C:/xampp/htdocs/moodle/lib/moodlelib.php

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<?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/>.

defined('MOODLE_INTERNAL') || die();



define('YEARSECS', 31536000);

define('WEEKSECS', 604800);

define('DAYSECS', 86400);

define('HOURSECS', 3600);

define('MINSECS', 60);

define('DAYMINS', 1440);

define('HOURMINS', 60);




define('PARAM_ALPHA',    'alpha');

define('PARAM_ALPHAEXT', 'alphaext');

define('PARAM_ALPHANUM', 'alphanum');

define('PARAM_ALPHANUMEXT', 'alphanumext');

define('PARAM_AUTH',  'auth');

define('PARAM_BASE64',   'base64');

define('PARAM_BOOL',     'bool');

define('PARAM_CAPABILITY',   'capability');

define('PARAM_CLEANHTML', 'cleanhtml');

define('PARAM_EMAIL',   'email');

define('PARAM_FILE',   'file');

define('PARAM_FLOAT',  'float');

define('PARAM_HOST',     'host');

define('PARAM_INT',      'int');

define('PARAM_LANG',  'lang');

define('PARAM_LOCALURL', 'localurl');

define('PARAM_NOTAGS',   'notags');

define('PARAM_PATH',     'path');

define('PARAM_PEM',      'pem');

define('PARAM_PERMISSION',   'permission');

define('PARAM_RAW', 'raw');

define('PARAM_RAW_TRIMMED', 'raw_trimmed');

define('PARAM_SAFEDIR',  'safedir');

define('PARAM_SAFEPATH',  'safepath');

define('PARAM_SEQUENCE',  'sequence');

define('PARAM_TAG',   'tag');

define('PARAM_TAGLIST',   'taglist');

define('PARAM_TEXT',  'text');

define('PARAM_THEME',  'theme');

define('PARAM_URL',      'url');

define('PARAM_USERNAME',    'username');

define('PARAM_STRINGID',    'stringid');


define('PARAM_CLEAN',    'clean');

define('PARAM_INTEGER',  'int');

define('PARAM_NUMBER',  'float');

define('PARAM_ACTION',   'alphanumext');

define('PARAM_FORMAT',   'alphanumext');

define('PARAM_MULTILANG',  'text');

define('PARAM_TIMEZONE', 'timezone');

define('PARAM_CLEANFILE', 'file');

define('PARAM_COMPONENT', 'component');

define('PARAM_AREA', 'area');

define('PARAM_PLUGIN', 'plugin');



define('VALUE_REQUIRED', 1);

define('VALUE_OPTIONAL', 2);

define('VALUE_DEFAULT', 0);

define('NULL_NOT_ALLOWED', false);

define('NULL_ALLOWED', true);


define('PAGE_COURSE_VIEW', 'course-view');

define('GETREMOTEADDR_SKIP_HTTP_CLIENT_IP', '1');
define('GETREMOTEADDR_SKIP_HTTP_X_FORWARDED_FOR', '2');

define ('BLOG_USER_LEVEL', 1);
define ('BLOG_GROUP_LEVEL', 2);
define ('BLOG_COURSE_LEVEL', 3);
define ('BLOG_SITE_LEVEL', 4);
define ('BLOG_GLOBAL_LEVEL', 5);



define('TAG_MAX_LENGTH', 50);

define ('PASSWORD_LOWER', 'abcdefghijklmnopqrstuvwxyz');
define ('PASSWORD_UPPER', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ');
define ('PASSWORD_DIGITS', '0123456789');
define ('PASSWORD_NONALPHANUM', '.,;:!?_-+/*@#&$');

// Used for plugin_supports() to report features that are, or are not, supported by a module.

define('FEATURE_GRADE_HAS_GRADE', 'grade_has_grade');
define('FEATURE_GRADE_OUTCOMES', 'outcomes');
define('FEATURE_ADVANCED_GRADING', 'grade_advanced_grading');

define('FEATURE_COMPLETION_TRACKS_VIEWS', 'completion_tracks_views');
define('FEATURE_COMPLETION_HAS_RULES', 'completion_has_rules');

define('FEATURE_NO_VIEW_LINK', 'viewlink');
define('FEATURE_IDNUMBER', 'idnumber');
define('FEATURE_GROUPS', 'groups');
define('FEATURE_GROUPINGS', 'groupings');
define('FEATURE_GROUPMEMBERSONLY', 'groupmembersonly');

define('FEATURE_MOD_ARCHETYPE', 'mod_archetype');
define('FEATURE_MOD_INTRO', 'mod_intro');
define('FEATURE_MODEDIT_DEFAULT_COMPLETION', 'modedit_default_completion');

define('FEATURE_COMMENT', 'comment');

define('FEATURE_RATE', 'rate');
define('FEATURE_BACKUP_MOODLE2', 'backup_moodle2');

define('FEATURE_SHOW_DESCRIPTION', 'showdescription');

define('MOD_ARCHETYPE_OTHER', 0);
define('MOD_ARCHETYPE_RESOURCE', 1);
define('MOD_ARCHETYPE_ASSIGNMENT', 2);

define('EXTERNAL_TOKEN_PERMANENT', 0);

define('EXTERNAL_TOKEN_EMBEDDED', 1);

define('HOMEPAGE_SITE', 0);
define('HOMEPAGE_MY', 1);
define('HOMEPAGE_USER', 2);

define('HUB_HUBDIRECTORYURL', "http://hubdirectory.moodle.org");


define('HUB_MOODLEORGHUBURL', "http://hub.moodle.org");

define('MOODLE_OFFICIAL_MOBILE_SERVICE', 'moodle_mobile_app');


function required_param($parname, $type) {
    if (func_num_args() != 2 or empty($parname) or empty($type)) {
        throw new coding_exception('required_param() requires $parname and $type to be specified (parameter: '.$parname.')');
    }
    if (isset($_POST[$parname])) {       // POST has precedence
        $param = $_POST[$parname];
    } else if (isset($_GET[$parname])) {
        $param = $_GET[$parname];
    } else {
        print_error('missingparam', '', '', $parname);
    }

    if (is_array($param)) {
        debugging('Invalid array parameter detected in required_param(): '.$parname);
        // TODO: switch to fatal error in Moodle 2.3
        //print_error('missingparam', '', '', $parname);
        return required_param_array($parname, $type);
    }

    return clean_param($param, $type);
}

function required_param_array($parname, $type) {
    if (func_num_args() != 2 or empty($parname) or empty($type)) {
        throw new coding_exception('required_param_array() requires $parname and $type to be specified (parameter: '.$parname.')');
    }
    if (isset($_POST[$parname])) {       // POST has precedence
        $param = $_POST[$parname];
    } else if (isset($_GET[$parname])) {
        $param = $_GET[$parname];
    } else {
        print_error('missingparam', '', '', $parname);
    }
    if (!is_array($param)) {
        print_error('missingparam', '', '', $parname);
    }

    $result = array();
    foreach($param as $key=>$value) {
        if (!preg_match('/^[a-z0-9_-]+$/i', $key)) {
            debugging('Invalid key name in required_param_array() detected: '.$key.', parameter: '.$parname);
            continue;
        }
        $result[$key] = clean_param($value, $type);
    }

    return $result;
}

function optional_param($parname, $default, $type) {
    if (func_num_args() != 3 or empty($parname) or empty($type)) {
        throw new coding_exception('optional_param() requires $parname, $default and $type to be specified (parameter: '.$parname.')');
    }
    if (!isset($default)) {
        $default = null;
    }

    if (isset($_POST[$parname])) {       // POST has precedence
        $param = $_POST[$parname];
    } else if (isset($_GET[$parname])) {
        $param = $_GET[$parname];
    } else {
        return $default;
    }

    if (is_array($param)) {
        debugging('Invalid array parameter detected in required_param(): '.$parname);
        // TODO: switch to $default in Moodle 2.3
        //return $default;
        return optional_param_array($parname, $default, $type);
    }

    return clean_param($param, $type);
}

function optional_param_array($parname, $default, $type) {
    if (func_num_args() != 3 or empty($parname) or empty($type)) {
        throw new coding_exception('optional_param_array() requires $parname, $default and $type to be specified (parameter: '.$parname.')');
    }

    if (isset($_POST[$parname])) {       // POST has precedence
        $param = $_POST[$parname];
    } else if (isset($_GET[$parname])) {
        $param = $_GET[$parname];
    } else {
        return $default;
    }
    if (!is_array($param)) {
        debugging('optional_param_array() expects array parameters only: '.$parname);
        return $default;
    }

    $result = array();
    foreach($param as $key=>$value) {
        if (!preg_match('/^[a-z0-9_-]+$/i', $key)) {
            debugging('Invalid key name in optional_param_array() detected: '.$key.', parameter: '.$parname);
            continue;
        }
        $result[$key] = clean_param($value, $type);
    }

    return $result;
}

function validate_param($param, $type, $allownull=NULL_NOT_ALLOWED, $debuginfo='') {
    if (is_null($param)) {
        if ($allownull == NULL_ALLOWED) {
            return null;
        } else {
            throw new invalid_parameter_exception($debuginfo);
        }
    }
    if (is_array($param) or is_object($param)) {
        throw new invalid_parameter_exception($debuginfo);
    }

    $cleaned = clean_param($param, $type);
    if ((string)$param !== (string)$cleaned) {
        // conversion to string is usually lossless
        throw new invalid_parameter_exception($debuginfo);
    }

    return $cleaned;
}

function clean_param_array(array $param = null, $type, $recursive = false) {
    $param = (array)$param; // convert null to empty array
    foreach ($param as $key => $value) {
        if (is_array($value)) {
            if ($recursive) {
                $param[$key] = clean_param_array($value, $type, true);
            } else {
                throw new coding_exception('clean_param_array() can not process multidimensional arrays when $recursive is false.');
            }
        } else {
            $param[$key] = clean_param($value, $type);
        }
    }
    return $param;
}

function clean_param($param, $type) {

    global $CFG;

    if (is_array($param)) {
        throw new coding_exception('clean_param() can not process arrays, please use clean_param_array() instead.');
    } else if (is_object($param)) {
        if (method_exists($param, '__toString')) {
            $param = $param->__toString();
        } else {
            throw new coding_exception('clean_param() can not process objects, please use clean_param_array() instead.');
        }
    }

    switch ($type) {
        case PARAM_RAW:          // no cleaning at all
            $param = fix_utf8($param);
            return $param;

        case PARAM_RAW_TRIMMED:         // no cleaning, but strip leading and trailing whitespace.
            $param = fix_utf8($param);
            return trim($param);

        case PARAM_CLEAN:        // General HTML cleaning, try to use more specific type if possible
            // this is deprecated!, please use more specific type instead
            if (is_numeric($param)) {
                return $param;
            }
            $param = fix_utf8($param);
            return clean_text($param);     // Sweep for scripts, etc

        case PARAM_CLEANHTML:    // clean html fragment
            $param = fix_utf8($param);
            $param = clean_text($param, FORMAT_HTML);     // Sweep for scripts, etc
            return trim($param);

        case PARAM_INT:
            return (int)$param;  // Convert to integer

        case PARAM_FLOAT:
        case PARAM_NUMBER:
            return (float)$param;  // Convert to float

        case PARAM_ALPHA:        // Remove everything not a-z
            return preg_replace('/[^a-zA-Z]/i', '', $param);

        case PARAM_ALPHAEXT:     // Remove everything not a-zA-Z_- (originally allowed "/" too)
            return preg_replace('/[^a-zA-Z_-]/i', '', $param);

        case PARAM_ALPHANUM:     // Remove everything not a-zA-Z0-9
            return preg_replace('/[^A-Za-z0-9]/i', '', $param);

        case PARAM_ALPHANUMEXT:     // Remove everything not a-zA-Z0-9_-
            return preg_replace('/[^A-Za-z0-9_-]/i', '', $param);

        case PARAM_SEQUENCE:     // Remove everything not 0-9,
            return preg_replace('/[^0-9,]/i', '', $param);

        case PARAM_BOOL:         // Convert to 1 or 0
            $tempstr = strtolower($param);
            if ($tempstr === 'on' or $tempstr === 'yes' or $tempstr === 'true') {
                $param = 1;
            } else if ($tempstr === 'off' or $tempstr === 'no'  or $tempstr === 'false') {
                $param = 0;
            } else {
                $param = empty($param) ? 0 : 1;
            }
            return $param;

        case PARAM_NOTAGS:       // Strip all tags
            $param = fix_utf8($param);
            return strip_tags($param);

        case PARAM_TEXT:    // leave only tags needed for multilang
            $param = fix_utf8($param);
            // if the multilang syntax is not correct we strip all tags
            // because it would break xhtml strict which is required for accessibility standards
            // please note this cleaning does not strip unbalanced '>' for BC compatibility reasons
            do {
                if (strpos($param, '</lang>') !== false) {
                    // old and future mutilang syntax
                    $param = strip_tags($param, '<lang>');
                    if (!preg_match_all('/<.*>/suU', $param, $matches)) {
                        break;
                    }
                    $open = false;
                    foreach ($matches[0] as $match) {
                        if ($match === '</lang>') {
                            if ($open) {
                                $open = false;
                                continue;
                            } else {
                                break 2;
                            }
                        }
                        if (!preg_match('/^<lang lang="[a-zA-Z0-9_-]+"\s*>$/u', $match)) {
                            break 2;
                        } else {
                            $open = true;
                        }
                    }
                    if ($open) {
                        break;
                    }
                    return $param;

                } else if (strpos($param, '</span>') !== false) {
                    // current problematic multilang syntax
                    $param = strip_tags($param, '<span>');
                    if (!preg_match_all('/<.*>/suU', $param, $matches)) {
                        break;
                    }
                    $open = false;
                    foreach ($matches[0] as $match) {
                        if ($match === '</span>') {
                            if ($open) {
                                $open = false;
                                continue;
                            } else {
                                break 2;
                            }
                        }
                        if (!preg_match('/^<span(\s+lang="[a-zA-Z0-9_-]+"|\s+class="multilang"){2}\s*>$/u', $match)) {
                            break 2;
                        } else {
                            $open = true;
                        }
                    }
                    if ($open) {
                        break;
                    }
                    return $param;
                }
            } while (false);
            // easy, just strip all tags, if we ever want to fix orphaned '&' we have to do that in format_string()
            return strip_tags($param);

        case PARAM_COMPONENT:
            // we do not want any guessing here, either the name is correct or not
            // please note only normalised component names are accepted
            if (!preg_match('/^[a-z]+(_[a-z][a-z0-9_]*)?[a-z0-9]$/', $param)) {
                return '';
            }
            if (strpos($param, '__') !== false) {
                return '';
            }
            if (strpos($param, 'mod_') === 0) {
                // module names must not contain underscores because we need to differentiate them from invalid plugin types
                if (substr_count($param, '_') != 1) {
                    return '';
                }
            }
            return $param;

        case PARAM_PLUGIN:
        case PARAM_AREA:
            // we do not want any guessing here, either the name is correct or not
            if (!preg_match('/^[a-z][a-z0-9_]*[a-z0-9]$/', $param)) {
                return '';
            }
            if (strpos($param, '__') !== false) {
                return '';
            }
            return $param;

        case PARAM_SAFEDIR:      // Remove everything not a-zA-Z0-9_-
            return preg_replace('/[^a-zA-Z0-9_-]/i', '', $param);

        case PARAM_SAFEPATH:     // Remove everything not a-zA-Z0-9/_-
            return preg_replace('/[^a-zA-Z0-9\/_-]/i', '', $param);

        case PARAM_FILE:         // Strip all suspicious characters from filename
            $param = fix_utf8($param);
            $param = preg_replace('~[[:cntrl:]]|[&<>"`\|\':\\\\/]~u', '', $param);
            $param = preg_replace('~\.\.+~', '', $param);
            if ($param === '.') {
                $param = '';
            }
            return $param;

        case PARAM_PATH:         // Strip all suspicious characters from file path
            $param = fix_utf8($param);
            $param = str_replace('\\', '/', $param);
            $param = preg_replace('~[[:cntrl:]]|[&<>"`\|\':]~u', '', $param);
            $param = preg_replace('~\.\.+~', '', $param);
            $param = preg_replace('~//+~', '/', $param);
            return preg_replace('~/(\./)+~', '/', $param);

        case PARAM_HOST:         // allow FQDN or IPv4 dotted quad
            $param = preg_replace('/[^\.\d\w-]/','', $param ); // only allowed chars
            // match ipv4 dotted quad
            if (preg_match('/(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/',$param, $match)){
                // confirm values are ok
                if ( $match[0] > 255
                     || $match[1] > 255
                     || $match[3] > 255
                     || $match[4] > 255 ) {
                    // hmmm, what kind of dotted quad is this?
                    $param = '';
                }
            } elseif ( preg_match('/^[\w\d\.-]+$/', $param) // dots, hyphens, numbers
                       && !preg_match('/^[\.-]/',  $param) // no leading dots/hyphens
                       && !preg_match('/[\.-]$/',  $param) // no trailing dots/hyphens
                       ) {
                // all is ok - $param is respected
            } else {
                // all is not ok...
                $param='';
            }
            return $param;

        case PARAM_URL:          // allow safe ftp, http, mailto urls
            $param = fix_utf8($param);
            include_once($CFG->dirroot . '/lib/validateurlsyntax.php');
            if (!empty($param) && validateUrlSyntax($param, 's?H?S?F?E?u-P-a?I?p?f?q?r?')) {
                // all is ok, param is respected
            } else {
                $param =''; // not really ok
            }
            return $param;

        case PARAM_LOCALURL:     // allow http absolute, root relative and relative URLs within wwwroot
            $param = clean_param($param, PARAM_URL);
            if (!empty($param)) {
                if (preg_match(':^/:', $param)) {
                    // root-relative, ok!
                } elseif (preg_match('/^'.preg_quote($CFG->wwwroot, '/').'/i',$param)) {
                    // absolute, and matches our wwwroot
                } else {
                    // relative - let's make sure there are no tricks
                    if (validateUrlSyntax('/' . $param, 's-u-P-a-p-f+q?r?')) {
                        // looks ok.
                    } else {
                        $param = '';
                    }
                }
            }
            return $param;

        case PARAM_PEM:
            $param = trim($param);
            // PEM formatted strings may contain letters/numbers and the symbols
            // forward slash: /
            // plus sign:     +
            // equal sign:    =
            // , surrounded by BEGIN and END CERTIFICATE prefix and suffixes
            if (preg_match('/^-----BEGIN CERTIFICATE-----([\s\w\/\+=]+)-----END CERTIFICATE-----$/', trim($param), $matches)) {
                list($wholething, $body) = $matches;
                unset($wholething, $matches);
                $b64 = clean_param($body, PARAM_BASE64);
                if (!empty($b64)) {
                    return "-----BEGIN CERTIFICATE-----\n$b64\n-----END CERTIFICATE-----\n";
                } else {
                    return '';
                }
            }
            return '';

        case PARAM_BASE64:
            if (!empty($param)) {
                // PEM formatted strings may contain letters/numbers and the symbols
                // forward slash: /
                // plus sign:     +
                // equal sign:    =
                if (0 >= preg_match('/^([\s\w\/\+=]+)$/', trim($param))) {
                    return '';
                }
                $lines = preg_split('/[\s]+/', $param, -1, PREG_SPLIT_NO_EMPTY);
                // Each line of base64 encoded data must be 64 characters in
                // length, except for the last line which may be less than (or
                // equal to) 64 characters long.
                for ($i=0, $j=count($lines); $i < $j; $i++) {
                    if ($i + 1 == $j) {
                        if (64 < strlen($lines[$i])) {
                            return '';
                        }
                        continue;
                    }

                    if (64 != strlen($lines[$i])) {
                        return '';
                    }
                }
                return implode("\n",$lines);
            } else {
                return '';
            }

        case PARAM_TAG:
            $param = fix_utf8($param);
            // Please note it is not safe to use the tag name directly anywhere,
            // it must be processed with s(), urlencode() before embedding anywhere.
            // remove some nasties
            $param = preg_replace('~[[:cntrl:]]|[<>`]~u', '', $param);
            //convert many whitespace chars into one
            $param = preg_replace('/\s+/', ' ', $param);
            $textlib = textlib_get_instance();
            $param = $textlib->substr(trim($param), 0, TAG_MAX_LENGTH);
            return $param;

        case PARAM_TAGLIST:
            $param = fix_utf8($param);
            $tags = explode(',', $param);
            $result = array();
            foreach ($tags as $tag) {
                $res = clean_param($tag, PARAM_TAG);
                if ($res !== '') {
                    $result[] = $res;
                }
            }
            if ($result) {
                return implode(',', $result);
            } else {
                return '';
            }

        case PARAM_CAPABILITY:
            if (get_capability_info($param)) {
                return $param;
            } else {
                return '';
            }

        case PARAM_PERMISSION:
            $param = (int)$param;
            if (in_array($param, array(CAP_INHERIT, CAP_ALLOW, CAP_PREVENT, CAP_PROHIBIT))) {
                return $param;
            } else {
                return CAP_INHERIT;
            }

        case PARAM_AUTH:
            $param = clean_param($param, PARAM_PLUGIN);
            if (empty($param)) {
                return '';
            } else if (exists_auth_plugin($param)) {
                return $param;
            } else {
                return '';
            }

        case PARAM_LANG:
            $param = clean_param($param, PARAM_SAFEDIR);
            if (get_string_manager()->translation_exists($param)) {
                return $param;
            } else {
                return ''; // Specified language is not installed or param malformed
            }

        case PARAM_THEME:
            $param = clean_param($param, PARAM_PLUGIN);
            if (empty($param)) {
                return '';
            } else if (file_exists("$CFG->dirroot/theme/$param/config.php")) {
                return $param;
            } else if (!empty($CFG->themedir) and file_exists("$CFG->themedir/$param/config.php")) {
                return $param;
            } else {
                return '';  // Specified theme is not installed
            }

        case PARAM_USERNAME:
            $param = fix_utf8($param);
            $param = str_replace(" " , "", $param);
            $param = moodle_strtolower($param);  // Convert uppercase to lowercase MDL-16919
            if (empty($CFG->extendedusernamechars)) {
                // regular expression, eliminate all chars EXCEPT:
                // alphanum, dash (-), underscore (_), at sign (@) and period (.) characters.
                $param = preg_replace('/[^-\.@_a-z0-9]/', '', $param);
            }
            return $param;

        case PARAM_EMAIL:
            $param = fix_utf8($param);
            if (validate_email($param)) {
                return $param;
            } else {
                return '';
            }

        case PARAM_STRINGID:
            if (preg_match('|^[a-zA-Z][a-zA-Z0-9\.:/_-]*$|', $param)) {
                return $param;
            } else {
                return '';
            }

        case PARAM_TIMEZONE:    //can be int, float(with .5 or .0) or string seperated by '/' and can have '-_'
            $param = fix_utf8($param);
            $timezonepattern = '/^(([+-]?(0?[0-9](\.[5|0])?|1[0-3]|1[0-2]\.5))|(99)|[[:alnum:]]+(\/?[[:alpha:]_-])+)$/';
            if (preg_match($timezonepattern, $param)) {
                return $param;
            } else {
                return '';
            }

        default:                 // throw error, switched parameters in optional_param or another serious problem
            print_error("unknownparamtype", '', '', $type);
    }
}

function fix_utf8($value) {
    if (is_null($value) or $value === '') {
        return $value;

    } else if (is_string($value)) {
        if ((string)(int)$value === $value) {
            // shortcut
            return $value;
        }
        return iconv('UTF-8', 'UTF-8//IGNORE', $value);

    } else if (is_array($value)) {
        foreach ($value as $k=>$v) {
            $value[$k] = fix_utf8($v);
        }
        return $value;

    } else if (is_object($value)) {
        $value = clone($value); // do not modify original
        foreach ($value as $k=>$v) {
            $value->$k = fix_utf8($v);
        }
        return $value;

    } else {
        // this is some other type, no utf-8 here
        return $value;
    }
}

function is_number($value) {
    if (is_int($value)) {
        return true;
    } else if (is_string($value)) {
        return ((string)(int)$value) === $value;
    } else {
        return false;
    }
}

function get_host_from_url($url) {
    preg_match('|^[a-z]+://([a-zA-Z0-9-.]+)|i', $url, $matches);
    if ($matches) {
        return $matches[1];
    }
    return null;
}

function html_is_blank($string) {
    return trim(strip_tags($string, '<img><object><applet><input><select><textarea><hr>')) == '';
}

function set_config($name, $value, $plugin=NULL) {
    global $CFG, $DB;

    if (empty($plugin)) {
        if (!array_key_exists($name, $CFG->config_php_settings)) {
            // So it's defined for this invocation at least
            if (is_null($value)) {
                unset($CFG->$name);
            } else {
                $CFG->$name = (string)$value; // settings from db are always strings
            }
        }

        if ($DB->get_field('config', 'name', array('name'=>$name))) {
            if ($value === null) {
                $DB->delete_records('config', array('name'=>$name));
            } else {
                $DB->set_field('config', 'value', $value, array('name'=>$name));
            }
        } else {
            if ($value !== null) {
                $config = new stdClass();
                $config->name  = $name;
                $config->value = $value;
                $DB->insert_record('config', $config, false);
            }
        }

    } else { // plugin scope
        if ($id = $DB->get_field('config_plugins', 'id', array('name'=>$name, 'plugin'=>$plugin))) {
            if ($value===null) {
                $DB->delete_records('config_plugins', array('name'=>$name, 'plugin'=>$plugin));
            } else {
                $DB->set_field('config_plugins', 'value', $value, array('id'=>$id));
            }
        } else {
            if ($value !== null) {
                $config = new stdClass();
                $config->plugin = $plugin;
                $config->name   = $name;
                $config->value  = $value;
                $DB->insert_record('config_plugins', $config, false);
            }
        }
    }

    return true;
}

function get_config($plugin, $name = NULL) {
    global $CFG, $DB;

    // normalise component name
    if ($plugin === 'moodle' or $plugin === 'core') {
        $plugin = NULL;
    }

    if (!empty($name)) { // the user is asking for a specific value
        if (!empty($plugin)) {
            if (isset($CFG->forced_plugin_settings[$plugin]) and array_key_exists($name, $CFG->forced_plugin_settings[$plugin])) {
                // setting forced in config file
                return $CFG->forced_plugin_settings[$plugin][$name];
            } else {
                return $DB->get_field('config_plugins', 'value', array('plugin'=>$plugin, 'name'=>$name));
            }
        } else {
            if (array_key_exists($name, $CFG->config_php_settings)) {
                // setting force in config file
                return $CFG->config_php_settings[$name];
            } else {
                return $DB->get_field('config', 'value', array('name'=>$name));
            }
        }
    }

    // the user is after a recordset
    if ($plugin) {
        $localcfg = $DB->get_records_menu('config_plugins', array('plugin'=>$plugin), '', 'name,value');
        if (isset($CFG->forced_plugin_settings[$plugin])) {
            foreach($CFG->forced_plugin_settings[$plugin] as $n=>$v) {
                if (is_null($v) or is_array($v) or is_object($v)) {
                    // we do not want any extra mess here, just real settings that could be saved in db
                    unset($localcfg[$n]);
                } else {
                    //convert to string as if it went through the DB
                    $localcfg[$n] = (string)$v;
                }
            }
        }
        if ($localcfg) {
            return (object)$localcfg;
        } else {
            return new stdClass();
        }

    } else {
        // this part is not really used any more, but anyway...
        $localcfg = $DB->get_records_menu('config', array(), '', 'name,value');
        foreach($CFG->config_php_settings as $n=>$v) {
            if (is_null($v) or is_array($v) or is_object($v)) {
                // we do not want any extra mess here, just real settings that could be saved in db
                unset($localcfg[$n]);
            } else {
                //convert to string as if it went through the DB
                $localcfg[$n] = (string)$v;
            }
        }
        return (object)$localcfg;
    }
}

function unset_config($name, $plugin=NULL) {
    global $CFG, $DB;

    if (empty($plugin)) {
        unset($CFG->$name);
        $DB->delete_records('config', array('name'=>$name));
    } else {
        $DB->delete_records('config_plugins', array('name'=>$name, 'plugin'=>$plugin));
    }

    return true;
}

function unset_all_config_for_plugin($plugin) {
    global $DB;
    $DB->delete_records('config_plugins', array('plugin' => $plugin));
    $like = $DB->sql_like('name', '?', true, true, false, '|');
    $params = array($DB->sql_like_escape($plugin.'_', '|') . '%');
    $DB->delete_records_select('config', $like, $params);
    return true;
}

function get_users_from_config($value, $capability, $includeadmins = true) {
    global $CFG, $DB;

    if (empty($value) or $value === '$@NONE@$') {
        return array();
    }

    // we have to make sure that users still have the necessary capability,
    // it should be faster to fetch them all first and then test if they are present
    // instead of validating them one-by-one
    $users = get_users_by_capability(get_context_instance(CONTEXT_SYSTEM), $capability);
    if ($includeadmins) {
        $admins = get_admins();
        foreach ($admins as $admin) {
            $users[$admin->id] = $admin;
        }
    }

    if ($value === '$@ALL@$') {
        return $users;
    }

    $result = array(); // result in correct order
    $allowed = explode(',', $value);
    foreach ($allowed as $uid) {
        if (isset($users[$uid])) {
            $user = $users[$uid];
            $result[$user->id] = $user;
        }
    }

    return $result;
}


function purge_all_caches() {
    global $CFG;

    reset_text_filters_cache();
    js_reset_all_caches();
    theme_reset_all_caches();
    get_string_manager()->reset_caches();

    // purge all other caches: rss, simplepie, etc.
    remove_dir($CFG->cachedir.'', true);

    // make sure cache dir is writable, throws exception if not
    make_cache_directory('');

    // hack: this script may get called after the purifier was initialised,
    // but we do not want to verify repeatedly this exists in each call
    make_cache_directory('htmlpurifier');
}

function get_cache_flags($type, $changedsince=NULL) {
    global $DB;

    $params = array('type'=>$type, 'expiry'=>time());
    $sqlwhere = "flagtype = :type AND expiry >= :expiry";
    if ($changedsince !== NULL) {
        $params['changedsince'] = $changedsince;
        $sqlwhere .= " AND timemodified > :changedsince";
    }
    $cf = array();

    if ($flags = $DB->get_records_select('cache_flags', $sqlwhere, $params, '', 'name,value')) {
        foreach ($flags as $flag) {
            $cf[$flag->name] = $flag->value;
        }
    }
    return $cf;
}

function get_cache_flag($type, $name, $changedsince=NULL) {
    global $DB;

    $params = array('type'=>$type, 'name'=>$name, 'expiry'=>time());

    $sqlwhere = "flagtype = :type AND name = :name AND expiry >= :expiry";
    if ($changedsince !== NULL) {
        $params['changedsince'] = $changedsince;
        $sqlwhere .= " AND timemodified > :changedsince";
    }

    return $DB->get_field_select('cache_flags', 'value', $sqlwhere, $params);
}

function set_cache_flag($type, $name, $value, $expiry=NULL) {
    global $DB;

    $timemodified = time();
    if ($expiry===NULL || $expiry < $timemodified) {
        $expiry = $timemodified + 24 * 60 * 60;
    } else {
        $expiry = (int)$expiry;
    }

    if ($value === NULL) {
        unset_cache_flag($type,$name);
        return true;
    }

    if ($f = $DB->get_record('cache_flags', array('name'=>$name, 'flagtype'=>$type), '*', IGNORE_MULTIPLE)) { // this is a potential problem in DEBUG_DEVELOPER
        if ($f->value == $value and $f->expiry == $expiry and $f->timemodified == $timemodified) {
            return true; //no need to update; helps rcache too
        }
        $f->value        = $value;
        $f->expiry       = $expiry;
        $f->timemodified = $timemodified;
        $DB->update_record('cache_flags', $f);
    } else {
        $f = new stdClass();
        $f->flagtype     = $type;
        $f->name         = $name;
        $f->value        = $value;
        $f->expiry       = $expiry;
        $f->timemodified = $timemodified;
        $DB->insert_record('cache_flags', $f);
    }
    return true;
}

function unset_cache_flag($type, $name) {
    global $DB;
    $DB->delete_records('cache_flags', array('name'=>$name, 'flagtype'=>$type));
    return true;
}

function gc_cache_flags() {
    global $DB;
    $DB->delete_records_select('cache_flags', 'expiry < ?', array(time()));
    return true;
}


function check_user_preferences_loaded(stdClass $user, $cachelifetime = 120) {
    global $DB;
    static $loadedusers = array(); // Static cache, we need to check on each page load, not only every 2 minutes.

    if (!isset($user->id)) {
        throw new coding_exception('Invalid $user parameter in check_user_preferences_loaded() call, missing id field');
    }

    if (empty($user->id) or isguestuser($user->id)) {
        // No permanent storage for not-logged-in users and guest
        if (!isset($user->preference)) {
            $user->preference = array();
        }
        return;
    }

    $timenow = time();

    if (isset($loadedusers[$user->id]) and isset($user->preference) and isset($user->preference['_lastloaded'])) {
        // Already loaded at least once on this page. Are we up to date?
        if ($user->preference['_lastloaded'] + $cachelifetime > $timenow) {
            // no need to reload - we are on the same page and we loaded prefs just a moment ago
            return;

        } else if (!get_cache_flag('userpreferenceschanged', $user->id, $user->preference['_lastloaded'])) {
            // no change since the lastcheck on this page
            $user->preference['_lastloaded'] = $timenow;
            return;
        }
    }

    // OK, so we have to reload all preferences
    $loadedusers[$user->id] = true;
    $user->preference = $DB->get_records_menu('user_preferences', array('userid'=>$user->id), '', 'name,value'); // All values
    $user->preference['_lastloaded'] = $timenow;
}

function mark_user_preferences_changed($userid) {
    global $CFG;

    if (empty($userid) or isguestuser($userid)) {
        // no cache flags for guest and not-logged-in users
        return;
    }

    set_cache_flag('userpreferenceschanged', $userid, 1, time() + $CFG->sessiontimeout);
}

function set_user_preference($name, $value, $user = null) {
    global $USER, $DB;

    if (empty($name) or is_numeric($name) or $name === '_lastloaded') {
        throw new coding_exception('Invalid preference name in set_user_preference() call');
    }

    if (is_null($value)) {
        // null means delete current
        return unset_user_preference($name, $user);
    } else if (is_object($value)) {
        throw new coding_exception('Invalid value in set_user_preference() call, objects are not allowed');
    } else if (is_array($value)) {
        throw new coding_exception('Invalid value in set_user_preference() call, arrays are not allowed');
    }
    $value = (string)$value;
    if (textlib::strlen($value) > 1333) { //value column maximum length is 1333 characters
        throw new coding_exception('Invalid value in set_user_preference() call, value is is too long for the value column');
    }

    if (is_null($user)) {
        $user = $USER;
    } else if (isset($user->id)) {
        // $user is valid object
    } else if (is_numeric($user)) {
        $user = (object)array('id'=>(int)$user);
    } else {
        throw new coding_exception('Invalid $user parameter in set_user_preference() call');
    }

    check_user_preferences_loaded($user);

    if (empty($user->id) or isguestuser($user->id)) {
        // no permanent storage for not-logged-in users and guest
        $user->preference[$name] = $value;
        return true;
    }

    if ($preference = $DB->get_record('user_preferences', array('userid'=>$user->id, 'name'=>$name))) {
        if ($preference->value === $value and isset($user->preference[$name]) and $user->preference[$name] === $value) {
            // preference already set to this value
            return true;
        }
        $DB->set_field('user_preferences', 'value', $value, array('id'=>$preference->id));

    } else {
        $preference = new stdClass();
        $preference->userid = $user->id;
        $preference->name   = $name;
        $preference->value  = $value;
        $DB->insert_record('user_preferences', $preference);
    }

    // update value in cache
    $user->preference[$name] = $value;

    // set reload flag for other sessions
    mark_user_preferences_changed($user->id);

    return true;
}

function set_user_preferences(array $prefarray, $user = null) {
    foreach ($prefarray as $name => $value) {
        set_user_preference($name, $value, $user);
    }
    return true;
}

function unset_user_preference($name, $user = null) {
    global $USER, $DB;

    if (empty($name) or is_numeric($name) or $name === '_lastloaded') {
        throw new coding_exception('Invalid preference name in unset_user_preference() call');
    }

    if (is_null($user)) {
        $user = $USER;
    } else if (isset($user->id)) {
        // $user is valid object
    } else if (is_numeric($user)) {
        $user = (object)array('id'=>(int)$user);
    } else {
        throw new coding_exception('Invalid $user parameter in unset_user_preference() call');
    }

    check_user_preferences_loaded($user);

    if (empty($user->id) or isguestuser($user->id)) {
        // no permanent storage for not-logged-in user and guest
        unset($user->preference[$name]);
        return true;
    }

    // delete from DB
    $DB->delete_records('user_preferences', array('userid'=>$user->id, 'name'=>$name));

    // delete the preference from cache
    unset($user->preference[$name]);

    // set reload flag for other sessions
    mark_user_preferences_changed($user->id);

    return true;
}

function get_user_preferences($name = null, $default = null, $user = null) {
    global $USER;

    if (is_null($name)) {
        // all prefs
    } else if (is_numeric($name) or $name === '_lastloaded') {
        throw new coding_exception('Invalid preference name in get_user_preferences() call');
    }

    if (is_null($user)) {
        $user = $USER;
    } else if (isset($user->id)) {
        // $user is valid object
    } else if (is_numeric($user)) {
        $user = (object)array('id'=>(int)$user);
    } else {
        throw new coding_exception('Invalid $user parameter in get_user_preferences() call');
    }

    check_user_preferences_loaded($user);

    if (empty($name)) {
        return $user->preference; // All values
    } else if (isset($user->preference[$name])) {
        return $user->preference[$name]; // The single string value
    } else {
        return $default; // Default value (null if not specified)
    }
}


function make_timestamp($year, $month=1, $day=1, $hour=0, $minute=0, $second=0, $timezone=99, $applydst=true) {

    //save input timezone, required for dst offset check.
    $passedtimezone = $timezone;

    $timezone = get_user_timezone_offset($timezone);

    if (abs($timezone) > 13) {  //server time
        $time = mktime((int)$hour, (int)$minute, (int)$second, (int)$month, (int)$day, (int)$year);
    } else {
        $time = gmmktime((int)$hour, (int)$minute, (int)$second, (int)$month, (int)$day, (int)$year);
        $time = usertime($time, $timezone);

        //Apply dst for string timezones or if 99 then try dst offset with user's default timezone
        if ($applydst && ((99 == $passedtimezone) || !is_numeric($passedtimezone))) {
            $time -= dst_offset_on($time, $passedtimezone);
        }
    }

    return $time;

}

 function format_time($totalsecs, $str=NULL) {

    $totalsecs = abs($totalsecs);

    if (!$str) {  // Create the str structure the slow way
        $str = new stdClass();
        $str->day   = get_string('day');
        $str->days  = get_string('days');
        $str->hour  = get_string('hour');
        $str->hours = get_string('hours');
        $str->min   = get_string('min');
        $str->mins  = get_string('mins');
        $str->sec   = get_string('sec');
        $str->secs  = get_string('secs');
        $str->year  = get_string('year');
        $str->years = get_string('years');
    }


    $years     = floor($totalsecs/YEARSECS);
    $remainder = $totalsecs - ($years*YEARSECS);
    $days      = floor($remainder/DAYSECS);
    $remainder = $totalsecs - ($days*DAYSECS);
    $hours     = floor($remainder/HOURSECS);
    $remainder = $remainder - ($hours*HOURSECS);
    $mins      = floor($remainder/MINSECS);
    $secs      = $remainder - ($mins*MINSECS);

    $ss = ($secs == 1)  ? $str->sec  : $str->secs;
    $sm = ($mins == 1)  ? $str->min  : $str->mins;
    $sh = ($hours == 1) ? $str->hour : $str->hours;
    $sd = ($days == 1)  ? $str->day  : $str->days;
    $sy = ($years == 1)  ? $str->year  : $str->years;

    $oyears = '';
    $odays = '';
    $ohours = '';
    $omins = '';
    $osecs = '';

    if ($years)  $oyears  = $years .' '. $sy;
    if ($days)  $odays  = $days .' '. $sd;
    if ($hours) $ohours = $hours .' '. $sh;
    if ($mins)  $omins  = $mins .' '. $sm;
    if ($secs)  $osecs  = $secs .' '. $ss;

    if ($years) return trim($oyears .' '. $odays);
    if ($days)  return trim($odays .' '. $ohours);
    if ($hours) return trim($ohours .' '. $omins);
    if ($mins)  return trim($omins .' '. $osecs);
    if ($secs)  return $osecs;
    return get_string('now');
}

function userdate($date, $format = '', $timezone = 99, $fixday = true) {

    global $CFG;

    if (empty($format)) {
        $format = get_string('strftimedaydatetime', 'langconfig');
    }

    if (!empty($CFG->nofixday)) {  // Config.php can force %d not to be fixed.
        $fixday = false;
    } else if ($fixday) {
        $formatnoday = str_replace('%d', 'DD', $format);
        $fixday = ($formatnoday != $format);
    }

    //add daylight saving offset for string timezones only, as we can't get dst for
    //float values. if timezone is 99 (user default timezone), then try update dst.
    if ((99 == $timezone) || !is_numeric($timezone)) {
        $date += dst_offset_on($date, $timezone);
    }

    $timezone = get_user_timezone_offset($timezone);

    if (abs($timezone) > 13) {   
        if ($fixday) {
            $datestring = strftime($formatnoday, $date);
            $daystring  = ltrim(str_replace(array(' 0', ' '), '', strftime(' %d', $date)));
            $datestring = str_replace('DD', $daystring, $datestring);
        } else {
            $datestring = strftime($format, $date);
        }
    } else {
        $date += (int)($timezone * 3600);
        if ($fixday) {
            $datestring = gmstrftime($formatnoday, $date);
            $daystring  = ltrim(str_replace(array(' 0', ' '), '', gmstrftime(' %d', $date)));
            $datestring = str_replace('DD', $daystring, $datestring);
        } else {
            $datestring = gmstrftime($format, $date);
        }
    }


   if ($CFG->ostype == 'WINDOWS') {
       if ($localewincharset = get_string('localewincharset', 'langconfig')) {
           $textlib = textlib_get_instance();
           $datestring = $textlib->convert($datestring, $localewincharset, 'utf-8');
       }
   }

    return $datestring;
}

function usergetdate($time, $timezone=99) {

    //save input timezone, required for dst offset check.
    $passedtimezone = $timezone;

    $timezone = get_user_timezone_offset($timezone);

    if (abs($timezone) > 13) {    // Server time
        return getdate($time);
    }

    //add daylight saving offset for string timezones only, as we can't get dst for
    //float values. if timezone is 99 (user default timezone), then try update dst.
    if ($passedtimezone == 99 || !is_numeric($passedtimezone)) {
        $time += dst_offset_on($time, $passedtimezone);
    }

    $time += intval((float)$timezone * HOURSECS);

    $datestring = gmstrftime('%B_%A_%j_%Y_%m_%w_%d_%H_%M_%S', $time);

    //be careful to ensure the returned array matches that produced by getdate() above
    list(
        $getdate['month'],
        $getdate['weekday'],
        $getdate['yday'],
        $getdate['year'],
        $getdate['mon'],
        $getdate['wday'],
        $getdate['mday'],
        $getdate['hours'],
        $getdate['minutes'],
        $getdate['seconds']
    ) = explode('_', $datestring);

    return $getdate;
}

function usertime($date, $timezone=99) {

    $timezone = get_user_timezone_offset($timezone);

    if (abs($timezone) > 13) {
        return $date;
    }
    return $date - (int)($timezone * HOURSECS);
}

function usergetmidnight($date, $timezone=99) {

    $userdate = usergetdate($date, $timezone);

    // Time of midnight of this user's day, in GMT
    return make_timestamp($userdate['year'], $userdate['mon'], $userdate['mday'], 0, 0, 0, $timezone);

}

function usertimezone($timezone=99) {

    $tz = get_user_timezone($timezone);

    if (!is_float($tz)) {
        return $tz;
    }

    if(abs($tz) > 13) { // Server time
        return get_string('serverlocaltime');
    }

    if($tz == intval($tz)) {
        // Don't show .0 for whole hours
        $tz = intval($tz);
    }

    if($tz == 0) {
        return 'UTC';
    }
    else if($tz > 0) {
        return 'UTC+'.$tz;
    }
    else {
        return 'UTC'.$tz;
    }

}

function get_user_timezone_offset($tz = 99) {

    global $USER, $CFG;

    $tz = get_user_timezone($tz);

    if (is_float($tz)) {
        return $tz;
    } else {
        $tzrecord = get_timezone_record($tz);
        if (empty($tzrecord)) {
            return 99.0;
        }
        return (float)$tzrecord->gmtoff / HOURMINS;
    }
}

function get_timezone_offset($tz) {
    global $CFG;

    if ($tz == 99) {
        return false;
    }

    if (is_numeric($tz)) {
        return intval($tz * 60*60);
    }

    if (!$tzrecord = get_timezone_record($tz)) {
        return false;
    }
    return intval($tzrecord->gmtoff * 60);
}

function get_user_timezone($tz = 99) {
    global $USER, $CFG;

    $timezones = array(
        $tz,
        isset($CFG->forcetimezone) ? $CFG->forcetimezone : 99,
        isset($USER->timezone) ? $USER->timezone : 99,
        isset($CFG->timezone) ? $CFG->timezone : 99,
        );

    $tz = 99;

    while(($tz == '' || $tz == 99 || $tz == NULL) && $next = each($timezones)) {
        $tz = $next['value'];
    }

    return is_numeric($tz) ? (float) $tz : $tz;
}

function get_timezone_record($timezonename) {
    global $CFG, $DB;
    static $cache = NULL;

    if ($cache === NULL) {
        $cache = array();
    }

    if (isset($cache[$timezonename])) {
        return $cache[$timezonename];
    }

    return $cache[$timezonename] = $DB->get_record_sql('SELECT * FROM {timezone}
                                                        WHERE name = ? ORDER BY year DESC', array($timezonename), IGNORE_MULTIPLE);
}

function calculate_user_dst_table($from_year = NULL, $to_year = NULL, $strtimezone = NULL) {
    global $CFG, $SESSION, $DB;

    $usertz = get_user_timezone($strtimezone);

    if (is_float($usertz)) {
        // Trivial timezone, no DST
        return false;
    }

    if (!empty($SESSION->dst_offsettz) && $SESSION->dst_offsettz != $usertz) {
        // We have precalculated values, but the user's effective TZ has changed in the meantime, so reset
        unset($SESSION->dst_offsets);
        unset($SESSION->dst_range);
    }

    if (!empty($SESSION->dst_offsets) && empty($from_year) && empty($to_year)) {
        // Repeat calls which do not request specific year ranges stop here, we have already calculated the table
        // This will be the return path most of the time, pretty light computationally
        return true;
    }

    // Reaching here means we either need to extend our table or create it from scratch

    // Remember which TZ we calculated these changes for
    $SESSION->dst_offsettz = $usertz;

    if(empty($SESSION->dst_offsets)) {
        // If we 're creating from scratch, put the two guard elements in there
        $SESSION->dst_offsets = array(1 => NULL, 0 => NULL);
    }
    if(empty($SESSION->dst_range)) {
        // If creating from scratch
        $from = max((empty($from_year) ? intval(date('Y')) - 3 : $from_year), 1971);
        $to   = min((empty($to_year)   ? intval(date('Y')) + 3 : $to_year),   2035);

        // Fill in the array with the extra years we need to process
        $yearstoprocess = array();
        for($i = $from; $i <= $to; ++$i) {
            $yearstoprocess[] = $i;
        }

        // Take note of which years we have processed for future calls
        $SESSION->dst_range = array($from, $to);
    }
    else {
        // If needing to extend the table, do the same
        $yearstoprocess = array();

        $from = max((empty($from_year) ? $SESSION->dst_range[0] : $from_year), 1971);
        $to   = min((empty($to_year)   ? $SESSION->dst_range[1] : $to_year),   2035);

        if($from < $SESSION->dst_range[0]) {
            // Take note of which years we need to process and then note that we have processed them for future calls
            for($i = $from; $i < $SESSION->dst_range[0]; ++$i) {
                $yearstoprocess[] = $i;
            }
            $SESSION->dst_range[0] = $from;
        }
        if($to > $SESSION->dst_range[1]) {
            // Take note of which years we need to process and then note that we have processed them for future calls
            for($i = $SESSION->dst_range[1] + 1; $i <= $to; ++$i) {
                $yearstoprocess[] = $i;
            }
            $SESSION->dst_range[1] = $to;
        }
    }

    if(empty($yearstoprocess)) {
        // This means that there was a call requesting a SMALLER range than we have already calculated
        return true;
    }

    // From now on, we know that the array has at least the two guard elements, and $yearstoprocess has the years we need
    // Also, the array is sorted in descending timestamp order!

    // Get DB data

    static $presets_cache = array();
    if (!isset($presets_cache[$usertz])) {
        $presets_cache[$usertz] = $DB->get_records('timezone', array('name'=>$usertz), 'year DESC', 'year, gmtoff, dstoff, dst_month, dst_startday, dst_weekday, dst_skipweeks, dst_time, std_month, std_startday, std_weekday, std_skipweeks, std_time');
    }
    if(empty($presets_cache[$usertz])) {
        return false;
    }

    // Remove ending guard (first element of the array)
    reset($SESSION->dst_offsets);
    unset($SESSION->dst_offsets[key($SESSION->dst_offsets)]);

    // Add all required change timestamps
    foreach($yearstoprocess as $y) {
        // Find the record which is in effect for the year $y
        foreach($presets_cache[$usertz] as $year => $preset) {
            if($year <= $y) {
                break;
            }
        }

        $changes = dst_changes_for_year($y, $preset);

        if($changes === NULL) {
            continue;
        }
        if($changes['dst'] != 0) {
            $SESSION->dst_offsets[$changes['dst']] = $preset->dstoff * MINSECS;
        }
        if($changes['std'] != 0) {
            $SESSION->dst_offsets[$changes['std']] = 0;
        }
    }

    // Put in a guard element at the top
    $maxtimestamp = max(array_keys($SESSION->dst_offsets));
    $SESSION->dst_offsets[($maxtimestamp + DAYSECS)] = NULL; // DAYSECS is arbitrary, any "small" number will do

    // Sort again
    krsort($SESSION->dst_offsets);

    return true;
}

function dst_changes_for_year($year, $timezone) {

    if($timezone->dst_startday == 0 && $timezone->dst_weekday == 0 && $timezone->std_startday == 0 && $timezone->std_weekday == 0) {
        return NULL;
    }

    $monthdaydst = find_day_in_month($timezone->dst_startday, $timezone->dst_weekday, $timezone->dst_month, $year);
    $monthdaystd = find_day_in_month($timezone->std_startday, $timezone->std_weekday, $timezone->std_month, $year);

    list($dst_hour, $dst_min) = explode(':', $timezone->dst_time);
    list($std_hour, $std_min) = explode(':', $timezone->std_time);

    $timedst = make_timestamp($year, $timezone->dst_month, $monthdaydst, 0, 0, 0, 99, false);
    $timestd = make_timestamp($year, $timezone->std_month, $monthdaystd, 0, 0, 0, 99, false);

    // Instead of putting hour and minute in make_timestamp(), we add them afterwards.
    // This has the advantage of being able to have negative values for hour, i.e. for timezones
    // where GMT time would be in the PREVIOUS day than the local one on which DST changes.

    $timedst += $dst_hour * HOURSECS + $dst_min * MINSECS;
    $timestd += $std_hour * HOURSECS + $std_min * MINSECS;

    return array('dst' => $timedst, 0 => $timedst, 'std' => $timestd, 1 => $timestd);
}

function dst_offset_on($time, $strtimezone = NULL) {
    global $SESSION;

    if(!calculate_user_dst_table(NULL, NULL, $strtimezone) || empty($SESSION->dst_offsets)) {
        return 0;
    }

    reset($SESSION->dst_offsets);
    while(list($from, $offset) = each($SESSION->dst_offsets)) {
        if($from <= $time) {
            break;
        }
    }

    // This is the normal return path
    if($offset !== NULL) {
        return $offset;
    }

    // Reaching this point means we haven't calculated far enough, do it now:
    // Calculate extra DST changes if needed and recurse. The recursion always
    // moves toward the stopping condition, so will always end.

    if($from == 0) {
        // We need a year smaller than $SESSION->dst_range[0]
        if($SESSION->dst_range[0] == 1971) {
            return 0;
        }
        calculate_user_dst_table($SESSION->dst_range[0] - 5, NULL, $strtimezone);
        return dst_offset_on($time, $strtimezone);
    }
    else {
        // We need a year larger than $SESSION->dst_range[1]
        if($SESSION->dst_range[1] == 2035) {
            return 0;
        }
        calculate_user_dst_table(NULL, $SESSION->dst_range[1] + 5, $strtimezone);
        return dst_offset_on($time, $strtimezone);
    }
}

function find_day_in_month($startday, $weekday, $month, $year) {

    $daysinmonth = days_in_month($month, $year);

    if($weekday == -1) {
        // Don't care about weekday, so return:
        //    abs($startday) if $startday != -1
        //    $daysinmonth otherwise
        return ($startday == -1) ? $daysinmonth : abs($startday);
    }

    // From now on we 're looking for a specific weekday

    // Give "end of month" its actual value, since we know it
    if($startday == -1) {
        $startday = -1 * $daysinmonth;
    }

    // Starting from day $startday, the sign is the direction

    if($startday < 1) {

        $startday = abs($startday);
        $lastmonthweekday  = strftime('%w', mktime(12, 0, 0, $month, $daysinmonth, $year));

        // This is the last such weekday of the month
        $lastinmonth = $daysinmonth + $weekday - $lastmonthweekday;
        if($lastinmonth > $daysinmonth) {
            $lastinmonth -= 7;
        }

        // Find the first such weekday <= $startday
        while($lastinmonth > $startday) {
            $lastinmonth -= 7;
        }

        return $lastinmonth;

    }
    else {

        $indexweekday = strftime('%w', mktime(12, 0, 0, $month, $startday, $year));

        $diff = $weekday - $indexweekday;
        if($diff < 0) {
            $diff += 7;
        }

        // This is the first such weekday of the month equal to or after $startday
        $firstfromindex = $startday + $diff;

        return $firstfromindex;

    }
}

function days_in_month($month, $year) {
   return intval(date('t', mktime(12, 0, 0, $month, 1, $year)));
}

function dayofweek($day, $month, $year) {
    // I wonder if this is any different from
    // strftime('%w', mktime(12, 0, 0, $month, $daysinmonth, $year, 0));
    return intval(date('w', mktime(12, 0, 0, $month, $day, $year)));
}


function get_login_url() {
    global $CFG;

    $url = "$CFG->wwwroot/login/index.php";

    if (!empty($CFG->loginhttps)) {
        $url = str_replace('http:', 'https:', $url);
    }

    return $url;
}

function require_login($courseorid = NULL, $autologinguest = true, $cm = NULL, $setwantsurltome = true, $preventredirect = false) {
    global $CFG, $SESSION, $USER, $FULLME, $PAGE, $SITE, $DB, $OUTPUT;

    // setup global $COURSE, themes, language and locale
    if (!empty($courseorid)) {
        if (is_object($courseorid)) {
            $course = $courseorid;
        } else if ($courseorid == SITEID) {
            $course = clone($SITE);
        } else {
            $course = $DB->get_record('course', array('id' => $courseorid), '*', MUST_EXIST);
        }
        if ($cm) {
            if ($cm->course != $course->id) {
                throw new coding_exception('course and cm parameters in require_login() call do not match!!');
            }
            // make sure we have a $cm from get_fast_modinfo as this contains activity access details
            if (!($cm instanceof cm_info)) {
                // note: nearly all pages call get_fast_modinfo anyway and it does not make any
                // db queries so this is not really a performance concern, however it is obviously
                // better if you use get_fast_modinfo to get the cm before calling this.
                $modinfo = get_fast_modinfo($course);
                $cm = $modinfo->get_cm($cm->id);
            }
            $PAGE->set_cm($cm, $course); // set's up global $COURSE
            $PAGE->set_pagelayout('incourse');
        } else {
            $PAGE->set_course($course); // set's up global $COURSE
        }
    } else {
        // do not touch global $COURSE via $PAGE->set_course(),
        // the reasons is we need to be able to call require_login() at any time!!
        $course = $SITE;
        if ($cm) {
            throw new coding_exception('cm parameter in require_login() requires valid course parameter!');
        }
    }

    // If the user is not even logged in yet then make sure they are
    if (!isloggedin()) {
        if ($autologinguest and !empty($CFG->guestloginbutton) and !empty($CFG->autologinguests)) {
            if (!$guest = get_complete_user_data('id', $CFG->siteguest)) {
                // misconfigured site guest, just redirect to login page
                redirect(get_login_url());
                exit; // never reached
            }
            $lang = isset($SESSION->lang) ? $SESSION->lang : $CFG->lang;
            complete_user_login($guest);
            $USER->autologinguest = true;
            $SESSION->lang = $lang;
        } else {
            //NOTE: $USER->site check was obsoleted by session test cookie,
            //      $USER->confirmed test is in login/index.php
            if ($preventredirect) {
                throw new require_login_exception('You are not logged in');
            }

            if ($setwantsurltome) {
                // TODO: switch to PAGE->url
                $SESSION->wantsurl = $FULLME;
            }
            if (!empty($_SERVER['HTTP_REFERER'])) {
                $SESSION->fromurl  = $_SERVER['HTTP_REFERER'];
            }
            redirect(get_login_url());
            exit; // never reached
        }
    }

    // loginas as redirection if needed
    if ($course->id != SITEID and session_is_loggedinas()) {
        if ($USER->loginascontext->contextlevel == CONTEXT_COURSE) {
            if ($USER->loginascontext->instanceid != $course->id) {
                print_error('loginasonecourse', '', $CFG->wwwroot.'/course/view.php?id='.$USER->loginascontext->instanceid);
            }
        }
    }

    // check whether the user should be changing password (but only if it is REALLY them)
    if (get_user_preferences('auth_forcepasswordchange') && !session_is_loggedinas()) {
        $userauth = get_auth_plugin($USER->auth);
        if ($userauth->can_change_password() and !$preventredirect) {
            $SESSION->wantsurl = $FULLME;
            if ($changeurl = $userauth->change_password_url()) {
                //use plugin custom url
                redirect($changeurl);
            } else {
                //use moodle internal method
                if (empty($CFG->loginhttps)) {
                    redirect($CFG->wwwroot .'/login/change_password.php');
                } else {
                    $wwwroot = str_replace('http:','https:', $CFG->wwwroot);
                    redirect($wwwroot .'/login/change_password.php');
                }
            }
        } else {
            print_error('nopasswordchangeforced', 'auth');
        }
    }

    // Check that the user account is properly set up
    if (user_not_fully_set_up($USER)) {
        if ($preventredirect) {
            throw new require_login_exception('User not fully set-up');
        }
        $SESSION->wantsurl = $FULLME;
        redirect($CFG->wwwroot .'/user/edit.php?id='. $USER->id .'&amp;course='. SITEID);
    }

    // Make sure the USER has a sesskey set up. Used for CSRF protection.
    sesskey();

    // Do not bother admins with any formalities
    if (is_siteadmin()) {
        //set accesstime or the user will appear offline which messes up messaging
        user_accesstime_log($course->id);
        return;
    }

    // Check that the user has agreed to a site policy if there is one - do not test in case of admins
    if (!$USER->policyagreed and !is_siteadmin()) {
        if (!empty($CFG->sitepolicy) and !isguestuser()) {
            if ($preventredirect) {
                throw new require_login_exception('Policy not agreed');
            }
            $SESSION->wantsurl = $FULLME;
            redirect($CFG->wwwroot .'/user/policy.php');
        } else if (!empty($CFG->sitepolicyguest) and isguestuser()) {
            if ($preventredirect) {
                throw new require_login_exception('Policy not agreed');
            }
            $SESSION->wantsurl = $FULLME;
            redirect($CFG->wwwroot .'/user/policy.php');
        }
    }

    // Fetch the system context, the course context, and prefetch its child contexts
    $sysctx = get_context_instance(CONTEXT_SYSTEM);
    $coursecontext = get_context_instance(CONTEXT_COURSE, $course->id, MUST_EXIST);
    if ($cm) {
        $cmcontext = get_context_instance(CONTEXT_MODULE, $cm->id, MUST_EXIST);
    } else {
        $cmcontext = null;
    }

    // If the site is currently under maintenance, then print a message
    if (!empty($CFG->maintenance_enabled) and !has_capability('moodle/site:config', $sysctx)) {
        if ($preventredirect) {
            throw new require_login_exception('Maintenance in progress');
        }

        print_maintenance_message();
    }

    // make sure the course itself is not hidden
    if ($course->id == SITEID) {
        // frontpage can not be hidden
    } else {
        if (is_role_switched($course->id)) {
            // when switching roles ignore the hidden flag - user had to be in course to do the switch
        } else {
            if (!$course->visible and !has_capability('moodle/course:viewhiddencourses', $coursecontext)) {
                // originally there was also test of parent category visibility,
                // BUT is was very slow in complex queries involving "my courses"
                // now it is also possible to simply hide all courses user is not enrolled in :-)
                if ($preventredirect) {
                    throw new require_login_exception('Course is hidden');
                }
                // We need to override the navigation URL as the course won't have
                // been added to the navigation and thus the navigation will mess up
                // when trying to find it.
                navigation_node::override_active_url(new moodle_url('/'));
                notice(get_string('coursehidden'), $CFG->wwwroot .'/');
            }
        }
    }

    // is the user enrolled?
    if ($course->id == SITEID) {
        // everybody is enrolled on the frontpage

    } else {
        if (session_is_loggedinas()) {
            // Make sure the REAL person can access this course first
            $realuser = session_get_realuser();
            if (!is_enrolled($coursecontext, $realuser->id, '', true) and !is_viewing($coursecontext, $realuser->id) and !is_siteadmin($realuser->id)) {
                if ($preventredirect) {
                    throw new require_login_exception('Invalid course login-as access');
                }
                echo $OUTPUT->header();
                notice(get_string('studentnotallowed', '', fullname($USER, true)), $CFG->wwwroot .'/');
            }
        }

        $access = false;

        if (is_role_switched($course->id)) {
            // ok, user had to be inside this course before the switch
            $access = true;

        } else if (is_viewing($coursecontext, $USER)) {
            // ok, no need to mess with enrol
            $access = true;

        } else {
            if (isset($USER->enrol['enrolled'][$course->id])) {
                if ($USER->enrol['enrolled'][$course->id] > time()) {
                    $access = true;
                    if (isset($USER->enrol['tempguest'][$course->id])) {
                        unset($USER->enrol['tempguest'][$course->id]);
                        remove_temp_course_roles($coursecontext);
                    }
                } else {
                    //expired
                    unset($USER->enrol['enrolled'][$course->id]);
                }
            }
            if (isset($USER->enrol['tempguest'][$course->id])) {
                if ($USER->enrol['tempguest'][$course->id] == 0) {
                    $access = true;
                } else if ($USER->enrol['tempguest'][$course->id] > time()) {
                    $access = true;
                } else {
                    //expired
                    unset($USER->enrol['tempguest'][$course->id]);
                    remove_temp_course_roles($coursecontext);
                }
            }

            if ($access) {
                // cache ok
            } else {
                $until = enrol_get_enrolment_end($coursecontext->instanceid, $USER->id);
                if ($until !== false) {
                    // active participants may always access, a timestamp in the future, 0 (always) or false.
                    if ($until == 0) {
                        $until = ENROL_MAX_TIMESTAMP;
                    }
                    $USER->enrol['enrolled'][$course->id] = $until;
                    $access = true;

                } else {
                    $instances = $DB->get_records('enrol', array('courseid'=>$course->id, 'status'=>ENROL_INSTANCE_ENABLED), 'sortorder, id ASC');
                    $enrols = enrol_get_plugins(true);
                    // first ask all enabled enrol instances in course if they want to auto enrol user
                    foreach($instances as $instance) {
                        if (!isset($enrols[$instance->enrol])) {
                            continue;
                        }
                        // Get a duration for the enrolment, a timestamp in the future, 0 (always) or false.
                        $until = $enrols[$instance->enrol]->try_autoenrol($instance);
                        if ($until !== false) {
                            if ($until == 0) {
                                $until = ENROL_MAX_TIMESTAMP;
                            }
                            $USER->enrol['enrolled'][$course->id] = $until;
                            $access = true;
                            break;
                        }
                    }
                    // if not enrolled yet try to gain temporary guest access
                    if (!$access) {
                        foreach($instances as $instance) {
                            if (!isset($enrols[$instance->enrol])) {
                                continue;
                            }
                            // Get a duration for the guest access, a timestamp in the future or false.
                            $until = $enrols[$instance->enrol]->try_guestaccess($instance);
                            if ($until !== false and $until > time()) {
                                $USER->enrol['tempguest'][$course->id] = $until;
                                $access = true;
                                break;
                            }
                        }
                    }
                }
            }
        }

        if (!$access) {
            if ($preventredirect) {
                throw new require_login_exception('Not enrolled');
            }
            $SESSION->wantsurl = $FULLME;
            redirect($CFG->wwwroot .'/enrol/index.php?id='. $course->id);
        }
    }

    // Check visibility of activity to current user; includes visible flag, groupmembersonly,
    // conditional availability, etc
    if ($cm && !$cm->uservisible) {
        if ($preventredirect) {
            throw new require_login_exception('Activity is hidden');
        }
        redirect($CFG->wwwroot, get_string('activityiscurrentlyhidden'));
    }

    // Finally access granted, update lastaccess times
    user_accesstime_log($course->id);
}


function require_logout() {
    global $USER;

    $params = $USER;

    if (isloggedin()) {
        add_to_log(SITEID, "user", "logout", "view.php?id=$USER->id&course=".SITEID, $USER->id, 0, $USER->id);

        $authsequence = get_enabled_auth_plugins(); // auths, in sequence
        foreach($authsequence as $authname) {
            $authplugin = get_auth_plugin($authname);
            $authplugin->prelogout_hook();
        }
    }

    events_trigger('user_logout', $params);
    session_get_instance()->terminate_current();
    unset($params);
}

function require_course_login($courseorid, $autologinguest = true, $cm = NULL, $setwantsurltome = true, $preventredirect = false) {
    global $CFG, $PAGE, $SITE;
    $issite = (is_object($courseorid) and $courseorid->id == SITEID)
          or (!is_object($courseorid) and $courseorid == SITEID);
    if ($issite && !empty($cm) && !($cm instanceof cm_info)) {
        // note: nearly all pages call get_fast_modinfo anyway and it does not make any
        // db queries so this is not really a performance concern, however it is obviously
        // better if you use get_fast_modinfo to get the cm before calling this.
        if (is_object($courseorid)) {
            $course = $courseorid;
        } else {
            $course = clone($SITE);
        }
        $modinfo = get_fast_modinfo($course);
        $cm = $modinfo->get_cm($cm->id);
    }
    if (!empty($CFG->forcelogin)) {
        // login required for both SITE and courses
        require_login($courseorid, $autologinguest, $cm, $setwantsurltome, $preventredirect);

    } else if ($issite && !empty($cm) and !$cm->uservisible) {
        // always login for hidden activities
        require_login($courseorid, $autologinguest, $cm, $setwantsurltome, $preventredirect);

    } else if ($issite) {
              //login for SITE not required
        if ($cm and empty($cm->visible)) {
            // hidden activities are not accessible without login
            require_login($courseorid, $autologinguest, $cm, $setwantsurltome, $preventredirect);
        } else if ($cm and !empty($CFG->enablegroupmembersonly) and $cm->groupmembersonly) {
            // not-logged-in users do not have any group membership
            require_login($courseorid, $autologinguest, $cm, $setwantsurltome, $preventredirect);
        } else {
            // We still need to instatiate PAGE vars properly so that things
            // that rely on it like navigation function correctly.
            if (!empty($courseorid)) {
                if (is_object($courseorid)) {
                    $course = $courseorid;
                } else {
                    $course = clone($SITE);
                }
                if ($cm) {
                    if ($cm->course != $course->id) {
                        throw new coding_exception('course and cm parameters in require_course_login() call do not match!!');
                    }
                    $PAGE->set_cm($cm, $course);
                    $PAGE->set_pagelayout('incourse');
                } else {
                    $PAGE->set_course($course);
                }
            } else {
                // If $PAGE->course, and hence $PAGE->context, have not already been set
                // up properly, set them up now.
                $PAGE->set_course($PAGE->course);
            }
            //TODO: verify conditional activities here
            user_accesstime_log(SITEID);
            return;
        }

    } else {
        // course login always required
        require_login($courseorid, $autologinguest, $cm, $setwantsurltome, $preventredirect);
    }
}

function require_user_key_login($script, $instance=null) {
    global $USER, $SESSION, $CFG, $DB;

    if (!NO_MOODLE_COOKIES) {
        print_error('sessioncookiesdisable');
    }

    @session_write_close();

    $keyvalue = required_param('key', PARAM_ALPHANUM);

    if (!$key = $DB->get_record('user_private_key', array('script'=>$script, 'value'=>$keyvalue, 'instance'=>$instance))) {
        print_error('invalidkey');
    }

    if (!empty($key->validuntil) and $key->validuntil < time()) {
        print_error('expiredkey');
    }

    if ($key->iprestriction) {
        $remoteaddr = getremoteaddr(null);
        if (empty($remoteaddr) or !address_in_subnet($remoteaddr, $key->iprestriction)) {
            print_error('ipmismatch');
        }
    }

    if (!$user = $DB->get_record('user', array('id'=>$key->userid))) {
        print_error('invaliduserid');
    }

    enrol_check_plugins($user);
    session_set_user($user);

    if (!defined('USER_KEY_LOGIN')) {
        define('USER_KEY_LOGIN', true);
    }

    return $key->instance;
}

function create_user_key($script, $userid, $instance=null, $iprestriction=null, $validuntil=null) {
    global $DB;

    $key = new stdClass();
    $key->script        = $script;
    $key->userid        = $userid;
    $key->instance      = $instance;
    $key->iprestriction = $iprestriction;
    $key->validuntil    = $validuntil;
    $key->timecreated   = time();

    $key->value         = md5($userid.'_'.time().random_string(40)); // something long and unique
    while ($DB->record_exists('user_private_key', array('value'=>$key->value))) {
        // must be unique
        $key->value     = md5($userid.'_'.time().random_string(40));
    }
    $DB->insert_record('user_private_key', $key);
    return $key->value;
}

function delete_user_key($script,$userid) {
    global $DB;
    $DB->delete_records('user_private_key', array('script'=>$script, 'userid'=>$userid));
}

function get_user_key($script, $userid, $instance=null, $iprestriction=null, $validuntil=null) {
    global $DB;

    if ($key = $DB->get_record('user_private_key', array('script'=>$script, 'userid'=>$userid,
                                                         'instance'=>$instance, 'iprestriction'=>$iprestriction,
                                                         'validuntil'=>$validuntil))) {
        return $key->value;
    } else {
        return create_user_key($script, $userid, $instance, $iprestriction, $validuntil);
    }
}


function update_user_login_times() {
    global $USER, $DB;

    $user = new stdClass();
    $USER->lastlogin = $user->lastlogin = $USER->currentlogin;
    $USER->currentlogin = $user->lastaccess = $user->currentlogin = time();

    $user->id = $USER->id;

    $DB->update_record('user', $user);
    return true;
}

function user_not_fully_set_up($user) {
    if (isguestuser($user)) {
        return false;
    }
    return (empty($user->firstname) or empty($user->lastname) or empty($user->email) or over_bounce_threshold($user));
}

function over_bounce_threshold($user) {
    global $CFG, $DB;

    if (empty($CFG->handlebounces)) {
        return false;
    }

    if (empty($user->id)) { 
        return false;
    }

    // set sensible defaults
    if (empty($CFG->minbounces)) {
        $CFG->minbounces = 10;
    }
    if (empty($CFG->bounceratio)) {
        $CFG->bounceratio = .20;
    }
    $bouncecount = 0;
    $sendcount = 0;
    if ($bounce = $DB->get_record('user_preferences', array ('userid'=>$user->id, 'name'=>'email_bounce_count'))) {
        $bouncecount = $bounce->value;
    }
    if ($send = $DB->get_record('user_preferences', array('userid'=>$user->id, 'name'=>'email_send_count'))) {
        $sendcount = $send->value;
    }
    return ($bouncecount >= $CFG->minbounces && $bouncecount/$sendcount >= $CFG->bounceratio);
}

function set_send_count($user,$reset=false) {
    global $DB;

    if (empty($user->id)) { 
        return;
    }

    if ($pref = $DB->get_record('user_preferences', array('userid'=>$user->id, 'name'=>'email_send_count'))) {
        $pref->value = (!empty($reset)) ? 0 : $pref->value+1;
        $DB->update_record('user_preferences', $pref);
    }
    else if (!empty($reset)) { // if it's not there and we're resetting, don't bother.
        // make a new one
        $pref = new stdClass();
        $pref->name   = 'email_send_count';
        $pref->value  = 1;
        $pref->userid = $user->id;
        $DB->insert_record('user_preferences', $pref, false);
    }
}

function set_bounce_count($user,$reset=false) {
    global $DB;

    if ($pref = $DB->get_record('user_preferences', array('userid'=>$user->id, 'name'=>'email_bounce_count'))) {
        $pref->value = (!empty($reset)) ? 0 : $pref->value+1;
        $DB->update_record('user_preferences', $pref);
    }
    else if (!empty($reset)) { // if it's not there and we're resetting, don't bother.
        // make a new one
        $pref = new stdClass();
        $pref->name   = 'email_bounce_count';
        $pref->value  = 1;
        $pref->userid = $user->id;
        $DB->insert_record('user_preferences', $pref, false);
    }
}

function update_login_count() {
    global $SESSION;

    $max_logins = 10;

    if (empty($SESSION->logincount)) {
        $SESSION->logincount = 1;
    } else {
        $SESSION->logincount++;
    }

    if ($SESSION->logincount > $max_logins) {
        unset($SESSION->wantsurl);
        print_error('errortoomanylogins');
    }
}

function reset_login_count() {
    global $SESSION;

    $SESSION->logincount = 0;
}

function isediting() {
    global $PAGE;
    debugging('call to deprecated function isediting(). Please use $PAGE->user_is_editing() instead', DEBUG_DEVELOPER);
    return $PAGE->user_is_editing();
}

function ismoving($courseid) {
    global $USER;

    if (!empty($USER->activitycopy)) {
        return ($USER->activitycopycourse == $courseid);
    }
    return false;
}

function fullname($user, $override=false) {
    global $CFG, $SESSION;

    if (!isset($user->firstname) and !isset($user->lastname)) {
        return '';
    }

    if (!$override) {
        if (!empty($CFG->forcefirstname)) {
            $user->firstname = $CFG->forcefirstname;
        }
        if (!empty($CFG->forcelastname)) {
            $user->lastname = $CFG->forcelastname;
        }
    }

    if (!empty($SESSION->fullnamedisplay)) {
        $CFG->fullnamedisplay = $SESSION->fullnamedisplay;
    }

    if (!isset($CFG->fullnamedisplay) or $CFG->fullnamedisplay === 'firstname lastname') {
        return $user->firstname .' '. $user->lastname;

    } else if ($CFG->fullnamedisplay == 'lastname firstname') {
        return $user->lastname .' '. $user->firstname;

    } else if ($CFG->fullnamedisplay == 'firstname') {
        if ($override) {
            return get_string('fullnamedisplay', '', $user);
        } else {
            return $user->firstname;
        }
    }

    return get_string('fullnamedisplay', '', $user);
}

function get_extra_user_fields($context, $already = array()) {
    global $CFG;

    // Only users with permission get the extra fields
    if (!has_capability('moodle/site:viewuseridentity', $context)) {
        return array();
    }

    // Split showuseridentity on comma
    if (empty($CFG->showuseridentity)) {
        // Explode gives wrong result with empty string
        $extra = array();
    } else {
        $extra =  explode(',', $CFG->showuseridentity);
    }
    $renumber = false;
    foreach ($extra as $key => $field) {
        if (in_array($field, $already)) {
            unset($extra[$key]);
            $renumber = true;
        }
    }
    if ($renumber) {
        // For consistency, if entries are removed from array, renumber it
        // so they are numbered as you would expect
        $extra = array_merge($extra);
    }
    return $extra;
}

function get_extra_user_fields_sql($context, $alias='', $prefix='',
        $already = array()) {
    $fields = get_extra_user_fields($context, $already);
    $result = '';
    // Add punctuation for alias
    if ($alias !== '') {
        $alias .= '.';
    }
    foreach ($fields as $field) {
        $result .= ', ' . $alias . $field;
        if ($prefix) {
            $result .= ' AS ' . $prefix . $field;
        }
    }
    return $result;
}

function get_user_field_name($field) {
    // Some fields have language strings which are not the same as field name
    switch ($field) {
        case 'phone1' : return get_string('phone');
    }
    // Otherwise just use the same lang string
    return get_string($field);
}

function exists_auth_plugin($auth) {
    global $CFG;

    if (file_exists("{$CFG->dirroot}/auth/$auth/auth.php")) {
        return is_readable("{$CFG->dirroot}/auth/$auth/auth.php");
    }
    return false;
}

function is_enabled_auth($auth) {
    if (empty($auth)) {
        return false;
    }

    $enabled = get_enabled_auth_plugins();

    return in_array($auth, $enabled);
}

function get_auth_plugin($auth) {
    global $CFG;

    // check the plugin exists first
    if (! exists_auth_plugin($auth)) {
        print_error('authpluginnotfound', 'debug', '', $auth);
    }

    // return auth plugin instance
    require_once "{$CFG->dirroot}/auth/$auth/auth.php";
    $class = "auth_plugin_$auth";
    return new $class;
}

function get_enabled_auth_plugins($fix=false) {
    global $CFG;

    $default = array('manual', 'nologin');

    if (empty($CFG->auth)) {
        $auths = array();
    } else {
        $auths = explode(',', $CFG->auth);
    }

    if ($fix) {
        $auths = array_unique($auths);
        foreach($auths as $k=>$authname) {
            if (!exists_auth_plugin($authname) or in_array($authname, $default)) {
                unset($auths[$k]);
            }
        }
        $newconfig = implode(',', $auths);
        if (!isset($CFG->auth) or $newconfig != $CFG->auth) {
            set_config('auth', $newconfig);
        }
    }

    return (array_merge($default, $auths));
}

function is_internal_auth($auth) {
    $authplugin = get_auth_plugin($auth); // throws error if bad $auth
    return $authplugin->is_internal();
}

function is_restored_user($username) {
    global $CFG, $DB;

    return $DB->record_exists('user', array('username'=>$username, 'mnethostid'=>$CFG->mnet_localhost_id, 'password'=>'restored'));
}

function get_user_fieldnames() {
    global $DB;

    $fieldarray = $DB->get_columns('user');
    unset($fieldarray['id']);
    $fieldarray = array_keys($fieldarray);

    return $fieldarray;
}

function create_user_record($username, $password, $auth = 'manual') {
    global $CFG, $DB;

    //just in case check text case
    $username = trim(moodle_strtolower($username));

    $authplugin = get_auth_plugin($auth);

    $newuser = new stdClass();

    if ($newinfo = $authplugin->get_userinfo($username)) {
        $newinfo = truncate_userinfo($newinfo);
        foreach ($newinfo as $key => $value){
            $newuser->$key = $value;
        }
    }

    if (!empty($newuser->email)) {
        if (email_is_not_allowed($newuser->email)) {
            unset($newuser->email);
        }
    }

    if (!isset($newuser->city)) {
        $newuser->city = '';
    }

    $newuser->auth = $auth;
    $newuser->username = $username;

    // fix for MDL-8480
    // user CFG lang for user if $newuser->lang is empty
    // or $user->lang is not an installed language
    if (empty($newuser->lang) || !get_string_manager()->translation_exists($newuser->lang)) {
        $newuser->lang = $CFG->lang;
    }
    $newuser->confirmed = 1;
    $newuser->lastip = getremoteaddr();
    $newuser->timecreated = time();
    $newuser->timemodified = $newuser->timecreated;
    $newuser->mnethostid = $CFG->mnet_localhost_id;

    $newuser->id = $DB->insert_record('user', $newuser);
    $user = get_complete_user_data('id', $newuser->id);
    if (!empty($CFG->{'auth_'.$newuser->auth.'_forcechangepassword'})){
        set_user_preference('auth_forcepasswordchange', 1, $user);
    }
    update_internal_user_password($user, $password);

    // fetch full user record for the event, the complete user data contains too much info
    // and we want to be consistent with other places that trigger this event
    events_trigger('user_created', $DB->get_record('user', array('id'=>$user->id)));

    return $user;
}

function update_user_record($username) {
    global $DB, $CFG;

    $username = trim(moodle_strtolower($username)); 

    $oldinfo = $DB->get_record('user', array('username'=>$username, 'mnethostid'=>$CFG->mnet_localhost_id), '*', MUST_EXIST);
    $newuser = array();
    $userauth = get_auth_plugin($oldinfo->auth);

    if ($newinfo = $userauth->get_userinfo($username)) {
        $newinfo = truncate_userinfo($newinfo);
        foreach ($newinfo as $key => $value){
            $key = strtolower($key);
            if (!property_exists($oldinfo, $key) or $key === 'username' or $key === 'id'
                    or $key === 'auth' or $key === 'mnethostid' or $key === 'deleted') {
                // unknown or must not be changed
                continue;
            }
            $confval = $userauth->config->{'field_updatelocal_' . $key};
            $lockval = $userauth->config->{'field_lock_' . $key};
            if (empty($confval) || empty($lockval)) {
                continue;
            }
            if ($confval === 'onlogin') {
                // MDL-4207 Don't overwrite modified user profile values with
                // empty LDAP values when 'unlocked if empty' is set. The purpose
                // of the setting 'unlocked if empty' is to allow the user to fill
                // in a value for the selected field _if LDAP is giving
                // nothing_ for this field. Thus it makes sense to let this value
                // stand in until LDAP is giving a value for this field.
                if (!(empty($value) && $lockval === 'unlockedifempty')) {
                    if ((string)$oldinfo->$key !== (string)$value) {
                        $newuser[$key] = (string)$value;
                    }
                }
            }
        }
        if ($newuser) {
            $newuser['id'] = $oldinfo->id;
            $newuser['timemodified'] = time();
            $DB->update_record('user', $newuser);
            // fetch full user record for the event, the complete user data contains too much info
            // and we want to be consistent with other places that trigger this event
            events_trigger('user_updated', $DB->get_record('user', array('id'=>$oldinfo->id)));
        }
    }

    return get_complete_user_data('id', $oldinfo->id);
}

function truncate_userinfo($info) {
    // define the limits
    $limit = array(
                    'username'    => 100,
                    'idnumber'    => 255,
                    'firstname'   => 100,
                    'lastname'    => 100,
                    'email'       => 100,
                    'icq'         =>  15,
                    'phone1'      =>  20,
                    'phone2'      =>  20,
                    'institution' =>  40,
                    'department'  =>  30,
                    'address'     =>  70,
                    'city'        => 120,
                    'country'     =>   2,
                    'url'         => 255,
                    );

    $textlib = textlib_get_instance();
    // apply where needed
    foreach (array_keys($info) as $key) {
        if (!empty($limit[$key])) {
            $info[$key] = trim($textlib->substr($info[$key],0, $limit[$key]));
        }
    }

    return $info;
}

function delete_user($user) {
    global $CFG, $DB;
    require_once($CFG->libdir.'/grouplib.php');
    require_once($CFG->libdir.'/gradelib.php');
    require_once($CFG->dirroot.'/message/lib.php');
    require_once($CFG->dirroot.'/tag/lib.php');

    // delete all grades - backup is kept in grade_grades_history table
    grade_user_delete($user->id);

    //move unread messages from this user to read
    message_move_userfrom_unread2read($user->id);

    // TODO: remove from cohorts using standard API here

    // remove user tags
    tag_set('user', $user->id, array());

    // unconditionally unenrol from all courses
    enrol_user_delete($user);

    // unenrol from all roles in all contexts
    role_unassign_all(array('userid'=>$user->id)); // this might be slow but it is really needed - modules might do some extra cleanup!

    //now do a brute force cleanup

    // remove from all cohorts
    $DB->delete_records('cohort_members', array('userid'=>$user->id));

    // remove from all groups
    $DB->delete_records('groups_members', array('userid'=>$user->id));

    // brute force unenrol from all courses
    $DB->delete_records('user_enrolments', array('userid'=>$user->id));

    // purge user preferences
    $DB->delete_records('user_preferences', array('userid'=>$user->id));

    // purge user extra profile info
    $DB->delete_records('user_info_data', array('userid'=>$user->id));

    // last course access not necessary either
    $DB->delete_records('user_lastaccess', array('userid'=>$user->id));

    // remove all user tokens
    $DB->delete_records('external_tokens', array('userid'=>$user->id));

    // unauthorise the user for all services
    $DB->delete_records('external_services_users', array('userid'=>$user->id));

    // force logout - may fail if file based sessions used, sorry
    session_kill_user($user->id);

    // now do a final accesslib cleanup - removes all role assignments in user context and context itself
    delete_context(CONTEXT_USER, $user->id);

    // workaround for bulk deletes of users with the same email address
    $delname = "$user->email.".time();
    while ($DB->record_exists('user', array('username'=>$delname))) { // no need to use mnethostid here
        $delname++;
    }

    // mark internal user record as "deleted"
    $updateuser = new stdClass();
    $updateuser->id           = $user->id;
    $updateuser->deleted      = 1;
    $updateuser->username     = $delname;            // Remember it just in case
    $updateuser->email        = md5($user->username);// Store hash of username, useful importing/restoring users
    $updateuser->idnumber     = '';                  // Clear this field to free it up
    $updateuser->timemodified = time();

    $DB->update_record('user', $updateuser);

    // We will update the user's timemodified, as it will be passed to the user_deleted event, which
    // should know about this updated property persisted to the user's table.
    $user->timemodified = $updateuser->timemodified;

    // notify auth plugin - do not block the delete even when plugin fails
    $authplugin = get_auth_plugin($user->auth);
    $authplugin->user_delete($user);

    // any plugin that needs to cleanup should register this event
    events_trigger('user_deleted', $user);

    return true;
}

function guest_user() {
    global $CFG, $DB;

    if ($newuser = $DB->get_record('user', array('id'=>$CFG->siteguest))) {
        $newuser->confirmed = 1;
        $newuser->lang = $CFG->lang;
        $newuser->lastip = getremoteaddr();
    }

    return $newuser;
}

function authenticate_user_login($username, $password) {
    global $CFG, $DB;

    $authsenabled = get_enabled_auth_plugins();

    if ($user = get_complete_user_data('username', $username, $CFG->mnet_localhost_id)) {
        $auth = empty($user->auth) ? 'manual' : $user->auth;  // use manual if auth not set
        if (!empty($user->suspended)) {
            add_to_log(SITEID, 'login', 'error', 'index.php', $username);
            error_log('[client '.getremoteaddr()."]  $CFG->wwwroot  Suspended Login:  $username  ".$_SERVER['HTTP_USER_AGENT']);
            return false;
        }
        if ($auth=='nologin' or !is_enabled_auth($auth)) {
            add_to_log(SITEID, 'login', 'error', 'index.php', $username);
            error_log('[client '.getremoteaddr()."]  $CFG->wwwroot  Disabled Login:  $username  ".$_SERVER['HTTP_USER_AGENT']);
            return false;
        }
        $auths = array($auth);

    } else {
        // check if there's a deleted record (cheaply)
        if ($DB->get_field('user', 'id', array('username'=>$username, 'deleted'=>1))) {
            error_log('[client '.getremoteaddr()."]  $CFG->wwwroot  Deleted Login:  $username  ".$_SERVER['HTTP_USER_AGENT']);
            return false;
        }

        // User does not exist
        $auths = $authsenabled;
        $user = new stdClass();
        $user->id = 0;
    }

    foreach ($auths as $auth) {
        $authplugin = get_auth_plugin($auth);

        // on auth fail fall through to the next plugin
        if (!$authplugin->user_login($username, $password)) {
            continue;
        }

        // successful authentication
        if ($user->id) {                          // User already exists in database
            if (empty($user->auth)) {             // For some reason auth isn't set yet
                $DB->set_field('user', 'auth', $auth, array('username'=>$username));
                $user->auth = $auth;
            }
            if (empty($user->firstaccess)) { //prevent firstaccess from remaining 0 for manual account that never required confirmation
                $DB->set_field('user','firstaccess', $user->timemodified, array('id' => $user->id));
                $user->firstaccess = $user->timemodified;
            }

            update_internal_user_password($user, $password); // just in case salt or encoding were changed (magic quotes too one day)

            if ($authplugin->is_synchronised_with_external()) { // update user record from external DB
                $user = update_user_record($username);
            }
        } else {
            // if user not found and user creation is not disabled, create it
            if (empty($CFG->authpreventaccountcreation)) {
                $user = create_user_record($username, $password, $auth);
            } else {
                continue;
            }
        }

        $authplugin->sync_roles($user);

        foreach ($authsenabled as $hau) {
            $hauth = get_auth_plugin($hau);
            $hauth->user_authenticated_hook($user, $username, $password);
        }

        if (empty($user->id)) {
            return false;
        }

        if (!empty($user->suspended)) {
            // just in case some auth plugin suspended account
            add_to_log(SITEID, 'login', 'error', 'index.php', $username);
            error_log('[client '.getremoteaddr()."]  $CFG->wwwroot  Suspended Login:  $username  ".$_SERVER['HTTP_USER_AGENT']);
            return false;
        }

        return $user;
    }

    // failed if all the plugins have failed
    add_to_log(SITEID, 'login', 'error', 'index.php', $username);
    if (debugging('', DEBUG_ALL)) {
        error_log('[client '.getremoteaddr()."]  $CFG->wwwroot  Failed Login:  $username  ".$_SERVER['HTTP_USER_AGENT']);
    }
    return false;
}

function complete_user_login($user) {
    global $CFG, $USER;

    // regenerate session id and delete old session,
    // this helps prevent session fixation attacks from the same domain
    session_regenerate_id(true);

    // let enrol plugins deal with new enrolments if necessary
    enrol_check_plugins($user);

    // check enrolments, load caps and setup $USER object
    session_set_user($user);

    // reload preferences from DB
    unset($USER->preference);
    check_user_preferences_loaded($USER);

    // update login times
    update_user_login_times();

    // extra session prefs init
    set_login_session_preferences();

    if (isguestuser()) {
        // no need to continue when user is THE guest
        return $USER;
    }

    $userauth = get_auth_plugin($USER->auth);

    if (get_user_preferences('auth_forcepasswordchange', false)){
        if ($userauth->can_change_password()) {
            if ($changeurl = $userauth->change_password_url()) {
                redirect($changeurl);
            } else {
                redirect($CFG->httpswwwroot.'/login/change_password.php');
            }
        } else {
            print_error('nopasswordchangeforced', 'auth');
        }
    }
    return $USER;
}

function validate_internal_user_password($user, $password) {
    global $CFG;

    if (!isset($CFG->passwordsaltmain)) {
        $CFG->passwordsaltmain = '';
    }

    $validated = false;

    if ($user->password === 'not cached') {
        // internal password is not used at all, it can not validate

    } else if ($user->password === md5($password.$CFG->passwordsaltmain)
            or $user->password === md5($password)
            or $user->password === md5(addslashes($password).$CFG->passwordsaltmain)
            or $user->password === md5(addslashes($password))) {
        // note: we are intentionally using the addslashes() here because we
        //       need to accept old password hashes of passwords with magic quotes
        $validated = true;

    } else {
        for ($i=1; $i<=20; $i++) { //20 alternative salts should be enough, right?
            $alt = 'passwordsaltalt'.$i;
            if (!empty($CFG->$alt)) {
                if ($user->password === md5($password.$CFG->$alt) or $user->password === md5(addslashes($password).$CFG->$alt)) {
                    $validated = true;
                    break;
                }
            }
        }
    }

    if ($validated) {
        // force update of password hash using latest main password salt and encoding if needed
        update_internal_user_password($user, $password);
    }

    return $validated;
}

function hash_internal_user_password($password) {
    global $CFG;

    if (isset($CFG->passwordsaltmain)) {
        return md5($password.$CFG->passwordsaltmain);
    } else {
        return md5($password);
    }
}

function update_internal_user_password($user, $password) {
    global $DB;

    $authplugin = get_auth_plugin($user->auth);
    if ($authplugin->prevent_local_passwords()) {
        $hashedpassword = 'not cached';
    } else {
        $hashedpassword = hash_internal_user_password($password);
    }

    if ($user->password !== $hashedpassword) {
        $DB->set_field('user', 'password',  $hashedpassword, array('id'=>$user->id));
        $user->password = $hashedpassword;
    }

    return true;
}

function get_complete_user_data($field, $value, $mnethostid = null) {
    global $CFG, $DB;

    if (!$field || !$value) {
        return false;
    }

    $params = array('fieldval'=>$value);
    $constraints = "$field = :fieldval AND deleted <> 1";

    // If we are loading user data based on anything other than id,
    // we must also restrict our search based on mnet host.
    if ($field != 'id') {
        if (empty($mnethostid)) {
            // if empty, we restrict to local users
            $mnethostid = $CFG->mnet_localhost_id;
        }
    }
    if (!empty($mnethostid)) {
        $params['mnethostid'] = $mnethostid;
        $constraints .= " AND mnethostid = :mnethostid";
    }


    if (! $user = $DB->get_record_select('user', $constraints, $params)) {
        return false;
    }


    // preload preference cache
    check_user_preferences_loaded($user);

    // load course enrolment related stuff
    $user->lastcourseaccess    = array(); // during last session
    $user->currentcourseaccess = array(); // during current session
    if ($lastaccesses = $DB->get_records('user_lastaccess', array('userid'=>$user->id))) {
        foreach ($lastaccesses as $lastaccess) {
            $user->lastcourseaccess[$lastaccess->courseid] = $lastaccess->timeaccess;
        }
    }

    $sql = "SELECT g.id, g.courseid
              FROM {groups} g, {groups_members} gm
             WHERE gm.groupid=g.id AND gm.userid=?";

    // this is a special hack to speedup calendar display
    $user->groupmember = array();
    if (!isguestuser($user)) {
        if ($groups = $DB->get_records_sql($sql, array($user->id))) {
            foreach ($groups as $group) {
                if (!array_key_exists($group->courseid, $user->groupmember)) {
                    $user->groupmember[$group->courseid] = array();
                }
                $user->groupmember[$group->courseid][$group->id] = $group->id;
            }
        }
    }

    $user->profile = array();
    if (!isguestuser($user)) {
        require_once($CFG->dirroot.'/user/profile/lib.php');
        profile_load_custom_fields($user);
    }

    if (!empty($user->description)) {
        $user->description = true;   // No need to cart all of it around
    }
    if (isguestuser($user)) {
        $user->lang       = $CFG->lang;               // Guest language always same as site
        $user->firstname  = get_string('guestuser');  // Name always in current language
        $user->lastname   = ' ';
    }

    return $user;
}

function check_password_policy($password, &$errmsg) {
    global $CFG;

    if (empty($CFG->passwordpolicy)) {
        return true;
    }

    $textlib = textlib_get_instance();
    $errmsg = '';
    if ($textlib->strlen($password) < $CFG->minpasswordlength) {
        $errmsg .= '<div>'. get_string('errorminpasswordlength', 'auth', $CFG->minpasswordlength) .'</div>';

    }
    if (preg_match_all('/[[:digit:]]/u', $password, $matches) < $CFG->minpassworddigits) {
        $errmsg .= '<div>'. get_string('errorminpassworddigits', 'auth', $CFG->minpassworddigits) .'</div>';

    }
    if (preg_match_all('/[[:lower:]]/u', $password, $matches) < $CFG->minpasswordlower) {
        $errmsg .= '<div>'. get_string('errorminpasswordlower', 'auth', $CFG->minpasswordlower) .'</div>';

    }
    if (preg_match_all('/[[:upper:]]/u', $password, $matches) < $CFG->minpasswordupper) {
        $errmsg .= '<div>'. get_string('errorminpasswordupper', 'auth', $CFG->minpasswordupper) .'</div>';

    }
    if (preg_match_all('/[^[:upper:][:lower:][:digit:]]/u', $password, $matches) < $CFG->minpasswordnonalphanum) {
        $errmsg .= '<div>'. get_string('errorminpasswordnonalphanum', 'auth', $CFG->minpasswordnonalphanum) .'</div>';
    }
    if (!check_consecutive_identical_characters($password, $CFG->maxconsecutiveidentchars)) {
        $errmsg .= '<div>'. get_string('errormaxconsecutiveidentchars', 'auth', $CFG->maxconsecutiveidentchars) .'</div>';
    }

    if ($errmsg == '') {
        return true;
    } else {
        return false;
    }
}


function set_login_session_preferences() {
    global $SESSION, $CFG;

    $SESSION->justloggedin = true;

    unset($SESSION->lang);
}


function delete_course($courseorid, $showfeedback = true) {
    global $DB;

    if (is_object($courseorid)) {
        $courseid = $courseorid->id;
        $course   = $courseorid;
    } else {
        $courseid = $courseorid;
        if (!$course = $DB->get_record('course', array('id'=>$courseid))) {
            return false;
        }
    }
    $context = get_context_instance(CONTEXT_COURSE, $courseid);

    // frontpage course can not be deleted!!
    if ($courseid == SITEID) {
        return false;
    }

    // make the course completely empty
    remove_course_contents($courseid, $showfeedback);

    // delete the course and related context instance
    delete_context(CONTEXT_COURSE, $courseid);

    // We will update the course's timemodified, as it will be passed to the course_deleted event,
    // which should know about this updated property, as this event is meant to pass the full course record
    $course->timemodified = time();

    $DB->delete_records("course", array("id"=>$courseid));

    //trigger events
    $course->context = $context; // you can not fetch context in the event because it was already deleted
    events_trigger('course_deleted', $course);

    return true;
}

function remove_course_contents($courseid, $showfeedback = true, array $options = null) {
    global $CFG, $DB, $OUTPUT;
    require_once($CFG->libdir.'/completionlib.php');
    require_once($CFG->libdir.'/questionlib.php');
    require_once($CFG->libdir.'/gradelib.php');
    require_once($CFG->dirroot.'/group/lib.php');
    require_once($CFG->dirroot.'/tag/coursetagslib.php');
    require_once($CFG->dirroot.'/comment/lib.php');
    require_once($CFG->dirroot.'/rating/lib.php');

    // NOTE: these concatenated strings are suboptimal, but it is just extra info...
    $strdeleted = get_string('deleted').' - ';

    // Some crazy wishlist of stuff we should skip during purging of course content
    $options = (array)$options;

    $course = $DB->get_record('course', array('id'=>$courseid), '*', MUST_EXIST);
    $coursecontext = context_course::instance($courseid);
    $fs = get_file_storage();

    // Delete course completion information, this has to be done before grades and enrols
    $cc = new completion_info($course);
    $cc->clear_criteria();
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted.get_string('completion', 'completion'), 'notifysuccess');
    }

    // Remove all data from gradebook - this needs to be done before course modules
    // because while deleting this information, the system may need to reference
    // the course modules that own the grades.
    remove_course_grades($courseid, $showfeedback);
    remove_grade_letters($coursecontext, $showfeedback);

    // Delete course blocks in any all child contexts,
    // they may depend on modules so delete them first
    $childcontexts = $coursecontext->get_child_contexts(); // returns all subcontexts since 2.2
    foreach ($childcontexts as $childcontext) {
        blocks_delete_all_for_context($childcontext->id);
    }
    unset($childcontexts);
    blocks_delete_all_for_context($coursecontext->id);
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted.get_string('type_block_plural', 'plugin'), 'notifysuccess');
    }

    // Delete every instance of every module,
    // this has to be done before deleting of course level stuff
    $locations = get_plugin_list('mod');
    foreach ($locations as $modname=>$moddir) {
        if ($modname === 'NEWMODULE') {
            continue;
        }
        if ($module = $DB->get_record('modules', array('name'=>$modname))) {
            include_once("$moddir/lib.php");                 // Shows php warning only if plugin defective
            $moddelete = $modname .'_delete_instance';       // Delete everything connected to an instance
            $moddeletecourse = $modname .'_delete_course';   // Delete other stray stuff (uncommon)

            if ($instances = $DB->get_records($modname, array('course'=>$course->id))) {
                foreach ($instances as $instance) {
                    if ($cm = get_coursemodule_from_instance($modname, $instance->id, $course->id)) {
                        question_delete_activity($cm,  $showfeedback);
                    }
                    if (function_exists($moddelete)) {
                        // This purges all module data in related tables, extra user prefs, settings, etc.
                        $moddelete($instance->id);
                    } else {
                        // NOTE: we should not allow installation of modules with missing delete support!
                        debugging("Defective module '$modname' detected when deleting course contents: missing function $moddelete()!");
                        $DB->delete_records($modname, array('id'=>$instance->id));
                    }

                    if ($cm) {
                        // Delete cm and its context - orphaned contexts are purged in cron in case of any race condition
                        context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
                        $DB->delete_records('course_modules', array('id'=>$cm->id));
                    }
                }
            }
            if (function_exists($moddeletecourse)) {
                // Execute ptional course cleanup callback
                $moddeletecourse($course, $showfeedback);
            }
            if ($instances and $showfeedback) {
                echo $OUTPUT->notification($strdeleted.get_string('pluginname', $modname), 'notifysuccess');
            }
        } else {
            // Ooops, this module is not properly installed, force-delete it in the next block
        }
    }
    // We have tried to delete everything the nice way - now let's force-delete any remaining module data
    $cms = $DB->get_records('course_modules', array('course'=>$course->id));
    foreach ($cms as $cm) {
        if ($module = $DB->get_record('modules', array('id'=>$cm->module))) {
            try {
                $DB->delete_records($module->name, array('id'=>$cm->instance));
            } catch (Exception $e) {
                // Ignore weird or missing table problems
            }
        }
        context_helper::delete_instance(CONTEXT_MODULE, $cm->id);
        $DB->delete_records('course_modules', array('id'=>$cm->id));
    }
    // Remove all data from availability and completion tables that is associated
    // with course-modules belonging to this course. Note this is done even if the
    // features are not enabled now, in case they were enabled previously
    $DB->delete_records_select('course_modules_completion',
           'coursemoduleid IN (SELECT id from {course_modules} WHERE course=?)',
           array($courseid));
    $DB->delete_records_select('course_modules_availability',
           'coursemoduleid IN (SELECT id from {course_modules} WHERE course=?)',
           array($courseid));
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted.get_string('type_mod_plural', 'plugin'), 'notifysuccess');
    }

    // Cleanup the rest of plugins
    $cleanuplugintypes = array('report', 'coursereport', 'format');
    foreach ($cleanuplugintypes as $type) {
        $plugins = get_plugin_list_with_function($type, 'delete_course', 'lib.php');
        foreach ($plugins as $plugin=>$pluginfunction) {
            $pluginfunction($course->id, $showfeedback);
        }
        if ($showfeedback) {
            echo $OUTPUT->notification($strdeleted.get_string('type_'.$type.'_plural', 'plugin'), 'notifysuccess');
        }
    }

    // Delete questions and question categories
    question_delete_course($course, $showfeedback);
    if ($showfeedback) {
        echo $OUTPUT->notification($strdeleted.get_string('questions', 'question'), 'notifysuccess');
    }

    // Make sure there are no subcontexts left - all valid blocks and modules should be already gone
    $childcontexts = $coursecontext->get_child_contexts(); // returns all subcontexts since 2.2
    foreach ($childcontexts as $childcontext) {
        $childcontext->delete();
    }
    unset($childcontexts);

    // Remove all roles and enrolments by default
    if (empty($options['keep_roles_and_enrolments'])) {
        // this hack is used in restore when deleting contents of existing course
        role_unassign_all(array('contextid'=>$coursecontext->id), true);
        enrol_course_delete($course);
        if ($showfeedback) {
            echo $OUTPUT->notification($strdeleted.get_string('type_enrol_plural', 'plugin'), 'notifysuccess');
        }
    }

    // Delete any groups, removing members and grouping/course links first.
    if (empty($options['keep_groups_and_groupings'])) {
        groups_delete_groupings($course->id, $showfeedback);
        groups_delete_groups($course->id, $showfeedback);
    }

    // filters be gone!
    filter_delete_all_for_context($coursecontext->id);

    // die comments!
    comment::delete_comments($coursecontext->id);

    // ratings are history too
    $delopt = new stdclass();
    $delopt->contextid = $coursecontext->id;
    $rm = new rating_manager();
    $rm->delete_ratings($delopt);

    // Delete course tags
    coursetag_delete_course_tags($course->id, $showfeedback);

    // Delete calendar events
    $DB->delete_records('event', array('courseid'=>$course->id));
    $fs->delete_area_files($coursecontext->id, 'calendar');

    // Delete all related records in other core tables that may have a courseid
    // This array stores the tables that need to be cleared, as
    // table_name => column_name that contains the course id.
    $tablestoclear = array(
        'log' => 'course',               // Course logs (NOTE: this might be changed in the future)
        'backup_courses' => 'courseid',  // Scheduled backup stuff
        'user_lastaccess' => 'courseid', // User access info
    );
    foreach ($tablestoclear as $table => $col) {
        $DB->delete_records($table, array($col=>$course->id));
    }

    // delete all course backup files
    $fs->delete_area_files($coursecontext->id, 'backup');

    // cleanup course record - remove links to deleted stuff
    $oldcourse = new stdClass();
    $oldcourse->id               = $course->id;
    $oldcourse->summary          = '';
    $oldcourse->modinfo          = NULL;
    $oldcourse->legacyfiles      = 0;
    $oldcourse->enablecompletion = 0;
    if (!empty($options['keep_groups_and_groupings'])) {
        $oldcourse->defaultgroupingid = 0;
    }
    $DB->update_record('course', $oldcourse);

    // Delete course sections and user selections
    $DB->delete_records('course_sections', array('course'=>$course->id));
    $DB->delete_records('course_display', array('course'=>$course->id));

    // delete legacy, section and any other course files
    $fs->delete_area_files($coursecontext->id, 'course'); // files from summary and section

    // Delete all remaining stuff linked to context such as files, comments, ratings, etc.
    if (empty($options['keep_roles_and_enrolments']) and empty($options['keep_groups_and_groupings'])) {
        // Easy, do not delete the context itself...
        $coursecontext->delete_content();

    } else {
        // Hack alert!!!!
        // We can not drop all context stuff because it would bork enrolments and roles,
        // there might be also files used by enrol plugins...
    }

    // Delete legacy files - just in case some files are still left there after conversion to new file api,
    // also some non-standard unsupported plugins may try to store something there
    fulldelete($CFG->dataroot.'/'.$course->id);

    // Finally trigger the event
    $course->context = $coursecontext; // you can not access context in cron event later after course is deleted
    $course->options = $options;       // not empty if we used any crazy hack
    events_trigger('course_content_removed', $course);

    return true;
}

function shift_course_mod_dates($modname, $fields, $timeshift, $courseid) {
    global $CFG, $DB;
    include_once($CFG->dirroot.'/mod/'.$modname.'/lib.php');

    $return = true;
    foreach ($fields as $field) {
        $updatesql = "UPDATE {".$modname."}
                          SET $field = $field + ?
                        WHERE course=? AND $field<>0 AND $field<>0";
        $return = $DB->execute($updatesql, array($timeshift, $courseid)) && $return;
    }

    $refreshfunction = $modname.'_refresh_events';
    if (function_exists($refreshfunction)) {
        $refreshfunction($courseid);
    }

    return $return;
}

function reset_course_userdata($data) {
    global $CFG, $USER, $DB;
    require_once($CFG->libdir.'/gradelib.php');
    require_once($CFG->libdir.'/completionlib.php');
    require_once($CFG->dirroot.'/group/lib.php');

    $data->courseid = $data->id;
    $context = get_context_instance(CONTEXT_COURSE, $data->courseid);

    // calculate the time shift of dates
    if (!empty($data->reset_start_date)) {
        // time part of course startdate should be zero
        $data->timeshift = $data->reset_start_date - usergetmidnight($data->reset_start_date_old);
    } else {
        $data->timeshift = 0;
    }

    // result array: component, item, error
    $status = array();

    // start the resetting
    $componentstr = get_string('general');

    // move the course start time
    if (!empty($data->reset_start_date) and $data->timeshift) {
        // change course start data
        $DB->set_field('course', 'startdate', $data->reset_start_date, array('id'=>$data->courseid));
        // update all course and group events - do not move activity events
        $updatesql = "UPDATE {event}
                         SET timestart = timestart + ?
                       WHERE courseid=? AND instance=0";
        $DB->execute($updatesql, array($data->timeshift, $data->courseid));

        $status[] = array('component'=>$componentstr, 'item'=>get_string('datechanged'), 'error'=>false);
    }

    if (!empty($data->reset_logs)) {
        $DB->delete_records('log', array('course'=>$data->courseid));
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deletelogs'), 'error'=>false);
    }

    if (!empty($data->reset_events)) {
        $DB->delete_records('event', array('courseid'=>$data->courseid));
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deleteevents', 'calendar'), 'error'=>false);
    }

    if (!empty($data->reset_notes)) {
        require_once($CFG->dirroot.'/notes/lib.php');
        note_delete_all($data->courseid);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deletenotes', 'notes'), 'error'=>false);
    }

    if (!empty($data->delete_blog_associations)) {
        require_once($CFG->dirroot.'/blog/lib.php');
        blog_remove_associations_for_course($data->courseid);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deleteblogassociations', 'blog'), 'error'=>false);
    }

    if (!empty($data->reset_course_completion)) {
        // Delete course completion information
        $course = $DB->get_record('course', array('id'=>$data->courseid));
        $cc = new completion_info($course);
        $cc->delete_course_completion_data();
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deletecoursecompletiondata', 'completion'), 'error'=>false);
    }

    $componentstr = get_string('roles');

    if (!empty($data->reset_roles_overrides)) {
        $children = get_child_contexts($context);
        foreach ($children as $child) {
            $DB->delete_records('role_capabilities', array('contextid'=>$child->id));
        }
        $DB->delete_records('role_capabilities', array('contextid'=>$context->id));
        //force refresh for logged in users
        mark_context_dirty($context->path);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deletecourseoverrides', 'role'), 'error'=>false);
    }

    if (!empty($data->reset_roles_local)) {
        $children = get_child_contexts($context);
        foreach ($children as $child) {
            role_unassign_all(array('contextid'=>$child->id));
        }
        //force refresh for logged in users
        mark_context_dirty($context->path);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deletelocalroles', 'role'), 'error'=>false);
    }

    // First unenrol users - this cleans some of related user data too, such as forum subscriptions, tracking, etc.
    $data->unenrolled = array();
    if (!empty($data->unenrol_users)) {
        $plugins = enrol_get_plugins(true);
        $instances = enrol_get_instances($data->courseid, true);
        foreach ($instances as $key=>$instance) {
            if (!isset($plugins[$instance->enrol])) {
                unset($instances[$key]);
                continue;
            }
            if (!$plugins[$instance->enrol]->allow_unenrol($instance)) {
                unset($instances[$key]);
            }
        }

        $sqlempty = $DB->sql_empty();
        foreach($data->unenrol_users as $withroleid) {
            $sql = "SELECT DISTINCT ue.userid, ue.enrolid
                      FROM {user_enrolments} ue
                      JOIN {enrol} e ON (e.id = ue.enrolid AND e.courseid = :courseid)
                      JOIN {context} c ON (c.contextlevel = :courselevel AND c.instanceid = e.courseid)
                      JOIN {role_assignments} ra ON (ra.contextid = c.id AND ra.roleid = :roleid AND ra.userid = ue.userid)";
            $params = array('courseid'=>$data->courseid, 'roleid'=>$withroleid, 'courselevel'=>CONTEXT_COURSE);

            $rs = $DB->get_recordset_sql($sql, $params);
            foreach ($rs as $ue) {
                if (!isset($instances[$ue->enrolid])) {
                    continue;
                }
                $plugins[$instances[$ue->enrolid]->enrol]->unenrol_user($instances[$ue->enrolid], $ue->userid);
                $data->unenrolled[$ue->userid] = $ue->userid;
            }
        }
    }
    if (!empty($data->unenrolled)) {
        $status[] = array('component'=>$componentstr, 'item'=>get_string('unenrol', 'enrol').' ('.count($data->unenrolled).')', 'error'=>false);
    }


    $componentstr = get_string('groups');

    // remove all group members
    if (!empty($data->reset_groups_members)) {
        groups_delete_group_members($data->courseid);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('removegroupsmembers', 'group'), 'error'=>false);
    }

    // remove all groups
    if (!empty($data->reset_groups_remove)) {
        groups_delete_groups($data->courseid, false);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deleteallgroups', 'group'), 'error'=>false);
    }

    // remove all grouping members
    if (!empty($data->reset_groupings_members)) {
        groups_delete_groupings_groups($data->courseid, false);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('removegroupingsmembers', 'group'), 'error'=>false);
    }

    // remove all groupings
    if (!empty($data->reset_groupings_remove)) {
        groups_delete_groupings($data->courseid, false);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('deleteallgroupings', 'group'), 'error'=>false);
    }

    // Look in every instance of every module for data to delete
    $unsupported_mods = array();
    if ($allmods = $DB->get_records('modules') ) {
        foreach ($allmods as $mod) {
            $modname = $mod->name;
            if (!$DB->count_records($modname, array('course'=>$data->courseid))) {
                continue; // skip mods with no instances
            }
            $modfile = $CFG->dirroot.'/mod/'. $modname.'/lib.php';
            $moddeleteuserdata = $modname.'_reset_userdata';   // Function to delete user data
            if (file_exists($modfile)) {
                include_once($modfile);
                if (function_exists($moddeleteuserdata)) {
                    $modstatus = $moddeleteuserdata($data);
                    if (is_array($modstatus)) {
                        $status = array_merge($status, $modstatus);
                    } else {
                        debugging('Module '.$modname.' returned incorrect staus - must be an array!');
                    }
                } else {
                    $unsupported_mods[] = $mod;
                }
            } else {
                debugging('Missing lib.php in '.$modname.' module!');
            }
        }
    }

    // mention unsupported mods
    if (!empty($unsupported_mods)) {
        foreach($unsupported_mods as $mod) {
            $status[] = array('component'=>get_string('modulenameplural', $mod->name), 'item'=>'', 'error'=>get_string('resetnotimplemented'));
        }
    }


    $componentstr = get_string('gradebook', 'grades');
    // reset gradebook
    if (!empty($data->reset_gradebook_items)) {
        remove_course_grades($data->courseid, false);
        grade_grab_course_grades($data->courseid);
        grade_regrade_final_grades($data->courseid);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('removeallcourseitems', 'grades'), 'error'=>false);

    } else if (!empty($data->reset_gradebook_grades)) {
        grade_course_reset($data->courseid);
        $status[] = array('component'=>$componentstr, 'item'=>get_string('removeallcoursegrades', 'grades'), 'error'=>false);
    }
    // reset comments
    if (!empty($data->reset_comments)) {
        require_once($CFG->dirroot.'/comment/lib.php');
        comment::reset_course_page_comments($context);
    }

    return $status;
}

function generate_email_processing_address($modid,$modargs) {
    global $CFG;

    $header = $CFG->mailprefix . substr(base64_encode(pack('C',$modid)),0,2).$modargs;
    return $header . substr(md5($header.get_site_identifier()),0,16).'@'.$CFG->maildomain;
}

function moodle_process_email($modargs,$body) {
    global $DB;

    // the first char should be an unencoded letter. We'll take this as an action
    switch ($modargs{0}) {
        case 'B': { // bounce
            list(,$userid) = unpack('V',base64_decode(substr($modargs,1,8)));
            if ($user = $DB->get_record("user", array('id'=>$userid), "id,email")) {
                // check the half md5 of their email
                $md5check = substr(md5($user->email),0,16);
                if ($md5check == substr($modargs, -16)) {
                    set_bounce_count($user);
                }
                // else maybe they've already changed it?
            }
        }
        break;
        // maybe more later?
    }
}


function get_mailer($action='get') {
    global $CFG;

    static $mailer  = null;
    static $counter = 0;

    if (!isset($CFG->smtpmaxbulk)) {
        $CFG->smtpmaxbulk = 1;
    }

    if ($action == 'get') {
        $prevkeepalive = false;

        if (isset($mailer) and $mailer->Mailer == 'smtp') {
            if ($counter < $CFG->smtpmaxbulk and !$mailer->IsError()) {
                $counter++;
                // reset the mailer
                $mailer->Priority         = 3;
                $mailer->CharSet          = 'UTF-8'; // our default
                $mailer->ContentType      = "text/plain";
                $mailer->Encoding         = "8bit";
                $mailer->From             = "root@localhost";
                $mailer->FromName         = "Root User";
                $mailer->Sender           = "";
                $mailer->Subject          = "";
                $mailer->Body             = "";
                $mailer->AltBody          = "";
                $mailer->ConfirmReadingTo = "";

                $mailer->ClearAllRecipients();
                $mailer->ClearReplyTos();
                $mailer->ClearAttachments();
                $mailer->ClearCustomHeaders();
                return $mailer;
            }

            $prevkeepalive = $mailer->SMTPKeepAlive;
            get_mailer('flush');
        }

        include_once($CFG->libdir.'/phpmailer/moodle_phpmailer.php');
        $mailer = new moodle_phpmailer();

        $counter = 1;

        $mailer->Version   = 'Moodle '.$CFG->version;         // mailer version
        $mailer->PluginDir = $CFG->libdir.'/phpmailer/';      // plugin directory (eg smtp plugin)
        $mailer->CharSet   = 'UTF-8';

        // some MTAs may do double conversion of LF if CRLF used, CRLF is required line ending in RFC 822bis
        if (isset($CFG->mailnewline) and $CFG->mailnewline == 'CRLF') {
            $mailer->LE = "\r\n";
        } else {
            $mailer->LE = "\n";
        }

        if ($CFG->smtphosts == 'qmail') {
            $mailer->IsQmail();                              // use Qmail system

        } else if (empty($CFG->smtphosts)) {
            $mailer->IsMail();                               // use PHP mail() = sendmail

        } else {
            $mailer->IsSMTP();                               // use SMTP directly
            if (!empty($CFG->debugsmtp)) {
                $mailer->SMTPDebug = true;
            }
            $mailer->Host          = $CFG->smtphosts;        // specify main and backup servers
            $mailer->SMTPKeepAlive = $prevkeepalive;         // use previous keepalive

            if ($CFG->smtpuser) {                            // Use SMTP authentication
                $mailer->SMTPAuth = true;
                $mailer->Username = $CFG->smtpuser;
                $mailer->Password = $CFG->smtppass;
            }
        }

        return $mailer;
    }

    $nothing = null;

    // keep smtp session open after sending
    if ($action == 'buffer') {
        if (!empty($CFG->smtpmaxbulk)) {
            get_mailer('flush');
            $m = get_mailer();
            if ($m->Mailer == 'smtp') {
                $m->SMTPKeepAlive = true;
            }
        }
        return $nothing;
    }

    // close smtp session, but continue buffering
    if ($action == 'flush') {
        if (isset($mailer) and $mailer->Mailer == 'smtp') {
            if (!empty($mailer->SMTPDebug)) {
                echo '<pre>'."\n";
            }
            $mailer->SmtpClose();
            if (!empty($mailer->SMTPDebug)) {
                echo '</pre>';
            }
        }
        return $nothing;
    }

    // close smtp session, do not buffer anymore
    if ($action == 'close') {
        if (isset($mailer) and $mailer->Mailer == 'smtp') {
            get_mailer('flush');
            $mailer->SMTPKeepAlive = false;
        }
        $mailer = null; // better force new instance
        return $nothing;
    }
}

function email_to_user($user, $from, $subject, $messagetext, $messagehtml='', $attachment='', $attachname='', $usetrueaddress=true, $replyto='', $replytoname='', $wordwrapwidth=79) {

    global $CFG, $FULLME;

    if (empty($user) || empty($user->email)) {
        mtrace('Error: lib/moodlelib.php email_to_user(): User is null or has no email');
        return false;
    }

    if (!empty($user->deleted)) {
        // do not mail delted users
        mtrace('Error: lib/moodlelib.php email_to_user(): User is deleted');
        return false;
    }

    if (!empty($CFG->noemailever)) {
        // hidden setting for development sites, set in config.php if needed
        mtrace('Error: lib/moodlelib.php email_to_user(): Not sending email due to noemailever config setting');
        return true;
    }

    if (!empty($CFG->divertallemailsto)) {
        $subject = "[DIVERTED {$user->email}] $subject";
        $user = clone($user);
        $user->email = $CFG->divertallemailsto;
    }

    // skip mail to suspended users
    if ((isset($user->auth) && $user->auth=='nologin') or (isset($user->suspended) && $user->suspended)) {
        return true;
    }

    if (!validate_email($user->email)) {
        // we can not send emails to invalid addresses - it might create security issue or confuse the mailer
        $invalidemail = "User $user->id (".fullname($user).") email ($user->email) is invalid! Not sending.";
        error_log($invalidemail);
        if (CLI_SCRIPT) {
            // do not print this in standard web pages
            mtrace($invalidemail);
        }
        return false;
    }

    if (over_bounce_threshold($user)) {
        $bouncemsg = "User $user->id (".fullname($user).") is over bounce threshold! Not sending.";
        error_log($bouncemsg);
        mtrace('Error: lib/moodlelib.php email_to_user(): '.$bouncemsg);
        return false;
    }

    // If the user is a remote mnet user, parse the email text for URL to the
    // wwwroot and modify the url to direct the user's browser to login at their
    // home site (identity provider - idp) before hitting the link itself
    if (is_mnet_remote_user($user)) {
        require_once($CFG->dirroot.'/mnet/lib.php');

        $jumpurl = mnet_get_idp_jump_url($user);
        $callback = partial('mnet_sso_apply_indirection', $jumpurl);

        $messagetext = preg_replace_callback("%($CFG->wwwroot[^[:space:]]*)%",
                $callback,
                $messagetext);
        $messagehtml = preg_replace_callback("%href=[\"'`]($CFG->wwwroot[\w_:\?=#&@/;.~-]*)[\"'`]%",
                $callback,
                $messagehtml);
    }
    $mail = get_mailer();

    if (!empty($mail->SMTPDebug)) {
        echo '<pre>' . "\n";
    }

    $temprecipients = array();
    $tempreplyto = array();

    $supportuser = generate_email_supportuser();

    // make up an email address for handling bounces
    if (!empty($CFG->handlebounces)) {
        $modargs = 'B'.base64_encode(pack('V',$user->id)).substr(md5($user->email),0,16);
        $mail->Sender = generate_email_processing_address(0,$modargs);
    } else {
        $mail->Sender = $supportuser->email;
    }

    if (is_string($from)) { // So we can pass whatever we want if there is need
        $mail->From     = $CFG->noreplyaddress;
        $mail->FromName = $from;
    } else if ($usetrueaddress and $from->maildisplay) {
        $mail->From     = $from->email;
        $mail->FromName = fullname($from);
    } else {
        $mail->From     = $CFG->noreplyaddress;
        $mail->FromName = fullname($from);
        if (empty($replyto)) {
            $tempreplyto[] = array($CFG->noreplyaddress, get_string('noreplyname'));
        }
    }

    if (!empty($replyto)) {
        $tempreplyto[] = array($replyto, $replytoname);
    }

    $mail->Subject = substr($subject, 0, 900);

    $temprecipients[] = array($user->email, fullname($user));

    $mail->WordWrap = $wordwrapwidth;                   // set word wrap

    if (!empty($from->customheaders)) {                 // Add custom headers
        if (is_array($from->customheaders)) {
            foreach ($from->customheaders as $customheader) {
                $mail->AddCustomHeader($customheader);
            }
        } else {
            $mail->AddCustomHeader($from->customheaders);
        }
    }

    if (!empty($from->priority)) {
        $mail->Priority = $from->priority;
    }

    if ($messagehtml && !empty($user->mailformat) && $user->mailformat == 1) { // Don't ever send HTML to users who don't want it
        $mail->IsHTML(true);
        $mail->Encoding = 'quoted-printable';           // Encoding to use
        $mail->Body    =  $messagehtml;
        $mail->AltBody =  "\n$messagetext\n";
    } else {
        $mail->IsHTML(false);
        $mail->Body =  "\n$messagetext\n";
    }

    if ($attachment && $attachname) {
        if (preg_match( "~\\.\\.~" ,$attachment )) {    // Security check for ".." in dir path
            $temprecipients[] = array($supportuser->email, fullname($supportuser, true));
            $mail->AddStringAttachment('Error in attachment.  User attempted to attach a filename with a unsafe name.', 'error.txt', '8bit', 'text/plain');
        } else {
            require_once($CFG->libdir.'/filelib.php');
            $mimetype = mimeinfo('type', $attachname);
            $mail->AddAttachment($CFG->dataroot .'/'. $attachment, $attachname, 'base64', $mimetype);
        }
    }

    // Check if the email should be sent in an other charset then the default UTF-8
    if ((!empty($CFG->sitemailcharset) || !empty($CFG->allowusermailcharset))) {

        // use the defined site mail charset or eventually the one preferred by the recipient
        $charset = $CFG->sitemailcharset;
        if (!empty($CFG->allowusermailcharset)) {
            if ($useremailcharset = get_user_preferences('mailcharset', '0', $user->id)) {
                $charset = $useremailcharset;
            }
        }

        // convert all the necessary strings if the charset is supported
        $charsets = get_list_of_charsets();
        unset($charsets['UTF-8']);
        if (in_array($charset, $charsets)) {
            $textlib = textlib_get_instance();
            $mail->CharSet  = $charset;
            $mail->FromName = $textlib->convert($mail->FromName, 'utf-8', strtolower($charset));
            $mail->Subject  = $textlib->convert($mail->Subject, 'utf-8', strtolower($charset));
            $mail->Body     = $textlib->convert($mail->Body, 'utf-8', strtolower($charset));
            $mail->AltBody  = $textlib->convert($mail->AltBody, 'utf-8', strtolower($charset));

            foreach ($temprecipients as $key => $values) {
                $temprecipients[$key][1] = $textlib->convert($values[1], 'utf-8', strtolower($charset));
            }
            foreach ($tempreplyto as $key => $values) {
                $tempreplyto[$key][1] = $textlib->convert($values[1], 'utf-8', strtolower($charset));
            }
        }
    }

    foreach ($temprecipients as $values) {
        $mail->AddAddress($values[0], $values[1]);
    }
    foreach ($tempreplyto as $values) {
        $mail->AddReplyTo($values[0], $values[1]);
    }

    if ($mail->Send()) {
        set_send_count($user);
        $mail->IsSMTP();                               // use SMTP directly
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return true;
    } else {
        mtrace('ERROR: '. $mail->ErrorInfo);
        add_to_log(SITEID, 'library', 'mailer', $FULLME, 'ERROR: '. $mail->ErrorInfo);
        if (!empty($mail->SMTPDebug)) {
            echo '</pre>';
        }
        return false;
    }
}

function generate_email_signoff() {
    global $CFG;

    $signoff = "\n";
    if (!empty($CFG->supportname)) {
        $signoff .= $CFG->supportname."\n";
    }
    if (!empty($CFG->supportemail)) {
        $signoff .= $CFG->supportemail."\n";
    }
    if (!empty($CFG->supportpage)) {
        $signoff .= $CFG->supportpage."\n";
    }
    return $signoff;
}

function generate_email_supportuser() {
    global $CFG;

    static $supportuser;

    if (!empty($supportuser)) {
        return $supportuser;
    }

    $supportuser = new stdClass();
    $supportuser->email = $CFG->supportemail ? $CFG->supportemail : $CFG->noreplyaddress;
    $supportuser->firstname = $CFG->supportname ? $CFG->supportname : get_string('noreplyname');
    $supportuser->lastname = '';
    $supportuser->maildisplay = true;

    return $supportuser;
}


function setnew_password_and_mail($user) {
    global $CFG, $DB;

    $site  = get_site();

    $supportuser = generate_email_supportuser();

    $newpassword = generate_password();

    $DB->set_field('user', 'password', hash_internal_user_password($newpassword), array('id'=>$user->id));

    $a = new stdClass();
    $a->firstname   = fullname($user, true);
    $a->sitename    = format_string($site->fullname);
    $a->username    = $user->username;
    $a->newpassword = $newpassword;
    $a->link        = $CFG->wwwroot .'/login/';
    $a->signoff     = generate_email_signoff();

    $message = get_string('newusernewpasswordtext', '', $a);

    $subject = format_string($site->fullname) .': '. get_string('newusernewpasswordsubj');

    //directly email rather than using the messaging system to ensure its not routed to a popup or jabber
    return email_to_user($user, $supportuser, $subject, $message);

}

function reset_password_and_mail($user) {
    global $CFG;

    $site  = get_site();
    $supportuser = generate_email_supportuser();

    $userauth = get_auth_plugin($user->auth);
    if (!$userauth->can_reset_password() or !is_enabled_auth($user->auth)) {
        trigger_error("Attempt to reset user password for user $user->username with Auth $user->auth.");
        return false;
    }

    $newpassword = generate_password();

    if (!$userauth->user_update_password($user, $newpassword)) {
        print_error("cannotsetpassword");
    }

    $a = new stdClass();
    $a->firstname   = $user->firstname;
    $a->lastname    = $user->lastname;
    $a->sitename    = format_string($site->fullname);
    $a->username    = $user->username;
    $a->newpassword = $newpassword;
    $a->link        = $CFG->httpswwwroot .'/login/change_password.php';
    $a->signoff     = generate_email_signoff();

    $message = get_string('newpasswordtext', '', $a);

    $subject  = format_string($site->fullname) .': '. get_string('changedpassword');

    unset_user_preference('create_password', $user); // prevent cron from generating the password

    //directly email rather than using the messaging system to ensure its not routed to a popup or jabber
    return email_to_user($user, $supportuser, $subject, $message);

}

 function send_confirmation_email($user) {
    global $CFG;

    $site = get_site();
    $supportuser = generate_email_supportuser();

    $data = new stdClass();
    $data->firstname = fullname($user);
    $data->sitename  = format_string($site->fullname);
    $data->admin     = generate_email_signoff();

    $subject = get_string('emailconfirmationsubject', '', format_string($site->fullname));

    $data->link  = $CFG->wwwroot .'/login/confirm.php?data='. $user->secret .'/'. urlencode($user->username);
    $message     = get_string('emailconfirmation', '', $data);
    $messagehtml = text_to_html(get_string('emailconfirmation', '', $data), false, false, true);

    $user->mailformat = 1;  // Always send HTML version as well

    //directly email rather than using the messaging system to ensure its not routed to a popup or jabber
    return email_to_user($user, $supportuser, $subject, $message, $messagehtml);

}

function send_password_change_confirmation_email($user) {
    global $CFG;

    $site = get_site();
    $supportuser = generate_email_supportuser();

    $data = new stdClass();
    $data->firstname = $user->firstname;
    $data->lastname  = $user->lastname;
    $data->sitename  = format_string($site->fullname);
    $data->link      = $CFG->httpswwwroot .'/login/forgot_password.php?p='. $user->secret .'&s='. urlencode($user->username);
    $data->admin     = generate_email_signoff();

    $message = get_string('emailpasswordconfirmation', '', $data);
    $subject = get_string('emailpasswordconfirmationsubject', '', format_string($site->fullname));

    //directly email rather than using the messaging system to ensure its not routed to a popup or jabber
    return email_to_user($user, $supportuser, $subject, $message);

}

function send_password_change_info($user) {
    global $CFG;

    $site = get_site();
    $supportuser = generate_email_supportuser();
    $systemcontext = get_context_instance(CONTEXT_SYSTEM);

    $data = new stdClass();
    $data->firstname = $user->firstname;
    $data->lastname  = $user->lastname;
    $data->sitename  = format_string($site->fullname);
    $data->admin     = generate_email_signoff();

    $userauth = get_auth_plugin($user->auth);

    if (!is_enabled_auth($user->auth) or $user->auth == 'nologin') {
        $message = get_string('emailpasswordchangeinfodisabled', '', $data);
        $subject = get_string('emailpasswordchangeinfosubject', '', format_string($site->fullname));
        //directly email rather than using the messaging system to ensure its not routed to a popup or jabber
        return email_to_user($user, $supportuser, $subject, $message);
    }

    if ($userauth->can_change_password() and $userauth->change_password_url()) {
        // we have some external url for password changing
        $data->link .= $userauth->change_password_url();

    } else {
        //no way to change password, sorry
        $data->link = '';
    }

    if (!empty($data->link) and has_capability('moodle/user:changeownpassword', $systemcontext, $user->id)) {
        $message = get_string('emailpasswordchangeinfo', '', $data);
        $subject = get_string('emailpasswordchangeinfosubject', '', format_string($site->fullname));
    } else {
        $message = get_string('emailpasswordchangeinfofail', '', $data);
        $subject = get_string('emailpasswordchangeinfosubject', '', format_string($site->fullname));
    }

    //directly email rather than using the messaging system to ensure its not routed to a popup or jabber
    return email_to_user($user, $supportuser, $subject, $message);

}

function email_is_not_allowed($email) {
    global $CFG;

    if (!empty($CFG->allowemailaddresses)) {
        $allowed = explode(' ', $CFG->allowemailaddresses);
        foreach ($allowed as $allowedpattern) {
            $allowedpattern = trim($allowedpattern);
            if (!$allowedpattern) {
                continue;
            }
            if (strpos($allowedpattern, '.') === 0) {
                if (strpos(strrev($email), strrev($allowedpattern)) === 0) {
                    // subdomains are in a form ".example.com" - matches "xxx@anything.example.com"
                    return false;
                }

            } else if (strpos(strrev($email), strrev('@'.$allowedpattern)) === 0) { // Match!   (bug 5250)
                return false;
            }
        }
        return get_string('emailonlyallowed', '', $CFG->allowemailaddresses);

    } else if (!empty($CFG->denyemailaddresses)) {
        $denied = explode(' ', $CFG->denyemailaddresses);
        foreach ($denied as $deniedpattern) {
            $deniedpattern = trim($deniedpattern);
            if (!$deniedpattern) {
                continue;
            }
            if (strpos($deniedpattern, '.') === 0) {
                if (strpos(strrev($email), strrev($deniedpattern)) === 0) {
                    // subdomains are in a form ".example.com" - matches "xxx@anything.example.com"
                    return get_string('emailnotallowed', '', $CFG->denyemailaddresses);
                }

            } else if (strpos(strrev($email), strrev('@'.$deniedpattern)) === 0) { // Match!   (bug 5250)
                return get_string('emailnotallowed', '', $CFG->denyemailaddresses);
            }
        }
    }

    return false;
}


function get_file_storage() {
    global $CFG;

    static $fs = null;

    if ($fs) {
        return $fs;
    }

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

    if (isset($CFG->filedir)) {
        $filedir = $CFG->filedir;
    } else {
        $filedir = $CFG->dataroot.'/filedir';
    }

    if (isset($CFG->trashdir)) {
        $trashdirdir = $CFG->trashdir;
    } else {
        $trashdirdir = $CFG->dataroot.'/trashdir';
    }

    $fs = new file_storage($filedir, $trashdirdir, "$CFG->tempdir/filestorage", $CFG->directorypermissions, $CFG->filepermissions);

    return $fs;
}

function get_file_browser() {
    global $CFG;

    static $fb = null;

    if ($fb) {
        return $fb;
    }

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

    $fb = new file_browser();

    return $fb;
}

function get_file_packer($mimetype='application/zip') {
    global $CFG;

    static $fp = array();;

    if (isset($fp[$mimetype])) {
        return $fp[$mimetype];
    }

    switch ($mimetype) {
        case 'application/zip':
        case 'application/vnd.moodle.backup':
            $classname = 'zip_packer';
            break;
        case 'application/x-tar':
//            $classname = 'tar_packer';
//            break;
        default:
            return false;
    }

    require_once("$CFG->libdir/filestorage/$classname.php");
    $fp[$mimetype] = new $classname();

    return $fp[$mimetype];
}

function valid_uploaded_file($newfile) {
    if (empty($newfile)) {
        return '';
    }
    if (is_uploaded_file($newfile['tmp_name']) and $newfile['size'] > 0) {
        return $newfile['tmp_name'];
    } else {
        return '';
    }
}

function get_max_upload_file_size($sitebytes=0, $coursebytes=0, $modulebytes=0) {

    if (! $filesize = ini_get('upload_max_filesize')) {
        $filesize = '5M';
    }
    $minimumsize = get_real_size($filesize);

    if ($postsize = ini_get('post_max_size')) {
        $postsize = get_real_size($postsize);
        if ($postsize < $minimumsize) {
            $minimumsize = $postsize;
        }
    }

    if ($sitebytes and $sitebytes < $minimumsize) {
        $minimumsize = $sitebytes;
    }

    if ($coursebytes and $coursebytes < $minimumsize) {
        $minimumsize = $coursebytes;
    }

    if ($modulebytes and $modulebytes < $minimumsize) {
        $minimumsize = $modulebytes;
    }

    return $minimumsize;
}

function get_max_upload_sizes($sitebytes=0, $coursebytes=0, $modulebytes=0) {
    global $CFG;

    if (!$maxsize = get_max_upload_file_size($sitebytes, $coursebytes, $modulebytes)) {
        return array();
    }

    $filesize[intval($maxsize)] = display_size($maxsize);

    $sizelist = array(10240, 51200, 102400, 512000, 1048576, 2097152,
                      5242880, 10485760, 20971520, 52428800, 104857600);

    // Allow maxbytes to be selected if it falls outside the above boundaries
    if (isset($CFG->maxbytes) && !in_array(get_real_size($CFG->maxbytes), $sizelist)) {
        // note: get_real_size() is used in order to prevent problems with invalid values
        $sizelist[] = get_real_size($CFG->maxbytes);
    }

    foreach ($sizelist as $sizebytes) {
       if ($sizebytes < $maxsize) {
           $filesize[intval($sizebytes)] = display_size($sizebytes);
       }
    }

    krsort($filesize, SORT_NUMERIC);

    return $filesize;
}

function get_directory_list($rootdir, $excludefiles='', $descend=true, $getdirs=false, $getfiles=true) {

    $dirs = array();

    if (!$getdirs and !$getfiles) {   // Nothing to show
        return $dirs;
    }

    if (!is_dir($rootdir)) {          // Must be a directory
        return $dirs;
    }

    if (!$dir = opendir($rootdir)) {  // Can't open it for some reason
        return $dirs;
    }

    if (!is_array($excludefiles)) {
        $excludefiles = array($excludefiles);
    }

    while (false !== ($file = readdir($dir))) {
        $firstchar = substr($file, 0, 1);
        if ($firstchar == '.' or $file == 'CVS' or in_array($file, $excludefiles)) {
            continue;
        }
        $fullfile = $rootdir .'/'. $file;
        if (filetype($fullfile) == 'dir') {
            if ($getdirs) {
                $dirs[] = $file;
            }
            if ($descend) {
                $subdirs = get_directory_list($fullfile, $excludefiles, $descend, $getdirs, $getfiles);
                foreach ($subdirs as $subdir) {
                    $dirs[] = $file .'/'. $subdir;
                }
            }
        } else if ($getfiles) {
            $dirs[] = $file;
        }
    }
    closedir($dir);

    asort($dirs);

    return $dirs;
}


function get_directory_size($rootdir, $excludefile='') {
    global $CFG;

    // do it this way if we can, it's much faster
    if (!empty($CFG->pathtodu) && is_executable(trim($CFG->pathtodu))) {
        $command = trim($CFG->pathtodu).' -sk '.escapeshellarg($rootdir);
        $output = null;
        $return = null;
        exec($command,$output,$return);
        if (is_array($output)) {
            return get_real_size(intval($output[0]).'k'); // we told it to return k.
        }
    }

    if (!is_dir($rootdir)) {          // Must be a directory
        return 0;
    }

    if (!$dir = @opendir($rootdir)) {  // Can't open it for some reason
        return 0;
    }

    $size = 0;

    while (false !== ($file = readdir($dir))) {
        $firstchar = substr($file, 0, 1);
        if ($firstchar == '.' or $file == 'CVS' or $file == $excludefile) {
            continue;
        }
        $fullfile = $rootdir .'/'. $file;
        if (filetype($fullfile) == 'dir') {
            $size += get_directory_size($fullfile, $excludefile);
        } else {
            $size += filesize($fullfile);
        }
    }
    closedir($dir);

    return $size;
}

function display_size($size) {

    static $gb, $mb, $kb, $b;

    if (empty($gb)) {
        $gb = get_string('sizegb');
        $mb = get_string('sizemb');
        $kb = get_string('sizekb');
        $b  = get_string('sizeb');
    }

    if ($size >= 1073741824) {
        $size = round($size / 1073741824 * 10) / 10 . $gb;
    } else if ($size >= 1048576) {
        $size = round($size / 1048576 * 10) / 10 . $mb;
    } else if ($size >= 1024) {
        $size = round($size / 1024 * 10) / 10 . $kb;
    } else {
        $size = intval($size) .' '. $b; // file sizes over 2GB can not work in 32bit PHP anyway
    }
    return $size;
}

function clean_filename($string) {
    return clean_param($string, PARAM_FILE);
}



function current_language() {
    global $CFG, $USER, $SESSION, $COURSE;

    if (!empty($COURSE->id) and $COURSE->id != SITEID and !empty($COURSE->lang)) {    // Course language can override all other settings for this page
        $return = $COURSE->lang;

    } else if (!empty($SESSION->lang)) {    // Session language can override other settings
        $return = $SESSION->lang;

    } else if (!empty($USER->lang)) {
        $return = $USER->lang;

    } else if (isset($CFG->lang)) {
        $return = $CFG->lang;

    } else {
        $return = 'en';
    }

    $return = str_replace('_utf8', '', $return);  // Just in case this slipped in from somewhere by accident

    return $return;
}

function get_parent_language($lang=null) {
    global $COURSE, $SESSION;

    //let's hack around the current language
    if (!empty($lang)) {
        $old_course_lang  = empty($COURSE->lang) ? '' : $COURSE->lang;
        $old_session_lang = empty($SESSION->lang) ? '' : $SESSION->lang;
        $COURSE->lang  = '';
        $SESSION->lang = $lang;
    }

    $parentlang = get_string('parentlanguage', 'langconfig');
    if ($parentlang === 'en') {
        $parentlang = '';
    }

    //let's hack around the current language
    if (!empty($lang)) {
        $COURSE->lang  = $old_course_lang;
        $SESSION->lang = $old_session_lang;
    }

    return $parentlang;
}

function get_string_manager($forcereload=false) {
    global $CFG;

    static $singleton = null;

    if ($forcereload) {
        $singleton = null;
    }
    if ($singleton === null) {
        if (empty($CFG->early_install_lang)) {

            if (empty($CFG->langcacheroot)) {
                $langcacheroot = $CFG->cachedir . '/lang';
            } else {
                $langcacheroot = $CFG->langcacheroot;
            }

            if (empty($CFG->langlist)) {
                 $translist = array();
            } else {
                $translist = explode(',', $CFG->langlist);
            }

            if (empty($CFG->langmenucachefile)) {
                $langmenucache = $CFG->cachedir . '/languages';
            } else {
                $langmenucache = $CFG->langmenucachefile;
            }

            $singleton = new core_string_manager($CFG->langotherroot, $CFG->langlocalroot, $langcacheroot,
                                                 !empty($CFG->langstringcache), $translist, $langmenucache);

        } else {
            $singleton = new install_string_manager();
        }
    }

    return $singleton;
}


interface string_manager {
    public function get_string($identifier, $component = '', $a = NULL, $lang = NULL);

    public function string_exists($identifier, $component);

    public function get_list_of_countries($returnall = false, $lang = NULL);

    public function get_list_of_languages($lang = NULL, $standard = 'iso6392');

    public function translation_exists($lang, $includeall = true);

    public function get_list_of_translations($returnall = false);

    public function get_list_of_currencies($lang = NULL);

    public function load_component_strings($component, $lang, $disablecache=false, $disablelocal=false);

    public function reset_caches();
}


class core_string_manager implements string_manager {
    protected $otherroot;
    protected $localroot;
    protected $cacheroot;
    protected $cache = array();
    protected $countgetstring = 0;
    protected $countmemcache = 0;
    protected $countdiskcache = 0;
    protected $usediskcache;
    /* @var array limit list of translations */
    protected $translist;
    protected $menucache;

    public function __construct($otherroot, $localroot, $cacheroot, $usediskcache, $translist, $menucache) {
        $this->otherroot    = $otherroot;
        $this->localroot    = $localroot;
        $this->cacheroot    = $cacheroot;
        $this->usediskcache = $usediskcache;
        $this->translist    = $translist;
        $this->menucache    = $menucache;
    }

    public function get_language_dependencies($lang) {
        if ($lang === 'en') {
            return array();
        }
        if (!file_exists("$this->otherroot/$lang/langconfig.php")) {
            return array();
        }
        $string = array();
        include("$this->otherroot/$lang/langconfig.php");

        if (empty($string['parentlanguage'])) {
            return array($lang);
        } else {
            $parentlang = $string['parentlanguage'];
            unset($string);
            return array_merge($this->get_language_dependencies($parentlang), array($lang));
        }
    }

    public function load_component_strings($component, $lang, $disablecache=false, $disablelocal=false) {
        global $CFG;

        list($plugintype, $pluginname) = normalize_component($component);
        if ($plugintype == 'core' and is_null($pluginname)) {
            $component = 'core';
        } else {
            $component = $plugintype . '_' . $pluginname;
        }

        if (!$disablecache) {
            // try in-memory cache first
            if (isset($this->cache[$lang][$component])) {
                $this->countmemcache++;
                return $this->cache[$lang][$component];
            }

            // try on-disk cache then
            if ($this->usediskcache and file_exists($this->cacheroot . "/$lang/$component.php")) {
                $this->countdiskcache++;
                include($this->cacheroot . "/$lang/$component.php");
                return $this->cache[$lang][$component];
            }
        }

        // no cache found - let us merge all possible sources of the strings
        if ($plugintype === 'core') {
            $file = $pluginname;
            if ($file === null) {
                $file = 'moodle';
            }
            $string = array();
            // first load english pack
            if (!file_exists("$CFG->dirroot/lang/en/$file.php")) {
                return array();
            }
            include("$CFG->dirroot/lang/en/$file.php");
            $originalkeys = array_keys($string);
            $originalkeys = array_flip($originalkeys);

            // and then corresponding local if present and allowed
            if (!$disablelocal and file_exists("$this->localroot/en_local/$file.php")) {
                include("$this->localroot/en_local/$file.php");
            }
            // now loop through all langs in correct order
            $deps = $this->get_language_dependencies($lang);
            foreach ($deps as $dep) {
                // the main lang string location
                if (file_exists("$this->otherroot/$dep/$file.php")) {
                    include("$this->otherroot/$dep/$file.php");
                }
                if (!$disablelocal and file_exists("$this->localroot/{$dep}_local/$file.php")) {
                    include("$this->localroot/{$dep}_local/$file.php");
                }
            }

        } else {
            if (!$location = get_plugin_directory($plugintype, $pluginname) or !is_dir($location)) {
                return array();
            }
            if ($plugintype === 'mod') {
                // bloody mod hack
                $file = $pluginname;
            } else {
                $file = $plugintype . '_' . $pluginname;
            }
            $string = array();
            // first load English pack
            if (!file_exists("$location/lang/en/$file.php")) {
                //English pack does not exist, so do not try to load anything else
                return array();
            }
            include("$location/lang/en/$file.php");
            $originalkeys = array_keys($string);
            $originalkeys = array_flip($originalkeys);
            // and then corresponding local english if present
            if (!$disablelocal and file_exists("$this->localroot/en_local/$file.php")) {
                include("$this->localroot/en_local/$file.php");
            }

            // now loop through all langs in correct order
            $deps = $this->get_language_dependencies($lang);
            foreach ($deps as $dep) {
                // legacy location - used by contrib only
                if (file_exists("$location/lang/$dep/$file.php")) {
                    include("$location/lang/$dep/$file.php");
                }
                // the main lang string location
                if (file_exists("$this->otherroot/$dep/$file.php")) {
                    include("$this->otherroot/$dep/$file.php");
                }
                // local customisations
                if (!$disablelocal and file_exists("$this->localroot/{$dep}_local/$file.php")) {
                    include("$this->localroot/{$dep}_local/$file.php");
                }
            }
        }

        // we do not want any extra strings from other languages - everything must be in en lang pack
        $string = array_intersect_key($string, $originalkeys);

        // now we have a list of strings from all possible sources. put it into both in-memory and on-disk
        // caches so we do not need to do all this merging and dependencies resolving again
        $this->cache[$lang][$component] = $string;
        if ($this->usediskcache) {
            check_dir_exists("$this->cacheroot/$lang");
            file_put_contents("$this->cacheroot/$lang/$component.php", "<?php \$this->cache['$lang']['$component'] = ".var_export($string, true).";");
        }
        return $string;
    }

    public function string_exists($identifier, $component) {
       $identifier = clean_param($identifier, PARAM_STRINGID);
        if (empty($identifier)) {
            return false;
        }
        $lang = current_language();
        $string = $this->load_component_strings($component, $lang);
        return isset($string[$identifier]);
    }

    public function get_string($identifier, $component = '', $a = NULL, $lang = NULL) {
        $this->countgetstring++;
        // there are very many uses of these time formating strings without the 'langconfig' component,
        // it would not be reasonable to expect that all of them would be converted during 2.0 migration
        static $langconfigstrs = array(
                'strftimedate' => 1,
                'strftimedatefullshort' => 1,
                'strftimedateshort' => 1,
                'strftimedatetime' => 1,
                'strftimedatetimeshort' => 1,
                'strftimedaydate' => 1,
                'strftimedaydatetime' => 1,
                'strftimedayshort' => 1,
                'strftimedaytime' => 1,
                'strftimemonthyear' => 1,
                'strftimerecent' => 1,
                'strftimerecentfull' => 1,
                'strftimetime' => 1);

        if (empty($component)) {
            if (isset($langconfigstrs[$identifier])) {
                $component = 'langconfig';
            } else {
                $component = 'moodle';
            }
        }

        if ($lang === NULL) {
            $lang = current_language();
        }

        $string = $this->load_component_strings($component, $lang);

        if (!isset($string[$identifier])) {
            if ($component === 'pix' or $component === 'core_pix') {
                // this component contains only alt tags for emoticons,
                // not all of them are supposed to be defined
                return '';
            }
            if ($identifier === 'parentlanguage' and ($component === 'langconfig' or $component === 'core_langconfig')) {
                // parentlanguage is a special string, undefined means use English if not defined
                return 'en';
            }
            if ($this->usediskcache) {
                // maybe the on-disk cache is dirty - let the last attempt be to find the string in original sources
                $string = $this->load_component_strings($component, $lang, true);
            }
            if (!isset($string[$identifier])) {
                // the string is still missing - should be fixed by developer
                list($plugintype, $pluginname) = normalize_component($component);
                if ($plugintype == 'core') {
                    $file = "lang/en/{$component}.php";
                } else if ($plugintype == 'mod') {
                    $file = "mod/{$pluginname}/lang/en/{$pluginname}.php";
                } else {
                    $path = get_plugin_directory($plugintype, $pluginname);
                    $file = "{$path}/lang/en/{$plugintype}_{$pluginname}.php";
                }
                debugging("Invalid get_string() identifier: '{$identifier}' or component '{$component}'. " .
                        "Perhaps you are missing \$string['{$identifier}'] = ''; in {$file}?", DEBUG_DEVELOPER);
                return "[[$identifier]]";
            }
        }

        $string = $string[$identifier];

        if ($a !== NULL) {
            if (is_object($a) or is_array($a)) {
                $a = (array)$a;
                $search = array();
                $replace = array();
                foreach ($a as $key=>$value) {
                    if (is_int($key)) {
                        // we do not support numeric keys - sorry!
                        continue;
                    }
                    if (is_object($value) or is_array($value)) {
                        // we support just string as value
                        continue;
                    }
                    $search[]  = '{$a->'.$key.'}';
                    $replace[] = (string)$value;
                }
                if ($search) {
                    $string = str_replace($search, $replace, $string);
                }
            } else {
                $string = str_replace('{$a}', (string)$a, $string);
            }
        }

        return $string;
    }

    public function get_performance_summary() {
        return array(array(
            'langcountgetstring' => $this->countgetstring,
            'langcountmemcache' => $this->countmemcache,
            'langcountdiskcache' => $this->countdiskcache,
        ), array(
            'langcountgetstring' => 'get_string calls',
            'langcountmemcache' => 'strings mem cache hits',
            'langcountdiskcache' => 'strings disk cache hits',
        ));
    }

    public function get_list_of_countries($returnall = false, $lang = NULL) {
        global $CFG;

        if ($lang === NULL) {
            $lang = current_language();
        }

        $countries = $this->load_component_strings('core_countries', $lang);
        collatorlib::asort($countries);
        if (!$returnall and !empty($CFG->allcountrycodes)) {
            $enabled = explode(',', $CFG->allcountrycodes);
            $return = array();
            foreach ($enabled as $c) {
                if (isset($countries[$c])) {
                    $return[$c] = $countries[$c];
                }
            }
            return $return;
        }

        return $countries;
    }

    public function get_list_of_languages($lang = NULL, $standard = 'iso6391') {
        if ($lang === NULL) {
            $lang = current_language();
        }

        if ($standard === 'iso6392') {
            $langs = $this->load_component_strings('core_iso6392', $lang);
            ksort($langs);
            return $langs;

        } else if ($standard === 'iso6391') {
            $langs2 = $this->load_component_strings('core_iso6392', $lang);
            static $mapping = array('aar' => 'aa', 'abk' => 'ab', 'afr' => 'af', 'aka' => 'ak', 'sqi' => 'sq', 'amh' => 'am', 'ara' => 'ar', 'arg' => 'an', 'hye' => 'hy',
                'asm' => 'as', 'ava' => 'av', 'ave' => 'ae', 'aym' => 'ay', 'aze' => 'az', 'bak' => 'ba', 'bam' => 'bm', 'eus' => 'eu', 'bel' => 'be', 'ben' => 'bn', 'bih' => 'bh',
                'bis' => 'bi', 'bos' => 'bs', 'bre' => 'br', 'bul' => 'bg', 'mya' => 'my', 'cat' => 'ca', 'cha' => 'ch', 'che' => 'ce', 'zho' => 'zh', 'chu' => 'cu', 'chv' => 'cv',
                'cor' => 'kw', 'cos' => 'co', 'cre' => 'cr', 'ces' => 'cs', 'dan' => 'da', 'div' => 'dv', 'nld' => 'nl', 'dzo' => 'dz', 'eng' => 'en', 'epo' => 'eo', 'est' => 'et',
                'ewe' => 'ee', 'fao' => 'fo', 'fij' => 'fj', 'fin' => 'fi', 'fra' => 'fr', 'fry' => 'fy', 'ful' => 'ff', 'kat' => 'ka', 'deu' => 'de', 'gla' => 'gd', 'gle' => 'ga',
                'glg' => 'gl', 'glv' => 'gv', 'ell' => 'el', 'grn' => 'gn', 'guj' => 'gu', 'hat' => 'ht', 'hau' => 'ha', 'heb' => 'he', 'her' => 'hz', 'hin' => 'hi', 'hmo' => 'ho',
                'hrv' => 'hr', 'hun' => 'hu', 'ibo' => 'ig', 'isl' => 'is', 'ido' => 'io', 'iii' => 'ii', 'iku' => 'iu', 'ile' => 'ie', 'ina' => 'ia', 'ind' => 'id', 'ipk' => 'ik',
                'ita' => 'it', 'jav' => 'jv', 'jpn' => 'ja', 'kal' => 'kl', 'kan' => 'kn', 'kas' => 'ks', 'kau' => 'kr', 'kaz' => 'kk', 'khm' => 'km', 'kik' => 'ki', 'kin' => 'rw',
                'kir' => 'ky', 'kom' => 'kv', 'kon' => 'kg', 'kor' => 'ko', 'kua' => 'kj', 'kur' => 'ku', 'lao' => 'lo', 'lat' => 'la', 'lav' => 'lv', 'lim' => 'li', 'lin' => 'ln',
                'lit' => 'lt', 'ltz' => 'lb', 'lub' => 'lu', 'lug' => 'lg', 'mkd' => 'mk', 'mah' => 'mh', 'mal' => 'ml', 'mri' => 'mi', 'mar' => 'mr', 'msa' => 'ms', 'mlg' => 'mg',
                'mlt' => 'mt', 'mon' => 'mn', 'nau' => 'na', 'nav' => 'nv', 'nbl' => 'nr', 'nde' => 'nd', 'ndo' => 'ng', 'nep' => 'ne', 'nno' => 'nn', 'nob' => 'nb', 'nor' => 'no',
                'nya' => 'ny', 'oci' => 'oc', 'oji' => 'oj', 'ori' => 'or', 'orm' => 'om', 'oss' => 'os', 'pan' => 'pa', 'fas' => 'fa', 'pli' => 'pi', 'pol' => 'pl', 'por' => 'pt',
                'pus' => 'ps', 'que' => 'qu', 'roh' => 'rm', 'ron' => 'ro', 'run' => 'rn', 'rus' => 'ru', 'sag' => 'sg', 'san' => 'sa', 'sin' => 'si', 'slk' => 'sk', 'slv' => 'sl',
                'sme' => 'se', 'smo' => 'sm', 'sna' => 'sn', 'snd' => 'sd', 'som' => 'so', 'sot' => 'st', 'spa' => 'es', 'srd' => 'sc', 'srp' => 'sr', 'ssw' => 'ss', 'sun' => 'su',
                'swa' => 'sw', 'swe' => 'sv', 'tah' => 'ty', 'tam' => 'ta', 'tat' => 'tt', 'tel' => 'te', 'tgk' => 'tg', 'tgl' => 'tl', 'tha' => 'th', 'bod' => 'bo', 'tir' => 'ti',
                'ton' => 'to', 'tsn' => 'tn', 'tso' => 'ts', 'tuk' => 'tk', 'tur' => 'tr', 'twi' => 'tw', 'uig' => 'ug', 'ukr' => 'uk', 'urd' => 'ur', 'uzb' => 'uz', 'ven' => 've',
                'vie' => 'vi', 'vol' => 'vo', 'cym' => 'cy', 'wln' => 'wa', 'wol' => 'wo', 'xho' => 'xh', 'yid' => 'yi', 'yor' => 'yo', 'zha' => 'za', 'zul' => 'zu');
            $langs1 = array();
            foreach ($mapping as $c2=>$c1) {
                $langs1[$c1] = $langs2[$c2];
            }
            ksort($langs1);
            return $langs1;

        } else {
            debugging('Unsupported $standard parameter in get_list_of_languages() method: '.$standard);
        }

        return array();
    }

    public function translation_exists($lang, $includeall = true) {

        if (strpos($lang, '_local') !== false) {
            // _local packs are not real translations
            return false;
        }
        if (!$includeall and !empty($this->translist)) {
            if (!in_array($lang, $this->translist)) {
                return false;
            }
        }
        if ($lang === 'en') {
            // part of distribution
            return true;
        }
        return file_exists("$this->otherroot/$lang/langconfig.php");
    }

    public function get_list_of_translations($returnall = false) {
        global $CFG;

        $languages = array();

        if (!empty($CFG->langcache) and is_readable($this->menucache)) {
            // try to re-use the cached list of all available languages
            $cachedlist = json_decode(file_get_contents($this->menucache), true);

            if (is_array($cachedlist) and !empty($cachedlist)) {
                // the cache file is restored correctly

                if (!$returnall and !empty($this->translist)) {
                    // return just enabled translations
                    foreach ($cachedlist as $langcode => $langname) {
                        if (in_array($langcode, $this->translist)) {
                            $languages[$langcode] = $langname;
                        }
                    }
                    return $languages;

                } else {
                    // return all translations
                    return $cachedlist;
                }
            }
        }

        // the cached list of languages is not available, let us populate the list

        if (!$returnall and !empty($this->translist)) {
            // return only some translations
            foreach ($this->translist as $lang) {
                $lang = trim($lang);   //Just trim spaces to be a bit more permissive
                if (strstr($lang, '_local') !== false) {
                    continue;
                }
                if (strstr($lang, '_utf8') !== false) {
                    continue;
                }
                if ($lang !== 'en' and !file_exists("$this->otherroot/$lang/langconfig.php")) {
                    // some broken or missing lang - can not switch to it anyway
                    continue;
                }
                $string = $this->load_component_strings('langconfig', $lang);
                if (!empty($string['thislanguage'])) {
                    $languages[$lang] = $string['thislanguage'].' ('. $lang .')';
                }
                unset($string);
            }

        } else {
            // return all languages available in system
            $langdirs = get_list_of_plugins('', '', $this->otherroot);

            $langdirs = array_merge($langdirs, array("$CFG->dirroot/lang/en"=>'en'));
            // Sort all

            // Loop through all langs and get info
            foreach ($langdirs as $lang) {
                if (strstr($lang, '_local') !== false) {
                    continue;
                }
                if (strstr($lang, '_utf8') !== false) {
                    continue;
                }
                $string = $this->load_component_strings('langconfig', $lang);
                if (!empty($string['thislanguage'])) {
                    $languages[$lang] = $string['thislanguage'].' ('. $lang .')';
                }
                unset($string);
            }

            if (!empty($CFG->langcache) and !empty($this->menucache)) {
                // cache the list so that it can be used next time
                collatorlib::asort($languages);
                check_dir_exists(dirname($this->menucache), true, true);
                file_put_contents($this->menucache, json_encode($languages));
            }
        }

        collatorlib::asort($languages);

        return $languages;
    }

    public function get_list_of_currencies($lang = NULL) {
        if ($lang === NULL) {
            $lang = current_language();
        }

        $currencies = $this->load_component_strings('core_currencies', $lang);
        asort($currencies);

        return $currencies;
    }

    public function reset_caches() {
        global $CFG;
        require_once("$CFG->libdir/filelib.php");

        // clear the on-disk disk with aggregated string files
        fulldelete($this->cacheroot);

        // clear the in-memory cache of loaded strings
        $this->cache = array();

        // clear the cache containing the list of available translations
        // and re-populate it again
        fulldelete($this->menucache);
        $this->get_list_of_translations(true);
    }
}


class install_string_manager implements string_manager {
    protected $installroot;

    public function __construct() {
        global $CFG;
        $this->installroot = "$CFG->dirroot/install/lang";
    }

    public function load_component_strings($component, $lang, $disablecache=false, $disablelocal=false) {
        // not needed in installer
        return array();
    }

    public function string_exists($identifier, $component) {
        $identifier = clean_param($identifier, PARAM_STRINGID);
        if (empty($identifier)) {
            return false;
        }
        // simple old style hack ;)
        $str = get_string($identifier, $component);
        return (strpos($str, '[[') === false);
    }

    public function get_string($identifier, $component = '', $a = NULL, $lang = NULL) {
        if (!$component) {
            $component = 'moodle';
        }

        if ($lang === NULL) {
            $lang = current_language();
        }

        //get parent lang
        $parent = '';
        if ($lang !== 'en' and $identifier !== 'parentlanguage' and $component !== 'langconfig') {
            if (file_exists("$this->installroot/$lang/langconfig.php")) {
                $string = array();
                include("$this->installroot/$lang/langconfig.php");
                if (isset($string['parentlanguage'])) {
                    $parent = $string['parentlanguage'];
                }
                unset($string);
            }
        }

        // include en string first
        if (!file_exists("$this->installroot/en/$component.php")) {
            return "[[$identifier]]";
        }
        $string = array();
        include("$this->installroot/en/$component.php");

        // now override en with parent if defined
        if ($parent and $parent !== 'en' and file_exists("$this->installroot/$parent/$component.php")) {
            include("$this->installroot/$parent/$component.php");
        }

        // finally override with requested language
        if ($lang !== 'en' and file_exists("$this->installroot/$lang/$component.php")) {
            include("$this->installroot/$lang/$component.php");
        }

        if (!isset($string[$identifier])) {
            return "[[$identifier]]";
        }

        $string = $string[$identifier];

        if ($a !== NULL) {
            if (is_object($a) or is_array($a)) {
                $a = (array)$a;
                $search = array();
                $replace = array();
                foreach ($a as $key=>$value) {
                    if (is_int($key)) {
                        // we do not support numeric keys - sorry!
                        continue;
                    }
                    $search[]  = '{$a->'.$key.'}';
                    $replace[] = (string)$value;
                }
                if ($search) {
                    $string = str_replace($search, $replace, $string);
                }
            } else {
                $string = str_replace('{$a}', (string)$a, $string);
            }
        }

        return $string;
    }

    public function get_list_of_countries($returnall = false, $lang = NULL) {
        //not used in installer
        return array();
    }

    public function get_list_of_languages($lang = NULL, $standard = 'iso6392') {
        //not used in installer
        return array();
    }

    public function translation_exists($lang, $includeall = true) {
        return file_exists($this->installroot.'/'.$lang.'/langconfig.php');
    }

    public function get_list_of_translations($returnall = false) {
        // return all is ignored here - we need to know all langs in installer
        $languages = array();
        // Get raw list of lang directories
        $langdirs = get_list_of_plugins('install/lang');
        asort($langdirs);
        // Get some info from each lang
        foreach ($langdirs as $lang) {
            if (file_exists($this->installroot.'/'.$lang.'/langconfig.php')) {
                $string = array();
                include($this->installroot.'/'.$lang.'/langconfig.php');
                if (!empty($string['thislanguage'])) {
                    $languages[$lang] = $string['thislanguage'].' ('.$lang.')';
                }
            }
        }
        // Return array
        return $languages;
    }

    public function get_list_of_currencies($lang = NULL) {
        // not used in installer
        return array();
    }

    public function reset_caches() {}
}


function get_string($identifier, $component = '', $a = NULL) {
    global $CFG;

    $identifier = clean_param($identifier, PARAM_STRINGID);
    if (empty($identifier)) {
        throw new coding_exception('Invalid string identifier. Most probably some illegal character is part of the string identifier. Please fix your get_string() call and string definition');
    }

    if (func_num_args() > 3) {
        debugging('extralocations parameter in get_string() is not supported any more, please use standard lang locations only.');
    }

    if (strpos($component, '/') !== false) {
        debugging('The module name you passed to get_string is the deprecated format ' .
                'like mod/mymod or block/myblock. The correct form looks like mymod, or block_myblock.' , DEBUG_DEVELOPER);
        $componentpath = explode('/', $component);

        switch ($componentpath[0]) {
            case 'mod':
                $component = $componentpath[1];
                break;
            case 'blocks':
            case 'block':
                $component = 'block_'.$componentpath[1];
                break;
            case 'enrol':
                $component = 'enrol_'.$componentpath[1];
                break;
            case 'format':
                $component = 'format_'.$componentpath[1];
                break;
            case 'grade':
                $component = 'grade'.$componentpath[1].'_'.$componentpath[2];
                break;
        }
    }

    $result = get_string_manager()->get_string($identifier, $component, $a);

    // Debugging feature lets you display string identifier and component
    if (isset($CFG->debugstringids) && $CFG->debugstringids && optional_param('strings', 0, PARAM_INT)) {
        $result .= ' {' . $identifier . '/' . $component . '}';
    }
    return $result;
}

function get_strings($array, $component = '') {
   $string = new stdClass;
   foreach ($array as $item) {
       $string->$item = get_string($item, $component);
   }
   return $string;
}

function print_string($identifier, $component = '', $a = NULL) {
    echo get_string($identifier, $component, $a);
}

function get_list_of_charsets() {

    $charsets = array(
        'EUC-JP'     => 'EUC-JP',
        'ISO-2022-JP'=> 'ISO-2022-JP',
        'ISO-8859-1' => 'ISO-8859-1',
        'SHIFT-JIS'  => 'SHIFT-JIS',
        'GB2312'     => 'GB2312',
        'GB18030'    => 'GB18030', // gb18030 not supported by typo and mbstring
        'UTF-8'      => 'UTF-8');

    asort($charsets);

    return $charsets;
}

function get_list_of_themes() {
    global $CFG;

    $themes = array();

    if (!empty($CFG->themelist)) {       // use admin's list of themes
        $themelist = explode(',', $CFG->themelist);
    } else {
        $themelist = array_keys(get_plugin_list("theme"));
    }

    foreach ($themelist as $key => $themename) {
        $theme = theme_config::load($themename);
        $themes[$themename] = $theme;
    }

    collatorlib::asort_objects_by_method($themes, 'get_theme_name');

    return $themes;
}

function get_list_of_timezones() {
    global $CFG, $DB;

    static $timezones;

    if (!empty($timezones)) {    // This function has been called recently
        return $timezones;
    }

    $timezones = array();

    if ($rawtimezones = $DB->get_records_sql("SELECT MAX(id), name FROM {timezone} GROUP BY name")) {
        foreach($rawtimezones as $timezone) {
            if (!empty($timezone->name)) {
                if (get_string_manager()->string_exists(strtolower($timezone->name), 'timezones')) {
                    $timezones[$timezone->name] = get_string(strtolower($timezone->name), 'timezones');
                } else {
                    $timezones[$timezone->name] = $timezone->name;
                }
                if (substr($timezones[$timezone->name], 0, 1) == '[') {  // No translation found
                    $timezones[$timezone->name] = $timezone->name;
                }
            }
        }
    }

    asort($timezones);

    for ($i = -13; $i <= 13; $i += .5) {
        $tzstring = 'UTC';
        if ($i < 0) {
            $timezones[sprintf("%.1f", $i)] = $tzstring . $i;
        } else if ($i > 0) {
            $timezones[sprintf("%.1f", $i)] = $tzstring . '+' . $i;
        } else {
            $timezones[sprintf("%.1f", $i)] = $tzstring;
        }
    }

    return $timezones;
}

function get_emoticon_manager() {
    static $singleton = null;

    if (is_null($singleton)) {
        $singleton = new emoticon_manager();
    }

    return $singleton;
}

class emoticon_manager {

    public function get_emoticons() {
        global $CFG;

        if (empty($CFG->emoticons)) {
            return array();
        }

        $emoticons = $this->decode_stored_config($CFG->emoticons);

        if (!is_array($emoticons)) {
            // something is wrong with the format of stored setting
            debugging('Invalid format of emoticons setting, please resave the emoticons settings form', DEBUG_NORMAL);
            return array();
        }

        return $emoticons;
    }

    public function prepare_renderable_emoticon(stdClass $emoticon, array $attributes = array()) {
        $stringmanager = get_string_manager();
        if ($stringmanager->string_exists($emoticon->altidentifier, $emoticon->altcomponent)) {
            $alt = get_string($emoticon->altidentifier, $emoticon->altcomponent);
        } else {
            $alt = s($emoticon->text);
        }
        return new pix_emoticon($emoticon->imagename, $alt, $emoticon->imagecomponent, $attributes);
    }

    public function encode_stored_config(array $emoticons) {
        return json_encode($emoticons);
    }

    public function decode_stored_config($encoded) {
        $decoded = json_decode($encoded);
        if (!is_array($decoded)) {
            return null;
        }
        return $decoded;
    }

    public function default_emoticons() {
        return array(
            $this->prepare_emoticon_object(":-)", 's/smiley', 'smiley'),
            $this->prepare_emoticon_object(":)", 's/smiley', 'smiley'),
            $this->prepare_emoticon_object(":-D", 's/biggrin', 'biggrin'),
            $this->prepare_emoticon_object(";-)", 's/wink', 'wink'),
            $this->prepare_emoticon_object(":-/", 's/mixed', 'mixed'),
            $this->prepare_emoticon_object("V-.", 's/thoughtful', 'thoughtful'),
            $this->prepare_emoticon_object(":-P", 's/tongueout', 'tongueout'),
            $this->prepare_emoticon_object(":-p", 's/tongueout', 'tongueout'),
            $this->prepare_emoticon_object("B-)", 's/cool', 'cool'),
            $this->prepare_emoticon_object("^-)", 's/approve', 'approve'),
            $this->prepare_emoticon_object("8-)", 's/wideeyes', 'wideeyes'),
            $this->prepare_emoticon_object(":o)", 's/clown', 'clown'),
            $this->prepare_emoticon_object(":-(", 's/sad', 'sad'),
            $this->prepare_emoticon_object(":(", 's/sad', 'sad'),
            $this->prepare_emoticon_object("8-.", 's/shy', 'shy'),
            $this->prepare_emoticon_object(":-I", 's/blush', 'blush'),
            $this->prepare_emoticon_object(":-X", 's/kiss', 'kiss'),
            $this->prepare_emoticon_object("8-o", 's/surprise', 'surprise'),
            $this->prepare_emoticon_object("P-|", 's/blackeye', 'blackeye'),
            $this->prepare_emoticon_object("8-[", 's/angry', 'angry'),
            $this->prepare_emoticon_object("(grr)", 's/angry', 'angry'),
            $this->prepare_emoticon_object("xx-P", 's/dead', 'dead'),
            $this->prepare_emoticon_object("|-.", 's/sleepy', 'sleepy'),
            $this->prepare_emoticon_object("}-]", 's/evil', 'evil'),
            $this->prepare_emoticon_object("(h)", 's/heart', 'heart'),
            $this->prepare_emoticon_object("(heart)", 's/heart', 'heart'),
            $this->prepare_emoticon_object("(y)", 's/yes', 'yes', 'core'),
            $this->prepare_emoticon_object("(n)", 's/no', 'no', 'core'),
            $this->prepare_emoticon_object("(martin)", 's/martin', 'martin'),
            $this->prepare_emoticon_object("( )", 's/egg', 'egg'),
        );
    }

    protected function prepare_emoticon_object($text, $imagename, $altidentifier = null, $altcomponent = 'core_pix', $imagecomponent = 'core') {
        return (object)array(
            'text'           => $text,
            'imagename'      => $imagename,
            'imagecomponent' => $imagecomponent,
            'altidentifier'  => $altidentifier,
            'altcomponent'   => $altcomponent,
        );
    }
}


function rc4encrypt($data) {
    $password = get_site_identifier();
    return endecrypt($password, $data, '');
}

function rc4decrypt($data) {
    $password = get_site_identifier();
    return endecrypt($password, $data, 'de');
}

function endecrypt ($pwd, $data, $case) {

    if ($case == 'de') {
        $data = urldecode($data);
    }

    $key[] = '';
    $box[] = '';
    $temp_swap = '';
    $pwd_length = 0;

    $pwd_length = strlen($pwd);

    for ($i = 0; $i <= 255; $i++) {
        $key[$i] = ord(substr($pwd, ($i % $pwd_length), 1));
        $box[$i] = $i;
    }

    $x = 0;

    for ($i = 0; $i <= 255; $i++) {
        $x = ($x + $box[$i] + $key[$i]) % 256;
        $temp_swap = $box[$i];
        $box[$i] = $box[$x];
        $box[$x] = $temp_swap;
    }

    $temp = '';
    $k = '';

    $cipherby = '';
    $cipher = '';

    $a = 0;
    $j = 0;

    for ($i = 0; $i < strlen($data); $i++) {
        $a = ($a + 1) % 256;
        $j = ($j + $box[$a]) % 256;
        $temp = $box[$a];
        $box[$a] = $box[$j];
        $box[$j] = $temp;
        $k = $box[(($box[$a] + $box[$j]) % 256)];
        $cipherby = ord(substr($data, $i, 1)) ^ $k;
        $cipher .= chr($cipherby);
    }

    if ($case == 'de') {
        $cipher = urldecode(urlencode($cipher));
    } else {
        $cipher = urlencode($cipher);
    }

    return $cipher;
}


function get_plugin_directory($plugintype, $name) {
    global $CFG;

    if ($plugintype === '') {
        $plugintype = 'mod';
    }

    $types = get_plugin_types(true);
    if (!array_key_exists($plugintype, $types)) {
        return NULL;
    }
    $name = clean_param($name, PARAM_SAFEDIR); // just in case ;-)

    if (!empty($CFG->themedir) and $plugintype === 'theme') {
        if (!is_dir($types['theme'] . '/' . $name)) {
            // ok, so the theme is supposed to be in the $CFG->themedir
            return $CFG->themedir . '/' . $name;
        }
    }

    return $types[$plugintype].'/'.$name;
}

function get_component_directory($component) {
    global $CFG;
/*
    $simpletest = false;
    if (strpos($component, 'simpletest_') === 0) {
        $subdir = substr($component, strlen('simpletest_'));
        //TODO: this looks borked, where is it used actually?
        return $subdir;
    }
*/
    list($type, $plugin) = normalize_component($component);

    if ($type === 'core') {
        if ($plugin === NULL ) {
            $path = $CFG->libdir;
        } else {
            $subsystems = get_core_subsystems();
            if (isset($subsystems[$plugin])) {
                $path = $CFG->dirroot.'/'.$subsystems[$plugin];
            } else {
                $path = NULL;
            }
        }

    } else {
        $path = get_plugin_directory($type, $plugin);
    }

    return $path;
}

function normalize_component($component) {
    if ($component === 'moodle' or $component === 'core') {
        $type = 'core';
        $plugin = NULL;

    } else if (strpos($component, '_') === false) {
        $subsystems = get_core_subsystems();
        if (array_key_exists($component, $subsystems)) {
            $type   = 'core';
            $plugin = $component;
        } else {
            // everything else is a module
            $type   = 'mod';
            $plugin = $component;
        }

    } else {
        list($type, $plugin) = explode('_', $component, 2);
        $plugintypes = get_plugin_types(false);
        if ($type !== 'core' and !array_key_exists($type, $plugintypes)) {
            $type   = 'mod';
            $plugin = $component;
        }
    }

    return array($type, $plugin);
}

function get_core_subsystems() {
    global $CFG;

    static $info = null;

    if (!$info) {
        $info = array(
            'access'      => NULL,
            'admin'       => $CFG->admin,
            'auth'        => 'auth',
            'backup'      => 'backup/util/ui',
            'block'       => 'blocks',
            'blog'        => 'blog',
            'bulkusers'   => NULL,
            'calendar'    => 'calendar',
            'cohort'      => 'cohort',
            'condition'   => NULL,
            'completion'  => NULL,
            'countries'   => NULL,
            'course'      => 'course',
            'currencies'  => NULL,
            'dbtransfer'  => NULL,
            'debug'       => NULL,
            'dock'        => NULL,
            'editor'      => 'lib/editor',
            'edufields'   => NULL,
            'enrol'       => 'enrol',
            'error'       => NULL,
            'filepicker'  => NULL,
            'files'       => 'files',
            'filters'     => NULL,
            'fonts'       => NULL,
            'form'        => 'lib/form',
            'grades'      => 'grade',
            'grading'     => 'grade/grading',
            'group'       => 'group',
            'help'        => NULL,
            'hub'         => NULL,
            'imscc'       => NULL,
            'install'     => NULL,
            'iso6392'     => NULL,
            'langconfig'  => NULL,
            'license'     => NULL,
            'mathslib'    => NULL,
            'message'     => 'message',
            'mimetypes'   => NULL,
            'mnet'        => 'mnet',
            'moodle.org'  => NULL, // the dot is nasty, watch out! should be renamed to moodleorg
            'my'          => 'my',
            'notes'       => 'notes',
            'pagetype'    => NULL,
            'pix'         => NULL,
            'plagiarism'  => 'plagiarism',
            'plugin'      => NULL,
            'portfolio'   => 'portfolio',
            'publish'     => 'course/publish',
            'question'    => 'question',
            'rating'      => 'rating',
            'register'    => 'admin/registration', //TODO: this is wrong, unfortunately we would need to modify hub code to pass around the correct url
            'repository'  => 'repository',
            'rss'         => 'rss',
            'role'        => $CFG->admin.'/role',
            'search'      => 'search',
            'table'       => NULL,
            'tag'         => 'tag',
            'timezones'   => NULL,
            'user'        => 'user',
            'userkey'     => NULL,
            'webservice'  => 'webservice',
        );
    }

    return $info;
}

function get_plugin_types($fullpaths=true) {
    global $CFG;

    static $info     = null;
    static $fullinfo = null;

    if (!$info) {
        $info = array('qtype'         => 'question/type',
                      'mod'           => 'mod',
                      'auth'          => 'auth',
                      'enrol'         => 'enrol',
                      'message'       => 'message/output',
                      'block'         => 'blocks',
                      'filter'        => 'filter',
                      'editor'        => 'lib/editor',
                      'format'        => 'course/format',
                      'profilefield'  => 'user/profile/field',
                      'report'        => 'report',
                      'coursereport'  => 'course/report', // must be after system reports
                      'gradeexport'   => 'grade/export',
                      'gradeimport'   => 'grade/import',
                      'gradereport'   => 'grade/report',
                      'gradingform'   => 'grade/grading/form',
                      'mnetservice'   => 'mnet/service',
                      'webservice'    => 'webservice',
                      'repository'    => 'repository',
                      'portfolio'     => 'portfolio',
                      'qbehaviour'    => 'question/behaviour',
                      'qformat'       => 'question/format',
                      'plagiarism'    => 'plagiarism',
                      'tool'          => $CFG->admin.'/tool',
                      'theme'         => 'theme',  // this is a bit hacky, themes may be in $CFG->themedir too
        );

        $mods = get_plugin_list('mod');
        foreach ($mods as $mod => $moddir) {
            if (file_exists("$moddir/db/subplugins.php")) {
                $subplugins = array();
                include("$moddir/db/subplugins.php");
                foreach ($subplugins as $subtype=>$dir) {
                    $info[$subtype] = $dir;
                }
            }
        }

        // local is always last!
        $info['local'] = 'local';

        $fullinfo = array();
        foreach ($info as $type => $dir) {
            $fullinfo[$type] = $CFG->dirroot.'/'.$dir;
        }
    }

    return ($fullpaths ? $fullinfo : $info);
}

function get_plugin_list($plugintype) {
    global $CFG;

    $ignored = array('CVS', '_vti_cnf', 'simpletest', 'db', 'yui', 'phpunit');
    if ($plugintype == 'auth') {
        // Historically we have had an auth plugin called 'db', so allow a special case.
        $key = array_search('db', $ignored);
        if ($key !== false) {
            unset($ignored[$key]);
        }
    }

    if ($plugintype === '') {
        $plugintype = 'mod';
    }

    $fulldirs = array();

    if ($plugintype === 'mod') {
        // mod is an exception because we have to call this function from get_plugin_types()
        $fulldirs[] = $CFG->dirroot.'/mod';

    } else if ($plugintype === 'theme') {
        $fulldirs[] = $CFG->dirroot.'/theme';
        // themes are special because they may be stored also in separate directory
        if (!empty($CFG->themedir) and file_exists($CFG->themedir) and is_dir($CFG->themedir) ) {
            $fulldirs[] = $CFG->themedir;
        }

    } else {
        $types = get_plugin_types(true);
        if (!array_key_exists($plugintype, $types)) {
            return array();
        }
        $fulldir = $types[$plugintype];
        if (!file_exists($fulldir)) {
            return array();
        }
        $fulldirs[] = $fulldir;
    }

    $result = array();

    foreach ($fulldirs as $fulldir) {
        if (!is_dir($fulldir)) {
            continue;
        }
        $items = new DirectoryIterator($fulldir);
        foreach ($items as $item) {
            if ($item->isDot() or !$item->isDir()) {
                continue;
            }
            $pluginname = $item->getFilename();
            if (in_array($pluginname, $ignored)) {
                continue;
            }
            $pluginname = clean_param($pluginname, PARAM_PLUGIN);
            if (empty($pluginname)) {
                // better ignore plugins with problematic names here
                continue;
            }
            $result[$pluginname] = $fulldir.'/'.$pluginname;
            unset($item);
        }
        unset($items);
    }

    //TODO: implement better sorting once we migrated all plugin names to 'pluginname', ksort does not work for unicode, that is why we have to sort by the dir name, not the strings!
    ksort($result);
    return $result;
}

function get_plugin_list_with_file($plugintype, $file, $include = false) {
    global $CFG; // Necessary in case it is referenced by include()d PHP scripts.

    $plugins = array();

    foreach(get_plugin_list($plugintype) as $plugin => $dir) {
        $path = $dir . '/' . $file;
        if (file_exists($path)) {
            if ($include) {
                include_once($path);
            }
            $plugins[$plugin] = $path;
        }
    }

    return $plugins;
}

function get_plugin_list_with_function($plugintype, $function, $file = 'lib.php') {
    $pluginfunctions = array();
    foreach (get_plugin_list_with_file($plugintype, $file, true) as $plugin => $notused) {
        $fullfunction = $plugintype . '_' . $plugin . '_' . $function;

        if (function_exists($fullfunction)) {
            // Function exists with standard name. Store, indexed by
            // frankenstyle name of plugin
            $pluginfunctions[$plugintype . '_' . $plugin] = $fullfunction;

        } else if ($plugintype === 'mod') {
            // For modules, we also allow plugin without full frankenstyle
            // but just starting with the module name
            $shortfunction = $plugin . '_' . $function;
            if (function_exists($shortfunction)) {
                $pluginfunctions[$plugintype . '_' . $plugin] = $shortfunction;
            }
        }
    }
    return $pluginfunctions;
}

function get_plugin_list_with_class($plugintype, $class, $file) {
    if ($class) {
        $suffix = '_' . $class;
    } else {
        $suffix = '';
    }

    $pluginclasses = array();
    foreach (get_plugin_list_with_file($plugintype, $file, true) as $plugin => $notused) {
        $classname = $plugintype . '_' . $plugin . $suffix;
        if (class_exists($classname)) {
            $pluginclasses[$plugintype . '_' . $plugin] = $classname;
        }
    }

    return $pluginclasses;
}

function get_list_of_plugins($directory='mod', $exclude='', $basedir='') {
    global $CFG;

    $plugins = array();

    if (empty($basedir)) {
        $basedir = $CFG->dirroot .'/'. $directory;

    } else {
        $basedir = $basedir .'/'. $directory;
    }

    if (file_exists($basedir) && filetype($basedir) == 'dir') {
        $dirhandle = opendir($basedir);
        while (false !== ($dir = readdir($dirhandle))) {
            $firstchar = substr($dir, 0, 1);
            if ($firstchar === '.' or $dir === 'CVS' or $dir === '_vti_cnf' or $dir === 'simpletest' or $dir === 'yui' or $dir === 'phpunit' or $dir === $exclude) {
                continue;
            }
            if (filetype($basedir .'/'. $dir) != 'dir') {
                continue;
            }
            $plugins[] = $dir;
        }
        closedir($dirhandle);
    }
    if ($plugins) {
        asort($plugins);
    }
    return $plugins;
}

function plugin_callback($type, $name, $feature, $action, $params = null, $default = null) {
    return component_callback($type . '_' . $name, $feature . '_' . $action, (array) $params, $default);
}

function component_callback($component, $function, array $params = array(), $default = null) {
    global $CFG; // this is needed for require_once() below

    $cleancomponent = clean_param($component, PARAM_COMPONENT);
    if (empty($cleancomponent)) {
        throw new coding_exception('Invalid component used in plugin/component_callback():' . $component);
    }
    $component = $cleancomponent;

    list($type, $name) = normalize_component($component);
    $component = $type . '_' . $name;

    $oldfunction = $name.'_'.$function;
    $function = $component.'_'.$function;

    $dir = get_component_directory($component);
    if (empty($dir)) {
        throw new coding_exception('Invalid component used in plugin/component_callback():' . $component);
    }

    // Load library and look for function
    if (file_exists($dir.'/lib.php')) {
        require_once($dir.'/lib.php');
    }

    if (!function_exists($function) and function_exists($oldfunction)) {
        if ($type !== 'mod' and $type !== 'core') {
            debugging("Please use new function name $function instead of legacy $oldfunction");
        }
        $function = $oldfunction;
    }

    if (function_exists($function)) {
        // Function exists, so just return function result
        $ret = call_user_func_array($function, $params);
        if (is_null($ret)) {
            return $default;
        } else {
            return $ret;
        }
    }
    return $default;
}

function plugin_supports($type, $name, $feature, $default = NULL) {
    global $CFG;

    if ($type === 'mod' and $name === 'NEWMODULE') {
        //somebody forgot to rename the module template
        return false;
    }

    $component = clean_param($type . '_' . $name, PARAM_COMPONENT);
    if (empty($component)) {
        throw new coding_exception('Invalid component used in plugin_supports():' . $type . '_' . $name);
    }

    $function = null;

    if ($type === 'mod') {
        // we need this special case because we support subplugins in modules,
        // otherwise it would end up in infinite loop
        if (file_exists("$CFG->dirroot/mod/$name/lib.php")) {
            include_once("$CFG->dirroot/mod/$name/lib.php");
            $function = $component.'_supports';
            if (!function_exists($function)) {
                // legacy non-frankenstyle function name
                $function = $name.'_supports';
            }
        } else {
            // invalid module
        }

    } else {
        if (!$path = get_plugin_directory($type, $name)) {
            // non existent plugin type
            return false;
        }
        if (file_exists("$path/lib.php")) {
            include_once("$path/lib.php");
            $function = $component.'_supports';
        }
    }

    if ($function and function_exists($function)) {
        $supports = $function($feature);
        if (is_null($supports)) {
            // plugin does not know - use default
            return $default;
        } else {
            return $supports;
        }
    }

    //plugin does not care, so use default
    return $default;
}

function check_php_version($version='5.2.4') {
    return (version_compare(phpversion(), $version) >= 0);
}

 function check_browser_operating_system($brand) {
    if (empty($_SERVER['HTTP_USER_AGENT'])) {
        return false;
    }

    if (preg_match("/$brand/i", $_SERVER['HTTP_USER_AGENT'])) {
        return true;
    }

    return false;
 }

 function check_browser_version($brand, $version = null) {
    if (empty($_SERVER['HTTP_USER_AGENT'])) {
        return false;
    }

    $agent = $_SERVER['HTTP_USER_AGENT'];

    switch ($brand) {

      case 'Camino':   
          if (strpos($agent, 'Camino') === false) {
              return false;
          }
          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/Camino\/([0-9\.]+)/i", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'Firefox':   
          if (strpos($agent, 'Iceweasel') === false and strpos($agent, 'Firefox') === false) {
              return false;
          }
          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/(Iceweasel|Firefox)\/([0-9\.]+)/i", $agent, $match)) {
              if (version_compare($match[2], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'Gecko':   
          if (empty($version) and substr_count($agent, 'Camino')) {
              // MacOS X Camino support
              $version = 20041110;
          }

          // the proper string - Gecko/CCYYMMDD Vendor/Version
          // Faster version and work-a-round No IDN problem.
          if (preg_match("/Gecko\/([0-9]+)/i", $agent, $match)) {
              if ($match[1] > $version) {
                      return true;
                  }
              }
          break;


      case 'MSIE':   
          if (strpos($agent, 'Opera') !== false) {     // Reject Opera
              return false;
          }
          // in case of IE we have to deal with BC of the version parameter
          if (is_null($version)) {
              $version = 5.5; // anything older is not considered a browser at all!
          }

          //see: http://www.useragentstring.com/pages/Internet%20Explorer/
          if (preg_match("/MSIE ([0-9\.]+)/", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'Opera':  
          if (strpos($agent, 'Opera') === false) {
              return false;
          }
          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/Opera\/([0-9\.]+)/i", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'WebKit':  
          if (strpos($agent, 'AppleWebKit') === false) {
              return false;
          }
          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/AppleWebKit\/([0-9]+)/i", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'Safari':  
          if (strpos($agent, 'AppleWebKit') === false) {
              return false;
          }
          // Look for AppleWebKit, excluding strings with OmniWeb, Shiira and SymbianOS and any other mobile devices
          if (strpos($agent, 'OmniWeb')) { // Reject OmniWeb
              return false;
          }
          if (strpos($agent, 'Shiira')) { // Reject Shiira
              return false;
          }
          if (strpos($agent, 'SymbianOS')) { // Reject SymbianOS
              return false;
          }
          if (strpos($agent, 'Android')) { // Reject Androids too
              return false;
          }
          if (strpos($agent, 'iPhone') or strpos($agent, 'iPad') or strpos($agent, 'iPod')) {
              // No Apple mobile devices here - editor does not work, course ajax is not touch compatible, etc.
              return false;
          }
          if (strpos($agent, 'Chrome')) { // Reject chrome browsers - it needs to be tested explicitly
              return false;
          }

          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/AppleWebKit\/([0-9]+)/i", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'Chrome':
          if (strpos($agent, 'Chrome') === false) {
              return false;
          }
          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/Chrome\/(.*)[ ]+/i", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'Safari iOS':  
          if (strpos($agent, 'AppleWebKit') === false or strpos($agent, 'Safari') === false) {
              return false;
          }
          if (!strpos($agent, 'iPhone') and !strpos($agent, 'iPad') and !strpos($agent, 'iPod')) {
              return false;
          }
          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/AppleWebKit\/([0-9]+)/i", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;


      case 'WebKit Android':  
          if (strpos($agent, 'Linux; U; Android') === false) {
              return false;
          }
          if (empty($version)) {
              return true; // no version specified
          }
          if (preg_match("/AppleWebKit\/([0-9]+)/i", $agent, $match)) {
              if (version_compare($match[1], $version) >= 0) {
                  return true;
              }
          }
          break;

    }

    return false;
}

function get_device_type() {
    global $CFG;

    if (empty($CFG->enabledevicedetection) || empty($_SERVER['HTTP_USER_AGENT'])) {
        return 'default';
    }

    $useragent = $_SERVER['HTTP_USER_AGENT'];

    if (!empty($CFG->devicedetectregex)) {
        $regexes = json_decode($CFG->devicedetectregex);

        foreach ($regexes as $value=>$regex) {
            if (preg_match($regex, $useragent)) {
                return $value;
            }
        }
    }

    //mobile detection PHP direct copy from open source detectmobilebrowser.com
    $phonesregex = '/android|avantgo|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i';
    $modelsregex = '/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|e\-|e\/|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(di|rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|xda(\-|2|g)|yas\-|your|zeto|zte\-/i';
    if (preg_match($phonesregex,$useragent) || preg_match($modelsregex,substr($useragent, 0, 4))){
        return 'mobile';
    }

    $tabletregex = '/Tablet browser|iPad|iProd|GT-P1000|GT-I9000|SHW-M180S|SGH-T849|SCH-I800|Build\/ERE27|sholest/i';
    if (preg_match($tabletregex, $useragent)) {
         return 'tablet';
    }

    // Safe way to check for IE6 and not get false positives for some IE 7/8 users
    if (substr($_SERVER['HTTP_USER_AGENT'], 0, 34) === 'Mozilla/4.0 (compatible; MSIE 6.0;') {
        return 'legacy';
    }

    return 'default';
}

function get_device_type_list($incusertypes = true) {
    global $CFG;

    $types = array('default', 'legacy', 'mobile', 'tablet');

    if ($incusertypes && !empty($CFG->devicedetectregex)) {
        $regexes = json_decode($CFG->devicedetectregex);

        foreach ($regexes as $value => $regex) {
            $types[] = $value;
        }
    }

    return $types;
}

function get_selected_theme_for_device_type($devicetype = null) {
    global $CFG;

    if (empty($devicetype)) {
        $devicetype = get_user_device_type();
    }

    $themevarname = get_device_cfg_var_name($devicetype);
    if (empty($CFG->$themevarname)) {
        return false;
    }

    return $CFG->$themevarname;
}

function get_device_cfg_var_name($devicetype = null) {
    if ($devicetype == 'default' || empty($devicetype)) {
        return 'theme';
    }

    return 'theme' . $devicetype;
}

function set_user_device_type($newdevice) {
    global $USER;

    $devicetype = get_device_type();
    $devicetypes = get_device_type_list();

    if ($newdevice == $devicetype) {
        unset_user_preference('switchdevice'.$devicetype);
    } else if (in_array($newdevice, $devicetypes)) {
        set_user_preference('switchdevice'.$devicetype, $newdevice);
    }
}

function get_user_device_type() {
    $device = get_device_type();
    $switched = get_user_preferences('switchdevice'.$device, false);
    if ($switched != false) {
        return $switched;
    }
    return $device;
}

function get_browser_version_classes() {
    $classes = array();

    if (check_browser_version("MSIE", "0")) {
        $classes[] = 'ie';
        if (check_browser_version("MSIE", 9)) {
            $classes[] = 'ie9';
        } else if (check_browser_version("MSIE", 8)) {
            $classes[] = 'ie8';
        } elseif (check_browser_version("MSIE", 7)) {
            $classes[] = 'ie7';
        } elseif (check_browser_version("MSIE", 6)) {
            $classes[] = 'ie6';
        }

    } else if (check_browser_version("Firefox") || check_browser_version("Gecko") || check_browser_version("Camino")) {
        $classes[] = 'gecko';
        if (preg_match('/rv\:([1-2])\.([0-9])/', $_SERVER['HTTP_USER_AGENT'], $matches)) {
            $classes[] = "gecko{$matches[1]}{$matches[2]}";
        }

    } else if (check_browser_version("WebKit")) {
        $classes[] = 'safari';
        if (check_browser_version("Safari iOS")) {
            $classes[] = 'ios';

        } else if (check_browser_version("WebKit Android")) {
            $classes[] = 'android';
        }

    } else if (check_browser_version("Opera")) {
        $classes[] = 'opera';

    }

    return $classes;
}

function can_use_rotated_text() {
    global $USER;
    return ajaxenabled(array('Firefox' => 2.0)) && !$USER->screenreader;;
}

function check_gd_version() {
    $gdversion = 0;

    if (function_exists('gd_info')){
        $gd_info = gd_info();
        if (substr_count($gd_info['GD Version'], '2.')) {
            $gdversion = 2;
        } else if (substr_count($gd_info['GD Version'], '1.')) {
            $gdversion = 1;
        }

    } else {
        ob_start();
        phpinfo(INFO_MODULES);
        $phpinfo = ob_get_contents();
        ob_end_clean();

        $phpinfo = explode("\n", $phpinfo);


        foreach ($phpinfo as $text) {
            $parts = explode('</td>', $text);
            foreach ($parts as $key => $val) {
                $parts[$key] = trim(strip_tags($val));
            }
            if ($parts[0] == 'GD Version') {
                if (substr_count($parts[1], '2.0')) {
                    $parts[1] = '2.0';
                }
                $gdversion = intval($parts[1]);
            }
        }
    }

    return $gdversion;   // 1, 2 or 0
}

function moodle_needs_upgrading() {
    global $CFG, $DB, $OUTPUT;

    if (empty($CFG->version)) {
        return true;
    }

    // main versio nfirst
    $version = null;
    include($CFG->dirroot.'/version.php');  // defines $version and upgrades
    if ($version > $CFG->version) {
        return true;
    }

    // modules
    $mods = get_plugin_list('mod');
    $installed = $DB->get_records('modules', array(), '', 'name, version');
    foreach ($mods as $mod => $fullmod) {
        if ($mod === 'NEWMODULE') {   // Someone has unzipped the template, ignore it
            continue;
        }
        $module = new stdClass();
        if (!is_readable($fullmod.'/version.php')) {
            continue;
        }
        include($fullmod.'/version.php');  // defines $module with version etc
        if (empty($installed[$mod])) {
            return true;
        } else if ($module->version > $installed[$mod]->version) {
            return true;
        }
    }
    unset($installed);

    // blocks
    $blocks = get_plugin_list('block');
    $installed = $DB->get_records('block', array(), '', 'name, version');
    require_once($CFG->dirroot.'/blocks/moodleblock.class.php');
    foreach ($blocks as $blockname=>$fullblock) {
        if ($blockname === 'NEWBLOCK') {   // Someone has unzipped the template, ignore it
            continue;
        }
        if (!is_readable($fullblock.'/version.php')) {
            continue;
        }
        $plugin = new stdClass();
        $plugin->version = NULL;
        include($fullblock.'/version.php');
        if (empty($installed[$blockname])) {
            return true;
        } else if ($plugin->version > $installed[$blockname]->version) {
            return true;
        }
    }
    unset($installed);

    // now the rest of plugins
    $plugintypes = get_plugin_types();
    unset($plugintypes['mod']);
    unset($plugintypes['block']);
    foreach ($plugintypes as $type=>$unused) {
        $plugs = get_plugin_list($type);
        foreach ($plugs as $plug=>$fullplug) {
            $component = $type.'_'.$plug;
            if (!is_readable($fullplug.'/version.php')) {
                continue;
            }
            $plugin = new stdClass();
            include($fullplug.'/version.php');  // defines $plugin with version etc
            $installedversion = get_config($component, 'version');
            if (empty($installedversion)) { // new installation
                return true;
            } else if ($installedversion < $plugin->version) { // upgrade
                return true;
            }
        }
    }

    return false;
}

function upgrade_set_timeout($max_execution_time=300) {
    global $CFG;

    if (!isset($CFG->upgraderunning) or $CFG->upgraderunning < time()) {
        $upgraderunning = get_config(null, 'upgraderunning');
    } else {
        $upgraderunning = $CFG->upgraderunning;
    }

    if (!$upgraderunning) {
        // upgrade not running or aborted
        print_error('upgradetimedout', 'admin', "$CFG->wwwroot/$CFG->admin/");
        die;
    }

    if ($max_execution_time < 60) {
        // protection against 0 here
        $max_execution_time = 60;
    }

    $expected_end = time() + $max_execution_time;

    if ($expected_end < $upgraderunning + 10 and $expected_end > $upgraderunning - 10) {
        // no need to store new end, it is nearly the same ;-)
        return;
    }

    set_time_limit($max_execution_time);
    set_config('upgraderunning', $expected_end); // keep upgrade locked until this time
}


function moodle_setlocale($locale='') {
    global $CFG;

    static $currentlocale = ''; // last locale caching

    $oldlocale = $currentlocale;

    if ($CFG->ostype == 'WINDOWS') {
        $stringtofetch = 'localewin';
    } else {
        $stringtofetch = 'locale';
    }

    if (!empty($locale)) {
        $currentlocale = $locale;
    } else if (!empty($CFG->locale)) { // override locale for all language packs
        $currentlocale = $CFG->locale;
    } else {
        $currentlocale = get_string($stringtofetch, 'langconfig');
    }

    if ($oldlocale == $currentlocale) {
        return;
    }


    $monetary= setlocale (LC_MONETARY, 0);
    $numeric = setlocale (LC_NUMERIC, 0);
    $ctype   = setlocale (LC_CTYPE, 0);
    if ($CFG->ostype != 'WINDOWS') {
        $messages= setlocale (LC_MESSAGES, 0);
    }
    setlocale (LC_ALL, $currentlocale);
    setlocale (LC_MONETARY, $monetary);
    setlocale (LC_NUMERIC, $numeric);
    if ($CFG->ostype != 'WINDOWS') {
        setlocale (LC_MESSAGES, $messages);
    }
    if ($currentlocale == 'tr_TR' or $currentlocale == 'tr_TR.UTF-8') { // To workaround a well-known PHP problem with Turkish letter Ii
        setlocale (LC_CTYPE, $ctype);
    }
}

function moodle_strtolower ($string, $encoding='') {

    //If not specified use utf8
    if (empty($encoding)) {
        $encoding = 'UTF-8';
    }
    //Use text services
    $textlib = textlib_get_instance();

    return $textlib->strtolower($string, $encoding);
}

function count_words($string) {
    $string = strip_tags($string);
    return count(preg_split("/\w\b/", $string)) - 1;
}

function count_letters($string) {
    $textlib = textlib_get_instance();

    $string = strip_tags($string); // Tags are out now
    $string = preg_replace('/[[:space:]]*/','',$string); //Whitespace are out now

    return $textlib->strlen($string);
}

function random_string ($length=15) {
    $pool  = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $pool .= 'abcdefghijklmnopqrstuvwxyz';
    $pool .= '0123456789';
    $poollen = strlen($pool);
    mt_srand ((double) microtime() * 1000000);
    $string = '';
    for ($i = 0; $i < $length; $i++) {
        $string .= substr($pool, (mt_rand()%($poollen)), 1);
    }
    return $string;
}

function complex_random_string($length=null) {
    $pool  = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    $pool .= '`~!@#%^&*()_+-=[];,./<>?:{} ';
    $poollen = strlen($pool);
    mt_srand ((double) microtime() * 1000000);
    if ($length===null) {
        $length = floor(rand(24,32));
    }
    $string = '';
    for ($i = 0; $i < $length; $i++) {
        $string .= $pool[(mt_rand()%$poollen)];
    }
    return $string;
}

function shorten_text($text, $ideal=30, $exact = false, $ending='...') {

    global $CFG;

    // if the plain text is shorter than the maximum length, return the whole text
    if (strlen(preg_replace('/<.*?>/', '', $text)) <= $ideal) {
        return $text;
    }

    // Splits on HTML tags. Each open/close/empty tag will be the first thing
    // and only tag in its 'line'
    preg_match_all('/(<.+?>)?([^<>]*)/s', $text, $lines, PREG_SET_ORDER);

    $total_length = strlen($ending);
    $truncate = '';

    // This array stores information about open and close tags and their position
    // in the truncated string. Each item in the array is an object with fields
    // ->open (true if open), ->tag (tag name in lower case), and ->pos
    // (byte position in truncated text)
    $tagdetails = array();

    foreach ($lines as $line_matchings) {
        // if there is any html-tag in this line, handle it and add it (uncounted) to the output
        if (!empty($line_matchings[1])) {
            // if it's an "empty element" with or without xhtml-conform closing slash (f.e. <br/>)
            if (preg_match('/^<(\s*.+?\/\s*|\s*(img|br|input|hr|area|base|basefont|col|frame|isindex|link|meta|param)(\s.+?)?)>$/is', $line_matchings[1])) {
                    // do nothing
            // if tag is a closing tag (f.e. </b>)
            } else if (preg_match('/^<\s*\/([^\s]+?)\s*>$/s', $line_matchings[1], $tag_matchings)) {
                // record closing tag
                $tagdetails[] = (object)array('open'=>false,
                    'tag'=>strtolower($tag_matchings[1]), 'pos'=>strlen($truncate));
            // if tag is an opening tag (f.e. <b>)
            } else if (preg_match('/^<\s*([^\s>!]+).*?>$/s', $line_matchings[1], $tag_matchings)) {
                // record opening tag
                $tagdetails[] = (object)array('open'=>true,
                    'tag'=>strtolower($tag_matchings[1]), 'pos'=>strlen($truncate));
            }
            // add html-tag to $truncate'd text
            $truncate .= $line_matchings[1];
        }

        // calculate the length of the plain text part of the line; handle entities as one character
        $content_length = strlen(preg_replace('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', ' ', $line_matchings[2]));
        if ($total_length+$content_length > $ideal) {
            // the number of characters which are left
            $left = $ideal - $total_length;
            $entities_length = 0;
            // search for html entities
            if (preg_match_all('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', $line_matchings[2], $entities, PREG_OFFSET_CAPTURE)) {
                // calculate the real length of all entities in the legal range
                foreach ($entities[0] as $entity) {
                    if ($entity[1]+1-$entities_length <= $left) {
                        $left--;
                        $entities_length += strlen($entity[0]);
                    } else {
                        // no more characters left
                        break;
                    }
                }
            }
            $truncate .= substr($line_matchings[2], 0, $left+$entities_length);
            // maximum length is reached, so get off the loop
            break;
        } else {
            $truncate .= $line_matchings[2];
            $total_length += $content_length;
        }

        // if the maximum length is reached, get off the loop
        if($total_length >= $ideal) {
            break;
        }
    }

    // if the words shouldn't be cut in the middle...
    if (!$exact) {
        // ...search the last occurence of a space...
        for ($k=strlen($truncate);$k>0;$k--) {
            if (!empty($truncate[$k]) && ($char = $truncate[$k])) {
                if ($char == '.' or $char == ' ') {
                    $breakpos = $k+1;
                    break;
                } else if (ord($char) >= 0xE0) {  // Chinese/Japanese/Korean text
                    $breakpos = $k;               // can be truncated at any UTF-8
                    break;                        // character boundary.
                }
            }
        }

        if (isset($breakpos)) {
            // ...and cut the text in this position
            $truncate = substr($truncate, 0, $breakpos);
        }
    }

    // add the defined ending to the text
    $truncate .= $ending;

    // Now calculate the list of open html tags based on the truncate position
    $open_tags = array();
    foreach ($tagdetails as $taginfo) {
        if(isset($breakpos) && $taginfo->pos >= $breakpos) {
            // Don't include tags after we made the break!
            break;
        }
        if($taginfo->open) {
            // add tag to the beginning of $open_tags list
            array_unshift($open_tags, $taginfo->tag);
        } else {
            $pos = array_search($taginfo->tag, array_reverse($open_tags, true)); // can have multiple exact same open tags, close the last one
            if ($pos !== false) {
                unset($open_tags[$pos]);
            }
        }
    }

    // close all unclosed html-tags
    foreach ($open_tags as $tag) {
        $truncate .= '</' . $tag . '>';
    }

    return $truncate;
}


function getweek ($startdate, $thedate) {
    if ($thedate < $startdate) {   // error
        return 0;
    }

    return floor(($thedate - $startdate) / WEEKSECS) + 1;
}

function generate_password($maxlen=10) {
    global $CFG;

    if (empty($CFG->passwordpolicy)) {
        $fillers = PASSWORD_DIGITS;
        $wordlist = file($CFG->wordlist);
        $word1 = trim($wordlist[rand(0, count($wordlist) - 1)]);
        $word2 = trim($wordlist[rand(0, count($wordlist) - 1)]);
        $filler1 = $fillers[rand(0, strlen($fillers) - 1)];
        $password = $word1 . $filler1 . $word2;
    } else {
        $minlen = !empty($CFG->minpasswordlength) ? $CFG->minpasswordlength : 0;
        $digits = $CFG->minpassworddigits;
        $lower = $CFG->minpasswordlower;
        $upper = $CFG->minpasswordupper;
        $nonalphanum = $CFG->minpasswordnonalphanum;
        $total = $lower + $upper + $digits + $nonalphanum;
        // minlength should be the greater one of the two ( $minlen and $total )
        $minlen = $minlen < $total ? $total : $minlen;
        // maxlen can never be smaller than minlen
        $maxlen = $minlen > $maxlen ? $minlen : $maxlen;
        $additional = $maxlen - $total;

        // Make sure we have enough characters to fulfill
        // complexity requirements
        $passworddigits = PASSWORD_DIGITS;
        while ($digits > strlen($passworddigits)) {
            $passworddigits .= PASSWORD_DIGITS;
        }
        $passwordlower = PASSWORD_LOWER;
        while ($lower > strlen($passwordlower)) {
            $passwordlower .= PASSWORD_LOWER;
        }
        $passwordupper = PASSWORD_UPPER;
        while ($upper > strlen($passwordupper)) {
            $passwordupper .= PASSWORD_UPPER;
        }
        $passwordnonalphanum = PASSWORD_NONALPHANUM;
        while ($nonalphanum > strlen($passwordnonalphanum)) {
            $passwordnonalphanum .= PASSWORD_NONALPHANUM;
        }

        // Now mix and shuffle it all
        $password = str_shuffle (substr(str_shuffle ($passwordlower), 0, $lower) .
                                 substr(str_shuffle ($passwordupper), 0, $upper) .
                                 substr(str_shuffle ($passworddigits), 0, $digits) .
                                 substr(str_shuffle ($passwordnonalphanum), 0 , $nonalphanum) .
                                 substr(str_shuffle ($passwordlower .
                                                     $passwordupper .
                                                     $passworddigits .
                                                     $passwordnonalphanum), 0 , $additional));
    }

    return substr ($password, 0, $maxlen);
}

function format_float($float, $decimalpoints=1, $localized=true) {
    if (is_null($float)) {
        return '';
    }
    if ($localized) {
        return number_format($float, $decimalpoints, get_string('decsep', 'langconfig'), '');
    } else {
        return number_format($float, $decimalpoints, '.', '');
    }
}

function unformat_float($locale_float) {
    $locale_float = trim($locale_float);

    if ($locale_float == '') {
        return null;
    }

    $locale_float = str_replace(' ', '', $locale_float); // no spaces - those might be used as thousand separators

    return (float)str_replace(get_string('decsep', 'langconfig'), '.', $locale_float);
}

function swapshuffle($array) {

    srand ((double) microtime() * 10000000);
    $last = count($array) - 1;
    for ($i=0;$i<=$last;$i++) {
        $from = rand(0,$last);
        $curr = $array[$i];
        $array[$i] = $array[$from];
        $array[$from] = $curr;
    }
    return $array;
}

function swapshuffle_assoc($array) {

    $newarray = array();
    $newkeys = swapshuffle(array_keys($array));

    foreach ($newkeys as $newkey) {
        $newarray[$newkey] = $array[$newkey];
    }
    return $newarray;
}

function draw_rand_array($array, $draws) {
    srand ((double) microtime() * 10000000);

    $return = array();

    $last = count($array);

    if ($draws > $last) {
        $draws = $last;
    }

    while ($draws > 0) {
        $last--;

        $keys = array_keys($array);
        $rand = rand(0, $last);

        $return[$keys[$rand]] = $array[$keys[$rand]];
        unset($array[$keys[$rand]]);

        $draws--;
    }

    return $return;
}

function microtime_diff($a, $b) {
    list($a_dec, $a_sec) = explode(' ', $a);
    list($b_dec, $b_sec) = explode(' ', $b);
    return $b_sec - $a_sec + $b_dec - $a_dec;
}

function make_menu_from_list($list, $separator=',') {

    $array = array_reverse(explode($separator, $list), true);
    foreach ($array as $key => $item) {
        $outarray[$key+1] = trim($item);
    }
    return $outarray;
}

function make_grades_menu($gradingtype) {
    global $DB;

    $grades = array();
    if ($gradingtype < 0) {
        if ($scale = $DB->get_record('scale', array('id'=> (-$gradingtype)))) {
            return make_menu_from_list($scale->scale);
        }
    } else if ($gradingtype > 0) {
        for ($i=$gradingtype; $i>=0; $i--) {
            $grades[$i] = $i .' / '. $gradingtype;
        }
        return $grades;
    }
    return $grades;
}

function course_scale_used($courseid, $scaleid) {
    global $CFG, $DB;

    $return = 0;

    if (!empty($scaleid)) {
        if ($cms = get_course_mods($courseid)) {
            foreach ($cms as $cm) {
                //Check cm->name/lib.php exists
                if (file_exists($CFG->dirroot.'/mod/'.$cm->modname.'/lib.php')) {
                    include_once($CFG->dirroot.'/mod/'.$cm->modname.'/lib.php');
                    $function_name = $cm->modname.'_scale_used';
                    if (function_exists($function_name)) {
                        if ($function_name($cm->instance,$scaleid)) {
                            $return++;
                        }
                    }
                }
            }
        }

        // check if any course grade item makes use of the scale
        $return += $DB->count_records('grade_items', array('courseid'=>$courseid, 'scaleid'=>$scaleid));

        // check if any outcome in the course makes use of the scale
        $return += $DB->count_records_sql("SELECT COUNT('x')
                                             FROM {grade_outcomes_courses} goc,
                                                  {grade_outcomes} go
                                            WHERE go.id = goc.outcomeid
                                                  AND go.scaleid = ? AND goc.courseid = ?",
                                          array($scaleid, $courseid));
    }
    return $return;
}

function site_scale_used($scaleid, &$courses) {
    $return = 0;

    if (!is_array($courses) || count($courses) == 0) {
        $courses = get_courses("all",false,"c.id,c.shortname");
    }

    if (!empty($scaleid)) {
        if (is_array($courses) && count($courses) > 0) {
            foreach ($courses as $course) {
                $return += course_scale_used($course->id,$scaleid);
            }
        }
    }
    return $return;
}

function make_unique_id_code($extra='') {

    $hostname = 'unknownhost';
    if (!empty($_SERVER['HTTP_HOST'])) {
        $hostname = $_SERVER['HTTP_HOST'];
    } else if (!empty($_ENV['HTTP_HOST'])) {
        $hostname = $_ENV['HTTP_HOST'];
    } else if (!empty($_SERVER['SERVER_NAME'])) {
        $hostname = $_SERVER['SERVER_NAME'];
    } else if (!empty($_ENV['SERVER_NAME'])) {
        $hostname = $_ENV['SERVER_NAME'];
    }

    $date = gmdate("ymdHis");

    $random =  random_string(6);

    if ($extra) {
        return $hostname .'+'. $date .'+'. $random .'+'. $extra;
    } else {
        return $hostname .'+'. $date .'+'. $random;
    }
}


function address_in_subnet($addr, $subnetstr) {

    if ($addr == '0.0.0.0') {
        return false;
    }
    $subnets = explode(',', $subnetstr);
    $found = false;
    $addr = trim($addr);
    $addr = cleanremoteaddr($addr, false); // normalise
    if ($addr === null) {
        return false;
    }
    $addrparts = explode(':', $addr);

    $ipv6 = strpos($addr, ':');

    foreach ($subnets as $subnet) {
        $subnet = trim($subnet);
        if ($subnet === '') {
            continue;
        }

        if (strpos($subnet, '/') !== false) {
            list($ip, $mask) = explode('/', $subnet);
            $mask = trim($mask);
            if (!is_number($mask)) {
                continue; // incorect mask number, eh?
            }
            $ip = cleanremoteaddr($ip, false); // normalise
            if ($ip === null) {
                continue;
            }
            if (strpos($ip, ':') !== false) {
                // IPv6
                if (!$ipv6) {
                    continue;
                }
                if ($mask > 128 or $mask < 0) {
                    continue; // nonsense
                }
                if ($mask == 0) {
                    return true; // any address
                }
                if ($mask == 128) {
                    if ($ip === $addr) {
                        return true;
                    }
                    continue;
                }
                $ipparts = explode(':', $ip);
                $modulo  = $mask % 16;
                $ipnet   = array_slice($ipparts, 0, ($mask-$modulo)/16);
                $addrnet = array_slice($addrparts, 0, ($mask-$modulo)/16);
                if (implode(':', $ipnet) === implode(':', $addrnet)) {
                    if ($modulo == 0) {
                        return true;
                    }
                    $pos     = ($mask-$modulo)/16;
                    $ipnet   = hexdec($ipparts[$pos]);
                    $addrnet = hexdec($addrparts[$pos]);
                    $mask    = 0xffff << (16 - $modulo);
                    if (($addrnet & $mask) == ($ipnet & $mask)) {
                        return true;
                    }
                }

            } else {
                // IPv4
                if ($ipv6) {
                    continue;
                }
                if ($mask > 32 or $mask < 0) {
                    continue; // nonsense
                }
                if ($mask == 0) {
                    return true;
                }
                if ($mask == 32) {
                    if ($ip === $addr) {
                        return true;
                    }
                    continue;
                }
                $mask = 0xffffffff << (32 - $mask);
                if (((ip2long($addr) & $mask) == (ip2long($ip) & $mask))) {
                    return true;
                }
            }

        } else if (strpos($subnet, '-') !== false)  {
            $parts = explode('-', $subnet);
            if (count($parts) != 2) {
                continue;
            }

            if (strpos($subnet, ':') !== false) {
                // IPv6
                if (!$ipv6) {
                    continue;
                }
                $ipstart = cleanremoteaddr(trim($parts[0]), false); // normalise
                if ($ipstart === null) {
                    continue;
                }
                $ipparts = explode(':', $ipstart);
                $start = hexdec(array_pop($ipparts));
                $ipparts[] = trim($parts[1]);
                $ipend = cleanremoteaddr(implode(':', $ipparts), false); // normalise
                if ($ipend === null) {
                    continue;
                }
                $ipparts[7] = '';
                $ipnet = implode(':', $ipparts);
                if (strpos($addr, $ipnet) !== 0) {
                    continue;
                }
                $ipparts = explode(':', $ipend);
                $end = hexdec($ipparts[7]);

                $addrend = hexdec($addrparts[7]);

                if (($addrend >= $start) and ($addrend <= $end)) {
                    return true;
                }

            } else {
                // IPv4
                if ($ipv6) {
                    continue;
                }
                $ipstart = cleanremoteaddr(trim($parts[0]), false); // normalise
                if ($ipstart === null) {
                    continue;
                }
                $ipparts = explode('.', $ipstart);
                $ipparts[3] = trim($parts[1]);
                $ipend = cleanremoteaddr(implode('.', $ipparts), false); // normalise
                if ($ipend === null) {
                    continue;
                }

                if ((ip2long($addr) >= ip2long($ipstart)) and (ip2long($addr) <= ip2long($ipend))) {
                    return true;
                }
            }

        } else {
            if (strpos($subnet, ':') !== false) {
                // IPv6
                if (!$ipv6) {
                    continue;
                }
                $parts = explode(':', $subnet);
                $count = count($parts);
                if ($parts[$count-1] === '') {
                    unset($parts[$count-1]); // trim trailing :
                    $count--;
                    $subnet = implode('.', $parts);
                }
                $isip = cleanremoteaddr($subnet, false); // normalise
                if ($isip !== null) {
                    if ($isip === $addr) {
                        return true;
                    }
                    continue;
                } else if ($count > 8) {
                    continue;
                }
                $zeros = array_fill(0, 8-$count, '0');
                $subnet = $subnet.':'.implode(':', $zeros).'/'.($count*16);
                if (address_in_subnet($addr, $subnet)) {
                    return true;
                }

            } else {
                // IPv4
                if ($ipv6) {
                    continue;
                }
                $parts = explode('.', $subnet);
                $count = count($parts);
                if ($parts[$count-1] === '') {
                    unset($parts[$count-1]); // trim trailing .
                    $count--;
                    $subnet = implode('.', $parts);
                }
                if ($count == 4) {
                    $subnet = cleanremoteaddr($subnet, false); // normalise
                    if ($subnet === $addr) {
                        return true;
                    }
                    continue;
                } else if ($count > 4) {
                    continue;
                }
                $zeros = array_fill(0, 4-$count, '0');
                $subnet = $subnet.'.'.implode('.', $zeros).'/'.($count*8);
                if (address_in_subnet($addr, $subnet)) {
                    return true;
                }
            }
        }
    }

    return false;
}

function mtrace($string, $eol="\n", $sleep=0) {

    if (defined('STDOUT')) {
        fwrite(STDOUT, $string.$eol);
    } else {
        echo $string . $eol;
    }

    flush();

    //delay to keep message on user's screen in case of subsequent redirect
    if ($sleep) {
        sleep($sleep);
    }
}

function cleardoubleslashes ($path) {
    return preg_replace('/(\/|\\\){1,}/','/',$path);
}

function remoteip_in_list($list){
    $inlist = false;
    $client_ip = getremoteaddr(null);

    if(!$client_ip){
        // ensure access on cli
        return true;
    }

    $list = explode("\n", $list);
    foreach($list as $subnet) {
        $subnet = trim($subnet);
        if (address_in_subnet($client_ip, $subnet)) {
            $inlist = true;
            break;
        }
    }
    return $inlist;
}

function getremoteaddr($default='0.0.0.0') {
    global $CFG;

    if (empty($CFG->getremoteaddrconf)) {
        // This will happen, for example, before just after the upgrade, as the
        // user is redirected to the admin screen.
        $variablestoskip = 0;
    } else {
        $variablestoskip = $CFG->getremoteaddrconf;
    }
    if (!($variablestoskip & GETREMOTEADDR_SKIP_HTTP_CLIENT_IP)) {
        if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
            $address = cleanremoteaddr($_SERVER['HTTP_CLIENT_IP']);
            return $address ? $address : $default;
        }
    }
    if (!($variablestoskip & GETREMOTEADDR_SKIP_HTTP_X_FORWARDED_FOR)) {
        if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
            $address = cleanremoteaddr($_SERVER['HTTP_X_FORWARDED_FOR']);
            return $address ? $address : $default;
        }
    }
    if (!empty($_SERVER['REMOTE_ADDR'])) {
        $address = cleanremoteaddr($_SERVER['REMOTE_ADDR']);
        return $address ? $address : $default;
    } else {
        return $default;
    }
}

function cleanremoteaddr($addr, $compress=false) {
    $addr = trim($addr);

    //TODO: maybe add a separate function is_addr_public() or something like this

    if (strpos($addr, ':') !== false) {
        // can be only IPv6
        $parts = explode(':', $addr);
        $count = count($parts);

        if (strpos($parts[$count-1], '.') !== false) {
            //legacy ipv4 notation
            $last = array_pop($parts);
            $ipv4 = cleanremoteaddr($last, true);
            if ($ipv4 === null) {
                return null;
            }
            $bits = explode('.', $ipv4);
            $parts[] = dechex($bits[0]).dechex($bits[1]);
            $parts[] = dechex($bits[2]).dechex($bits[3]);
            $count = count($parts);
            $addr = implode(':', $parts);
        }

        if ($count < 3 or $count > 8) {
            return null; // severly malformed
        }

        if ($count != 8) {
            if (strpos($addr, '::') === false) {
                return null; // malformed
            }
            // uncompress ::
            $insertat = array_search('', $parts, true);
            $missing = array_fill(0, 1 + 8 - $count, '0');
            array_splice($parts, $insertat, 1, $missing);
            foreach ($parts as $key=>$part) {
                if ($part === '') {
                    $parts[$key] = '0';
                }
            }
        }

        $adr = implode(':', $parts);
        if (!preg_match('/^([0-9a-f]{1,4})(:[0-9a-f]{1,4})*$/i', $adr)) {
            return null; // incorrect format - sorry
        }

        // normalise 0s and case
        $parts = array_map('hexdec', $parts);
        $parts = array_map('dechex', $parts);

        $result = implode(':', $parts);

        if (!$compress) {
            return $result;
        }

        if ($result === '0:0:0:0:0:0:0:0') {
            return '::'; // all addresses
        }

        $compressed = preg_replace('/(:0)+:0$/', '::', $result, 1);
        if ($compressed !== $result) {
            return $compressed;
        }

        $compressed = preg_replace('/^(0:){2,7}/', '::', $result, 1);
        if ($compressed !== $result) {
            return $compressed;
        }

        $compressed = preg_replace('/(:0){2,6}:/', '::', $result, 1);
        if ($compressed !== $result) {
            return $compressed;
        }

        return $result;
    }

    // first get all things that look like IPv4 addresses
    $parts = array();
    if (!preg_match('/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/', $addr, $parts)) {
        return null;
    }
    unset($parts[0]);

    foreach ($parts as $key=>$match) {
        if ($match > 255) {
            return null;
        }
        $parts[$key] = (int)$match; // normalise 0s
    }

    return implode('.', $parts);
}

function fullclone($thing) {
    return unserialize(serialize($thing));
}


function moodle_request_shutdown() {
    global $CFG;

    // help apache server if possible
    $apachereleasemem = false;
    if (function_exists('apache_child_terminate') && function_exists('memory_get_usage')
            && ini_get_bool('child_terminate')) {

        $limit = (empty($CFG->apachemaxmem) ? 64*1024*1024 : $CFG->apachemaxmem); //64MB default
        if (memory_get_usage() > get_real_size($limit)) {
            $apachereleasemem = $limit;
            @apache_child_terminate();
        }
    }

    // deal with perf logging
    if (defined('MDL_PERF') || (!empty($CFG->perfdebug) and $CFG->perfdebug > 7)) {
        if ($apachereleasemem) {
            error_log('Mem usage over '.$apachereleasemem.': marking Apache child for reaping.');
        }
        if (defined('MDL_PERFTOLOG')) {
            $perf = get_performance_info();
            error_log("PERF: " . $perf['txt']);
        }
        if (defined('MDL_PERFINC')) {
            $inc = get_included_files();
            $ts  = 0;
            foreach($inc as $f) {
                if (preg_match(':^/:', $f)) {
                    $fs  =  filesize($f);
                    $ts  += $fs;
                    $hfs =  display_size($fs);
                    error_log(substr($f,strlen($CFG->dirroot)) . " size: $fs ($hfs)"
                              , NULL, NULL, 0);
                } else {
                    error_log($f , NULL, NULL, 0);
                }
            }
            if ($ts > 0 ) {
                $hts = display_size($ts);
                error_log("Total size of files included: $ts ($hts)");
            }
        }
    }
}

function message_popup_window() {
    global $USER, $DB, $PAGE, $CFG, $SITE;

    if (!$PAGE->get_popup_notification_allowed() || empty($CFG->messaging)) {
        return;
    }

    if (!isloggedin() || isguestuser()) {
        return;
    }

    if (!isset($USER->message_lastpopup)) {
        $USER->message_lastpopup = 0;
    } else if ($USER->message_lastpopup > (time()-120)) {
        //dont run the query to check whether to display a popup if its been run in the last 2 minutes
        return;
    }

    //a quick query to check whether the user has new messages
    $messagecount = $DB->count_records('message', array('useridto' => $USER->id));
    if ($messagecount<1) {
        return;
    }

    //got unread messages so now do another query that joins with the user table
    $messagesql = "SELECT m.id, m.smallmessage, m.fullmessageformat, m.notification, u.firstname, u.lastname
                     FROM {message} m
                     JOIN {message_working} mw ON m.id=mw.unreadmessageid
                     JOIN {message_processors} p ON mw.processorid=p.id
                     JOIN {user} u ON m.useridfrom=u.id
                    WHERE m.useridto = :userid
                      AND p.name='popup'";

    //if the user was last notified over an hour ago we can renotify them of old messages
    //so don't worry about when the new message was sent
    $lastnotifiedlongago = $USER->message_lastpopup < (time()-3600);
    if (!$lastnotifiedlongago) {
        $messagesql .= 'AND m.timecreated > :lastpopuptime';
    }

    $message_users = $DB->get_records_sql($messagesql, array('userid'=>$USER->id, 'lastpopuptime'=>$USER->message_lastpopup));

    //if we have new messages to notify the user about
    if (!empty($message_users)) {

        $strmessages = '';
        if (count($message_users)>1) {
            $strmessages = get_string('unreadnewmessages', 'message', count($message_users));
        } else {
            $message_users = reset($message_users);

            //show who the message is from if its not a notification
            if (!$message_users->notification) {
                $strmessages = get_string('unreadnewmessage', 'message', fullname($message_users) );
            }

            //try to display the small version of the message
            $smallmessage = null;
            if (!empty($message_users->smallmessage)) {
                //display the first 200 chars of the message in the popup
                $textlib = textlib_get_instance();
                $smallmessage = null;
                if ($textlib->strlen($message_users->smallmessage) > 200) {
                    $smallmessage = $textlib->substr($message_users->smallmessage,0,200).'...';
                } else {
                    $smallmessage = $message_users->smallmessage;
                }

                //prevent html symbols being displayed
                if ($message_users->fullmessageformat == FORMAT_HTML) {
                    $smallmessage = html_to_text($smallmessage);
                } else {
                    $smallmessage = s($smallmessage);
                }
            } else if ($message_users->notification) {
                //its a notification with no smallmessage so just say they have a notification
                $smallmessage = get_string('unreadnewnotification', 'message');
            }
            if (!empty($smallmessage)) {
                $strmessages .= '<div id="usermessage">'.s($smallmessage).'</div>';
            }
        }

        $strgomessage = get_string('gotomessages', 'message');
        $strstaymessage = get_string('ignore','admin');

        $url = $CFG->wwwroot.'/message/index.php';
        $content =  html_writer::start_tag('div', array('id'=>'newmessageoverlay','class'=>'mdl-align')).
                        html_writer::start_tag('div', array('id'=>'newmessagetext')).
                            $strmessages.
                        html_writer::end_tag('div').

                        html_writer::start_tag('div', array('id'=>'newmessagelinks')).
                            html_writer::link($url, $strgomessage, array('id'=>'notificationyes')).'&nbsp;&nbsp;&nbsp;'.
                            html_writer::link('', $strstaymessage, array('id'=>'notificationno')).
                        html_writer::end_tag('div');
                    html_writer::end_tag('div');

        $PAGE->requires->js_init_call('M.core_message.init_notification', array('', $content, $url));

        $USER->message_lastpopup = time();
    }
}

function bounded_number($min, $value, $max) {
    if($value < $min) {
        return $min;
    }
    if($value > $max) {
        return $max;
    }
    return $value;
}

function array_is_nested($array) {
    foreach ($array as $value) {
        if (is_array($value)) {
            return true;
        }
    }
    return false;
}

function get_performance_info() {
    global $CFG, $PERF, $DB, $PAGE;

    $info = array();
    $info['html'] = '';         // holds userfriendly HTML representation
    $info['txt']  = me() . ' '; // holds log-friendly representation

    $info['realtime'] = microtime_diff($PERF->starttime, microtime());

    $info['html'] .= '<span class="timeused">'.$info['realtime'].' secs</span> ';
    $info['txt'] .= 'time: '.$info['realtime'].'s ';

    if (function_exists('memory_get_usage')) {
        $info['memory_total'] = memory_get_usage();
        $info['memory_growth'] = memory_get_usage() - $PERF->startmemory;
        $info['html'] .= '<span class="memoryused">RAM: '.display_size($info['memory_total']).'</span> ';
        $info['txt']  .= 'memory_total: '.$info['memory_total'].'B (' . display_size($info['memory_total']).') memory_growth: '.$info['memory_growth'].'B ('.display_size($info['memory_growth']).') ';
    }

    if (function_exists('memory_get_peak_usage')) {
        $info['memory_peak'] = memory_get_peak_usage();
        $info['html'] .= '<span class="memoryused">RAM peak: '.display_size($info['memory_peak']).'</span> ';
        $info['txt']  .= 'memory_peak: '.$info['memory_peak'].'B (' . display_size($info['memory_peak']).') ';
    }

    $inc = get_included_files();
    //error_log(print_r($inc,1));
    $info['includecount'] = count($inc);
    $info['html'] .= '<span class="included">Included '.$info['includecount'].' files</span> ';
    $info['txt']  .= 'includecount: '.$info['includecount'].' ';

    $filtermanager = filter_manager::instance();
    if (method_exists($filtermanager, 'get_performance_summary')) {
        list($filterinfo, $nicenames) = $filtermanager->get_performance_summary();
        $info = array_merge($filterinfo, $info);
        foreach ($filterinfo as $key => $value) {
            $info['html'] .= "<span class='$key'>$nicenames[$key]: $value </span> ";
            $info['txt'] .= "$key: $value ";
        }
    }

    $stringmanager = get_string_manager();
    if (method_exists($stringmanager, 'get_performance_summary')) {
        list($filterinfo, $nicenames) = $stringmanager->get_performance_summary();
        $info = array_merge($filterinfo, $info);
        foreach ($filterinfo as $key => $value) {
            $info['html'] .= "<span class='$key'>$nicenames[$key]: $value </span> ";
            $info['txt'] .= "$key: $value ";
        }
    }

     $jsmodules = $PAGE->requires->get_loaded_modules();
     if ($jsmodules) {
         $yuicount = 0;
         $othercount = 0;
         $details = '';
         foreach ($jsmodules as $module => $backtraces) {
             if (strpos($module, 'yui') === 0) {
                 $yuicount += 1;
             } else {
                 $othercount += 1;
             }
             $details .= "<div class='yui-module'><p>$module</p>";
             foreach ($backtraces as $backtrace) {
                 $details .= "<div class='backtrace'>$backtrace</div>";
             }
             $details .= '</div>';
         }
         $info['html'] .= "<span class='includedyuimodules'>Included YUI modules: $yuicount</span> ";
         $info['txt'] .= "includedyuimodules: $yuicount ";
         $info['html'] .= "<span class='includedjsmodules'>Other JavaScript modules: $othercount</span> ";
         $info['txt'] .= "includedjsmodules: $othercount ";
         // Slightly odd to output the details in a display: none div. The point
         // Is that it takes a lot of space, and if you care you can reveal it
         // using firebug.
         $info['html'] .= '<div id="yui-module-debug" class="notifytiny">'.$details.'</div>';
     }

    if (!empty($PERF->logwrites)) {
        $info['logwrites'] = $PERF->logwrites;
        $info['html'] .= '<span class="logwrites">Log DB writes '.$info['logwrites'].'</span> ';
        $info['txt'] .= 'logwrites: '.$info['logwrites'].' ';
    }

    $info['dbqueries'] = $DB->perf_get_reads().'/'.($DB->perf_get_writes() - $PERF->logwrites);
    $info['html'] .= '<span class="dbqueries">DB reads/writes: '.$info['dbqueries'].'</span> ';
    $info['txt'] .= 'db reads/writes: '.$info['dbqueries'].' ';

    if (function_exists('posix_times')) {
        $ptimes = posix_times();
        if (is_array($ptimes)) {
            foreach ($ptimes as $key => $val) {
                $info[$key] = $ptimes[$key] -  $PERF->startposixtimes[$key];
            }
            $info['html'] .= "<span class=\"posixtimes\">ticks: $info[ticks] user: $info[utime] sys: $info[stime] cuser: $info[cutime] csys: $info[cstime]</span> ";
            $info['txt'] .= "ticks: $info[ticks] user: $info[utime] sys: $info[stime] cuser: $info[cutime] csys: $info[cstime] ";
        }
    }

    // Grab the load average for the last minute
    // /proc will only work under some linux configurations
    // while uptime is there under MacOSX/Darwin and other unices
    if (is_readable('/proc/loadavg') && $loadavg = @file('/proc/loadavg')) {
        list($server_load) = explode(' ', $loadavg[0]);
        unset($loadavg);
    } else if ( function_exists('is_executable') && is_executable('/usr/bin/uptime') && $loadavg = `/usr/bin/uptime` ) {
        if (preg_match('/load averages?: (\d+[\.,:]\d+)/', $loadavg, $matches)) {
            $server_load = $matches[1];
        } else {
            trigger_error('Could not parse uptime output!');
        }
    }
    if (!empty($server_load)) {
        $info['serverload'] = $server_load;
        $info['html'] .= '<span class="serverload">Load average: '.$info['serverload'].'</span> ';
        $info['txt'] .= "serverload: {$info['serverload']} ";
    }

    // Display size of session if session started
    if (session_id()) {
        $info['sessionsize'] = display_size(strlen(session_encode()));
        $info['html'] .= '<span class="sessionsize">Session: ' . $info['sessionsize'] . '</span> ';
        $info['txt'] .= "Session: {$info['sessionsize']} ";
    }

/*    if (isset($rcache->hits) && isset($rcache->misses)) {
        $info['rcachehits'] = $rcache->hits;
        $info['rcachemisses'] = $rcache->misses;
        $info['html'] .= '<span class="rcache">Record cache hit/miss ratio : '.
            "{$rcache->hits}/{$rcache->misses}</span> ";
        $info['txt'] .= 'rcache: '.
            "{$rcache->hits}/{$rcache->misses} ";
    }*/
    $info['html'] = '<div class="performanceinfo siteinfo">'.$info['html'].'</div>';
    return $info;
}

function apd_get_profiling() {
    return shell_exec('pprofp -u ' . ini_get('apd.dumpdir') . '/pprof.' . getmypid() . '.*');
}

function remove_dir($dir, $content_only=false) {
    if (!file_exists($dir)) {
        // nothing to do
        return true;
    }
    $handle = opendir($dir);
    $result = true;
    while (false!==($item = readdir($handle))) {
        if($item != '.' && $item != '..') {
            if(is_dir($dir.'/'.$item)) {
                $result = remove_dir($dir.'/'.$item) && $result;
            }else{
                $result = unlink($dir.'/'.$item) && $result;
            }
        }
    }
    closedir($handle);
    if ($content_only) {
        clearstatcache(); // make sure file stat cache is properly invalidated
        return $result;
    }
    $result = rmdir($dir); // if anything left the result will be false, no need for && $result
    clearstatcache(); // make sure file stat cache is properly invalidated
    return $result;
}

function object_property_exists( $obj, $property ) {
    if (is_string( $obj )) {
        $properties = get_class_vars( $obj );
    }
    else {
        $properties = get_object_vars( $obj );
    }
    return array_key_exists( $property, $properties );
}


function custom_script_path() {
    global $CFG, $SCRIPT;

    if ($SCRIPT === null) {
        // Probably some weird external script
        return false;
    }

    $scriptpath = $CFG->customscripts . $SCRIPT;

    // check the custom script exists
    if (file_exists($scriptpath) and is_file($scriptpath)) {
        return $scriptpath;
    } else {
        return false;
    }
}

function is_mnet_remote_user($user) {
    global $CFG;

    if (!isset($CFG->mnet_localhost_id)) {
        include_once $CFG->dirroot . '/mnet/lib.php';
        $env = new mnet_environment();
        $env->init();
        unset($env);
    }

    return (!empty($user->mnethostid) && $user->mnethostid != $CFG->mnet_localhost_id);
}

function setup_lang_from_browser() {

    global $CFG, $SESSION, $USER;

    if (!empty($SESSION->lang) or !empty($USER->lang) or empty($CFG->autolang)) {
        // Lang is defined in session or user profile, nothing to do
        return;
    }

    if (!isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) { // There isn't list of browser langs, nothing to do
        return;
    }

    $rawlangs = $_SERVER['HTTP_ACCEPT_LANGUAGE'];
    $rawlangs = str_replace('-', '_', $rawlangs);         // we are using underscores
    $rawlangs = explode(',', $rawlangs);                  // Convert to array
    $langs = array();

    $order = 1.0;
    foreach ($rawlangs as $lang) {
        if (strpos($lang, ';') === false) {
            $langs[(string)$order] = $lang;
            $order = $order-0.01;
        } else {
            $parts = explode(';', $lang);
            $pos = strpos($parts[1], '=');
            $langs[substr($parts[1], $pos+1)] = $parts[0];
        }
    }
    krsort($langs, SORT_NUMERIC);

    foreach ($langs as $lang) {
        $lang = strtolower(clean_param($lang, PARAM_SAFEDIR)); // clean it properly for include
        if (get_string_manager()->translation_exists($lang, false)) {
            $SESSION->lang = $lang; 
            break; 
        }
    }
    return;
}

function is_proxybypass( $url ) {
    global $CFG;

    // sanity check
    if (empty($CFG->proxyhost) or empty($CFG->proxybypass)) {
        return false;
    }

    // get the host part out of the url
    if (!$host = parse_url( $url, PHP_URL_HOST )) {
        return false;
    }

    // get the possible bypass hosts into an array
    $matches = explode( ',', $CFG->proxybypass );

    // check for a match
    // (IPs need to match the left hand side and hosts the right of the url,
    // but we can recklessly check both as there can't be a false +ve)
    $bypass = false;
    foreach ($matches as $match) {
        $match = trim($match);

        // try for IP match (Left side)
        $lhs = substr($host,0,strlen($match));
        if (strcasecmp($match,$lhs)==0) {
            return true;
        }

        // try for host match (Right side)
        $rhs = substr($host,-strlen($match));
        if (strcasecmp($match,$rhs)==0) {
            return true;
        }
    }

    // nothing matched.
    return false;
}



function is_newnav($navigation) {
    if (is_array($navigation) && !empty($navigation['newnav'])) {
        return true;
    } else {
        return false;
    }
}

function in_object_vars($var, $object) {
    $class_vars = get_class_vars(get_class($object));
    $class_vars = array_keys($class_vars);
    return in_array($var, $class_vars);
}

function object_array_unique($array, $keep_key_assoc = true) {
    $duplicate_keys = array();
    $tmp         = array();

    foreach ($array as $key=>$val) {
        // convert objects to arrays, in_array() does not support objects
        if (is_object($val)) {
            $val = (array)$val;
        }

        if (!in_array($val, $tmp)) {
            $tmp[] = $val;
        } else {
            $duplicate_keys[] = $key;
        }
    }

    foreach ($duplicate_keys as $key) {
        unset($array[$key]);
    }

    return $keep_key_assoc ? $array : array_values($array);
}

function is_primary_admin($userid){
    $primaryadmin =  get_admin();

    if($userid == $primaryadmin->id){
        return true;
    }else{
        return false;
    }
}

function get_site_identifier() {
    global $CFG;
    // Check to see if it is missing. If so, initialise it.
    if (empty($CFG->siteidentifier)) {
        set_config('siteidentifier', random_string(32) . $_SERVER['HTTP_HOST']);
    }
    // Return it.
    return $CFG->siteidentifier;
}

function check_consecutive_identical_characters($password, $maxchars) {

    if ($maxchars < 1) {
        return true; // 0 is to disable this check
    }
    if (strlen($password) <= $maxchars) {
        return true; // too short to fail this test
    }

    $previouschar = '';
    $consecutivecount = 1;
    foreach (str_split($password) as $char) {
        if ($char != $previouschar) {
            $consecutivecount = 1;
        }
        else {
            $consecutivecount++;
            if ($consecutivecount > $maxchars) {
                return false; // check failed already
            }
        }

        $previouschar = $char;
    }

    return true;
}

function partial() {
    if (!class_exists('partial')) {
        class partial{
            var $values = array();
            var $func;

            function __construct($func, $args) {
                $this->values = $args;
                $this->func = $func;
            }

            function method() {
                $args = func_get_args();
                return call_user_func_array($this->func, array_merge($this->values, $args));
            }
        }
    }
    $args = func_get_args();
    $func = array_shift($args);
    $p = new partial($func, $args);
    return array($p, 'method');
}

function get_mnet_environment() {
    global $CFG;
    require_once($CFG->dirroot . '/mnet/lib.php');
    static $instance = null;
    if (empty($instance)) {
        $instance = new mnet_environment();
        $instance->init();
    }
    return $instance;
}

function get_mnet_remote_client() {
    if (!defined('MNET_SERVER')) {
        debugging(get_string('notinxmlrpcserver', 'mnet'));
        return false;
    }
    global $MNET_REMOTE_CLIENT;
    if (isset($MNET_REMOTE_CLIENT)) {
        return $MNET_REMOTE_CLIENT;
    }
    return false;
}

function set_mnet_remote_client($client) {
    if (!defined('MNET_SERVER')) {
        throw new moodle_exception('notinxmlrpcserver', 'mnet');
    }
    global $MNET_REMOTE_CLIENT;
    $MNET_REMOTE_CLIENT = $client;
}

function mnet_get_idp_jump_url($user) {
    global $CFG;

    static $mnetjumps = array();
    if (!array_key_exists($user->mnethostid, $mnetjumps)) {
        $idp = mnet_get_peer_host($user->mnethostid);
        $idpjumppath = mnet_get_app_jumppath($idp->applicationid);
        $mnetjumps[$user->mnethostid] = $idp->wwwroot . $idpjumppath . '?hostwwwroot=' . $CFG->wwwroot . '&wantsurl=';
    }
    return $mnetjumps[$user->mnethostid];
}

function get_home_page() {
    global $CFG;

    if (isloggedin() && !isguestuser() && !empty($CFG->defaulthomepage)) {
        if ($CFG->defaulthomepage == HOMEPAGE_MY) {
            return HOMEPAGE_MY;
        } else {
            return (int)get_user_preferences('user_home_page_preference', HOMEPAGE_MY);
        }
    }
    return HOMEPAGE_SITE;
}