<?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/>.


/**
 * External course API
 *
 * @package    core_course
 * @category   external
 * @copyright  2009 Petr Skodak
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die;

require_once("$CFG->libdir/externallib.php");

/**
 * Course external functions
 *
 * @package    core_course
 * @category   external
 * @copyright  2011 Jerome Mouneyrac
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 * @since Moodle 2.2
 */
class core_course_external extends external_api {

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.2
     */
    public static function get_course_contents_parameters() {
        return new external_function_parameters(
                array('courseid' => new external_value(PARAM_INT, 'course id'),
                      'options' => new external_multiple_structure (
                              new external_single_structure(
                                    array('name' => new external_value(PARAM_ALPHANUM, 'option name'),
                                          'value' => new external_value(PARAM_RAW, 'the value of the option, this param is personaly validated in the external function.')
                              )
                      ), 'Options, not used yet, might be used in later version', VALUE_DEFAULT, array())
                )
        );
    }

    /**
     * Get course contents
     *
     * @param int $courseid course id
     * @param array $options These options are not used yet, might be used in later version
     * @return array
     * @since Moodle 2.2
     */
    public static function get_course_contents($courseid, $options) {
        global $CFG, $DB;
        require_once($CFG->dirroot . "/course/lib.php");

        //validate parameter
        $params = self::validate_parameters(self::get_course_contents_parameters(),
                        array('courseid' => $courseid, 'options' => $options));

        //retrieve the course
        $course = $DB->get_record('course', array('id' => $params['courseid']), '*', MUST_EXIST);

        //check course format exist
        if (!file_exists($CFG->dirroot . '/course/format/' . $course->format . '/lib.php')) {
            throw new moodle_exception('cannotgetcoursecontents', 'webservice', '', null, get_string('courseformatnotfound', 'error', '', $course->format));
        } else {
            require_once($CFG->dirroot . '/course/format/' . $course->format . '/lib.php');
        }

        // now security checks
        $context = get_context_instance(CONTEXT_COURSE, $course->id);
        try {
            self::validate_context($context);
        } catch (Exception $e) {
            $exceptionparam = new stdClass();
            $exceptionparam->message = $e->getMessage();
            $exceptionparam->courseid = $course->id;
            throw new moodle_exception('errorcoursecontextnotvalid', 'webservice', '', $exceptionparam);
        }

        $canupdatecourse = has_capability('moodle/course:update', $context);

        //create return value
        $coursecontents = array();

        if ($canupdatecourse or $course->visible
                or has_capability('moodle/course:viewhiddencourses', $context)) {

            //retrieve sections
            $modinfo = get_fast_modinfo($course);
            $sections = get_all_sections($course->id);

            //for each sections (first displayed to last displayed)
            foreach ($sections as $key => $section) {

                $showsection = (has_capability('moodle/course:viewhiddensections', $context) or $section->visible or !$course->hiddensections);
                if (!$showsection) {
                    continue;
                }

                // reset $sectioncontents
                $sectionvalues = array();
                $sectionvalues['id'] = $section->id;
                $sectionvalues['name'] = get_section_name($course, $section);
                $summary = file_rewrite_pluginfile_urls($section->summary, 'webservice/pluginfile.php', $context->id, 'course', 'section', $section->id);
                $sectionvalues['visible'] = $section->visible;
                $sectionvalues['summary'] = format_text($summary, $section->summaryformat);
                $sectioncontents = array();

                //for each module of the section
                foreach ($modinfo->sections[$section->section] as $cmid) { //matching /course/lib.php:print_section() logic
                    $cm = $modinfo->cms[$cmid];

                    // stop here if the module is not visible to the user
                    if (!$cm->uservisible) {
                        continue;
                    }

                    $module = array();

                    //common info (for people being able to see the module or availability dates)
                    $module['id'] = $cm->id;
                    $module['name'] = format_string($cm->name, true);
                    $module['modname'] = $cm->modname;
                    $module['modplural'] = $cm->modplural;
                    $module['modicon'] = $cm->get_icon_url()->out(false);
                    $module['indent'] = $cm->indent;

                    $modcontext = get_context_instance(CONTEXT_MODULE, $cm->id);

                    if (!empty($cm->showdescription)) {
                        $module['description'] = $cm->get_content();
                    }

                    //url of the module
                    $url = $cm->get_url();
                    if ($url) { //labels don't have url
                        $module['url'] = $cm->get_url()->out();
                    }

                    $canviewhidden = has_capability('moodle/course:viewhiddenactivities',
                                        get_context_instance(CONTEXT_MODULE, $cm->id));
                    //user that can view hidden module should know about the visibility
                    $module['visible'] = $cm->visible;

                    //availability date (also send to user who can see hidden module when the showavailabilyt is ON)
                    if ($canupdatecourse or ($CFG->enableavailability && $canviewhidden && $cm->showavailability)) {
                        $module['availablefrom'] = $cm->availablefrom;
                        $module['availableuntil'] = $cm->availableuntil;
                    }

                    $baseurl = 'webservice/pluginfile.php';

                    //call $modulename_export_contents
                    //(each module callback take care about checking the capabilities)
                    require_once($CFG->dirroot . '/mod/' . $cm->modname . '/lib.php');
                    $getcontentfunction = $cm->modname.'_export_contents';
                    if (function_exists($getcontentfunction)) {
                        if ($contents = $getcontentfunction($cm, $baseurl)) {
                            $module['contents'] = $contents;
                        }
                    }

                    //assign result to $sectioncontents
                    $sectioncontents[] = $module;

                }
                $sectionvalues['modules'] = $sectioncontents;

                // assign result to $coursecontents
                $coursecontents[] = $sectionvalues;
            }
        }
        return $coursecontents;
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.2
     */
    public static function get_course_contents_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id' => new external_value(PARAM_INT, 'Section ID'),
                    'name' => new external_value(PARAM_TEXT, 'Section name'),
                    'visible' => new external_value(PARAM_INT, 'is the section visible', VALUE_OPTIONAL),
                    'summary' => new external_value(PARAM_RAW, 'Section description'),
                    'modules' => new external_multiple_structure(
                            new external_single_structure(
                                array(
                                    'id' => new external_value(PARAM_INT, 'activity id'),
                                    'url' => new external_value(PARAM_URL, 'activity url', VALUE_OPTIONAL),
                                    'name' => new external_value(PARAM_TEXT, 'activity module name'),
                                    'description' => new external_value(PARAM_RAW, 'activity description', VALUE_OPTIONAL),
                                    'visible' => new external_value(PARAM_INT, 'is the module visible', VALUE_OPTIONAL),
                                    'modicon' => new external_value(PARAM_URL, 'activity icon url'),
                                    'modname' => new external_value(PARAM_PLUGIN, 'activity module type'),
                                    'modplural' => new external_value(PARAM_TEXT, 'activity module plural name'),
                                    'availablefrom' => new external_value(PARAM_INT, 'module availability start date', VALUE_OPTIONAL),
                                    'availableuntil' => new external_value(PARAM_INT, 'module availability en date', VALUE_OPTIONAL),
                                    'indent' => new external_value(PARAM_INT, 'number of identation in the site'),
                                    'contents' => new external_multiple_structure(
                                          new external_single_structure(
                                              array(
                                                  // content info
                                                  'type'=> new external_value(PARAM_TEXT, 'a file or a folder or external link'),
                                                  'filename'=> new external_value(PARAM_FILE, 'filename'),
                                                  'filepath'=> new external_value(PARAM_PATH, 'filepath'),
                                                  'filesize'=> new external_value(PARAM_INT, 'filesize'),
                                                  'fileurl' => new external_value(PARAM_URL, 'downloadable file url', VALUE_OPTIONAL),
                                                  'content' => new external_value(PARAM_RAW, 'Raw content, will be used when type is content', VALUE_OPTIONAL),
                                                  'timecreated' => new external_value(PARAM_INT, 'Time created'),
                                                  'timemodified' => new external_value(PARAM_INT, 'Time modified'),
                                                  'sortorder' => new external_value(PARAM_INT, 'Content sort order'),

                                                  // copyright related info
                                                  'userid' => new external_value(PARAM_INT, 'User who added this content to moodle'),
                                                  'author' => new external_value(PARAM_TEXT, 'Content owner'),
                                                  'license' => new external_value(PARAM_TEXT, 'Content license'),
                                              )
                                          ), VALUE_DEFAULT, array()
                                      )
                                )
                            ), 'list of module'
                    )
                )
            )
        );
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function get_courses_parameters() {
        return new external_function_parameters(
                array('options' => new external_single_structure(
                            array('ids' => new external_multiple_structure(
                                        new external_value(PARAM_INT, 'Course id')
                                        , 'List of course id. If empty return all courses
                                            except front page course.',
                                        VALUE_OPTIONAL)
                            ), 'options - operator OR is used', VALUE_DEFAULT, array())
                )
        );
    }

    /**
     * Get courses
     *
     * @param array $options It contains an array (list of ids)
     * @return array
     * @since Moodle 2.2
     */
    public static function get_courses($options) {
        global $CFG, $DB;
        require_once($CFG->dirroot . "/course/lib.php");

        //validate parameter
        $params = self::validate_parameters(self::get_courses_parameters(),
                        array('options' => $options));

        //retrieve courses
        if (!key_exists('ids', $params['options'])
                or empty($params['options']['ids'])) {
            $courses = $DB->get_records('course');
        } else {
            $courses = $DB->get_records_list('course', 'id', $params['options']['ids']);
        }

        //create return value
        $coursesinfo = array();
        foreach ($courses as $course) {

            // now security checks
            $context = get_context_instance(CONTEXT_COURSE, $course->id);
            try {
                self::validate_context($context);
            } catch (Exception $e) {
                $exceptionparam = new stdClass();
                $exceptionparam->message = $e->getMessage();
                $exceptionparam->courseid = $course->id;
                throw new moodle_exception(
                        get_string('errorcoursecontextnotvalid', 'webservice', $exceptionparam));
            }
            require_capability('moodle/course:view', $context);

            $courseinfo = array();
            $courseinfo['id'] = $course->id;
            $courseinfo['fullname'] = $course->fullname;
            $courseinfo['shortname'] = $course->shortname;
            $courseinfo['categoryid'] = $course->category;
            $courseinfo['summary'] = $course->summary;
            $courseinfo['summaryformat'] = $course->summaryformat;
            $courseinfo['format'] = $course->format;
            $courseinfo['startdate'] = $course->startdate;
            $courseinfo['numsections'] = $course->numsections;

            //some field should be returned only if the user has update permission
            $courseadmin = has_capability('moodle/course:update', $context);
            if ($courseadmin) {
                $courseinfo['categorysortorder'] = $course->sortorder;
                $courseinfo['idnumber'] = $course->idnumber;
                $courseinfo['showgrades'] = $course->showgrades;
                $courseinfo['showreports'] = $course->showreports;
                $courseinfo['newsitems'] = $course->newsitems;
                $courseinfo['visible'] = $course->visible;
                $courseinfo['maxbytes'] = $course->maxbytes;
                $courseinfo['hiddensections'] = $course->hiddensections;
                $courseinfo['groupmode'] = $course->groupmode;
                $courseinfo['groupmodeforce'] = $course->groupmodeforce;
                $courseinfo['defaultgroupingid'] = $course->defaultgroupingid;
                $courseinfo['lang'] = $course->lang;
                $courseinfo['timecreated'] = $course->timecreated;
                $courseinfo['timemodified'] = $course->timemodified;
                $courseinfo['forcetheme'] = $course->theme;
                $courseinfo['enablecompletion'] = $course->enablecompletion;
                $courseinfo['completionstartonenrol'] = $course->completionstartonenrol;
                $courseinfo['completionnotify'] = $course->completionnotify;
            }

            if ($courseadmin or $course->visible
                    or has_capability('moodle/course:viewhiddencourses', $context)) {
                $coursesinfo[] = $courseinfo;
            }
        }

        return $coursesinfo;
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.2
     */
    public static function get_courses_returns() {
        return new external_multiple_structure(
                new external_single_structure(
                        array(
                            'id' => new external_value(PARAM_INT, 'course id'),
                            'shortname' => new external_value(PARAM_TEXT, 'course short name'),
                            'categoryid' => new external_value(PARAM_INT, 'category id'),
                            'categorysortorder' => new external_value(PARAM_INT,
                                    'sort order into the category', VALUE_OPTIONAL),
                            'fullname' => new external_value(PARAM_TEXT, 'full name'),
                            'idnumber' => new external_value(PARAM_RAW, 'id number', VALUE_OPTIONAL),
                            'summary' => new external_value(PARAM_RAW, 'summary'),
                            'summaryformat' => new external_value(PARAM_INT,
                                    'the summary text Moodle format'),
                            'format' => new external_value(PARAM_PLUGIN,
                                    'course format: weeks, topics, social, site,..'),
                            'showgrades' => new external_value(PARAM_INT,
                                    '1 if grades are shown, otherwise 0', VALUE_OPTIONAL),
                            'newsitems' => new external_value(PARAM_INT,
                                    'number of recent items appearing on the course page', VALUE_OPTIONAL),
                            'startdate' => new external_value(PARAM_INT,
                                    'timestamp when the course start'),
                            'numsections' => new external_value(PARAM_INT, 'number of weeks/topics'),
                            'maxbytes' => new external_value(PARAM_INT,
                                    'largest size of file that can be uploaded into the course',
                                    VALUE_OPTIONAL),
                            'showreports' => new external_value(PARAM_INT,
                                    'are activity report shown (yes = 1, no =0)', VALUE_OPTIONAL),
                            'visible' => new external_value(PARAM_INT,
                                    '1: available to student, 0:not available', VALUE_OPTIONAL),
                            'hiddensections' => new external_value(PARAM_INT,
                                    'How the hidden sections in the course are displayed to students',
                                    VALUE_OPTIONAL),
                            'groupmode' => new external_value(PARAM_INT, 'no group, separate, visible',
                                    VALUE_OPTIONAL),
                            'groupmodeforce' => new external_value(PARAM_INT, '1: yes, 0: no',
                                    VALUE_OPTIONAL),
                            'defaultgroupingid' => new external_value(PARAM_INT, 'default grouping id',
                                    VALUE_OPTIONAL),
                            'timecreated' => new external_value(PARAM_INT,
                                    'timestamp when the course have been created', VALUE_OPTIONAL),
                            'timemodified' => new external_value(PARAM_INT,
                                    'timestamp when the course have been modified', VALUE_OPTIONAL),
                            'enablecompletion' => new external_value(PARAM_INT,
                                    'Enabled, control via completion and activity settings. Disbaled,
                                        not shown in activity settings.',
                                    VALUE_OPTIONAL),
                            'completionstartonenrol' => new external_value(PARAM_INT,
                                    '1: begin tracking a student\'s progress in course completion
                                        after course enrolment. 0: does not',
                                    VALUE_OPTIONAL),
                            'completionnotify' => new external_value(PARAM_INT,
                                    '1: yes 0: no', VALUE_OPTIONAL),
                            'lang' => new external_value(PARAM_SAFEDIR,
                                    'forced course language', VALUE_OPTIONAL),
                            'forcetheme' => new external_value(PARAM_PLUGIN,
                                    'name of the force theme', VALUE_OPTIONAL),
                        ), 'course'
                )
        );
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.2
     */
    public static function create_courses_parameters() {
        $courseconfig = get_config('moodlecourse'); //needed for many default values
        return new external_function_parameters(
            array(
                'courses' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'fullname' => new external_value(PARAM_TEXT, 'full name'),
                            'shortname' => new external_value(PARAM_TEXT, 'course short name'),
                            'categoryid' => new external_value(PARAM_INT, 'category id'),
                            'idnumber' => new external_value(PARAM_RAW, 'id number', VALUE_OPTIONAL),
                            'summary' => new external_value(PARAM_RAW, 'summary', VALUE_OPTIONAL),
                            'summaryformat' => new external_value(PARAM_INT,
                                    'the summary text Moodle format', VALUE_DEFAULT, FORMAT_MOODLE),
                            'format' => new external_value(PARAM_PLUGIN,
                                    'course format: weeks, topics, social, site,..',
                                    VALUE_DEFAULT, $courseconfig->format),
                            'showgrades' => new external_value(PARAM_INT,
                                    '1 if grades are shown, otherwise 0', VALUE_DEFAULT,
                                    $courseconfig->showgrades),
                            'newsitems' => new external_value(PARAM_INT,
                                    'number of recent items appearing on the course page',
                                    VALUE_DEFAULT, $courseconfig->newsitems),
                            'startdate' => new external_value(PARAM_INT,
                                    'timestamp when the course start', VALUE_OPTIONAL),
                            'numsections' => new external_value(PARAM_INT, 'number of weeks/topics',
                                    VALUE_DEFAULT, $courseconfig->numsections),
                            'maxbytes' => new external_value(PARAM_INT,
                                    'largest size of file that can be uploaded into the course',
                                    VALUE_DEFAULT, $courseconfig->maxbytes),
                            'showreports' => new external_value(PARAM_INT,
                                    'are activity report shown (yes = 1, no =0)', VALUE_DEFAULT,
                                    $courseconfig->showreports),
                            'visible' => new external_value(PARAM_INT,
                                    '1: available to student, 0:not available', VALUE_OPTIONAL),
                            'hiddensections' => new external_value(PARAM_INT,
                                    'How the hidden sections in the course are displayed to students',
                                    VALUE_DEFAULT, $courseconfig->hiddensections),
                            'groupmode' => new external_value(PARAM_INT, 'no group, separate, visible',
                                    VALUE_DEFAULT, $courseconfig->groupmode),
                            'groupmodeforce' => new external_value(PARAM_INT, '1: yes, 0: no',
                                    VALUE_DEFAULT, $courseconfig->groupmodeforce),
                            'defaultgroupingid' => new external_value(PARAM_INT, 'default grouping id',
                                    VALUE_DEFAULT, 0),
                            'enablecompletion' => new external_value(PARAM_INT,
                                    'Enabled, control via completion and activity settings. Disabled,
                                        not shown in activity settings.',
                                    VALUE_OPTIONAL),
                            'completionstartonenrol' => new external_value(PARAM_INT,
                                    '1: begin tracking a student\'s progress in course completion after
                                        course enrolment. 0: does not',
                                    VALUE_OPTIONAL),
                            'completionnotify' => new external_value(PARAM_INT,
                                    '1: yes 0: no', VALUE_OPTIONAL),
                            'lang' => new external_value(PARAM_SAFEDIR,
                                    'forced course language', VALUE_OPTIONAL),
                            'forcetheme' => new external_value(PARAM_PLUGIN,
                                    'name of the force theme', VALUE_OPTIONAL),
                        )
                    ), 'courses to create'
                )
            )
        );
    }

    /**
     * Create  courses
     *
     * @param array $courses
     * @return array courses (id and shortname only)
     * @since Moodle 2.2
     */
    public static function create_courses($courses) {
        global $CFG, $DB;
        require_once($CFG->dirroot . "/course/lib.php");
        require_once($CFG->libdir . '/completionlib.php');

        $params = self::validate_parameters(self::create_courses_parameters(),
                        array('courses' => $courses));

        $availablethemes = get_plugin_list('theme');
        $availablelangs = get_string_manager()->get_list_of_translations();

        $transaction = $DB->start_delegated_transaction();

        foreach ($params['courses'] as $course) {

            // Ensure the current user is allowed to run this function
            $context = get_context_instance(CONTEXT_COURSECAT, $course['categoryid']);
            try {
                self::validate_context($context);
            } catch (Exception $e) {
                $exceptionparam = new stdClass();
                $exceptionparam->message = $e->getMessage();
                $exceptionparam->catid = $course['categoryid'];
                throw new moodle_exception(
                        get_string('errorcatcontextnotvalid', 'webservice', $exceptionparam));
            }
            require_capability('moodle/course:create', $context);

            // Make sure lang is valid
            if (key_exists('lang', $course) and empty($availablelangs[$course['lang']])) {
                throw new moodle_exception(
                        get_string('errorinvalidparam', 'webservice', 'lang'));
            }

            // Make sure theme is valid
            if (key_exists('forcetheme', $course)) {
                if (!empty($CFG->allowcoursethemes)) {
                    if (empty($availablethemes[$course['forcetheme']])) {
                        throw new moodle_exception(
                                get_string('errorinvalidparam', 'webservice', 'forcetheme'));
                    } else {
                        $course['theme'] = $course['forcetheme'];
                    }
                }
            }

            //force visibility if ws user doesn't have the permission to set it
            $category = $DB->get_record('course_categories', array('id' => $course['categoryid']));
            if (!has_capability('moodle/course:visibility', $context)) {
                $course['visible'] = $category->visible;
            }

            //set default value for completion
            $courseconfig = get_config('moodlecourse');
            if (completion_info::is_enabled_for_site()) {
                if (!key_exists('enablecompletion', $course)) {
                    $course['enablecompletion'] = $courseconfig->enablecompletion;
                }
                if (!key_exists('completionstartonenrol', $course)) {
                    $course['completionstartonenrol'] = $courseconfig->completionstartonenrol;
                }
            } else {
                $course['enablecompletion'] = 0;
                $course['completionstartonenrol'] = 0;
            }

            $course['category'] = $course['categoryid'];

            //Note: create_course() core function check shortname, idnumber, category
            $course['id'] = create_course((object) $course)->id;

            $resultcourses[] = array('id' => $course['id'], 'shortname' => $course['shortname']);
        }

        $transaction->allow_commit();

        return $resultcourses;
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.2
     */
    public static function create_courses_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id'       => new external_value(PARAM_INT, 'course id'),
                    'shortname' => new external_value(PARAM_TEXT, 'short name'),
                )
            )
        );
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.2
     */
    public static function delete_courses_parameters() {
        return new external_function_parameters(
            array(
                'courseids' => new external_multiple_structure(new external_value(PARAM_INT, 'course ID')),
            )
        );
    }

    /**
     * Delete courses
     *
     * @param array $courseids A list of course ids
     * @since Moodle 2.2
     */
    public static function delete_courses($courseids) {
        global $CFG, $DB;
        require_once($CFG->dirroot."/course/lib.php");

        // Parameter validation.
        $params = self::validate_parameters(self::delete_courses_parameters(), array('courseids'=>$courseids));

        $transaction = $DB->start_delegated_transaction();

        foreach ($params['courseids'] as $courseid) {
            $course = $DB->get_record('course', array('id'=>$courseid), '*', MUST_EXIST);

            // Check if the context is valid.
            $coursecontext = context_course::instance($course->id);
            self::validate_context($coursecontext);

            // Check if the current user has enought permissions.
            if (!can_delete_course($courseid)) {
                throw new moodle_exception('cannotdeletecategorycourse', 'error',
                    '', format_string($course->fullname)." (id: $courseid)");
            }

            delete_course($course, false);
        }

        $transaction->allow_commit();

        return null;
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.2
     */
    public static function delete_courses_returns() {
        return null;
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function duplicate_course_parameters() {
        return new external_function_parameters(
            array(
                'courseid' => new external_value(PARAM_INT, 'course to duplicate id'),
                'fullname' => new external_value(PARAM_TEXT, 'duplicated course full name'),
                'shortname' => new external_value(PARAM_TEXT, 'duplicated course short name'),
                'categoryid' => new external_value(PARAM_INT, 'duplicated course category parent'),
                'visible' => new external_value(PARAM_INT, 'duplicated course visible, default to yes', VALUE_DEFAULT, 1),
                'options' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                                'name' => new external_value(PARAM_ALPHA, 'The backup option name:
                                            "activities" (int) Include course activites (default to 1 that is equal to yes),
                                            "blocks" (int) Include course blocks (default to 1 that is equal to yes),
                                            "filters" (int) Include course filters  (default to 1 that is equal to yes),
                                            "users" (int) Include users (default to 0 that is equal to no),
                                            "role_assignments" (int) Include role assignments  (default to 0 that is equal to no),
                                            "user_files" (int) Include user files  (default to 0 that is equal to no),
                                            "comments" (int) Include user comments  (default to 0 that is equal to no),
                                            "completion_information" (int) Include user course completion information  (default to 0 that is equal to no),
                                            "logs" (int) Include course logs  (default to 0 that is equal to no),
                                            "histories" (int) Include histories  (default to 0 that is equal to no)'
                                            ),
                                'value' => new external_value(PARAM_RAW, 'the value for the option 1 (yes) or 0 (no)'
                            )
                        )
                    ), VALUE_DEFAULT, array()
                ),
            )
        );
    }

    /**
     * Duplicate a course
     *
     * @param int $courseid
     * @param string $fullname Duplicated course fullname
     * @param string $shortname Duplicated course shortname
     * @param int $categoryid Duplicated course parent category id
     * @param int $visible Duplicated course availability
     * @param array $options List of backup options
     * @return array New course info
     * @since Moodle 2.3
     */
    public static function duplicate_course($courseid, $fullname, $shortname, $categoryid, $visible, $options) {
        global $CFG, $USER, $DB;
        require_once($CFG->dirroot . '/backup/util/includes/backup_includes.php');
        require_once($CFG->dirroot . '/backup/util/includes/restore_includes.php');

        // Parameter validation.
        $params = self::validate_parameters(
                self::duplicate_course_parameters(),
                array(
                      'courseid' => $courseid,
                      'fullname' => $fullname,
                      'shortname' => $shortname,
                      'categoryid' => $categoryid,
                      'visible' => $visible,
                      'options' => $options
                )
        );

        // Context validation.

        if (! ($course = $DB->get_record('course', array('id'=>$params['courseid'])))) {
            throw new moodle_exception('invalidcourseid', 'error', '', $params['courseid']);
        }

        // Category where duplicated course is going to be created.
        $categorycontext = context_coursecat::instance($params['categoryid']);
        self::validate_context($categorycontext);

        // Course to be duplicated.
        $coursecontext = context_course::instance($course->id);
        self::validate_context($coursecontext);

        $backupdefaults = array(
            'activities' => 1,
            'blocks' => 1,
            'filters' => 1,
            'users' => 0,
            'role_assignments' => 0,
            'user_files' => 0,
            'comments' => 0,
            'completion_information' => 0,
            'logs' => 0,
            'histories' => 0
        );

        $backupsettings = array();
        // Check for backup and restore options.
        if (!empty($params['options'])) {
            foreach ($params['options'] as $option) {

                // Strict check for a correct value (allways 1 or 0, true or false).
                $value = clean_param($option['value'], PARAM_INT);

                if ($value !== 0 and $value !== 1) {
                    throw new moodle_exception('invalidextparam', 'webservice', '', $option['name']);
                }

                if (!isset($backupdefaults[$option['name']])) {
                    throw new moodle_exception('invalidextparam', 'webservice', '', $option['name']);
                }

                $backupsettings[$option['name']] = $value;
            }
        }

        // Capability checking.

        // The backup controller check for this currently, this may be redundant.
        require_capability('moodle/course:create', $categorycontext);
        require_capability('moodle/restore:restorecourse', $categorycontext);
        require_capability('moodle/backup:backupcourse', $coursecontext);

        if (!empty($backupsettings['users'])) {
            require_capability('moodle/backup:userinfo', $coursecontext);
            require_capability('moodle/restore:userinfo', $categorycontext);
        }

        // Check if the shortname is used.
        if ($foundcourses = $DB->get_records('course', array('shortname'=>$shortname))) {
            foreach ($foundcourses as $foundcourse) {
                $foundcoursenames[] = $foundcourse->fullname;
            }

            $foundcoursenamestring = implode(',', $foundcoursenames);
            throw new moodle_exception('shortnametaken', '', '', $foundcoursenamestring);
        }

        // Backup the course.

        $bc = new backup_controller(backup::TYPE_1COURSE, $course->id, backup::FORMAT_MOODLE,
        backup::INTERACTIVE_NO, backup::MODE_SAMESITE, $USER->id);

        foreach ($backupsettings as $name => $value) {
            $bc->get_plan()->get_setting($name)->set_value($value);
        }

        $backupid       = $bc->get_backupid();
        $backupbasepath = $bc->get_plan()->get_basepath();

        $bc->execute_plan();
        $results = $bc->get_results();
        $file = $results['backup_destination'];

        $bc->destroy();

        // Restore the backup immediately.

        // Check if we need to unzip the file because the backup temp dir does not contains backup files.
        if (!file_exists($backupbasepath . "/moodle_backup.xml")) {
            $file->extract_to_pathname(get_file_packer(), $backupbasepath);
        }

        // Create new course.
        $newcourseid = restore_dbops::create_new_course($params['fullname'], $params['shortname'], $params['categoryid']);

        $rc = new restore_controller($backupid, $newcourseid,
                backup::INTERACTIVE_NO, backup::MODE_SAMESITE, $USER->id, backup::TARGET_NEW_COURSE);

        foreach ($backupsettings as $name => $value) {
            $setting = $rc->get_plan()->get_setting($name);
            if ($setting->get_status() == backup_setting::NOT_LOCKED) {
                $setting->set_value($value);
            }
        }

        if (!$rc->execute_precheck()) {
            $precheckresults = $rc->get_precheck_results();
            if (is_array($precheckresults) && !empty($precheckresults['errors'])) {
                if (empty($CFG->keeptempdirectoriesonbackup)) {
                    fulldelete($backupbasepath);
                }

                $errorinfo = '';

                foreach ($precheckresults['errors'] as $error) {
                    $errorinfo .= $error;
                }

                if (array_key_exists('warnings', $precheckresults)) {
                    foreach ($precheckresults['warnings'] as $warning) {
                        $errorinfo .= $warning;
                    }
                }

                throw new moodle_exception('backupprecheckerrors', 'webservice', '', $errorinfo);
            }
        }

        $rc->execute_plan();
        $rc->destroy();

        $course = $DB->get_record('course', array('id' => $newcourseid), '*', MUST_EXIST);
        $course->fullname = $params['fullname'];
        $course->shortname = $params['shortname'];
        $course->visible = $params['visible'];

        // Set shortname and fullname back.
        $DB->update_record('course', $course);

        if (empty($CFG->keeptempdirectoriesonbackup)) {
            fulldelete($backupbasepath);
        }

        // Delete the course backup file created by this WebService. Originally located in the course backups area.
        $file->delete();

        return array('id' => $course->id, 'shortname' => $course->shortname);
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.3
     */
    public static function duplicate_course_returns() {
        return new external_single_structure(
            array(
                'id'       => new external_value(PARAM_INT, 'course id'),
                'shortname' => new external_value(PARAM_TEXT, 'short name'),
            )
        );
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function get_categories_parameters() {
        return new external_function_parameters(
            array(
                'criteria' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'key' => new external_value(PARAM_ALPHA,
                                         'The category column to search, expected keys (value format) are:'.
                                         '"id" (int) the category id,'.
                                         '"name" (string) the category name,'.
                                         '"parent" (int) the parent category id,'.
                                         '"idnumber" (string) category idnumber'.
                                         ' - user must have \'moodle/category:manage\' to search on idnumber,'.
                                         '"visible" (int) whether the category is visible or not'.
                                         ' - user must have \'moodle/category:manage\' or \'moodle/category:viewhiddencategories\' to search on visible,'.
                                         '"theme" (string) category theme'.
                                         ' - user must have \'moodle/category:manage\' to search on theme'),
                            'value' => new external_value(PARAM_RAW, 'the value to match')
                        )
                    ), VALUE_DEFAULT, array()
                ),
                'addsubcategories' => new external_value(PARAM_BOOL, 'return the sub categories infos
                                          (1 - default) otherwise only the category info (0)', VALUE_DEFAULT, 1)
            )
        );
    }

    /**
     * Get categories
     *
     * @param array $criteria Criteria to match the results
     * @param booln $addsubcategories obtain only the category (false) or its subcategories (true - default)
     * @return array list of categories
     * @since Moodle 2.3
     */
    public static function get_categories($criteria = array(), $addsubcategories = true) {
        global $CFG, $DB;
        require_once($CFG->dirroot . "/course/lib.php");

        // Validate parameters.
        $params = self::validate_parameters(self::get_categories_parameters(),
                array('criteria' => $criteria, 'addsubcategories' => $addsubcategories));

        // Retrieve the categories.
        $categories = array();
        if (!empty($params['criteria'])) {

            $conditions = array();
            $wheres = array();
            foreach ($params['criteria'] as $crit) {
                $key = trim($crit['key']);

                // Trying to avoid duplicate keys.
                if (!isset($conditions[$key])) {

                    $context = context_system::instance();
                    $value = null;
                    switch ($key) {
                        case 'id':
                            $value = clean_param($crit['value'], PARAM_INT);
                            break;

                        case 'idnumber':
                            if (has_capability('moodle/category:manage', $context)) {
                                $value = clean_param($crit['value'], PARAM_RAW);
                            } else {
                                // We must throw an exception.
                                // Otherwise the dev client would think no idnumber exists.
                                throw new moodle_exception('criteriaerror',
                                        'webservice', '', null,
                                        'You don\'t have the permissions to search on the "idnumber" field.');
                            }
                            break;

                        case 'name':
                            $value = clean_param($crit['value'], PARAM_TEXT);
                            break;

                        case 'parent':
                            $value = clean_param($crit['value'], PARAM_INT);
                            break;

                        case 'visible':
                            if (has_capability('moodle/category:manage', $context)
                                or has_capability('moodle/category:viewhiddencategories',
                                        context_system::instance())) {
                                $value = clean_param($crit['value'], PARAM_INT);
                            } else {
                                throw new moodle_exception('criteriaerror',
                                        'webservice', '', null,
                                        'You don\'t have the permissions to search on the "visible" field.');
                            }
                            break;

                        case 'theme':
                            if (has_capability('moodle/category:manage', $context)) {
                                $value = clean_param($crit['value'], PARAM_THEME);
                            } else {
                                throw new moodle_exception('criteriaerror',
                                        'webservice', '', null,
                                        'You don\'t have the permissions to search on the "theme" field.');
                            }
                            break;

                        default:
                            throw new moodle_exception('criteriaerror',
                                    'webservice', '', null,
                                    'You can not search on this criteria: ' . $key);
                    }

                    if (isset($value)) {
                        $conditions[$key] = $crit['value'];
                        $wheres[] = $key . " = :" . $key;
                    }
                }
            }

            if (!empty($wheres)) {
                $wheres = implode(" AND ", $wheres);

                $categories = $DB->get_records_select('course_categories', $wheres, $conditions);

                // Retrieve its sub subcategories (all levels).
                if ($categories and !empty($params['addsubcategories'])) {
                    $newcategories = array();

                    foreach ($categories as $category) {
                        $sqllike = $DB->sql_like('path', ':path');
                        $sqlparams = array('path' => $category->path.'/%'); // It will NOT include the specified category.
                        $subcategories = $DB->get_records_select('course_categories', $sqllike, $sqlparams);
                        $newcategories = $newcategories + $subcategories;   // Both arrays have integer as keys.
                    }
                    $categories = $categories + $newcategories;
                }
            }

        } else {
            // Retrieve all categories in the database.
            $categories = $DB->get_records('course_categories');
        }

        // The not returned categories. key => category id, value => reason of exclusion.
        $excludedcats = array();

        // The returned categories.
        $categoriesinfo = array();

        // We need to sort the categories by path.
        // The parent cats need to be checked by the algo first.
        usort($categories, "core_course_external::compare_categories_by_path");

        foreach ($categories as $category) {

            // Check if the category is a child of an excluded category, if yes exclude it too (excluded => do not return).
            $parents = explode('/', $category->path);
            unset($parents[0]); // First key is always empty because path start with / => /1/2/4.
            foreach ($parents as $parentid) {
                // Note: when the parent exclusion was due to the context,
                // the sub category could still be returned.
                if (isset($excludedcats[$parentid]) and $excludedcats[$parentid] != 'context') {
                    $excludedcats[$category->id] = 'parent';
                }
            }

            // Check category depth is <= maxdepth (do not check for user who can manage categories).
            if ((!empty($CFG->maxcategorydepth) && count($parents) > $CFG->maxcategorydepth)
                    and !has_capability('moodle/category:manage', $context)) {
                $excludedcats[$category->id] = 'depth';
            }

            // Check the user can use the category context.
            $context = context_coursecat::instance($category->id);
            try {
                self::validate_context($context);
            } catch (Exception $e) {
                $excludedcats[$category->id] = 'context';

                // If it was the requested category then throw an exception.
                if (isset($params['categoryid']) && $category->id == $params['categoryid']) {
                    $exceptionparam = new stdClass();
                    $exceptionparam->message = $e->getMessage();
                    $exceptionparam->catid = $category->id;
                    throw new moodle_exception('errorcatcontextnotvalid', 'webservice', '', $exceptionparam);
                }
            }

            // Return the category information.
            if (!isset($excludedcats[$category->id])) {

                // Final check to see if the category is visible to the user.
                if ($category->visible
                        or has_capability('moodle/category:viewhiddencategories', context_system::instance())
                        or has_capability('moodle/category:manage', $context)) {

                    $categoryinfo = array();
                    $categoryinfo['id'] = $category->id;
                    $categoryinfo['name'] = $category->name;
                    $categoryinfo['description'] = file_rewrite_pluginfile_urls($category->description,
                            'webservice/pluginfile.php', $context->id, 'coursecat', 'description', null);
                    $options = new stdClass;
                    $options->noclean = true;
                    $options->para = false;
                    $categoryinfo['description'] = format_text($categoryinfo['description'],
                            $category->descriptionformat, $options);
                    $categoryinfo['parent'] = $category->parent;
                    $categoryinfo['sortorder'] = $category->sortorder;
                    $categoryinfo['coursecount'] = $category->coursecount;
                    $categoryinfo['depth'] = $category->depth;
                    $categoryinfo['path'] = $category->path;

                    // Some fields only returned for admin.
                    if (has_capability('moodle/category:manage', $context)) {
                        $categoryinfo['idnumber'] = $category->idnumber;
                        $categoryinfo['visible'] = $category->visible;
                        $categoryinfo['visibleold'] = $category->visibleold;
                        $categoryinfo['timemodified'] = $category->timemodified;
                        $categoryinfo['theme'] = $category->theme;
                    }

                    $categoriesinfo[] = $categoryinfo;
                } else {
                    $excludedcats[$category->id] = 'visibility';
                }
            }
        }

        // Sorting the resulting array so it looks a bit better for the client developer.
        usort($categoriesinfo, "core_course_external::compare_categories_by_sortorder");

        return $categoriesinfo;
    }

    /**
     * Sort categories array by path
     * private function: only used by get_categories
     *
     * @param array $category1
     * @param array $category2
     * @return int result of strcmp
     * @since Moodle 2.3
     */
    private static function compare_categories_by_path($category1, $category2) {
        return strcmp($category1->path, $category2->path);
    }

    /**
     * Sort categories array by sortorder
     * private function: only used by get_categories
     *
     * @param array $category1
     * @param array $category2
     * @return int result of strcmp
     * @since Moodle 2.3
     */
    private static function compare_categories_by_sortorder($category1, $category2) {
        return strcmp($category1['sortorder'], $category2['sortorder']);
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.3
     */
    public static function get_categories_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id' => new external_value(PARAM_INT, 'category id'),
                    'name' => new external_value(PARAM_TEXT, 'category name'),
                    'idnumber' => new external_value(PARAM_RAW, 'category id number', VALUE_OPTIONAL),
                    'description' => new external_value(PARAM_RAW, 'category description'),
                    'parent' => new external_value(PARAM_INT, 'parent category id'),
                    'sortorder' => new external_value(PARAM_INT, 'category sorting order'),
                    'coursecount' => new external_value(PARAM_INT, 'number of courses in this category'),
                    'visible' => new external_value(PARAM_INT, '1: available, 0:not available', VALUE_OPTIONAL),
                    'visibleold' => new external_value(PARAM_INT, '1: available, 0:not available', VALUE_OPTIONAL),
                    'timemodified' => new external_value(PARAM_INT, 'timestamp', VALUE_OPTIONAL),
                    'depth' => new external_value(PARAM_INT, 'category depth'),
                    'path' => new external_value(PARAM_TEXT, 'category path'),
                    'theme' => new external_value(PARAM_THEME, 'category theme', VALUE_OPTIONAL),
                ), 'List of categories'
            )
        );
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function create_categories_parameters() {
        return new external_function_parameters(
            array(
                'categories' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'name' => new external_value(PARAM_TEXT, 'new category name'),
                                'parent' => new external_value(PARAM_INT,
                                        'the parent category id inside which the new category will be created'),
                                'idnumber' => new external_value(PARAM_RAW,
                                        'the new category idnumber', VALUE_OPTIONAL),
                                'description' => new external_value(PARAM_RAW,
                                        'the new category description', VALUE_OPTIONAL),
                                'theme' => new external_value(PARAM_THEME,
                                        'the new category theme. This option must be enabled on moodle',
                                        VALUE_OPTIONAL),
                        )
                    )
                )
            )
        );
    }

    /**
     * Create categories
     *
     * @param array $categories - see create_categories_parameters() for the array structure
     * @return array - see create_categories_returns() for the array structure
     * @since Moodle 2.3
     */
    public static function create_categories($categories) {
        global $CFG, $DB;
        require_once($CFG->dirroot . "/course/lib.php");

        $params = self::validate_parameters(self::create_categories_parameters(),
                        array('categories' => $categories));

        $transaction = $DB->start_delegated_transaction();

        $createdcategories = array();
        foreach ($params['categories'] as $category) {
            if ($category['parent']) {
                if (!$DB->record_exists('course_categories', array('id' => $category['parent']))) {
                    throw new moodle_exception('unknowcategory');
                }
                $context = context_coursecat::instance($category['parent']);
            } else {
                $context = context_system::instance();
            }
            self::validate_context($context);
            require_capability('moodle/category:manage', $context);

            // Check id number.
            if (!empty($category['idnumber'])) { // Same as in course/editcategory_form.php .
                if (textlib::strlen($category['idnumber'])>100) {
                    throw new moodle_exception('idnumbertoolong');
                }
                if ($existing = $DB->get_record('course_categories', array('idnumber' => $category['idnumber']))) {
                    if ($existing->id) {
                        throw new moodle_exception('idnumbertaken');
                    }
                }
            }
            // Check name.
            if (textlib::strlen($category['name'])>255) {
                throw new moodle_exception('categorytoolong');
            }

            $newcategory = new stdClass();
            $newcategory->name = $category['name'];
            $newcategory->parent = $category['parent'];
            $newcategory->idnumber = $category['idnumber'];
            $newcategory->sortorder = 999; // Same as in the course/editcategory.php .
            // Format the description.
            if (!empty($category['description'])) {
                $newcategory->description = $category['description'];
            }
            $newcategory->descriptionformat = FORMAT_HTML;
            if (isset($category['theme']) and !empty($CFG->allowcategorythemes)) {
                $newcategory->theme = $category['theme'];
            }

            $newcategory = create_course_category($newcategory);
            // Populate special fields.
            fix_course_sortorder();

            $createdcategories[] = array('id' => $newcategory->id, 'name' => $newcategory->name);
        }

        $transaction->allow_commit();

        return $createdcategories;
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function create_categories_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id' => new external_value(PARAM_INT, 'new category id'),
                    'name' => new external_value(PARAM_TEXT, 'new category name'),
                )
            )
        );
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function update_categories_parameters() {
        return new external_function_parameters(
            array(
                'categories' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'id'       => new external_value(PARAM_INT, 'course id'),
                            'name' => new external_value(PARAM_TEXT, 'category name', VALUE_OPTIONAL),
                            'idnumber' => new external_value(PARAM_RAW, 'category id number', VALUE_OPTIONAL),
                            'parent' => new external_value(PARAM_INT, 'parent category id', VALUE_OPTIONAL),
                            'description' => new external_value(PARAM_RAW, 'category description', VALUE_OPTIONAL),
                            'theme' => new external_value(PARAM_THEME,
                                    'the category theme. This option must be enabled on moodle', VALUE_OPTIONAL),
                        )
                    )
                )
            )
        );
    }

    /**
     * Update categories
     *
     * @param array $categories The list of categories to update
     * @return null
     * @since Moodle 2.3
     */
    public static function update_categories($categories) {
        global $CFG, $DB;
        require_once($CFG->dirroot . "/course/lib.php");

        // Validate parameters.
        $params = self::validate_parameters(self::update_categories_parameters(), array('categories' => $categories));

        $transaction = $DB->start_delegated_transaction();

        foreach ($params['categories'] as $cat) {
            if (!$category = $DB->get_record('course_categories', array('id' => $cat['id']))) {
                throw new moodle_exception('unknowcategory');
            }

            $categorycontext = context_coursecat::instance($cat['id']);
            self::validate_context($categorycontext);
            require_capability('moodle/category:manage', $categorycontext);

            if (!empty($cat['name'])) {
                if (textlib::strlen($cat['name'])>255) {
                     throw new moodle_exception('categorytoolong');
                }
                $category->name = $cat['name'];
            }
            if (!empty($cat['idnumber'])) {
                if (textlib::strlen($cat['idnumber'])>100) {
                    throw new moodle_exception('idnumbertoolong');
                }
                $category->idnumber = $cat['idnumber'];
            }
            if (!empty($cat['description'])) {
                $category->description = $cat['description'];
                $category->descriptionformat = FORMAT_HTML;
            }
            if (!empty($cat['theme'])) {
                $category->theme = $cat['theme'];
            }
            if (!empty($cat['parent']) && ($category->parent != $cat['parent'])) {
                // First check if parent exists.
                if (!$parent_cat = $DB->get_record('course_categories', array('id' => $cat['parent']))) {
                    throw new moodle_exception('unknowcategory');
                }
                // Then check if we have capability.
                self::validate_context(get_category_or_system_context((int)$cat['parent']));
                require_capability('moodle/category:manage', get_category_or_system_context((int)$cat['parent']));
                // Finally move the category.
                move_category($category, $parent_cat);
                $category->parent = $cat['parent'];
            }
            $DB->update_record('course_categories', $category);
        }

        $transaction->allow_commit();
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.3
     */
    public static function update_categories_returns() {
        return null;
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function delete_categories_parameters() {
        return new external_function_parameters(
            array(
                'categories' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'id' => new external_value(PARAM_INT, 'category id to delete'),
                            'newparent' => new external_value(PARAM_INT,
                                'the parent category to move the contents to, if specified', VALUE_OPTIONAL),
                            'recursive' => new external_value(PARAM_BOOL, '1: recursively delete all contents inside this
                                category, 0 (default): move contents to newparent or current parent category (except if parent is root)', VALUE_DEFAULT, 0)
                        )
                    )
                )
            )
        );
    }

    /**
     * Delete categories
     *
     * @param array $categories A list of category ids
     * @return array
     * @since Moodle 2.3
     */
    public static function delete_categories($categories) {
        global $CFG, $DB;
        require_once($CFG->dirroot . "/course/lib.php");

        // Validate parameters.
        $params = self::validate_parameters(self::delete_categories_parameters(), array('categories' => $categories));

        foreach ($params['categories'] as $category) {
            if (!$deletecat = $DB->get_record('course_categories', array('id' => $category['id']))) {
                throw new moodle_exception('unknowcategory');
            }
            $context = context_coursecat::instance($deletecat->id);
            require_capability('moodle/category:manage', $context);
            self::validate_context($context);
            self::validate_context(get_category_or_system_context($deletecat->parent));

            if ($category['recursive']) {
                // If recursive was specified, then we recursively delete the category's contents.
                category_delete_full($deletecat, false);
            } else {
                // In this situation, we don't delete the category's contents, we either move it to newparent or parent.
                // If the parent is the root, moving is not supported (because a course must always be inside a category).
                // We must move to an existing category.
                if (!empty($category['newparent'])) {
                    if (!$DB->record_exists('course_categories', array('id' => $category['newparent']))) {
                        throw new moodle_exception('unknowcategory');
                    }
                    $newparent = $category['newparent'];
                } else {
                    $newparent = $deletecat->parent;
                }

                // This operation is not allowed. We must move contents to an existing category.
                if ($newparent == 0) {
                    throw new moodle_exception('movecatcontentstoroot');
                }

                $parentcontext = get_category_or_system_context($newparent);
                require_capability('moodle/category:manage', $parentcontext);
                self::validate_context($parentcontext);
                category_delete_move($deletecat, $newparent, false);
            }
        }

    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.3
     */
    public static function delete_categories_returns() {
        return null;
    }

}

/**
 * Deprecated course external functions
 *
 * @package    core_course
 * @copyright  2009 Petr Skodak
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 * @since Moodle 2.0
 * @deprecated Moodle 2.2 MDL-29106 - Please do not use this class any more.
 * @todo MDL-31194 This will be deleted in Moodle 2.5.
 * @see core_course_external
 */
class moodle_course_external extends external_api {

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.0
     * @deprecated Moodle 2.2 MDL-29106 - Please do not call this function any more.
     * @todo MDL-31194 This will be deleted in Moodle 2.5.
     * @see core_course_external::get_courses_parameters()
     */
    public static function get_courses_parameters() {
        return core_course_external::get_courses_parameters();
    }

    /**
     * Get courses
     *
     * @param array $options
     * @return array
     * @since Moodle 2.0
     * @deprecated Moodle 2.2 MDL-29106 - Please do not call this function any more.
     * @todo MDL-31194 This will be deleted in Moodle 2.5.
     * @see core_course_external::get_courses()
     */
    public static function get_courses($options) {
        return core_course_external::get_courses($options);
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.0
     * @deprecated Moodle 2.2 MDL-29106 - Please do not call this function any more.
     * @todo MDL-31194 This will be deleted in Moodle 2.5.
     * @see core_course_external::get_courses_returns()
     */
    public static function get_courses_returns() {
        return core_course_external::get_courses_returns();
    }

    /**
     * Returns description of method parameters
     *
     * @return external_function_parameters
     * @since Moodle 2.0
     * @deprecated Moodle 2.2 MDL-29106 - Please do not call this function any more.
     * @todo MDL-31194 This will be deleted in Moodle 2.5.
     * @see core_course_external::create_courses_parameters()
     */
    public static function create_courses_parameters() {
        return core_course_external::create_courses_parameters();
    }

    /**
     * Create  courses
     *
     * @param array $courses
     * @return array courses (id and shortname only)
     * @since Moodle 2.0
     * @deprecated Moodle 2.2 MDL-29106 - Please do not call this function any more.
     * @todo MDL-31194 This will be deleted in Moodle 2.5.
     * @see core_course_external::create_courses()
     */
    public static function create_courses($courses) {
        return core_course_external::create_courses($courses);
    }

    /**
     * Returns description of method result value
     *
     * @return external_description
     * @since Moodle 2.0
     * @deprecated Moodle 2.2 MDL-29106 - Please do not call this function any more.
     * @todo MDL-31194 This will be deleted in Moodle 2.5.
     * @see core_course_external::create_courses_returns()
     */
    public static function create_courses_returns() {
        return core_course_external::create_courses_returns();
    }

}