<?php

class MultipleChoice extends BaseItem {
    private $choices = array();
    private $score = 1;

    function __construct($id = NULL) {
        parent::__construct($id);
        $this->setType("multipleChoice");
        $this->setInteractionType("choiceInteraction");
        $this->setName("Multiple Choice");
        $this->setTable("multiple_choice");
        if ($id) {
            $data = $this->load($id);
            if ($data) {
                $this->setChoices(unserialize($data->choices));
                $this->setScore($data->score);
            }
        }
    }
    
    function create() {
        if ($id = parent::create()) {
            $serialized_choices = serialize($this->getChoices());
            $insert_query = "INSERT INTO " . DB_PREFIX . $this->getTable() . " (base_id, choices, score) values (".$id.", '".mysql_real_escape_string($serialized_choices)."', ".$this->getScore().")";
            $insert = query_insert($insert_query);
            return $id;
        }
        return false; 
    }
    
    function save() {
        if (parent::save()) {
            $update_query = "UPDATE " . DB_PREFIX . $this->getTable() . " SET";
            $serialized_choices = serialize($this->getChoices());
            $update_query .= " choices='".mysql_real_escape_string($serialized_choices). "',";
            $update_query .= " score=".$this->getScore();
            $update_query .= " WHERE base_id=".$this->getId();
            if (query_update($update_query))
                return $this->getId();
        }
        return false;   
    }
    
    //function copy($locked=true) {
      //  $copy = $this->create();
        /*if ($copy && $locked) {
            $lock = $this->lock($copy);
        }*/
        //return $copy;
    //}
    
    function initialiseChoices() {
        $choices = array();
        for ($i=1; $i<=4; $i++) {
            $choice_data = array();
            $choice_data["choice_text"] = "";
            $choice_data["correct"] = false;
            $choice_data["fixed"] = false;
            $choices[$i] = $choice_data;
        }
        $this->choices = $choices;
    }
    
    function answer($data) {
        $candidate = $data["candidate"];
        $chosen = $data["chosen"];
        $score = $this->calculateScore($chosen);
        $insert = query_insert("INSERT INTO " . DB_PREFIX . "multiple_choice_answers (base_id, candidate, chosen, score) VALUES (". $this->getId() .", ". $candidate .", '". $chosen ."', ". $score .")");
        return true;
    }

    function calculateScore($chosen) {
        if (!$chosen) {
            return 0;
        }
        $choices = $this->getChoices();
        $choice = $choices[$chosen];
        if ($choice["correct"]) {
            return $this->getScore();
        }
        return 0;
    }

    function getCandidateAnswer($token) {
        global $TeKe;
        $candidate_id = $TeKe->plugin->assessments->getCandidateByToken($token);
        $query = "SELECT * FROM " . DB_PREFIX . "multiple_choice_answers";
        $query .= " WHERE base_id=". $this->getId();
        $query .= " AND candidate=". $candidate_id;
        $res = query_row($query);
        return $res; 
    }

    function getCandidateAnswerForCSV($token) {
        // returns either "0," or "1," depending is answer correct or not
        $answer = $this->getCandidateAnswer($token);
        if (!($answer->chosen)) {
            return "0,";
        }
        $choices = $this->getChoices();
        $choice = $choices[$answer->chosen];
        if ($choice["correct"]) {
            return "1,";
        }
        return "0,";
    }
    
    function build($data) {
        if (parent::build($data)) {
            /*if (isset($data["table_width"])) {
                if (is_numeric($data["table_width"])) {
                    $this->setTableWidth($data["table_width"]);
                } else {
                    $this->addBuildError(_("Table width"));
                }
            }*/
            $this->saveChoices($data["choice_text"], $data["correct_choice"]);
            if (isset($data["score"]) && is_numeric($data["score"])) {
                $this->setScore($data["score"]);
            }
            if ($this->getBuildError()) {
                global $TeKe;
                $TeKe->add_system_message(_("Problems with fields") . ": " . implode(",", $this->getBuildError()), 'error');
      	        return false;    
            }
            if ($this->getId() > 0) {
                return $this->save();
            } else {
                return $this->create();
            }
        }
    }

    function saveChoices($new_choices, $correct_choice) {
        $choices = array();
        $choice_value = 0;
        foreach ($new_choices as $choice_nr => $choice) {
            if ($choice != "") {
                $choice_data = array();
                $choice_data["choice_text"] = $choice;
                if ($choice_nr == $correct_choice) {
                    $choice_data["correct"] = true;
                } else {
                    $choice_data["correct"] = false;
                }
                $choice_data["fixed"] = false;
                $choice_value++;
                $choices [$choice_value]= $choice_data;
            }
        }
        $this->choices = $choices;
    }

    function getChoices() {
        if (empty($this->choices)) {
            $this->initialiseChoices();
        }
        return $this->choices;
    }
    
    function setChoices($choices) {
        $this->choices = $choices;
    }

    function getScore() {
        return (string)(floatval($this->score));
    }

    function setScore($score) {
        $this->score = $score;
    }

    function getMaximumScore() {
        return $this->score;
    }

    function getRightChoice() {
        $choices = $this->getChoices();
        foreach ($choices as $choice_nr => $choice) {
            if ($choice["correct"] == true) {
                return $choice_nr;
            }
        }
        return false;
    }

    function setRightChoice($right_choice) {
        $this->right_choice = $right_choice;
    }

    function buildFromXML($resource_dom, $dom) {
        parent::buildFromXML($resource_dom);
        $item_body = $this->findItemBodyText($dom);
        $choices = $this->findChoices($dom);
        $correct_choice = $this->findCorrectChoice($dom);
        $this->setTitle($this->getTitleFromXML($dom));
        $this->setItemBody($item_body);
        $score = $this->findScore($dom);
        $this->setScore($score);
        $this->saveChoices($choices, $correct_choice);
        return $this->create();
    }

    function getTitleFromXML($dom) {
        $assessmentItem = $dom->getElementsByTagName("assessmentItem")->item(0);
        return $assessmentItem->getAttribute("title");
    }

    function findItemBodyText($dom) {
        $item_body = $dom->getElementsByTagName("itemBody")->item(0);
        $children = $item_body->childNodes;
        for ($i=0; $i<$children->length; $i++) {
            $item = $children->item($i);
            if ($item->nodeType != XML_TEXT_NODE && $item->nodeType != XML_CDATA_SECTION_NODE) {
                return $children->item($i)->textContent;
            }
        }
        return ""; 
    }

    function findChoices($dom) {
        $choice_interaction = $dom->getElementsByTagName("choiceInteraction")->item(0);
        $choices = $choice_interaction->getElementsByTagName("simpleChoice");
        $new_choices = array();
        for ($i=0; $i<$choices->length; $i++) {
            $choice = $choices->item($i);
            $identifier = $choice->getAttribute("identifier");
            $choice_text = $this->findNodeText($choice);
            $new_choices[$identifier] = $choice_text;
        }
        return $new_choices;
    }

    function findNodeText($node) {
        $children = $node->childNodes;
        for ($i=0; $i<$children->length; $i++) {
            $item = $children->item($i);
            if ($item->nodeType == XML_TEXT_NODE || $item->nodeType == XML_CDATA_SECTION_NODE) {
                $child_text = $children->item($i)->textContent;
                if (trim($child_text) != "") {
                    return $children->item($i)->textContent;
                }
            }
            
        }
        return "";
    }

    function findCorrectChoice($dom) {
        $correct_response = $dom->getElementsByTagName("correctResponse")->item(0);
        $value = $correct_response->getElementsByTagName("value")->item(0);
        $correct = $this->findNodeText($value);
        return $correct;
    }

    function findScore($dom) {
        $response_processing = $dom->getElementsByTagName("responseProcessing")->item(0);
        $response_if = $response_processing->getElementsByTagName("responseIf")->item(0);
        $match = $response_if->getElementsByTagName("match");
        if ($match->length > 0) {
            $base_value = $response_if->getElementsByTagName("baseValue")->item(0);
            return $base_value->textContent;
        }
        return 1;
    }

    function getXML() {
        $xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
<assessmentItem xmlns=\"http://www.imsglobal.org/xsd/imsqti_v2p1\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:schemaLocation=\"http://www.imsglobal.org/xsd/imsqti_v2p1 http://www.imsglobal.org/xsd/imsqti_v2p1.xsd\" identifier=\"".$this->getId()."\" title=\"".htmlentities($this->getTitle())."\" adaptive=\"false\" timeDependent=\"false\">\n";
        $xml .= "<responseDeclaration identifier=\"RESPONSE_".$this->getId()."\" cardinality=\"single\" baseType=\"identifier\">\n";
        $xml .= "<correctResponse>\n";
        $xml .= "<value>";
        $xml .= $this->getRightChoice();
        $xml .= "</value>\n";
        $xml .= "</correctResponse>\n";
        $xml .= "</responseDeclaration>\n";
        $xml .= "<outcomeDeclaration identifier=\"SCORE\" cardinality=\"single\" baseType=\"integer\">\n";
        $xml .= "<defaultValue>\n";
        $xml .= "<value>0</value>\n";
        $xml .= "</defaultValue>\n";
        $xml .= "</outcomeDeclaration>\n";
        $xml .= "<itemBody>\n";
        $xml .= "<p>\n<![CDATA[".$this->getItemBody()."]]>\n</p>\n";
        $xml .= "<choiceInteraction responseIdentifier=\"RESPONSE_".$this->getId()."\" shuffle=\"false\" maxChoices=\"1\">\n";
        $choices = $this->getChoices();
        foreach ($choices as $choice_nr => $choice) {
            $xml .= "<simpleChoice fixed=\"true\" identifier=\"".$choice_nr."\">\n"; 
            $xml .= "<![CDATA[" . $choice["choice_text"] . "]]>\n";
            $xml .= "</simpleChoice>\n";
        }        
        $xml .= "</choiceInteraction>\n";   
        $xml .= "</itemBody>\n";
        $xml .= $this->match_correct_xml()."\n";
        $xml .= "</assessmentItem>";
        return $xml;
    }    
}
?>