Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * @package   moodlecore

 * @subpackage backup-imscc

 * @copyright 2009 Mauro Rondinelli (mauro.rondinelli [AT] uvcms.com)

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

defined('MOODLE_INTERNAL') or die('Direct access to this script is forbidden.');

require_once($CFG->dirroot . '/backup/cc/entities.class.php');

require_once($CFG->dirroot . '/backup/cc/entity.label.class.php');

require_once($CFG->dirroot . '/backup/cc/entity.resource.class.php');

require_once($CFG->dirroot . '/backup/cc/entity.forum.class.php');

require_once($CFG->dirroot . '/backup/cc/entity.quiz.class.php');

class cc2moodle {

    const CC_TYPE_FORUM              = 'imsdt_xmlv1p0';

    const CC_TYPE_QUIZ               = 'imsqti_xmlv1p2/imscc_xmlv1p0/assessment';

    const CC_TYPE_QUESTION_BANK      = 'imsqti_xmlv1p2/imscc_xmlv1p0/question-bank';

    const CC_TYPE_WEBLINK            = 'imswl_xmlv1p0';

    const CC_TYPE_WEBCONTENT         = 'webcontent';

    const CC_TYPE_ASSOCIATED_CONTENT = 'associatedcontent/imscc_xmlv1p0/learning-application-resource';

    const CC_TYPE_EMPTY              = '';

    public static $restypes = array('associatedcontent/imscc_xmlv1p0/learning-application-resource', 'webcontent');

    public static $forumns  = array('dt' => 'http://www.imsglobal.org/xsd/imsdt_v1p0');

    public static $quizns   = array('xmlns' => 'http://www.imsglobal.org/xsd/ims_qtiasiv1p2');

    public static $resourcens = array('wl' => 'http://www.imsglobal.org/xsd/imswl_v1p0');

    /**

     *

     * @return array

     */

    public static function getquizns() {

        return static::$quizns;

    }

    /**

     *

     * @return array

     */

    public static function getforumns() {

        return static::$forumns;

    }

    /**

     *

     * @return array

     */

    public static function getresourcens() {

        return static::$resourcens;

    }

    public static function get_manifest($folder) {

        if (!is_dir($folder)) {

            return false;

        }

        // Before iterate over directories, try to find one manifest at top level

        if (file_exists($folder . '/imsmanifest.xml')) {

            return $folder . '/imsmanifest.xml';

        }

        $result = false;

        try {

            $dirIter = new RecursiveDirectoryIterator($folder, RecursiveDirectoryIterator::KEY_AS_PATHNAME);

            $recIter = new RecursiveIteratorIterator($dirIter, RecursiveIteratorIterator::CHILD_FIRST);

            foreach ($recIter as $info) {

                if ($info->isFile() && ($info->getFilename() == 'imsmanifest.xml')) {

                    $result = $info->getPathname();

                    break;

                }

            }

        } catch (Exception $e) {}

        return $result;

    }

    public static $instances = array();

    public static $manifest;

    public static $path_to_manifest_folder;

    public static $namespaces = array('imscc'    => 'http://www.imsglobal.org/xsd/imscc/imscp_v1p1',

                                      'lomimscc' => 'http://ltsc.ieee.org/xsd/imscc/LOM',

                                      'lom'      => 'http://ltsc.ieee.org/xsd/LOM',

                                      'voc'      => 'http://ltsc.ieee.org/xsd/LOM/vocab',

                                      'xsi'      => 'http://www.w3.org/2001/XMLSchema-instance',

                                      'cc'       => 'http://www.imsglobal.org/xsd/imsccauth_v1p0');

    function __construct($path_to_manifest) {

        static::$manifest = new DOMDocument();

        static::$manifest->validateOnParse = false;

        static::$path_to_manifest_folder = dirname($path_to_manifest);

        static::log_action('Proccess start');

        static::log_action('Load the manifest file: ' . $path_to_manifest);

        if (!static::$manifest->load($path_to_manifest, LIBXML_NONET)) {

            static::log_action('Cannot load the manifest file: ' . $path_to_manifest, true);

        }

    }

    public function is_auth() {

        $xpath = static::newx_path(static::$manifest, static::$namespaces);

        $count_auth = $xpath->evaluate('count(/imscc:manifest/cc:authorizations)');

        if ($count_auth > 0) {

            $response = true;

        } else {

            $response = false;

        }

        return $response;

    }

    protected function get_metadata($section, $key) {

        $xpath = static::newx_path(static::$manifest, static::$namespaces);

        $metadata = $xpath->query('/imscc:manifest/imscc:metadata/lomimscc:lom/lomimscc:' . $section . '/lomimscc:' . $key . '/lomimscc:string');

        $value = !empty($metadata->item(0)->nodeValue) ? $metadata->item(0)->nodeValue : '';

        return $value;

    }

    public function generate_moodle_xml() {

        global $CFG, $OUTPUT;

        $cdir = static::$path_to_manifest_folder . DIRECTORY_SEPARATOR . 'course_files';

        if (!file_exists($cdir)) {

            mkdir($cdir, $CFG->directorypermissions, true);

        }

        $sheet_base = static::loadsheet(SHEET_BASE);

        // MOODLE_BACKUP / INFO / DETAILS / MOD

        $node_info_details_mod = $this->create_code_info_details_mod();

        // MOODLE_BACKUP / BLOCKS / BLOCK

        $node_course_blocks_block = $this->create_node_course_blocks_block();

        // MOODLE_BACKUP / COURSES / SECTIONS / SECTION

        $node_course_sections_section = $this->create_node_course_sections_section();

        // MOODLE_BACKUP / COURSES / QUESTION_CATEGORIES

        $node_course_question_categories = $this->create_node_question_categories();

        // MOODLE_BACKUP / COURSES / MODULES / MOD

        $node_course_modules_mod = $this->create_node_course_modules_mod();

        // MOODLE_BACKUP / COURSE / HEADER

        $node_course_header = $this->create_node_course_header();

        // GENERAL INFO

        $filename = optional_param('file', 'not_available.zip', PARAM_RAW);

        $filename = basename($filename);

        $www_root = $CFG->wwwroot;

        $find_tags = array('[#zip_filename#]',

                           '[#www_root#]',

                           '[#node_course_header#]',

                           '[#node_info_details_mod#]',

                           '[#node_course_blocks_block#]',

                           '[#node_course_sections_section#]',

                           '[#node_course_question_categories#]',

                           '[#node_course_modules#]');

        $replace_values = array($filename,

                                $www_root,

                                $node_course_header,

                                $node_info_details_mod,

                                $node_course_blocks_block,

                                $node_course_sections_section,

                                $node_course_question_categories,

                                $node_course_modules_mod);

        $result_xml = str_replace($find_tags, $replace_values, $sheet_base);

        // COPY RESOURSE FILES

        $entities = new entities();

        $entities->move_all_files();

        if (array_key_exists("index", self::$instances)) {

            if (!file_put_contents(static::$path_to_manifest_folder . DIRECTORY_SEPARATOR . 'moodle.xml', $result_xml)) {

                static::log_action('Cannot save the moodle manifest file: ' . static::$path_to_manifest_folder . DIRECTORY_SEPARATOR . 'moodle.xml', true);

            } else {

                $status = true;

            }

        } else {

            $status = false;

            echo $OUTPUT->notification('The course is empty');

            static::log_action('The course is empty', false);

        }

        return $status;

    }

    protected function get_sections_numbers($instances) {

        $count = 0;

        if (array_key_exists("index", $instances)) {

            foreach ($instances["index"] as $instance) {

                if ($instance["deep"] == ROOT_DEEP) {

                    $count++;

                }

            }

        }

        return $count;

    }

    protected function create_node_course_header() {

        $node_course_header = '';

        $sheet_course_header = static::loadsheet(SHEET_COURSE_HEADER);

        $course_title = trim($this->get_metadata('general', 'title'));

        $course_title = empty($course_title) ? 'Untitled Course' : $course_title;

        $course_description = $this->get_metadata('general', 'description');

        $section_count = $this->get_sections_numbers(static::$instances) - 1;

        if ($section_count == -1) {

            $section_count = 0;

        }

        if (empty($course_title)) {

            $this->log_action('The course title not found', true);

        }

        $course_short_name = $this->create_course_code($course_title);

        $find_tags = array('[#course_name#]',

                           '[#course_short_name#]',

                           '[#course_description#]',

                           '[#date_now#]',

                           '[#section_count#]');

        $replace_values = array(entities::safexml($course_title),

                                entities::safexml($course_short_name),

                                entities::safexml($course_description),

                                time(),

                                $section_count);

        $node_course_header = str_replace($find_tags, $replace_values, $sheet_course_header);

        return $node_course_header;

    }

    protected function create_node_question_categories() {

        $quiz = new cc_quiz();

        static::log_action('Creating node: QUESTION_CATEGORIES');

        $node_course_question_categories = $quiz->generate_node_question_categories();

        return $node_course_question_categories;

    }

    protected function create_node_course_modules_mod() {

        $labels = new cc_label();

        $resources = new cc_resource();

        $forums = new cc_forum();

        $quiz = new cc_quiz();

        static::log_action('Creating node: COURSE/MODULES/MOD');

        // LABELS

        $node_course_modules_mod_label = $labels->generate_node();

        // RESOURCES (WEB CONTENT AND WEB LINK)

        $node_course_modules_mod_resource = $resources->generate_node();

        // FORUMS

        $node_course_modules_mod_forum = $forums->generate_node();

        // QUIZ

        $node_course_modules_mod_quiz = $quiz->generate_node_course_modules_mod();

        //TODO: label

        $node_course_modules = $node_course_modules_mod_label . $node_course_modules_mod_resource . $node_course_modules_mod_forum . $node_course_modules_mod_quiz;

        return $node_course_modules;

    }

    protected function create_node_course_sections_section() {

        static::log_action('Creating node: COURSE/SECTIONS/SECTION');

        $node_course_sections_section = '';

        $sheet_course_sections_section = static::loadsheet(SHEET_COURSE_SECTIONS_SECTION);

        $topics = $this->get_nodes_by_criteria('deep', ROOT_DEEP);

        $i = 0;

        if (!empty($topics)) {

            foreach ($topics as $topic) {

                $i++;

                $node_node_course_sections_section_mods_mod = $this->create_node_course_sections_section_mods_mod($topic['index']);

                if ($topic['moodle_type'] == MOODLE_TYPE_LABEL) {

                    $find_tags = array('[#section_id#]',

                                       '[#section_number#]',

                                       '[#section_summary#]',

                                       '[#node_course_sections_section_mods_mod#]');

                    $replace_values = array($i,

                                            $i - 1,

                                            entities::safexml($topic['title']),

                                            $node_node_course_sections_section_mods_mod);

                } else {

                    $find_tags = array('[#section_id#]',

                                       '[#section_number#]',

                                       '[#section_summary#]',

                                       '[#node_course_sections_section_mods_mod#]');

                    $replace_values = array($i,

                                            $i - 1,

                                            '',

                                            $node_node_course_sections_section_mods_mod);

                }

                $node_course_sections_section .= str_replace($find_tags, $replace_values, $sheet_course_sections_section);

            }

        }

        return $node_course_sections_section;

    }

    protected function create_node_course_blocks_block() {

        global $CFG;

        static::log_action('Creating node: COURSE/BLOCKS/BLOCK');

        $sheet_course_blocks_block = static::loadsheet(SHEET_COURSE_BLOCKS_BLOCK);

        $node_course_blocks_block = '';

        $format_config = $CFG->dirroot . '/course/format/weeks/config.php';

        if (@is_file($format_config) && is_readable($format_config)) {

            require ($format_config);

        }

        if (!empty($format['defaultblocks'])) {

            $blocknames = $format['defaultblocks'];

        } else {

            if (isset($CFG->defaultblocks)) {

                $blocknames = $CFG->defaultblocks;

            } else {

                $blocknames = 'activity_modules,search_forums,course_list:news_items,calendar_upcoming,recent_activity';

            }

        }

        $blocknames = explode(':', $blocknames);

        $blocks_left = explode(',', $blocknames[0]);

        $blocks_right = explode(',', $blocknames[1]);

        $find_tags = array('[#block_id#]',

                           '[#block_name#]',

                           '[#block_position#]',

                           '[#block_weight#]');

        $i = 0;

        $weight = 0;

        foreach ($blocks_left as $block) {

            $i++;

            $weight++;

            $replace_values = array($i,

                                    $block,

                                    'l',

                                    $weight);

            $node_course_blocks_block .= str_replace($find_tags, $replace_values, $sheet_course_blocks_block);

        }

        $weight = 0;

        foreach ($blocks_right as $block) {

            $i++;

            $weight ++;

            $replace_values = array($i,

                                    $block,

                                    'r',

                                    $weight);

            $node_course_blocks_block .= str_replace($find_tags, $replace_values, $sheet_course_blocks_block);

        }

        return $node_course_blocks_block;

    }

    /**

    *

    * Is activity visible or not

    * @param string $identifier

    * @return number

    */

    protected function get_module_visible($identifier) {

        //Should item be hidden or not

        $mod_visible = 1;

        if (!empty($identifier)) {

            $xpath = static::newx_path(static::$manifest, static::$namespaces);

            $query  = '/imscc:manifest/imscc:resources/imscc:resource[@identifier="' . $identifier . '"]';

            $query .= '//lom:intendedEndUserRole/voc:vocabulary/lom:value';

            $intendeduserrole = $xpath->query($query);

            if (!empty($intendeduserrole) && ($intendeduserrole->length > 0)) {

                $role = trim($intendeduserrole->item(0)->nodeValue);

                if (strcasecmp('Instructor', $role) == 0) {

                    $mod_visible = 0;

                }

            }

        }

        return $mod_visible;

    }

    protected function create_node_course_sections_section_mods_mod($root_parent) {

        $sheet_course_sections_section_mods_mod = static::loadsheet(SHEET_COURSE_SECTIONS_SECTION_MODS_MOD);

        $childs = $this->get_nodes_by_criteria('root_parent', $root_parent);

        if ($childs) {

            $node_course_sections_section_mods_mod = '';

            foreach ($childs as $child) {

                if ($child['moodle_type'] == MOODLE_TYPE_LABEL) {

                    if ($child['index'] == $child['root_parent']) {

                        $is_summary = true;

                    } else {

                        $is_summary = false;

                    }

                } else {

                    $is_summary = false;

                }

                if (!$is_summary) {

                    $indent = $child['deep'] - ROOT_DEEP;

                    if ($indent > 0) {

                        $indent = $indent - 1;

                    }

                    $find_tags = array('[#mod_id#]',

                                       '[#mod_instance_id#]',

                                       '[#mod_type#]',

                                       '[#date_now#]',

                                       '[#mod_indent#]',

                                       '[#mod_visible#]');

                    $replace_values = array($child['index'],

                                            $child['instance'],

                                            $child['moodle_type'],

                                            time(),

                                            $indent,

                                            $this->get_module_visible($child['resource_indentifier']));

                    $node_course_sections_section_mods_mod .= str_replace($find_tags, $replace_values, $sheet_course_sections_section_mods_mod);

                }

            }

            $response = $node_course_sections_section_mods_mod;

        } else {

            $response = '';

        }

        return $response;

    }

    public function get_nodes_by_criteria($key, $value) {

        $response = array();

        if (array_key_exists('index', static::$instances)) {

            foreach (static::$instances['index'] as $item) {

                if ($item[$key] == $value) {

                    $response[] = $item;

                }

            }

        }

        return $response;

    }

    //Modified here

    protected function create_code_info_details_mod() {

        static::log_action('Creating node: INFO/DETAILS/MOD');

        $xpath = static::newx_path(static::$manifest, static::$namespaces);

        $items = $xpath->query('/imscc:manifest/imscc:organizations/imscc:organization/imscc:item | /imscc:manifest/imscc:resources/imscc:resource[@type="' . static::CC_TYPE_QUESTION_BANK . '"]');

        $this->create_instances($items);

        $count_quiz = $this->count_instances(MOODLE_TYPE_QUIZ);

        $count_forum = $this->count_instances(MOODLE_TYPE_FORUM);

        $count_resource = $this->count_instances(MOODLE_TYPE_RESOURCE);

        $count_label = $this->count_instances(MOODLE_TYPE_LABEL);

        $sheet_info_details_mod_instances_instance = static::loadsheet(SHEET_INFO_DETAILS_MOD_INSTANCE);

        if ($count_resource > 0) {

            $resource_instance = $this->create_mod_info_details_mod_instances_instance($sheet_info_details_mod_instances_instance, $count_resource, static::$instances['instances'][MOODLE_TYPE_RESOURCE]);

        }

        if ($count_quiz > 0) {

            $quiz_instance = $this->create_mod_info_details_mod_instances_instance($sheet_info_details_mod_instances_instance, $count_quiz, static::$instances['instances'][MOODLE_TYPE_QUIZ]);

        }

        if ($count_forum > 0) {

            $forum_instance = $this->create_mod_info_details_mod_instances_instance($sheet_info_details_mod_instances_instance, $count_forum, static::$instances['instances'][MOODLE_TYPE_FORUM]);

        }

        if ($count_label > 0) {

            $label_instance = $this->create_mod_info_details_mod_instances_instance($sheet_info_details_mod_instances_instance, $count_label, static::$instances['instances'][MOODLE_TYPE_LABEL]);

        }

        $resource_mod = $count_resource ? $this->create_mod_info_details_mod(MOODLE_TYPE_RESOURCE, $resource_instance) : '';

        $quiz_mod = $count_quiz ? $this->create_mod_info_details_mod(MOODLE_TYPE_QUIZ, $quiz_instance) : '';

        $forum_mod = $count_forum ? $this->create_mod_info_details_mod(MOODLE_TYPE_FORUM, $forum_instance) : '';

        $label_mod = $count_label ? $this->create_mod_info_details_mod(MOODLE_TYPE_LABEL, $label_instance) : '';

        //TODO: label

        return $label_mod . $resource_mod . $quiz_mod . $forum_mod;

    }

    protected function create_mod_info_details_mod($mod_type, $node_info_details_mod_instances_instance) {

        $sheet_info_details_mod = static::loadsheet(SHEET_INFO_DETAILS_MOD);

        $find_tags = array('[#mod_type#]' ,'[#node_info_details_mod_instances_instance#]');

        $replace_values = array($mod_type , $node_info_details_mod_instances_instance);

        return str_replace($find_tags, $replace_values, $sheet_info_details_mod);

    }

    protected function create_mod_info_details_mod_instances_instance($sheet, $instances_quantity, $instances) {

        $instance = '';

        $find_tags = array('[#mod_instance_id#]',

                           '[#mod_name#]',

                           '[#mod_user_info#]');

        for ($i = 1; $i <= $instances_quantity; $i++) {

            $user_info = ($instances[$i - 1]['common_cartriedge_type'] == static::CC_TYPE_FORUM) ? 'true' : 'false';

            if ($instances[$i - 1]['common_cartriedge_type'] == static::CC_TYPE_EMPTY) {

                if ($instances[$i - 1]['deep'] <= ROOT_DEEP ) {

                    continue;

                }

            }

            $replace_values = array($instances[$i - 1]['instance'],

                                    entities::safexml($instances[$i - 1]['title']),

                                    $user_info);

            $instance .= str_replace($find_tags, $replace_values, $sheet);

        }

        return $instance;

    }

    protected function create_instances($items, $level = 0, &$array_index = 0, $index_root = 0) {

        $level++;

        $i = 1;

        if ($items) {

            $xpath = self::newx_path(static::$manifest, static::$namespaces);

            foreach ($items as $item) {

                $array_index++;

                if ($item->nodeName == "item")  {

                    $identifierref = '';

                    if ($item->hasAttribute('identifierref')) {

                      $identifierref = $item->getAttribute('identifierref');

                    }

                    $title = '';

                    $titles = $xpath->query('imscc:title', $item);

                    if ($titles->length > 0) {

                        $title = $titles->item(0)->nodeValue;

                    }

                    $cc_type = $this->get_item_cc_type($identifierref);

                    $moodle_type = $this->convert_to_moodle_type($cc_type);

                    //Fix the label issue - MDL-33523

                    if (empty($identifierref) && empty($title)) {

                      $moodle_type = TYPE_UNKNOWN;

                    }

                }

                elseif ($item->nodeName == "resource")  {

                    $identifierref = $xpath->query('@identifier', $item);

                    $identifierref = !empty($identifierref->item(0)->nodeValue) ? $identifierref->item(0)->nodeValue : '';

                    $cc_type = $this->get_item_cc_type($identifierref);

                    $moodle_type = $this->convert_to_moodle_type($cc_type);

                    $title = 'Quiz Bank ' . ($this->count_instances($moodle_type) + 1);

                }

                if ($level == ROOT_DEEP) {

                    $index_root = $array_index;

                }

                static::$instances['index'][$array_index]['common_cartriedge_type'] = $cc_type;

                static::$instances['index'][$array_index]['moodle_type'] = $moodle_type;

                static::$instances['index'][$array_index]['title'] = $title ? $title : '';

                static::$instances['index'][$array_index]['root_parent'] = $index_root;

                static::$instances['index'][$array_index]['index'] = $array_index;

                static::$instances['index'][$array_index]['deep'] = $level;

                static::$instances['index'][$array_index]['instance'] = $this->count_instances($moodle_type);

                static::$instances['index'][$array_index]['resource_indentifier'] = $identifierref;

                static::$instances['instances'][$moodle_type][] = array('title' => $title,

                                                                        'instance' => static::$instances['index'][$array_index]['instance'],

                                                                        'common_cartriedge_type' => $cc_type,

                                                                        'resource_indentifier' => $identifierref,

                                                                        'deep' => $level);

                $more_items = $xpath->query('imscc:item', $item);

                if ($more_items->length > 0) {

                    $this->create_instances($more_items, $level, $array_index, $index_root);

                }

                $i++;

            }

        }

    }

    public function count_instances($type) {

        $quantity = 0;

        if (array_key_exists('index', static::$instances)) {

            if (static::$instances['index'] && $type) {

                foreach (static::$instances['index'] as $instance) {

                    if (!empty($instance['moodle_type'])) {

                        $types[] = $instance['moodle_type'];

                    }

                }

                $quantity_instances = array_count_values($types);

                $quantity = array_key_exists($type, $quantity_instances) ? $quantity_instances[$type] : 0;

            }

        }

        return $quantity;

    }

    public function convert_to_moodle_type($cc_type) {

        $type = TYPE_UNKNOWN;

        if ($cc_type == static::CC_TYPE_FORUM) {

            $type = MOODLE_TYPE_FORUM;

        }

        if ($cc_type == static::CC_TYPE_QUIZ) {

            $type = MOODLE_TYPE_QUIZ;

        }

        if ($cc_type == static::CC_TYPE_WEBLINK) {

            $type = MOODLE_TYPE_RESOURCE;

        }

        if ($cc_type == static::CC_TYPE_WEBCONTENT) {

            $type = MOODLE_TYPE_RESOURCE;

        }

        if ($cc_type == static::CC_TYPE_ASSOCIATED_CONTENT) {

            $type = MOODLE_TYPE_RESOURCE;

        }

        if ($cc_type == static::CC_TYPE_QUESTION_BANK) {

            $type = MOODLE_TYPE_QUESTION_BANK;

        }

        //TODO: label

        if ($cc_type == static::CC_TYPE_EMPTY) {

            $type = MOODLE_TYPE_LABEL;

        }

        return $type;

    }

    public function get_item_cc_type($identifier) {

        $xpath = static::newx_path(static::$manifest, static::$namespaces);

        $nodes = $xpath->query('/imscc:manifest/imscc:resources/imscc:resource[@identifier="' . $identifier . '"]/@type');

        if ($nodes && !empty($nodes->item(0)->nodeValue)) {

            return $nodes->item(0)->nodeValue;

        } else {

            return '';

        }

    }

    public static function newx_path(DOMDocument $manifest, $namespaces = '') {

        $xpath = new DOMXPath($manifest);

        if (!empty($namespaces)) {

            foreach ($namespaces as $prefix => $ns) {

                if (!$xpath->registerNamespace($prefix, $ns)) {

                    static::log_action('Cannot register the namespace: ' . $prefix . ':' . $ns, true);

                }

            }

        }

        return $xpath;

    }

    public static function loadsheet($file) {

        $content = (is_readable($file) && ($content = file_get_contents($file))) ? $content : false;

        static::log_action('Loading sheet: ' . $file);

        if (!$content) {

            static::log_action('Cannot load the xml sheet: ' . $file, true);

        }

        static::log_action('Load OK!');

        return $content;

    }

    public static function log_file() {

        return static::$path_to_manifest_folder . DIRECTORY_SEPARATOR . 'cc2moodle.log';

    }

    public static function log_action($text, $critical_error = false) {

        $full_message = strtoupper(date("j/n/Y g:i:s a")) . " - " . $text . "\r";

        file_put_contents(static::log_file(), $full_message, FILE_APPEND);

        if ($critical_error) {

            static::critical_error($text);

        }

    }

    protected static function critical_error($text) {

        $path_to_log = static::log_file();

        echo '

        <p>

        <hr />A critical error has been found!

        <p>' . $text . '</p>

        <p>

        The process has been stopped. Please see the <a href="' . $path_to_log . '">log file</a> for more information.</p>

        <p>Log: ' . $path_to_log . '</p>

        <hr />

        </p>

        ';

        die();

    }

    protected function create_course_code($title) {

        //Making sure that text of the short name does not go over the DB limit.

        //and leaving the space to add additional characters by the platform

        $code = substr(strtoupper(str_replace(' ', '', trim($title))),0,94);

        return $code;

    }

}