[moodle.git] / lib / formslib.php

<?php // $Id$
/**
 * formslib.php - library of classes for creating forms in Moodle, based on PEAR QuickForms.
 *
 * To use formslib then you will want to create a new file purpose_form.php eg. edit_form.php
 * and you want to name your class something like {modulename}_{purpose}_form. Your class will
 * extend moodleform overriding abstract classes definition and optionally defintion_after_data
 * and validation.
 *
 * See examples of use of this library in course/edit.php and course/edit_form.php
 *
 * A few notes :
 *      form defintion is used for both printing of form and processing and should be the same
 *              for both or you may lose some submitted data which won't be let through.
 *      you should be using setType for every form element except select, radio or checkbox
 *              elements, these elements clean themselves.
 *
 *
 * @author  Jamie Pratt
 * @version $Id$
 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
 */

//point pear include path to moodles lib/pear so that includes and requires will search there for files before anywhere else.
if (FALSE===strstr(ini_get('include_path'), $CFG->libdir.'/pear' )){
    ini_set('include_path', $CFG->libdir.'/pear' . PATH_SEPARATOR . ini_get('include_path'));
}
require_once 'HTML/QuickForm.php';
require_once 'HTML/QuickForm/DHTMLRulesTableless.php';
require_once 'HTML/QuickForm/Renderer/Tableless.php';

require_once $CFG->libdir.'/uploadlib.php';

define('FORM_ADVANCEDIMAGEURL', $CFG->wwwroot.'/lib/form/adv.gif');
define('FORM_REQIMAGEURL', $CFG->wwwroot.'/lib/form/req.gif');

if ($CFG->debug >= DEBUG_ALL){
    PEAR::setErrorHandling(PEAR_ERROR_PRINT);
}

/**
 * Moodle specific wrapper that separates quickforms syntax from moodle code. You won't directly
 * use this class you should write a class defintion which extends this class or a more specific
 * subclass such a moodleform_mod for each form you want to display and/or process with formslib.
 *
 * You will write your own definition() method which performs the form set up.
 */
class moodleform {
    var $_formname;       // form name
    /**
     * quickform object definition
     *
     * @var MoodleQuickForm
     */
    var $_form;
    /**
     * globals workaround
     *
     * @var array
     */
    var $_customdata;
    /**
     * file upload manager
     *
     * @var upload_manager
     */
    var $_upload_manager; //


    /**
     * The constructor function calls the abstract function definition() and it will then
     * process and clean and attempt to validate incoming data.
     *
     * It will call your custom validate method to validate data and will also check any rules
     * you have specified in definition using addRule
     *
     * The name of the form (id attribute of the form) is automatically generated depending on
     * the name you gave the class extending moodleform. You should call your class something
     * like
     *
     * @param string $action the action attribute for the form.
     * @param array $customdata if your form defintion method needs access to data such as $course
     *               $cm, etc. to construct the form definition then pass it in this array. You can
     *               use globals for somethings.
     * @param string $method if you set this to anything other than 'post' then _GET and _POST will
     *               be merged and used as incoming data to the form.
     * @param string $target target frame for form submission. You will rarely use this. Don't use
     *                  it if you don't need to as the target attribute is deprecated in xhtml
     *                  strict.
     * @param mixed $attributes you can pass a string of html attributes here or an array.
     * @return moodleform
     */
    function moodleform($action, $customdata=null, $method='post', $target='', $attributes=null) {
        //strip '_form' from the end of class name to make form 'id' attribute.
        $this->_formname = preg_replace('/_form$/', '', get_class($this), 1);
        $this->_customdata = $customdata;
        $this->_form =& new MoodleQuickForm($this->_formname, $method, $action, $target, $attributes);

        $this->definition();

        $this->_form->addElement('hidden', 'sesskey', null); // automatic sesskey protection
        $this->_form->setDefault('sesskey', sesskey());
        $this->_form->addElement('hidden', '_qf__'.$this->_formname, null);   // form submission marker
        $this->_form->setDefault('_qf__'.$this->_formname, 1);
        $this->_form->_setDefaultRuleMessages();

        // we have to know all input types before processing submission ;-)
        $this->_process_submission($method);

        // update form definition based on final data
        $this->definition_after_data();
    }

    /**
     * To autofocus on first form element or first element with error.
     *
     * @return string  javascript to select form element with first error or
     *                  first element if no errors. Use this as a parameter
     *                  when calling print_header
     */
    function focus(){
        $form =& $this->_form;
        $elkeys=array_keys($form->_elementIndex);
        if (isset($form->_errors) &&  0 != count($form->_errors)){
            $errorkeys = array_keys($form->_errors);
            $elkeys = array_intersect($elkeys, $errorkeys);
        }
        $names=null;
        while (!$names){
          $el = array_shift($elkeys);
          $names=$form->_getElNamesRecursive($el);
        }
        $name=array_shift($names);
        $focus='forms[\''.$this->_form->getAttribute('id').'\'].elements[\''.$name.'\']';
        return $focus;
     }

    /**
     * Internal method. Alters submitted data to be suitable for quickforms processing.
     * Must be called when the form is fully set up.
     */
    function _process_submission($method) {
        $submission = array();
        if ($method == 'post') {
            if (!empty($_POST)) {
                $submission = $_POST;
            }
        } else {
            $submission = array_merge_recursive($_GET, $_POST); // emulate handling of parameters in xxxx_param()
        }

        // following trick is needed to enable proper sesskey checks when using GET forms
        // the _qf__.$this->_formname serves as a marker that form was actually submitted
        if (array_key_exists('_qf__'.$this->_formname, $submission) and $submission['_qf__'.$this->_formname] == 1) {
            if (!confirm_sesskey()) {
                error('Incorrect sesskey submitted, form not accepted!');
            }
            $files = $_FILES;
        } else {
            $submission = array();
            $files = array();
        }

        $this->_form->updateSubmission($submission, $files);
    }

    /**
     * Internal method. Validates all uploaded files.
     */
    function _validate_files() {
        if (empty($_FILES)) {
            // we do not need to do any checks because no files were submitted
            // TODO: find out why server side required rule does not work for uploaded files;
            //       testing is easily done by always returning true from this function and adding
            //       $mform->addRule('soubor', get_string('required'), 'required', null, 'server');
            //       and submitting form without selected file
            return true;
        }
        $errors = array();
        $mform =& $this->_form;

        // create default upload manager if not already created
        if (empty($this->_upload_manager)) {
            $this->_upload_manager = new upload_manager();
        }

        // check the files
        $status = $this->_upload_manager->preprocess_files();

        // now check that we really want each file
        foreach ($_FILES as $elname=>$file) {
            if ($mform->elementExists($elname) and $mform->getElementType($elname)=='file') {
                $required = $mform->isElementRequired($elname);
                if (!empty($this->_upload_manager->files[$elname]['uploadlog']) and empty($this->_upload_manager->files[$elname]['clear'])) {
                    if (!$required and $file['error'] == UPLOAD_ERR_NO_FILE) {
                        // file not uploaded and not required - ignore it
                        continue;
                    }
                    $errors[$elname] = $this->_upload_manager->files[$elname]['uploadlog'];
                }
            } else {
                error('Incorrect upload attemp!');
            }
        }

        // return errors if found
        if ($status and 0 == count($errors)){
            return true;
        } else {
            return $errors;
        }
    }

    /**
     * Load in existing data as form defaults. Usually new entry defaults are stored directly in
     * form definition (new entry form); this function is used to load in data where values
     * already exist and data is being edited (edit entry form).
     *
     * @param mixed $default_values object or array of default values
     * @param bool $slased true if magic quotes applied to data values
     */
    function set_defaults($default_values, $slashed=false) {
        if (is_object($default_values)) {
            $default_values = (array)$default_values;
        }
        $filter = $slashed ? 'stripslashes' : NULL;
        $this->_form->setDefaults($default_values, $filter);
        //update form definition when data changed
        $this->definition_after_data();
    }

    /**
     * Set maximum allowed uploaded file size.
     * Must be used BEFORE creating of file element!
     *
     * @param object $course
     * @param object $modbytes - max size limit defined in module
     */
    function set_max_file_size($course=null, $modbytes=0) {
        global $CFG, $COURSE;

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

        $maxbytes = get_max_upload_file_size($CFG->maxbytes, $course->maxbytes, $modbytes);
        $this->_form->setMaxFileSize($maxbytes);
    }

    /**
     * Check that form was submitted. Does not check validity of submitted data.
     *
     * @return bool true if form properly submitted
     */
    function is_submitted() {
        return $this->_form->isSubmitted();
    }

    /**
     * Check that form data is valid.
     *
     * @return bool true if form data valid
     */
    function is_validated() {
        static $validated = null; // one validation is enough
        $mform =& $this->_form;
        foreach ($mform->_noSubmitButtons as $nosubmitbutton){
            if (optional_param($nosubmitbutton, 0, PARAM_RAW)){
                return false;
            }
        }
        if ($validated === null) {
            $internal_val = $mform->validate();
            $moodle_val = $this->validation($mform->exportValues(null, true));
            if ($moodle_val !== true) {
                if (!empty($moodle_val)) {
                    foreach ($moodle_val as $element=>$msg) {
                        $mform->setElementError($element, $msg);
                    }
                }
                $moodle_val = false;
            }
            $file_val = $this->_validate_files();
            if ($file_val !== true) {
                if (!empty($file_val)) {
                    foreach ($file_val as $element=>$msg) {
                        $mform->setElementError($element, $msg);
                    }
                }
                $file_val = false;
            }
            $validated = ($internal_val and $moodle_val and $file_val);
        }
        return $validated;
    }

    /**
     * Return true if a cancel button has been pressed resulting in the form being submitted.
     *
     * @return boolean true if a cancel button has been pressed
     */
    function is_cancelled(){
        $mform =& $this->_form;
        foreach ($mform->_cancelButtons as $cancelbutton){
            if (optional_param($cancelbutton, 0, PARAM_RAW)){
                return true;
            }
        }
        return false;
    }

    /**
     * Return submitted data if properly submitted or returns NULL if validation fails or
     * if there is no submitted data.
     *
     * @param bool $slashed true means return data with addslashes applied
     * @return object submitted data; NULL if not valid or not submitted
     */
    function data_submitted($slashed=true) {
        $mform =& $this->_form;

        if ($this->is_submitted() and $this->is_validated()) {
            $data = $mform->exportValues(null, $slashed);
            unset($data['sesskey']); // we do not need to return sesskey
            unset($data['_qf__'.$this->_formname]);   // we do not need the submission marker too
            if (empty($data)) {
                return NULL;
            } else {
                return (object)$data;
            }
        } else {
            return NULL;
        }
    }

    /**
     * Save verified uploaded files into directory. Upload process can be customised from definition()
     * method by creating instance of upload manager and storing it in $this->_upload_form
     *
     * @param string $destination where to store uploaded files
     * @return bool success
     */
    function save_files($destination) {
        if (empty($this->_upload_manager)) {
            return false;
        }
        if ($this->is_submitted() and $this->is_validated()) {
            return $this->_upload_manager->save_files($destination);
        }
        return false;
    }

    /**
     * Print html form.
     */
    function display() {
        $this->_form->display();
    }

    /**
     * Abstract method - always override!
     *
     * If you need special handling of uploaded files, create instance of $this->_upload_manager here.
     */
    function definition() {
        error('Abstract form_definition() method in class '.get_class($this).' must be overriden, please fix the code.');
    }

    /**
     * Dummy stub method - override if you need to setup the form depending on current
     * values. This method is called after definition(), data submission and set_defaults().
     * All form setup that is dependent on form values should go in here.
     */
    function definition_after_data(){
    }

    /**
     * Dummy stub method - override if you needed to perform some extra validation.
     * If there are errors return array of errors ("fieldname"=>"error message"),
     * otherwise true if ok.
     *
     * @param array $data array of ("fieldname"=>value) of submitted data
     * @return bool array of errors or true if ok
     */
    function validation($data) {
        return true;
    }


    /**
     * Method to add a repeating group of elements to a form.
     *
     * @param array $elementobjs Array of elements or groups of elements that are to be repeated
     * @param integer $repeats no of times to repeat elements initially
     * @param array $options Array of options to apply to elements. Array keys are element names.
     *                      This is an array of arrays. The second sets of keys are the option types
     *                      for the elements :
     *                          'default' - default value is value
     *                          'type' - PARAM_* constant is value
     *                          'helpbutton' - helpbutton params array is value
     *                          'disabledif' - last three moodleform::disabledIf()
     *                                           params are value as an array
     * @param string $repeathiddenname name for hidden element storing no of repeats in this form
     * @param string $addfieldsname name for button to add more fields
     * @param int $addfieldsno how many fields to add at a time
     * @param array $addstring array of params for get_string for name of button, $a is no of fields that
     *                                  will be added.
     */
    function repeat_elements($elementobjs, $repeats, $options, $repeathiddenname, $addfieldsname, $addfieldsno=5, $addstring=array('addfields', 'form')){
        $repeats = optional_param($repeathiddenname, $repeats, PARAM_INT);
        $addfields = optional_param($addfieldsname, '', PARAM_TEXT);
        if (!empty($addfields)){
            $repeats += $addfieldsno;
        }
        $mform =& $this->_form;
        $mform->_registerNoSubmitButton($addfieldsname);
        $mform->addElement('hidden', $repeathiddenname, $repeats);
        //value not to be overridden by submitted value
        $mform->setConstants(array($repeathiddenname=>$repeats));
        for ($i=0; $i<$repeats; $i++) {
            foreach ($elementobjs as $elementobj){
                $elementclone=clone($elementobj);
                $name=$elementclone->getName();
                $elementclone->setName($name."[$i]");
                if (is_a($elementclone, 'HTML_QuickForm_header')){
                    $value=$elementclone->_text;
                    $elementclone->setValue($value.' '.($i+1));

                }
                $mform->addElement($elementclone);
            }
        }
        for ($i=0; $i<$repeats; $i++) {
            foreach ($options as $elementname => $elementoptions){
                $pos=strpos($elementname, '[');
                if ($pos!==FALSE){
                    $realelementname = substr($elementname, 0, $pos+1)."[$i]";
                    $realelementname .= substr($elementname, $pos+1);
                }else {
                    $realelementname = $elementname."[$i]";
                }
                foreach ($elementoptions as  $option => $params){

                    switch ($option){
                        case 'default' :
                            $mform->setDefault($realelementname, $params);
                            break;
                        case 'type' :
                            $mform->setType($realelementname, $params);
                            break;
                        case 'helpbutton' :
                            $mform->setHelpButton($realelementname, $params);
                            break;
                        case 'disabledif' :
                            $mform->disabledIf($realelementname, $params[0], $params[1], $params[2]);
                            break;

                    }
                }
            }
        }
        $mform->addElement('submit', $addfieldsname, get_string('addfields', 'form', $addfieldsno),
                            array('onclick'=>'skipClientValidation = true; return true;'));//need this to bypass client validation

        $renderer =& $mform->defaultRenderer();
        $renderer->addStopFieldsetElements($addfieldsname);
        return $repeats;
    }
}

/**
 * You never extend this class directly. The class methods of this class are available from
 * the private $this->_form property on moodleform and it's children. You generally only
 * call methods on this class from within abstract methods that you override on moodleform such
 * as definition and definition_after_data
 *
 */
class MoodleQuickForm extends HTML_QuickForm_DHTMLRulesTableless {
    var $_types = array();
    var $_dependencies = array();
    /**
     * Array of buttons that if pressed do not result in the processing of the form.
     *
     * @var array
     */
    var $_noSubmitButtons=array();
    /**
     * Array of buttons that if pressed do not result in the processing of the form.
     *
     * @var array
     */
    var $_cancelButtons=array();

    /**
     * Array whose keys are element names. If the key exists this is a advanced element
     *
     * @var array
     */
    var $_advancedElements = array();

    /**
     * Whether to display advanced elements (on page load)
     *
     * @var boolean
     */
    var $_showAdvanced = null;

    /**
     * Class constructor - same parameters as HTML_QuickForm_DHTMLRulesTableless
     * @param    string      $formName          Form's name.
     * @param    string      $method            (optional)Form's method defaults to 'POST'
     * @param    string      $action            (optional)Form's action
     * @param    string      $target            (optional)Form's target defaults to none
     * @param    mixed       $attributes        (optional)Extra attributes for <form> tag
     * @param    bool        $trackSubmit       (optional)Whether to track if the form was submitted by adding a special hidden field
     * @access   public
     */
    function MoodleQuickForm($formName, $method, $action, $target='', $attributes=null){
        global $CFG;

        HTML_Common::HTML_Common($attributes);
        $target = empty($target) ? array() : array('target' => $target);
        //no 'name' atttribute for form in xhtml strict :
        $attributes = array('action'=>$action, 'method'=>$method, 'id'=>$formName) + $target;
        $this->updateAttributes($attributes);

        //this is custom stuff for Moodle :
        $oldclass=   $this->getAttribute('class');
        if (!empty($oldclass)){
            $this->updateAttributes(array('class'=>$oldclass.' mform'));
        }else {
            $this->updateAttributes(array('class'=>'mform'));
        }
        $this->_reqHTML = '<img alt="'.get_string('requiredelement', 'form').'" src="'.FORM_REQIMAGEURL.'" />';
        $this->_advancedHTML = '<img alt="'.get_string('advancedelement', 'form').'" src="'.FORM_ADVANCEDIMAGEURL.'" />';
        $this->setRequiredNote(get_string('denotesreq', 'form',
            helpbutton('requiredelement', get_string('requiredelement', 'form'),'moodle',
                 true, false, '', true, '<img alt="'.get_string('requiredelement', 'form').'" src="'.
            FORM_REQIMAGEURL.'" />')));
    }

    function setShowAdvanced($showadvancedNow){
        $this->_showAdvanced=$showadvancedNow;
    }
    function getShowAdvanced(){
        return $this->_showAdvanced;
    }

    /**
     * Adds an element into the form
     *
     * If $element is a string representing element type, then this
     * method accepts variable number of parameters, their meaning
     * and count depending on $element
     *
     * @param    mixed      $element        element object or type of element to add (text, textarea, file...)
     * @since    1.0
     * @return   object     reference to element
     * @access   public
     * @throws   HTML_QuickForm_Error
     */
    function addElement($element)
    {
        //call parent with a variable ammount of arguments
        $args = func_get_args();
        $parent_name = get_parent_class($this);
        //static method call

        return call_user_func_array(array($parent_name, 'addElement'), $args);
    }

   /**
    * Accepts a renderer
    *
    * @param HTML_QuickForm_Renderer  An HTML_QuickForm_Renderer object
    * @since 3.0
    * @access public
    * @return void
    */
    function accept(&$renderer)
    {
        if (method_exists($renderer, 'setAdvancedElements')){
            //check for visible fieldsets where all elements are advanced
            //and mark these headers as advanced as well.
            //And mark all elements in a advanced header as advanced
            $stopFields = $renderer->getStopFieldSetElements();
            $lastHeader = null;
            $lastHeaderAdvanced = false;
            $anyAdvanced = false;
            foreach (array_keys($this->_elements) as $elementIndex){
                $element =& $this->_elements[$elementIndex];
                if ($element->getType()=='header' || in_array($element->getName(), $stopFields)){
                    if ($anyAdvanced && ($lastHeader!==null)){
                        $this->setAdvanced($lastHeader->getName());
                    }
                    $lastHeaderAdvanced = false;
                } elseif ($lastHeaderAdvanced) {
                    $this->setAdvanced($element->getName());
                }
                if ($element->getType()=='header'){
                    $lastHeader =& $element;
                    $anyAdvanced = false;
                    $lastHeaderAdvanced = isset($this->_advancedElements[$element->getName()]);
                } elseif (isset($this->_advancedElements[$element->getName()])){
                    $anyAdvanced = true;
                }
            }
            $renderer->setAdvancedElements($this->_advancedElements);
            if (count($this->_advancedElements)){

            }
        }
        parent::accept($renderer);
    }

    function setAdvanced($elementName, $advanced=true){
        if ($advanced){
            $this->_advancedElements[$elementName]='';
        } elseif (isset($this->_advancedElements[$elementName])) {
            unset($this->_advancedElements[$elementName]);
        }
        if ($advanced && $this->getShowAdvanced()===null){
            //hidden element
            $showadvanced_last = optional_param('mform_showadvanced_last', 0, PARAM_INT);
            //button
            $showadvanced = optional_param('mform_showadvanced', 0, PARAM_RAW);
            //toggle if button pressed or else stay the same
            if ($showadvanced && $showadvanced_last){
                $showadvanced_now = 0;
            } elseif ($showadvanced && !$showadvanced_last) {
                $showadvanced_now = 1;
            } else {
                $showadvanced_now = $showadvanced_last;
            }

            $this->setConstants(array('mform_showadvanced_last'=>$showadvanced_now));
            //below tells form whether to display elements or not
            $this->setShowAdvanced($showadvanced_now);
            $this->_registerNoSubmitButton('mform_showadvanced');

            $this->addElement('hidden', 'mform_showadvanced_last');
        }
    }

    function closeHeaderBefore($elementName){
        $renderer =& $this->defaultRenderer();
        $renderer->addStopFieldsetElements($elementName);
    }

    /**
     * Should be used for all elements of a form except for select, radio and checkboxes which
     * clean their own data.
     *
     * @param string $elementname
     * @param integer $paramtype use the constants PARAM_*.
     *     *  PARAM_CLEAN is deprecated and you should try to use a more specific type.
     *     *  PARAM_TEXT should be used for cleaning data that is expected to be plain text.
     *          It will strip all html tags. But will still let tags for multilang support
     *          through.
     *     *  PARAM_RAW means no cleaning whatsoever, it is used mostly for data from the
     *          html editor. Data from the editor is later cleaned before display using
     *          format_text() function. PARAM_RAW can also be used for data that is validated
     *          by some other way or printed by p() or s().
     *     *  PARAM_INT should be used for integers.
     *     *  PARAM_ACTION is an alias of PARAM_ALPHA and is used for hidden fields specifying
     *          form actions.
     */
    function setType($elementname, $paramtype) {
        $this->_types[$elementname] = $paramtype;
    }

    /**
     * See description of setType above. This can be used to set several types at once.
     *
     * @param array $paramtypes
     */
    function setTypes($paramtypes) {
        $this->_types = $paramtypes + $this->_types;
    }

    function updateSubmission($submission, $files) {
        $this->_flagSubmitted = false;

        if (empty($submission)) {
            $this->_submitValues = array();
        } else {
            foreach ($submission as $key=>$s) {
                if (array_key_exists($key, $this->_types)) {
                    $submission[$key] = clean_param($s, $this->_types[$key]);
                }
            }
            $this->_submitValues = $this->_recursiveFilter('stripslashes', $submission);
            $this->_flagSubmitted = true;
        }

        if (empty($files)) {
            $this->_submitFiles = array();
        } else {
            if (1 == get_magic_quotes_gpc()) {
                foreach ($files as $elname=>$file) {
                    // dangerous characters in filenames are cleaned later in upload_manager
                    $files[$elname]['name'] = stripslashes($files[$elname]['name']);
                }
            }
            $this->_submitFiles = $files;
            $this->_flagSubmitted = true;
        }

        // need to tell all elements that they need to update their value attribute.
         foreach (array_keys($this->_elements) as $key) {
             $this->_elements[$key]->onQuickFormEvent('updateValue', null, $this);
         }
    }

    function getReqHTML(){
        return $this->_reqHTML;
    }

    function getAdvancedHTML(){
        return $this->_advancedHTML;
    }

    /**
     * Initializes a default form value. Used to specify the default for a new entry where
     * no data is loaded in using moodleform::set_defaults()
     *
     * @param     string   $elementname        element name
     * @param     mixed    $values             values for that element name
     * @param     bool     $slashed            the default value is slashed
     * @access    public
     * @return    void
     */
    function setDefault($elementName, $defaultValue, $slashed=false){
        $filter = $slashed ? 'stripslashes' : NULL;
        $this->setDefaults(array($elementName=>$defaultValue), $filter);
    } // end func setDefault
    /**
     * Add an array of buttons to the form
     * @param    array       $buttons          An associative array representing help button to attach to
     *                                          to the form. keys of array correspond to names of elements in form.
     *
     * @access   public
    */
    function setHelpButtons($buttons, $suppresscheck=false, $function='helpbutton'){

        foreach ($buttons as $elementname => $button){
            $this->setHelpButton($elementname, $button, $suppresscheck, $function);
        }
    }
    /**
     * Add a single button.
     *
     * @param string $elementname name of the element to add the item to
     * @param array $button - arguments to pass to function $function
     * @param boolean $suppresscheck - whether to throw an error if the element
     *                                  doesn't exist.
     * @param string $function - function to generate html from the arguments in $button
     */
    function setHelpButton($elementname, $button, $suppresscheck=false, $function='helpbutton'){
        if (array_key_exists($elementname, $this->_elementIndex)){
            //_elements has a numeric index, this code accesses the elements by name
            $element=&$this->_elements[$this->_elementIndex[$elementname]];
            if (method_exists($element, 'setHelpButton')){
                $element->setHelpButton($button, $function);
            }else{
                $a=new object();
                $a->name=$element->getName();
                $a->classname=get_class($element);
                print_error('nomethodforaddinghelpbutton', 'form', '', $a);
            }
        }elseif (!$suppresscheck){
            print_error('nonexistentformelements', 'form', '', $elementname);
        }
    }

    function exportValues($elementList= null, $addslashes=true){
        $unfiltered=parent::exportValues($elementList);

        if ($addslashes){
            return $this->_recursiveFilter('addslashes',$unfiltered);
        } else {
            return $unfiltered;
        }
    }
    /**
     * Returns the client side validation script
     *
     * The code here was copied from HTML_QuickForm_DHTMLRulesTableless who copied it from  HTML_QuickForm
     * and slightly modified to run rules per-element
     * Needed to override this because of an error with client side validation of grouped elements.
     *
     * @access    public
     * @return    string    Javascript to perform validation, empty string if no 'client' rules were added
     */
    function getValidationScript()
    {
        if (empty($this->_rules) || empty($this->_attributes['onsubmit'])) {
            return '';
        }

        include_once('HTML/QuickForm/RuleRegistry.php');
        $registry =& HTML_QuickForm_RuleRegistry::singleton();
        $test = array();
        $js_escape = array(
            "\r"    => '\r',
            "\n"    => '\n',
            "\t"    => '\t',
            "'"     => "\\'",
            '"'     => '\"',
            '\\'    => '\\\\'
        );

        foreach ($this->_rules as $elementName => $rules) {
            foreach ($rules as $rule) {
                if ('client' == $rule['validation']) {
                    unset($element); //TODO: find out how to properly initialize it

                    $dependent  = isset($rule['dependent']) && is_array($rule['dependent']);
                    $rule['message'] = strtr($rule['message'], $js_escape);

                    if (isset($rule['group'])) {
                        $group    =& $this->getElement($rule['group']);
                        // No JavaScript validation for frozen elements
                        if ($group->isFrozen()) {
                            continue 2;
                        }
                        $elements =& $group->getElements();
                        foreach (array_keys($elements) as $key) {
                            if ($elementName == $group->getElementName($key)) {
                                $element =& $elements[$key];
                                break;
                            }
                        }
                    } elseif ($dependent) {
                        $element   =  array();
                        $element[] =& $this->getElement($elementName);
                        foreach ($rule['dependent'] as $idx => $elName) {
                            $element[] =& $this->getElement($elName);
                        }
                    } else {
                        $element =& $this->getElement($elementName);
                    }
                    // No JavaScript validation for frozen elements
                    if (is_object($element) && $element->isFrozen()) {
                        continue 2;
                    } elseif (is_array($element)) {
                        foreach (array_keys($element) as $key) {
                            if ($element[$key]->isFrozen()) {
                                continue 3;
                            }
                        }
                    }
                    // Fix for bug displaying errors for elements in a group
                    //$test[$elementName][] = $registry->getValidationScript($element, $elementName, $rule);
                    $test[$elementName][0][] = $registry->getValidationScript($element, $elementName, $rule);
                    $test[$elementName][1]=$element;
                    //end of fix
                }
            }
        }
        $js = '
<script type="text/javascript">
//<![CDATA[

var skipClientValidation = false;

function qf_errorHandler(element, _qfMsg) {
  div = element.parentNode;
  if (_qfMsg != \'\') {
    var errorSpan = document.getElementById(\'id_error_\'+element.name);
    if (!errorSpan) {
      errorSpan = document.createElement("span");
      errorSpan.id = \'id_error_\'+element.name;
      errorSpan.className = "error";
      element.parentNode.insertBefore(errorSpan, element.parentNode.firstChild);
    }

    while (errorSpan.firstChild) {
      errorSpan.removeChild(errorSpan.firstChild);
    }

    errorSpan.appendChild(document.createTextNode(_qfMsg.substring(3)));
    errorSpan.appendChild(document.createElement("br"));

    if (div.className.substr(div.className.length - 6, 6) != " error"
        && div.className != "error") {
      div.className += " error";
    }

    return false;
  } else {
    var errorSpan = document.getElementById(\'id_error_\'+element.name);
    if (errorSpan) {
      errorSpan.parentNode.removeChild(errorSpan);
    }

    if (div.className.substr(div.className.length - 6, 6) == " error") {
      div.className = div.className.substr(0, div.className.length - 6);
    } else if (div.className == "error") {
      div.className = "";
    }

    return true;
  }
}';
        $validateJS = '';
        foreach ($test as $elementName => $jsandelement) {
            // Fix for bug displaying errors for elements in a group
            //unset($element);
            list($jsArr,$element)=$jsandelement;
            //end of fix
            $js .= '
function validate_' . $this->_attributes['id'] . '_' . $elementName . '(element) {
  var value = \'\';
  var errFlag = new Array();
  var _qfGroups = {};
  var _qfMsg = \'\';
  var frm = element.parentNode;
  while (frm && frm.nodeName != "FORM") {
    frm = frm.parentNode;
  }
' . join("\n", $jsArr) . '
  return qf_errorHandler(element, _qfMsg);
}
';
            $validateJS .= '
  ret = validate_' . $this->_attributes['id'] . '_' . $elementName.'(frm.elements[\''.$elementName.'\']) && ret;';
            // Fix for bug displaying errors for elements in a group
            //unset($element);
            //$element =& $this->getElement($elementName);
            //end of fix
            $valFunc = 'validate_' . $this->_attributes['id'] . '_' . $elementName . '(this)';
            $onBlur = $element->getAttribute('onBlur');
            $onChange = $element->getAttribute('onChange');
            $element->updateAttributes(array('onBlur' => $onBlur . $valFunc,
                                             'onChange' => $onChange . $valFunc));
        }
//  do not rely on frm function parameter, because htmlarea breaks it when overloading the onsubmit method
        $js .= '
function validate_' . $this->_attributes['id'] . '(frm) {
  if (skipClientValidation) {
     return true;
  }
  var ret = true;

  var frm = document.getElementById(\''. $this->_attributes['id'] .'\')

' . $validateJS . ';
  return ret;
}
//]]>
</script>';
        return $js;
    } // end func getValidationScript
    function _setDefaultRuleMessages(){
        foreach ($this->_rules as $field => $rulesarr){
            foreach ($rulesarr as $key => $rule){
                if ($rule['message']===null){
                    $a=new object();
                    $a->format=$rule['format'];
                    $str=get_string('err_'.$rule['type'], 'form', $a);
                    if (strpos($str, '[[')!==0){
                        $this->_rules[$field][$key]['message']=$str;
                    }
                }
            }
        }
    }

    function getLockOptionEndScript(){
        $js = '<script type="text/javascript" language="javascript">'."\n";
        $js .= "var ".$this->getAttribute('id')."items= {";
        foreach ($this->_dependencies as $dependentOn => $elements){
            $js .= "'$dependentOn'".' : {dependents :[';
            foreach ($elements as $element){
                $elementNames = $this->_getElNamesRecursive($element['dependent']);
                foreach ($elementNames as $dependent){
                    if ($dependent !=  $dependentOn) {
                        $js.="'".$dependent."', ";
                    }
                }
            }
            $js=rtrim($js, ', ');
            $js .= "],\n";
            $js .= "condition : '{$element['condition']}',\n";
            $js .= "value : '{$element['value']}'},\n";

        };
        $js=rtrim($js, ",\n");
        $js .= '};'."\n";
        $js .="lockoptionsallsetup('".$this->getAttribute('id')."');\n";
        $js .='</script>'."\n";
        return $js;
    }

    function _getElNamesRecursive(&$element, $group=null){
        if ($group==null){
            $el = $this->getElement($element);
        } else {
            $el = &$element;
        }
        if (is_a($el, 'HTML_QuickForm_group')){
            $group = $el;
            $elsInGroup = $group->getElements();
            $elNames = array();
            foreach ($elsInGroup as $elInGroup){
                $elNames = array_merge($elNames, $this->_getElNamesRecursive($elInGroup, $group));
            }
        }else{
            if ($group != null){
                $elNames = array($group->getElementName($el->getName()));
            } elseif (is_a($el, 'HTML_QuickForm_header')) {
                return null;
            } elseif (method_exists($el, 'getPrivateName')) {
                return array($el->getPrivateName());
            } else {
                $elNames = array($el->getName());
            }
        }
        return $elNames;

    }
    /**
     * Adds a dependency for $elementName which will be disabled if $condition is met.
     * If $condition = 'notchecked' (default) then the condition is that the $dependentOn element
     * is not checked. If $condition = 'checked' then the condition is that the $dependentOn element
     * is checked. If $condition is something else then it is checked to see if the value
     * of the $dependentOn element is equal to $condition.
     *
     * @param string $elementName the name of the element which will be disabled
     * @param string $dependentOn the name of the element whose state will be checked for
     *                            condition
     * @param string $condition the condition to check
     * @param mixed $value used in conjunction with condition.
     */
    function disabledIf($elementName, $dependentOn, $condition = 'notchecked', $value=null){
        $this->_dependencies[$dependentOn][] = array('dependent'=>$elementName,
                                    'condition'=>$condition, 'value'=>$value);
    }
    function _registerNoSubmitButton($addfieldsname){
        $this->_noSubmitButtons[]=$addfieldsname;
    }
    function _registerCancelButton($addfieldsname){
        $this->_cancelButtons[]=$addfieldsname;
    }
}


/**
 * A renderer for MoodleQuickForm that only uses XHTML and CSS and no
 * table tags, extends PEAR class HTML_QuickForm_Renderer_Tableless
 *
 * Stylesheet is part of standard theme and should be automatically included.
 *
 * @author      Jamie Pratt <me@jamiep.org>
 * @license    gpl license
 */
class MoodleQuickForm_Renderer extends HTML_QuickForm_Renderer_Tableless{

    /**
    * Element template array
    * @var      array
    * @access   private
    */
    var $_elementTemplates;
    /**
    * Template used when opening a hidden fieldset
    * (i.e. a fieldset that is opened when there is no header element)
    * @var      string
    * @access   private
    */
    var $_openHiddenFieldsetTemplate = "\n\t<fieldset class=\"hidden\">";
   /**
    * Header Template string
    * @var      string
    * @access   private
    */
    var $_headerTemplate =
       "\n\t\t<legend>{header}{advancedimg}{button}</legend>\n\t\t";

   /**
    * Template used when closing a fieldset
    * @var      string
    * @access   private
    */
    var $_closeFieldsetTemplate = "\n\t\t</fieldset>";

   /**
    * Required Note template string
    * @var      string
    * @access   private
    */
    var $_requiredNoteTemplate =
        "\n\t\t<div class=\"fdescription\">{requiredNote}</div>";

    var $_advancedElements = array();

    /**
     * Whether to display advanced elements (on page load)
     *
     * @var integer 1 means show 0 means hide
     */
    var $_showAdvanced;

    function MoodleQuickForm_Renderer(){
        // switch next two lines for ol li containers for form items.
        //        $this->_elementTemplates=array('default'=>"\n\t\t<li class=\"fitem\"><label>{label}{help}<!-- BEGIN required -->{req}<!-- END required --></label><div class=\"qfelement<!-- BEGIN error --> error<!-- END error --> {type}\"><!-- BEGIN error --><span class=\"error\">{error}</span><br /><!-- END error -->{element}</div></li>");
        $this->_elementTemplates = array('default'=>"\n\t\t<div class=\"fitem {advanced}\"><span class=\"fitemtitle\"><label>{label}<!-- BEGIN required -->{req}<!-- END required -->{advancedimg}</label>{help}</span><div class=\"felement {type}<!-- BEGIN error --> error<!-- END error -->\"><!-- BEGIN error --><span class=\"error\" id=\"id_error_{name}\">{error}</span><br /><!-- END error -->{element}</div></div>",
        'fieldset'=>"\n\t\t<div class=\"fitem {advanced}\"><span class=\"fitemtitle\"><label>{label}<!-- BEGIN required -->{req}<!-- END required -->{advancedimg}</label>{help}</span><fieldset class=\"felement {type}<!-- BEGIN error --> error<!-- END error -->\"><!-- BEGIN error --><span class=\"error\" id=\"id_error_{name}\">{error}</span><br /><!-- END error -->{element}</fieldset></div>");

        parent::HTML_QuickForm_Renderer_Tableless();
    }

    function setAdvancedElements($elements){
        $this->_advancedElements = $elements;
    }

    /**
     * What to do when starting the form
     *
     * @param MoodleQuickForm $form
     */
    function startForm(&$form){
        $this->_reqHTML = $form->getReqHTML();
        $this->_elementTemplates = str_replace('{req}', $this->_reqHTML, $this->_elementTemplates);
        $this->_advancedHTML = $form->getAdvancedHTML();
        $this->_showAdvanced = $form->getShowAdvanced();
        parent::startForm($form);
    }

    function startGroup(&$group, $required, $error){
        if (method_exists($group, 'getElementTemplateType')){
            $html = $this->_elementTemplates[$group->getElementTemplateType()];
        }else{
            $html = $this->_elementTemplates['default'];

        }
        if ($this->_showAdvanced){
            $advclass = ' advanced';
        } else {
            $advclass = ' advanced hide';
        }
        if (isset($this->_advancedElements[$group->getName()])){
            $html =str_replace(' {advanced}', $advclass, $html);
            $html =str_replace('{advancedimg}', $this->_advancedHTML, $html);
        } else {
            $html =str_replace(' {advanced}', '', $html);
            $html =str_replace('{advancedimg}', '', $html);
        }
        if (method_exists($group, 'getHelpButton')){
            $html =str_replace('{help}', $group->getHelpButton(), $html);
        }else{
            $html =str_replace('{help}', '', $html);
        }
        $html =str_replace('{name}', $group->getName(), $html);
        $html =str_replace('{type}', 'fgroup', $html);

        $this->_templates[$group->getName()]=$html;
        // Fix for bug in tableless quickforms that didn't allow you to stop a
        // fieldset before a group of elements.
        // if the element name indicates the end of a fieldset, close the fieldset
        if (   in_array($group->getName(), $this->_stopFieldsetElements)
            && $this->_fieldsetsOpen > 0
           ) {
            $this->_html .= $this->_closeFieldsetTemplate;
            $this->_fieldsetsOpen--;
        }
        parent::startGroup($group, $required, $error);
    }

    function renderElement(&$element, $required, $error){
        if (method_exists($element, 'getElementTemplateType')){
            $html = $this->_elementTemplates[$element->getElementTemplateType()];
        }else{
            $html = $this->_elementTemplates['default'];
        }
        if ($this->_showAdvanced){
            $advclass = ' advanced';
        } else {
            $advclass = ' advanced hide';
        }
        if (isset($this->_advancedElements[$element->getName()])){
            $html =str_replace(' {advanced}', $advclass, $html);
        } else {
            $html =str_replace(' {advanced}', '', $html);
        }
        if (isset($this->_advancedElements[$element->getName()])||$element->getName() == 'mform_showadvanced'){
            $html =str_replace('{advancedimg}', $this->_advancedHTML, $html);
        } else {
            $html =str_replace('{advancedimg}', '', $html);
        }
        $html =str_replace('{type}', 'f'.$element->getType(), $html);
        $html =str_replace('{name}', $element->getName(), $html);
        if (method_exists($element, 'getHelpButton')){
            $html = str_replace('{help}', $element->getHelpButton(), $html);
        }else{
            $html = str_replace('{help}', '', $html);

        }
        $this->_templates[$element->getName()] = $html;
        if (!is_null($element->getAttribute('id'))) {
            $id = $element->getAttribute('id');
        } else {
            $id = $element->getName();
        }
        $id = preg_replace('/^qf_/', '', $id, 1);
        if (strpos($id, 'id_') !== 0){
            $element->updateAttributes(array('id'=>'id_'.$id));
        }
        parent::renderElement($element, $required, $error);
    }

    function finishForm(&$form){
        parent::finishForm($form);
        // add a lockoptions script
        if ('' != ($script = $form->getLockOptionEndScript())) {
            $this->_html = $this->_html . "\n" . $script;
        }
    }
   /**
    * Called when visiting a header element
    *
    * @param    object     An HTML_QuickForm_header element being visited
    * @access   public
    * @return   void
    */
    function renderHeader(&$header)    {
        $name = $header->getName();

        $id = empty($name) ? '' : ' id="' . $name . '"';
        if (is_null($header->_text)) {
            $header_html = '';
        } elseif (!empty($name) && isset($this->_templates[$name])) {
            $header_html = str_replace('{header}', $header->toHtml(), $this->_templates[$name]);
        } else {
            $header_html = str_replace('{header}', $header->toHtml(), $this->_headerTemplate);
        }

        if (isset($this->_advancedElements[$name])){
            $header_html =str_replace('{advancedimg}', $this->_advancedHTML, $header_html);
        } else {
            $header_html =str_replace('{advancedimg}', '', $header_html);
        }
        $elementName='mform_showadvanced';
        if ($this->_showAdvanced==0){
            $buttonlabel = get_string('showadvanced', 'form');
        } else {
            $buttonlabel = get_string('hideadvanced', 'form');
        }

        if (isset($this->_advancedElements[$name])){
            $showtext="'".get_string('showadvanced', 'form')."'";
            $hidetext="'".get_string('hideadvanced', 'form')."'";
            //onclick returns false so if js is on then page is not submitted.
            $onclick = 'return showAdvancedOnClick(this, '.$hidetext.', '.$showtext.');';
            $button = '<input name="'.$elementName.'" value="'.$buttonlabel.'" type="submit" onclick="'.$onclick.'" />';
            $header_html =str_replace('{button}', $button, $header_html);
        } else {
            $header_html =str_replace('{button}', '', $header_html);
        }

        if ($this->_fieldsetsOpen > 0) {
            $this->_html .= $this->_closeFieldsetTemplate;
            $this->_fieldsetsOpen--;
        }

        $openFieldsetTemplate = str_replace('{id}', $id, $this->_openFieldsetTemplate);
        if ($this->_showAdvanced){
            $advclass = ' class="advanced"';
        } else {
            $advclass = ' class="advanced hide"';
        }
        if (isset($this->_advancedElements[$name])){
            $openFieldsetTemplate = str_replace('{advancedclass}', $advclass, $openFieldsetTemplate);
        } else {
            $openFieldsetTemplate = str_replace('{advancedclass}', '', $openFieldsetTemplate);
        }
        $this->_html .= $openFieldsetTemplate . $header_html;
        $this->_fieldsetsOpen++;
    } // end func renderHeader

    function getStopFieldsetElements(){
        return $this->_stopFieldsetElements;
    }
}


$GLOBALS['_HTML_QuickForm_default_renderer'] =& new MoodleQuickForm_Renderer();

MoodleQuickForm::registerElementType('checkbox', "$CFG->libdir/form/checkbox.php", 'MoodleQuickForm_checkbox');
MoodleQuickForm::registerElementType('file', "$CFG->libdir/form/file.php", 'MoodleQuickForm_file');
MoodleQuickForm::registerElementType('group', "$CFG->libdir/form/group.php", 'MoodleQuickForm_group');
MoodleQuickForm::registerElementType('password', "$CFG->libdir/form/password.php", 'MoodleQuickForm_password');
MoodleQuickForm::registerElementType('radio', "$CFG->libdir/form/radio.php", 'MoodleQuickForm_radio');
MoodleQuickForm::registerElementType('select', "$CFG->libdir/form/select.php", 'MoodleQuickForm_select');
MoodleQuickForm::registerElementType('text', "$CFG->libdir/form/text.php", 'MoodleQuickForm_text');
MoodleQuickForm::registerElementType('textarea', "$CFG->libdir/form/textarea.php", 'MoodleQuickForm_textarea');
MoodleQuickForm::registerElementType('date_selector', "$CFG->libdir/form/dateselector.php", 'MoodleQuickForm_date_selector');
MoodleQuickForm::registerElementType('date_time_selector', "$CFG->libdir/form/datetimeselector.php", 'MoodleQuickForm_date_time_selector');
MoodleQuickForm::registerElementType('htmleditor', "$CFG->libdir/form/htmleditor.php", 'MoodleQuickForm_htmleditor');
MoodleQuickForm::registerElementType('format', "$CFG->libdir/form/format.php", 'MoodleQuickForm_format');
MoodleQuickForm::registerElementType('static', "$CFG->libdir/form/static.php", 'MoodleQuickForm_static');
MoodleQuickForm::registerElementType('hidden', "$CFG->libdir/form/hidden.php", 'MoodleQuickForm_hidden');
MoodleQuickForm::registerElementType('modvisible', "$CFG->libdir/form/modvisible.php", 'MoodleQuickForm_modvisible');
MoodleQuickForm::registerElementType('modgroupmode', "$CFG->libdir/form/modgroupmode.php", 'MoodleQuickForm_modgroupmode');
MoodleQuickForm::registerElementType('selectyesno', "$CFG->libdir/form/selectyesno.php", 'MoodleQuickForm_selectyesno');
MoodleQuickForm::registerElementType('modgrade', "$CFG->libdir/form/modgrade.php", 'MoodleQuickForm_modgrade');
MoodleQuickForm::registerElementType('cancel', "$CFG->libdir/form/cancel.php", 'MoodleQuickForm_cancel');
MoodleQuickForm::registerElementType('button', "$CFG->libdir/form/button.php", 'MoodleQuickForm_button');
MoodleQuickForm::registerElementType('choosecoursefile', "$CFG->libdir/form/choosecoursefile.php", 'MoodleQuickForm_choosecoursefile');
//MoodleQuickForm::registerElementType('header', "$CFG->libdir/form/header.php", 'MoodleQuickForm_header');  // where is it?

?>