source: Dev/trunk/classes/Session.php @ 186

<?php
/**
 * Description of Session
 *
 * @author jkraaijeveld
 */

class Session extends ResearchToolObject
{
        public $title;
        public $creator;
        public $datetime;
        public $pipeline;
        public $answersets;

        
        /**
         * Constructor for a Session object
         * @param type $uid
         * @param type $title
         * @param type $creator
         * @param type $datetime
         * @param type $pipeline
         */
        public function __construct($uid = null, $title = null, $creator = null, $datetime = null, $pipeline = null, $answersets = null)
        {
                if(!isset($uid))
                {
                        $uid = md5(uniqid(rand(), true));
                }
                $this->uid = $uid;
                $this->title = $title;
                $this->creator = $creator;
                $this->datetime = $datetime;
                $this->pipeline = $pipeline;
                $this->answersets = $answersets;
        }

        /*
         * function evaluate(()
         * Evaluates all the references of this object.
         */
        public function evaluate()
        {
                $dbi = new DatabaseInterface();
                if(is_string($this->creator))
                {
                        $result = $dbi->get("user", array("uid" => $this->creator));
                        if(!isset($result[0]))
                                return false;
                        $this->creator = $result[0];
                }
                if(!empty($this->pipeline) && is_string($this->pipeline[0]))
                {
                        $newPipeline = array();
                        foreach($this->pipeline as $element)
                        {
                                //Check if the element's UID can be found in surveys, if not: 
                                //Check applications. If it isn't in either: invalid reference.
                                $result = $dbi->get("survey", array("uid" => $element));
                                if(!isset($result[0]))
                                        $result = $dbi->get("application", array("uid" => $element));
                                if(!isset($result[0]))
                                        return false;
                                $newPipeline[] = $result[0];
                        }
                        $this->pipeline = $newPipeline;
                }
                if(!empty($this->answersets) && is_string($this->answersets[0]))
                {
                        $newAnswerSets = array();
                        foreach($this->answersets as $element)
                        {
                                $result = $dbi->get("answerset", array("uid" => $element));
                                if(!isset($result[0]))
                                        return false;
                                $newAnswerSets[] = $result[0];
                        }
                        $this->answersets = $newAnswerSets;
                }
                return true;
        }

        /**
         * function toSPSS
         * @param type $location
         * Writes an SPSS parseable file at the given location, named '$datetime_$title.txt'
         * One big note about toSPSS: If this session contains multiple instances of THE SAME Survey,
         * the world burns, people die, etcetera. (or, in a more fortunate case, the latest values
         * are written to the file whilst the others get lost.
         */
        public function toSPSS($location)
        {
                $this->evaluate();
                if(!is_dir($location))
                {
                        mkdir($location);
                }
                //Create the filename, open the file at the given location
                $fileName = $this->datetime->format("d-m-Y") . "_" . $this->title . ".txt";

                //Make a list of all 'column headers', e.g. "respondent" and all the question codes.
                $headers = array();
                $headers[] = "respondent";
                foreach ($this->pipeline as $element)
                {
                        if(get_class($element) == "Survey")
                        {
                                $element->evaluate();
                                foreach($element->questions as $question)
                                {
                                        //TODO: This might need fixing after lazy initialization refactoring.
                                        $headers[] = $element->title . '_' . $question->uid;
                                }
                        }
                }
                //Return if there are no surveys.
                if(count($headers) < 2)
                        return;
                
                //Get the answers for all respondents
                $answers = $this->getAnswers($headers);

                //Create the strings and write to file.
                $headerString = "";
                foreach($headers as $headerElement)
                {
                        $headerString = $headerString . $headerElement . "\t";
                }
                $fileHandler = fopen($location . '/' . $fileName, 'w') or die("File in use");
                fwrite($fileHandler, $headerString . "\n");
                foreach($answers as $entry)
                {
                        $entryString = "";
                        //PHP doesn't automatically sort the indices so I have to do it myself
                        //Entry elements can now be printed in order to match the headers
                        for ($i = 0; $i < count($headers); $i++)
                        {
                                if(in_array($i, array_keys($entry)))
                                        $entryString = $entryString . $entry[$i] . "\t";        
                                else
                                        $entryString = $entryString . "\t";
                        }
                        fwrite($fileHandler, $entryString . "\n");      
                }
        }

        /*
         * function getAnswers
         * @param type $headers
         * Based on the questions specified in the headers array, matches the answers of every
         * respondent to the correct questions and returns an array containing a list of answers per 
         * respondent
         */
        private function getAnswers($headers)
        {
                //Add the answers per survey per respondent. Requires some extra looping to assure proper ordering.
                //Keeps a list of respondents which have already been used. If an answerset exists for a respondent which
                //already exists within the answers-array, use the index of the respondent. Else: make a new row.
                $respondentsUsed = array();
                $answers = array();
                foreach($this->answersets as $answerset)
                {
                        $entryIndex;
                        if(in_array($answerset->respondent->name, $respondentsUsed))
                        {
                                $entryIndex = array_search($answerset->respondent->name, $respondentsUsed);
                                $entry = $answers[$entryIndex];
                        }
                        else
                        {
                                $entry = array();
                                $entry[0] = $answerset->respondent->name;
                                $entryIndex = count($respondentsUsed);
                                $respondentsUsed[] = $answerset->respondent->name;
                        }
                        foreach ($answerset->answers as $answer)
                        {
                                $index = array_search($answerset->survey->title . '_' . $answer->question->uid, $headers);
                                //Index has to be a good number, else the answer doesn't belong in this session
                                //Causes might be a missing question or having a wrong survey
                                if($index != 0)
                                {
                                        $value = "";
                                        foreach ($answer->values as $val)
                                        {
                                                $value = $value . $val . ",";
                                        }
                                        //We all hate trailing commas
                                        if (strlen($value) > 0) { $value = substr($value, 0, strlen($value)-1); }
                                        $entry[$index] = $value;
                                }
                        }
                        $answers[$entryIndex] = $entry;
                }
                return $answers;
        }

}       


?>