Merge branch 'main' into issue-3911issue-3911

26 files changed, 375 insertions, 235 deletions

diff --git a/app/controllers/course/admission.php b/app/controllers/course/admission.php
index 56342bb..14a9b20 100644
--- a/app/controllers/course/admission.php
+++ b/app/controllers/course/admission.php
@@ -31,7 +31,7 @@ class Course_AdmissionController extends AuthenticatedController
         if (!get_object_type($this->course_id, ['sem']) ||
             SeminarCategories::GetBySeminarId($this->course_id)->studygroup_mode ||
             !$GLOBALS['perm']->have_studip_perm('tutor', $this->course_id)) {
-            throw new Trails_Exception(403);
+            throw new Trails\Exception(403);
         }
 
         $this->course = Course::find($this->course_id);
@@ -488,7 +488,7 @@ class Course_AdmissionController extends AuthenticatedController
             }
             $this->course_set_name = $course_set->getName();
         } else {
-            throw new Trails_Exception(400);
+            throw new Trails\Exception(400);
         }
     }
 
@@ -503,7 +503,7 @@ class Course_AdmissionController extends AuthenticatedController
                 $this->redirect($response->headers['Location']);
             }
         } else {
-            throw new Trails_Exception(403);
+            throw new Trails\Exception(403);
         }
     }
 
@@ -518,7 +518,7 @@ class Course_AdmissionController extends AuthenticatedController
                 $this->redirect($response->headers['Location']);
             }
         } else {
-            throw new Trails_Exception(403);
+            throw new Trails\Exception(403);
         }
     }
 
diff --git a/app/controllers/course/basicdata.php b/app/controllers/course/basicdata.php
index 8cc7d94..97ec053 100644
--- a/app/controllers/course/basicdata.php
+++ b/app/controllers/course/basicdata.php
@@ -445,6 +445,14 @@ class Course_BasicdataController extends AuthenticatedController
             $widget = new CourseManagementSelectWidget();
             $sidebar->addWidget($widget);
         }
+
+        foreach ($this->flash['msg'] ?? [] as $msg) {
+            match ($msg[0]) {
+                'msg'   => PageLayout::postSuccess($msg[1]),
+                'error' => PageLayout::postError($msg[1]),
+                'info'  => PageLayout::postInfo($msg[1]),
+            };
+        }
     }
 
     /**
@@ -956,20 +964,30 @@ class Course_BasicdataController extends AuthenticatedController
     private function _getTypes($sem, $data, &$changable = true)
     {
         $sem_types = [];
+
+        $sem_classes = [];
         if ($GLOBALS['perm']->have_perm("admin")) {
             foreach (SemClass::getClasses() as $sc) {
                 if (!$sc['course_creation_forbidden']) {
-                    $sem_types[$sc['name']] = array_map(function ($st) {
-                        return $st['name'];
-                    }, $sc->getSemTypes());
+                    $sem_classes[] = $sc;
                 }
             }
         } else {
-            $sc = $sem->getSemClass();
+            $sem_classes[] = $sem->getSemClass();
+        }
+
+        if (!$sem->isStudyGroup()) {
+            $sem_classes = array_filter($sem_classes, function (SemClass $sc) {
+                return !$sc['studygroup_mode'];
+            });
+        }
+
+        foreach ($sem_classes as $sc) {
             $sem_types[$sc['name']] = array_map(function ($st) {
                 return $st['name'];
             }, $sc->getSemTypes());
         }
+
         if (!in_array($data['status'], array_flatten(array_values(array_map('array_keys', $sem_types))))) {
             $class_name = $sem->getSemClass()->offsetGet('name');
             if (!isset($sem_types[$class_name])) {
diff --git a/app/controllers/course/block_appointments.php b/app/controllers/course/block_appointments.php
index fef0d31..ad28b1e 100644
--- a/app/controllers/course/block_appointments.php
+++ b/app/controllers/course/block_appointments.php
@@ -33,7 +33,7 @@ class Course_BlockAppointmentsController extends AuthenticatedController
             SeminarCategories::GetBySeminarId($this->course_id)->studygroup_mode ||
             !$GLOBALS['perm']->have_studip_perm("tutor", $this->course_id)
         ) {
-            throw new Trails_Exception(400);
+            throw new Trails\Exception(400);
         }
         PageLayout::setHelpKeyword('Basis.VeranstaltungenVerwaltenAendernVonZeitenUndTerminen');
         PageLayout::setTitle(Course::findCurrent()->getFullName() . " - " . _('Blockveranstaltungstermine anlegen'));
diff --git a/app/controllers/course/cancel_dates.php b/app/controllers/course/cancel_dates.php
index 0d5463c..8da0d09 100644
--- a/app/controllers/course/cancel_dates.php
+++ b/app/controllers/course/cancel_dates.php
@@ -39,7 +39,7 @@ class Course_CancelDatesController extends AuthenticatedController
             $this->course_id = $this->dates[0]->range_id;
         }
         if (!get_object_type($this->course_id, ['sem']) || !$perm->have_studip_perm("tutor", $this->course_id)) {
-            throw new Trails_Exception(400);
+            throw new Trails\Exception(400);
         }
         PageLayout::setHelpKeyword('Basis.VeranstaltungenVerwaltenAendernVonZeitenUndTerminen');
         PageLayout::setTitle(Course::findCurrent()->getFullName() . " - " . _('Veranstaltungstermine absagen'));
diff --git a/app/controllers/course/change_view.php b/app/controllers/course/change_view.php
index 156a68a..63395b6 100644
--- a/app/controllers/course/change_view.php
+++ b/app/controllers/course/change_view.php
@@ -16,7 +16,6 @@
  */
 class Course_ChangeViewController extends AuthenticatedController
 {
-    // see Trails_Controller#before_filter
     public function before_filter(&$action, &$args)
     {
         parent::before_filter($action, $args);
@@ -28,7 +27,7 @@ class Course_ChangeViewController extends AuthenticatedController
      * Sets the current course into participant view.
      * Only available for tutor upwards.
      *
-     * @throws Trails_Exception Someone with unfitting rights tried to call here.
+     * @throws Trails\Exception Someone with unfitting rights tried to call here.
      */
     public function set_changed_view_action()
     {
@@ -43,7 +42,7 @@ class Course_ChangeViewController extends AuthenticatedController
      * Resets a course currently in participant view to normal view
      * with real rights.
      *
-     * @throws Trails_Exception Someone with unfitting rights tried to call here.
+     * @throws Trails\Exception Someone with unfitting rights tried to call here.
      */
     public function reset_changed_view_action()
     {
diff --git a/app/controllers/course/contentmodules.php b/app/controllers/course/contentmodules.php
index 923c61b..d37d1bb 100644
--- a/app/controllers/course/contentmodules.php
+++ b/app/controllers/course/contentmodules.php
@@ -261,14 +261,19 @@ class Course_ContentmodulesController extends AuthenticatedController
             }
         }
 
-        PageLayout::setTitle(sprintf(_('Informationen über %s'), $this->metadata['displayname']));
+        $this->metadata['icon'] = $this->getIconFromMetadata($this->metadata, $this->plugin);
+
+        PageLayout::setTitle(sprintf(
+            _('Informationen über %s'),
+            $this->metadata['displayname'] ?? $this->plugin->getPluginName()
+        ));
     }
 
     private function getModules(Range $context)
     {
         $list = [];
 
-        foreach (PluginEngine::getPlugins('StudipModule') as $plugin) {
+        foreach (PluginEngine::getPlugins(StudipModule::class) as $plugin) {
             if (!$plugin->isActivatableForContext($context)) {
                 continue;
             }
@@ -291,6 +296,7 @@ class Course_ContentmodulesController extends AuthenticatedController
             $visibility = $tool ? $tool->getVisibilityPermission() : 'nobody';
 
             $metadata = $plugin->getMetadata();
+            $icon = $this->getIconFromMetadata($metadata, $plugin);
             $list[$plugin_id] = [
                 'id'             => $plugin_id,
                 'moduleclass'    => get_class($plugin),
@@ -299,7 +305,7 @@ class Course_ContentmodulesController extends AuthenticatedController
                 'displayname'    => $displayname,
                 'visibility'     => $visibility,
                 'active'         => (bool) $tool,
-                'icon'           => $this->getIconFromMetadata($metadata, $plugin),
+                'icon'           => $icon ? $icon->asImagePath() : null,
                 'summary'        => $metadata['summary'] ?? null,
                 'mandatory'      => $this->sem_class->isModuleMandatory(get_class($plugin)),
                 'highlighted'    => (bool) $plugin->isHighlighted(),
@@ -315,7 +321,7 @@ class Course_ContentmodulesController extends AuthenticatedController
      * @param array $metadata
      * @param CorePlugin|StudIPPlugin $plugin
      */
-    private function getIconFromMetadata(array $metadata, $plugin): ?string
+    private function getIconFromMetadata(array $metadata, $plugin): ?Icon
     {
         $icon = $metadata['icon_clickable'] ?? $metadata['icon'] ?? null;
 
@@ -332,7 +338,7 @@ class Course_ContentmodulesController extends AuthenticatedController
             $icon = Icon::create($plugin->getPluginURL() . '/' . $icon);
         }
 
-        return $icon->copyWithRole(Icon::ROLE_CLICKABLE)->asImagePath();
+        return $icon->copyWithRole(Icon::ROLE_CLICKABLE);
     }
 
     private function getCoreIcon(string $path): ?Icon
diff --git a/app/controllers/course/courseware.php b/app/controllers/course/courseware.php
index 22b124b..f0b873a 100644
--- a/app/controllers/course/courseware.php
+++ b/app/controllers/course/courseware.php
@@ -52,22 +52,20 @@ class Course_CoursewareController extends CoursewareController
 
     public function courseware_action($unit_id = null):  void
     {
-        global $user;
-
         Navigation::activateItem('course/courseware/unit');
         if ($this->unitsNotFound) {
             PageLayout::postMessage(MessageBox::info(_('Es wurde kein Lernmaterial gefunden.')));
             return;
         }
+        $user = User::findCurrent();
         $this->setCoursewareSidebar();
 
-        $this->user_id = $user->id;
         /** @var array<mixed> $last */
-        $last = UserConfig::get($this->user_id)->getValue('COURSEWARE_LAST_ELEMENT');
+        $last = UserConfig::get($user->id)->getValue('COURSEWARE_LAST_ELEMENT');
         $lastStructuralElement = \Courseware\StructuralElement::findOneById($last);
 
         if ($unit_id === null) {
-            if (isset($lastStructuralElement) && $lastStructuralElement->canVisit(User::findCurrent())) {
+            if (isset($lastStructuralElement) && $lastStructuralElement->canVisit($user)) {
                 $this->redirectToFirstUnit('course', Context::getId(), $last);
             } else {
                 $this->redirectToFirstUnit('course', Context::getId(), []);
diff --git a/app/controllers/course/dates.php b/app/controllers/course/dates.php
index a4e18e9..f64d66b 100644
--- a/app/controllers/course/dates.php
+++ b/app/controllers/course/dates.php
@@ -80,7 +80,10 @@ class Course_DatesController extends AuthenticatedController
             )->asDialog();
         }
 
-        if (Seminar::setInstance(new Seminar(Course::findCurrent()))->getSlotModule('documents') && CourseDateFolder::availableInRange(Course::findCurrent(), User::findCurrent()->id)) {
+        if (
+            Seminar::setInstance(new Seminar(Course::findCurrent()))->getSlotModule('documents')
+            && CourseDateFolder::availableInRange(Course::findCurrent(), User::findCurrent() ? User::findCurrent()->id : null)
+        ) {
             $actions->addLink(
                 _('Sitzungsordner anlegen'),
                 $this->url_for('course/dates/create_folders'),
diff --git a/app/controllers/course/details.php b/app/controllers/course/details.php
index 2a330e3..e1c9493 100644
--- a/app/controllers/course/details.php
+++ b/app/controllers/course/details.php
@@ -32,7 +32,7 @@ class Course_DetailsController extends AuthenticatedController
 
         $this->course = Course::find($course_id);
         if (!$this->course) {
-            throw new Trails_Exception(
+            throw new Trails\Exception(
                 404,
                 _('Es konnte keine Veranstaltung gefunden werden')
             );
diff --git a/app/controllers/course/enrolment.php b/app/controllers/course/enrolment.php
index eb4428e..420b5ca 100644
--- a/app/controllers/course/enrolment.php
+++ b/app/controllers/course/enrolment.php
@@ -37,7 +37,7 @@ class Course_EnrolmentController extends AuthenticatedController
             return false;
         }
         if (!get_object_type($this->course_id, ['sem'])) {
-            throw new Trails_Exception(400);
+            throw new Trails\Exception(400);
         }
         $course = Seminar::GetInstance($this->course_id);
         $enrolment_info = $course->getEnrolmentInfo($GLOBALS['user']->id);
diff --git a/app/controllers/course/forum/forum_controller.php b/app/controllers/course/forum/forum_controller.php
index 71d1aa0..65eec63 100644
--- a/app/controllers/course/forum/forum_controller.php
+++ b/app/controllers/course/forum/forum_controller.php
@@ -23,7 +23,7 @@ abstract class ForumController extends StudipController {
 
         parent::before_filter($action, $args);
 
-        $this->flash = Trails_Flash::instance();
+        $this->flash = Trails\Flash::instance();
 
         // Set help keyword for Stud.IP's user-documentation and page title
         PageLayout::setHelpKeyword('Basis.Forum');
diff --git a/app/controllers/course/gradebook/lecturers.php b/app/controllers/course/gradebook/lecturers.php
index b3b1f82..7ab02e7 100644
--- a/app/controllers/course/gradebook/lecturers.php
+++ b/app/controllers/course/gradebook/lecturers.php
@@ -258,7 +258,7 @@ class Course_Gradebook_LecturersController extends AuthenticatedController
     public function edit_custom_definition_action($definitionId)
     {
         if (!$this->definition = Definition::findOneBySQL('id = ? AND course_id = ?', [$definitionId, \Context::getId()])) {
-            throw new \Trails_Exception(404);
+            throw new \Trails\Exception(404);
         }
 
         // show template
@@ -271,7 +271,7 @@ class Course_Gradebook_LecturersController extends AuthenticatedController
     {
         CSRFProtection::verifyUnsafeRequest();
         if (!$definition = Definition::findOneBySQL('id = ? AND course_id = ?', [$definitionId, \Context::getId()])) {
-            throw new \Trails_Exception(404);
+            throw new \Trails\Exception(404);
         }
 
         $name = trim(\Request::get('name', ''));
diff --git a/app/controllers/course/grouping.php b/app/controllers/course/grouping.php
index 4f35b53..3cef673 100644
--- a/app/controllers/course/grouping.php
+++ b/app/controllers/course/grouping.php
@@ -36,6 +36,11 @@ class Course_GroupingController extends AuthenticatedController
         if (!$GLOBALS['perm']->have_studip_perm('tutor', $this->course->id)) {
             throw new AccessDeniedException(_('Sie haben leider nicht die notwendige Berechtigung für diese Aktion.'));
         }
+
+        if ($GLOBALS['perm']->have_studip_perm('admin', $this->course->id)) {
+            $widget = new CourseManagementSelectWidget();
+            Sidebar::get()->addWidget($widget);
+        }
     }
 
     /**
diff --git a/app/controllers/course/lti.php b/app/controllers/course/lti.php
index e0ca2cf..4db7776 100644
--- a/app/controllers/course/lti.php
+++ b/app/controllers/course/lti.php
@@ -1,4 +1,7 @@
 <?php
+
+use Studip\OAuth2\NegotiatesWithPsr7;
+
 /**
  * course/lti.php - LTI consumer API for Stud.IP
  *
@@ -13,6 +16,8 @@
 
 class Course_LtiController extends StudipController
 {
+    use NegotiatesWithPsr7;
+
     /**
      * Callback function being called before an action is executed.
      */
@@ -268,22 +273,15 @@ class Course_LtiController extends StudipController
      */
     public function save_link_action($tool_id)
     {
-        require_once 'vendor/oauth-php/library/OAuthRequestVerifier.php';
-
         $tool = LtiTool::find($tool_id);
         $lti_msg = Request::get('lti_msg');
         $lti_errormsg = Request::get('lti_errormsg');
         $content_items = Request::get('content_items');
         $content_items = json_decode($content_items, true);
 
-        OAuthStore::instance('PDO', [
-            'dsn' => 'mysql:host=' . $GLOBALS['DB_STUDIP_HOST'] . ';dbname=' . $GLOBALS['DB_STUDIP_DATABASE'],
-            'username' => $GLOBALS['DB_STUDIP_USER'],
-            'password' => $GLOBALS['DB_STUDIP_PASSWORD']
-        ]);
-
-        $oarv = new OAuthRequestVerifier();
-        $oarv->verifySignature($tool->consumer_secret, false, false);
+        if (!Studip\OAuth1::verifyRequest($this->getPsrRequest(), $tool->consumer_secret, '')) {
+            throw new Exception('Could not verify request.');
+        }
 
         if (is_array($content_items) && count($content_items['@graph'])) {
             // we only support selecting a single content item
@@ -452,18 +450,11 @@ class Course_LtiController extends StudipController
      */
     public function outcome_action($id)
     {
-        require_once 'vendor/oauth-php/library/OAuthRequestVerifier.php';
-
         $lti_data = LtiData::find($id);
 
-        OAuthStore::instance('PDO', [
-            'dsn' => 'mysql:host=' . $GLOBALS['DB_STUDIP_HOST'] . ';dbname=' . $GLOBALS['DB_STUDIP_DATABASE'],
-            'username' => $GLOBALS['DB_STUDIP_USER'],
-            'password' => $GLOBALS['DB_STUDIP_PASSWORD']
-        ]);
-
-        $oarv = new OAuthRequestVerifier();
-        $oarv->verifySignature($lti_data->getConsumerSecret(), false, false);
+        if (!Studip\OAuth1::verifyRequest($this->getPsrRequest(), $lti_data->getConsumerSecret(), '')) {
+            throw new Exception('Could not verify request.');
+        }
 
         // fetch and parse POST data
         $message = file_get_contents('php://input');
diff --git a/app/controllers/course/lvgselector.php b/app/controllers/course/lvgselector.php
index 3542a11..c8223a9 100644
--- a/app/controllers/course/lvgselector.php
+++ b/app/controllers/course/lvgselector.php
@@ -17,15 +17,13 @@ require 'config/mvv_config.php';
 
 class Course_LvgselectorController extends AuthenticatedController
 {
-
-    // see Trails_Controller#before_filter
     public function before_filter(&$action, &$args)
     {
         parent::before_filter($action, $args);
 
         $this->course = Course::findCurrent();
         if (!$this->course) {
-            throw new Trails_Exception(404, _('Es wurde keine Veranstaltung ausgewählt!'));
+            throw new Trails\Exception(404, _('Es wurde keine Veranstaltung ausgewählt!'));
         }
         $this->course_id = $this->course->id;
         if (!$GLOBALS['perm']->have_studip_perm('tutor', $this->course_id)) {
@@ -37,6 +35,11 @@ class Course_LvgselectorController extends AuthenticatedController
         $widget = new HelpbarWidget();
         $widget->addElement(new WidgetElement(_('Auf dieser Seite kann die Veranstaltung ausgewählten Lehrveranstaltungsgruppen zugeordnet werden.')));
         Helpbar::get()->addWidget($widget);
+
+        if ($GLOBALS['perm']->have_studip_perm('admin', $this->course_id)) {
+            $widget = new CourseManagementSelectWidget();
+            Sidebar::get()->addWidget($widget);
+        }
     }
 
     /**
diff --git a/app/controllers/course/members.php b/app/controllers/course/members.php
index 3eae083..1ec1587 100644
--- a/app/controllers/course/members.php
+++ b/app/controllers/course/members.php
@@ -232,7 +232,7 @@ class Course_MembersController extends AuthenticatedController
             $course_member = AdmissionApplication::find([$user_id, $this->course_id]);
         }
         if (is_null($course_member)) {
-            throw new Trails_Exception(400);
+            throw new Trails\Exception(400);
         }
         $this->comment = $course_member->comment;
         $this->user = User::find($user_id);
@@ -265,7 +265,7 @@ class Course_MembersController extends AuthenticatedController
             $course_member = AdmissionApplication::find([$user_id, $this->course_id]);
         }
         if (!Request::submitted('save') || is_null($course_member)) {
-            throw new Trails_Exception(400);
+            throw new Trails\Exception(400);
         }
         $course_member->comment = Request::get('comment');
 
diff --git a/app/controllers/course/messenger.php b/app/controllers/course/messenger.php
index 3e692aa..710ac87 100644
--- a/app/controllers/course/messenger.php
+++ b/app/controllers/course/messenger.php
@@ -12,16 +12,20 @@ class Course_MessengerController extends AuthenticatedController
 
     public function course_action($thread_id = null)
     {
-        if (Context::get()) {
-            PageLayout::setTitle(Context::get()->getFullName() . ' - ' . _('Blubber'));
+        $context = Context::get();
+
+        if (!$context) {
+            throw new CheckObjectException(_('Sie haben kein Objekt gewählt.'));
         }
 
         if (Navigation::hasItem('/course/blubber')) {
             Navigation::activateItem('/course/blubber');
         }
 
+        PageLayout::setTitle($context->getFullName() . ' - ' . _('Blubber'));
+
         $this->search = '';
-        $this->threads = BlubberThread::findByContext(Context::get()->id, true, Context::getType());
+        $this->threads = BlubberThread::findByContext($context->id, true, Context::getType());
         $this->thread = null;
         $this->threads_more_down = 0;
 
diff --git a/app/controllers/course/overview.php b/app/controllers/course/overview.php
index 96e7f5a..876de5a 100644
--- a/app/controllers/course/overview.php
+++ b/app/controllers/course/overview.php
@@ -58,8 +58,6 @@ class Course_OverviewController extends AuthenticatedController
 
         // Fetch  votes
         if (Config::get()->VOTE_ENABLE) {
-            $response             = $this->relay('evaluation/display/' . $this->course_id);
-            $this->evaluations    = $response->body;
             $response             = $this->relay('questionnaire/widget/' . $this->course_id);
             $this->questionnaires = $response->body;
         }
@@ -113,7 +111,7 @@ class Course_OverviewController extends AuthenticatedController
             $this->avatar   = StudygroupAvatar::getAvatar($this->course_id);
         }
 
-        $this->plugins = PluginEngine::getPlugins('StandardPlugin', $this->course_id);
+        $this->plugins = PluginEngine::getPlugins(StandardPlugin::class, $this->course_id);
 
         $sidebar = Sidebar::get();
 
diff --git a/app/controllers/course/room_requests.php b/app/controllers/course/room_requests.php
index ab802b7..b091047 100644
--- a/app/controllers/course/room_requests.php
+++ b/app/controllers/course/room_requests.php
@@ -46,7 +46,7 @@ class Course_RoomRequestsController extends AuthenticatedController
             SeminarCategories::GetBySeminarId($this->course_id)->studygroup_mode ||
             !$GLOBALS['perm']->have_studip_perm("tutor", $this->course_id)
         ) {
-            throw new Trails_Exception(400);
+            throw new Trails\Exception(400);
         }
 
         PageLayout::setHelpKeyword('Basis.VeranstaltungenVerwaltenAendernVonZeitenUndTerminen');
@@ -143,25 +143,15 @@ class Course_RoomRequestsController extends AuthenticatedController
         // a single date or whole course
         $this->request_range_id = Request::get('range_id', Context::getId());
 
-        if (!isset($_SESSION[$this->request_id])) {
-            $_SESSION[$this->request_id] = [];
-        }
+        $this->init_session();
         $_SESSION[$this->request_id]['range'] = $this->request_range ?: $_SESSION[$this->request_id]['range'] ?? null;
         $_SESSION[$this->request_id]['range_ids'] = $this->request_range_ids ?: [$this->request_range_id];
-        $_SESSION[$this->request_id]['search_by'] = '';
-        $_SESSION[$this->request_id]['room_category_id'] = '';
-        $_SESSION[$this->request_id]['room_id'] = '';
-        $_SESSION[$this->request_id]['room_name'] = '';
-        $_SESSION[$this->request_id]['selected_properties'] = [];
-
-        $this->request = null;
 
         // look for existing request or create a new one
         $this->request = new RoomRequest($this->request_id);
         // time ranges (start date, end date)
         $this->request->setRangeFields($_SESSION[$this->request_id]['range'], $_SESSION[$this->request_id]['range_ids']);
         $this->request_time_intervals = $this->request->getTimeIntervals();
-
     }
 
     /**
@@ -211,7 +201,6 @@ class Course_RoomRequestsController extends AuthenticatedController
                 );
             }
         }
-
     }
 
     /**
@@ -227,7 +216,6 @@ class Course_RoomRequestsController extends AuthenticatedController
                 _('Das Erstellen von Raumanfragen ist nicht erlaubt!')
             );
         }
-
         $this->request_id = $request_id;
         $this->step = (int)$step;
         $this->room_name = $_SESSION[$request_id]['room_name'];
@@ -266,15 +254,17 @@ class Course_RoomRequestsController extends AuthenticatedController
         $this->selected_room = Resource::find($_SESSION[$request_id]['room_id'] ?: $this->request->resource_id);
 
         $this->selected_room_category_id = $this->selected_room->category_id ?? $_SESSION[$request_id]['room_category_id'] ?? null;
+        $this->category = $this->selected_room_category_id ? ResourceCategory::find($this->selected_room_category_id) : null;
 
         $_SESSION[$request_id]['room_category_id'] = $_SESSION[$request_id]['room_category_id'] ?? $this->selected_room->category_id ?? null;
 
         // after selecting a room, go to next step or stay here if no room was selected at all
         if (Request::submitted('select_room')) {
             $this->selected_room_id = Request::get('selected_room_id');
+            $room = Room::find($this->selected_room_id);
             $_SESSION[$request_id]['room_id'] = $this->selected_room_id;
+            $_SESSION[$request_id]['room_category_id'] = $room->category_id;
             $_SESSION[$request_id]['select_room'] = true;
-
             $this->redirect(
                 'course/room_requests/request_check_properties/' . $this->request_id
             );
@@ -289,8 +279,6 @@ class Course_RoomRequestsController extends AuthenticatedController
             );
             return;
         }
-
-        // or we filter via category
         else if (Request::get('category_id') && Request::submitted('select_properties')) {
             $_SESSION[$request_id]['search_by'] = 'category';
             $_SESSION[$request_id]['room_category_id'] = Request::get('category_id');
@@ -299,74 +287,35 @@ class Course_RoomRequestsController extends AuthenticatedController
             );
             return;
         } else if (Request::submitted('reset_category')) {
-            //Delete all selected properties from the session since the category is reset
-            $_SESSION[$request_id]['selected_properties'] = [];
-            $_SESSION[$request_id]['room_category_id'] = '';
-            $_SESSION[$request_id]['room_name'] = '';
-            $_SESSION[$request_id]['room_id'] = '';
-            $this->redirect('course/room_requests/request_find_available_properties/' . $this->request_id . '/1');
+            $this->init_session();
+            $this->redirect('course/room_requests/new_request');
             return;
         }
 
         // for step 2: after choosing a specific room OR searching via properties
         if ($this->step === 2) {
-            if ($_SESSION[$request_id]['search_by'] == 'roomname') {
-                // find category via room
-                $this->category = ResourceCategory::find($this->selected_room_category_id);
-                if ($this->category) {
-                    $this->available_properties = $this->category->getRequestableProperties();
-                }
-
-                $this->selected_properties = $_SESSION[$request_id]['selected_properties'];
-                $this->room = Room::find($_SESSION[$request_id]['room_id']);
-                $this->selected_properties['seats'] = $_SESSION[$request_id]['selected_properties']['seats']
-                    ?: $this->course->admission_turnout
-                    ?: Config::get()->RESOURCES_ROOM_REQUEST_DEFAULT_SEATS;
-                $_SESSION[$request_id]['selected_properties']['seats'] = $this->selected_properties['seats'];
-            } else if ($_SESSION[$request_id]['search_by'] === 'category') {
+            if (!empty(Request::getArray('selected_properties'))) {
+                $this->selected_properties = Request::getArray('selected_properties');
+            } else {
+                $this->selected_properties =  $_SESSION[$request_id]['selected_properties'];
+            }
+            $_SESSION[$request_id]['selected_properties'] = $this->selected_properties;
+            if ($_SESSION[$request_id]['search_by'] === 'roomname') {
+                $this->selected_properties = $_SESSION[$request_id]['selected_properties'] ?? null;
                 $this->room = Room::find($_SESSION[$request_id]['room_id']);
-                if ($this->room) {
-                    $this->grouped_properties = $this->room->getGroupedProperties();
-                    foreach ($this->grouped_properties as $properties) {
-                        foreach ($properties as $property) {
-                            $this->selected_properties[$property->name] = $property->state;
-                        }
-                    }
+                if (!isset($_SESSION[$request_id]['selected_properties']['seats'])) {
+                    $this->selected_properties['seats'] = $this->course->admission_turnout ?? Config::get()->RESOURCES_ROOM_REQUEST_DEFAULT_SEATS;
                 }
-
+                $_SESSION[$request_id]['selected_properties']['seats'] = $this->selected_properties['seats'];
+                $_SESSION[$request_id]['room_category_id'] = $this->selected_room_category_id;
+            } else {
+                // let's find all the properties belonging to the selected category
+                $this->room_category_id = $_SESSION[$request_id]['room_category_id'];
             }
 
-            // find rooms fitting to category and properties
-            if (Request::submitted('search_rooms')) {
-                $this->selected_properties = Request::getArray('selected_properties');
-                $_SESSION[$request_id]['selected_properties'] = $this->selected_properties;
-                // no min number of seats
-                if (
-                    (!$_SESSION[$request_id]['selected_properties']['seats'] || $_SESSION[$request_id]['selected_properties']['seats'] < 1)
-                    && $_SESSION[$request_id]['search_by'] === 'category'
-                ) {
-                    PageLayout::postError(
-                        _('Die Mindestanzahl der Sitzplätze beträgt 1!')
-                    );
-                    $this->redirect(
-                        'course/room_requests/request_find_matching_rooms/' . $request_id . '/' . $this->step
-                    );
-                    return;
-                } else {
-                    $this->redirect(
-                        'course/room_requests/request_find_matching_rooms/' . $request_id . '/' . $this->step
-                    );
-                    return;
-                }
+            if ($this->category) {
+                $this->available_properties = $this->category->getRequestableProperties();
             }
-
-            // let's find all the properties belonging to the selected category
-            $this->room_category_id = $_SESSION[$request_id]['room_category_id'];
-            $this->category = ResourceCategory::find($this->room_category_id);
-            $this->available_properties = $this->category->getRequestableProperties();
-
-            // properties, like 'Sitzplätze', 'behindertengerecht' etc
-            $this->selected_properties = $_SESSION[$request_id]['selected_properties'] ?? null;
             $this->preparation_time = $_SESSION[$request_id]['preparation_time'] ?? null;
             $this->comment = $_SESSION[$request_id]['comment'] ?? null;
             $this->request->category_id = $_SESSION[$request_id]['room_category_id'];
@@ -375,7 +324,10 @@ class Course_RoomRequestsController extends AuthenticatedController
             if (Request::submitted('show_summary')) {
                 $this->selected_room_id = Request::get('selected_room_id');
                 $_SESSION[$request_id]['room_id'] = $this->selected_room_id;
-                $_SESSION[$request_id]['selected_properties'] = Request::getArray('selected_properties');
+                $room = Room::find($this->selected_room_id);
+                if ($room) {
+                    $_SESSION[$request_id]['room_category_id'] = $room->category_id;
+                }
                 $this->redirect('course/room_requests/request_show_summary/' . $this->request_id );
             }
         }
@@ -394,16 +346,18 @@ class Course_RoomRequestsController extends AuthenticatedController
                 _('Das Erstellen von Raumanfragen ist nicht erlaubt!')
             );
         }
-
         $this->request_id = $request_id;
         $this->step = (int)$step;
 
         $this->request = new RoomRequest($this->request_id);
-        $this->request->setRangeFields($_SESSION[$this->request_id]['range'], $_SESSION[$this->request_id]['range_ids']);
+        $this->request->setRangeFields(
+            $_SESSION[$this->request_id]['range'] ?? null,
+            $_SESSION[$this->request_id]['range_ids'] ?? null
+        );
 
         // let's find all the properties belonging to the selected category
         $this->room_category_id = $_SESSION[$request_id]['room_category_id'] ?: $this->request->category_id;
-        $this->room_name = $_SESSION[$request_id]['room_name'];
+        $this->room_name = $_SESSION[$request_id]['room_name'] ?? '';
         $this->selected_room = Resource::find($_SESSION[$request_id]['room_id'] ?: $this->request->resource_id);
         $this->category = $this->room_category_id ? ResourceCategory::find($this->room_category_id) : '';
         $this->available_properties = $this->room_category_id ? $this->category->getRequestableProperties() : '';
@@ -418,7 +372,10 @@ class Course_RoomRequestsController extends AuthenticatedController
         $this->comment = $_SESSION[$request_id]['comment'] ?? null;
 
         // when searching for a room name, list found room
-        if ($_SESSION[$request_id]['room_name'] !== '') {
+        if (
+            isset($_SESSION[$request_id]['room_name'])
+            && $_SESSION[$request_id]['room_name'] !== ''
+        ) {
             $search_properties['room_category_id'] = $this->room_category_id;
             $search_properties['seats'] = [
                 1,
@@ -455,11 +412,13 @@ class Course_RoomRequestsController extends AuthenticatedController
         }
 
         $this->request_id = $request_id;
-
+        $this->selected_properties = Request::getArray('selected_properties');
         // select a room, search for a room name or search for rooms matching properties
         if (Request::submitted('select_room')) {
             $this->selected_room_id = Request::get('selected_room_id');
+            $room = Room::find($this->selected_room_id);
             $_SESSION[$request_id]['room_id'] = $this->selected_room_id;
+            $_SESSION[$request_id]['room_category_id'] = $room->category_id;
             $_SESSION[$request_id]['select_room'] = true;
             $this->step = 2;
             $this->request = new RoomRequest($this->request_id);
@@ -467,7 +426,6 @@ class Course_RoomRequestsController extends AuthenticatedController
                 'course/room_requests/request_find_matching_rooms/' . $this->request_id . '/' . $this->step
             );
         } else if (Request::get('room_name') && Request::submitted('search_by_name')) {
-            $this->selected_properties = Request::getArray('selected_properties');
             $this->category_id = Request::get('category_id');
             $_SESSION[$request_id]['selected_properties'] = $this->selected_properties;
             $_SESSION[$request_id]['room_category_id'] = $this->category_id;
@@ -479,7 +437,6 @@ class Course_RoomRequestsController extends AuthenticatedController
             );
 
         } else if (Request::submitted('search_rooms')) {
-            $this->selected_properties = Request::getArray('selected_properties');
             $this->category_id = Request::get('category_id');
             $_SESSION[$request_id]['room_category_id'] = $this->category_id;
             $_SESSION[$request_id]['selected_properties'] = $this->selected_properties;
@@ -506,8 +463,7 @@ class Course_RoomRequestsController extends AuthenticatedController
             }
         } else if (Request::submitted('reset_category')) {
             //Delete all selected properties from the session since the category is reset
-            $_SESSION[$request_id]['selected_properties'] = [];
-            $_SESSION[$request_id]['room_category_id'] = '';
+            $this->init_session();
             $this->redirect('course/room_requests/request_find_available_properties/' . $this->request_id . '/1');
         } else if (Request::submitted('search_by_category')) {
             if (Request::get('category_id') === '0') {
@@ -521,12 +477,11 @@ class Course_RoomRequestsController extends AuthenticatedController
             );
         } else if (Request::submitted('show_summary')) {
             $this->request = new RoomRequest($this->request_id);
-            $this->selected_properties = Request::getArray('selected_properties');
-
-            $_SESSION[$request_id]['selected_properties'] = $this->selected_properties;
             $this->selected_room_id = Request::get('selected_room_id');
+            $room = Room::find($this->selected_room_id);
             $_SESSION[$request_id]['room_id'] = $this->selected_room_id;
-
+            $_SESSION[$request_id]['room_category_id'] = $room->category_id ?? $_SESSION[$request_id]['room_category_id'];
+            $_SESSION[$request_id]['selected_properties'] = $this->selected_properties;
             $this->redirect('course/room_requests/request_show_summary/' . $this->request_id  );
         } else {
             $room = Room::find($_SESSION[$request_id]['room_id']);
@@ -569,7 +524,6 @@ class Course_RoomRequestsController extends AuthenticatedController
         );
 
         $this->selected_room_category = ResourceCategory::find($_SESSION[$request_id]['room_category_id'] ?? $this->request->category_id);
-
         $this->selected_room = Resource::find($_SESSION[$request_id]['room_id'] ?? $this->request->resource_id);
 
         $this->room_id = $_SESSION[$request_id]['room_id'] ?? $this->request->resource_id;
@@ -592,7 +546,7 @@ class Course_RoomRequestsController extends AuthenticatedController
 
         $_SESSION[$request_id]['search_by'] = $this->selected_room ? 'roomname' : 'category';
         $_SESSION[$request_id]['room_category_id'] = $this->selected_room_category->id;
-        $_SESSION[$request_id]['room_id'] = $this->selected_room->id;
+        $_SESSION[$request_id]['room_id'] = $this->selected_room ? $this->selected_room->id : '';
     }
 
     public function store_request_action($request_id)
@@ -629,8 +583,12 @@ class Course_RoomRequestsController extends AuthenticatedController
             $this->request->store();
 
             //Store the properties:
-            foreach ($_SESSION[$request_id]['selected_properties'] as $name => $state) {
-                $this->request->setProperty($name, $state);
+            if (isset($_SESSION[$request_id]['selected_properties'])) {
+                foreach ($_SESSION[$request_id]['selected_properties'] as $name => $state) {
+                    if (!empty($state)) {
+                        $this->request->setProperty($name, $state);
+                    }
+                }
             }
 
             // once stored, we can delete the session data for this request
@@ -707,7 +665,7 @@ class Course_RoomRequestsController extends AuthenticatedController
     {
         $request = RoomRequest::find($request_id);
         if (!$request) {
-            throw new Trails_Exception(403);
+            throw new Trails\Exception(403);
         }
         if (Request::isGet()) {
             PageLayout::postQuestion(sprintf(
@@ -723,4 +681,19 @@ class Course_RoomRequestsController extends AuthenticatedController
         }
         $this->redirect('course/timesrooms/index');
     }
+
+    private function init_session()
+    {
+        $_SESSION[$this->request_id] = array_merge(
+            $_SESSION[$this->request_id] ?? [],
+            [
+                'search_by'           => '',
+                'room_category_id'    => '',
+                'room_id'             => '',
+                'room_name'           => '',
+                'select_room'         => false,
+                'selected_properties' => [],
+            ]
+        );
+    }
 }
diff --git a/app/controllers/course/scm.php b/app/controllers/course/scm.php
index 66af981..4c5d4eb 100644
--- a/app/controllers/course/scm.php
+++ b/app/controllers/course/scm.php
@@ -93,7 +93,7 @@ class Course_ScmController extends AuthenticatedController
         $this->scm  = $id ? $this->scms->find($id) : $this->scms->first();
 
         if (!$this->scm && $this->scms->count() > 0) {
-            throw new Trails_Exception(404, _('Es konnte keine freie Informationsseite mit der angegebenen Id gefunden werden.'));
+            throw new Trails\Exception(404, _('Es konnte keine freie Informationsseite mit der angegebenen Id gefunden werden.'));
         }
 
         if (Request::get('verify') === 'delete') {
diff --git a/app/controllers/course/statusgroups.php b/app/controllers/course/statusgroups.php
index c15733d..6f96299 100644
--- a/app/controllers/course/statusgroups.php
+++ b/app/controllers/course/statusgroups.php
@@ -762,7 +762,7 @@ class Course_StatusgroupsController extends AuthenticatedController
 
             // Safety check if no group_id at all.
             if (!$group_id) {
-                throw new Trails_Exception(400);
+                throw new Trails\Exception(400);
             }
         }
 
@@ -1487,4 +1487,20 @@ class Course_StatusgroupsController extends AuthenticatedController
         return $members->orderBy($order);
 
     }
+
+    public function details_action(Statusgruppen $group): void
+    {
+        $course = Course::findCurrent();
+
+        if ($course->id !== $group->range_id) {
+            throw new AccessDeniedException();
+        }
+
+        PageLayout::setTitle(sprintf(
+            _('Personen der Gruppe %s'),
+            $group->name
+        ));
+
+        $this->group = $group;
+    }
 }
diff --git a/app/controllers/course/study_areas.php b/app/controllers/course/study_areas.php
index df54bb4..e951d11 100644
--- a/app/controllers/course/study_areas.php
+++ b/app/controllers/course/study_areas.php
@@ -18,7 +18,6 @@ require_once 'lib/webservices/api/studip_lecture_tree.php';
 
 class Course_StudyAreasController extends AuthenticatedController
 {
-    // see Trails_Controller#before_filter
     public function before_filter(&$action, &$args)
     {
         parent::before_filter($action, $args);
@@ -101,7 +100,7 @@ class Course_StudyAreasController extends AuthenticatedController
     public function save_action()
     {
         if($this->locked) {
-            throw new Trails_Exception(403);
+            throw new Trails\Exception(403);
         }
 
         $params = [];
diff --git a/app/controllers/course/studygroup.php b/app/controllers/course/studygroup.php
index b75d91e..cd08ba3 100644
--- a/app/controllers/course/studygroup.php
+++ b/app/controllers/course/studygroup.php
@@ -10,8 +10,6 @@ require_once 'lib/user_visible.inc.php';
  */
 class Course_StudygroupController extends AuthenticatedController
 {
-
-    // see Trails_Controller#before_filter
     public function before_filter(&$action, &$args)
     {
         parent::before_filter($action, $args);
@@ -596,6 +594,11 @@ class Course_StudygroupController extends AuthenticatedController
         global $perm;
 
         $id = Context::getId();
+
+        if (!$id) {
+            throw new CheckObjectException(_('Sie haben kein Objekt gewählt.'));
+        }
+
         $user = Request::username('user');
 
         if ($from_status === 'moderator') {
@@ -780,7 +783,7 @@ class Course_StudygroupController extends AuthenticatedController
             // send invite message to user
             $msg     = new messaging();
             $sem     = new Seminar($id);
-            $message = sprintf(_("%s möchte Sie auf die Studiengruppe %s aufmerksam machen. Klicken Sie auf den untenstehenden Link, um direkt zur Studiengruppe zu gelangen.\n\n %s"),
+            $message = sprintf(_("%s möchte Sie auf die Studiengruppe %s aufmerksam machen. Klicken Sie auf den folgenden Link, um direkt zur Studiengruppe zu gelangen.\n\n %s"),
                 get_fullname(), $sem->name, URLHelper::getlink("dispatch.php/course/studygroup/details/" . $id, ['cid' => null]));
             $subject = _("Sie wurden in eine Studiengruppe eingeladen");
             $msg->insert_message($message, get_username($receiver), '', '', '', '', '', $subject);
@@ -846,7 +849,7 @@ class Course_StudygroupController extends AuthenticatedController
                 return;
             }
         }
-        throw new Trails_Exception(401);
+        throw new Trails\Exception(401);
     }
 
 
diff --git a/app/controllers/course/timesrooms.php b/app/controllers/course/timesrooms.php
index 2e3b3fe..4788eee 100644
--- a/app/controllers/course/timesrooms.php
+++ b/app/controllers/course/timesrooms.php
@@ -14,7 +14,7 @@ class Course_TimesroomsController extends AuthenticatedController
      * @param String $action Action to be executed
      * @param Array  $args Arguments passed to the action
      *
-     * @throws Trails_Exception when either no course was found or the user
+     * @throws Trails\Exception when either no course was found or the user
      *                          may not access this area
      */
     public function before_filter(&$action, &$args)
@@ -23,7 +23,7 @@ class Course_TimesroomsController extends AuthenticatedController
 
         // Try to find a valid course
         if (!Course::findCurrent()) {
-            throw new Trails_Exception(404, _('Es wurde keine Veranstaltung ausgewählt!'));
+            throw new Trails\Exception(404, _('Es wurde keine Veranstaltung ausgewählt!'));
         }
 
         if (!$GLOBALS['perm']->have_studip_perm('tutor', Course::findCurrent()->id)) {
@@ -250,7 +250,7 @@ class Course_TimesroomsController extends AuthenticatedController
     /**
      * Edit the start-semester of a course
      *
-     * @throws Trails_DoubleRenderError
+     * @throws Trails\Exceptions\DoubleRenderError
      */
     public function editSemester_action()
     {
@@ -331,11 +331,6 @@ class Course_TimesroomsController extends AuthenticatedController
         $this->date       = CourseDate::find($termin_id) ?: CourseExDate::find($termin_id);
         $this->attributes = [];
 
-        if ($request = RoomRequest::findByDate($this->date->id)) {
-            $this->params = ['request_id' => $request->getId()];
-        } else {
-            $this->params = ['new_room_request_type' => 'date_' . $this->date->id];
-        }
         $this->only_bookable_rooms = Request::submitted('only_bookable_rooms');
 
         if (Config::get()->RESOURCES_ENABLE) {
@@ -373,7 +368,7 @@ class Course_TimesroomsController extends AuthenticatedController
      *
      * @param $termin_id
      *
-     * @throws Trails_DoubleRenderError
+     * @throws Trails\Exceptions\DoubleRenderError
      */
     public function saveDate_action($termin_id)
     {
@@ -439,7 +434,7 @@ class Course_TimesroomsController extends AuthenticatedController
         }
 
         // Set assigned groups
-        $assigned_groups       = Request::optionArray('assigned_groups');
+        $assigned_groups       = Request::optionArray('assigned-groups');
         $termin->statusgruppen = Statusgruppen::findMany($assigned_groups);
 
         $termin->store();
@@ -449,7 +444,11 @@ class Course_TimesroomsController extends AuthenticatedController
         }
 
         // Set Room
-        $old_room_id = $termin->room_booking->resource_id;
+        if ($termin->room_booking) {
+            $old_room_id = $termin->room_booking->resource_id;
+        } else {
+            $old_room_id = null;
+        }
         $singledate = new SingleDate($termin);
         if ($singledate->setTime($date, $end_time)) {
             $singledate->store();
@@ -517,7 +516,7 @@ class Course_TimesroomsController extends AuthenticatedController
                 '<strong>' . htmlReady($singledate->toString()) . '</strong>'
             ));
         }
-        if ($singledate->messages['error']) {
+        if (!empty($singledate->messages['error'])) {
             PageLayout::postError(
                 _('Die folgenden Fehler traten beim Bearbeiten des Termins auf:'),
                 htmlReady($singledate->messages['error'])
@@ -549,7 +548,7 @@ class Course_TimesroomsController extends AuthenticatedController
     /**
      * Save Single Date
      *
-     * @throws Trails_DoubleRenderError
+     * @throws Trails\Exceptions\DoubleRenderError
      */
     public function saveSingleDate_action()
     {
@@ -1490,23 +1489,10 @@ class Course_TimesroomsController extends AuthenticatedController
         }
         Sidebar::Get()->addWidget($widget);
 
-        if ($GLOBALS['perm']->have_perm('admin')) {
-            $list = new SelectWidget(
-                _('Veranstaltungen'),
-                $this->indexURL(),
-                'cid'
-            );
 
-            foreach (AdminCourseFilter::get()->getCoursesForAdminWidget() as $seminar) {
-                $list->addElement(new SelectElement(
-                    $seminar['Seminar_id'],
-                    $seminar['Name'],
-                    $seminar['Seminar_id'] === Context::getId(),
-                    $seminar['VeranstaltungsNummer'] . ' ' . $seminar['Name']
-                ));
-            }
-            $list->size = 8;
-            Sidebar::Get()->addWidget($list);
+        if ($GLOBALS['perm']->have_studip_perm('admin', $this->course->id)) {
+            $widget = new CourseManagementSelectWidget();
+            Sidebar::get()->addWidget($widget);
         }
     }
 
@@ -1701,7 +1687,7 @@ class Course_TimesroomsController extends AuthenticatedController
             } else {
                 $user_rooms = RoomManager::getUserRooms($current_user);
                 foreach ($user_rooms as $room) {
-                    if ($room->userHasBookingRights($current_user, $begin, $end)) {
+                    if ($room->userHasBookingRights($current_user, $begin ?? null, $end ?? null)) {
                         $rooms_with_booking_permissions++;
                         if ($only_bookable_rooms) {
                             foreach ($all_time_intervals as $interval) {
diff --git a/app/controllers/course/wiki.php b/app/controllers/course/wiki.php
index 7a3a09e..4de56a7 100644
--- a/app/controllers/course/wiki.php
+++ b/app/controllers/course/wiki.php
@@ -18,7 +18,7 @@ class Course_WikiController extends AuthenticatedController
         parent::before_filter($action, $args);
         object_set_visit_module('wiki');
         $this->range = Context::get();
-        $this->plugin = PluginManager::getInstance()->getPlugin('CoreWiki');
+        $this->plugin = PluginManager::getInstance()->getPlugin(CoreWiki::class);
 
         PageLayout::setTitle(Navigation::getItem('/course/wiki')->getTitle());
     }
@@ -117,8 +117,9 @@ class Course_WikiController extends AuthenticatedController
         $startPage = WikiPage::find($this->range->getConfiguration()->WIKI_STARTPAGE_ID);
         $this->contentbar = ContentBar::get()
             ->setTOC(CoreWiki::getTOC($this->page))
-            ->setIcon(Icon::create('wiki'))
-            ->setInfo(sprintf(
+            ->setIcon(Icon::create('wiki'));
+        if (!$this->page->isNew()) {
+            $this->contentbar->setInfo(sprintf(
                 _('Version %1$s, geändert von %2$s <br> am %3$s'),
                 $this->page->versionnumber,
                 sprintf(
@@ -128,33 +129,44 @@ class Course_WikiController extends AuthenticatedController
                 ),
                 date('d.m.Y H:i:s', $this->page['chdate'])
             ));
-        $action_menu = ActionMenu::get();
-        if ($this->page->isEditable()) {
-            $action_menu->addLink(
-                $this->editURL($this->page),
-                _('Bearbeiten'),
-                Icon::create('edit')
-            );
+            $action_menu = ActionMenu::get();
+            if ($this->page->isEditable()) {
+                $action_menu->addLink(
+                    $this->editURL($this->page),
+                    _('Bearbeiten'),
+                    Icon::create('edit')
+                );
+                $action_menu->addLink(
+                    $this->pagesettingsURL($this->page->id),
+                    _('Seiteneinstellungen'),
+                    Icon::create('settings'),
+                    ['data-dialog' => 'width=700']
+                );
+                if (count($this->page->versions) > 0) {
+                    $action_menu->addLink(
+                        $this->ask_deletingURL($this->page),
+                        _('Seite / Version löschen'),
+                        Icon::create('trash'),
+                        ['data-dialog' => 'size=auto']
+                    );
+                } else {
+                    $action_menu->addButton(
+                        'delete',
+                        _('Seite löschen'),
+                        Icon::create('trash'),
+                        ['data-confirm' => _('Wollen Sie wirklich die komplette Seite löschen?'), 'form' => 'delete_page']
+                    );
+                }
+            }
             $action_menu->addLink(
-                $this->pagesettingsURL($this->page->id),
-                _('Seiteneinstellungen'),
-                Icon::create('settings'),
-                ['data-dialog' => 'width=700']
-            );
-            $action_menu->addButton(
-                'delete',
-                _('Seite löschen'),
-                Icon::create('trash'),
-                ['data-confirm' => _('Wollen Sie wirklich die komplette Seite löschen?'), 'form' => 'delete_page']
+                '#',
+                _('Als Vollbild anzeigen'),
+                Icon::create('screen-full'),
+                ['class' => 'fullscreen-trigger hidden-medium-down']
             );
+            $this->contentbar->setActionMenu($action_menu);
         }
-        $action_menu->addLink(
-            '#',
-            _('Als Vollbild anzeigen'),
-            Icon::create('screen-full'),
-            ['class' => 'fullscreen-trigger hidden-medium-down']
-        );
-        $this->contentbar->setActionMenu($action_menu);
+
     }
 
     public function pagesettings_action(WikiPage $page)
@@ -253,7 +265,10 @@ class Course_WikiController extends AuthenticatedController
                     "[[ " . $values['name'],
                     $p2['content']
                 );
-                $p2->store();
+                if ($p2->isDirty()) {
+                    $p2['user_id'] = User::findCurrent()->id;
+                    $p2->store();
+                }
             }
         })->validate();
         if (Request::isPost()) {
@@ -269,9 +284,17 @@ class Course_WikiController extends AuthenticatedController
         $this->render_form($this->form);
     }
 
+    public function ask_deleting_action(WikiPage $page)
+    {
+        if (!$page->isEditable()) {
+            throw new AccessDeniedException();
+        }
+        PageLayout::setTitle(_('Was genau soll gelöscht werden?'));
+    }
+
     public function delete_action(WikiPage $page)
     {
-        if (!Request::isPost() || !CSRFProtection::verifyRequest()) {
+        if (!Request::isPost() || !$page->isEditable() || !CSRFProtection::verifyRequest()) {
             throw new AccessDeniedException();
         }
         $name = $page->name;
@@ -280,13 +303,52 @@ class Course_WikiController extends AuthenticatedController
         $this->redirect($this->allpagesURL());
     }
 
+    public function deleteversion_action(WikiPage $page, $version_id = null)
+    {
+        if (!Request::isPost() || !$page->isEditable() || !CSRFProtection::verifyRequest()) {
+            throw new AccessDeniedException();
+        }
+        if ($version_id === null) {
+            $version = $page->versions[0];
+            if ($version) {
+                $page['name'] = $version['name'];
+                $page['content'] = $version['content'];
+                $page['user_id'] = $version['user_id'];
+                $page['chdate'] = $version['mkdate'];
+                $page->store();
+                $version->delete();
+            } else {
+                $page->delete();
+            }
+        } else {
+            $version = WikiVersion::find($version_id);
+            if ($version['page_id'] === $page->id) {
+                $version->delete();
+            }
+        }
+        PageLayout::postSuccess(_('Version wurde gelöscht.'));
+        if (Request::get('redirect_to') === 'page') {
+            $this->redirect($this->page($page));
+        } else {
+            $this->redirect($this->history($page));
+        }
+
+    }
+
     public function allpages_action()
     {
-        Navigation::activateItem('/course/wiki/allpages');
         $this->pages = WikiPage::findBySQL(
             "`range_id` = ? ORDER BY `name` ASC",
             [$this->range->id]
         );
+
+        if (count($this->pages) === 0) {
+            $this->redirect($this->pageURL());
+            return;
+        }
+
+        Navigation::activateItem('/course/wiki/allpages');
+
         if ($GLOBALS['perm']->have_studip_perm('tutor', $this->range->id)) {
             $actions = new ActionsWidget();
             $actions->addLink(
@@ -379,7 +441,7 @@ class Course_WikiController extends AuthenticatedController
             $this->redirect($this->editURL($page));
             return;
         }
-        if (!$page->isEditable()) {
+        if ($page->isNew() || !$page->isEditable()) {
             throw new AccessDeniedException();
         }
         Navigation::activateItem('/course/wiki/start');
@@ -393,7 +455,7 @@ class Course_WikiController extends AuthenticatedController
         );
         $pageData = [
             'page_id' => $page->id,
-            'user_id' => $user->id
+            'user_id' => $user ? $user->id : null,
         ];
         $online_user = WikiOnlineEditingUser::findOneBySQL(
             '`page_id` = :page_id AND `user_id` = :user_id',
@@ -404,7 +466,7 @@ class Course_WikiController extends AuthenticatedController
         }
         $editingUsers = WikiOnlineEditingUser::countBySQL(
             "`page_id` = ? AND `editing` = 1 AND `user_id` != ?",
-            [$page->id, $user->id]
+            [$page->id, $user ? $user->id : null]
         );
         $online_user->editing = $editingUsers === 0 ? 1 : 0;
         $online_user->chdate = time();
@@ -501,6 +563,7 @@ class Course_WikiController extends AuthenticatedController
             $this->render_json([
                 'error' => 'user_not_requested_edit_mode'
             ]);
+            return;
         }
 
         $online_user_me->editing = 0;
@@ -524,7 +587,19 @@ class Course_WikiController extends AuthenticatedController
         }
 
         $page->content = \Studip\Markup::markAsHtml(trim(Request::get('content')));
-        $page->store();
+        $user = User::findCurrent();
+        if ($page->isDirty()) {
+            $page['user_id'] = $user->id;
+            $page->store();
+        }
+        $pageData = [
+            'page_id' => $page->id,
+            'user_id' => $user->id
+        ];
+        WikiOnlineEditingUser::deleteBySQL(
+            '`page_id` = :page_id AND `user_id` = :user_id',
+            $pageData
+        );
         PageLayout::postSuccess(_('Die Seite wurde gespeichert.'));
         $this->redirect($this->pageURL($page));
     }
@@ -560,7 +635,7 @@ class Course_WikiController extends AuthenticatedController
         $statement->execute([
             'range_id' => $this->range->id,
             'threshold' => $this->last_visit,
-            'me' => User::findCurrent()->id
+            'me' => User::findCurrent() ? User::findCurrent()->id : null
         ]);
         $this->num_entries = $statement->fetch(PDO::FETCH_COLUMN);
         $this->pagenumber = Request::int('page', 0);
@@ -754,6 +829,10 @@ class Course_WikiController extends AuthenticatedController
                         'type' => 'no',
                         'mapper' => function () { return $this->range->id; }
                     ],
+                    'user_id' => [
+                        'type' => 'no',
+                        'mapper' => function () { return User::findCurrent()->id; }
+                    ],
                     'name' => [
                         'required' => true,
                         'label' => _('Name der Seite'),
@@ -808,7 +887,10 @@ class Course_WikiController extends AuthenticatedController
                             '[[ ' . $values['name'] . ' ]]',
                             $page->content
                         );
-                        $page->store();
+                        if ($page->isDirty()) {
+                            $page['user_id'] = User::findCurrent()->id;
+                            $page->store();
+                        }
                     }
                 }
             }
@@ -894,6 +976,30 @@ class Course_WikiController extends AuthenticatedController
         Sidebar::Get()->addWidget($search);
     }
 
+    public function searchpage_action(WikiPage $page)
+    {
+        if (!$page->isReadable()) {
+            throw new AccessDeniedException();
+        }
+        Navigation::activateItem('/course/wiki/allpages');
+        if (!Request::get('search')) {
+            throw new Exception('No search text.');
+        }
+        $search = str_replace(['\\', '_', '%'], ['\\\\', '\\_', '\\%'], Request::get('search'));
+        $this->versions = WikiVersion::findBySQL("`page_id` = :page_id AND (`wiki_versions`.`content` LIKE :searchterm OR `wiki_versions`.`name` LIKE :searchterm) ORDER BY `mkdate` DESC ", [
+            'page_id' => $page->id,
+            'searchterm' => '%' . $search . '%'
+        ]);
+
+        $search = new SearchWidget($this->searchURL());
+        $search->addNeedle(
+            _('Im Wiki suchen'),
+            'search',
+            true
+        );
+        Sidebar::Get()->addWidget($search);
+    }
+
     public function pdf_action(WikiPage $page)
     {
         if (!$page->isReadable()) {
@@ -1135,4 +1241,41 @@ class Course_WikiController extends AuthenticatedController
 
         return $from_end ? mb_strlen($str0) - $length : $length;
     }
+
+    public function findTextualHits($text, $search, $length = 80)
+    {
+        $content = Studip\Markup::removeHtml($text);
+        $offset  = 0;
+        $output  = [];
+
+        // find all occurences
+        while ($offset < mb_strlen($content)) {
+            $pos = mb_stripos($content, Request::get('search'), $offset);
+            if ($pos === false) {
+                break;
+            }
+            $offset = $pos + 1;
+
+            // show max 200 chars
+            $fragment       = '';
+            $split_fragment = preg_split(
+                '/(' . preg_quote(Request::get('search'), '/') . ')/i',
+                mb_substr($content, max(0, $pos - floor($length / 2)), $length),
+                -1,
+                PREG_SPLIT_DELIM_CAPTURE
+            );
+            for ($i = 0; $i < count($split_fragment); ++$i) {
+                if ($i % 2) {
+                    $fragment .= '<span class="wiki_highlight">';
+                    $fragment .= htmlready($split_fragment[$i], false);
+                    $fragment .= '</span>';
+                } else {
+                    $fragment .= htmlready($split_fragment[$i], false);
+                }
+            }
+            $found_in_fragment = (count($split_fragment) - 1) / 2; // number of hits in fragment
+            $output[]          = '...' . $fragment . '...';
+        }
+        return implode('<br>', $output);
+    }
 }
diff --git a/app/controllers/course/wizard.php b/app/controllers/course/wizard.php
index b45f9e5..c1571ad 100644
--- a/app/controllers/course/wizard.php
+++ b/app/controllers/course/wizard.php
@@ -25,14 +25,9 @@ class Course_WizardController extends AuthenticatedController
     public function before_filter (&$action, &$args)
     {
         parent::before_filter($action, $args);
-        global $perm;
-        if (Request::isXhr()) {
-            $this->dialog = true;
-        }
-
-        $sidebar = Sidebar::get();
 
-        $this->studygroup = Request::int('studygroup') ?: $this->flash['studygroup'];
+        $this->dialog = Request::isXhr();
+        $this->studygroup = Request::bool('studygroup', $this->flash['studygroup'] ?? false);
 
         if (!$this->studygroup) {
             PageLayout::setTitle(_('Neue Veranstaltung anlegen'));