge(): $key:$template\n";	
		$ref->{uc($key)}->{template} = $template;
	}
	return(1);
}