<?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
		)
	);
	$context = stream_context_create($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";
  }

	protected function queryBinaryData() {
		return $this->queryData()."/x:BINARY";

	}

	protected function queryStream() {
		return $this->queryBinaryData()."/x:STREAM";

	}

  //

  public function getVersion()
  {
  	 if (!$this->xml)
  	 		return '';
  	 $root = $this->xml->documentElement;

  	 return $root->getAttribute('version');
  }

  public function getDescription()
  {
  	 if (!$this->xp)
  	   return '';

  	 $desc = $this->xp->query($this->queryDescription());

  	 if ($desc->length < 1)
  	   return '';

  	 return $desc->item(0)->nodeValue;
  }

  public function isData()
  {
    $trs =  $this->xml->getElementsByTagName('TR');
    if ($trs->length > 0) return true;

    return false;
  }

  public function getFirstTR()
  {
  	 if (!$this->xp)
  	   return NULL;

  	 /*$trs = $this->xp->query($this->queryTR());

  	 if ($trs->length < 1)
  	   return NULL;

  	 return $trs->item(0);*/

  	 $tabledatas = $this->xp->query($this->queryTableData());

  	 if ($tabledatas->length < 1)
  	   return NULL;

  	 $tabledata = $tabledatas->item(0);

  	 $node = $tabledata->firstChild;

  	 while($node && ($node->nodeType != 1) && ($node->nodeName != "TR"))
      $node = $node->nextSibling;

    return $node;
  }

  public function getNextTR($tr)
  {
  	 if (!$this->xp)
  	   return NULL;

    while($tr->nextSibling && ($tr->nextSibling->nodeType != 1) && ($node->nodeName != "TR"))
      $tr = $tr->nextSibling;
				return $tr->nextSibling;
  }

  public function getTDValueByFieldIndex($tr,$field_index)
  {
  	 if (!$this->xp)
  	   return NULL;

  	 $tds = $tr->getElementsByTagName("TD");

  	 if (($tds->length < 1) || ($field_index >= $tds->length))
  	   return NULL;

  	 return $tds->item($field_index)->nodeValue;
  }

  protected function isTimeField($field)
  {
    if (!$this->xp)
  	   return FALSE;

  	 return (($field->getAttribute("ucd") == "time.epoch") && ($field->getAttribute("xtype") == "dateTime"));
  }

  public function getTimeFieldIndex()
  {
  	 if (!$this->xp)
  	   return -1;

  	 $fields = $this->xp->query($this->queryFields());

  	 if ($fields->length < 1)
  	   return -1;

  	 for ($i = 0; $i < $fields->length; $i++)
  	   if ($this->isTimeField($fields->item($i)))
  	     return $i;

  	 return -1;
  }

	protected function getFieldByID($field_id)
	{
		if (!$this->xp)
			return NULL;

		$fields = $this->xp->query($this->queryFields());

		if ($fields->length < 1)
			return NULL;

		foreach ($fields as $field)
			if ($field->getAttribute("ID") == $field_id)
				return $field;

		return NULL;
	}

	protected function getFieldByName($field_id)
	{
		if (!$this->xp)
			return NULL;

		$fields = $this->xp->query($this->queryFieldByName($field_id));

		if ($fields->length < 1)
			return NULL;

		foreach ($fields as $field)
			if ($field->getAttribute("name") == $field_id)
			return $field;

		return NULL;

	}

	protected function checkIDAttribute()
	{

		$fields = $this->xml->getElementsByTagName('FIELD');
		$i = 0;
		foreach ($fields as $field)
		{
			$i++;
			if (!$field->hasAttribute("ID"))
			{
				$field->setAttribute("ID", "col".$i);
			}
		}
		$this->xml->saveXML();
	}

  public function getFieldIndexByID($field_id)
  {
  	 if (!$this->xp)
  	   return -1;

  	 $fields = $this->xp->query($this->queryFields());

  	 if ($fields->length < 1)
  	   return -1;

  	 for ($i = 0; $i < $fields->length; $i++)
  	   if ($fields->item($i)->getAttribute("ID") == $field_id)
  	     return $i;

  	 return -1;
  }

  public function getStartStop()

  {
  	 if (!$this->xp)
  	   return '0 0';

    $timeIndex = $this->getTimeFieldIndex();
    if ($timeIndex < 0)
      return '0 0';

    $tr = $this->getFirstTR();

    if (!$tr)
      return '0 0';

    $start = $this->getTDValueByFieldIndex($tr,$timeIndex);

    $stop = $start;
    while ($tr)
    {
      $stop = $this->getTDValueByFieldIndex($tr,$timeIndex);
      $tr = $this->getNextTR($tr);
    }

    if (!$start)
      $start = 0;
    else
      $start = strtotime($start);

    if (!$stop)
      $stop = 0;
    else
      $stop = strtotime($stop);

    return $start." ".$stop;

  }

	public function getFieldInfoByID($field_id)
	{
		if (!$this->xp)
			return array("id"    => $field_id, "error" => "No file loaded");

		$field = $this->getFieldByID($field_id);

		if (!$field)
			$field = $this->getFieldByName($field_id);

		if (!$field)
			return array("id" => $field_id, "error" => "This field doesn't exist");

		return $this->getFieldInfo($field);
	}

	/** Get the size of a row according to datatype array length. */

	private function get_row_size($field_node) {
		$datatype = $field_node->getAttribute("datatype");

		if($datatype == 'boolean') {
			return 1;
		}

		switch($datatype) {

			case 'unsignedByte':
			case 'char':
				$block_size = 1;
				break;
			case 'unicodeChar':
			case 'short':
				$block_size = 2;
				break;
			case 'int':
			case 'float':
				$block_size = 4;
				break;
			case 'long':
			case 'double':
			case 'float_complex':
				$block_size = 8;
				break;
			case 'double_complex':

				$block_size = 16;

			default:
				$block_size = 0;
				break;
		}

		if($field_node->getAttribute("arraysize") == NULL) {
			$array_size = $block_size;
		} else if("*" == $field_node->getAttribute("arraysize")) {

			$array_size = unpack("Ns", substr($this->stream, $this->c, 4))["s"] * $block_size;

			$this->c+=4;
		} else {
			$array_size = (int)($field_node->getAttribute("arraysize")) * $block_size;
		}
		return $array_size;
	}

	/** Get the VOTable stream content.*/

	public function parseStream() {

		if (! $this->isValidSchema()) {

			error_log('There is an error on the VOTable: ' . $this->votable_error);

			return null;

		}

		$data = Array();
		$fields = $this->xp->query($this->queryFields());

		$resource = $this->xp->query($this->queryResource());

		$nb_columns = $fields->length;
		$row = Array();
		$n_value = 0; // index of current value
		$this->c = 0; // initialize cursor position.
		$query_stream = $this->xp->query($this->queryStream())->item(0);

		if($query_stream == NULL) {
			$this->votable_error = "There is no STREAM node in the VOTable file.";

			return null;

		}

		$this->stream = base64_decode($query_stream->textContent);

		$stream_len = strlen($this->stream);

		if($stream_len == 0) {

			$this->votable_error = "no result";

			return null;

		}

		while($this->c < strlen($this->stream)) {
			$col_id = $n_value % $nb_columns;

			$field_node = $fields->item($col_id);

			if($col_id == 0) {
				$row = Array();
			}
			$row[$field_node->getAttribute("ID")] = $this->process_datablock($field_node);
			if($col_id == $nb_columns-1) {
				array_push($data, $row);

			}

			$n_value+=1;

		}

		return $data;
	}

	private function JDTodate($jd) {
		list($month, $day, $year) = split('/', JDToGregorian($jd));
		return "$day/$month/$year";
	}

	private function process_datablock($field_node) {
		$data_type = $field_node->getAttribute("datatype");
		$row_size = $this->get_row_size($field_node);

		$substr = substr($this->stream, $this->c, $row_size);

		switch ($data_type) {
			case 'boolean':
			case 'unsignedByte':

				$b = $substr;

				$res = $b == 'T' || $b == 't' || $b == '1';

				break;
			case 'char':

				$res = $row_size !=0 ? utf8_encode($substr) : NULL;

			case 'unicodeChar':

				$res = $row_size !=0 ? utf8_encode(str_replace("\0", '', $substr)) : NULL;

				break;
			case 'short':

				$res = unpack('ss', $substr)['s'];
				$res = is_nan($res) ? NULL : $res;

				break;
			case 'int':

				$res = unpack('Ns', $substr)['s'];
				$res = is_nan($res) ? NULL : $res;

				break;
			case 'long':

				$res = unpack('Js', $substr)['s'];  // /!\ J -> PHP 5.6 only
				$res = is_nan($res) ? NULL : $res;

				break;
			case 'float':

				$res = unpack('fs', $substr)['s'];

				// If machine is little endian:
				if($this->is_little_endian) {

					$res = unpack('f1f', strrev(pack('f', $res)))['f'];

				}

				$res = is_nan($res) ? NULL : $res;

				break;
			case 'double':

				$res = unpack('ds', $substr)['s'];

				// If machine is little endian:
				if($this->is_little_endian) {

					$res = unpack('d1d', strrev(pack('d', $res)))['d'];

				}

				$res = is_nan($res) ? NULL : $res;

				break;
			default:
				$res = NULL;

				error_log("Unknown datatype: $data_type");

				break;
		}
		$this->c+=$row_size;

		return $res;

	}

	public function getFieldInfo($field)
	{
		if (!$this->xp)
			return array("id"    => $field_id, "error" => "No file loaded");

		$description = '';
		$desc = $field->getElementsByTagName("DESCRIPTION");
		if ($desc->length >= 1)
			$description = $desc->item(0)->nodeValue;

		$size = $field->getAttribute("arraysize");
		if ($size == '')
			$size = 1;
		else
			$size = intval($size);

		switch ($field->getAttribute("datatype"))
		{
			case "short" :
				$type = "SHORT";
				break;
			case "int" :
				$type = "INTEGER";
				break;
			case "long"   :
			case "double" :
				$type = "DOUBLE";
				break;
			default :

				$type = "FLOAT";

		}

		if (!$field->getAttribute("ID"))
			$id = "col".$n;

		else

			$id = $field->getAttribute("ID");

		return array("id"     => $field->getAttribute("ID"),
						"type"        => $type,
						"name"        => $field->getAttribute("name"),
						"ucd"         => $field->getAttribute("ucd"),
						"unit"        => $field->getAttribute("unit"),
						"size"        => $size,
						"description" => $description
						);
	}

  public function getFieldsInfo()
  {
   	 if (!$this->xp)
  	   return array("error" => "No file loaded");

    $fields_info = array();

  	 $fields = $this->xp->query($this->queryFields());

  	 if ($fields->length < 1)
  	   return $fields_info;

    foreach ($fields as $field)
    {
     	if ($this->isTimeField($field))
        continue;

      array_push($fields_info,$this->getFieldInfo($field));
    }

    return $fields_info;
  }

  public function getSamplings()

  {
  	 if (!$this->xp)
  	   return array("minSampling" => 0,
                   "maxSampling" => 0);

  	 $timeIndex = $this->getTimeFieldIndex();
    if ($timeIndex < 0)
      return array("minSampling" => 0,
                   "maxSampling" => 0);

    $tr = $this->getFirstTR();

    if (!$tr)
      return array("minSampling" => 0,
                   "maxSampling" => 0);

    $prevTime = 0;
    while ($tr)
    {
      $time = $this->getTDValueByFieldIndex($tr,$timeIndex);

      if ($time)
      {
        $time = strtotime($time);
        if (($prevTime > 0) && ($time-$prevTime > 0))
          $deltaT[$time-$prevTime]++;
        $prevTime = $time;
      }

      $tr = $this->getNextTR($tr);
    }

    $minSampling = +1.e31;
    $maxSampling = 0.0;

    foreach ($deltaT as $key => $value)

    {

     if ($value/count($deltaT) < 0.10)
        continue;

      if ($key < $minSampling) $minSampling = $key;
      if ($key > $maxSampling) $maxSampling = $key;
    }

    return array("minSampling" => $minSampling,
                 "maxSampling" => $maxSampling);
  }

  /*
	* Add vector data made from components to IMPEX VOT
	*/
	public function addVectorToVot($paramID, $fileName)
	{
		$argsArr = explode(',', $paramID);

		$fields = $this->xml->getElementsByTagName('FIELD');
		$table = $this->xml->getElementsByTagName('TABLE')->item(0);
		$data = $this->xml->getElementsByTagName('DATA')->item(0);

		$i=0;

		$find = false;

		foreach ($fields as $field)

		{

			if ($field->getAttribute('name') == $argsArr[0])

			{

				$unit = $field->getAttribute('unit');
				$ucd  = $field->getAttribute('ucd');
				$datatype  = $field->getAttribute('datatype');
				$firstTD = $i;
				$find = true;
				break;
			}

			$i++;

		}

		if ($find)

		{

			$new_field = $this->xml->createElement('FIELD');
			$new_field->setAttribute('ID', $paramID);
			$new_field->setAttribute('name', $paramID);
			$new_field->setAttribute('datatype', $datatype);
			$new_field->setAttribute('arraysize', '3');
			$new_field->setAttribute('unit', $unit);

			$new_field->setAttribute('ucd', $ucd);
			$colN = $fields->length + 1;

			$new_field->setAttribute('ID', 'col'.$colN);

			$table->insertBefore($new_field,$data);

			$trs = $this->xml->getElementsByTagName('TR');
			foreach($trs as $tr)
			{
				$tds = $tr->getElementsByTagName('TD');
				$value = trim($tds->item($firstTD)->nodeValue).' '.trim($tds->item($firstTD + 1)->nodeValue).' '.trim($tds->item($firstTD + 2)->nodeValue);
				$td = $this->xml->createElement('TD', $value);
				$tr->appendChild($td);
			}

			$this->xml->save($fileName);

		}

	}

}

?>