#!/usr/bin/perl

use strict;
use CGI qw(:standard);
use Data::Dumper;
use LWP::UserAgent;
use RDF::Redland;
use URI::Escape;
use XML::Simple;

my $endpoints = {
	'query'    => 'http://127.0.0.1:2020/service/mttl' ,
	'update'   => 'http://127.0.0.1:2020/service/mttl-update' ,
	};
my $uastring = "mttlbot-graphs/0.1 ";

my $g = param('uri');
die "Bad URI" if $g =~ /[<>\s\r\n]/;

print header("text/turtle; charset=utf-8");
my $r = _sparql('query', 'GET',
	"CONSTRUCT { ?s ?p ?o } WHERE { GRAPH <$g> { ?s ?p ?o } . }");
print $r->{'raw'}."\n";

sub _sparql
{
	my ($endpoint_id, $method, $query, $graph) = @_;
	
	my $endpoint = $endpoints->{$endpoint_id};
	my $queryparam = ($endpoint_id =~ /update/) ? 'request' : 'query';
	my $params = {
		$queryparam => $query
		};
	$params->{'default-graph-uri'} = $graph
		if defined $graph;
	my $paramstring = '';
	foreach my $k (keys %$params)
	{
		$paramstring .= sprintf('&%s=%s', $k, uri_escape($params->{$k}));
	}
	$paramstring =~ s/^\&/\?/;

	my $ua  = LWP::UserAgent->new('timeout'=>60, 'agent'=>"$uastring ");
	$ua->default_header('Accept'=>'text/turtle, application/turtle, application/x-turtle');
	my $res = ($method eq 'POST')
	        ? $ua->post($endpoint, $params)
	        : $ua->get($endpoint . $paramstring);

	if (($res->code == 200)
	&&  ($res->header('content-type')=~/sparql.results/)
	&&  (length $res->content))
	{
		my $rv = {};
		$rv->{'raw'}  = $res->content;
		$rv->{'tree'} = XMLin($rv->{'raw'}, 'ForceArray'=>[qw(variable binding result)], 'KeyAttr'=>[]);
		
		if (defined $rv->{'tree'}->{'boolean'})
		{
			if ('false' eq lc $rv->{'tree'}->{'boolean'})
			{
				$rv->{'boolean'} = 0;
			}
			elsif ('true' eq lc $rv->{'tree'}->{'boolean'})
			{
				$rv->{'boolean'} = 1;
			}
		}
		elsif (defined $rv->{'tree'}->{'results'})
		{
			foreach my $v (@{ $rv->{'tree'}->{'head'}->{'variable'} })
			{
				push @{$rv->{'cols'}}, $v->{'name'};
			}

			foreach my $r (@{ $rv->{'tree'}->{'results'}->{'result'} })
			{
				my $x = {};
				foreach my $b (@{ $r->{'binding'} })
				{
					$x->{ $b->{'name'} } = {
						'uri'     => $b->{'uri'} ,
						'bnode'   => $b->{'bnode'} ,
						'literal' => $b->{'literal'} ,
						'curie'   => _curie($b->{'uri'}) ,
						};
						
					if ('HASH' eq ref $x->{ $b->{'name'} }->{'literal'})
					{
						$x->{ $b->{'name'} }->{'datatype'}  = $b->{'literal'}->{'datatype'};
						$x->{ $b->{'name'} }->{'literal'}   = $b->{'literal'}->{'content'};
						$x->{ $b->{'name'} }->{'datacurie'} = _curie($b->{'literal'}->{'datatype'});
					}
				}
				push @{$rv->{'results'}}, $x;
			}
		}
		
		$rv->{'ok'} = 1;
		return $rv;
	}
	elsif (($res->code == 200) && ($res->header('content-type')=~/rdf.xml/))
	{
		return {
			'ok'    => 1,
			'rdf'   => 1,
			'raw'   => $res->content,
#			'model' => _get_redland_model('http://invalid.invalid/', $res),
			};
	}
	elsif ($res->code == 200)
	{
#		print "--> Unknown content: <<EOF\n";
#		print $res->content."\n";
#		print "EOF\n";
		return {
			'ok' => 1 ,
			'raw'   => $res->content,
			};
	}
	else
	{
		return { 'error'=>sprintf('%s [%s]', $res->message, (120<(length $query) ? ((substr $query, 0, 110).'...') : $query)) };
	}
}