<?php

class SurveyAnswerRDFReader extends SurveyRDFReader
{	
	protected $tempModel;
	protected $answerPath;
	
    public function __construct($surveyUID)
    {
        parent::__construct($surveyUID);
		
		// Create empty MemModel
		$factory = new ModelFactory();
		$this->tempModel = $factory->getDefaultModel();
		$this->answerPath = 'data/surveys/answers_'.$this->surveyUID;
	}
	
	public function loadSurvey()
	{
		parent::loadSurvey();		
		
	}
	
	public function getAnswerByQuestion($questionID)
	{
		$this->tempModel->loadModel($this->model);
		
		$answers = array();
		
		if($handle = opendir($this->answerPath))
		{
			while (false !== ($file = readdir($handle))) {
				if(strstr($file, 'answer_'))
					$answers[] = substr($file,0,strlen($file)-4);
			}
		}
		
		foreach($answers as $answer)
		{
			$this->tempModel->load($this->answerPath.'/'.$answer);
		}
		
		$this->tempModel->visualize();
	
		$querystring = '
			PREFIX 	predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
			PREFIX	resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
			SELECT 	?answered 
			WHERE 	
			{
				_question	predicates:resource_type	resources:question ;
							predicates:uid				"'.$questionID.'"	;
							predicates:answered 		?answered 	
			}';
			
		$result = $this->tempModel->sparqlQuery($querystring);
		
		$this->tempModel->close();		

		$this->tempModel->visualize();
				
		return $result;
	}
	
	public function getAnswerByRespondent($respondentID)
	{
		$this->tempModel->loadModel($this->model);
		
		$this->tempModel->load($this->answerPath . '/$answer_' . $respondentID);
		
		$this->tempModel->visualize();
	
		$querystring = '
			PREFIX 	predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
			PREFIX	resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
			SELECT 	?answered 
			WHERE 	
			{
				_question	predicates:resource_type	resources:question ;
							predicates:answered 		?answered 	
			}';
			
		$result = $this->tempModel->sparqlQuery($querystring);
		
		$this->tempModel->close();		

		$this->tempModel->visualize();
				
		return $result;
	}
	
	public function getAnswerByRespondentAndQuestion($respondentID,$questionID)
	{
		$this->tempModel->loadModel($this->model);
				
		$this->tempModel->load($this->answerPath . '/$answer_' . $respondentID);
		
		$this->tempModel->visualize();
	
		$querystring = '
			PREFIX 	predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
			PREFIX	resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
			SELECT 	?answered 
			WHERE 	
			{
				_question	predicates:resource_type	resources:question ;
							predicates:uid				"'.$questionID.'"	;
							predicates:answered 		?answered 	
			}';
			
		$result = $this->tempModel->sparqlQuery($querystring);
		
		$this->tempModel->close();		

		$this->tempModel->visualize();
				
		return $result;
	}
}

?>