<?php

/**
 * Description of SurveyConnector
 *
 * @author jkraaijeveld
 */
class SurveyConnector extends Connector{
    protected $db;

    /**
     * Constructor for ApplicationConnector.
     */
    public function __construct()
    {
		$this->fileName = 'data/surveys/surveys.rdf';
        //Ensure the required folder for this connector exists
        if (!is_dir('data/surveys/'))
            mkdir('data/surveys/');	
    }
    
    /**
     * function get($arguments)
     * Gets the array of Survey objects belonging to arguments supplied.
     * @param type $arguments : An array containing zero or more of the following keys:
     *                          'uid', 'title', 'description', 'questions'
     * Note: questions has to be an array of question IDs (codes) for this filter to work.
     */
    public function get($arguments)
    {
        $this->load();
        
        //Build the query string
        $querystring = '
            PREFIX  predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
            PREFIX  resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
            SELECT DISTINCT ?uid, ?title, ?description, ?creator
            WHERE
            {
                _survey     predicates:resource_type    resources:survey ;
                predicates:uid ?uid ;
                predicates:title ?title ;
				predicates:description ?description ;
				predicates:creator ?creator ;
				' . $this->createArguments($arguments) . '
            }';
        
        //Query the model
        $results = $this->model->sparqlQuery($querystring);
        
        //Create the corresponding Survey objects
        $surveys = array();
        if(!empty($results))
        {
            $this->db = new DatabaseInterface();
            foreach($results as $result)
            {
				$questions = $this->getQuestions($result['?uid']->label);
				$creator = $this->db->get("user", array("uid" => $result['?creator']->label));
                $surveys[] = new Survey($result['?uid']->label, $result['?title']->label, $result['?description']->label, $creator[0], $questions);
            }
        }
        return $surveys;
    }
    
    /**
     * Gets the questions corresponding to the survey
     * @param type $uid : The uid for which the questions should be gotten.
     */
    private function getQuestions($uid)
    {
		$result = $this->model->findRegex("[(".$uid.")]", "[(has_question)]", null);
		$iterator = $result->getStatementIterator();
		$questions = array();
		while($iterator->hasNext())
		{
			$element = $iterator->next();
			$result = $this->db->get("question", array("code" => $element->getLabelObject()));
			$questions[] = $result[0];
		}
		return $questions;
    }
    
    /**
     * Saves the given Survey object.
     * @param type $rToolObject : The ResearchToolObject to be saved.
     */
    public function set($rToolObject)
    {
        $this->load();
        
        $resourceSurvey = new Resource(SURVEY.'/'.$rToolObject->uid);
        //Remove the old value stored with the given id
        $this->model->subtract($this->model->find($resourceSurvey, null, null));
        
        $resourceSurveyType = new Resource(SURVEY);
        $predicateRType = new Resource(RTYPE);
        $this->model->add(new Statement($resourceSurvey,$predicateRType,$resourceSurveyType));

        $predicateUniqueID = new Resource(UID);
        $literalSurveyID = new Literal($rToolObject->uid);
        $this->model->add(new Statement($resourceSurvey,$predicateUniqueID,$literalSurveyID));

        $predicateTitle = new Resource(TITLE);		
        $surveyTitle = new Literal($rToolObject->title);
        $this->model->add(new Statement($resourceSurvey,$predicateTitle,$surveyTitle));		

        $predicateDescription = new Resource(DESCRIPTION);
        $surveyDescription = new Literal($rToolObject->description);
        $this->model->add(new Statement($resourceSurvey,$predicateDescription,$surveyDescription));
        
		$predicateCreator = new Resource(CREATOR);
		$surveyCreator = new Literal($rToolObject->creator->uid);
		$this->model->add(new Statement($resourceSurvey, $predicateCreator, $surveyCreator));

        if(isset($rToolObject->questions))
        {
            foreach($rToolObject->questions as $question)
            {
                $questionUid = new Literal($question->uid);
                $predicateQuid = new Resource(HAS_QUESTION);
                $this->model->add(new Statement($resourceSurvey,$predicateQuid,$questionUid));
            }
        }
        $this->save();
    }
}

?>