use warnings;
use strict;
use utf8;
use XML::LibXML;

use URI;
use HTTP::Tiny;
my $http = HTTP::Tiny->new;
my %cache;
XML::LibXML::externalEntityLoader(sub {
	my ($url, $id) = @_;
	die "Can't handle ID '$id'" if length $id;
	my $uri = URI->new($url);
	my $file;
	if (!$uri->scheme) { $file = $url }
	elsif ($uri->scheme eq 'file') { $file = $uri->path }
	if (defined $file) {
		warn "'$uri' => Loading '$file' from disk\n"; #Debug
		open my $fh, '<', $file or die "$file: $!";
		my $data = do { local $/; <$fh> };
		close $fh;
		return $data;
	} # else
	die "Can't handle URL scheme: ".$uri->scheme
		unless $uri->scheme=~/\Ahttps?\z/i;
	if (!defined $cache{$uri}) {
		warn "'$uri' => Fetching...\n"; #Debug
		my $resp = $http->get($uri);
		die "$uri: $resp->{status} $resp->{reason}\n"
			unless $resp->{success};
		$cache{$uri} = $resp->{content};
	}
	else { warn "'$uri' => Cached\n"; } #Debug
	return $cache{$uri};
});

print "Loading schema...\n";
my $xsd = XML::LibXML::Schema->new( location => 'schema.xsd' );

my @xmls = (<<'END_XML_ONE',<<'END_XML_TWO',<<'END_XML_THREE');
<?xml version="1.0" encoding="UTF-8"?>
<hello xmlns="http://www.example.com">
	<world foo="bar">
		<p xmlns="http://www.w3.org/1999/xhtml">
			<i>x</i>
		</p>
	</world>
</hello>

END_XML_ONE
<?xml version="1.0" encoding="UTF-8"?>
<hello xmlns="http://www.example.com">
	<world>
		<p xmlns="http://www.w3.org/1999/xhtml">
			<i>x</i>
		</p>
	</world>
</hello>

END_XML_TWO
<?xml version="1.0" encoding="UTF-8"?>
<hello xmlns="http://www.example.com">
	<world foo="bar">
		<p xmlns="http://www.w3.org/1999/xhtml">
			<foo>x</foo>
		</p>
	</world>
</hello>
END_XML_THREE

my $i = 1;
for my $xml (@xmls) {
	print "Validating XML #$i...\n";
	my $doc = XML::LibXML->load_xml( string => $xml );
	if ( eval { $xsd->validate($doc); 1 } )
		{ print "=> Valid!\n" }
	else { print "=> Invalid! $@" }
} continue { $i++ }