<?php
/**
 * @class VOTableMgr

 * @version $Id: VOTableMgr.php 2916 2015-05-19 13:08:33Z elena $

 */

//set DEBUG_MODE to TRUE to have some log information
define("DEBUG_MODE", FALSE);

class VOTableMgr {

	public  $xml = null;
	private $log;
	private $xp;

	private $stream; // The stream in the VOTable
	private $c; // Current character position on the stream

	private $is_little_endian;

	private $votable_error = false;

  function __construct()

  {
  	 if (DEBUG_MODE)
  	   $this->log = fopen(USERDATADIR."logVOTable","w");
  }

  function addLog($msg)
  {
  	 if (DEBUG_MODE)
  	   fprintf($this->log,$msg);
  }

  function load($fileName)
  {

	$this->is_little_endian = array_values(unpack('L1L', pack('V', 1)))[0] == 1;

	// see http://php.net/manual/en/domdocument.load.php#91384
	$options = array(
		'http' => array(
			'method' => 'GET',
			'timeout' => '5',
			'user_agent' => 'PHP libxml agent',
			// If the query is wrong, epn-tap service returns an HTTP error code 400, along with xml containing some usefull informations.
			'ignore_errors' => true
		)
	);

	// BRE - Add proxy host if exists
	if (defined('HTTP_PROXY_HOST')) {
		$options['http']['proxy'] = 'tcp://'.HTTP_PROXY_HOST;
		$options['http']['request_fulluri'] = TRUE;
		if (defined('HTTP_PROXY_USER')) {
			$options['http']['header'] = "Proxy-Authorization: Basic ".base64_encode(HTTP_PROXY_USER);
		}
	}

	$context = stream_context_create($options);
	libxml_set_streams_context($context);
	$this->xml = new DomDocument();

	if (!@$this->xml->load($fileName)) {

		$this->votable_error = 'Can not load xml file.';
		return false;
	}

	$this->checkIDAttribute();

	$rootNamespace = $this->xml->lookupNamespaceUri($this->xml->namespaceURI);
	$this->xp = new domxpath($this->xml);
	$this->xp->registerNameSpace('x', $rootNamespace);

	return true;
  }

  function getVotableError() {
	  return $this->votable_error;

  }

  function isValidSchema()
  {

	if ($this->votable_error != false) {
		return false;
	}

	if (!$this->xml) {
		$this->votable_error = "The returned file is not XML.";
		return false;
	}

	$infos = $this->xp->query($this->queryResourceInfo());
	foreach($infos as $info) {
		if($info->getAttribute('value') == 'ERROR') {
			$this->votable_error = $info->textContent;

			return false;

		}

	}

  	 //ToDo - BRE - add validation!!
  	 return TRUE;

  	 if (DEBUG_MODE)
  	   libxml_use_internal_errors(true);

  	 $vers = $this->getVersion();

  	 $this->addLog("VOTable version : ".$vers."\n");

  	 $result = FALSE;

  	 switch ($vers)
  	 {
  	 	 case '1.2' :
  	 	 	 $result = $this->xml->schemaValidate(XMLPATH.'VOTable-1.2.xsd');
  	 	 case '1.0' :
  	 	 	 $result = $this->xml->schemaValidate(XMLPATH.'VOTable-1.0.xsd');
  	 	 default :
  	 	   $result = $this->xml->schemaValidate(XMLPATH.'VOTable-1.1.xsd');
  	 }

  	 if (DEBUG_MODE)
  	 {
  	   $errors = libxml_get_errors();

  	   foreach ($errors as $error)

  	   {

  	   	 $msg = '';

        switch ($error->level)
        {
          case LIBXML_ERR_WARNING:
            $msg .= ("WARNING ".$error->code.": ");
            break;
          case LIBXML_ERR_ERROR:
            $msg .= ("ERROR ".$error->code.": ");
            break;
          case LIBXML_ERR_FATAL:
            $msg .= ("FATAL ".$error->code.": ");
            break;
        }
        $msg .= ($error->message." - In line : ".$error->line." - Of file : ".$error->file."\n");

        $this->addLog($msg);
  	   }

  	   libxml_use_internal_errors(false);
  	 }

    return $result;
  }

  protected function queryResource()
  {
  	 return "//x:RESOURCE";
  }

	protected function queryResourceInfo() {

		return $this->queryResource()."/x:INFO";
	}

  protected function queryTable()
  {
  	 return $this->queryResource()."/x:TABLE";
  }

  protected function queryDescription()
  {
  	 return $this->queryTable()."/x:DESCRIPTION";
  }

  protected function queryFields()
  {
  	 return $this->queryTable()."/x:FIELD";
  }

  protected function queryField($field_id)
  {
  	 return $this->queryFields()."[@ID='".$field_id."']";
  }

  protected function queryFieldByName($field_id)
  {
  	 return $this->queryFields()."[@name='".$field_id."']";
  }
  protected function queryFieldDescription($field_id)
  {
  	 return $this->queryField($field_id)."/x:DESCRIPTION";
  }

  protected function queryData()
  {
  	 return $this->queryTable()."/x:DATA";
  }

  protected function queryTableData()
  {
  	 return $this->queryData()."/x:TABLEDATA";
  }

  protected function queryTR()
  {
  	 return $this->queryTableData()."/x:TR";
  }