<?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 user API
 *
 * @package    moodlecore
 * @subpackage webservice
 * @copyright  2009 Moodle Pty Ltd (http://moodle.com)
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

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

class moodle_user_external extends external_api {

    /**
     * Returns description of method parameters
     * @return external_function_parameters
     */
    public static function create_users_parameters() {
        global $CFG;

        return new external_function_parameters(
            array(
                'users' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'username'    => new external_value(PARAM_USERNAME, 'Username policy is defined in Moodle security config. Must be lowercase.'),
                            'password'    => new external_value(PARAM_RAW, 'Plain text password consisting of any characters'),
                            'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user'),
                            'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user'),
                            'email'       => new external_value(PARAM_EMAIL, 'A valid and unique email address'),
                            'auth'        => new external_value(PARAM_SAFEDIR, 'Auth plugins include manual, ldap, imap, etc', VALUE_DEFAULT, 'manual', NULL_NOT_ALLOWED),
                            'idnumber'    => new external_value(PARAM_RAW, 'An arbitrary ID code number perhaps from the institution', VALUE_DEFAULT, ''),
                            'lang'        => new external_value(PARAM_SAFEDIR, 'Language code such as "en", must exist on server', VALUE_DEFAULT, $CFG->lang, NULL_NOT_ALLOWED),
                            'theme'       => new external_value(PARAM_SAFEDIR, 'Theme name such as "standard", must exist on server', VALUE_OPTIONAL),
                            'timezone'    => new external_value(PARAM_TIMEZONE, 'Timezone code such as Australia/Perth, or 99 for default', VALUE_OPTIONAL),
                            'mailformat'  => new external_value(PARAM_INTEGER, 'Mail format code is 0 for plain text, 1 for HTML etc', VALUE_OPTIONAL),
                            'description' => new external_value(PARAM_TEXT, 'User profile description, no HTML', VALUE_OPTIONAL),
                            'city'        => new external_value(PARAM_NOTAGS, 'Home city of the user', VALUE_OPTIONAL),
                            'country'     => new external_value(PARAM_ALPHA, 'Home country code of the user, such as AU or CZ', VALUE_OPTIONAL),
                            'preferences' => new external_multiple_structure(
                                new external_single_structure(
                                    array(
                                        'type'  => new external_value(PARAM_ALPHANUMEXT, 'The name of the preference'),
                                        'value' => new external_value(PARAM_RAW, 'The value of the preference')
                                    )
                                ), 'User preferences', VALUE_OPTIONAL),
                            'customfields' => new external_multiple_structure(
                                new external_single_structure(
                                    array(
                                        'type'  => new external_value(PARAM_ALPHANUMEXT, 'The name of the custom field'),
                                        'value' => new external_value(PARAM_RAW, 'The value of the custom field')
                                    )
                                ), 'User custom fields (also known as user profil fields)', VALUE_OPTIONAL)
                        )
                    )
                )
            )
        );
    }

    /**
     * Create one or more users
     *
     * @param array $users  An array of users to create.
     * @return array An array of arrays
     */
    public static function create_users($users) {
        global $CFG, $DB;
        require_once($CFG->dirroot."/lib/weblib.php");
        require_once($CFG->dirroot."/user/lib.php");
        require_once($CFG->dirroot."/user/profile/lib.php"); //required for customfields related function
                                                             //TODO: move the functions somewhere else as
                                                             //they are "user" related

        // Ensure the current user is allowed to run this function
        $context = get_context_instance(CONTEXT_SYSTEM);
        self::validate_context($context);
        require_capability('moodle/user:create', $context);

        // Do basic automatic PARAM checks on incoming data, using params description
        // If any problems are found then exceptions are thrown with helpful error messages
        $params = self::validate_parameters(self::create_users_parameters(), array('users'=>$users));

        $availableauths  = get_plugin_list('auth');
        unset($availableauths['mnet']);       // these would need mnethostid too
        unset($availableauths['webservice']); // we do not want new webservice users for now

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

        $transaction = $DB->start_delegated_transaction();

        $userids = array();
        foreach ($params['users'] as $user) {
            // Make sure that the username doesn't already exist
            if ($DB->record_exists('user', array('username'=>$user['username'], 'mnethostid'=>$CFG->mnet_localhost_id))) {
                throw new invalid_parameter_exception('Username already exists: '.$user['username']);
            }

            // Make sure auth is valid
            if (empty($availableauths[$user['auth']])) {
                throw new invalid_parameter_exception('Invalid authentication type: '.$user['auth']);
            }

            // Make sure lang is valid
            if (empty($availablelangs[$user['lang']])) {
                throw new invalid_parameter_exception('Invalid language code: '.$user['lang']);
            }

            // Make sure lang is valid
            if (!empty($user['theme']) && empty($availablethemes[$user['theme']])) { //theme is VALUE_OPTIONAL,
                                                                                     // so no default value.
                                                                                     // We need to test if the client sent it
                                                                                     // => !empty($user['theme'])
                throw new invalid_parameter_exception('Invalid theme: '.$user['theme']);
            }

            $user['confirmed'] = true;
            $user['mnethostid'] = $CFG->mnet_localhost_id;

            // Start of user info validation.
            // Lets make sure we validate current user info as handled by current GUI. see user/editadvanced_form.php function validation()
            if (!validate_email($user['email'])) {
                throw new invalid_parameter_exception('Email address is invalid: '.$user['email']);
            } else if ($DB->record_exists('user', array('email'=>$user['email'], 'mnethostid'=>$user['mnethostid']))) {
                throw new invalid_parameter_exception('Email address already exists: '.$user['email']);
            }
            // End of user info validation.

            // create the user data now!
            $user['id'] = user_create_user($user);

            // custom fields
            if(!empty($user['customfields'])) {
                foreach($user['customfields'] as $customfield) {
                    $user["profile_field_".$customfield['type']] = $customfield['value']; //profile_save_data() saves profile file
                                                                                            //it's expecting a user with the correct id,
                                                                                            //and custom field to be named profile_field_"shortname"
                }
                profile_save_data((object) $user);
            }

            //preferences
            if (!empty($user['preferences'])) {
                foreach($user['preferences'] as $preference) {
                    set_user_preference($preference['type'], $preference['value'],$user['id']);
                }
            }

            $userids[] = array('id'=>$user['id'], 'username'=>$user['username']);
        }

        $transaction->allow_commit();

        return $userids;
    }

   /**
     * Returns description of method result value
     * @return external_description
     */
    public static function create_users_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id'       => new external_value(PARAM_INT, 'user id'),
                    'username' => new external_value(PARAM_USERNAME, 'user name'),
                )
            )
        );
    }


    /**
     * Returns description of method parameters
     * @return external_function_parameters
     */
    public static function delete_users_parameters() {
        return new external_function_parameters(
            array(
                'userids' => new external_multiple_structure(new external_value(PARAM_INT, 'user ID')),
            )
        );
    }

    public static function delete_users($userids) {
        global $CFG, $DB, $USER;
        require_once($CFG->dirroot."/user/lib.php");

        // Ensure the current user is allowed to run this function
        $context = get_context_instance(CONTEXT_SYSTEM);
        require_capability('moodle/user:delete', $context);
        self::validate_context($context);

        $params = self::validate_parameters(self::delete_users_parameters(), array('userids'=>$userids));

        $transaction = $DB->start_delegated_transaction();

        foreach ($params['userids'] as $userid) {
            $user = $DB->get_record('user', array('id'=>$userid, 'deleted'=>0), '*', MUST_EXIST);
            // must not allow deleting of admins or self!!!
            if (is_siteadmin($user)) {
                throw new moodle_exception('useradminodelete', 'error');
            }
            if ($USER->id == $user->id) {
                throw new moodle_exception('usernotdeletederror', 'error');
            }
            user_delete_user($user);
        }

        $transaction->allow_commit();

        return null;
    }

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


    /**
     * Returns description of method parameters
     * @return external_function_parameters
     */
    public static function update_users_parameters() {
        global $CFG;
       return new external_function_parameters(
            array(
                'users' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'id'    => new external_value(PARAM_NUMBER, 'ID of the user'),
                            'username'    => new external_value(PARAM_USERNAME, 'Username policy is defined in Moodle security config. Must be lowercase.', VALUE_OPTIONAL, '',NULL_NOT_ALLOWED),
                            'password'    => new external_value(PARAM_RAW, 'Plain text password consisting of any characters', VALUE_OPTIONAL, '',NULL_NOT_ALLOWED),
                            'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user', VALUE_OPTIONAL, '',NULL_NOT_ALLOWED),
                            'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user', VALUE_OPTIONAL),
                            'email'       => new external_value(PARAM_EMAIL, 'A valid and unique email address', VALUE_OPTIONAL, '',NULL_NOT_ALLOWED),
                            'auth'        => new external_value(PARAM_SAFEDIR, 'Auth plugins include manual, ldap, imap, etc', VALUE_OPTIONAL, '', NULL_NOT_ALLOWED),
                            'idnumber'    => new external_value(PARAM_RAW, 'An arbitrary ID code number perhaps from the institution', VALUE_OPTIONAL),
                            'lang'        => new external_value(PARAM_SAFEDIR, 'Language code such as "en", must exist on server', VALUE_OPTIONAL, '', NULL_NOT_ALLOWED),
                            'theme'       => new external_value(PARAM_SAFEDIR, 'Theme name such as "standard", must exist on server', VALUE_OPTIONAL),
                            'timezone'    => new external_value(PARAM_TIMEZONE, 'Timezone code such as Australia/Perth, or 99 for default', VALUE_OPTIONAL),
                            'mailformat'  => new external_value(PARAM_INTEGER, 'Mail format code is 0 for plain text, 1 for HTML etc', VALUE_OPTIONAL),
                            'description' => new external_value(PARAM_TEXT, 'User profile description, no HTML', VALUE_OPTIONAL),
                            'city'        => new external_value(PARAM_NOTAGS, 'Home city of the user', VALUE_OPTIONAL),
                            'country'     => new external_value(PARAM_ALPHA, 'Home country code of the user, such as AU or CZ', VALUE_OPTIONAL),
                            'customfields' => new external_multiple_structure(
                                new external_single_structure(
                                    array(
                                        'type'  => new external_value(PARAM_ALPHANUMEXT, 'The name of the custom field'),
                                        'value' => new external_value(PARAM_RAW, 'The value of the custom field')
                                    )
                                ), 'User custom fields (also known as user profil fields)', VALUE_OPTIONAL),
                            'preferences' => new external_multiple_structure(
                                new external_single_structure(
                                    array(
                                        'type'  => new external_value(PARAM_ALPHANUMEXT, 'The name of the preference'),
                                        'value' => new external_value(PARAM_RAW, 'The value of the preference')
                                    )
                                ), 'User preferences', VALUE_OPTIONAL),
                        )
                    )
                )
            )
        );
    }

    public static function update_users($users) {
        global $CFG, $DB;
        require_once($CFG->dirroot."/user/lib.php");
        require_once($CFG->dirroot."/user/profile/lib.php"); //required for customfields related function
                                                             //TODO: move the functions somewhere else as
                                                             //they are "user" related

        // Ensure the current user is allowed to run this function
        $context = get_context_instance(CONTEXT_SYSTEM);
        require_capability('moodle/user:update', $context);
        self::validate_context($context);

        $params = self::validate_parameters(self::update_users_parameters(), array('users'=>$users));

        $transaction = $DB->start_delegated_transaction();

        foreach ($params['users'] as $user) {
            user_update_user($user);
            //update user custom fields
            if(!empty($user['customfields'])) {

                foreach($user['customfields'] as $customfield) {
                    $user["profile_field_".$customfield['type']] = $customfield['value']; //profile_save_data() saves profile file
                                                                                            //it's expecting a user with the correct id,
                                                                                            //and custom field to be named profile_field_"shortname"
                }
                profile_save_data((object) $user);
            }

            //preferences
            if (!empty($user['preferences'])) {
                foreach($user['preferences'] as $preference) {
                    set_user_preference($preference['type'], $preference['value'],$user['id']);
                }
            }
        }

        $transaction->allow_commit();

        return null;
    }

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

    /**
     * Returns description of method parameters
     * @return external_function_parameters
     */
    public static function get_users_by_id_parameters() {
        return new external_function_parameters(
                array(
                    'userids' => new external_multiple_structure(new external_value(PARAM_INT, 'user ID')),
                )
        );
    }

    /**
     * Get user information
     * - This function is matching the permissions of /user/profil.php
     * - It is also matching some permissions from /user/editadvanced.php for the following fields:
     *   auth, confirmed, idnumber, lang, theme, timezone, mailformat
     * @param array $userids  array of user ids
     * @return array An array of arrays describing users
     */
    public static function get_users_by_id($userids) {
        global $CFG, $USER, $DB;
        require_once($CFG->dirroot . "/user/lib.php");

        $params = self::validate_parameters(self::get_users_by_id_parameters(),
                array('userids'=>$userids));

        list($uselect, $ujoin) = context_instance_preload_sql('u.id', CONTEXT_USER, 'ctx');
        list($sqluserids, $params) = $DB->get_in_or_equal($userids);
        $usersql = "SELECT u.* $uselect
                      FROM {user} u $ujoin
                     WHERE u.id $sqluserids";
        $users = $DB->get_recordset_sql($usersql, $params);

        $result = array();
        $hasuserupdatecap = has_capability('moodle/user:update', get_system_context());
        foreach ($users as $user) {
            if (!empty($user->deleted)) {
                continue;
            }
            context_instance_preload($user);
            $usercontext = get_context_instance(CONTEXT_USER, $user->id);
            self::validate_context($usercontext);
            $currentuser = ($user->id == $USER->id);

            if ($userarray  = user_get_user_details($user)) {
                //fields matching permissions from /user/editadvanced.php
                if ($currentuser or $hasuserupdatecap) {
                    $userarray['auth']       = $user->auth;
                    $userarray['confirmed']  = $user->confirmed;
                    $userarray['idnumber']   = $user->idnumber;
                    $userarray['lang']       = $user->lang;
                    $userarray['theme']      = $user->theme;
                    $userarray['timezone']   = $user->timezone;
                    $userarray['mailformat'] = $user->mailformat;
                }
                $result[] = $userarray;
            }
        }
        $users->close();

        return $result;
    }

    /**
     * Returns description of method result value
     * @return external_description
     */
    public static function get_users_by_id_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id'    => new external_value(PARAM_NUMBER, 'ID of the user'),
                    'username'    => new external_value(PARAM_RAW, 'Username policy is defined in Moodle security config', VALUE_OPTIONAL),
                    'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user', VALUE_OPTIONAL),
                    'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user', VALUE_OPTIONAL),
                    'fullname'    => new external_value(PARAM_NOTAGS, 'The fullname of the user'),
                    'email'       => new external_value(PARAM_TEXT, 'An email address - allow email as root@localhost', VALUE_OPTIONAL),
                    'address'     => new external_value(PARAM_MULTILANG, 'Postal address', VALUE_OPTIONAL),
                    'phone1'      => new external_value(PARAM_NOTAGS, 'Phone 1', VALUE_OPTIONAL),
                    'phone2'      => new external_value(PARAM_NOTAGS, 'Phone 2', VALUE_OPTIONAL),
                    'icq'         => new external_value(PARAM_NOTAGS, 'icq number', VALUE_OPTIONAL),
                    'skype'       => new external_value(PARAM_NOTAGS, 'skype id', VALUE_OPTIONAL),
                    'yahoo'       => new external_value(PARAM_NOTAGS, 'yahoo id', VALUE_OPTIONAL),
                    'aim'         => new external_value(PARAM_NOTAGS, 'aim id', VALUE_OPTIONAL),
                    'msn'         => new external_value(PARAM_NOTAGS, 'msn number', VALUE_OPTIONAL),
                    'department'  => new external_value(PARAM_TEXT, 'department', VALUE_OPTIONAL),
                    'institution' => new external_value(PARAM_TEXT, 'institution', VALUE_OPTIONAL),
                    'interests'   => new external_value(PARAM_TEXT, 'user interests (separated by commas)', VALUE_OPTIONAL),
                    'firstaccess' => new external_value(PARAM_INT, 'first access to the site (0 if never)', VALUE_OPTIONAL),
                    'lastaccess'  => new external_value(PARAM_INT, 'last access to the site (0 if never)', VALUE_OPTIONAL),
                    'auth'        => new external_value(PARAM_SAFEDIR, 'Auth plugins include manual, ldap, imap, etc', VALUE_OPTIONAL),
                    'confirmed'   => new external_value(PARAM_NUMBER, 'Active user: 1 if confirmed, 0 otherwise', VALUE_OPTIONAL),
                    'idnumber'    => new external_value(PARAM_RAW, 'An arbitrary ID code number perhaps from the institution', VALUE_OPTIONAL),
                    'lang'        => new external_value(PARAM_SAFEDIR, 'Language code such as "en", must exist on server', VALUE_OPTIONAL),
                    'theme'       => new external_value(PARAM_SAFEDIR, 'Theme name such as "standard", must exist on server', VALUE_OPTIONAL),
                    'timezone'    => new external_value(PARAM_TIMEZONE, 'Timezone code such as Australia/Perth, or 99 for default', VALUE_OPTIONAL),
                    'mailformat'  => new external_value(PARAM_INTEGER, 'Mail format code is 0 for plain text, 1 for HTML etc', VALUE_OPTIONAL),
                    'description' => new external_value(PARAM_RAW, 'User profile description', VALUE_OPTIONAL),
                    'descriptionformat' => new external_value(PARAM_INT, 'User profile description format', VALUE_OPTIONAL),
                    'city'        => new external_value(PARAM_NOTAGS, 'Home city of the user', VALUE_OPTIONAL),
                    'url'         => new external_value(PARAM_URL, 'URL of the user', VALUE_OPTIONAL),
                    'country'     => new external_value(PARAM_ALPHA, 'Home country code of the user, such as AU or CZ', VALUE_OPTIONAL),
                    'profileimageurlsmall' => new external_value(PARAM_URL, 'User image profile URL - small version'),
                    'profileimageurl' => new external_value(PARAM_URL, 'User image profile URL - big version'),
                    'customfields' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'type'  => new external_value(PARAM_ALPHANUMEXT, 'The type of the custom field - text field, checkbox...'),
                                'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
                                'name' => new external_value(PARAM_RAW, 'The name of the custom field'),
                                'shortname' => new external_value(PARAM_RAW, 'The shortname of the custom field - to be able to build the field class in the code'),
                            )
                    ), 'User custom fields (also known as user profil fields)', VALUE_OPTIONAL),
                    'preferences' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'name'  => new external_value(PARAM_ALPHANUMEXT, 'The name of the preferences'),
                                'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
                            )
                    ), 'User preferences', VALUE_OPTIONAL),
                    'enrolledcourses' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'id'  => new external_value(PARAM_INT, 'Id of the course'),
                                'fullname'  => new external_value(PARAM_RAW, 'Fullname of the course'),
                                'shortname' => new external_value(PARAM_RAW, 'Shortname of the course')
                            )
                    ), 'Courses where the user is enrolled - limited by which courses the user is able to see', VALUE_OPTIONAL)
                )
            )
        );
    }
    /**
     * Returns description of method parameters
     * @return external_function_parameters
     */
    public static function get_course_participants_by_id_parameters() {
        return new external_function_parameters(
            array(
                'userlist' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'userid'    => new external_value(PARAM_INT, 'userid'),
                            'courseid'    => new external_value(PARAM_INT, 'courseid'),
                        )
                    )
                )
            )
        );
    }

    /**
     * Get course participant's details
     * @param array $userlist  array of user ids and according course ids
     * @return array An array of arrays describing course participants
     */
    public static function get_course_participants_by_id($userlist) {
        global $CFG, $USER, $DB;
        require_once($CFG->dirroot . "/user/lib.php");
        $params = self::validate_parameters(self::get_course_participants_by_id_parameters(), array('userlist'=>$userlist));

        $userids = array();
        $courseids = array();
        foreach ($params['userlist'] as $value) {
            $userids[] = $value['userid'];
            $courseids[$value['userid']] = $value['courseid'];
        }

        // cache all courses
        $courses = array();
        list($cselect, $cjoin) = context_instance_preload_sql('c.id', CONTEXT_COURSE, 'ctx');
        list($sqlcourseids, $params) = $DB->get_in_or_equal(array_unique($courseids));
        $coursesql = "SELECT c.* $cselect
                        FROM {course} c $cjoin
                       WHERE c.id $sqlcourseids";
        $rs = $DB->get_recordset_sql($coursesql, $params);
        foreach ($rs as $course) {
            // adding course contexts to cache
            context_instance_preload($course);
            // cache courses
            $courses[$course->id] = $course;
        }
        $rs->close();

        list($uselect, $ujoin) = context_instance_preload_sql('u.id', CONTEXT_USER, 'ctx');
        list($sqluserids, $params) = $DB->get_in_or_equal($userids);
        $usersql = "SELECT u.* $uselect
                      FROM {user} u $ujoin
                     WHERE u.id $sqluserids";
        $users = $DB->get_recordset_sql($usersql, $params);
        $result = array();
        foreach ($users as $user) {
            if (!empty($user->deleted)) {
                continue;
            }
            context_instance_preload($user);
            $course = $courses[$courseids[$user->id]];
            $context = get_context_instance(CONTEXT_COURSE, $courseids[$user->id]);
            self::validate_context($context);
            if ($userarray = user_get_user_details($user, $course)) {
                $result[] = $userarray;
            }
        }

        $users->close();

        return $result;
    }

    /**
     * Returns description of method result value
     * @return external_description
     */
    public static function get_course_participants_by_id_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id'    => new external_value(PARAM_NUMBER, 'ID of the user'),
                    'username'    => new external_value(PARAM_RAW, 'Username policy is defined in Moodle security config', VALUE_OPTIONAL),
                    'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user', VALUE_OPTIONAL),
                    'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user', VALUE_OPTIONAL),
                    'fullname'    => new external_value(PARAM_NOTAGS, 'The fullname of the user'),
                    'email'       => new external_value(PARAM_TEXT, 'An email address - allow email as root@localhost', VALUE_OPTIONAL),
                    'address'     => new external_value(PARAM_MULTILANG, 'Postal address', VALUE_OPTIONAL),
                    'phone1'      => new external_value(PARAM_NOTAGS, 'Phone 1', VALUE_OPTIONAL),
                    'phone2'      => new external_value(PARAM_NOTAGS, 'Phone 2', VALUE_OPTIONAL),
                    'icq'         => new external_value(PARAM_NOTAGS, 'icq number', VALUE_OPTIONAL),
                    'skype'       => new external_value(PARAM_NOTAGS, 'skype id', VALUE_OPTIONAL),
                    'yahoo'       => new external_value(PARAM_NOTAGS, 'yahoo id', VALUE_OPTIONAL),
                    'aim'         => new external_value(PARAM_NOTAGS, 'aim id', VALUE_OPTIONAL),
                    'msn'         => new external_value(PARAM_NOTAGS, 'msn number', VALUE_OPTIONAL),
                    'department'  => new external_value(PARAM_TEXT, 'department', VALUE_OPTIONAL),
                    'institution' => new external_value(PARAM_TEXT, 'institution', VALUE_OPTIONAL),
                    'interests'   => new external_value(PARAM_TEXT, 'user interests (separated by commas)', VALUE_OPTIONAL),
                    'firstaccess' => new external_value(PARAM_INT, 'first access to the site (0 if never)', VALUE_OPTIONAL),
                    'lastaccess'  => new external_value(PARAM_INT, 'last access to the site (0 if never)', VALUE_OPTIONAL),
                    'description' => new external_value(PARAM_RAW, 'User profile description', VALUE_OPTIONAL),
                    'descriptionformat' => new external_value(PARAM_INT, 'User profile description format', VALUE_OPTIONAL),
                    'city'        => new external_value(PARAM_NOTAGS, 'Home city of the user', VALUE_OPTIONAL),
                    'url'         => new external_value(PARAM_URL, 'URL of the user', VALUE_OPTIONAL),
                    'country'     => new external_value(PARAM_ALPHA, 'Home country code of the user, such as AU or CZ', VALUE_OPTIONAL),
                    'profileimageurlsmall' => new external_value(PARAM_URL, 'User image profile URL - small version'),
                    'profileimageurl' => new external_value(PARAM_URL, 'User image profile URL - big version'),
                    'customfields' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'type'  => new external_value(PARAM_ALPHANUMEXT, 'The type of the custom field - text field, checkbox...'),
                                'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
                                'name' => new external_value(PARAM_RAW, 'The name of the custom field'),
                                'shortname' => new external_value(PARAM_RAW, 'The shortname of the custom field - to be able to build the field class in the code'),
                            )
                        ), 'User custom fields (also known as user profil fields)', VALUE_OPTIONAL),
                    'groups' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'id'  => new external_value(PARAM_INT, 'group id'),
                                'name' => new external_value(PARAM_RAW, 'group name'),
                                'description' => new external_value(PARAM_RAW, 'group description'),
                            )
                        ), 'user groups', VALUE_OPTIONAL),
                    'roles' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'roleid'       => new external_value(PARAM_INT, 'role id'),
                                'name'         => new external_value(PARAM_RAW, 'role name'),
                                'shortname'    => new external_value(PARAM_ALPHANUMEXT, 'role shortname'),
                                'sortorder'    => new external_value(PARAM_INT, 'role sortorder')
                            )
                        ), 'user roles', VALUE_OPTIONAL),
                    'preferences' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'name'  => new external_value(PARAM_ALPHANUMEXT, 'The name of the preferences'),
                                'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
                            )
                    ), 'User preferences', VALUE_OPTIONAL),
                    'enrolledcourses' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'id'  => new external_value(PARAM_INT, 'Id of the course'),
                                'fullname' => new external_value(PARAM_RAW, 'Fullname of the course'),
                                'shortname' => new external_value(PARAM_RAW, 'Shortname of the course')
                            )
                    ), 'Courses where the user is enrolled - limited by which courses the user is able to see', VALUE_OPTIONAL)
                )
            )
        );
    }

    /**
     * Returns description of method parameters
     * @return external_function_parameters
     */
    public static function get_users_by_courseid_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_ALPHANUMEXT, 'option name'),
                            'value' => new external_value(PARAM_RAW, 'option value')
                        )
                    ), 'method options'),
            )
        );
    }

    /**
     * Get course participants details
     * @param int $courseid  course id
     * @param array $options options {
     *          'name' => option name
     *          'value' => option value
     * }
     * @return array An array of users
     */
    public static function get_users_by_courseid($courseid, $options) {
        global $CFG, $USER, $DB;
        require_once($CFG->dirroot . "/user/lib.php");

        $params = self::validate_parameters(
            self::get_users_by_courseid_parameters(),
            array(
                'courseid'=>$courseid,
                'options'=>$options
            )
        );
        $withcapability = '';
        $groupid        = 0;
        $onlyactive     = false;
        foreach ($options as $option) {
            switch ($option['name']) {
            case 'withcapability':
                $withcapability = $option['value'];
                break;
            case 'groupid':
                $groupid = (int)$option['value'];
                break;
            case 'onlyactive':
                $onlyactive = !empty($option['value']);
                break;
            }
        }

        // to overwrite this parameter, you need role:review capability
        if ($withcapability) {
            require_capability('moodle/role:review', $coursecontext);
        }
        // need accessallgroups capability if you want to overwrite this option
        if (!empty($groupid) && groups_is_member($groupid)) {
            require_capability('moodle/site:accessallgroups', $context);
        }
        // to overwrite this option, you need course:enrolereview permission
        if ($onlyactive) {
            require_capability('moodle/course:enrolreview', $coursecontext);
        }

        list($coursectxselect, $coursectxjoin) = context_instance_preload_sql('c.id', CONTEXT_COURSE, 'ctx');
        $coursesql = "SELECT c.* $coursectxselect
                        FROM {course} c $coursectxjoin
                       WHERE c.id = $courseid";
        $course = $DB->get_record_sql($coursesql);
        context_instance_preload($course);
        $coursecontext = get_context_instance(CONTEXT_COURSE, $params['courseid']);
        if ($courseid == SITEID) {
            $context = get_system_context();
        } else {
            $context = $coursecontext;
        }
        try {
            self::validate_context($context);
        } catch (Exception $e) {
            $exceptionparam = new stdClass();
            $exceptionparam->message = $e->getMessage();
            $exceptionparam->courseid = $params['courseid'];
            throw new moodle_exception(get_string('errorcoursecontextnotvalid' , 'webservice', $exceptionparam));
        }

        list($enrolledsql, $enrolledparams) = get_enrolled_sql($coursecontext, $withcapability, $groupid, $onlyactive);
        list($ctxselect, $ctxjoin) = context_instance_preload_sql('u.id', CONTEXT_USER, 'ctx');
        $records = $DB->get_records_sql($enrolledsql, $enrolledparams);
        $sqlparams['courseid'] = $courseid;
        $sql = "SELECT u.* $ctxselect
                  FROM {user} u $ctxjoin
                 WHERE u.id IN ($enrolledsql)
                 ORDER BY u.id ASC";
        $enrolledusers = $DB->get_recordset_sql($sql, $enrolledparams);
        $users = array();
        foreach ($enrolledusers as $user) {
            if (!empty($user->deleted)) {
                continue;
            }
            context_instance_preload($user);
            if ($userdetails = user_get_user_details($user, $course)) {
                $users[] = $userdetails;
            }
        }
        $enrolledusers->close();

        return $users;
    }
    /**
     * Returns description of method result value
     * @return external_description
     */
    public static function get_users_by_courseid_returns() {
        return new external_multiple_structure(
            new external_single_structure(
                array(
                    'id'    => new external_value(PARAM_NUMBER, 'ID of the user'),
                    'username'    => new external_value(PARAM_RAW, 'Username policy is defined in Moodle security config', VALUE_OPTIONAL),
                    'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user', VALUE_OPTIONAL),
                    'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user', VALUE_OPTIONAL),
                    'fullname'    => new external_value(PARAM_NOTAGS, 'The fullname of the user'),
                    'email'       => new external_value(PARAM_TEXT, 'An email address - allow email as root@localhost', VALUE_OPTIONAL),
                    'address'     => new external_value(PARAM_MULTILANG, 'Postal address', VALUE_OPTIONAL),
                    'phone1'      => new external_value(PARAM_NOTAGS, 'Phone 1', VALUE_OPTIONAL),
                    'phone2'      => new external_value(PARAM_NOTAGS, 'Phone 2', VALUE_OPTIONAL),
                    'icq'         => new external_value(PARAM_NOTAGS, 'icq number', VALUE_OPTIONAL),
                    'skype'       => new external_value(PARAM_NOTAGS, 'skype id', VALUE_OPTIONAL),
                    'yahoo'       => new external_value(PARAM_NOTAGS, 'yahoo id', VALUE_OPTIONAL),
                    'aim'         => new external_value(PARAM_NOTAGS, 'aim id', VALUE_OPTIONAL),
                    'msn'         => new external_value(PARAM_NOTAGS, 'msn number', VALUE_OPTIONAL),
                    'department'  => new external_value(PARAM_TEXT, 'department', VALUE_OPTIONAL),
                    'institution' => new external_value(PARAM_TEXT, 'institution', VALUE_OPTIONAL),
                    'interests'   => new external_value(PARAM_TEXT, 'user interests (separated by commas)', VALUE_OPTIONAL),
                    'firstaccess' => new external_value(PARAM_INT, 'first access to the site (0 if never)', VALUE_OPTIONAL),
                    'lastaccess'  => new external_value(PARAM_INT, 'last access to the site (0 if never)', VALUE_OPTIONAL),
                    'description' => new external_value(PARAM_RAW, 'User profile description', VALUE_OPTIONAL),
                    'descriptionformat' => new external_value(PARAM_INT, 'User profile description format', VALUE_OPTIONAL),
                    'city'        => new external_value(PARAM_NOTAGS, 'Home city of the user', VALUE_OPTIONAL),
                    'url'         => new external_value(PARAM_URL, 'URL of the user', VALUE_OPTIONAL),
                    'country'     => new external_value(PARAM_ALPHA, 'Home country code of the user, such as AU or CZ', VALUE_OPTIONAL),
                    'profileimageurlsmall' => new external_value(PARAM_URL, 'User image profile URL - small version'),
                    'profileimageurl' => new external_value(PARAM_URL, 'User image profile URL - big version'),
                    'customfields' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'type'  => new external_value(PARAM_ALPHANUMEXT, 'The type of the custom field - text field, checkbox...'),
                                'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
                                'name' => new external_value(PARAM_RAW, 'The name of the custom field'),
                                'shortname' => new external_value(PARAM_RAW, 'The shortname of the custom field - to be able to build the field class in the code'),
                            )
                        ), 'User custom fields (also known as user profil fields)', VALUE_OPTIONAL),
                    'groups' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'id'  => new external_value(PARAM_INT, 'group id'),
                                'name' => new external_value(PARAM_RAW, 'group name'),
                                'description' => new external_value(PARAM_RAW, 'group description'),
                            )
                        ), 'user groups', VALUE_OPTIONAL),
                    'roles' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'roleid'       => new external_value(PARAM_INT, 'role id'),
                                'name'         => new external_value(PARAM_RAW, 'role name'),
                                'shortname'    => new external_value(PARAM_ALPHANUMEXT, 'role shortname'),
                                'sortorder'    => new external_value(PARAM_INT, 'role sortorder')
                            )
                        ), 'user roles', VALUE_OPTIONAL),
                    'preferences' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'name'  => new external_value(PARAM_ALPHANUMEXT, 'The name of the preferences'),
                                'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
                            )
                    ), 'User preferences', VALUE_OPTIONAL),
                    'enrolledcourses' => new external_multiple_structure(
                        new external_single_structure(
                            array(
                                'id'  => new external_value(PARAM_INT, 'Id of the course'),
                                'fullname' => new external_value(PARAM_RAW, 'Fullname of the course'),
                                'shortname' => new external_value(PARAM_RAW, 'Shortname of the course')
                            )
                    ), 'Courses where the user is enrolled - limited by which courses the user is able to see', VALUE_OPTIONAL)
                )
            )
        );
    }
}
