Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * This file defines a class with "Number of errors" grading strategy logic

 *

 * @package    workshopform_numerrors

 * @copyright  2009 David Mudrak <david.mudrak@gmail.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

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

require_once(__DIR__ . '/../lib.php');        // Interface definition.

require_once($CFG->libdir . '/gradelib.php'); // To handle float vs decimal issues.

/**

 * Server workshop files

 *

 * @category files

 * @param stdClass $course course object

 * @param stdClass $cm course module object

 * @param stdClass $context context object

 * @param string $filearea file area

 * @param array $args extra arguments

 * @param bool $forcedownload whether or not force download

 * @param array $options additional options affecting the file serving

 * @return bool

 */

function workshopform_numerrors_pluginfile($course, $cm, $context, $filearea, array $args, $forcedownload, array $options=array()) {

    global $DB;

    if ($context->contextlevel != CONTEXT_MODULE) {

        return false;

    }

    require_login($course, true, $cm);

    if ($filearea !== 'description') {

        return false;

    }

    $itemid = (int)array_shift($args); // the id of the assessment form dimension

    if (!$workshop = $DB->get_record('workshop', array('id' => $cm->instance))) {

        send_file_not_found();

    }

    if (!$dimension = $DB->get_record('workshopform_numerrors', array('id' => $itemid ,'workshopid' => $workshop->id))) {

        send_file_not_found();

    }

    // TODO now make sure the user is allowed to see the file

    // (media embedded into the dimension description)

    $fs = get_file_storage();

    $relativepath = implode('/', $args);

    $fullpath = "/$context->id/workshopform_numerrors/$filearea/$itemid/$relativepath";

    if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {

        return false;

    }

    // finally send the file

    send_stored_file($file, 0, 0, $forcedownload, $options);

}

/**

 * "Number of errors" grading strategy logic.

 */

class workshop_numerrors_strategy implements workshop_strategy {

    /** @var default number of dimensions to show */

    const MINDIMS = 3;

    /** @var number of dimensions to add */

    const ADDDIMS = 2;

    /** @var workshop the parent workshop instance */

    protected $workshop;

    /** @var array definition of the assessment form fields */

    protected $dimensions = null;

    /** @var array mapping of the number of errors to a grade */

    protected $mappings = null;

    /** @var array options for dimension description fields */

    protected $descriptionopts;

    /**

     * Constructor

     *

     * @param workshop $workshop The workshop instance record

     * @return void

     */

    public function __construct(workshop $workshop) {

        $this->workshop         = $workshop;

        $this->dimensions       = $this->load_fields();

        $this->mappings         = $this->load_mappings();

        $this->descriptionopts  = array('trusttext' => true, 'subdirs' => false, 'maxfiles' => -1);

    }

    /**

     * Factory method returning an instance of an assessment form editor class

     *

     * @param $actionurl URL of form handler, defaults to auto detect the current url

     */

    public function get_edit_strategy_form($actionurl=null) {

        global $CFG;    // needed because the included files use it

        global $PAGE;

        require_once(__DIR__ . '/edit_form.php');

        $fields             = $this->prepare_form_fields($this->dimensions, $this->mappings);

        $nodimensions       = count($this->dimensions);

        $norepeatsdefault   = max($nodimensions + self::ADDDIMS, self::MINDIMS);

        $norepeats          = optional_param('norepeats', $norepeatsdefault, PARAM_INT);    // number of dimensions

        $noadddims          = optional_param('noadddims', '', PARAM_ALPHA);                 // shall we add more?

        if ($noadddims) {

            $norepeats += self::ADDDIMS;

        }

        // Append editor context to editor options, giving preference to existing context.

        $this->descriptionopts = array_merge(array('context' => $PAGE->context), $this->descriptionopts);

        // prepare the embeded files

        for ($i = 0; $i < $nodimensions; $i++) {

            // prepare all editor elements

            $fields = file_prepare_standard_editor($fields, 'description__idx_'.$i, $this->descriptionopts,

                $PAGE->context, 'workshopform_numerrors', 'description', $fields->{'dimensionid__idx_'.$i});

        }

        $customdata = array();

        $customdata['workshop'] = $this->workshop;

        $customdata['strategy'] = $this;

        $customdata['norepeats'] = $norepeats;

        $customdata['nodimensions'] = $nodimensions;

        $customdata['descriptionopts'] = $this->descriptionopts;

        $customdata['current']  = $fields;

        $attributes = array('class' => 'editstrategyform');

        return new workshop_edit_numerrors_strategy_form($actionurl, $customdata, 'post', '', $attributes);

    }

    /**

     * Save the assessment dimensions into database

     *

     * Saves data into the main strategy form table. If the record->id is null or zero,

     * new record is created. If the record->id is not empty, the existing record is updated. Records with

     * empty 'description' field are removed from database.

     * The passed data object are the raw data returned by the get_data().

     *

     * @uses $DB

     * @param stdClass $data Raw data returned by the dimension editor form

     * @return void

     */

    public function save_edit_strategy_form(stdclass $data) {

        global $DB, $PAGE;

        $workshopid = $data->workshopid;

        $norepeats  = $data->norepeats;

        $data       = $this->prepare_database_fields($data);

        $records    = $data->numerrors; // data to be saved into {workshopform_numerrors}

        $mappings   = $data->mappings;  // data to be saved into {workshopform_numerrors_map}

        $todelete   = array();          // dimension ids to be deleted

        $maxnonegative = 0;             // maximum number of (weighted) negative responses

        for ($i=0; $i < $norepeats; $i++) {

            $record = $records[$i];

            if (0 == strlen(trim($record->description_editor['text']))) {

                if (!empty($record->id)) {

                    // existing dimension record with empty description - to be deleted

                    $todelete[] = $record->id;

                }

                continue;

            }

            if (empty($record->id)) {

                // new field

                $record->id = $DB->insert_record('workshopform_numerrors', $record);

            } else {

                // exiting field

                $DB->update_record('workshopform_numerrors', $record);

            }

            $maxnonegative += $record->weight;

            // re-save with correct path to embeded media files

            $record = file_postupdate_standard_editor($record, 'description', $this->descriptionopts, $PAGE->context,

                                                      'workshopform_numerrors', 'description', $record->id);

            $DB->update_record('workshopform_numerrors', $record);

        }

        $this->delete_dimensions($todelete);

        // re-save the mappings

        $todelete = array();

        foreach ($data->mappings as $nonegative => $grade) {

            if (is_null($grade)) {

                // no grade set for this number of negative responses

                $todelete[] = $nonegative;

                continue;

            }

            if (isset($this->mappings[$nonegative])) {

                $DB->set_field('workshopform_numerrors_map', 'grade', $grade,

                            array('workshopid' => $this->workshop->id, 'nonegative' => $nonegative));

            } else {

                $DB->insert_record('workshopform_numerrors_map',

                            (object)array('workshopid' => $this->workshop->id, 'nonegative' => $nonegative, 'grade' => $grade));

            }

        }

        // clear mappings that are not valid any more

        if (!empty($todelete)) {

            list($insql, $params) = $DB->get_in_or_equal($todelete, SQL_PARAMS_NAMED);

            $insql = "nonegative $insql OR ";

        } else {

            $insql = '';

        }

        $sql = "DELETE FROM {workshopform_numerrors_map}

                      WHERE (($insql nonegative > :maxnonegative) AND (workshopid = :workshopid))";

        $params['maxnonegative'] = $maxnonegative;

        $params['workshopid']   = $this->workshop->id;

        $DB->execute($sql, $params);

    }

    /**

     * Factory method returning an instance of an assessment form

     *

     * @param moodle_url $actionurl URL of form handler, defaults to auto detect the current url

     * @param string $mode          Mode to open the form in: preview/assessment

     * @param stdClass $assessment

     * @param bool $editable

     * @param array $options

     */

    public function get_assessment_form(moodle_url $actionurl=null, $mode='preview', stdclass $assessment=null, $editable=true, $options=array()) {

        global $CFG;    // needed because the included files use it

        global $PAGE;

        global $DB;

        require_once(__DIR__ . '/assessment_form.php');

        $fields         = $this->prepare_form_fields($this->dimensions, $this->mappings);

        $nodimensions   = count($this->dimensions);

        // rewrite URLs to the embeded files

        for ($i = 0; $i < $nodimensions; $i++) {

            $fields->{'description__idx_'.$i} = file_rewrite_pluginfile_urls($fields->{'description__idx_'.$i},

                'pluginfile.php', $PAGE->context->id, 'workshopform_numerrors', 'description', $fields->{'dimensionid__idx_'.$i});

        }

        if ('assessment' === $mode and !empty($assessment)) {

            // load the previously saved assessment data

            $grades = $this->get_current_assessment_data($assessment);

            $current = new stdclass();

            for ($i = 0; $i < $nodimensions; $i++) {

                $dimid = $fields->{'dimensionid__idx_'.$i};

                if (isset($grades[$dimid])) {

                    $current->{'gradeid__idx_'.$i}      = $grades[$dimid]->id;

                    $current->{'grade__idx_'.$i}        = ($grades[$dimid]->grade == 0 ? -1 : 1);

                    $current->{'peercomment__idx_'.$i}  = $grades[$dimid]->peercomment;

                }

            }

        }

        // set up the required custom data common for all strategies

        $customdata['workshop'] = $this->workshop;

        $customdata['strategy'] = $this;

        $customdata['mode']     = $mode;

        $customdata['options']  = $options;

        // set up strategy-specific custom data

        $customdata['nodims']   = $nodimensions;

        $customdata['fields']   = $fields;

        $customdata['current']  = isset($current) ? $current : null;

        $attributes = array('class' => 'assessmentform numerrors');

        return new workshop_numerrors_assessment_form($actionurl, $customdata, 'post', '', $attributes, $editable);

    }

    /**

     * Saves the filled assessment

     *

     * This method processes data submitted using the form returned by {@link get_assessment_form()}

     *

     * @param stdClass $assessment Assessment being filled

     * @param stdClass $data       Raw data as returned by the assessment form

     * @return float|null          Raw grade (from 0.00000 to 100.00000) for submission as suggested by the peer

     */

    public function save_assessment(stdclass $assessment, stdclass $data) {

        global $DB;

        if (!isset($data->nodims)) {

            throw new coding_exception('You did not send me the number of assessment dimensions to process');

        }

        for ($i = 0; $i < $data->nodims; $i++) {

            $grade = new stdclass();

            $grade->id                  = $data->{'gradeid__idx_' . $i};

            $grade->assessmentid        = $assessment->id;

            $grade->strategy            = 'numerrors';

            $grade->dimensionid         = $data->{'dimensionid__idx_' . $i};

            $grade->grade               = ($data->{'grade__idx_' . $i} <= 0 ? 0 : 1);

            $grade->peercomment         = $data->{'peercomment__idx_' . $i};

            $grade->peercommentformat   = FORMAT_HTML;

            if (empty($grade->id)) {

                // new grade

                $grade->id = $DB->insert_record('workshop_grades', $grade);

            } else {

                // updated grade

                $DB->update_record('workshop_grades', $grade);

            }

        }

        return $this->update_peer_grade($assessment);

    }

    /**

     * Has the assessment form been defined and is ready to be used by the reviewers?

     *

     * @return boolean

     */

    public function form_ready() {

        if (count($this->dimensions) > 0) {

            return true;

        }

        return false;

    }

    /**

     * @see parent::get_assessments_recordset()

     */

    public function get_assessments_recordset($restrict=null) {

       global $DB;

        $sql = 'SELECT s.id AS submissionid,

                       a.id AS assessmentid, a.weight AS assessmentweight, a.reviewerid, a.gradinggrade,

                       g.dimensionid, g.grade

                  FROM {workshop_submissions} s

                  JOIN {workshop_assessments} a ON (a.submissionid = s.id)

                  JOIN {workshop_grades} g ON (g.assessmentid = a.id AND g.strategy = :strategy)

                 WHERE s.example=0 AND s.workshopid=:workshopid'; // to be cont.

        $params = array('workshopid' => $this->workshop->id, 'strategy' => $this->workshop->strategy);

        if (is_null($restrict)) {

            // update all users - no more conditions

        } elseif (!empty($restrict)) {

            list($usql, $uparams) = $DB->get_in_or_equal($restrict, SQL_PARAMS_NAMED);

            $sql .= " AND a.reviewerid $usql";

            $params = array_merge($params, $uparams);

        } else {

            throw new coding_exception('Empty value is not a valid parameter here');

        }

        $sql .= ' ORDER BY s.id'; // this is important for bulk processing

        return $DB->get_recordset_sql($sql, $params);

    }

    /**

     * @see parent::get_dimensions_info()

     */

    public function get_dimensions_info() {

        global $DB;

        $params = array('workshopid' => $this->workshop->id);

        $dimrecords = $DB->get_records('workshopform_numerrors', array('workshopid' => $this->workshop->id), 'sort', 'id,weight');

        foreach ($dimrecords as $dimid => $dimrecord) {

            $dimrecords[$dimid]->min = 0;

            $dimrecords[$dimid]->max = 1;

        }

        return $dimrecords;

    }

    /**

     * Is a given scale used by the instance of workshop?

     *

     * This grading strategy does not use scales.

     *

     * @param int $scaleid id of the scale to check

     * @param int|null $workshopid id of workshop instance to check, checks all in case of null

     * @return bool

     */

    public static function scale_used($scaleid, $workshopid=null) {

        return false;

    }

    /**

     * Delete all data related to a given workshop module instance

     *

     * @see workshop_delete_instance()

     * @param int $workshopid id of the workshop module instance being deleted

     * @return void

     */

    public static function delete_instance($workshopid) {

        global $DB;

        $DB->delete_records('workshopform_numerrors', array('workshopid' => $workshopid));

        $DB->delete_records('workshopform_numerrors_map', array('workshopid' => $workshopid));

    }

    ////////////////////////////////////////////////////////////////////////////////

    // Internal methods                                                           //

    ////////////////////////////////////////////////////////////////////////////////

    /**

     * Loads the fields of the assessment form currently used in this workshop

     *

     * @return array definition of assessment dimensions

     */

    protected function load_fields() {

        global $DB;

        $sql = 'SELECT *

                  FROM {workshopform_numerrors}

                 WHERE workshopid = :workshopid

                 ORDER BY sort';

        $params = array('workshopid' => $this->workshop->id);

        return $DB->get_records_sql($sql, $params);

    }

    /**

     * Loads the mappings of the number of errors to the grade

     *

     * @return array of records

     */

    protected function load_mappings() {

        global $DB;

        return $DB->get_records('workshopform_numerrors_map', array('workshopid' => $this->workshop->id), 'nonegative',

                                'nonegative,grade'); // we can use nonegative as key here as it must be unique within workshop

    }

    /**

     * Prepares the database data to be used by the mform

     *

     * @param array $dims Array of raw dimension records as returned by {@link load_fields()}

     * @param array $maps Array of raw mapping records as returned by {@link load_mappings()}

     * @return array Array of fields data to be used by the mform set_data

     */

    protected function prepare_form_fields(array $dims, array $maps) {

        $formdata = new stdclass();

        $key = 0;

        foreach ($dims as $dimension) {

            $formdata->{'dimensionid__idx_' . $key}             = $dimension->id;

            $formdata->{'description__idx_' . $key}             = $dimension->description;

            $formdata->{'description__idx_' . $key.'format'}    = $dimension->descriptionformat;

            $formdata->{'grade0__idx_' . $key}                  = $dimension->grade0;

            $formdata->{'grade1__idx_' . $key}                  = $dimension->grade1;

            $formdata->{'weight__idx_' . $key}                  = $dimension->weight;

            $key++;

        }

        foreach ($maps as $nonegative => $map) {

            $formdata->{'map__idx_' . $nonegative} = $map->grade;

        }

        return $formdata;

    }

    /**

     * Deletes dimensions and removes embedded media from its descriptions

     *

     * todo we may check that there are no assessments done using these dimensions and probably remove them

     *

     * @param array $ids list to delete

     * @return void

     */

    protected function delete_dimensions(array $ids) {

        global $DB, $PAGE;

        $fs         = get_file_storage();

        foreach ($ids as $id) {

            $fs->delete_area_files($PAGE->context->id, 'workshopform_numerrors', 'description', $id);

        }

        $DB->delete_records_list('workshopform_numerrors', 'id', $ids);

    }

    /**

     * Prepares data returned by {@link workshop_edit_numerrors_strategy_form} so they can be saved into database

     *

     * It automatically adds some columns into every record. The sorting is

     * done by the order of the returned array and starts with 1.

     * Called internally from {@link save_edit_strategy_form()} only. Could be private but

     * keeping protected for unit testing purposes.

     *

     * @param stdClass $raw Raw data returned by mform

     * @return array Array of objects to be inserted/updated in DB

     */

    protected function prepare_database_fields(stdclass $raw) {

        global $PAGE;

        $cook               = new stdclass();   // to be returned

        $cook->numerrors    = array();          // to be stored in {workshopform_numerrors}

        $cook->mappings     = array();          // to be stored in {workshopform_numerrors_map}

        for ($i = 0; $i < $raw->norepeats; $i++) {

            $cook->numerrors[$i]                        = new stdclass();

            $cook->numerrors[$i]->id                    = $raw->{'dimensionid__idx_'.$i};

            $cook->numerrors[$i]->workshopid            = $this->workshop->id;

            $cook->numerrors[$i]->sort                  = $i + 1;

            $cook->numerrors[$i]->description_editor    = $raw->{'description__idx_'.$i.'_editor'};

            $cook->numerrors[$i]->grade0                = $raw->{'grade0__idx_'.$i};

            $cook->numerrors[$i]->grade1                = $raw->{'grade1__idx_'.$i};

            $cook->numerrors[$i]->weight                = $raw->{'weight__idx_'.$i};

        }

        $i = 1;

        while (isset($raw->{'map__idx_'.$i})) {

            if (is_numeric($raw->{'map__idx_'.$i})) {

                $cook->mappings[$i] = $raw->{'map__idx_'.$i}; // should be a value from 0 to 100

            } else {

                $cook->mappings[$i] = null; // the user did not set anything

            }

            $i++;

        }

        return $cook;

    }

    /**

     * Returns the list of current grades filled by the reviewer

     *

     * @param stdClass $assessment Assessment record

     * @return array of filtered records from the table workshop_grades

     */

    protected function get_current_assessment_data(stdclass $assessment) {

        global $DB;

        if (empty($this->dimensions)) {

            return array();

        }

        list($dimsql, $dimparams) = $DB->get_in_or_equal(array_keys($this->dimensions), SQL_PARAMS_NAMED);

        // beware! the caller may rely on the returned array is indexed by dimensionid

        $sql = "SELECT dimensionid, wg.*

                  FROM {workshop_grades} wg

                 WHERE assessmentid = :assessmentid AND strategy= :strategy AND dimensionid $dimsql";

        $params = array('assessmentid' => $assessment->id, 'strategy' => 'numerrors');

        $params = array_merge($params, $dimparams);

        return $DB->get_records_sql($sql, $params);

    }

    /**

     * Aggregates the assessment form data and sets the grade for the submission given by the peer

     *

     * @param stdClass $assessment Assessment record

     * @return float|null          Raw grade (0.00000 to 100.00000) for submission as suggested by the peer

     */

    protected function update_peer_grade(stdclass $assessment) {

        $grades     = $this->get_current_assessment_data($assessment);

        $suggested  = $this->calculate_peer_grade($grades);

        if (!is_null($suggested)) {

            $this->workshop->set_peer_grade($assessment->id, $suggested);

        }

        return $suggested;

    }

    /**

     * Calculates the aggregated grade given by the reviewer

     *

     * @param array $grades Grade records as returned by {@link get_current_assessment_data}

     * @return float|null   Raw grade (0.00000 to 100.00000) for submission as suggested by the peer

     */

    protected function calculate_peer_grade(array $grades) {

        if (empty($grades)) {

            return null;

        }

        $sumerrors  = 0;    // sum of the weighted errors (i.e. the negative responses)

        foreach ($grades as $grade) {

            if (grade_floats_different($grade->grade, 1.00000)) {

                // negative reviewer's response

                $sumerrors += $this->dimensions[$grade->dimensionid]->weight;

            }

        }

        return $this->errors_to_grade($sumerrors);

    }

    /**

     * Returns a grade 0.00000 to 100.00000 for the given number of errors

     *

     * This is where we use the mapping table defined by the teacher. If a grade for the given

     * number of errors (negative assertions) is not defined, the most recently defined one is used.

     * Example of the defined mapping:

     * Number of errors | Grade

     *                0 | 100%  (always)

     *                1 | -     (not defined)

     *                2 | 80%

     *                3 | 60%

     *                4 | -

     *                5 | 30%

     *                6 | 0%

     * With this mapping, one error is mapped to 100% grade and 4 errors is mapped to 60%.

     *

     * @param mixed $numerrors Number of errors

     * @return float          Raw grade (0.00000 to 100.00000) for the given number of negative assertions

     */

    protected function errors_to_grade($numerrors) {

        $grade = 100.00000;

        for ($i = 1; $i <= $numerrors; $i++) {

            if (isset($this->mappings[$i])) {

                $grade = $this->mappings[$i]->grade;

            }

        }

        if ($grade > 100.00000) {

            $grade = 100.00000;

        }

        if ($grade < 0.00000) {

            $grade = 0.00000;

        }

        return grade_floatval($grade);

    }

}