#!/usr/bin/perl

# Catch the canid in 
# "The quick brown fox jumps over the lazy dog."

use strict;
use 5.010;	
use XML::LibXML;
use List::MoreUtils qw(uniq);

my $xml = "<foo>The quick br<bar>o</bar>wn <baz>f<bar>o</bar>x</baz>";
$xml .= " jumps over the lazy d<bar>o</bar>g.</foo>";

my $new_element = "canid";
my @queried = ("quick brown fox","lazy dog");
$xml = &doubtful_method($xml,$_) foreach @queried;

my $dom = XML::LibXML->load_xml( string => $xml);
say $dom->to_literal;

my @canids = 
	uniq map { &catch_milestone($_) } ($dom->findnodes('//canid'));
say "Canids addressed: ", join ", ", @canids;

sub doubtful_method {
	my $xml = $_[0];
	my $queried = $_[1];
	my $rex = join "(<.+?>)?", split //, $queried;
	$xml =~ s/($rex)/&evaluate_match($1)/gem;
	return $xml;
}

sub evaluate_match {
	my $match = $_[0];
	my $out;
	eval { 
		XML::LibXML->load_xml(string => "<test>".$match."</test>") 
	};
	if (ref($@)){
		my $milestone = qq|<$new_element time="| . time . qq |"/>|;
		$out = $milestone.$match.$milestone;
	} else {
		$out = "<$new_element>$match</$new_element>";
	}
	return $out;
}

sub catch_milestone {
	my $node = $_[0];
	my ($out);
	if ($node->hasAttribute("time")) {
		my $milestone = qq|<$new_element(.+?)?time="|;
		$milestone.= $node->getAttribute("time") . qq|"(.+?)?>|;
		my $rex = $milestone . "(?<new>.+?)" . $milestone;
		$out = $+{new} if $dom->documentElement->toString =~ /($rex)/;
		$out =~ s/<.+?>//gm;
	} else {	
		$out = $node->to_literal;
	}
	return $out;
}