quizdata.php

<?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 dynamically sends quiz data to clients
 *
 * @copyright Davo Smith <moodle@davosmith.co.uk>
 * @package mod_realtimequiz
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 **/

define('AJAX_SCRIPT', true);

require_once('../../config.php');
global $CFG, $DB, $USER, $PAGE;
require_once($CFG->dirroot.'/mod/realtimequiz/lib.php');
require_once($CFG->dirroot.'/mod/realtimequiz/locallib.php');
require_once($CFG->libdir.'/filelib.php');

require_login();
require_sesskey();
$requesttype = required_param('requesttype', PARAM_ALPHA);
$quizid = required_param('quizid', PARAM_INT);

/***********************************************************
 * End of functions - start of main code
 ***********************************************************/

realtimequiz_start_response();

if (!$realtimequiz = $DB->get_record("realtimequiz", ['id' => $quizid])) {
    realtimequiz_send_error("Quiz ID incorrect");
    realtimequiz_end_response();
    die();
}
if (!$course = $DB->get_record("course", ['id' => $realtimequiz->course])) {
    realtimequiz_send_error("Course is misconfigured");
    realtimequiz_end_response();
    die();
}
if (!$cm = get_coursemodule_from_instance("realtimequiz", $realtimequiz->id, $course->id)) {
    realtimequiz_send_error("Course Module ID was incorrect");
    realtimequiz_end_response();
    die();
}
if ($CFG->version < 2011120100) {
    $context = get_context_instance(CONTEXT_MODULE, $cm->id);
} else {
    $context = context_module::instance($cm->id);
}
$PAGE->set_context($context);

if (!has_capability('mod/realtimequiz:attempt', $context)) {
    realtimequiz_send_error(get_string('notallowedattempt', 'realtimequiz'));
    realtimequiz_end_response();
    die();
}

$status = $realtimequiz->status;
if ($status === false) {
    realtimequiz_send_error(get_string('badquizid', 'realtimequiz').$quizid);
} else {
    $status = realtimequiz_update_status($quizid,
                                         $status); // Check if the current status should change due to a timeout.

    if ($requesttype == 'quizrunning') {
        if (($status == REALTIMEQUIZ_STATUS_NOTRUNNING) || ($status == REALTIMEQUIZ_STATUS_FINALRESULTS)) {
            // Not running / finished.
            realtimequiz_send_not_running();
        } else {
            realtimequiz_send_running();
        }
    } else if ($requesttype == 'startquiz') {
        if (has_capability('mod/realtimequiz:control', $context)) {
            $session = new stdClass();
            $session->timestamp = time();
            $session->name = optional_param('sessionname', '', PARAM_TEXT);
            $session->quizid = $quizid;
            $session->id = $DB->insert_record('realtimequiz_session', $session);

            $quiz = $DB->get_record('realtimequiz', ['id' => $quizid]);
            $quiz->currentsessionid = $session->id;
            $quiz->status = REALTIMEQUIZ_STATUS_READYTOSTART;
            $quiz->currentquestion = 0;
            $quiz->classresult = 0;
            $quiz->questionresult = 0;
            $DB->update_record('realtimequiz', $quiz);

            realtimequiz_send_running();
        } else {
            realtimequiz_send_error(get_string('notauthorised', 'realtimequiz'));
        }

    } else {

        switch ($status) {

            case REALTIMEQUIZ_STATUS_NOTRUNNING:   // Quiz is not running.
                realtimequiz_send_not_running(); // We don't care what they asked for.
                break;

            case REALTIMEQUIZ_STATUS_READYTOSTART: // Quiz is ready to start.
                if ($requesttype == 'nextquestion') {
                    realtimequiz_goto_question($context, $quizid, 1);
                } else {
                    realtimequiz_send_await_question(); // Don't care what they asked for.
                    realtimequiz_number_students($quizid);
                }
                break;

            case REALTIMEQUIZ_STATUS_PREVIEWQUESTION: // Previewing question (send it out, but ask them to wait before showing).
                realtimequiz_send_question($quizid, $context, true); // We don't care what they asked for.
                break;

            case REALTIMEQUIZ_STATUS_SHOWQUESTION: // Question being displayed.
                if ($requesttype == 'getquestion' || $requesttype == 'nextquestion' || $requesttype == 'teacherrejoin') {
                    // Student asked for a question - so send it.
                    realtimequiz_send_question($quizid, $context);

                } else if ($requesttype == 'postanswer') {
                    $questionnum = required_param('question', PARAM_INT);
                    $userid = $USER->id;
                    $answerid = required_param('answer', PARAM_INT);
                    realtimequiz_record_answer($quizid, $questionnum, $userid, $answerid, $context);

                } else if ($requesttype == 'getresults') {
                    $questionnum = required_param('question', PARAM_INT);
                    if (realtimequiz_current_question($quizid, $questionnum)) {
                        $timeleft = $DB->get_field('realtimequiz', 'nextendtime', ['id' => $quizid]) - time();
                        if ($timeleft < 0) {
                            $timeleft = 0;
                        }
                        realtimequiz_send_await_results($timeleft); // Results not yet ready.
                    } else {
                        realtimequiz_send_question($quizid, $context); // Asked for results for wrong question.
                    }

                } else {
                    realtimequiz_send_error(get_string('unknownrequest', 'realtimequiz').$requesttype.'\'');
                }
                break;

            case REALTIMEQUIZ_STATUS_SHOWRESULTS: // Results being displayed.
                if ($requesttype == 'getquestion') { // Asking for the next question.
                    realtimequiz_send_await_question();

                } else if ($requesttype == 'postanswer' || $requesttype == 'getresults' || $requesttype == 'teacherrejoin') {
                    realtimequiz_send_results($quizid);

                } else if ($requesttype == 'nextquestion') {
                    $clientquestionnum = required_param('currentquestion', PARAM_INT);
                    $questionid = $DB->get_field('realtimequiz', 'currentquestion', ['id' => $quizid]);
                    $questionnum = $DB->get_field('realtimequiz_question', 'questionnum', ['id' => $questionid]);
                    if ($clientquestionnum != $questionnum) {
                        realtimequiz_send_results($quizid);
                    } else {
                        $questionnum++;
                        realtimequiz_goto_question($context, $quizid, $questionnum);
                    }

                } else {
                    realtimequiz_send_error(get_string('unknownrequest', 'realtimequiz').$requesttype.'\'');
                }
                break;

            case REALTIMEQUIZ_STATUS_FINALRESULTS: // Showing the final totals, etc.
                realtimequiz_send_final_results($quizid);
                break;

            default:
                realtimequiz_send_error(get_string('incorrectstatus', 'realtimequiz').$status.'\'');
                break;
        }
    }
}

realtimequiz_end_response();