current code from svn, revision 62608

19 files changed, 1743 insertions, 0 deletions

diff --git a/lib/activities/Activity.php b/lib/activities/Activity.php
new file mode 100644
index 0000000..b8ed662
--- /dev/null
+++ b/lib/activities/Activity.php
@@ -0,0 +1,192 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class Activity extends \SimpleORMap
+{
+    public
+        $object_url,
+        $object_route;
+
+    private $context_object;
+
+    const GC_MAX_DAYS = 366; // Garbage collector removes activities after 366 days
+
+    private static $allowed_verbs = [
+        'answered',
+        'attempted',
+        'attended',
+        'completed',
+        'created',
+        'deleted',
+        'edited',
+        'experienced',
+        'failed',
+        'imported',
+        'interacted',
+        'passed',
+        'shared',
+        'sent',
+        'voided'
+    ];
+
+    /**
+     * {@inheritdoc}
+     */
+    protected static function configure($config = [])
+    {
+        $config['db_table'] = 'activities';
+        $config['additional_fields']['object_url'] = ['get' => 'getUrlList'];
+        $config['additional_fields']['object_route'] = ['get' => 'getRoute'];
+
+        parent::configure($config);
+    }
+
+    /**
+     * return a string representation for this activity
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        return $this->content['content'];
+    }
+
+    /**
+     * set one of the allowed verbs
+     *
+     * @param string $verb
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function setVerb($verb)
+    {
+        if (is_null($verb)) {
+            return;
+        }
+
+        if (in_array($verb, self::$allowed_verbs) === false) {
+            throw new \InvalidArgumentException("That verb is not allowed.");
+        }
+
+        $this->content['verb'] = $verb;
+    }
+
+    /**
+     * Add a url to the list of urls
+     *
+     * @param type $url
+     * @param type $name
+     */
+    public function addUrl($url, $name)
+    {
+        $this->object_url[$url] = $name;
+    }
+
+    /**
+     * Return assoc array of urls
+     * [[url => description]]
+     *
+     * @return Array
+     */
+    public function getUrlList()
+    {
+        return $this->object_url ?: [];
+    }
+
+    /**
+     * Return api route of the content object
+     *
+     * @return string
+     */
+    public function getRoute()
+    {
+        return $this->object_route;
+    }
+
+    public function setContextObject(Context $context)
+    {
+        $this->context_object = $context;
+    }
+
+    public function getContextObject()
+    {
+        return $this->context_object;
+    }
+
+    /**
+     * Returns a format string as placeholder for the object in question
+     * (in a grammatical / lexical sense)
+     *
+     * @return string
+     */
+    public function verbToText()
+    {
+        $translation = [
+            'answered'    => _('beantwortete %s'),
+            'attempted'   => _('versuchte %s'),
+            'attended'    => _('nahm teil an %s'),
+            'completed'   => _('beendete %s'),
+            'created'     => _('erstellte %s'),
+            'deleted'     => _('löschte %s'),
+            'edited'      => _('bearbeitete %s'),
+            'experienced' => _('erlebte %s'),
+            'failed'      => _('verfehlte %s'),
+            'imported'    => _('importierte %s'),
+            'interacted'  => _('interagierte mit %s'),
+            'passed'      => _('bestand %s'),
+            'shared'      => _('teilte %s'),
+            'sent'        => _('sendete %s'),
+            'voided'      => _('löschte %s')
+        ];
+
+        return ($translation[$this->verb]);
+    }
+
+    /**
+     * Garbage collector for the activities.
+     * Removes all activites older than GC_MAX_DAYS (default: 366).
+     */
+    public static function doGarbageCollect()
+    {
+        $stmt = \DBManager::get()->prepare('DELETE FROM activities WHERE mkdate < ?');
+
+        $stmt->execute([
+            time() - self::GC_MAX_DAYS * 24 * 60 * 60]
+        );
+
+        //Expire Cache
+        \StudipCacheFactory::getCache()->expire('activity/oldest_activity');
+    }
+
+    /**
+     * Returns the oldest existing activity
+     *
+     * @return Array
+     */
+    public static function getOldestActivity()
+    {
+        $cache = \StudipCacheFactory::getCache();
+        $cache_key = 'activity/oldest_activity';
+
+        if (!$activity = unserialize($cache->read($cache_key))) {
+            $activity = self::findBySQL('1 ORDER BY mkdate ASC LIMIT 1');
+
+            if (!empty($activity)) {
+                $cache->write($cache_key, serialize($activity));
+            } else {
+                return false;
+            }
+        }
+
+        return $activity;
+    }
+
+
+}
diff --git a/lib/activities/ActivityObserver.php b/lib/activities/ActivityObserver.php
new file mode 100644
index 0000000..80652cf
--- /dev/null
+++ b/lib/activities/ActivityObserver.php
@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @license     GPL 2 or later
+ */
+
+
+namespace Studip\Activity;
+
+class ActivityObserver
+{
+    /**
+     * Register for Notifications the providers shall respond to
+     *
+     */
+    public static function initialize()
+    {
+        \NotificationCenter::addObserver('Studip\Activity\MessageProvider', 'postActivity','MessageDidSend');
+
+        // Notifications for ParticipantsProvider
+        \NotificationCenter::addObserver('\Studip\Activity\ParticipantsProvider', 'postActivity','UserDidEnterCourse');
+        \NotificationCenter::addObserver('\Studip\Activity\ParticipantsProvider', 'postActivity','UserDidLeaveCourse');
+
+        //Notifications for DocumentsProvider
+        \NotificationCenter::addObserver('\Studip\Activity\DocumentsProvider', 'postActivity','FileRefDidCreate');
+        \NotificationCenter::addObserver('\Studip\Activity\DocumentsProvider', 'postActivity','FileRefDidUpdate');
+        \NotificationCenter::addObserver('\Studip\Activity\DocumentsProvider', 'postActivity','FileRefDidDelete');
+
+        //Notifications for NewsProvider
+        \NotificationCenter::addObserver('\Studip\Activity\NewsProvider', 'postActivity','StudipNewsDidCreate');
+
+        //Notifications for WikiProvider
+        \NotificationCenter::addObserver('\Studip\Activity\WikiProvider', 'postActivity','WikiPageDidCreate');
+        \NotificationCenter::addObserver('\Studip\Activity\WikiProvider', 'postActivity','WikiPageDidDelete');
+        //this is rather pointless and annoying
+        //\NotificationCenter::addObserver('\Studip\Activity\WikiProvider', 'postActivity','WikiPageDidUpdate');
+
+        //Notifications for ScheduleProvider (Course)
+        \NotificationCenter::addObserver('\Studip\Activity\ScheduleProvider', 'postActivity','CourseDidChangeSchedule');
+    }
+}
diff --git a/lib/activities/ActivityProvider.php b/lib/activities/ActivityProvider.php
new file mode 100644
index 0000000..16d474a
--- /dev/null
+++ b/lib/activities/ActivityProvider.php
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @license     GPL 2 or later
+ */
+
+
+namespace Studip\Activity;
+
+interface ActivityProvider
+{
+    /**
+     * Fill in the url, route and any lengthy content for the passed activity
+     *
+     * @param Studip\Activity\Activity $activity
+     */
+    public function getActivityDetails($activity);
+
+    /**
+     * Human readable name for the current provider to be used in the activity-title
+     */
+    public static function getLexicalField();
+}
diff --git a/lib/activities/Context.php b/lib/activities/Context.php
new file mode 100644
index 0000000..3f84452
--- /dev/null
+++ b/lib/activities/Context.php
@@ -0,0 +1,124 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+abstract class Context
+{
+    protected
+        $provider,
+        $observer;
+
+
+    /**
+     * return array, listing all active providers in this context
+     *
+     * @return array
+     */
+    abstract protected function getProvider();
+
+    /**
+     * get id denoting the context (user_id, course_id, institute_id, ...)
+     *
+     * @return string
+     */
+    abstract public function getRangeId();
+
+    /**
+     * get type of context (f.e. user, system, course, institute, ...)
+     *
+     * @return string
+     */
+    abstract public function getContextType();
+
+    /**
+     * get type of context (f.e. user, system, course, institute, ...)
+     *
+     * @return string
+     */
+    abstract public function getContextFullname($format = 'default');
+
+    /**
+     * Return user for who wants to watch his and related activities
+     *
+     * @return object  a user object
+     */
+    public function getObserver()
+    {
+        return $this->observer;
+    }
+
+    /**
+     * get list of activities as array for the current context
+     *
+     * @param \Studip\Activity\Filter $filter
+     *
+     * @return array
+     */
+    public function getActivities(Filter $filter)
+    {
+        $providers = $this->filterProvider($this->getProvider(), $filter);
+        $activities = Activity::findAndMapBySQL(
+            function ($activity) use ($providers) {
+                if (isset($providers[$activity->provider])) {                        // provider is available
+                    $activity->setContextObject($this);
+                    if ($providers[$activity->provider]->getActivityDetails($activity)) {
+                        return $activity;
+                    }
+                }
+            },
+            'context = ? AND context_id = ?  AND mkdate >= ? AND mkdate <= ? ORDER BY mkdate DESC'
+            ,
+            [$this->getContextType(), $this->getRangeId(), $filter->getStartDate(), $filter->getEndDate()]);
+        return array_filter($activities);
+    }
+
+    /**
+     * Add a provider to this context
+     *
+     * @param string $provider    the name for the provider
+     * @param string $class_name  the class that belongs to the provider
+     */
+    protected function addProvider($class_name)
+    {
+        $reflectionClass = new \ReflectionClass($class_name);
+        $this->provider[$class_name] =  $reflectionClass->newInstanceArgs();
+    }
+
+    /**
+     * Filter the passed the providers to match the passed filter
+     *
+     * @param type $providers
+     * @param \Studip\Activity\Filter $filter
+     * @return type
+     */
+    protected function filterProvider($providers, Filter $filter)
+    {
+        $filtered_providers = [];
+
+        if (empty($filter->getType())) {
+            $filtered_providers = $providers;
+        } else {
+            foreach ($providers as $provider) {
+                $ctype = $this->getContextType();
+                $filtered_classes = $filter->getType()->$ctype;
+
+                if (is_array($filtered_classes)) {
+                    foreach ($filtered_classes as $class) {
+                        $iclass = 'Studip\\Activity\\' .ucfirst($class) .'Provider';
+                        if ($provider instanceof $iclass) {
+                            $filtered_providers[$iclass] =  $provider;
+                        }
+                    }
+                }
+            }
+        }
+
+        return $filtered_providers;
+    }
+}
diff --git a/lib/activities/CourseContext.php b/lib/activities/CourseContext.php
new file mode 100644
index 0000000..3822847
--- /dev/null
+++ b/lib/activities/CourseContext.php
@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class CourseContext extends Context
+{
+    private
+        $course;
+
+    /**
+     * create new course-context
+     *
+     * @param string $seminar_id
+     */
+    function __construct($course, $observer)
+    {
+        $this->course = $course;
+        $this->observer = $observer;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getProvider()
+    {
+        if (!$this->provider) {
+            $course = $this->course;
+
+            $module_provider = [
+                'CoreForum' => 'ForumProvider',
+                'CoreParticipants' => 'ParticipantsProvider',
+                'CoreDocuments' => 'DocumentsProvider',
+                'CoreWiki' => 'WikiProvider',
+                'CoreSchedule' => 'ScheduleProvider'
+            ];
+
+            foreach ($course->tools as $tool) {
+                $studip_module = $tool->getStudipModule();
+                if($studip_module) {
+                    if (isset($module_provider[get_class($studip_module)])) {
+                        $this->addProvider('Studip\Activity\\'. $module_provider[get_class($studip_module)]);
+                    } elseif ($studip_module instanceof ActivityProvider) {
+                        $this->provider[$studip_module->getPluginName()] = $studip_module;
+                    }
+                }
+            }
+            //news
+            $this->addProvider('Studip\Activity\NewsProvider');
+        }
+
+        return $this->provider;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getRangeId()
+    {
+        return $this->course->id;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContextType()
+    {
+        return \Context::COURSE;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContextFullname($format = 'default')
+    {
+        return $this->course->getFullname($format);
+    }
+}
diff --git a/lib/activities/CoursewareContext.php b/lib/activities/CoursewareContext.php
new file mode 100755
index 0000000..a7bd83b
--- /dev/null
+++ b/lib/activities/CoursewareContext.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace Studip\Activity;
+
+class CoursewareContext extends Context
+{
+
+    public function __construct($courseware, $observer)
+    {
+        $this->courseware = $courseware;
+        $this->observer = $observer;
+
+        $id = explode('_' , $this->courseware->id);
+        $this->context = $id[0];
+        $this->range_id = $id[1];
+    }
+
+    protected function getProvider()
+    {
+        $this->addProvider('Studip\Activity\CoursewareProvider');
+
+        return $this->provider;
+    }
+
+    public function getRangeId()
+    {
+        return $this->range_id;
+    }
+
+    public function getContextType()
+    {
+        if($this->context == 'user') {
+            return \Context::USER;
+        }
+
+        if ($this->content == 'course') {
+            return \Context::COURSE;
+        }
+    }
+
+    public function getContextFullname($format = 'default')
+    {
+        if($this->context == 'user') {
+            $user = \User::find($this->range_id);
+
+            return $user->getFullname($format);
+        }
+
+        if($this->context == 'course') {
+            $course = \Course::find($this->range_id);
+
+            return $course->getFullname($format);
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/lib/activities/CoursewareProvider.php b/lib/activities/CoursewareProvider.php
new file mode 100755
index 0000000..5e5faae
--- /dev/null
+++ b/lib/activities/CoursewareProvider.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Studip\Activity;
+
+
+class CoursewareProvider implements ActivityProvider
+{
+
+    public function getActivityDetails($activity)
+    {
+        $structural_element = \Courseware\StructuralElement::find($activity->object_id);
+        if (!$structural_element) {
+            return false;
+        }
+        $payload = json_decode($structural_element['payload']);
+
+        $activity->content = formatReady($payload['description']);
+
+        if ($activity->context == "course") {
+            $url =  \URLHelper::getURL('dispatch.php/course/courseware/?cid='). $activity->context_id . '#/structural_element/' . $structural_element->id;
+            $activity->object_url = [
+                $url => _('Zur Courseware in der Veranstaltung')
+            ];
+        } elseif ($activity->context == "user") {
+            $url =  \URLHelper::getURL('dispatch.php/contents/my_contents'). '#/structural_element/' . $structural_element->id;
+            $activity->object_url = [
+                $url => _('Zur eigenen Courseware')
+            ];
+        }
+
+        return true;
+    }
+
+    public static function getLexicalField()
+    {
+        return _('eine Courseware-Aktivität');
+    }
+}
\ No newline at end of file
diff --git a/lib/activities/DocumentsProvider.php b/lib/activities/DocumentsProvider.php
new file mode 100644
index 0000000..0a770de
--- /dev/null
+++ b/lib/activities/DocumentsProvider.php
@@ -0,0 +1,131 @@
+<?php
+
+/**
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class DocumentsProvider implements ActivityProvider
+{
+
+    /**
+     * get the details for the passed activity
+     *
+     * @param object $activity the activity to fill with details, passed by reference
+     */
+    public function getActivityDetails($activity)
+    {
+        $activity->content = \htmlReady($activity->content);
+
+        $document = \FileRef::find($activity->object_id);
+
+        // check, if current observer has access to document
+        if (!$document || !$activity->getContextObject() || !$document->folder->getTypedFolder()->isFileDownloadable($document, $activity->getContextObject()->getObserver()->id)) {
+            return false;
+        }
+
+        if ($activity->context == "course") {
+            $url = \URLHelper::getUrl("dispatch.php/course/files/flat?cid={$activity->context_id}");
+            $route = \URLHelper::getURL('api.php/file/' . $activity->object_id, NULL, true);
+
+            $activity->object_url = [
+                $url => _('Zum Dateibereich der Veranstaltung')
+            ];
+        } elseif ($activity->context == "institute") {
+            $url = \URLHelper::getUrl("dispatch.php/institute/files/flat?cid={$activity->context_id}");
+            $route= null;
+
+            $activity->object_url = [
+                $url => _('Zum Dateibereich der Einrichtung')
+            ];
+        }
+
+        $activity->object_route = $route;
+
+        return true;
+    }
+
+    /**
+     * posts an activity for a given notification event
+     *
+     * @param String $event a notification for an activity
+     * @param \FileRef  $document information which a relevant for the activity
+     */
+    public static function postActivity($event, $file_ref)
+    {
+        $user_id = $file_ref->user_id;
+        $file_name = $file_ref->name;
+        $course_id = $file_ref->folder->range_id;
+        $file_id = $file_ref->id;
+
+        $type     = $file_ref->folder->range_type;
+        if ($type == 'course') {
+            $course = \Course::find($course_id);
+        } elseif ($type == 'institute') {
+            $course = \Institute::find($course_id);
+        }
+
+        if (!isset($course)) {
+            return;
+        }
+
+        if (in_array($event, ['FileRefDidCreate'])) {
+            $verb = 'created';
+            if ($type == 'course') {
+                $summary = _('Die Datei %s wurde von %s in der Veranstaltung "%s" hochgeladen.');
+            } else {
+                $summary = _('Die Datei %s wurde von %s in der Einrichtung "%s" hochgeladen.');
+            }
+            $summary = sprintf($summary,$file_name, get_fullname($user_id) ,$course->name);
+            $mkdate = $file_ref->mkdate;
+        } elseif (in_array($event, ['FileRefDidUpdate'])) {
+            $verb = 'edited';
+            if ($type == 'course') {
+                $summary = _('Die Datei %s wurde von %s in der Veranstaltung "%s" aktualisiert.');
+            } else {
+                $summary = _('Die Datei %s wurde von %s in der Einrichtung "%s" aktualisiert.');
+            }
+            $summary = sprintf($summary,$file_name, get_fullname($user_id), $course->name);
+            $mkdate = $file_ref->chdate;
+        } elseif (in_array($event, ['FileRefDidDelete'])) {
+            $verb = 'voided';
+            if ($type == 'course') {
+                $summary = _('Die Datei %s wurde von %s in der Veranstaltung "%s" gelöscht.');
+            } else {
+                $summary = _('Die Datei %s wurde von %s in der Einrichtung "%s" gelöscht.');
+            }
+            $summary = sprintf($summary,$file_name, get_fullname($user_id), $course->name);
+            $mkdate = $file_ref->chdate;
+        } else {
+            return;
+        }
+
+        if (isset($verb)) {
+            $activity = Activity::create(
+                [
+                    'provider'     => __CLASS__,
+                    'context'      => $type,
+                    'context_id'   => $course_id,
+                    'content'      => $summary,
+                    'actor_type'   => 'user',      // who initiated the activity?
+                    'actor_id'     => $user_id,    // id of initiator
+                    'verb'         => $verb,       // the activity type
+                    'object_id'    => $file_id,    // the id of the referenced object
+                    'object_type'  => 'documents', // type of activity object
+                    'mkdate'       =>  $mkdate
+                ]
+            );
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getLexicalField()
+    {
+        return _('eine Datei');
+    }
+}
diff --git a/lib/activities/Filter.php b/lib/activities/Filter.php
new file mode 100644
index 0000000..8e1947e
--- /dev/null
+++ b/lib/activities/Filter.php
@@ -0,0 +1,89 @@
+<?php
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class Filter
+{
+    private
+        $start_date,
+        $end_date,
+        $type,
+        $verb;
+
+    /**
+     *
+     * @param string $start_date
+     */
+    public function setStartDate($start_date)
+    {
+        $this->start_date = $start_date;
+    }
+
+    /**
+     *
+     * @return string
+     */
+    public function getStartDate()
+    {
+        return $this->start_date;
+    }
+
+    /**
+     *
+     * @param string $end_date
+     */
+    public function setEndDate($end_date)
+    {
+        $this->end_date = $end_date;
+    }
+
+    /**
+     *
+     * @return string
+     */
+    public function getEndDate()
+    {
+        return $this->end_date;
+    }
+
+    /**
+     *
+     * @param string $type
+     */
+    public function setType($type)
+    {
+        $this->type = $type;
+    }
+
+    /**
+     *
+     * @return string
+     */
+    public function getType()
+    {
+        return $this->type;
+    }
+
+    /**
+     *
+     * @return string
+     */
+    public function getVerb()
+    {
+        return $this->verb;
+    }
+
+    /**
+     *
+     * @param string $verb
+     */
+    public function setVerb($verb)
+    {
+        $this->verb = $verb;
+    }
+}
diff --git a/lib/activities/ForumProvider.php b/lib/activities/ForumProvider.php
new file mode 100644
index 0000000..49260c3
--- /dev/null
+++ b/lib/activities/ForumProvider.php
@@ -0,0 +1,54 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later3
+ */
+
+
+namespace Studip\Activity;
+
+require_once 'public/plugins_packages/core/Forum/models/ForumEntry.php';
+
+class ForumProvider implements ActivityProvider
+{
+    /**
+     * get the details for the passed activity
+     *
+     * @param object $activity the activity to fill with details, passed by reference
+     */
+    public function getActivityDetails($activity)
+    {
+        $post = \ForumEntry::getEntry($activity->object_id);
+
+        if (!$post) {
+            return false;
+        }
+
+        $activity->content = formatReady($post['content']);
+
+        $url = \PluginEngine::getURL('CoreForum', [], 'index/index/' . $post['topic_id']
+                    .'?cid='. $post['seminar_id'] .'&highlight_topic='. $post['topic_id']
+                    .'#'. $post['topic_id']);
+
+        $route = \URLHelper::getURL('api.php/forum_entry/' . $post['topic_id'], NULL, true);
+
+        $activity->object_url = [
+            $url => _('Zum Forum der Veranstaltung')
+        ];
+
+        $activity->object_route = $route;
+
+        return true;
+    }
+
+    /**
+     *  {@inheritdoc}
+     */
+    public static function getLexicalField()
+    {
+        return _('einen Forenbeitrag');
+    }
+
+}
diff --git a/lib/activities/InstituteContext.php b/lib/activities/InstituteContext.php
new file mode 100644
index 0000000..9b7d5c4
--- /dev/null
+++ b/lib/activities/InstituteContext.php
@@ -0,0 +1,80 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class InstituteContext extends Context
+{
+    private $institute;
+
+    /**
+     * create new institute-context
+     *
+     * @param string $institute_id
+     */
+    public function __construct($institute, $observer)
+    {
+        $this->institute = $institute;
+        $this->observer = $observer;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getProvider()
+    {
+        if (!$this->provider) {
+            $institute = $this->institute;
+
+            $module_provider = [
+                'CoreForum' => 'ForumProvider',
+                'CoreDocuments' => 'DocumentsProvider',
+                'CoreWiki' => 'WikiProvider',
+            ];
+
+            foreach ($institute->tools as $tool) {
+                $studip_module = $tool->getStudipModule();
+                if($studip_module) {
+                    if (isset($module_provider[get_class($studip_module)])) {
+                        $this->addProvider('Studip\Activity\\'. $module_provider[get_class($studip_module)]);
+                    } elseif ($studip_module instanceof ActivityProvider) {
+                        $this->provider[$studip_module->getPluginName()] = $studip_module;
+                    }
+                }
+            }
+            //news
+            $this->addProvider('Studip\Activity\NewsProvider');
+        }
+
+        return $this->provider;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getRangeId()
+    {
+        return $this->institute->id;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContextType()
+    {
+        return \Context::INSTITUTE;
+    }
+
+        /**
+     * {@inheritdoc}
+     */
+    public function getContextFullname($format = 'default')
+    {
+        return $this->institute->getFullname($format);
+    }
+}
diff --git a/lib/activities/MessageProvider.php b/lib/activities/MessageProvider.php
new file mode 100644
index 0000000..9d16831
--- /dev/null
+++ b/lib/activities/MessageProvider.php
@@ -0,0 +1,82 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class MessageProvider implements ActivityProvider
+{
+    /**
+     * get the details for the passed activity
+     *
+     * @param object $activity the acitivty to fill with details, passed by reference
+     */
+    public function getActivityDetails($activity)
+    {
+        $message = \Message::find($activity->object_id);
+
+        if (!$message
+            || !$activity->getContextObject()
+            || !$message->permissionToRead($activity->getContextObject()->getObserver()->id))
+        {
+            return false;
+        }
+
+        $activity->content = formatReady($message->message);
+
+        $url = \URLHelper::getUrl("dispatch.php/messages/read/{$message->id}", ['cid' => null]);
+
+        $route = \URLHelper::getURL('api.php/message/' . $message->id, NULL, true);
+
+        $activity->object_url = [
+            $url => _('Zur Nachricht')
+        ];
+
+        $activity->object_route = $route;
+
+        return true;
+    }
+
+
+    /**
+     * posts an activity for a given notification event
+     *
+     * @param String $event a notification for an activity
+     * @param Array  $info information which a relevant for the activity
+     */
+    public static function postActivity($event, $message_id, $data)
+    {
+        foreach ($data['rec_id'] as $rec_id) {
+
+            // activity for receipent
+            $activity = Activity::create(
+                [
+                    'provider'     => __CLASS__,
+                    'context'      => 'user',
+                    'context_id'   => $rec_id,
+                    'content'      => NULL,
+                    'actor_type'   => 'user',           // who initiated the activity?
+                    'actor_id'     => $data['user_id'], // id of initiator
+                    'verb'         => 'sent',           // the activity type
+                    'object_id'    => $message_id,      // the id of the referenced object
+                    'object_type'  => 'message',        // type of activity object
+                    'mkdate'       => time()
+                ]
+            );
+        }
+
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getLexicalField()
+    {
+        return _('eine Nachricht');
+    }
+
+}
diff --git a/lib/activities/NewsProvider.php b/lib/activities/NewsProvider.php
new file mode 100644
index 0000000..eed7fe7
--- /dev/null
+++ b/lib/activities/NewsProvider.php
@@ -0,0 +1,134 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class NewsProvider implements ActivityProvider
+{
+    private function getUrlForContext($news, $activity)
+    {
+        switch ($activity->context) {
+            case 'course':
+                return [
+                    \URLHelper::getUrl('dispatch.php/course/overview/?cid=' . $activity->context_id . '&contentbox_type=news&contentbox_open=' . $activity->object_id) => _('Ankündigungen in der Veranstaltung')
+                ];
+            break;
+
+            case 'institute':
+                return [
+                    \URLHelper::getUrl('dispatch.php/institute/overview?auswahl=' . $activity->context_id) => _('Ankündigungen in der Einrichtung')
+                ];
+            break;
+
+            case 'system':
+                return [
+                    \URLHelper::getUrl('dispatch.php/start?contentbox_type=news&contentbox_open='. $news->getId() .'#'. $news->getId()) => _('Ankündigungen auf der Startseite')
+                ];
+            break;
+
+            case 'user':
+                return [
+                    \URLHelper::getUrl('dispatch.php/profile/?username='. get_username($activity->context_id)
+                        . '&contentbox_type=news&contentbox_open='. $news->getId() .'#'. $news->getId()) => _('Ankündigungen auf der Profilseite')
+                ];
+            break;
+        }
+    }
+
+    /**
+     * posts an activity for a given notification event
+     *
+     * @param String $event a notification for an activity
+     * @param String  $news
+     */
+    public static function postActivity($event, $news)
+    {
+        // delete any old activities for this id
+        $activities = Activity::findBySql('object_id = ?', [$news->id]);
+
+        foreach ($activities as $activity) {
+            $activity->delete();
+        }
+
+        $mkdate = time();
+
+        // iterate over every news-range and create approbriate activity
+        foreach ($news->news_ranges as $range) {
+            $context_id = $range->range_id;
+
+            switch ($range->type) {
+                case 'user':
+                    $context = 'user';
+                    break;
+                case 'inst':
+                case 'fak':
+                    $context = 'institute';
+                    break;
+                case 'sem':
+                    $context = 'course';
+                    break;
+                case 'global':
+                    $context = 'system';
+                    $context_id = 'system';
+                    break;
+            }
+            if (isset($context)) {
+                $activity = Activity::create(
+                    [
+                        'provider'    => __CLASS__,
+                        'context'     => $context,
+                        'context_id'  => $context_id,
+                        'content'     => null,
+                        'actor_type'  => 'user',         // who initiated the activity?
+                        'actor_id'    => $news->user_id, // id of initiator
+                        'verb'        => 'created',      // the activity type
+                        'object_id'   => $news->id,      // the id of the referenced object
+                        'object_type' => 'news',         // type of activity object
+                        'mkdate'      => $mkdate
+                    ]
+                );
+            }
+
+        }
+    }
+
+
+    /**
+     * get the details for the passed activity
+     *
+     * @param object $activity the activity to fill with details, passed by reference
+     */
+    public function getActivityDetails($activity)
+    {
+        $news = new \StudipNews($activity->object_id);
+
+        // do not show unpublished news
+        if ($news->date > time()) {
+            return false;
+        }
+
+        $activity->content = '<b>' . htmlReady((string) $news->topic)
+            .'</b><br>'. formatReady((string) $news->body);
+
+        $url = self::getUrlForContext($news, $activity);
+        $route = \URLHelper::getURL('api.php/news/' . $news->id, NULL, true);
+
+        $activity->object_url = $url;
+        $activity->object_route = $route;
+
+        return true;
+    }
+    /**
+     * {@inheritdoc}
+     */
+    public static function getLexicalField()
+    {
+        return _('eine Ankündigung');
+    }
+
+}
diff --git a/lib/activities/ParticipantsProvider.php b/lib/activities/ParticipantsProvider.php
new file mode 100644
index 0000000..50bad46
--- /dev/null
+++ b/lib/activities/ParticipantsProvider.php
@@ -0,0 +1,84 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class ParticipantsProvider implements ActivityProvider
+{
+
+    /**
+     * posts an activity for a given notification event
+     *
+     * @param String $event a notification for an activity
+     * @param String  $course_id
+     * @param String  $user_id
+     */
+    public static function postActivity($event, $course_id, $user_id)
+    {
+        $course = \Course::find($course_id);
+
+        if ($event == 'UserDidEnterCourse') {
+            $verb = 'created';
+            $summary = _('%s wurde in die Veranstaltung "%s" eingetragen.');
+            $summary = sprintf($summary, get_fullname($user_id), $course->name);
+        } elseif ($event == 'UserDidLeaveCourse') {
+            $verb = 'voided';
+            $summary = _('%s wurde aus der Veranstaltung "%s" ausgetragen.');
+            $summary = sprintf($summary, get_fullname($user_id), $course->name);
+        }
+
+        $type = get_object_type($course_id);
+
+        $activity = Activity::create(
+            [
+                'provider'     => __CLASS__,
+                'context'      => ($type == 'sem') ? 'course' : 'institute',
+                'context_id'   => $course_id,
+                'content'      => $summary,
+                'actor_type'   => 'user',               // who initiated the activity?
+                'actor_id'     => $GLOBALS['user']->id, // id of initiator
+                'verb'         => $verb,                // the activity type
+                'object_id'    => $course_id,           // the id of the referenced object
+                'object_type'  => 'participants',       // type of activity object
+                'mkdate'       =>  time(),
+            ]
+        );
+
+    }
+
+    /**
+     * get the details for the passed activity
+     *
+     * @param object $activity the activity to fill with details, passed by reference
+     */
+    public function getActivityDetails($activity)
+    {
+        $activity->content = htmlReady($activity->content);
+
+        $url = \URLHelper::getUrl("dispatch.php/course/members/index", ['cid' => $activity->context_id]);
+
+        $route = \URLHelper::getURL('api.php/course/' . $activity->context_id, NULL, true);
+
+        $activity->object_url = [
+            $url => _('Zur Veranstaltung')
+        ];
+
+        $activity->object_route = $route;
+
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getLexicalField()
+    {
+        return _('eine/n Teilnehmer/in');
+    }
+
+}
diff --git a/lib/activities/ScheduleProvider.php b/lib/activities/ScheduleProvider.php
new file mode 100644
index 0000000..208b9b3
--- /dev/null
+++ b/lib/activities/ScheduleProvider.php
@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class ScheduleProvider implements ActivityProvider
+{
+    /**
+     * get the details for the passed activity
+     *
+     * @param object $activity the activity to fill with details, passed by reference
+     */
+    public function getActivityDetails($activity)
+    {
+        $activity->content = htmlReady($activity->content);
+
+        $url = \URLHelper::getUrl("dispatch.php/course/dates?cid={$activity->context_id}");
+        $route = \URLHelper::getURL('api.php/course/' . $activity->context_id . '/events', NULL, true);
+
+        $activity->object_url = [
+            $url => _('Zum Ablaufplan der Veranstaltung')
+        ];
+
+        $activity->object_route = $route;
+
+        return true;
+    }
+
+    /**
+     * posts an activity for a given notification event
+     *
+     * @param String $event a notification for an activity
+     * @param Array  $sem Seminar-class for the notification
+     */
+    public static function postActivity($event, $sem)
+    {
+        $range_id = $sem->getId();
+
+        $type = get_object_type($range_id);
+        if ($type == 'sem') {
+            $course = \Course::find($range_id);
+        }
+
+        $user_id = $GLOBALS['user']->id;
+        $mkdate = time();
+
+        if ($event == 'CourseDidChangeSchedule') {
+            $verb = 'edited';
+            $summary = _('Der Ablaufplan wurde in der Veranstaltung "%s" von %s aktualisiert.');
+            $summary = sprintf($summary, $course->name, get_fullname($user_id));
+        }
+
+        $activity = Activity::create(
+            [
+                'provider'     => __CLASS__,
+                'context'      => ($type == 'sem') ? 'course' : 'institute',
+                'context_id'   => $range_id,
+                'content'      => $summary,
+                'actor_type'   => 'user',     // who initiated the activity?
+                'actor_id'     => $user_id,   // id of initiator
+                'verb'         => $verb,      // the activity type
+                'object_id'    => $range_id,  // the id of the referenced object
+                'object_type'  => 'schedule', // type of activity object
+                'mkdate'       =>  $mkdate
+            ]
+        );
+
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getLexicalField()
+    {
+        return _('einen Eintrag im Ablaufplan');
+    }
+
+}
diff --git a/lib/activities/Stream.php b/lib/activities/Stream.php
new file mode 100644
index 0000000..27daf76
--- /dev/null
+++ b/lib/activities/Stream.php
@@ -0,0 +1,190 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class Stream implements \ArrayAccess, \Countable, \IteratorAggregate
+{
+    private $activities;
+
+    /**
+     * creates a stream representing the activities for the passed contexts,
+     * filter by time (if any)
+     *
+     * @param array $contexts All contexts that need to be considered
+     * @param \Studip\Activity\Filter $filter
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function __construct($contexts, Filter $filter)
+    {
+        if (!is_array($contexts)) {
+            $contexts = [$contexts];
+        }
+
+        foreach ($contexts as $context) {
+            if (!$context instanceof Context) {
+                throw new \InvalidArgumentException();
+            }
+        }
+
+        if (!$filter instanceof Filter) {
+            throw new \InvalidArgumentException();
+        }
+
+        //fetch avaible contextes in given timespan
+        $available_contexts = \DBManager::get()->fetchGroupedPairs(
+            "SELECT DISTINCT context,context_id FROM activities WHERE mkdate BETWEEN ? AND ?",
+            [$filter->getStartDate(), $filter->getEndDate()]);
+
+        //fetch activities only for contextes with known activities
+        $activities = array_flatten(array_values(array_filter(array_map(
+            function ($context) use ($filter, $available_contexts) {
+                if (isset($available_contexts[$context->getContextType()])
+                    && in_array($context->getRangeId(), $available_contexts[$context->getContextType()])) {
+                        return $context->getActivities($filter);
+                }
+            }, $contexts))
+        ));
+
+        $new_activities = [];
+
+        foreach ($activities as $activity) {
+            // generate an id for the activity, considering some basic object parameters
+            $id = md5($activity->provider . $activity->content .
+                    $activity->verb . $activity->object_type . $activity->mkdate);
+
+            if ($new_activities[$id]) {
+                $url = key($activity->object_url);
+                $name = current($activity->object_url);
+                next($activity->object_url);
+                $new_activities[$id]->addUrl($url, $name);
+            } else {
+                $new_activities[$id] = $activity;
+            }
+        }
+
+        // sort activites by their mkdate
+        usort($new_activities, function($a, $b) {
+            return $b->mkdate - $a->mkdate;
+        });
+
+        $this->activities = $new_activities;
+    }
+
+    /**
+     * ArrayAccess: Check whether the given offset exists.
+     */
+    public function offsetExists($offset)
+    {
+        return isset($this->activities[$offset]);
+    }
+
+    /**
+     * ArrayAccess: Get the value at the given offset.
+     */
+    public function offsetGet($offset)
+    {
+        return $this->activities[$offset];
+    }
+
+    /**
+     * ArrayAccess: Set the value at the given offset.
+     */
+    public function offsetSet($offset, $value)
+    {
+        $this->activities[$offset] = $value;
+    }
+
+    /**
+     * ArrayAccess: unset the value at the given offset (not applicable)
+     */
+    public function offsetUnset($offset)
+    {
+        unset($this->activities[$offset]);
+    }
+
+    /**
+     * IteratorAggregate
+     */
+    public function getIterator()
+    {
+        return new \ArrayIterator($this->activities);
+    }
+
+    /**
+     * Countable
+     */
+    public function count()
+    {
+        return sizeof($this->activities);
+    }
+
+    /**
+     * return representation of the current stream as an array
+     *
+     * @return array
+     */
+    public function toArray()
+    {
+        $activities = [];
+
+        foreach ($this as $key => $activity) {
+            $activities[$key] = $activity->toArray();
+
+            // add i18n auto generated title prefix
+            $title = '';
+
+            // $class       = '\\Studip\\Activity\\' . ucfirst($activity->provider) . 'Provider';
+            $class       = $activity->provider;
+            $object_text = $class::getLexicalField();
+
+            if (in_array($activity->actor_id, ['____%system%____', 'system']) !== false) {
+                $actor = _('Stud.IP');
+            } elseif ($activity->actor_type === 'anonymous') {
+                $actor = _('Anonym');
+            } else {
+                $actor = get_fullname($activity->actor_id);
+            }
+            $context_name = $activity->getContextObject()->getContextFullname();
+
+            switch ($activity->context) {
+                case 'course':
+                    $title = $actor .' '
+                        . sprintf($activity->verbToText(),
+                            $object_text . sprintf(_(' im Kurs "%s"'), $context_name)
+                        );
+                break;
+
+                case 'institute':
+                    $title = $actor .' '
+                        . sprintf($activity->verbToText(),
+                            $object_text . sprintf(_(' in der Einrichtung "%s"'), $context_name)
+                        );
+                break;
+
+                case 'system':
+                    $title = $actor .' '
+                        . sprintf($activity->verbToText(), _('allen')) .' '
+                        . $object_text;
+                break;
+
+                case 'user':
+                    $title = $actor .' '
+                        . sprintf($activity->verbToText(), $context_name) .' '
+                        . $object_text;
+                break;
+
+            }
+
+            $activities[$key]['title'] = $title;
+        }
+
+        return $activities;
+    }
+}
diff --git a/lib/activities/SystemContext.php b/lib/activities/SystemContext.php
new file mode 100644
index 0000000..ddc5872
--- /dev/null
+++ b/lib/activities/SystemContext.php
@@ -0,0 +1,56 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class SystemContext extends Context
+{
+    /**
+     * create new user-context
+     *
+     * @param string $user_id
+     */
+    public function __construct($observer)
+    {
+        $this->observer = $observer;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getProvider()
+    {
+        $this->addProvider('Studip\Activity\NewsProvider');
+
+        return $this->provider;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getRangeId()
+    {
+        return 'system';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContextType()
+    {
+        return 'system';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getContextFullname($format = 'default')
+    {
+        return _('Stud.IP');
+    }
+}
diff --git a/lib/activities/UserContext.php b/lib/activities/UserContext.php
new file mode 100644
index 0000000..0ff8921
--- /dev/null
+++ b/lib/activities/UserContext.php
@@ -0,0 +1,74 @@
+<?php
+
+/**
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @author      Till Glöggler <gloeggler@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class UserContext extends Context
+{
+    private $user;
+
+    /**
+     * create new user-context
+     *
+     * @param string $user_id
+     */
+    public function __construct($user, $observer)
+    {
+        $this->user = $user;
+        $this->observer = $observer;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getRangeId()
+    {
+        return $this->user->id;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getProvider()
+    {
+
+        if (!$this->provider) {
+            $this->addProvider('Studip\Activity\NewsProvider');
+
+            if ($this->user->id === $this->observer->id) {
+                $this->addProvider('Studip\Activity\MessageProvider');
+            }
+
+            foreach (\PluginManager::getInstance()->getPlugins(ActivityProvider::class) as $plugin) {
+                if ($plugin instanceof \HomepagePlugin
+                    && $plugin->isActivated($this->user->id, 'user')
+                ) {
+                    $this->provider[] = $plugin;
+                }
+            }
+        }
+
+        return $this->provider;
+    }
+
+    /**
+    * {@inheritdoc}
+    */
+    public function getContextType()
+    {
+        return \Context::USER;
+    }
+
+    /**
+    * {@inheritdoc}
+    */
+    public function getContextFullname($format = 'default')
+    {
+        return $this->user->getFullname($format);
+    }
+}
diff --git a/lib/activities/WikiProvider.php b/lib/activities/WikiProvider.php
new file mode 100644
index 0000000..e412279
--- /dev/null
+++ b/lib/activities/WikiProvider.php
@@ -0,0 +1,125 @@
+<?php
+
+/**
+ * @author      Till Glöggler <tgloeggl@uos.de>
+ * @author      André Klaßen <klassen@elan-ev.de>
+ * @license     GPL 2 or later
+ */
+
+namespace Studip\Activity;
+
+class WikiProvider implements ActivityProvider
+{
+    /**
+     * get the details for the passed activity
+     *
+     * @param object $activity the activity to fill with details, passed by reference
+     */
+    public function getActivityDetails($activity)
+    {
+        // Check visibility of wiki page
+        $page = \WikiPage::findLatestPage($activity->context_id, $activity->object_id);
+        if ($page && !$page->isVisibleTo($GLOBALS['user'])) {
+            return false;
+        }
+
+        $activity->content = \htmlReady($activity->content);
+
+        if ($activity->context === 'course') {
+            $url = \URLHelper::getURL('wiki.php', ['cid' => $activity->context_id, 'keyword' => $activity->object_id]);
+            $route = \URLHelper::getURL("api.php/course/{$activity->context_id}/wiki/{$activity->object_id}", null, true);
+
+            $activity->object_url = [
+                $url => _('Zum Wiki der Veranstaltung'),
+            ];
+
+            $activity->object_route = $route;
+
+        } elseif ($activity->context === 'institute') {
+            $url = \URLHelper::getURL('wiki.php', ['cid' => $activity->context_id, 'keyword' => $activity->object_id]);
+            $route= null;
+
+            $activity->object_url = [
+                $url => _('Zum Wiki der Einrichtung')
+            ];
+
+            $activity->object_route = $route;
+        }
+
+        return true;
+    }
+
+    /**
+     * posts an activity for a given notification event
+     *
+     * @param String $event a notification for an activity
+     * @param \WikiPage  $info information which a relevant for the activity
+     */
+    public static function postActivity($event, $info)
+    {
+        $range_id = $info['range_id'];
+        $keyword = $info['keyword'];
+
+        $type = get_object_type($range_id);
+        if ($type === 'sem') {
+            $course = \Course::find($range_id);
+        } else {
+            $course = \Institute::find($range_id);
+        }
+
+        $user_id = $GLOBALS['user']->id;
+        $mkdate = time();
+
+
+        if ($event === 'WikiPageDidCreate' && $info['version'] > 1) {
+            $event = 'WikiPageDidUpdate';
+        }
+
+        if ($event === 'WikiPageDidCreate') {
+            $verb = 'created';
+            if ($type === 'sem') {
+                $summary = _('Die Wiki-Seite %s wurde von %s in der Veranstaltung "%s" angelegt.');
+            } else {
+                $summary = _('Die Wiki-Seite %s wurde von %s in der Einrichtung "%s" angelegt.');
+            }
+        } elseif ($event === 'WikiPageDidUpdate') {
+            $verb = 'edited';
+            if ($type === 'sem') {
+                $summary = _('Die Wiki-Seite %s wurde von %s in der Veranstaltung "%s" aktualisiert.');
+            } else {
+                $summary = _('Die Wiki-Seite %s wurde von %s in der Einrichtung "%s" aktualisiert.');
+            }
+        } elseif ($event === 'WikiPageDidDelete') {
+            $verb = 'voided';
+            if ($type === 'sem') {
+                $summary = _('Die Wiki-Seite %s wurde von %s in der Veranstaltung "%s" gelöscht.');
+            } else {
+                $summary = _('Die Wiki-Seite %s wurde von %s in der Einrichtung "%s" gelöscht.');
+            }
+        }
+
+        $summary = sprintf($summary, $keyword, get_fullname($user_id), $course->name);
+
+        $activity = Activity::create([
+            'provider'     => __CLASS__,
+            'context'      => $type === 'sem' ? 'course' : 'institute',
+            'context_id'   => $range_id,
+            'content'      => $summary,
+            'actor_type'   => 'user',   // who initiated the activity?
+            'actor_id'     => $user_id, // id of initiator
+            'verb'         => $verb,    // the activity type
+            'object_id'    => $keyword, // the id of the referenced object
+            'object_type'  => 'wiki',   // type of activity object
+            'mkdate'       =>  $mkdate,
+        ]);
+
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getLexicalField()
+    {
+        return _('eine Wiki-Seite');
+    }
+}