$';

/**
 * Allowed protocols - array of protocols that are safe to use in links and so on
 * @global string $ALLOWED_PROTOCOLS
 */
$ALLOWED_PROTOCOLS = array('http', 'https', 'ftp', 'news', 'mailto', 'rtsp', 'teamspeak', 'gopher', 'mms',
                           'color', 'callto', 'cursor', 'text-align', 'font-size', 'font-weight', 'font-style', 'font-family',
                           'border', 'margin', 'padding', 'background', 'background-color', 'text-decoration');   // CSS as well to get through kses


/// Functions

/**
 * Add quotes to HTML characters
 *
 * Returns $var with HTML characters (like "<", ">", etc.) properly quoted.
 * This function is very similar to {@link p()}
 *
 * @param string $var the string potentially containing HTML characters
 * @param boolean $strip to decide if we want to strip slashes or no. Default to false.
 *                true should be used to print data from forms and false for data from DB.
 * @return string
 */
function s($var, $strip=false) {

    if ($var == '0') {  // for integer 0, boolean false, string '0'
        return '0';
    }

    if ($strip) {
        return preg_replace("/&(#\d+);/i", "&$1;", htmlspecialchars($var));
    } else {
        return preg_replace("/&(#\d+);/i", "&$1;", htmlspecialchars($var));
    }
}

/**
 * Add quotes to HTML characters
 *
 * Prints $var with HTML characters (like "<", ">", etc.) properly quoted.
 * This function is very similar to {@link s()}
 *
 * @param string $var the string potentially containing HTML characters
 * @param boolean $strip to decide if we want to strip slashes or no. Default to false.
 *                true should be used to print data from forms and false for data from DB.
 * @return string
 */
function p($var, $strip=false) {
    echo s($var, $strip);
}

/**
 * Does proper javascript quoting.
 * Do not use addslashes anymore, because it does not work when magic_quotes_sybase is enabled.
 *
 * @since 1.8 - 22/02/2007
 * @param mixed value
 * @return mixed quoted result
 */
function addslashes_js($var) {
    if (is_string($var)) {
        $var = str_replace('\\', '\\\\', $var);
        $var = str_replace(array('\'', '"', "\n", "\r", "\0"), array('\\\'', '\\"', '\\n', '\\r', '\\0'), $var);
        $var = str_replace('$value) {
          $a[$key] = addslashes_js($value);
        }
        $var = (object)$a;
    }
    return $var;
}

/**
 * Remove query string from url
 *
 * Takes in a URL and returns it without the querystring portion
 *
 * @param string $url the url which may have a query string attached
 * @return string
 */
 function strip_querystring($url) {

    if ($commapos = strpos($url, '?')) {
        return substr($url, 0, $commapos);
    } else {
        return $url;
    }
}

/**
 * Returns the URL of the HTTP_REFERER, less the querystring portion if required
 * @param boolean $stripquery if true, also removes the query part of the url.
 * @return string
 */
function get_referer($stripquery=true) {
    if (isset($_SERVER['HTTP_REFERER'])) {
        if ($stripquery) {
            return strip_querystring($_SERVER['HTTP_REFERER']);
        } else {
            return $_SERVER['HTTP_REFERER'];
        }
    } else {
        return '';
    }
}


/**
 * Returns the name of the current script, WITH the querystring portion.
 * this function is necessary because PHP_SELF and REQUEST_URI and SCRIPT_NAME
 * return different things depending on a lot of things like your OS, Web
 * server, and the way PHP is compiled (ie. as a CGI, module, ISAPI, etc.)
 * NOTE: This function returns false if the global variables needed are not set.
 *
 * @return string
 */
 function me() {

    if (!empty($_SERVER['REQUEST_URI'])) {
        return $_SERVER['REQUEST_URI'];

    } else if (!empty($_SERVER['PHP_SELF'])) {
        if (!empty($_SERVER['QUERY_STRING'])) {
            return $_SERVER['PHP_SELF'] .'?'. $_SERVER['QUERY_STRING'];
        }
        return $_SERVER['PHP_SELF'];

    } else if (!empty($_SERVER['SCRIPT_NAME'])) {
        if (!empty($_SERVER['QUERY_STRING'])) {
            return $_SERVER['SCRIPT_NAME'] .'?'. $_SERVER['QUERY_STRING'];
        }
        return $_SERVER['SCRIPT_NAME'];

    } else if (!empty($_SERVER['URL'])) {     // May help IIS (not well tested)
        if (!empty($_SERVER['QUERY_STRING'])) {
            return $_SERVER['URL'] .'?'. $_SERVER['QUERY_STRING'];
        }
        return $_SERVER['URL'];

    } else {
        notify('Warning: Could not find any of these web server variables: $REQUEST_URI, $PHP_SELF, $SCRIPT_NAME or $URL');
        return false;
    }
}

/**
 * Like {@link me()} but returns a full URL
 * @see me()
 * @return string
 */
function qualified_me() {

    global $CFG;

    if (!empty($CFG->wwwroot)) {
        $url = parse_url($CFG->wwwroot);
    }

    if (!empty($url['host'])) {
        $hostname = $url['host'];
    } else if (!empty($_SERVER['SERVER_NAME'])) {
        $hostname = $_SERVER['SERVER_NAME'];
    } else if (!empty($_ENV['SERVER_NAME'])) {
        $hostname = $_ENV['SERVER_NAME'];
    } else if (!empty($_SERVER['HTTP_HOST'])) {
        $hostname = $_SERVER['HTTP_HOST'];
    } else if (!empty($_ENV['HTTP_HOST'])) {
        $hostname = $_ENV['HTTP_HOST'];
    } else {
        notify('Warning: could not find the name of this server!');
        return false;
    }

    if (!empty($url['port'])) {
        $hostname .= ':'.$url['port'];
    } else if (!empty($_SERVER['SERVER_PORT'])) {
        if ($_SERVER['SERVER_PORT'] != 80 && $_SERVER['SERVER_PORT'] != 443) {
            $hostname .= ':'.$_SERVER['SERVER_PORT'];
        }
    }

    // TODO, this does not work in the situation described in MDL-11061, but
    // I don't know how to fix it. Possibly believe $CFG->wwwroot ahead of what
    // the server reports.
    if (isset($_SERVER['HTTPS'])) {
        $protocol = ($_SERVER['HTTPS'] == 'on') ? 'https://' : 'http://';
    } else if (isset($_SERVER['SERVER_PORT'])) { # Apache2 does not export $_SERVER['HTTPS']
        $protocol = ($_SERVER['SERVER_PORT'] == '443') ? 'https://' : 'http://';
    } else {
        $protocol = 'http://';
    }

    $url_prefix = $protocol.$hostname;
    return $url_prefix . me();
}


/**
 * Class for creating and manipulating urls.
 *
 * See short write up here http://docs.moodle.org/en/Development:lib/weblib.php_moodle_url
 */
class moodle_url {
    var $scheme = '';// e.g. http
    var $host = '';
    var $port = '';
    var $user = '';
    var $pass = '';
    var $path = '';
    var $fragment = '';
    var $params = array(); //associative array of query string params

    /**
     * Pass no arguments to create a url that refers to this page. Use empty string to create empty url.
     *
     * @param string $url url default null means use this page url with no query string
     *                      empty string means empty url.
     *                      if you pass any other type of url it will be parsed into it's bits, including query string
     * @param array $params these params override anything in the query string where params have the same name.
     */
    function moodle_url($url = null, $params = array()){
        global $FULLME;
        if ($url !== ''){
            if ($url === null){
                $url = strip_querystring($FULLME);
            }
            $parts = parse_url($url);
            if ($parts === FALSE){
                print_error('invalidurl');
            }
            if (isset($parts['query'])){
                parse_str(str_replace('&', '&', $parts['query']), $this->params);
            }
            unset($parts['query']);
            foreach ($parts as $key => $value){
                $this->$key = $value;
            }
            $this->params($params);
        }
    }
    /**
     * Add an array of params to the params for this page. The added params override existing ones if they
     * have the same name.
     *
     * @param array $params  Defaults to null. If null then return value of
     * param 'name'.
     * @return array params for url.
     */
    function params($params = null){
        if (!is_null($params)){
            return $this->params = $params + $this->params;
        } else {
            return $this->params;
        }
    }

    /**
     * Remove all params if no arguments passed. Or else remove param $arg1, $arg2, etc.
     *
     * @param string $arg1
     * @param string $arg2
     * @param string $arg3
     */
    function remove_params(){
        if ($thisargs = func_get_args()){
            foreach ($thisargs as $arg){
                if (isset($this->params[$arg])){
                    unset($this->params[$arg]);
                }
            }
        } else { // no args
            $this->params = array();
        }
    }

    /**
     * Add a param to the params for this page. The added param overrides existing one if they
     * have the same name.
     *
     * @param string $paramname name
     * @param string $param value. Defaults to null. If null then return value
     * of param 'name'
     */
    function param($paramname, $param = null){
        if (!is_null($param)){
            $this->params = array($paramname => $param) + $this->params;
        } else {
            return $this->params[$paramname];
        }
    }


    function get_query_string($overrideparams = array()){
        $arr = array();
        $params = $overrideparams + $this->params;
        foreach ($params as $key => $val){
           $arr[] = urlencode($key)."=".urlencode($val);
        }
        return implode($arr, "&");
    }
    /**
     * Outputs params as hidden form elements.
     *
     * @param  array $exclude params to ignore
     * @param integer $indent indentation
     * @param array $overrideparams params to add to the output params, these
     * override existing ones with the same name.
     * @return string html for form elements.
     */
    function hidden_params_out($exclude = array(), $indent = 0, $overrideparams=array()){
        $tabindent = str_repeat("\t", $indent);
        $str = '';
        $params = $overrideparams + $this->params;
        foreach ($params as $key => $val){
            if (FALSE === array_search($key, $exclude)) {
                $val = s($val);
                $str.= "$tabindent\n";
            }
        }
        return $str;
    }
    /**
     * Output url
     *
     * @param boolean $noquerystring whether to output page params as a query string in the url.
     * @param array $overrideparams params to add to the output url, these override existing ones with the same name.
     * @return string url
     */
    function out($noquerystring = false, $overrideparams = array()) {
        $uri = $this->scheme ? $this->scheme.':'.((strtolower($this->scheme) == 'mailto') ? '':'//'): '';
        $uri .= $this->user ? $this->user.($this->pass? ':'.$this->pass:'').'@':'';
        $uri .= $this->host ? $this->host : '';
        $uri .= $this->port ? ':'.$this->port : '';
        $uri .= $this->path ? $this->path : '';
        if (!$noquerystring){
            $uri .= (count($this->params)||count($overrideparams)) ? '?'.$this->get_query_string($overrideparams) : '';
        }
        $uri .= $this->fragment ? '#'.$this->fragment : '';
        return $uri;
    }
    /**
     * Output action url with sesskey
     *
     * @param boolean $noquerystring whether to output page params as a query string in the url.
     * @return string url
     */
    function out_action($overrideparams = array()) {
        $overrideparams = array('sesskey'=> sesskey()) + $overrideparams;
        return $this->out(false, $overrideparams);
    }
}

/**
 * Determine if there is data waiting to be processed from a form
 *
 * Used on most forms in Moodle to check for data
 * Returns the data as an object, if it's found.
 * This object can be used in foreach loops without
 * casting because it's cast to (array) automatically
 *
 * Checks that submitted POST data exists and returns it as object.
 *
 * @return mixed false or object
 */
function data_submitted() {

    if (empty($_POST)) {
        return false;
    } else {
        return (object)$_POST;
    }
}

/**
 * Given some normal text this function will break up any
 * long words to a given size by inserting the given character
 *
 * It's multibyte savvy and doesn't change anything inside html tags.
 *
 * @param string $string the string to be modified
 * @param int $maxsize maximum length of the string to be returned
 * @param string $cutchar the string used to represent word breaks
 * @return string
 */
function break_up_long_words($string, $maxsize=20, $cutchar=' ') {

/// Loading the textlib singleton instance. We are going to need it.
    $textlib = textlib_get_instance();

/// First of all, save all the tags inside the text to skip them
    $tags = array();
    filter_save_tags($string,$tags);

/// Process the string adding the cut when necessary
    $output = '';
    $length = $textlib->strlen($string);
    $wordlength = 0;

    for ($i=0; $i<$length; $i++) {
        $char = $textlib->substr($string, $i, 1);
        if ($char == ' ' or $char == "\t" or $char == "\n" or $char == "\r" or $char == "<" or $char == ">") {
            $wordlength = 0;
        } else {
            $wordlength++;
            if ($wordlength > $maxsize) {
                $output .= $cutchar;
                $wordlength = 0;
            }
        }
        $output .= $char;
    }

/// Finally load the tags back again
    if (!empty($tags)) {
        $output = str_replace(array_keys($tags), $tags, $output);
    }

    return $output;
}

/**
 * This function will print a button/link/etc. form element
 * that will work on both Javascript and non-javascript browsers.
 * Relies on the Javascript function openpopup in javascript.php
 *
 * All parameters default to null, only $type and $url are mandatory.
 *
 * $url must be relative to home page  eg /mod/survey/stuff.php
 * @param string $url Web link. Either relative to $CFG->wwwroot, or a full URL.
 * @param string $name Name to be assigned to the popup window (this is used by
 *   client-side scripts to "talk" to the popup window)
 * @param string $linkname Text to be displayed as web link
 * @param int $height Height to assign to popup window
 * @param int $width Height to assign to popup window
 * @param string $title Text to be displayed as popup page title
 * @param string $options List of additional options for popup window
 * @param string $return If true, return as a string, otherwise print
 * @param string $id id added to the element
 * @param string $class class added to the element
 * @return string
 * @uses $CFG
 */
function element_to_popup_window ($type=null, $url=null, $name=null, $linkname=null,
                                  $height=400, $width=500, $title=null,
                                  $options=null, $return=false, $id=null, $class=null) {

    if (is_null($url)) {
        debugging('You must give the url to display in the popup. URL is missing - can\'t create popup window.', DEBUG_DEVELOPER);
    }

    global $CFG;

    if ($options == 'none') { // 'none' is legacy, should be removed in v2.0
        $options = null;
    }

    // add some sane default options for popup windows
    if (!$options) {
        $options = 'menubar=0,location=0,scrollbars,resizable';
    }
    if ($width) {
        $options .= ',width='. $width;
    }
    if ($height) {
        $options .= ',height='. $height;
    }
    if ($id) {
        $id = ' id="'.$id.'" ';
    }
    if ($class) {
        $class = ' class="'.$class.'" ';
    }
    if ($name) {
        $_name = $name;
        if (($name = preg_replace("/\s/", '_', $name)) != $_name) {
            debugging('The $name of a popup window shouldn\'t contain spaces - string modified. '. $_name .' changed to '. $name, DEBUG_DEVELOPER);
        }
    } else {
        $name = 'popup';
    }

    // get some default string, using the localized version of legacy defaults
    if (is_null($linkname) || $linkname === '') {
        $linkname = get_string('clickhere');
    }
    if (!$title) {
        $title = get_string('popupwindowname');
    }

    $fullscreen = 0; // must be passed to openpopup
    $element = '';

    switch ($type) {
        case 'button':
            $element = '\n";
            break;
        case 'link':
            // Add wwwroot only if the URL does not already start with http:// or https://
            if (!preg_match('|https?://|', $url)) {
                $url = $CFG->wwwroot . $url;
            }
            $element = '$linkname";
            break;
        default :
            print_error('cannotcreatepopupwin');
            break;
    }

    if ($return) {
        return $element;
    } else {
        echo $element;
    }
}

/**
 * Creates and displays (or returns) a link to a popup window, using element_to_popup_window function.
 *
 * @return string html code to display a link to a popup window.
 * @see element_to_popup_window()
 */
function link_to_popup_window ($url, $name=null, $linkname=null,
                               $height=400, $width=500, $title=null,
                               $options=null, $return=false) {

    return element_to_popup_window('link', $url, $name, $linkname, $height, $width, $title, $options, $return, null, null);
}

/**
 * Creates and displays (or returns) a buttons to a popup window, using element_to_popup_window function.
 *
 * @return string html code to display a button to a popup window.
 * @see element_to_popup_window()
 */
function button_to_popup_window ($url, $name=null, $linkname=null,
                                 $height=400, $width=500, $title=null, $options=null, $return=false,
                                 $id=null, $class=null) {

    return element_to_popup_window('button', $url, $name, $linkname, $height, $width, $title, $options, $return, $id, $class);
}


/**
 * Prints a simple button to close a window
 * @param string $name name of the window to close
 * @param boolean $return whether this function should return a string or output it.
 * @param boolean $reloadopener if true, clicking the button will also reload
 *      the page that opend this popup window.
 * @return string if $return is true, nothing otherwise
 */
function close_window_button($name='closewindow', $return=false, $reloadopener = false) {
    global $CFG;

    $js = 'self.close();';
    if ($reloadopener) {
        $js = 'window.opener.location.reload(1);' . $js;
    }

    $output = '';

    $output .= '' . "\n";
    $output .= '';
    $output .= '';
    $output .= '';
    $output .= '' . "\n";

    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}

/*
 * Try and close the current window immediately using Javascript
 * @param int $delay the delay in seconds before closing the window
 */
function close_window($delay=0) {
?>


 element as an onchange handler.
 * @param string $nothingvalue The value corresponding to the $nothing option. Defaults to 0.
 * @param boolean $return if false (the default) the the output is printed directly, If true, the
 *      generated HTML is returned as a string.
 * @param boolean $disabled if true, the select is generated in a disabled state. Default, false.
 * @param int $tabindex if give, sets the tabindex attribute on the <select> element. Default none.
 * @param string $id value to use for the id attribute of the <select> element. If none is given,
 *      then a suitable one is constructed.
 * @param mixed $listbox if false, display as a dropdown menu. If true, display as a list box.
 *      By default, the list box will have a number of rows equal to min(10, count($options)), but if
 *      $listbox is an integer, that number is used for size instead.
 * @param boolean $multiple if true, enable multiple selections, else only 1 item can be selected. Used
 *      when $listbox display is enabled
 * @param string $class value to use for the class attribute of the <select> element. If none is given,
 *      then a suitable one is constructed.
 */
function choose_from_menu ($options, $name, $selected='', $nothing='choose', $script='',
                           $nothingvalue='0', $return=false, $disabled=false, $tabindex=0,
                           $id='', $listbox=false, $multiple=false, $class='') {

    if ($nothing == 'choose') {
        $nothing = get_string('choose') .'...';
    }

    $attributes = ($script) ? 'onchange="'. $script .'"' : '';
    if ($disabled) {
        $attributes .= ' disabled="disabled"';
    }

    if ($tabindex) {
        $attributes .= ' tabindex="'.$tabindex.'"';
    }

    if ($id ==='') {
        $id = 'menu'.$name;
         // name may contaion [], which would make an invalid id. e.g. numeric question type editing form, assignment quickgrading
        $id = str_replace('[', '', $id);
        $id = str_replace(']', '', $id);
    }

    if ($class ==='') {
        $class = 'menu'.$name;
         // name may contaion [], which would make an invalid class. e.g. numeric question type editing form, assignment quickgrading
        $class = str_replace('[', '', $class);
        $class = str_replace(']', '', $class);
    }
    $class = 'select ' . $class; /// Add 'select' selector always

    if ($listbox) {
        if (is_integer($listbox)) {
            $size = $listbox;
        } else {
            $numchoices = count($options);
            if ($nothing) {
                $numchoices += 1;
            }
            $size = min(10, $numchoices);
        }
        $attributes .= ' size="' . $size . '"';
        if ($multiple) {
            $attributes .= ' multiple="multiple"';
        }
    }

    $output = '' . "\n";
    if ($nothing) {
        $output .= '   ' . "\n";
    }

    if (!empty($options)) {
        foreach ($options as $value => $label) {
            $output .= '   ' . "\n";
            } else {
                $output .= '>'. $label .'' . "\n";
            }
        }
    }
    $output .= '' . "\n";

    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}

/**
 * Choose value 0 or 1 from a menu with options 'No' and 'Yes'.
 * Other options like choose_from_menu.
 * @param string $name
 * @param string $selected
 * @param string $string (defaults to '')
 * @param boolean $return whether this function should return a string or output it (defaults to false)
 * @param boolean $disabled (defaults to false)
 * @param int $tabindex
 */
function choose_from_menu_yesno($name, $selected, $script = '',
        $return = false, $disabled = false, $tabindex = 0) {
    return choose_from_menu(array(get_string('no'), get_string('yes')), $name,
            $selected, '', $script, '0', $return, $disabled, $tabindex);
}

/**
 * Just like choose_from_menu, but takes a nested array (2 levels) and makes a dropdown menu
 * including option headings with the first level.
 */
function choose_from_menu_nested($options,$name,$selected='',$nothing='choose',$script = '',
                                 $nothingvalue=0,$return=false,$disabled=false,$tabindex=0) {

   if ($nothing == 'choose') {
        $nothing = get_string('choose') .'...';
    }

    $attributes = ($script) ? 'onchange="'. $script .'"' : '';
    if ($disabled) {
        $attributes .= ' disabled="disabled"';
    }

    if ($tabindex) {
        $attributes .= ' tabindex="'.$tabindex.'"';
    }

    $output = '' . "\n";
    if ($nothing) {
        $output .= '   ' . "\n";
    }
    if (!empty($options)) {
        foreach ($options as $section => $values) {

            $output .= '   '."\n";
            foreach ($values as $value => $label) {
                $output .= '   ' . "\n";
                } else {
                    $output .= '>'. $label .'' . "\n";
                }
            }
            $output .= '   '."\n";
        }
    }
    $output .= '' . "\n";

    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}


/**
 * Given an array of values, creates a group of radio buttons to be part of a form
 *
 * @param array  $options  An array of value-label pairs for the radio group (values as keys)
 * @param string $name     Name of the radiogroup (unique in the form)
 * @param string $checked  The value that is already checked
 */
function choose_from_radio ($options, $name, $checked='', $return=false) {

    static $idcounter = 0;

    if (!$name) {
        $name = 'unnamed';
    }

    $output = '\n";

    if (!empty($options)) {
        $currentradio = 0;
        foreach ($options as $value => $label) {
            $htmlid = 'auto-rb'.sprintf('%04d', ++$idcounter);
            $output .= ' ";
            $output .= ''.  $value .'' .  "\n";
            } else {
                $output .= ' /> '.  $label .'' .  "\n";
            }
            $currentradio = ($currentradio + 1) % 2;
        }
    }

    $output .= '' .  "\n";

    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}

/** Display an standard html checkbox with an optional label
 *
 * @param string  $name    The name of the checkbox
 * @param string  $value   The valus that the checkbox will pass when checked
 * @param boolean $checked The flag to tell the checkbox initial state
 * @param string  $label   The label to be showed near the checkbox
 * @param string  $alt     The info to be inserted in the alt tag
 */
function print_checkbox ($name, $value, $checked = true, $label = '', $alt = '', $script='',$return=false) {

    static $idcounter = 0;

    if (!$name) {
        $name = 'unnamed';
    }

    if ($alt) {
        $alt = strip_tags($alt);
    } else {
        $alt = 'checkbox';
    }

    if ($checked) {
        $strchecked = ' checked="checked"';
    } else {
        $strchecked = '';
    }

    $htmlid = 'auto-cb'.sprintf('%04d', ++$idcounter);
    $output  = '";
    $output .= '';
    if(!empty($label)) {
        $output .= ' '.$label.'';
    }
    $output .= ''."\n";

    if (empty($return)) {
        echo $output;
    } else {
        return $output;
    }

}

/** Display an standard html text field with an optional label
 *
 * @param string  $name    The name of the text field
 * @param string  $value   The value of the text field
 * @param string  $label   The label to be showed near the text field
 * @param string  $alt     The info to be inserted in the alt tag
 */
function print_textfield ($name, $value, $alt = '',$size=50,$maxlength=0, $return=false) {

    static $idcounter = 0;

    if (empty($name)) {
        $name = 'unnamed';
    }

    if (empty($alt)) {
        $alt = 'textfield';
    }

    if (!empty($maxlength)) {
        $maxlength = ' maxlength="'.$maxlength.'" ';
    }

    $htmlid = 'auto-tf'.sprintf('%04d', ++$idcounter);
    $output  = '";
    $output .= '';

    $output .= ''."\n";

    if (empty($return)) {
        echo $output;
    } else {
        return $output;
    }

}


/**
 * Implements a complete little form with a dropdown menu. When JavaScript is on
 * selecting an option from the dropdown automatically submits the form (while
 * avoiding the usual acessibility problems with this appoach). With JavaScript
 * off, a 'Go' button is printed.
 *
 * @param string $baseurl The target URL up to the point of the variable that changes
 * @param array $options A list of value-label pairs for the popup list
 * @param string $formid id for the control. Must be unique on the page. Used in the HTML.
 * @param string $selected The option that is initially selected
 * @param string $nothing The label for the "no choice" option
 * @param string $help The name of a help page if help is required
 * @param string $helptext The name of the label for the help button
 * @param boolean $return Indicates whether the function should return the HTML
 *         as a string or echo it directly to the page being rendered
 * @param string $targetwindow The name of the target page to open the linked page in.
 * @param string $selectlabel Text to place in a [label] element - preferred for accessibility.
 * @param array $optionsextra an array with the same keys as $options. The values are added within the corresponding  tag.
 * @param string $submitvalue Optional label for the 'Go' button. Defaults to get_string('go').
 * @param boolean $disabled If true, the menu will be displayed disabled.
 * @return string If $return is true then the entire form is returned as a string.
 * @todo Finish documenting this function
 */
function popup_form($baseurl, $options, $formid, $selected='', $nothing='choose', $help='', $helptext='', $return=false,
$targetwindow='self', $selectlabel='', $optionsextra=NULL, $submitvalue='', $disabled=false) {

    global $CFG, $SESSION;
    static $go, $choose;   /// Locally cached, in case there's lots on a page

    if (empty($options)) {
        return '';
    }

    if (empty($submitvalue)){
        if (!isset($go)) {
            $go = get_string('go');
            $submitvalue=$go;
        }
    }
    if ($nothing == 'choose') {
        if (!isset($choose)) {
            $choose = get_string('choose');
        }
        $nothing = $choose.'...';
    }
    if ($disabled) {
        $disabled = 'disabled="disabled"';
    } else {
        $disabled = '';
    }

    // changed reference to document.getElementById('id_abc') instead of document.abc
    // MDL-7861
    $output = 'frametarget.
                        ' id="'.$formid.'"'.
                        ' class="popupform">';
    if ($help) {
        $button = helpbutton($help, $helptext, 'moodle', true, false, '', true);
    } else {
        $button = '';
    }

    if ($selectlabel) {
        $selectlabel = ''.$selectlabel.'';
    }

    //IE and Opera fire the onchange when ever you move into a dropdown list with the keyboard.
    //onfocus will call a function inside dropdown.js. It fixes this IE/Opera behavior.
    //Note: There is a bug on Opera+Linux with the javascript code (first mouse selection is inactive),
    //so we do not fix the Opera behavior on Linux
    if (check_browser_version('MSIE') || (check_browser_version('Opera') && !check_browser_operating_system("Linux"))) {
        $output .= ''.$selectlabel.$button.''."\n";
    }
    //Other browser
    else {
        $output .= ''.$selectlabel.$button.''."\n";
    }

    if ($nothing != '') {
        $selectlabeloption = '';
        if ($selected=='') {
            $selectlabeloption = ' selected="selected"';
        }
        foreach ($options as $value => $label) {  //if one of the options is the empty value, don't make this the default
            if ($value == '') {
                $selected = '';
            }
        }
        $output .= "   $nothing\n";
    }

    $inoptgroup = false;

    foreach ($options as $value => $label) {

        if ($label == '--') { /// we are ending previous optgroup
            /// Check to see if we already have a valid open optgroup
            /// XHTML demands that there be at least 1 option within an optgroup
            if ($inoptgroup and (count($optgr) > 1) ) {
                $output .= implode('', $optgr);
                $output .= '   ';
            }
            $optgr = array();
            $inoptgroup = false;
            continue;
        } else if (substr($label,0,2) == '--') { /// we are starting a new optgroup

            /// Check to see if we already have a valid open optgroup
            /// XHTML demands that there be at least 1 option within an optgroup
            if ($inoptgroup and (count($optgr) > 1) ) {
                $output .= implode('', $optgr);
                $output .= '   ';
            }

            unset($optgr);
            $optgr = array();

            $optgr[]  = '   ';   // Plain labels

            $inoptgroup = true; /// everything following will be in an optgroup
            continue;

        } else {
           if (!empty($CFG->usesid) && !isset($_COOKIE[session_name()]))
            {
                $url = $SESSION->sid_process_url( $baseurl . $value );
            } else
            {
                $url=$baseurl . $value;
            }
            $optstr = '   ' . "\n";
            } else {
                $optstr .= '>'. $value .'' . "\n";
            }

            if ($inoptgroup) {
                $optgr[] = $optstr;
            } else {
                $output .= $optstr;
            }
        }

    }

    /// catch the final group if not closed
    if ($inoptgroup and count($optgr) > 1) {
        $output .= implode('', $optgr);
        $output .= '    ';
    }

    $output .= '';
    $output .= '';
    $output .= '';
    $output .= '';
    $output .= '';
    $output .= '';
    $output .= '';

    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}


/**
 * Prints some red text
 *
 * @param string $error The text to be displayed in red
 */
function formerr($error) {

    if (!empty($error)) {
        echo ''. $error .'';
    }
}

/**
 * Validates an email to make sure it makes sense.
 *
 * @param string $address The email address to validate.
 * @return boolean
 */
function validate_email($address) {

    return (ereg('^[-!#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+'.
                 '(\.[-!#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+)*'.
                  '@'.
                  '[-!#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+\.'.
                  '[-!#$%&\'*+\\./0-9=?A-Z^_`a-z{|}~]+$',
                  $address));
}

/**
 * Extracts file argument either from file parameter or PATH_INFO
 *
 * @param string $scriptname name of the calling script
 * @return string file path (only safe characters)
 */
function get_file_argument($scriptname) {
    global $_SERVER;

    $relativepath = FALSE;

    // first try normal parameter (compatible method == no relative links!)
    $relativepath = optional_param('file', FALSE, PARAM_PATH);
    if ($relativepath === '/testslasharguments') {
        echo 'test -1      : Incorrect use - try "file.php/testslasharguments" instead'; //indicate fopen/fread works for health center
        die;
    }

    // then try extract file from PATH_INFO (slasharguments method)
    if (!$relativepath and !empty($_SERVER['PATH_INFO'])) {
        $path_info = $_SERVER['PATH_INFO'];
        // check that PATH_INFO works == must not contain the script name
        if (!strpos($path_info, $scriptname)) {
            $relativepath = clean_param(rawurldecode($path_info), PARAM_PATH);
            if ($relativepath === '/testslasharguments') {
                echo 'test 1      : Slasharguments test passed. Server confguration is compatible with file.php/1/pic.jpg slashargument setting.'; //indicate ok for health center
                die;
            }
        }
    }

    // now if both fail try the old way
    // (for compatibility with misconfigured or older buggy php implementations)
    if (!$relativepath) {
        $arr = explode($scriptname, me());
        if (!empty($arr[1])) {
            $path_info = strip_querystring($arr[1]);
            $relativepath = clean_param(rawurldecode($path_info), PARAM_PATH);
            if ($relativepath === '/testslasharguments') {
                echo 'test 2      : Slasharguments test passed (compatibility hack). Server confguration may be compatible with file.php/1/pic.jpg slashargument setting'; //indicate ok for health center
                die;
            }
        }
    }

    return $relativepath;
}

/**
 * Searches the current environment variables for some slash arguments
 *
 * @param string $file ?
 * @todo Finish documenting this function
 */
function get_slash_arguments($file='file.php') {

    if (!$string = me()) {
        return false;
    }

    $pathinfo = explode($file, $string);

    if (!empty($pathinfo[1])) {
        return $pathinfo[1];
    } else {
        return false;
    }
}

/**
 * Extracts arguments from "/foo/bar/something"
 * eg http://mysite.com/script.php/foo/bar/something
 *
 * @param string $string ?
 * @param int $i ?
 * @return array|string
 * @todo Finish documenting this function
 */
function parse_slash_arguments($string, $i=0) {

    if (detect_munged_arguments($string)) {
        return false;
    }
    $args = explode('/', $string);

    if ($i) {     // return just the required argument
        return $args[$i];

    } else {      // return the whole array
        array_shift($args);  // get rid of the empty first one
        return $args;
    }
}

/**
 * Just returns an array of text formats suitable for a popup menu
 *
 * @uses FORMAT_MOODLE
 * @uses FORMAT_HTML
 * @uses FORMAT_PLAIN
 * @uses FORMAT_MARKDOWN
 * @return array
 */
function format_text_menu() {

    return array (FORMAT_MOODLE => get_string('formattext'),
                  FORMAT_HTML   => get_string('formathtml'),
                  FORMAT_PLAIN  => get_string('formatplain'),
                  FORMAT_MARKDOWN  => get_string('formatmarkdown'));
}

/**
 * Given text in a variety of format codings, this function returns
 * the text as safe HTML.
 *
 * This function should mainly be used for long strings like posts,
 * answers, glossary items etc. For short strings @see format_string().
 *
 * @uses $CFG
 * @uses FORMAT_MOODLE
 * @uses FORMAT_HTML
 * @uses FORMAT_PLAIN
 * @uses FORMAT_WIKI
 * @uses FORMAT_MARKDOWN
 * @param string $text The text to be formatted. This is raw text originally from user input.
 * @param int $format Identifier of the text format to be used
 *            (FORMAT_MOODLE, FORMAT_HTML, FORMAT_PLAIN, FORMAT_WIKI, FORMAT_MARKDOWN)
 * @param  array $options ?
 * @param int $courseid ?
 * @return string
 * @todo Finish documenting this function
 */
function format_text($text, $format=FORMAT_MOODLE, $options=NULL, $courseid=NULL) {

    global $CFG, $COURSE, $DB;

    static $croncache = array();

    if ($text === '') {
        return ''; // no need to do any filters and cleaning
    }

    if (!isset($options->trusttext)) {
        $options->trusttext = false;
    }

    if (!isset($options->noclean)) {
        $options->noclean=false;
    }
    if (!isset($options->nocache)) {
        $options->nocache=false;
    }
    if (!isset($options->smiley)) {
        $options->smiley=true;
    }
    if (!isset($options->filter)) {
        $options->filter=true;
    }
    if (!isset($options->para)) {
        $options->para=true;
    }
    if (!isset($options->newlines)) {
        $options->newlines=true;
    }

    if (empty($courseid)) {
        $courseid = $COURSE->id;
    }

    if (!empty($CFG->cachetext) and empty($options->nocache)) {
        $time = time() - $CFG->cachetext;
        $md5key = md5($text.'-'.(int)$courseid.'-'.current_language().'-'.(int)$format.(int)$options->trusttext.(int)$options->noclean.(int)$options->smiley.(int)$options->filter.(int)$options->para.(int)$options->newlines);

        if (defined('FULLME') and FULLME == 'cron') {
            if (isset($croncache[$md5key])) {
                return $croncache[$md5key];
            }
        }

        if ($oldcacheitem = $DB->get_record('cache_text', array('md5key'=>$md5key), '*', true)) {
            if ($oldcacheitem->timemodified >= $time) {
                if (defined('FULLME') and FULLME == 'cron') {
                    if (count($croncache) > 150) {
                        reset($croncache);
                        $key = key($croncache);
                        unset($croncache[$key]);
                    }
                    $croncache[$md5key] = $oldcacheitem->formattedtext;
                }
                return $oldcacheitem->formattedtext;
            }
        }
    }

    // trusttext overrides the noclean option!
    if ($options->trusttext) {
        if (trusttext_present($text)) {
            $text = trusttext_strip($text);
            if (!empty($CFG->enabletrusttext)) {
                $options->noclean = true;
            } else {
                $options->noclean = false;
            }
        } else {
            $options->noclean = false;
        }
    } else if (!debugging('', DEBUG_DEVELOPER)) {
        // strip any forgotten trusttext in non-developer mode
        // do not forget to disable text cache when debugging trusttext!!
        $text = trusttext_strip($text);
    }

    $CFG->currenttextiscacheable = true;   // Default status - can be changed by any filter

    switch ($format) {
        case FORMAT_HTML:
            if ($options->smiley) {
                replace_smilies($text);
            }
            if (!$options->noclean) {
                $text = clean_text($text, FORMAT_HTML);
            }
            if ($options->filter) {
                $text = filter_text($text, $courseid);
            }
            break;

        case FORMAT_PLAIN:
            $text = s($text); // cleans dangerous JS
            $text = rebuildnolinktag($text);
            $text = str_replace('  ', '  ', $text);
            $text = nl2br($text);
            break;

        case FORMAT_WIKI:
            // this format is deprecated
            $text = 'NOTICE: Wiki-like formatting has been removed from Moodle.  You should not be seeing
                     this message as all texts should have been converted to Markdown format instead.
                     Please post a bug report to http://moodle.org/bugs with information about where you
                     saw this message.'.s($text);
            break;

        case FORMAT_MARKDOWN:
            $text = markdown_to_html($text);
            if ($options->smiley) {
                replace_smilies($text);
            }
            if (!$options->noclean) {
                $text = clean_text($text, FORMAT_HTML);
            }

            if ($options->filter) {
                $text = filter_text($text, $courseid);
            }
            break;

        default:  // FORMAT_MOODLE or anything else
            $text = text_to_html($text, $options->smiley, $options->para, $options->newlines);
            if (!$options->noclean) {
                $text = clean_text($text, FORMAT_HTML);
            }

            if ($options->filter) {
                $text = filter_text($text, $courseid);
            }
            break;
    }

    if (empty($options->nocache) and !empty($CFG->cachetext) and $CFG->currenttextiscacheable) {
        if (defined('FULLME') and FULLME == 'cron') {
            // special static cron cache - no need to store it in db if its not already there
            if (count($croncache) > 150) {
                reset($croncache);
                $key = key($croncache);
                unset($croncache[$key]);
            }
            $croncache[$md5key] = $text;
            return $text;
        }

        $newcacheitem = new object();
        $newcacheitem->md5key = $md5key;
        $newcacheitem->formattedtext = $text;
        $newcacheitem->timemodified = time();
        if ($oldcacheitem) {                               // See bug 4677 for discussion
            $newcacheitem->id = $oldcacheitem->id;
            @$DB->update_record('cache_text', $newcacheitem);   // Update existing record in the cache table
                                                           // It's unlikely that the cron cache cleaner could have
                                                           // deleted this entry in the meantime, as it allows
                                                           // some extra time to cover these cases.
        } else {
            @$DB->insert_record('cache_text', $newcacheitem);   // Insert a new record in the cache table
                                                           // Again, it's possible that another user has caused this
                                                           // record to be created already in the time that it took
                                                           // to traverse this function.  That's OK too, as the
                                                           // call above handles duplicate entries, and eventually
                                                           // the cron cleaner will delete them.
        }
    }

    return $text;
}

/** Converts the text format from the value to the 'internal'
 *  name or vice versa. $key can either be the value or the name
 *  and you get the other back.
 *
 *  @param mixed int 0-4 or string one of 'moodle','html','plain','markdown'
 *  @return mixed as above but the other way around!
 */
function text_format_name( $key ) {
  $lookup = array();
  $lookup[FORMAT_MOODLE] = 'moodle';
  $lookup[FORMAT_HTML] = 'html';
  $lookup[FORMAT_PLAIN] = 'plain';
  $lookup[FORMAT_MARKDOWN] = 'markdown';
  $value = "error";
  if (!is_numeric($key)) {
    $key = strtolower( $key );
    $value = array_search( $key, $lookup );
  }
  else {
    if (isset( $lookup[$key] )) {
      $value =  $lookup[ $key ];
    }
  }
  return $value;
}

/**
 * Resets all data related to filters, called during upgrade or when filter settings change.
 * @return void
 */
function reset_text_filters_cache() {
    global $CFG, $DB;

    $DB->delete_records('cache_text');
    $purifdir = $CFG->dataroot.'/cache/htmlpurifier';
    remove_dir($purifdir, true);
}

/** Given a simple string, this function returns the string
 *  processed by enabled string filters if $CFG->filterall is enabled
 *
 *  This function should be used to print short strings (non html) that
 *  need filter processing e.g. activity titles, post subjects,
 *  glossary concepts.
 *
 *  @param string  $string     The string to be filtered.
 *  @param boolean $striplinks To strip any link in the result text (Moodle 1.8 default changed from false to true! MDL-8713)
 *  @param int     $courseid   Current course as filters can, potentially, use it
 *  @return string
 */
function format_string ($string, $striplinks=true, $courseid=NULL ) {

    global $CFG, $COURSE;

    //We'll use a in-memory cache here to speed up repeated strings
    static $strcache = false;

    if ($strcache === false or count($strcache) > 2000 ) { // this number might need some tuning to limit memory usage in cron
        $strcache = array();
    }

    //init course id
    if (empty($courseid)) {
        $courseid = $COURSE->id;
    }

    //Calculate md5
    $md5 = md5($string.'<+>'.$striplinks.'<+>'.$courseid.'<+>'.current_language());

    //Fetch from cache if possible
    if (isset($strcache[$md5])) {
        return $strcache[$md5];
    }

    // First replace all ampersands not followed by html entity code
    $string = preg_replace("/\&(?![a-zA-Z0-9#]{1,8};)/", "&", $string);

    if (!empty($CFG->filterall)) {
        $string = filter_string($string, $courseid);
    }

    // If the site requires it, strip ALL tags from this string
    if (!empty($CFG->formatstringstriptags)) {
        $string = strip_tags($string);

    } else {
        // Otherwise strip just links if that is required (default)
        if ($striplinks) {  //strip links in string
            $string = preg_replace('/(]+?>)(.+?)(<\/a>)/is','$2',$string);
        }
        $string = clean_text($string);
    }

    //Store to cache
    $strcache[$md5] = $string;

    return $string;
}

/**
 * Given text in a variety of format codings, this function returns
 * the text as plain text suitable for plain email.
 *
 * @uses FORMAT_MOODLE
 * @uses FORMAT_HTML
 * @uses FORMAT_PLAIN
 * @uses FORMAT_WIKI
 * @uses FORMAT_MARKDOWN
 * @param string $text The text to be formatted. This is raw text originally from user input.
 * @param int $format Identifier of the text format to be used
 *            (FORMAT_MOODLE, FORMAT_HTML, FORMAT_PLAIN, FORMAT_WIKI, FORMAT_MARKDOWN)
 * @return string
 */
function format_text_email($text, $format) {

    switch ($format) {

        case FORMAT_PLAIN:
            return $text;
            break;

        case FORMAT_WIKI:
            $text = wiki_to_html($text);
        /// This expression turns links into something nice in a text format. (Russell Jungwirth)
        /// From: http://php.net/manual/en/function.eregi-replace.php and simplified
            $text = eregi_replace('(]*>([^<]*))','\\3 [ \\2 ]', $text);
            return strtr(strip_tags($text), array_flip(get_html_translation_table(HTML_ENTITIES)));
            break;

        case FORMAT_HTML:
            return html_to_text($text);
            break;

        case FORMAT_MOODLE:
        case FORMAT_MARKDOWN:
        default:
            $text = eregi_replace('(]*>([^<]*))','\\3 [ \\2 ]', $text);
            return strtr(strip_tags($text), array_flip(get_html_translation_table(HTML_ENTITIES)));
            break;
    }
}

/**
 * Given some text in HTML format, this function will pass it
 * through any filters that have been defined in $CFG->textfilterx
 * The variable defines a filepath to a file containing the
 * filter function.  The file must contain a variable called
 * $textfilter_function which contains the name of the function
 * with $courseid and $text parameters
 *
 * @param string $text The text to be passed through format filters
 * @param int $courseid ?
 * @return string
 * @todo Finish documenting this function
 */
function filter_text($text, $courseid=NULL) {
    global $CFG, $COURSE;

    if (empty($courseid)) {
        $courseid = $COURSE->id;       // (copied from format_text)
    }

    if (!empty($CFG->textfilters)) {
        require_once($CFG->libdir.'/filterlib.php');
        $textfilters = explode(',', $CFG->textfilters);
        foreach ($textfilters as $textfilter) {
            if (is_readable($CFG->dirroot .'/'. $textfilter .'/filter.php')) {
                include_once($CFG->dirroot .'/'. $textfilter .'/filter.php');
                $functionname = basename($textfilter).'_filter';
                if (function_exists($functionname)) {
                    $text = $functionname($courseid, $text);
                }
            }
        }
    }

    ///  tags removed for XHTML compatibility
    $text = str_replace('', '', $text);
    $text = str_replace('', '', $text);

    return $text;
}


/**
 * Given a string (short text) in HTML format, this function will pass it
 * through any filters that have been defined in $CFG->stringfilters
 * The variable defines a filepath to a file containing the
 * filter function.  The file must contain a variable called
 * $textfilter_function which contains the name of the function
 * with $courseid and $text parameters
 *
 * @param string $string The text to be passed through format filters
 * @param int $courseid The id of a course
 * @return string
 */
function filter_string($string, $courseid=NULL) {
    global $CFG, $COURSE;

    if (empty($CFG->textfilters)) {             // All filters are disabled anyway so quit
        return $string;
    }

    if (empty($courseid)) {
        $courseid = $COURSE->id;
    }

    require_once($CFG->libdir.'/filterlib.php');

    if (isset($CFG->stringfilters)) {               // We have a predefined list to use, great!
        if (empty($CFG->stringfilters)) {                    // but it's blank, so finish now
            return $string;
        }
        $stringfilters = explode(',', $CFG->stringfilters);  // ..use the list we have

    } else {                                        // Otherwise try to derive a list from textfilters
        if (strpos($CFG->textfilters, 'filter/multilang') !== false) {  // Multilang is here
            $stringfilters = array('filter/multilang');       // Let's use just that
            $CFG->stringfilters = 'filter/multilang';         // Save it for next time through
        } else {
            $CFG->stringfilters = '';                         // Save the result and return
            return $string;
        }
    }


    foreach ($stringfilters as $stringfilter) {
        if (is_readable($CFG->dirroot .'/'. $stringfilter .'/filter.php')) {
            include_once($CFG->dirroot .'/'. $stringfilter .'/filter.php');
            $functionname = basename($stringfilter).'_filter';
            if (function_exists($functionname)) {
                $string = $functionname($courseid, $string);
            }
        }
    }

    ///  tags removed for XHTML compatibility
    $string = str_replace('', '', $string);
    $string = str_replace('', '', $string);

    return $string;
}

/**
 * Is the text marked as trusted?
 *
 * @param string $text text to be searched for TRUSTTEXT marker
 * @return boolean
 */
function trusttext_present($text) {
    if (strpos($text, TRUSTTEXT) !== FALSE) {
        return true;
    } else {
        return false;
    }
}

/**
 * This funtion MUST be called before the cleaning or any other
 * function that modifies the data! We do not know the origin of trusttext
 * in database, if it gets there in tweaked form we must not convert it
 * to supported form!!!
 * @param string $text text that may contain TRUSTTEXT marker
 * @return text without any TRUSTTEXT marker
 */
function trusttext_strip($text) {
    global $CFG;

    while (true) { //removing nested TRUSTTEXT
        $orig = $text;
        $text = str_replace(TRUSTTEXT, '', $text);
        if (strcmp($orig, $text) === 0) {
            return $text;
        }
    }
}

/**
 * Mark text as trusted, such text may contain any HTML tags because the
 * normal text cleaning will be bypassed.
 * Please make sure that the text comes from trusted user before storing
 * it into database!
 */
function trusttext_mark($text) {
    global $CFG;
    if (!empty($CFG->enabletrusttext) and (strpos($text, TRUSTTEXT) === FALSE)) {
        return TRUSTTEXT.$text;
    } else {
        return $text;
    }
}
function trusttext_after_edit(&$text, $context) {
    if (has_capability('moodle/site:trustcontent', $context)) {
        $text = trusttext_strip($text);
        $text = trusttext_mark($text);
    } else {
        $text = trusttext_strip($text);
    }
}

function trusttext_prepare_edit(&$text, &$format, $usehtmleditor, $context) {
    global $CFG;

    $options = new object();
    $options->smiley = false;
    $options->filter = false;
    if (!empty($CFG->enabletrusttext)
         and has_capability('moodle/site:trustcontent', $context)
         and trusttext_present($text)) {
        $options->noclean = true;
    } else {
        $options->noclean = false;
    }
    $text = trusttext_strip($text);
    if ($usehtmleditor) {
        $text = format_text($text, $format, $options);
        $format = FORMAT_HTML;
    } else if (!$options->noclean){
        $text = clean_text($text, $format);
    }
}

/**
 * Given raw text (eg typed in by a user), this function cleans it up
 * and removes any nasty tags that could mess up Moodle pages.
 *
 * @uses FORMAT_MOODLE
 * @uses FORMAT_PLAIN
 * @uses ALLOWED_TAGS
 * @param string $text The text to be cleaned
 * @param int $format Identifier of the text format to be used
 *            (FORMAT_MOODLE, FORMAT_HTML, FORMAT_PLAIN, FORMAT_WIKI, FORMAT_MARKDOWN)
 * @return string The cleaned up text
 */
function clean_text($text, $format=FORMAT_MOODLE) {

    global $ALLOWED_TAGS, $CFG;

    if (empty($text) or is_numeric($text)) {
       return (string)$text;
    }

    switch ($format) {
        case FORMAT_PLAIN:
        case FORMAT_MARKDOWN:
            return $text;

        default:

            if (!empty($CFG->enablehtmlpurifier)) {
                $text = purify_html($text);
            } else {
            /// Fix non standard entity notations
                $text = preg_replace('/(&#[0-9]+)(;?)/', "\\1;", $text);
                $text = preg_replace('/(&#x[0-9a-fA-F]+)(;?)/', "\\1;", $text);

            /// Remove tags that are not allowed
                $text = strip_tags($text, $ALLOWED_TAGS);

            /// Clean up embedded scripts and , using kses
                $text = cleanAttributes($text);

            /// Again remove tags that are not allowed
                $text = strip_tags($text, $ALLOWED_TAGS);

            }

        /// Remove potential script events - some extra protection for undiscovered bugs in our code
            $text = eregi_replace("([^a-z])language([[:space:]]*)=", "\\1Xlanguage=", $text);
            $text = eregi_replace("([^a-z])on([a-z]+)([[:space:]]*)=", "\\1Xon\\2=", $text);

            return $text;
    }
}

/**
 * KSES replacement cleaning function - uses HTML Purifier.
 */
function purify_html($text) {
    global $CFG;

    // this can not be done only once because we sometimes need to reset the cache
    $cachedir = $CFG->dataroot.'/cache/htmlpurifier';
    $status = check_dir_exists($cachedir, true, true);

    static $purifier = false;
    static $config;
    if ($purifier === false) {
        require_once $CFG->libdir.'/htmlpurifier/HTMLPurifier.safe-includes.php';
        $config = HTMLPurifier_Config::createDefault();
        $config->set('Core', 'ConvertDocumentToFragment', true);
        $config->set('Core', 'Encoding', 'UTF-8');
        $config->set('HTML', 'Doctype', 'XHTML 1.0 Transitional');
        $config->set('Cache', 'SerializerPath', $cachedir);
        $config->set('URI', 'AllowedSchemes', array('http'=>1, 'https'=>1, 'ftp'=>1, 'irc'=>1, 'nntp'=>1, 'news'=>1, 'rtsp'=>1, 'teamspeak'=>1, 'gopher'=>1, 'mms'=>1));
        $config->set('Attr', 'AllowedFrameTargets', array('_blank'));
        $purifier = new HTMLPurifier($config);
    }
    return $purifier->purify($text);
}

/**
 * This function takes a string and examines it for HTML tags.
 * If tags are detected it passes the string to a helper function {@link cleanAttributes2()}
 *  which checks for attributes and filters them for malicious content
 *         17/08/2004              ::          Eamon DOT Costello AT dcu DOT ie
 *
 * @param string $str The string to be examined for html tags
 * @return string
 */
function cleanAttributes($str){
    $result = preg_replace_callback(
            '%(<[^>]*(>|$)|>)%m', #search for html tags
            "cleanAttributes2",
            $str
            );
    return  $result;
}

/**
 * This function takes a string with an html tag and strips out any unallowed
 * protocols e.g. javascript:
 * It calls ancillary functions in kses which are prefixed by kses
*        17/08/2004              ::          Eamon DOT Costello AT dcu DOT ie
 *
 * @param array $htmlArray An array from {@link cleanAttributes()}, containing in its 1st
 *              element the html to be cleared
 * @return string
 */
function cleanAttributes2($htmlArray){

    global $CFG, $ALLOWED_PROTOCOLS;
    require_once($CFG->libdir .'/kses.php');

    $htmlTag = $htmlArray[1];
    if (substr($htmlTag, 0, 1) != '<') {
        return '>';  //a single character ">" detected
    }
    if (!preg_match('%^<\s*(/\s*)?([a-zA-Z0-9]+)([^>]*)>?$%', $htmlTag, $matches)) {
        return ''; // It's seriously malformed
    }
    $slash = trim($matches[1]); //trailing xhtml slash
    $elem = $matches[2];    //the element name
    $attrlist = $matches[3]; // the list of attributes as a string

    $attrArray = kses_hair($attrlist, $ALLOWED_PROTOCOLS);

    $attStr = '';
    foreach ($attrArray as $arreach) {
        $arreach['name'] = strtolower($arreach['name']);
        if ($arreach['name'] == 'style') {
            $value = $arreach['value'];
            while (true) {
                $prevvalue = $value;
                $value = kses_no_null($value);
                $value = preg_replace("/\/\*.*\*\//Us", '', $value);
                $value = kses_decode_entities($value);
                $value = preg_replace('/(&#[0-9]+)(;?)/', "\\1;", $value);
                $value = preg_replace('/(&#x[0-9a-fA-F]+)(;?)/', "\\1;", $value);
                if ($value === $prevvalue) {
                    $arreach['value'] = $value;
                    break;
                }
            }
            $arreach['value'] = preg_replace("/j\s*a\s*v\s*a\s*s\s*c\s*r\s*i\s*p\s*t/i", "Xjavascript", $arreach['value']);
            $arreach['value'] = preg_replace("/e\s*x\s*p\s*r\s*e\s*s\s*s\s*i\s*o\s*n/i", "Xexpression", $arreach['value']);
            $arreach['value'] = preg_replace("/b\s*i\s*n\s*d\s*i\s*n\s*g/i", "Xbinding", $arreach['value']);
        } else if ($arreach['name'] == 'href') {
            //Adobe Acrobat Reader XSS protection
            $arreach['value'] = preg_replace('/(\.(pdf|fdf|xfdf|xdp|xfd))[^a-z0-9_\.\-].*$/i', '$1', $arreach['value']);
        }
        $attStr .=  ' '.$arreach['name'].'="'.$arreach['value'].'"';
    }

    $xhtml_slash = '';
    if (preg_match('%/\s*$%', $attrlist)) {
        $xhtml_slash = ' /';
    }
    return '<'. $slash . $elem . $attStr . $xhtml_slash .'>';
}

/**
 * Replaces all known smileys in the text with image equivalents
 *
 * @uses $CFG
 * @param string $text Passed by reference. The string to search for smily strings.
 * @return string
 */
function replace_smilies(&$text) {

    global $CFG;

    if (empty($CFG->emoticons)) { /// No emoticons defined, nothing to process here
        return;
    }

    $lang = current_language();
    $emoticonstring = $CFG->emoticons;
    static $e = array();
    static $img = array();
    static $emoticons = null;

    if (is_null($emoticons)) {
        $emoticons = array();
        if ($emoticonstring) {
            $items = explode('{;}', $CFG->emoticons);
            foreach ($items as $item) {
               $item = explode('{:}', $item);
              $emoticons[$item[0]] = $item[1];
            }
        }
    }

    if (empty($img[$lang])) {  /// After the first time this is not run again
        $e[$lang] = array();
        $img[$lang] = array();
        foreach ($emoticons as $emoticon => $image){
            $alttext = get_string($image, 'pix');
            $alttext = preg_replace('/^\[\[(.*)\]\]$/', '$1', $alttext); /// Clean alttext in case there isn't lang string for it.
            $e[$lang][] = $emoticon;
            $img[$lang][] = '';
        }
    }

    // Exclude from transformations all the code inside \n";
        if ($loadlib == $CFG->wwwroot.'/lib/yui/logger/logger-min.js') {
            // Special case, we need the CSS too.
            $output .= 'wwwroot}/lib/yui/logger/assets/logger.css\" />\n";
        }
    }
    return $output;
}

/**
 * Generate the HTML for calling a javascript funtion. You often need to do this
 * if you have your javascript in an external file, and need to call one function
 * to initialise it.
 *
 * You can pass in an optional list of arguments, which are properly escaped for
 * you using the json_encode function.
 *
 * @param string $function the name of the JavaScript function to call.
 * @param array $args an optional list of arguments to the function call.
 * @param boolean $return if true, return the HTML code, otherwise output it.
 * @return mixed string if $return is true, otherwise nothing.
 */
function print_js_call($function, $args = array(), $return = false) {
    $quotedargs = array();
    foreach ($args as $arg) {
        $quotedargs[] = json_encode($arg);
    }
    $html = '';
    $html .= '\n";
    if ($return) {
        return $html;
    } else {
        echo $html;
    }
}

/**
 * Generate the HTML for calling a javascript funtion after a time delay.
 * In other respects, this function is the same as print_js_call.
 *
 * @param integer $delay the desired delay in seconds.
 * @param string $function the name of the JavaScript function to call.
 * @param array $args an optional list of arguments to the function call.
 * @param boolean $return if true, return the HTML code, otherwise output it.
 * @return mixed string if $return is true, otherwise nothing.
 */
function print_delayed_js_call($delay, $function, $args = array(), $return = false) {
    $quotedargs = array();
    foreach ($args as $arg) {
        $quotedargs[] = json_encode($arg);
    }
    $html = '';
    $html .= '\n";
    if ($return) {
        return $html;
    } else {
        echo $html;
    }
}

/**
 * Sometimes you need access to some values in your JavaScript that you can only
 * get from PHP code. You can handle this by generating your JS in PHP, but a
 * better idea is to write static javascrip code that reads some configuration
 * variable, and then just output the configuration variables from PHP using
 * this function.
 *
 * For example, look at the code in question_init_qenginejs_script() in
 * lib/questionlib.php. It writes out a bunch of $settings like
 * 'pixpath' => $CFG->pixpath, with $prefix = 'qengine_config'. This gets output
 * in print_header, then the code in question/qengine.js can access these variables
 * as qengine_config.pixpath, and so on.
 *
 * This method will also work without a prefix, but it is better to avoid that
 * we don't want to add more things than necessary to the global JavaScript scope.
 *
 * This method automatically wrapps the values in quotes, and addslashes_js them.
 *
 * @param array $settings the values you want to write out, as variablename => value.
 * @param string $prefix a namespace prefix to use in the JavaScript.
 * @param boolean $return if true, return the HTML code, otherwise output it.
 * @return mixed string if $return is true, otherwise nothing.
 */
function print_js_config($settings = array(), $prefix='', $return = false) {
    $html = '';
    $html .= '\n";
    if ($return) {
        return $html;
    } else {
        echo $html;
    }
}

/**
 * This function generates the code that defines the standard moodle_cfg object.
 * This object has a number of fields that are values that various pieces of
 * JavaScript code need access too. For example $CFG->wwwroot and $CFG->pixpath.
 *
 * @return string a ';
        $str .= '';
    }

    if ($return) {
        return $str;
    }
    echo $str;
}

/**
 * Returns a turn edit on/off button for course in a self contained form.
 * Used to be an icon, but it's now a simple form button
 *
 * Note that the caller is responsible for capchecks.
 *
 * @uses $CFG
 * @uses $USER
 * @param int $courseid The course  to update by id as found in 'course' table
 * @return string
 */
function update_course_icon($courseid) {
    global $CFG, $USER;

    if (!empty($USER->editing)) {
        $string = get_string('turneditingoff');
        $edit = '0';
    } else {
        $string = get_string('turneditingon');
        $edit = '1';
    }

    return 'frametarget.' method="get" action="'.$CFG->wwwroot.'/course/view.php">'.
           ''.
           ''.
           ''.
           ''.
           ''.
           '';
}

/**
 * Returns a little popup menu for switching roles
 *
 * @uses $CFG
 * @uses $USER
 * @param int $courseid The course  to update by id as found in 'course' table
 * @return string
 */
function switchroles_form($courseid) {

    global $CFG, $USER;


    if (!$context = get_context_instance(CONTEXT_COURSE, $courseid)) {
        return '';
    }

    if (!empty($USER->access['rsw'][$context->path])){  // Just a button to return to normal
        $options = array();
        $options['id'] = $courseid;
        $options['sesskey'] = sesskey();
        $options['switchrole'] = 0;

        return print_single_button($CFG->wwwroot.'/course/view.php', $options,
                                   get_string('switchrolereturn'), 'post', '_self', true);
    }

    if (has_capability('moodle/role:switchroles', $context)) {
        if (!$roles = get_assignable_roles_for_switchrole($context)) {
            return '';   // Nothing to show!
        }
        // unset default user role - it would not work
        unset($roles[$CFG->guestroleid]);
        return popup_form($CFG->wwwroot.'/course/view.php?id='.$courseid.'&sesskey='.sesskey().'&switchrole=',
                          $roles, 'switchrole', '', get_string('switchroleto'), 'switchrole', get_string('switchroleto'), true);
    }

    return '';
}


/**
 * Returns a turn edit on/off button for course in a self contained form.
 * Used to be an icon, but it's now a simple form button
 *
 * @uses $CFG
 * @uses $USER
 * @param int $courseid The course  to update by id as found in 'course' table
 * @return string
 */
function update_mymoodle_icon() {

    global $CFG, $USER;

    if (!empty($USER->editing)) {
        $string = get_string('updatemymoodleoff');
        $edit = '0';
    } else {
        $string = get_string('updatemymoodleon');
        $edit = '1';
    }

    return "frametarget method=\"get\" action=\"$CFG->wwwroot/my/index.php\">".
           "".
           "".
           "";
}

/**
 * Returns a turn edit on/off button for tag in a self contained form.
 *
 * @uses $CFG
 * @uses $USER
 * @return string
 */
function update_tag_button($tagid) {

    global $CFG, $USER;

    if (!empty($USER->editing)) {
        $string = get_string('turneditingoff');
        $edit = '0';
    } else {
        $string = get_string('turneditingon');
        $edit = '1';
    }

    return "frametarget method=\"get\" action=\"$CFG->wwwroot/tag/index.php\">".
           "".
           "".
           "".
           "";
}

/**
 * Prints the editing button on a module "view" page
 *
 * @uses $CFG
 * @param    type description
 * @todo Finish documenting this function
 */
function update_module_button($moduleid, $courseid, $string) {
    global $CFG, $USER;

    if (has_capability('moodle/course:manageactivities', get_context_instance(CONTEXT_MODULE, $moduleid))) {
        $string = get_string('updatethis', '', $string);

        return "frametarget method=\"get\" action=\"$CFG->wwwroot/course/mod.php\" onsubmit=\"this.target='{$CFG->framename}'; return true\">".//hack to allow edit on framed resources
               "".
               "".
               "".
               "".
               "";
    } else {
        return '';
    }
}

/**
 * Prints the editing button on search results listing
 * For bulk move courses to another category
 */

function update_categories_search_button($search,$page,$perpage) {
    global $CFG, $USER;

    // not sure if this capability is the best  here
    if (has_capability('moodle/category:update', get_context_instance(CONTEXT_SYSTEM))) {
        if (!empty($USER->categoryediting)) {
            $string = get_string("turneditingoff");
            $edit = "off";
            $perpage = 30;
        } else {
            $string = get_string("turneditingon");
            $edit = "on";
        }

        return "frametarget method=\"get\" action=\"$CFG->wwwroot/course/search.php\">".
               ''.
               "".
               "sesskey\" />".
               "".
               "".
               "".
               "";
    }
}

/**
 * Given a course and a (current) coursemodule
 * This function returns a small popup menu with all the
 * course activity modules in it, as a navigation menu
 * The data is taken from the serialised array stored in
 * the course record
 *
 * @param course $course A {@link $COURSE} object.
 * @param course $cm A {@link $COURSE} object.
 * @param string $targetwindow ?
 * @return string
 * @todo Finish documenting this function
 */
function navmenu($course, $cm=NULL, $targetwindow='self') {

    global $CFG, $THEME, $USER, $DB;

    if (empty($THEME->navmenuwidth)) {
        $width = 50;
    } else {
        $width = $THEME->navmenuwidth;
    }

    if ($cm) {
        $cm = $cm->id;
    }

    if ($course->format == 'weeks') {
        $strsection = get_string('week');
    } else {
        $strsection = get_string('topic');
    }
    $strjumpto = get_string('jumpto');

    $modinfo = get_fast_modinfo($course);
    $context = get_context_instance(CONTEXT_COURSE, $course->id);

    $section = -1;
    $selected = '';
    $url = '';
    $previousmod = NULL;
    $backmod = NULL;
    $nextmod = NULL;
    $selectmod = NULL;
    $logslink = NULL;
    $flag = false;
    $menu = array();
    $menustyle = array();

    $sections = $DB->get_records('course_sections', array('course'=>$course->id), 'section', 'section,visible,summary');

    if (!empty($THEME->makenavmenulist)) {   /// A hack to produce an XHTML navmenu list for use in themes
        $THEME->navmenulist = navmenulist($course, $sections, $modinfo, $strsection, $strjumpto, $width, $cm);
    }

    foreach ($modinfo->cms as $mod) {
        if ($mod->modname == 'label') {
            continue;
        }

        if ($mod->sectionnum > $course->numsections) {   /// Don't show excess hidden sections
            break;
        }

        if (!$mod->uservisible) { // do not icnlude empty sections at all
            continue;
        }

        if ($mod->sectionnum > 0 and $section != $mod->sectionnum) {
            $thissection = $sections[$mod->sectionnum];

            if ($thissection->visible or !$course->hiddensections or
                has_capability('moodle/course:viewhiddensections', $context)) {
                $thissection->summary = strip_tags(format_string($thissection->summary,true));
                if ($course->format == 'weeks' or empty($thissection->summary)) {
                    $menu[] = '--'.$strsection ." ". $mod->sectionnum;
                } else {
                    if (strlen($thissection->summary) < ($width-3)) {
                        $menu[] = '--'.$thissection->summary;
                    } else {
                        $menu[] = '--'.substr($thissection->summary, 0, $width).'...';
                    }
                }
                $section = $mod->sectionnum;
            } else {
                // no activities from this hidden section shown
                continue;
            }
        }

        $url = $mod->modname.'/view.php?id='. $mod->id;
        if ($flag) { // the current mod is the "next" mod
            $nextmod = $mod;
            $flag = false;
        }
        $localname = $mod->name;
        if ($cm == $mod->id) {
            $selected = $url;
            $selectmod = $mod;
            $backmod = $previousmod;
            $flag = true; // set flag so we know to use next mod for "next"
            $localname = $strjumpto;
            $strjumpto = '';
        } else {
            $localname = strip_tags(format_string($localname,true));
            $tl=textlib_get_instance();
            if ($tl->strlen($localname) > ($width+5)) {
                $localname = $tl->substr($localname, 0, $width).'...';
            }
            if (!$mod->visible) {
                $localname = '('.$localname.')';
            }
        }
        $menu[$url] = $localname;
        if (empty($THEME->navmenuiconshide)) {
            $menustyle[$url] = 'style="background-image: url('.$CFG->modpixpath.'/'.$mod->modname.'/icon.gif);"';  // Unfortunately necessary to do this here
        }
        $previousmod = $mod;
    }
    //Accessibility: added Alt text, replaced > < with 'silent' character and 'accesshide' text.

    if ($selectmod and has_capability('coursereport/log:view', $context)) {
        $logstext = get_string('alllogs');
        $logslink = ''."\n".'frametarget.'onclick="this.target=\''.$CFG->framename.'\';"'.' href="'.
                    $CFG->wwwroot.'/course/report/log/index.php?chooselog=1&user=0&date=0&id='.
                       $course->id.'&modid='.$selectmod->id.'">'.
                    ''."\n".'';

    }
    if ($backmod) {
        $backtext= get_string('activityprev', 'access');
        $backmod = ''.
                   ''.
                   ''.link_arrow_left($backtext, $url='', $accesshide=true).
                   '';
    }
    if ($nextmod) {
        $nexttext= get_string('activitynext', 'access');
        $nextmod = ''.
                   ''.
                   ''.link_arrow_right($nexttext, $url='', $accesshide=true).
                   '';
    }

    return ''."\n".''.$logslink . $backmod .
            ''.popup_form($CFG->wwwroot .'/mod/', $menu, 'navmenupopup', $selected, $strjumpto,
                       '', '', true, $targetwindow, '', $menustyle).''.
            $nextmod . ''."\n".'';
}

/**
 * Given a course
 * This function returns a small popup menu with all the
 * course activity modules in it, as a navigation menu
 * outputs a simple list structure in XHTML
 * The data is taken from the serialised array stored in
 * the course record
 *
 * @param course $course A {@link $COURSE} object.
 * @return string
 * @todo Finish documenting this function
 */
function navmenulist($course, $sections, $modinfo, $strsection, $strjumpto, $width=50, $cmid=0) {

    global $CFG;

    $section = -1;
    $url = '';
    $menu = array();
    $doneheading = false;

    $coursecontext = get_context_instance(CONTEXT_COURSE, $course->id);

    $menu[] = ''.$strjumpto.'';
    foreach ($modinfo->cms as $mod) {
        if ($mod->modname == 'label') {
            continue;
        }

        if ($mod->sectionnum > $course->numsections) {   /// Don't show excess hidden sections
            break;
        }

        if (!$mod->uservisible) { // do not icnlude empty sections at all
            continue;
        }

        if ($mod->sectionnum >= 0 and $section != $mod->sectionnum) {
            $thissection = $sections[$mod->sectionnum];

            if ($thissection->visible or !$course->hiddensections or
                      has_capability('moodle/course:viewhiddensections', $coursecontext)) {
                $thissection->summary = strip_tags(format_string($thissection->summary,true));
                if (!$doneheading) {
                    $menu[] = '';
                }
                if ($course->format == 'weeks' or empty($thissection->summary)) {
                    $item = $strsection ." ". $mod->sectionnum;
                } else {
                    if (strlen($thissection->summary) < ($width-3)) {
                        $item = $thissection->summary;
                    } else {
                        $item = substr($thissection->summary, 0, $width).'...';
                    }
                }
                $menu[] = ''.$item.'';
                $menu[] = '';
                $doneheading = true;

                $section = $mod->sectionnum;
            } else {
                // no activities from this hidden section shown
                continue;
            }
        }

        $url = $mod->modname .'/view.php?id='. $mod->id;
        $mod->name = strip_tags(format_string(urldecode($mod->name),true));
        if (strlen($mod->name) > ($width+5)) {
            $mod->name = substr($mod->name, 0, $width).'...';
        }
        if (!$mod->visible) {
            $mod->name = '('.$mod->name.')';
        }
        $class = 'activity '.$mod->modname;
        $class .= ($cmid == $mod->cm) ? ' selected' : '';
        $menu[] = ''.
                  ''.
                  ''.$mod->name.'';
    }

    if ($doneheading) {
        $menu[] = '';
    }
    $menu[] = '';

    return implode("\n", $menu);
}

/**
 * Prints form items with the names $day, $month and $year
 *
 * @param string $day   fieldname
 * @param string $month  fieldname
 * @param string $year  fieldname
 * @param int $currenttime A default timestamp in GMT
 * @param boolean $return
 */
function print_date_selector($day, $month, $year, $currenttime=0, $return=false) {

    if (!$currenttime) {
        $currenttime = time();
    }
    $currentdate = usergetdate($currenttime);

    for ($i=1; $i<=31; $i++) {
        $days[$i] = $i;
    }
    for ($i=1; $i<=12; $i++) {
        $months[$i] = userdate(gmmktime(12,0,0,$i,15,2000), "%B");
    }
    for ($i=1970; $i<=2020; $i++) {
        $years[$i] = $i;
    }
    return choose_from_menu($days,   $day,   $currentdate['mday'], '', '', '0', $return)
          .choose_from_menu($months, $month, $currentdate['mon'],  '', '', '0', $return)
          .choose_from_menu($years,  $year,  $currentdate['year'], '', '', '0', $return);

}

/**
 *Prints form items with the names $hour and $minute
 *
 * @param string $hour  fieldname
 * @param string ? $minute  fieldname
 * @param $currenttime A default timestamp in GMT
 * @param int $step minute spacing
 * @param boolean $return
 */
function print_time_selector($hour, $minute, $currenttime=0, $step=5, $return=false) {

    if (!$currenttime) {
        $currenttime = time();
    }
    $currentdate = usergetdate($currenttime);
    if ($step != 1) {
        $currentdate['minutes'] = ceil($currentdate['minutes']/$step)*$step;
    }
    for ($i=0; $i<=23; $i++) {
        $hours[$i] = sprintf("%02d",$i);
    }
    for ($i=0; $i<=59; $i+=$step) {
        $minutes[$i] = sprintf("%02d",$i);
    }

    return choose_from_menu($hours,   $hour,   $currentdate['hours'],   '','','0',$return)
          .choose_from_menu($minutes, $minute, $currentdate['minutes'], '','','0',$return);
}

/**
 * Prints time limit value selector
 *
 * @uses $CFG
 * @param int $timelimit default
 * @param string $unit
 * @param string $name
 * @param boolean $return
 */
function print_timer_selector($timelimit = 0, $unit = '', $name = 'timelimit', $return=false) {

    global $CFG;

    if ($unit) {
        $unit = ' '.$unit;
    }

    // Max timelimit is sessiontimeout - 10 minutes.
    $maxvalue = ($CFG->sessiontimeout / 60) - 10;

    for ($i=1; $i<=$maxvalue; $i++) {
        $minutes[$i] = $i.$unit;
    }
    return choose_from_menu($minutes, $name, $timelimit, get_string('none'), '','','0',$return);
}

/**
 * Prints a grade menu (as part of an existing form) with help
 * Showing all possible numerical grades and scales
 *
 * @uses $CFG
 * @param int $courseid ?
 * @param string $name ?
 * @param string $current ?
 * @param boolean $includenograde ?
 * @todo Finish documenting this function
 */
function print_grade_menu($courseid, $name, $current, $includenograde=true, $return=false) {

    global $CFG;

    $output = '';
    $strscale = get_string('scale');
    $strscales = get_string('scales');

    $scales = get_scales_menu($courseid);
    foreach ($scales as $i => $scalename) {
        $grades[-$i] = $strscale .': '. $scalename;
    }
    if ($includenograde) {
        $grades[0] = get_string('nograde');
    }
    for ($i=100; $i>=1; $i--) {
        $grades[$i] = $i;
    }
    $output .= choose_from_menu($grades, $name, $current, '', '', 0, true);

    $linkobject = '';
    $output .= link_to_popup_window ('/course/scales.php?id='. $courseid .'&list=true', 'ratingscales',
                                     $linkobject, 400, 500, $strscales, 'none', true);

    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}

/**
 * Prints a scale menu (as part of an existing form) including help button
 * Just like {@link print_grade_menu()} but without the numeric grades
 *
 * @param int $courseid ?
 * @param string $name ?
 * @param string $current ?
 * @todo Finish documenting this function
 */
function print_scale_menu($courseid, $name, $current, $return=false) {

    global $CFG;

    $output = '';
    $strscales = get_string('scales');
    $output .= choose_from_menu(get_scales_menu($courseid), $name, $current, '', '', 0, true);

    $linkobject = '';
    $output .= link_to_popup_window ('/course/scales.php?id='. $courseid .'&list=true', 'ratingscales',
                                     $linkobject, 400, 500, $strscales, 'none', true);
    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}

/**
 * Prints a help button about a scale
 *
 * @uses $CFG
 * @param id $courseid ?
 * @param object $scale ?
 * @todo Finish documenting this function
 */
function print_scale_menu_helpbutton($courseid, $scale, $return=false) {

    global $CFG;

    $output = '';
    $strscales = get_string('scales');

    $linkobject = '';
    $output .= link_to_popup_window ('/course/scales.php?id='. $courseid .'&list=true&scaleid='. $scale->id, 'ratingscale',
                                     $linkobject, 400, 500, $scale->name, 'none', true);
    if ($return) {
        return $output;
    } else {
        echo $output;
    }
}

/**
 * Print an error page displaying an error message.  New method - use this for new code.
 *
 * @param string $errorcode The name of the string from error.php to print
 * @param string $module name of module
 * @param string $link The url where the user will be prompted to continue. If no url is provided the user will be directed to the site index page.
 * @param object $a Extra words and phrases that might be required in the error string
 * @return terminates script, does not return!
 */
function print_error($errorcode, $module='error', $link='', $a=NULL) {
    global $CFG, $UNITTEST;

    // If unittest running, throw exception instead
    if (!empty($UNITTEST->running)) {
        // Errors in unit test become exceptions, so you can unit test
        // code that might call error().
        throw new moodle_exception($errorcode, $module, $link, $a);
    }

    if (empty($module) || $module == 'moodle' || $module == 'core') {
        $module = 'error';
    }

    if (!isset($CFG->theme) or !isset($CFG->stylesheets)) {
        // error found before setup.php finished
        _print_early_error($errorcode, $module, $a);
    } else {
        _print_normal_error($errorcode, $module, $a, $link, debug_backtrace());
    }
}

/**
 * Internal function - do not use directly!!
 */
function _print_normal_error($errorcode, $module, $a, $link, $backtrace, $debuginfo=null, $showerrordebugwarning=false) {
    global $CFG, $SESSION, $THEME, $DB;

    if ($DB) {
        //if you enable db debugging and exception is thrown, the print footer prints a lot of rubbish
        $DB->set_debug(0);
    }

    if ($module === 'error') {
        $modulelink = 'moodle';
    } else {
        $modulelink = $module;
    }

    $message = get_string($errorcode, $module, $a);
    if ($module === 'error' and strpos($message, '[[') === 0) {
        //search in moodle file if error specified - needed for backwards compatibility
        $message = get_string($errorcode, 'moodle', $a);
    }

    if (defined('FULLME') && FULLME == 'cron') {
        // Errors in cron should be mtrace'd.
        mtrace($message);
        die;
    }

    if (empty($link) and !defined('ADMIN_EXT_HEADER_PRINTED')) {
        if ( !empty($SESSION->fromurl) ) {
            $link = $SESSION->fromurl;
            unset($SESSION->fromurl);
        } else {
            $link = $CFG->wwwroot .'/';
        }
    }

    if (!empty($CFG->errordocroot)) {
        $errordocroot = $CFG->errordocroot;
    } else if (!empty($CFG->docroot)) {
        $errordocroot = $CFG->docroot;
    } else {
        $errordocroot = 'http://docs.moodle.org';
    }

    if (! defined('HEADER_PRINTED')) {
        //header not yet printed
        @header('HTTP/1.0 404 Not Found');
        print_header(get_string('error'));
    } else {
        print_container_end_all(false, $THEME->open_header_containers);
    }

    echo '';

    $message = clean_text(''.$message.''.
               ''.
               ''.
                 get_string('moreinformation').'');

    print_simple_box($message, '', '', '', '', 'errorbox');

    if ($showerrordebugwarning) {
        debugging('error() is a deprecated function, please call print_error() instead of error()', DEBUG_DEVELOPER);

    } else {
        if (debugging('', DEBUG_DEVELOPER)) {
            if ($debuginfo) {
                debugging($debuginfo, DEBUG_DEVELOPER, $backtrace);
            } else {
                notify('Stack trace:'.print_backtrace($backtrace, true), 'notifytiny');
            }
        }
    }

    // in case we are logging upgrade in admin/index.php stop it
    if (function_exists('upgrade_log_finish')) {
        upgrade_log_finish();
    }

    if (!empty($link)) {
        print_continue($link);
    }

    print_footer();

    for ($i=0;$i<512;$i++) {  // Padding to help IE work with 404
        echo ' ';
    }
    die;
}

/**
 * Internal function - do not use directly!!
 * This function is used if fatal error occures before the themes are fully initialised (eg. in lib/setup.php)
 */
function _print_early_error($errorcode, $module, $a, $backtrace=null, $debuginfo=null) {
    $message = get_string($errorcode, $module, $a);
    if ($module === 'error' and strpos($message, '[[') === 0) {
        //search in moodle file if error specified - needed for backwards compatibility
        $message = get_string($errorcode, 'moodle', $a);
    }
    $message = clean_text($message);

    // In the name of protocol correctness, monitoring and performance
    // profiling, set the appropriate error headers for machine comsumption
    if (isset($_SERVER['SERVER_PROTOCOL'])) {
        // Avoid it with cron.php. Note that we assume it's HTTP/1.x
        @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
    }

    // better disable any caching
    @header('Content-Type: text/html; charset=utf-8');
    @header('Cache-Control: no-store, no-cache, must-revalidate');
    @header('Cache-Control: post-check=0, pre-check=0', false);
    @header('Pragma: no-cache');
    @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
    @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');

    echo '



'.get_string('error').'


'.$message.'
';
    if (debugging('', DEBUG_DEVELOPER)) {
        if ($debuginfo) {
            debugging($debuginfo, DEBUG_DEVELOPER, $backtrace);
        } else {
            notify('Stack trace:'.print_backtrace($backtrace, true), 'notifytiny');
        }
    }

    echo '';
    die;
}

/**
 * Print an error to STDOUT and exit with a non-zero code. For commandline scripts.
 * Default errorcode is 1.
 *
 * Very useful for perl-like error-handling:
 *
 * do_somethting() or mdie("Something went wrong");
 *
 * @param string  $msg       Error message
 * @param integer $errorcode Error code to emit
 */
function mdie($msg='', $errorcode=1) {
    trigger_error($msg);
    exit($errorcode);
}

/**
 * Returns a string of html with an image of a help icon linked to a help page on a number of help topics.
 * Should be used only with htmleditor or textarea.
 * @param mixed $helptopics variable amount of params accepted. Each param may be a string or an array of arguments for
 *                  helpbutton.
 * @return string
 */
function editorhelpbutton(){
    global $CFG, $SESSION;
    $items = func_get_args();
    $i = 1;
    $urlparams = array();
    $titles = array();
    foreach ($items as $item){
        if (is_array($item)){
            $urlparams[] = "keyword$i=".urlencode($item[0]);
            $urlparams[] = "title$i=".urlencode($item[1]);
            if (isset($item[2])){
                $urlparams[] = "module$i=".urlencode($item[2]);
            }
            $titles[] = trim($item[1], ". \t");
        } else if (is_string($item)) {
            $urlparams[] = "button$i=".urlencode($item);
            switch ($item) {
                case 'reading' :
                    $titles[] = get_string("helpreading");
                    break;
                case 'writing' :
                    $titles[] = get_string("helpwriting");
                    break;
                case 'questions' :
                    $titles[] = get_string("helpquestions");
                    break;
                case 'emoticons2' :
                    $titles[] = get_string("helpemoticons");
                    break;
                case 'richtext2' :
                    $titles[] = get_string('helprichtext');
                    break;
                case 'text2' :
                    $titles[] = get_string('helptext');
                    break;
                default :
                    print_error('unknownhelp', '', '', $item);
            }
        }
        $i++;
    }
    if (count($titles)>1){
        //join last two items with an 'and'
        $a = new object();
        $a->one = $titles[count($titles) - 2];
        $a->two = $titles[count($titles) - 1];
        $titles[count($titles) - 2] = get_string('and', '', $a);
        unset($titles[count($titles) - 1]);
    }
    $alttag = join (', ', $titles);

    $paramstring = join('&', $urlparams);
    $linkobject = '';
    return link_to_popup_window(s('/lib/form/editorhelp.php?'.$paramstring), 'popup', $linkobject, 400, 500, $alttag, 'none', true);
}

/**
 * Print a help button.
 *
 * @uses $CFG
 * @param string $page  The keyword that defines a help page
 * @param string $title The title of links, rollover tips, alt tags etc
 *           'Help with' (or the language equivalent) will be prefixed and '...' will be stripped.
 * @param string $module Which module is the page defined in
 * @param mixed $image Use a help image for the link?  (true/false/"both")
 * @param boolean $linktext If true, display the title next to the help icon.
 * @param string $text If defined then this text is used in the page, and
 *           the $page variable is ignored.
 * @param boolean $return If true then the output is returned as a string, if false it is printed to the current page.
 * @param string $imagetext The full text for the helpbutton icon. If empty use default help.gif
 * @return string
 * @todo Finish documenting this function
 */
function helpbutton($page, $title, $module='moodle', $image=true, $linktext=false, $text='', $return=false,
                     $imagetext='') {
    global $CFG, $COURSE;

    //warning if ever $text parameter is used
    //$text option won't work properly because the text needs to be always cleaned and,
    // when cleaned... html tags always break, so it's unusable.
    if ( isset($text) && $text!='') {
        debugging('Warning: it\'s not recommended to use $text parameter in helpbutton ($page=' . $page . ', $module=' . $module . ') function', DEBUG_DEVELOPER);
    }

    // fix for MDL-7734
    if (!empty($COURSE->lang)) {
        $forcelang = $COURSE->lang;
    } else {
        $forcelang = '';
    }

    // Catch references to the old text.html and emoticons.html help files that
    // were renamed in MDL-13233.
    if (in_array($page, array('text', 'emoticons', 'richtext'))) {
        $oldname = $page;
        $page .= '2';
        debugging("You are referring to the old help file '$oldname'. " .
                "This was renamed to '$page' becuase of MDL-13233. " .
                "Please update your code.", DEBUG_DEVELOPER);
    }

    if ($module == '') {
        $module = 'moodle';
    }

    if ($title == '' && $linktext == '') {
        debugging('Error in call to helpbutton function: at least one of $title and $linktext is required');
    }

    // Warn users about new window for Accessibility
    $tooltip = get_string('helpprefix2', '', trim($title, ". \t")) .' ('.get_string('newwindow').')';

    $linkobject = '';

    if ($image) {
        if ($linktext) {
            // MDL-7469 If text link is displayed with help icon, change to alt to "help with this".
            $linkobject .= $title.' ';
            $tooltip = get_string('helpwiththis');
        }
        if ($imagetext) {
            $linkobject .= $imagetext;
        } else {
            $linkobject .= '';
        }
    } else {
        $linkobject .= $tooltip;
    }

    // fix for MDL-7734
    if ($text) {
        $url = '/help.php?module='. $module .'&text='. s(urlencode($text).'&forcelang='.$forcelang);
    } else {
        $url = '/help.php?module='. $module .'&file='. $page .'.html&forcelang='.$forcelang;
    }

    $link = ''.
            link_to_popup_window ($url, 'popup', $linkobject, 400, 500, $tooltip, 'none', true).
            '';

    if ($return) {
        return $link;
    } else {
        echo $link;
    }
}

/**
 * Print a help button.
 *
 * Prints a special help button that is a link to the "live" emoticon popup
 * @uses $CFG
 * @uses $SESSION
 * @param string $form ?
 * @param string $field ?
 * @todo Finish documenting this function
 */
function emoticonhelpbutton($form, $field, $return = false) {

    global $CFG, $SESSION;

    $SESSION->inserttextform = $form;
    $SESSION->inserttextfield = $field;
    $imagetext = '';
    $help = helpbutton('emoticons2', get_string('helpemoticons'), 'moodle', true, true, '', true, $imagetext);
    if (!$return){
        echo $help;
    } else {
        return $help;
    }
}

/**
 * Print a help button.
 *
 * Prints a special help button for html editors (htmlarea in this case)
 * @uses $CFG
 */
function editorshortcutshelpbutton() {

    global $CFG;
    //TODO: detect current editor and print correct info
/*    $imagetext = '';

    return helpbutton('editorshortcuts', get_string('editorshortcutkeys'), 'moodle', true, false, '', true, $imagetext);*/
    return '';
}

/**
 * Print a message and exit.
 *
 * @uses $CFG
 * @param string $message ?
 * @param string $link ?
 * @todo Finish documenting this function
 */
function notice ($message, $link='', $course=NULL) {
    global $CFG, $SITE, $THEME, $COURSE;

    $message = clean_text($message);   // In case nasties are in here

    if (defined('FULLME') && FULLME == 'cron') {
        // notices in cron should be mtrace'd.
        mtrace($message);
        die;
    }

    if (! defined('HEADER_PRINTED')) {
        //header not yet printed
        print_header(get_string('notice'));
    } else {
        print_container_end_all(false, $THEME->open_header_containers);
    }

    print_box($message, 'generalbox', 'notice');
    print_continue($link);

    if (empty($course)) {
        print_footer($COURSE);
    } else {
        print_footer($course);
    }
    exit;
}

/**
 * Print a message along with "Yes" and "No" links for the user to continue.
 *
 * @param string $message The text to display
 * @param string $linkyes The link to take the user to if they choose "Yes"
 * @param string $linkno The link to take the user to if they choose "No"
 * TODO Document remaining arguments
 */
function notice_yesno ($message, $linkyes, $linkno, $optionsyes=NULL, $optionsno=NULL, $methodyes='post', $methodno='post') {

    global $CFG;

    $message = clean_text($message);
    $linkyes = clean_text($linkyes);
    $linkno = clean_text($linkno);

    print_box_start('generalbox', 'notice');
    echo ''. $message .'';
    echo '';
    print_single_button($linkyes, $optionsyes, get_string('yes'), $methodyes, $CFG->framename);
    print_single_button($linkno,  $optionsno,  get_string('no'),  $methodno,  $CFG->framename);
    echo '';
    print_box_end();
}

/**
 * Redirects the user to another page, after printing a notice
 *
 * @param string $url The url to take the user to
 * @param string $message The text message to display to the user about the redirect, if any
 * @param string $delay How long before refreshing to the new page at $url?
 * @todo '&' needs to be encoded into '&' for XHTML compliance,
 *      however, this is not true for javascript. Therefore we
 *      first decode all entities in $url (since we cannot rely on)
 *      the correct input) and then encode for where it's needed
 *      echo "";
 */
function redirect($url, $message='', $delay=-1) {
    global $CFG, $THEME, $SESSION;

    if (!empty($CFG->usesid) && !isset($_COOKIE[session_name()])) {
       $url = $SESSION->sid_process_url($url);
    }

    $message = clean_text($message);

    $encodedurl = preg_replace("/\&(?![a-zA-Z0-9#]{1,8};)/", "&", $url);
    $encodedurl = preg_replace('/^.*href="([^"]*)".*$/', "\\1", clean_text(''));
    $url = str_replace('&', '&', $encodedurl);

/// At developer debug level. Don't redirect if errors have been printed on screen.
/// Currenly only works in PHP 5.2+; we do not want strict PHP5 errors
    $lasterror = error_get_last();
    $error = defined('DEBUGGING_PRINTED') or (!empty($lasterror) && ($lasterror['type'] & DEBUG_DEVELOPER));
    $errorprinted = debugging('', DEBUG_ALL) && $CFG->debugdisplay && $error;
    if ($errorprinted) {
        $message = "Error output, so disabling automatic redirect." . $message;
    }

    $performanceinfo = '';
    if (defined('MDL_PERF') || (!empty($CFG->perfdebug) and $CFG->perfdebug > 7)) {
        if (defined('MDL_PERFTOLOG') && !function_exists('register_shutdown_function')) {
            $perf = get_performance_info();
            error_log("PERF: " . $perf['txt']);
        }
    }

/// when no message and header printed yet, try to redirect
    if (empty($message) and !defined('HEADER_PRINTED')) {

        // Technically, HTTP/1.1 requires Location: header to contain
        // the absolute path. (In practice browsers accept relative
        // paths - but still, might as well do it properly.)
        // This code turns relative into absolute.
        if (!preg_match('|^[a-z]+:|', $url)) {
            // Get host name http://www.wherever.com
            $hostpart = preg_replace('|^(.*?[^:/])/.*$|', '$1', $CFG->wwwroot);
            if (preg_match('|^/|', $url)) {
                // URLs beginning with / are relative to web server root so we just add them in
                $url = $hostpart.$url;
            } else {
                // URLs not beginning with / are relative to path of current script, so add that on.
                $url = $hostpart.preg_replace('|\?.*$|','',me()).'/../'.$url;
            }
            // Replace all ..s
            while (true) {
                $newurl = preg_replace('|/(?!\.\.)[^/]*/\.\./|', '/', $url);
                if ($newurl == $url) {
                    break;
                }
                $url = $newurl;
            }
        }

        $delay = 0;
        //try header redirection first
        @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other'); //302 might not work for POST requests, 303 is ignored by obsolete clients
        @header('Location: '.$url);
        //another way for older browsers and already sent headers (eg trailing whitespace in config.php)
        echo '';
        print_js_call('document.location.replace', array($url));
        die;
    }

    if ($delay == -1) {
        $delay = 3;  // if no delay specified wait 3 seconds
    }
    if (! defined('HEADER_PRINTED')) {
        // this type of redirect might not be working in some browsers - such as lynx :-(
        print_header('', '', '', '', $errorprinted ? '' : (''));
        $delay += 3; // double redirect prevention, it was sometimes breaking upgrades before 1.7
    } else {
        print_container_end_all(false, $THEME->open_header_containers);
    }
    echo '';
    echo '' . $message . '';
    echo '( '. get_string('continue') .' )';
    echo '';

    if (!$errorprinted) {
        print_delayed_js_call($delay, 'document.location.replace', array($url));
    }

    $CFG->docroot = false; // to prevent the link to moodle docs from being displayed on redirect page.
    print_footer('none');
    die;
}

/**
 * Print a bold message in an optional color.
 *
 * @param string $message The message to print out
 * @param string $style Optional style to display message text in
 * @param string $align Alignment option
 * @param bool $return whether to return an output string or echo now
 */
function notify($message, $style='notifyproblem', $align='center', $return=false) {
    global $DB;

    if ($style == 'green') {
        $style = 'notifysuccess';  // backward compatible with old color system
    }

    $message = clean_text($message);
    if(!defined('CLI_UPGRADE')||!CLI_UPGRADE) {
    $output = ''. $message .''."\n";
    } else if (CLI_UPGRADE && $DB->get_debug()) {
        $output = '++'.$message.'++';
        return ;
    }

    if ($return) {
        return $output;
    }
    echo $output;
}


/**
 * Given an email address, this function will return an obfuscated version of it
 *
 * @param string $email The email address to obfuscate
 * @return string
 */
 function obfuscate_email($email) {

    $i = 0;
    $length = strlen($email);
    $obfuscated = '';
    while ($i < $length) {
        if (rand(0,2)) {
            $obfuscated.='%'.dechex(ord($email{$i}));
        } else {
            $obfuscated.=$email{$i};
        }
        $i++;
    }
    return $obfuscated;
}

/**
 * This function takes some text and replaces about half of the characters
 * with HTML entity equivalents.   Return string is obviously longer.
 *
 * @param string $plaintext The text to be obfuscated
 * @return string
 */
function obfuscate_text($plaintext) {

    $i=0;
    $length = strlen($plaintext);
    $obfuscated='';
    $prev_obfuscated = false;
    while ($i < $length) {
        $c = ord($plaintext{$i});
        $numerical = ($c >= ord('0')) && ($c <= ord('9'));
        if ($prev_obfuscated and $numerical ) {
            $obfuscated.='&#'.ord($plaintext{$i}).';';
        } else if (rand(0,2)) {
            $obfuscated.='&#'.ord($plaintext{$i}).';';
            $prev_obfuscated = true;
        } else {
            $obfuscated.=$plaintext{$i};
            $prev_obfuscated = false;
        }
      $i++;
    }
    return $obfuscated;
}

/**
 * This function uses the {@link obfuscate_email()} and {@link obfuscate_text()}
 * to generate a fully obfuscated email link, ready to use.
 *
 * @param string $email The email address to display
 * @param string $label The text to dispalyed as hyperlink to $email
 * @param boolean $dimmed If true then use css class 'dimmed' for hyperlink
 * @return string
 */
function obfuscate_mailto($email, $label='', $dimmed=false) {

    if (empty($label)) {
        $label = $email;
    }
    if ($dimmed) {
        $title = get_string('emaildisable');
        $dimmed = ' class="dimmed"';
    } else {
        $title = '';
        $dimmed = '';
    }
    return sprintf("%s",
                    obfuscate_text('mailto'), obfuscate_email($email),
                    obfuscate_text($label));
}

/**
 * Prints a single paging bar to provide access to other pages  (usually in a search)
 *
 * @param int $totalcount Thetotal number of entries available to be paged through
 * @param int $page The page you are currently viewing
 * @param int $perpage The number of entries that should be shown per page
 * @param mixed $baseurl If this  is a string then it is the url which will be appended with $pagevar, an equals sign and the page number.
 *                          If this is a moodle_url object then the pagevar param will be replaced by the page no, for each page.
 * @param string $pagevar This is the variable name that you use for the page number in your code (ie. 'tablepage', 'blogpage', etc)
 * @param bool $nocurr do not display the current page as a link
 * @param bool $return whether to return an output string or echo now
 * @return bool or string
 */
function print_paging_bar($totalcount, $page, $perpage, $baseurl, $pagevar='page',$nocurr=false, $return=false) {
    $maxdisplay = 18;
    $output = '';

    if ($totalcount > $perpage) {
        $output .= '';
        $output .= get_string('page') .':';
        if ($page > 0) {
            $pagenum = $page - 1;
            if (!is_a($baseurl, 'moodle_url')){
                $output .= ' ('. get_string('previous') .') ';
            } else {
                $output .= ' ('. get_string('previous') .') ';
            }
        }
        if ($perpage > 0) {
            $lastpage = ceil($totalcount / $perpage);
        } else {
            $lastpage = 1;
        }
        if ($page > 15) {
            $startpage = $page - 10;
            if (!is_a($baseurl, 'moodle_url')){
                $output .= ' 1 ...';
            } else {
                $output .= ' 1 ...';
            }
        } else {
            $startpage = 0;
        }
        $currpage = $startpage;
        $displaycount = $displaypage = 0;
        while ($displaycount < $maxdisplay and $currpage < $lastpage) {
            $displaypage = $currpage+1;
            if ($page == $currpage && empty($nocurr)) {
                $output .= '  '. $displaypage;
            } else {
                if (!is_a($baseurl, 'moodle_url')){
                    $output .= '  '. $displaypage .'';
                } else {
                    $output .= '  '. $displaypage .'';
                }

            }
            $displaycount++;
            $currpage++;
        }
        if ($currpage < $lastpage) {
            $lastpageactual = $lastpage - 1;
            if (!is_a($baseurl, 'moodle_url')){
                $output .= ' ...'. $lastpage .' ';
            } else {
                $output .= ' ...'. $lastpage .' ';
            }
        }
        $pagenum = $page + 1;
        if ($pagenum != $displaypage) {
            if (!is_a($baseurl, 'moodle_url')){
                $output .= '  ('. get_string('next') .')';
            } else {
                $output .= '  ('. get_string('next') .')';
            }
        }
        $output .= '';
    }

    if ($return) {
        return $output;
    }

    echo $output;
    return true;
}

/**
 * This function is used to rebuild the  tag because some formats (PLAIN and WIKI)
 * will transform it to html entities
 *
 * @param string $text Text to search for nolink tag in
 * @return string
 */
function rebuildnolinktag($text) {

    $text = preg_replace('/<(\/*nolink)>/i','<$1>',$text);

    return $text;
}

/**
 * Prints a nice side block with an optional header.  The content can either
 * be a block of HTML or a list of text with optional icons.
 *
 * @param string $heading HTML for the heading. Can include full HTML or just
 *   plain text - plain text will automatically be enclosed in the appropriate
 *   heading tags.
 * @param string $content HTML for the content
 * @param array $list an alternative to $content, it you want a list of things with optional icons.
 * @param array $icons optional icons for the things in $list.
 * @param string $footer Extra HTML content that gets output at the end, inside a <div class="footer">
 * @param array $attributes an array of attribute => value pairs that are put on the
 * outer div of this block. If there is a class attribute ' sideblock' gets appended to it. If there isn't
 * already a class, class='sideblock' is used.
 * @param string $title Plain text title, as embedded in the $heading.
 * @todo Finish documenting this function. Show example of various attributes, etc.
 */
function print_side_block($heading='', $content='', $list=NULL, $icons=NULL, $footer='', $attributes = array(), $title='') {

    //Accessibility: skip block link, with title-text (or $block_id) to differentiate links.
    static $block_id = 0;
    $block_id++;
    if (empty($heading)) {
        $skip_text = get_string('skipblock', 'access').' '.$block_id;
    }
    else {
        $skip_text = get_string('skipa', 'access', strip_tags($title));
    }
    $skip_link = ''.$skip_text.'';
    $skip_dest = '';

    if (! empty($heading)) {
        echo $skip_link;
    }
    //ELSE: a single link on a page "Skip block 4" is too confusing - ignore.

    print_side_block_start($heading, $attributes);

    // The content.
    if ($content) {
        echo $content;
    } else {
        if ($list) {
            $row = 0;
            //Accessibility: replaced unnecessary table with list, see themes/standard/styles_layout.css
            echo "\n\n";
            foreach ($list as $key => $string) {
                echo '';
                if ($icons) {
                    echo ''. $icons[$key] .'';
                }
                echo ''. $string .'';
                echo "\n";
                $row = $row ? 0:1;
            }
            echo "\n";
        }
    }

    // Footer, if any.
    if ($footer) {
        echo ''. $footer .'';
    }

    print_side_block_end($attributes, $title);
    echo $skip_dest;
}

/**
 * Starts a nice side block with an optional header.
 *
 * @param string $heading HTML for the heading. Can include full HTML or just
 *   plain text - plain text will automatically be enclosed in the appropriate
 *   heading tags.
 * @param array $attributes ?
 * @todo Finish documenting this function
 */
function print_side_block_start($heading='', $attributes = array()) {

    global $CFG, $THEME;

    // If there are no special attributes, give a default CSS class
    if (empty($attributes) || !is_array($attributes)) {
        $attributes = array('class' => 'sideblock');

    } else if(!isset($attributes['class'])) {
        $attributes['class'] = 'sideblock';

    } else if(!strpos($attributes['class'], 'sideblock')) {
        $attributes['class'] .= ' sideblock';
    }

    // OK, the class is surely there and in addition to anything
    // else, it's tagged as a sideblock

    /*

    // IE misery: if I do it this way, blocks which start hidden cannot be "unhidden"

    // If there is a cookie to hide this thing, start it hidden
    if (!empty($attributes['id']) && isset($_COOKIE['hide:'.$attributes['id']])) {
        $attributes['class'] = 'hidden '.$attributes['class'];
    }
    */

    $attrtext = '';
    foreach ($attributes as $attr => $val) {
        $attrtext .= ' '.$attr.'="'.$val.'"';
    }

    echo '';

    if (!empty($THEME->customcorners)) {
        echo ''."\n";
    }
    if ($heading) {
        // Some callers pass in complete html for the heading, which may include
        // complicated things such as the 'hide block' button; some just pass in
        // text. If they only pass in plain text i.e. it doesn't include a
        // , then we add in standard tags that make it look like a normal
        // page block including the h2 for accessibility
        if(strpos($heading,'')===false) {
            $heading=''.$heading.'';
        }

        echo '';
        if (!empty($THEME->customcorners)) {
            echo ' ';
            echo '';
            echo '';
        }
        echo $heading;
        if (!empty($THEME->customcorners)) {
            echo '';
        }
        echo '';
    } else {
        if (!empty($THEME->customcorners)) {
            echo ' ';
        }
    }

    if (!empty($THEME->customcorners)) {
        echo '';
        echo '';
    }
    echo '';

}


/**
 * Print table ending tags for a side block box.
 */
function print_side_block_end($attributes = array(), $title='') {
    global $CFG, $THEME;

    echo '';

    if (!empty($THEME->customcorners)) {
        echo ' ';
    }

    echo '';

    $strshow = addslashes_js(get_string('showblocka', 'access', strip_tags($title)));
    $strhide = addslashes_js(get_string('hideblocka', 'access', strip_tags($title)));

    // IE workaround: if I do it THIS way, it works! WTF?
    if (!empty($CFG->allowuserblockhiding) && isset($attributes['id'])) {
        echo '';
    }

}


function page_id_and_class(&$getid, &$getclass) {
    // Create class and id for this page
    global $CFG, $ME;

    static $class = NULL;
    static $id    = NULL;

    if (empty($CFG->pagepath)) {
        $CFG->pagepath = $ME;
    }

    if (empty($class) || empty($id)) {
        $path = str_replace($CFG->httpswwwroot.'/', '', $CFG->pagepath);  //Because the page could be HTTPSPAGEREQUIRED
        $path = str_replace('.php', '', $path);
        if (substr($path, -1) == '/') {
            $path .= 'index';
        }
        if (empty($path) || $path == 'index') {
            $id    = 'site-index';
            $class = 'course';
        } else if (substr($path, 0, 5) == 'admin') {
            $id    = str_replace('/', '-', $path);
            $class = 'admin';
        } else {
            $id    = str_replace('/', '-', $path);
            $class = explode('-', $id);
            array_pop($class);
            $class = implode('-', $class);
        }
    }

    $getid    = $id;
    $getclass = $class;
}

/**
 * Prints a maintenance message from /maintenance.html
 */
function print_maintenance_message () {
    global $CFG, $SITE;

    $CFG->pagepath = "index.php";
    print_header(strip_tags($SITE->fullname), $SITE->fullname, 'home');
    print_box_start();
    print_heading(get_string('sitemaintenance', 'admin'));
    @include($CFG->dataroot.'/1/maintenance.html');
    print_box_end();
    print_footer();
}

/**
 * Adjust the list of allowed tags based on $CFG->allowobjectembed and user roles (admin)
 */
function adjust_allowed_tags() {

    global $CFG, $ALLOWED_TAGS;

    if (!empty($CFG->allowobjectembed)) {
        $ALLOWED_TAGS .= '';
    }
}

/// Some code to print tabs

/// A class for tabs
class tabobject {
    var $id;
    var $link;
    var $text;
    var $linkedwhenselected;

    /// A constructor just because I like constructors
    function tabobject ($id, $link='', $text='', $title='', $linkedwhenselected=false) {
        $this->id   = $id;
        $this->link = $link;
        $this->text = $text;
        $this->title = $title ? $title : $text;
        $this->linkedwhenselected = $linkedwhenselected;
    }
}



/**
 * Returns a string containing a nested list, suitable for formatting into tabs with CSS.
 *
 * @param array $tabrows An array of rows where each row is an array of tab objects
 * @param string $selected  The id of the selected tab (whatever row it's on)
 * @param array  $inactive  An array of ids of inactive tabs that are not selectable.
 * @param array  $activated An array of ids of other tabs that are currently activated
**/
function print_tabs($tabrows, $selected=NULL, $inactive=NULL, $activated=NULL, $return=false) {
    global $CFG;

/// $inactive must be an array
    if (!is_array($inactive)) {
        $inactive = array();
    }

/// $activated must be an array
    if (!is_array($activated)) {
        $activated = array();
    }

/// Convert the tab rows into a tree that's easier to process
    if (!$tree = convert_tabrows_to_tree($tabrows, $selected, $inactive, $activated)) {
        return false;
    }

/// Print out the current tree of tabs (this function is recursive)

    $output = convert_tree_to_html($tree);

    $output = "\n\n".''.$output.' '."\n\n";

/// We're done!

    if ($return) {
        return $output;
    }
    echo $output;
}


function convert_tree_to_html($tree, $row=0) {

    $str = "\n".''."\n";

    $first = true;
    $count = count($tree);

    foreach ($tree as $tab) {
        $count--;   // countdown to zero

        $liclass = '';

        if ($first && ($count == 0)) {   // Just one in the row
            $liclass = 'first last';
            $first = false;
        } else if ($first) {
            $liclass = 'first';
            $first = false;
        } else if ($count == 0) {
            $liclass = 'last';
        }

        if ((empty($tab->subtree)) && (!empty($tab->selected))) {
            $liclass .= (empty($liclass)) ? 'onerow' : ' onerow';
        }

        if ($tab->inactive || $tab->active || $tab->selected) {
            if ($tab->selected) {
                $liclass .= (empty($liclass)) ? 'here selected' : ' here selected';
            } else if ($tab->active) {
                $liclass .= (empty($liclass)) ? 'here active' : ' here active';
            }
        }

        $str .= (!empty($liclass)) ? '' : '';

        if ($tab->inactive || $tab->active || ($tab->selected && !$tab->linkedwhenselected)) {
            // The a tag is used for styling
            $str .= ''.$tab->text.'';
        } else {
            $str .= ''.$tab->text.'';
        }

        if (!empty($tab->subtree)) {
            $str .= convert_tree_to_html($tab->subtree, $row+1);
        } else if ($tab->selected) {
            $str .= ' '."\n";
        }

        $str .= ' '."\n";
    }
    $str .= ''."\n";

    return $str;
}


function convert_tabrows_to_tree($tabrows, $selected, $inactive, $activated) {

/// Work backwards through the rows (bottom to top) collecting the tree as we go.

    $tabrows = array_reverse($tabrows);

    $subtree = array();

    foreach ($tabrows as $row) {
        $tree = array();

        foreach ($row as $tab) {
            $tab->inactive = in_array((string)$tab->id, $inactive);
            $tab->active = in_array((string)$tab->id, $activated);
            $tab->selected = (string)$tab->id == $selected;

            if ($tab->active || $tab->selected) {
                if ($subtree) {
                    $tab->subtree = $subtree;
                }
            }
            $tree[] = $tab;
        }
        $subtree = $tree;
    }

    return $subtree;
}


/**
 * Returns a string containing a link to the user documentation for the current
 * page. Also contains an icon by default. Shown to teachers and admin only.
 *
 * @param string $text      The text to be displayed for the link
 * @param string $iconpath  The path to the icon to be displayed
 */
function page_doc_link($text='', $iconpath='') {
    global $ME, $COURSE, $CFG;

    if (empty($CFG->docroot) or empty($CFG->rolesactive)) {
        return '';
    }

    if (empty($COURSE->id)) {
        $context = get_context_instance(CONTEXT_SYSTEM);
    } else {
        $context = get_context_instance(CONTEXT_COURSE, $COURSE->id);
    }

    if (!has_capability('moodle/site:doclinks', $context)) {
        return '';
    }

    if (empty($CFG->pagepath)) {
        $CFG->pagepath = $ME;
    }

    $path = str_replace($CFG->httpswwwroot.'/','', $CFG->pagepath);  // Because the page could be HTTPSPAGEREQUIRED
    $path = str_replace('.php', '', $path);

    if (empty($path)) {   // Not for home page
        return '';
    }
    return doc_link($path, $text, $iconpath);
}

/**
 * @param string $path the end of the URL.
 * @return The start of a MoodleDocs URL in the user's language.
 *      E.g. http://docs.moodle.org/en/
 */
function get_docs_url($path) {
    global $CFG;
    return $CFG->docroot . '/' . str_replace('_utf8', '', current_language()) . '/' . $path;
}

/**
 * Returns a string containing a link to the user documentation.
 * Also contains an icon by default. Shown to teachers and admin only.
 *
 * @param string $path      The page link after doc root and language, no
 *                              leading slash.
 * @param string $text      The text to be displayed for the link
 * @param string $iconpath  The path to the icon to be displayed
 */
function doc_link($path='', $text='', $iconpath='') {
    global $CFG;

    if (empty($CFG->docroot)) {
        return '';
    }

    $url = get_docs_url($path);

    $target = '';
    if (!empty($CFG->doctonewwindow)) {
        $target = " onclick=\"window.open('$url'); return false;\"";
    }

    $str = "";

    if (empty($iconpath)) {
        $iconpath = $CFG->httpswwwroot . '/pix/docs.gif';
    }

    // alt left blank intentionally to prevent repetition in screenreaders
    $str .= '' .$text. '';

    return $str;
}


/**
 * Returns true if the current site debugging settings are equal or above specified level.
 * If passed a parameter it will emit a debugging notice similar to trigger_error(). The
 * routing of notices is controlled by $CFG->debugdisplay
 * eg use like this:
 *
 * 1)  debugging('a normal debug notice');
 * 2)  debugging('something really picky', DEBUG_ALL);
 * 3)  debugging('annoying debug message only for develpers', DEBUG_DEVELOPER);
 * 4)  if (debugging()) { perform extra debugging operations (do not use print or echo) }
 *
 * In code blocks controlled by debugging() (such as example 4)
 * any output should be routed via debugging() itself, or the lower-level
 * trigger_error() or error_log(). Using echo or print will break XHTML
 * JS and HTTP headers.
 *
 *
 * @param string $message a message to print
 * @param int $level the level at which this debugging statement should show
 * @param array $backtrace use different backtrace
 * @return bool
 */
function debugging($message='', $level=DEBUG_NORMAL, $backtrace=null) {

    global $CFG;

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

    if ($CFG->debug >= $level) {
        if ($message) {
            if (!$backtrace) {
                $backtrace = debug_backtrace();
            }
            $from = print_backtrace($backtrace, true);
            if (!isset($CFG->debugdisplay)) {
                $CFG->debugdisplay = ini_get_bool('display_errors');
            }
            if ($CFG->debugdisplay) {
                if (!defined('DEBUGGING_PRINTED')) {
                    define('DEBUGGING_PRINTED', 1); // indicates we have printed something
                }
                notify($message . $from, 'notifytiny');
            } else {
                trigger_error($message . $from, E_USER_NOTICE);
            }
        }
        return true;
    }
    return false;
}

/**
 * Prints formatted backtrace
 * @param backtrace array
 * @param return return as string or print
 * @return mixed
 */
function print_backtrace($callers, $return=false) {
    global $CFG;

    $from = '';
    foreach ($callers as $caller) {
        if (!isset($caller['line'])) {
            $caller['line'] = '?'; // probably call_user_func()
        }
        if (!isset($caller['file'])) {
            $caller['file'] = $CFG->dirroot.'/unknownfile'; // probably call_user_func()
        }
        $from .= 'line ' . $caller['line'] . ' of ' . substr($caller['file'], strlen($CFG->dirroot) + 1);
        if (isset($caller['function'])) {
            $from .= ': call to ';
            if (isset($caller['class'])) {
                $from .= $caller['class'] . $caller['type'];
            }
            $from .= $caller['function'] . '()';
        } else if (isset($caller['exception'])) {
            $from .= ': '.$caller['exception'].' thrown';
        }
        $from .= '';
    }
    $from .= '';

    if ($return) {
        return $from;
    } else {
        echo $from;
    }
}

/**
 * Disable debug messages from debugging(), while keeping PHP error reporting level as is.
 */
function disable_debugging() {
    global $CFG;
    $CFG->debug = $CFG->debug | 0x80000000; // switch the sign bit in integer number ;-)
}


/**
 *  Returns string to add a frame attribute, if required
 */
function frametarget() {
    global $CFG;

    if (empty($CFG->framename) or ($CFG->framename == '_top')) {
        return '';
    } else {
        return ' target="'.$CFG->framename.'" ';
    }
}

/**
* Outputs a HTML comment to the browser. This is used for those hard-to-debug
* pages that use bits from many different files in very confusing ways (e.g. blocks).
* @usage print_location_comment(__FILE__, __LINE__);
* @param string $file
* @param integer $line
* @param boolean $return Whether to return or print the comment
* @return mixed Void unless true given as third parameter
*/
function print_location_comment($file, $line, $return = false)
{
    if ($return) {
        return "\n";
    } else {
        echo "\n";
    }
}


/**
 * Returns an image of an up or down arrow, used for column sorting. To avoid unnecessary DB accesses, please
 * provide this function with the language strings for sortasc and sortdesc.
 * If no sort string is associated with the direction, an arrow with no alt text will be printed/returned.
 * @param string $direction 'up' or 'down'
 * @param string $strsort The language string used for the alt attribute of this image
 * @param bool $return Whether to print directly or return the html string
 * @return string HTML for the image
 *
 * TODO See if this isn't already defined somewhere. If not, move this to weblib
 */
function print_arrow($direction='up', $strsort=null, $return=false) {
    global $CFG;

    if (!in_array($direction, array('up', 'down', 'right', 'left', 'move'))) {
        return null;
    }

    $return = null;

    switch ($direction) {
        case 'up':
            $sortdir = 'asc';
            break;
        case 'down':
            $sortdir = 'desc';
            break;
        case 'move':
            $sortdir = 'asc';
            break;
        default:
            $sortdir = null;
            break;
    }

    // Prepare language string
    $strsort = '';
    if (empty($strsort) && !empty($sortdir)) {
        $strsort  = get_string('sort' . $sortdir, 'grades');
    }

    $return = '  ';

    if ($return) {
        return $return;
    } else {
        echo $return;
    }
}

/**
 * Returns boolean true if the current language is right-to-left (Hebrew, Arabic etc)
 *
 */
function right_to_left() {
    static $result;

    if (isset($result)) {
        return $result;
    }
    return $result = (get_string('thisdirection') == 'rtl');
}


/**
 * Returns swapped left<=>right if in RTL environment.
 * part of RTL support
 *
 * @param string $align align to check
 * @return string
 */
function fix_align_rtl($align) {
    if (!right_to_left()) {
        return $align;
    }
    if ($align=='left')  { return 'right'; }
    if ($align=='right') { return 'left'; }
    return $align;
}


/**
 * Returns true if the page is displayed in a popup window.
 * Gets the information from the URL parameter inpopup.
 *
 * @return boolean
 *
 * TODO Use a central function to create the popup calls allover Moodle and
 * TODO In the moment only works with resources and probably questions.
 */
function is_in_popup() {
    $inpopup = optional_param('inpopup', '', PARAM_BOOL);

    return ($inpopup);
}
class progress_bar {
    private $html_id;
    private $percent;
    private $width;
    private $clr;
    private $lastcall;
    private $time_start;
    private $minimum_time = 2; //min time between updates.
    function __construct($html_id = 'pid', $width = 500, $autostart = false){
        $this->html_id  = $html_id;
        $this->clr      = new stdClass;
        $this->clr->done    = 'green';
        $this->clr->process = '#FFCC66';
        $this->width = $width;
        $this->restart();
        if($autostart){
            $this->create();
        }
    }
    /**
      * set progress bar color, call before $this->create
      * Usage:
      *     $clr->done = 'red';
      *     $clr->process = 'blue';
      *     $pb->setclr($clr);
      *     $pb->create();
      *     ......
      *
      * @param $clr object
      */
    function setclr($clr){
        foreach($clr as $n=>$v) {
            $this->clr->$n = $v;
        }
    }
    /**
      * Create a new progress bar, this function will output
      * html.
      *
      */
    function create(){
            flush();
            $this->lastcall->pt = 0;
            $this->lastcall->time = microtime(true);
            $htmlcode = <<
            Number.prototype.fixed=function(n){
                with(Math)
                    return round(Number(this)*pow(10,n))/pow(10,n);
            }
            function up_{$this->html_id} (id, width, pt, msg, es){
                percent = pt*100;
                document.getElementById("status_"+id).innerHTML = msg;
                document.getElementById("pt_"+id).innerHTML =
                    percent.fixed(2) + '%';
                if(percent == 100) {
                    document.getElementById("progress_"+id).style.background
                        = "{$this->clr->done}";
                    document.getElementById("time_"+id).style.display
                            = "none";
                } else {
                    document.getElementById("progress_"+id).style.background
                        = "{$this->clr->process}";
                    if (es == Infinity){
                        document.getElementById("time_"+id).innerHTML =
                            "Initializing...";
                    }else {
                        document.getElementById("time_"+id).innerHTML =
                            es.fixed(2)+" sec";
                        document.getElementById("time_"+id).style.display
                            = "block";
                    }
                }
                document.getElementById("progress_"+id).style.width
                    = width + "px";

            }

            
            
                
                
                
                     
                    
                
            
EOT;
            echo $htmlcode;
            flush();
    }
    function _update($percent, $msg, $es){
        if(empty($this->time_start)){
            $this->time_start = microtime(true);
        }
        $this->percent = $percent;
        $this->lastcall->time = microtime(true);
        $this->lastcall->pt   = $percent;
        $w = $this->percent * $this->width;
        if ($es === null){
            $es = "Infinity";
        }
        echo "";
        flush();
    }
    /**
      * estimate time
      *
      * @param $curtime int the time call this function
      * @param $percent int
      */
    function estimate($curtime, $pt){
        $consume = $curtime - $this->time_start;
        $one = $curtime - $this->lastcall->time;
        $this->percent = $pt;
        $percent = $pt - $this->lastcall->pt;
        if($percent != 0)
            $left = ($one / $percent) - $consume;
        else
            return null;
        if($left < 0)
            return 0;
        else
            return $left;
    }
    /**
      * Update progress bar according percent
      *
      * @param $percent int from 1-100
      * @param $msg     string the message needed to be shown
      */
    function update_full($percent, $msg){
        $percent = max(min($percent, 100), 0);
        if ($percent != 100 && ($this->lastcall->time + $this->minimum_time) > microtime(true)){
            return;
        }
        $this->_update($percent/100, $msg);
    }
    /**
      * Update progress bar according the nubmer of tasks
      *
      * @param $cur   int       current task number
      * @param $total int       total task number
      * @param $msg   string    message
      */
    function update($cur, $total, $msg){
        $cur = max($cur, 0);
        if ($cur >= $total){
            $percent = 1;
        } else {
            $percent = $cur / $total;
        }
        /**
        if ($percent != 1 && ($this->lastcall->time + $this->minimum_time) > microtime(true)){
            return;
        }
        */
        $es = $this->estimate(microtime(true), $percent);
        $this->_update($percent, $msg, $es);
    }
    /**
     * Restart the progress bar.
     */
    function restart(){
        $this->percent  = 0;
        $this->lastcall = new stdClass;
        $this->lastcall->pt = 0;
        $this->lastcall->time = microtime(true);
        $this->time_start  = 0;
    }
}

// vim:autoindent:expandtab:shiftwidth=4:tabstop=4:tw=140:
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