<?php

// Survey database interface class as intermediate for storing data from the site to the RDF database 
require_once 'rdfConstants.php';
// Include RAP Library to write RDF files
include(RDFAPI_INCLUDE_DIR . "RDFAPI.php");

/**
 * Description of ApplicationConnector
 *
 * @author jkraaijeveld
 */
class ApplicationConnector implements IConnector{
    
    protected $model;
    protected $fileName = 'data/applications/applications.rdf';

    /**
     * Constructor for ApplicationConnector.
     */
    public function __construct()
    {
        //Ensure the required folder for this connector exists
        if (!is_dir('data/applications/'))
            mkdir('data/applications/');	
    }
    
    /**
     * function load()
     * Loads the file into the standard MemModel.
     */
    public function load() {
        //Get the Memory Model from the ModelFactory
        $this->model = ModelFactory::getDefaultModel();
        
        //Ensure the required file exists before loading
        if(file_exists($this->fileName))
            $this->model->load($this->fileName);
    }
    
    /**
     * function save()
     * Saves the MemModel into the given file.
     */
    public function save() {
        $this->model->saveAs($this->fileName,'rdf'); 
    }
    
    /**
     * function get($arguments)
     * Gets the array of Application objects belonging to arguments supplied.
     * @param type $arguments : An array containing zero or more of the following keys:
     *                          'uid', 'title', 'description', 'style'
     */
    public function get($arguments) {
        $this->load();
        //Determine which arguments are supplied
        $keys = array_keys($arguments);
        //Set default values for arguments
        $uid = "?uid"; $title = "?title"; $description = "?description"; $style = "?style";
        //Set the arguments if they are supplied
        if(in_array("uid", $keys))
            $uid = "\"".$arguments["uid"]."\"";
        if(in_array("title", $keys))
            $title = '\''.$arguments["title"].'\'';
        if(in_array("description", $keys))
            $description = "\"".$arguments["description"]."\"";
        if(in_array("style", $keys))
            $style = "\"".$arguments["style"]."\"";    

        //Create the querystring 
        $querystring = '
            PREFIX  predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
            PREFIX  resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
            SELECT ?uid, ?title, ?description, ?style
            WHERE 	
            {
                    _application	predicates:resource_type	resources:application ;
					predicates:uid ?uid ;
					predicates:title ?title ;
					predicates:description ?description ;
					predicates:style ?style ;
                     			predicates:uid ' . $uid . ' 
					predicates:title ' . $title . ' 
					predicates:description ' . $description . ' 
					predicates:style ' . $style . '
            }';

        //Query the model
        $results = $this->model->sparqlQuery($querystring);
        $applications = array();
        if(!empty($results))
        {
            //Run over all results and create appropriate Application objets
            foreach($results as $result)
            { 
                    $applications[] = new Application($result['?uid']->label, $result['?title']->label, $result['?description']->label, $result['?style']->label);
            }
        }
        return $applications;
    }
    
    /**
     * function set()
     * Finds the required databaseentry matching the given object and removes
     * it from the rdf file. Then adds the new RDF entry matching the object.
     * @param type $rToolObject: The ResearchToolObject to be saved. 
     */
    public function set($rToolObject)
    {
        $this->load();
        $resourceApplication = new Resource(APPLICATION.'/'.$rToolObject->uid);
        //Remove the old value stored with the given id
        $this->model->subtract($this->model->find($resourceApplication, null, null));

        //Add the new statements to the model
        $resourceApplicationType = new Resource(APPLICATION);
        $predicateRType = new Resource(RTYPE);
        $this->model->add(new Statement($resourceApplication,$predicateRType,$resourceApplicationType));
		
        $literalApplicationID = new Literal($rToolObject->uid);
        $predicateUniqueID = new Resource(UID);
        $this->model->add(new Statement($resourceApplication,$predicateUniqueID,$literalApplicationID));

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

        $applicationDescription = new Literal($rToolObject->description);
        $predicateDescription = new Resource(DESCRIPTION);
        $this->model->add(new Statement($resourceApplication,$predicateDescription,$applicationDescription));

        $applicationStyle = new Literal($rToolObject->style);
        $predicateStyle = new Resource(STYLE);
        $this->model->add(new Statement($resourceApplication,$predicateStyle,$applicationStyle));
		
	$this->save();
    }
}

?>