<?php
/**
 * DigiMinaItemMultipleResponse class
 *
 * @package Digimina 
 */
class DigiMinaItemMultipleResponse extends DigiMinaItem {

    /**
     * Initialize
     *
     * @return void
     */
	protected function initializeAttributes() {
		parent::initializeAttributes();
		$this->itemtype = "multipleResponse";
    }

    /**
     * Build From XML
     *
     * @param DOMNode $resource_dom Item resource tag from manifest xml
     * @param DOMDocument $item_dom Item DOM document
     *
     * @return void
     */
    function buildFromXML($resource_dom, $item_dom) {
        parent::buildFromXML($resource_dom, $item_dom);
        $title = $this->getTitleFromXML($item_dom);
        $this->title = $title;
        $this->itembody = $this->getItemBodyFromXML($item_dom);
        $choices = $this->getChoicesFromXML($item_dom);
        $this->choices = serialize($choices);
        $this->correct = $this->getCorrectChoices($item_dom);
    }

    /**
     * Return array of choices retrieved from xml
     *
     * @param DOMDocument $dom Item DOM document
     *
     * @return array
     */
    function getChoicesFromXML($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"] = $choice_text;
            $score = $this->findChoiceScore($dom, $identifier);
            $new_choices[$identifier]["score"] = $score;
        }
        return $new_choices;
    }

    /**
     * Return given choice score from xml
     *
     * @param DOMDocument $dom Item DOM document
     * @param string $identifier Choice identifier
     *
     * @return float
     */
    function findChoiceScore($dom, $identifier) {
        $map_entries = $dom->getElementsByTagName("mapEntry");
        for ($i=0; $i<$map_entries->length; $i++) {
            $map_entry = $map_entries->item($i);
            $map_key = $map_entry->getAttribute("mapKey");
            if ($identifier == $map_key) {
                return $map_entry->getAttribute("mappedValue");
            }
        }
        return 0;
    }

    /**
     * Return correct choices from xml
     *
     * @param DOMDocument $dom Item DOM document
     *
     * @return array Correct choices array
     */
    function getCorrectChoices($dom) {
        $correct_choices = array();
        $correct_response = $dom->getElementsByTagName("correctResponse")->item(0);
        $values = $correct_response->getElementsByTagName("value");
        for ($i=0; $i<$values->length; $i++) {
            $value = $values->item($i);
            $correct = $this->findNodeText($value);
            $correct_choices []= $correct;
        }
        return $correct_choices;
    }

    /**
     * Returns true or false based on given answer
     *
     * @param array chosen User answer
     * @return bool
     *
     */
    function answer($chosen) {
        if ($chosen == $this->correct) {
            return true;
        }
        return false;
    }

}