Resolve "Forum 3"

Closes #5146

Merge request studip/studip!3845

17 files changed, 948 insertions, 1113 deletions

diff --git a/app/controllers/admin/user.php b/app/controllers/admin/user.php
index 88b5272..5a0cd9d 100644
--- a/app/controllers/admin/user.php
+++ b/app/controllers/admin/user.php
@@ -1517,15 +1517,11 @@ class Admin_UserController extends AuthenticatedController
             'details' => "files",
         ];
 
-        foreach (PluginEngine::getPlugins(ForumModule::class) as $plugin) {
-            $table     = $plugin->getEntryTableInfo();
-            $queries[] = [
-                'desc'  => $plugin->getPluginName() . ' - ' . _("Anzahl der Postings"),
-                'query' => 'SELECT COUNT(*) FROM `' . $table['table'] . '`
-            WHERE `' . $table['user_id'] . '` = ?
-            GROUP BY `' . $table['user_id'] . '`',
-            ];
-        }
+        // Forum
+        $queries[] = [
+            'desc'    => _('Forum - Anzahl der Postings'),
+            'query'   => "SELECT COUNT(*) FROM `forum_postings` WHERE `user_id` = ? GROUP BY `user_id`"
+        ];
 
         // Evaluate queries
         foreach ($queries as $index => $query) {
diff --git a/app/controllers/course/forum/ForumBaseController.php b/app/controllers/course/forum/ForumBaseController.php
new file mode 100644
index 0000000..cefa5a4
--- /dev/null
+++ b/app/controllers/course/forum/ForumBaseController.php
@@ -0,0 +1,66 @@
+<?php
+namespace Forum;
+
+use ActionsWidget;
+use Context;
+use CoreForum;
+use Icon;
+use Request;
+use SearchWidget;
+use Sidebar;
+use StudipController;
+
+abstract class ForumBaseController extends StudipController
+{
+    protected $with_session = true;
+
+    public function before_filter(&$action, &$args)
+    {
+        object_set_visit_module('forum');
+
+        $this->course_id = Context::getId();
+        $this->is_moderator = CoreForum::isModerator($this->course_id);
+        $this->is_admin = CoreForum::isAdmin($this->course_id);
+
+        $this->buildSidebar();
+
+        parent::before_filter($action, $args);
+    }
+
+    protected function buildSidebar(): void
+    {
+        $actions = new ActionsWidget();
+
+        if ($this->is_moderator) {
+            $actions->addLink(
+                _('Neue Diskussion starten'),
+                $this->url_for('course/forum/discussions/edit'),
+                Icon::create('add', Icon::ROLE_CLICKABLE, ['title' => _('Neue Diskussion starten')])
+            )->asDialog('width=900;height=750');
+        }
+
+        if ($this->is_admin) {
+            $actions->addLink(
+                _('Forum verwalten'),
+                $this->url_for('course/forum/configs/edit'),
+                Icon::create('admin', Icon::ROLE_CLICKABLE, ['title' => _('Forum verwalten')]),
+                ['data-dialog' => 'width=500;height=300']
+            );
+        }
+
+        Sidebar::Get()->addWidget($actions);
+
+        $search = new SearchWidget($this->url_for('course/forum/search', [
+            'begin' => Request::int('begin'),
+            'end' => Request::int('end')
+        ]));
+
+        $search->addNeedle(
+            _('Suche nach Diskussionen oder Beiträge'),
+            'keyword',
+            true
+        );
+
+        Sidebar::Get()->addWidget($search, 'forum_search');
+    }
+}
diff --git a/app/controllers/course/forum/admin.php b/app/controllers/course/forum/admin.php
deleted file mode 100644
index e4d21d8..0000000
--- a/app/controllers/course/forum/admin.php
+++ /dev/null
@@ -1,133 +0,0 @@
-<?php
-
-/*
- * Copyright (C) 2011 - Till Glöggler     <tgloeggl@uos.de>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- */
-
-require_once 'forum_controller.php';
-
-class Course_Forum_AdminController extends ForumController
-{
-    /* * * * * * * * * * * * * * * * * * * * */
-    /* * *   A D M I N   M E T H O D S   * * */
-    /* * * * * * * * * * * * * * * * * * * * */
-
-    /**
-     * show the administration page for mass-editing forum-entries
-     */
-    function index_action()
-    {
-        ForumPerm::check('admin', $this->getId());
-        $nav = Navigation::getItem('course/forum2');
-        $nav->setImage(Icon::create('forum', 'info'));
-        Navigation::activateItem('course/forum2/admin');
-
-        $list = ForumEntry::getList('flat', $this->getId());
-
-        // sort by cat
-        $new_list = [];
-        $this->categories = [];
-        // iterate over all categories and add the belonging areas to them
-        $categories = ForumCat::getListWithAreas($this->getId(), false) ;
-        foreach ($categories as $category) {
-            if (!empty($category['topic_id'])) {
-                $new_list[$category['category_id']][$category['topic_id']] = $list['list'][$category['topic_id']];
-                unset($list['list'][$category['topic_id']]);
-            } else if (ForumPerm::has('add_area', $this->seminar_id)) {
-                $new_list[$category['category_id']] = [];
-            }
-            $this->categories[$category['category_id']] = $category['entry_name'];
-        }
-
-        if (!empty($list['list'])) {
-            // append the remaining entries to the standard category
-            $new_list[$this->getId()] = array_merge((array)$new_list[$this->getId()], $list['list']);
-        }
-
-        $this->list = $new_list;
-
-    }
-
-    /**
-     * show child entries for the passed entry
-     *
-     * @param string $parent_id id of entry to get the childs for
-     */
-    function childs_action($parent_id)
-    {
-        $this->set_layout(null);
-
-        // if the parent-id is a category-id, get all areas for this category
-        if ($cat = ForumCat::get($parent_id)) {
-            ForumPerm::check('admin', $cat['seminar_id']);  // check the perms in the categories seminar
-            $this->entries = ForumEntry::parseEntries(ForumCat::getAreas($parent_id));
-        } else {
-            ForumPerm::check('admin', $this->getId(), $parent_id);
-            $entries = ForumEntry::getList('flat', $parent_id);
-            $this->entries = $entries['list'];
-        }
-    }
-
-    /**
-     * move the submitted topics[] to the passed destination
-     *
-     * @param string $destination id of seminar to move topics to
-     */
-    function move_action($destination)
-    {
-        // check if destination is a category_id. if yes, use seminar_id instead
-        if (ForumCat::get($destination)) {
-            $category_id = $destination;
-            $destination = $this->getId();
-        } else {
-            $category_id = null;
-        }
-
-        ForumPerm::check('admin', $this->getId(), $destination);
-
-        foreach (Request::getArray('topics') as $topic_id) {
-            // make sure every passed topic_id is checked against the current seminar
-            ForumPerm::check('admin', $this->getId(), $topic_id);
-
-            // if the source is an area and the target a category, just move this area to the category
-            $entry = ForumEntry::getEntry($topic_id);
-            if ($entry['depth'] == 1 && $category_id) {
-                ForumCat::removeArea($topic_id);
-                ForumCat::addArea($category_id, $topic_id);
-            } else {
-                // first step: move the whole topic with all childs
-                ForumEntry::move($topic_id, $destination);
-
-                // if the current topic id is an area, remove it from any categories
-                ForumCat::removeArea($topic_id);
-
-                // second step: move all to deep childs a level up (depth > 3)
-                $data = ForumEntry::getList('depth_to_large', $topic_id);
-
-                if (!empty($data['list'])) {
-                    foreach ($data['list'] as $entry) {
-                        $path = ForumEntry::getPathToPosting($entry['topic_id']);
-                        array_shift($path); // Category
-                        array_shift($path); // Area
-
-                        $thread = array_shift($path); // Thread
-
-                        ForumEntry::move($entry['topic_id'], $thread['id']);
-                    }
-                }
-
-                // add entry to passed category when moving to the top
-                if ($category_id) {
-                    ForumCat::addArea($category_id, $topic_id);
-                }
-            }
-        }
-
-        $this->render_nothing();
-    }
-}
diff --git a/app/controllers/course/forum/area.php b/app/controllers/course/forum/area.php
deleted file mode 100644
index 821129f..0000000
--- a/app/controllers/course/forum/area.php
+++ /dev/null
@@ -1,79 +0,0 @@
-<?php
-
-/*
- * Copyright (C) 2011 - Till Glöggler     <tgloeggl@uos.de>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- */
-
-require_once 'forum_controller.php';
-
-class Course_Forum_AreaController extends ForumController
-{
-    function add_action($category_id)
-    {
-        ForumPerm::check('add_area', $this->getId());
-
-        $new_id = md5(uniqid(rand()));
-
-        $name    = Request::get('name', _('Kein Titel'));
-        $content = Request::get('content');
-
-        ForumEntry::insert([
-            'topic_id'    => $new_id,
-            'seminar_id'  => $this->getId(),
-            'user_id'     => $GLOBALS['user']->id,
-            'name'        => $name,
-            'content'     => $content,
-            'author'      => get_fullname($GLOBALS['user']->id),
-            'author_host' => ($GLOBALS['user']->id == 'nobody') ? getenv('REMOTE_ADDR') : ''
-        ], $this->getId());
-
-        ForumCat::addArea($category_id, $new_id);
-
-        if (Request::isXhr()) {
-            $this->set_layout(null);
-            $entries = ForumEntry::parseEntries([ForumEntry::getEntry($new_id)]);
-            $this->entry = array_pop($entries);
-            $this->visitdate = ForumVisit::getLastVisit($this->getId());
-        } else {
-            $this->redirect('course/forum/index/index/');
-        }
-    }
-
-    function edit_action($area_id)
-    {
-        ForumPerm::check('edit_area', $this->getId(), $area_id);
-
-        ForumEntry::update($area_id, Request::get('name'), Request::get('content'));
-        if (Request::isAjax()) {
-            $this->render_json(['content' => ForumEntry::killFormat(ForumEntry::killEdit(Request::get('content')))]);
-        } else {
-            $this->flash['messages'] = ['success' => _('Die Änderungen am Bereich wurden gespeichert.')];
-            $this->redirect('course/forum/index/index');
-        }
-
-    }
-
-    function save_order_action()
-    {
-        ForumPerm::check('sort_area', $this->getId());
-
-        foreach (Request::getArray('areas') as $category_id => $areas) {
-            $pos = 0;
-            foreach ($areas as $area_id) {
-                ForumPerm::checkCategoryId($this->getId(), $category_id);
-                ForumPerm::check('sort_area', $this->getId(), $area_id);
-
-                ForumCat::addArea($category_id, $area_id);
-                ForumCat::setAreaPosition($area_id, $pos);
-                $pos++;
-            }
-        }
-
-        $this->render_nothing();
-    }
-}
diff --git a/app/controllers/course/forum/categories.php b/app/controllers/course/forum/categories.php
new file mode 100644
index 0000000..2ff5dc6
--- /dev/null
+++ b/app/controllers/course/forum/categories.php
@@ -0,0 +1,122 @@
+<?php
+require_once 'ForumBaseController.php';
+
+use Forum\ForumCategory;
+
+class Course_Forum_CategoriesController extends Forum\ForumBaseController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        if (!CourseConfig::get($this->course_id)->FORUM_HIDE_CATEGORIES_NAVIGATION) {
+            Navigation::activateItem('course/forum/categories');
+        } else {
+            Navigation::activateItem('course/forum/topics');
+        }
+    }
+
+    public function index_action()
+    {
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/categories/Index')
+        );
+    }
+
+    public function show_action($category_id)
+    {
+        $category = ForumCategory::find($category_id);
+
+        if (!$category) {
+            throw new AccessDeniedException();
+        }
+
+        PageLayout::setTitle($category->name);
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/categories/Show')
+                ->withProps([
+                    'category' => $category->transformData(),
+                    'metadata' => [
+                        'postings_count' => (int) $category->metadata['postings_count'],
+                        'users_count' => (int) $category->metadata['users_count'],
+                        'recent_activity' => date('c', $category->metadata['recent_activity'])
+                    ]
+            ])
+        );
+    }
+
+    public function edit_action($category_id = null)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        if ($category_id) {
+            PageLayout::setTitle(_('Kategorie bearbeiten'));
+            $category = ForumCategory::findOneBySQL("range_id = ? AND category_id = ?", [$this->course_id, $category_id]);
+
+            if (!$category) {
+                throw new AccessDeniedException();
+            }
+        } else {
+            PageLayout::setTitle(_('Neue Kategorie anlegen'));
+            $category = new ForumCategory();
+        }
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/categories/Edit')
+                ->withProps([
+                    'category' => $category->transformData()
+                ])
+        );
+    }
+
+    public function save_action($category_id = null)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        CSRFProtection::verifyUnsafeRequest();
+
+        if ($category_id) {
+            $category = ForumCategory::findOneBySQL("range_id = ? AND category_id = ?", [$this->course_id, $category_id]);
+            if (!$category) {
+                throw new AccessDeniedException();
+            }
+        } else {
+            $category = new ForumCategory();
+            $category->range_id = $this->course_id;
+        }
+
+        $category->name = Request::get('name');
+        $category->description = Request::get('description');
+        $category->color = Request::get('color');
+
+        $category->store();
+
+        PageLayout::postSuccess(sprintf(_('Die Kategorie „%s“ wurde gespeichert.'), $category->name));
+
+        $this->relocate('course/forum/categories');
+    }
+
+    public function delete_action($category_id)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        $category = ForumCategory::findOneBySQL("range_id = ? AND category_id = ?", [$this->course_id, $category_id]);
+
+        if (!$category) {
+            throw new AccessDeniedException();
+        }
+
+        $category->delete();
+
+        PageLayout::postSuccess(_('Die Kategorie wurde gelöscht.'));
+
+        $this->relocate('course/forum/categories');
+    }
+}
diff --git a/app/controllers/course/forum/configs.php b/app/controllers/course/forum/configs.php
new file mode 100644
index 0000000..70fdb2b
--- /dev/null
+++ b/app/controllers/course/forum/configs.php
@@ -0,0 +1,34 @@
+<?php
+require_once 'ForumBaseController.php';
+
+class Course_Forum_ConfigsController extends Forum\ForumBaseController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        if (! $this->is_admin) {
+            throw new AccessDeniedException();
+        }
+    }
+
+    public function edit_action()
+    {
+        $this->config = Context::get()->getConfiguration();
+    }
+
+    public function save_action()
+    {
+        CSRFProtection::verifyUnsafeRequest();
+
+        $this->config = Context::get()->getConfiguration();
+
+        $this->config->store('FORUM_MODERATION_PERMISSION', trim(Request::option('forum_moderation_permission')));
+
+        $this->config->store('FORUM_HIDE_CATEGORIES_NAVIGATION', Request::bool('forum_hide_categories_navigation'));
+
+        PageLayout::postSuccess(_('Die Einstellungen wurden gespeichert.'));
+
+        $this->relocate('course/forum/topics');
+    }
+}
diff --git a/app/controllers/course/forum/discussion_types.php b/app/controllers/course/forum/discussion_types.php
new file mode 100644
index 0000000..da4ea27
--- /dev/null
+++ b/app/controllers/course/forum/discussion_types.php
@@ -0,0 +1,83 @@
+<?php
+use Forum\ForumDiscussionType;
+
+class Course_Forum_DiscussionTypesController extends AuthenticatedController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        PageLayout::setTitle(_('Forum Diskussions-Typ'));
+
+        $GLOBALS['perm']->check('root');
+
+        Navigation::activateItem('/admin/locations/forum_discussion_types');
+
+        $actions = new ActionsWidget();
+
+        $actions->addLink(
+            _('Neuen Diskussionstyp anlegen'),
+            $this->url_for('course/forum/discussion_types/edit'),
+            Icon::create('add', Icon::ROLE_CLICKABLE, ['title' => _('Neuen Diskussionstyp anlegen')])
+        )->asDialog('width=700');
+
+        Sidebar::Get()->addWidget($actions);
+    }
+
+    public function index_action()
+    {
+        $this->discussion_types = ForumDiscussionType::findBySQL("TRUE ORDER BY mkdate DESC");
+    }
+
+    public function edit_action(ForumDiscussionType $discussion_type = null)
+    {
+        if ($discussion_type->isNew()) {
+            PageLayout::setTitle(_('Neuen Diskussionstyp anlegen'));
+        } else {
+            PageLayout::setTitle(_('Diskussionstyp bearbeiten'));
+        }
+
+        $icons = [];
+
+        foreach (scandir($GLOBALS['STUDIP_BASE_PATH'] . '/public/assets/images/icons/blue') as $icon_path) {
+            if (!is_dir(
+                    $GLOBALS['STUDIP_BASE_PATH'] . '/public/assets/images/icons/blue/'
+                ) . $icon_path && $icon_path[0] !== '.') {
+                if (stripos($icon_path, '.svg')) {
+                    $icon_path = substr($icon_path, 0, stripos($icon_path, '.svg'));
+                }
+                $icons[] = $icon_path;
+            }
+        }
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/discussions_types/Edit')->withProps([
+                'icons' => array_unique($icons),
+                'discussion_type' => $discussion_type->toRawArray()
+            ])
+        );
+    }
+
+    public function save_action(ForumDiscussionType $discussion_type = null)
+    {
+        CSRFProtection::verifyUnsafeRequest();
+
+        $discussion_type->name = Request::get('name');
+        $discussion_type->icon = Request::get('icon');
+
+        $discussion_type->store();
+
+        PageLayout::postSuccess(sprintf(_('Der Diskussionstyp „%s“ wurde gespeichert.'), $discussion_type->name));
+
+        $this->relocate('course/forum/discussion_types/index');
+    }
+
+    public function delete_action(ForumDiscussionType $discussion_type)
+    {
+        $discussion_type->delete();
+
+        PageLayout::postSuccess(_('Der Diskussionstyp wurde gelöscht.'));
+
+        $this->relocate('course/forum/discussion_types/index');
+    }
+}
diff --git a/app/controllers/course/forum/discussions.php b/app/controllers/course/forum/discussions.php
new file mode 100644
index 0000000..745c370
--- /dev/null
+++ b/app/controllers/course/forum/discussions.php
@@ -0,0 +1,220 @@
+<?php
+require_once 'ForumBaseController.php';
+
+use Studip\Markup;
+use Forum\ForumDiscussion;
+use Forum\ForumDiscussionType;
+use Forum\DTO\ForumMember;
+use Forum\ForumPosting;
+use Forum\ForumPostingRead;
+use Forum\ForumSubscription;
+use Forum\DTO\ForumTag;
+use Forum\ForumTopic;
+
+class Course_Forum_DiscussionsController extends Forum\ForumBaseController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        Navigation::activateItem('course/forum/topics');
+    }
+
+    public function show_action($discussion_id)
+    {
+        $discussion = ForumDiscussion::find($discussion_id);
+
+        if (!$discussion) {
+            throw new AccessDeniedException();
+        }
+
+        PageLayout::setTitle($discussion->title);
+
+        $auth_user = User::findCurrent();
+
+        $discussion->view_count += 1;
+        $discussion->store();
+
+        $posting_read = ForumPostingRead::findOneBySQL(
+            "discussion_id = :discussion_id AND user_id = :user_id",
+            [
+                'discussion_id' => $discussion->getId(),
+                'user_id' => User::findCurrent()->user_id
+            ]
+        );
+
+        $user_subscription = ForumSubscription::findOneBySQL(
+            "subject = :subject AND subject_id = :subject_id AND user_id = :user_id",
+            [
+                'subject' => 'discussion',
+                'subject_id' => $discussion->getId(),
+                'user_id' => $auth_user->user_id
+            ]
+        );
+
+        $category = $discussion->getCategory();
+        $tags = array_map(fn(ForumTag $tag) => $tag->toRawArray(), $discussion->tags);
+        $members = array_map(fn(ForumMember $member) => $member->toRawArray(), $discussion->members);
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/discussions/Show')
+                ->withProps([
+                    'auth_user' => [
+                        'id' => $auth_user->id,
+                        'username' => $auth_user->username,
+                        'name' => $auth_user->getFullName(),
+                        'avatar_url' => Avatar::getAvatar($auth_user->user_id)->getURL(Avatar::NORMAL),
+                        'subscription' => $user_subscription ? $user_subscription->toRawArray() : []
+                    ],
+                    'discussion' => [
+                        ...$discussion->transformData(),
+                        'topic' => $discussion->topic->toRawArray(),
+                        'tags' => $tags,
+                        'members' => $members,
+                        'type' => !empty($discussion->discussion_type) ? $discussion->discussion_type->toRawArray() : []
+                    ],
+                    'category' => $category ? $category->toRawArray() : [],
+                    'read_index' => (int) ($posting_read ? $posting_read->read_index : 0),
+                    'redirect' => Request::option('redirect'),
+                    'search_keyword' => $_SESSION['forum'][$this->course_id]['search']['keyword'] ?? ''
+                ])
+        );
+    }
+
+    public function edit_action(ForumDiscussion $discussion = null)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        if ($discussion->isNew()) {
+            PageLayout::setTitle(_('Neue Diskussion starten'));
+        } else {
+            PageLayout::setTitle(_('Diskussion bearbeiten'));
+        }
+
+        $topics = DBManager::get()->fetchAll(
+            "
+                SELECT
+                    `ft`.`topic_id`, `ft`.`name`, `fc`.`color`
+                FROM `forum_topics` AS `ft`
+                LEFT JOIN `forum_categories` AS `fc` USING (`category_id`)
+                WHERE `ft`.`range_id` = :course_id
+                ORDER BY `ft`.`position` ASC, `ft`.`mkdate` DESC
+            ",
+            ['course_id' => $this->course_id]
+        );
+
+        $all_tags = array_map(fn(ForumTag $tag) => $tag->toRawArray(), ForumTag::getForumTags());
+        $discussion_tags = array_map(fn(ForumTag $tag) => $tag->toRawArray(), $discussion->tags);
+        $discussion_types = array_map(fn(ForumDiscussionType $discussion_type) => $discussion_type->toRawArray(), ForumDiscussionType::getForumDiscussionType());
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/discussions/Edit')
+                ->withProps([
+                    'discussion' => [
+                        ...$discussion->transformData(),
+                        'topic_id' => !empty($discussion->topic_id) ? $discussion->topic_id : Request::option('topic_id'),
+                        'tags' => $discussion_tags
+                    ],
+                    'topics' => $topics,
+                    'tags' => $all_tags,
+                    'discussion_types' => $discussion_types
+                ])
+        );
+    }
+
+    public function save_action($discussion_id = null)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        CSRFProtection::verifyUnsafeRequest();
+
+        if ($discussion_id) {
+            $discussion = ForumDiscussion::find($discussion_id);
+        } else {
+            $discussion = new ForumDiscussion();
+        }
+
+        $discussion->title = Request::get('title');
+        $discussion->closed_at = Request::bool('closed_at', false) ? time() : null;
+        $discussion->sticky = Request::bool('sticky', false);
+
+        if (Request::get('type_id')) {
+            $discussion->type_id = Request::get('type_id');
+        }
+
+        $topic = json_decode(Request::get('topic'), true);
+
+        if (empty($topic['topic_id'])) {
+            $newTopic = ForumTopic::create([
+                'range_id' => $this->course_id,
+                'name' => $topic['name']
+            ]);
+
+            $topic['topic_id'] = $newTopic->topic_id;
+        }
+
+        $discussion->topic_id = $topic['topic_id'];
+        $discussion->store();
+
+        if (!$discussion_id && Request::get('content')) {
+            ForumPosting::create([
+                'range_id' => $this->course_id,
+                'discussion_id' => $discussion->discussion_id,
+                'content' => Markup::markAsHtml(Request::get('content')),
+                'user_id' => User::findCurrent()->user_id
+            ]);
+        } else {
+            TagRelation::deleteBySQL("range_id = ? AND range_type = 'forum'", [$discussion->discussion_id]);
+        }
+
+        $tags = json_decode(Request::get('tags'), true);
+
+        foreach ($tags as $tag) {
+            if (empty($tag['tag_id'])) {
+                $newTag = Tag::create([
+                    'name' => $tag['name'],
+                ]);
+
+                $tag['tag_id'] = $newTag->id;
+            }
+
+            TagRelation::create([
+                'tag_id' => $tag['tag_id'],
+                'range_id' => $discussion->discussion_id,
+                'range_type' => 'forum'
+            ]);
+        }
+
+        PageLayout::postSuccess(_('Der Beitrag wurde gespeichert.'));
+
+        $this->relocate(
+            $discussion_id ? 'course/forum/topics/show/' . $discussion->topic_id : 'course/forum/discussions/show/' . $discussion->discussion_id
+        );
+    }
+
+    public function delete_action($discussion_id)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        $discussion = ForumDiscussion::find($discussion_id);
+
+        if (!$discussion) {
+            throw new AccessDeniedException();
+        }
+
+        TagRelation::deleteBySQL("range_id = ? AND range_type = 'forum'", [$discussion->discussion_id]);
+        $topic_id = $discussion->topic_id;
+
+        $discussion->delete();
+
+        PageLayout::postSuccess(_('Die Diskussion wurde gelöscht.'));
+
+        $this->relocate('course/forum/topics/show/' . $topic_id);
+    }
+}
diff --git a/app/controllers/course/forum/forum_controller.php b/app/controllers/course/forum/forum_controller.php
deleted file mode 100644
index 65eec63..0000000
--- a/app/controllers/course/forum/forum_controller.php
+++ /dev/null
@@ -1,51 +0,0 @@
-<?php
-
-abstract class ForumController extends StudipController {
-    protected $with_session = true;
-
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-    /* * * * * H E L P E R   F U N C T I O N S * * * * */
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-    function getId()
-    {
-        return ForumHelpers::getSeminarId();
-    }
-
-    /**
-     * Common code for all actions: set default layout and page title.
-     *
-     * @param type $action
-     * @param type $args
-     */
-    function before_filter(&$action, &$args)
-    {
-        $this->validate_args($args, ['option', 'option']);
-
-        parent::before_filter($action, $args);
-
-        $this->flash = Trails\Flash::instance();
-
-        // Set help keyword for Stud.IP's user-documentation and page title
-        PageLayout::setHelpKeyword('Basis.Forum');
-        PageLayout::setTitle(Context::getHeaderLine() .' - '. _('Forum'));
-
-        // the default for displaying timestamps
-        $this->time_format_string = "%a %d. %B %Y, %H:%M";
-        $this->time_format_string_short = "%d.%m.%Y, %H:%M";
-
-        //$this->getId() depends on Context::get()
-        checkObject();
-        ForumVisit::setVisit($this->getId());
-        if (Request::int('page')) {
-            ForumHelpers::setPage(Request::int('page'));
-        }
-
-        $this->seminar_id = $this->getId();
-
-        $this->no_entries = false;
-        $this->highlight = [];
-        $this->highlight_topic = '';
-        $this->edit_posting = '';
-        $this->js = '';
-    }
-}
diff --git a/app/controllers/course/forum/index.php b/app/controllers/course/forum/index.php
deleted file mode 100644
index a4f6fb1..0000000
--- a/app/controllers/course/forum/index.php
+++ /dev/null
@@ -1,829 +0,0 @@
-<?php
-
-/*
- * Copyright (C) 2011 - Till Glöggler     <tgloeggl@uos.de>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- */
-
-require_once 'forum_controller.php';
-
-class Course_Forum_IndexController extends ForumController
-{
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-    /*  V   I   E   W   -   A   C   T   I   O   N   S  */
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-
-    /**
-     * redirect to correct page (overview or newest entries),
-     * depending on whether there are any entries.
-     */
-    function enter_seminar_action() {
-        if (ForumPerm::has('fav_entry', $this->getId())
-            && ForumVisit::getCount($this->getId(), ForumVisit::getVisit($this->getId())) > 0) {
-            $this->redirect('course/forum/index/newest');
-        } else {
-            $this->redirect('course/forum/index/index');
-        }
-    }
-
-    /**
-     * the main action for the forum. May be called with a topic_id to be displayed
-     * and optionally the page to display
-     *
-     * @param type $topic_id the topic to display, defaults to the main
-     *                       view of the current seminar
-     * @param type $page the page to be displayed (for thread-view)
-     */
-    function index_action($topic_id = null, $page = null)
-    {
-        $nav = Navigation::getItem('course/forum2');
-        $nav->setImage(Icon::create('forum', 'info'));
-        Navigation::activateItem('course/forum2/index');
-
-        // check, if the root entry is present
-        ForumEntry::checkRootEntry($this->getId());
-
-        /* * * * * * * * * * * * * * * * * * *
-         * V A R I A B L E N   F U E L L E N *
-         * * * * * * * * * * * * * * * * * * */
-
-        $this->section   = 'index';
-
-        $this->topic_id   = $topic_id ? $topic_id : $this->getId();
-        $this->constraint = ForumEntry::getConstraints($this->topic_id);
-
-        // check if there has been submitted an invalid id and use seminar_id in case
-        if (!$this->constraint) {
-            $this->topic_id   = $this->getId();
-            $this->constraint = ForumEntry::getConstraints($this->topic_id);
-        }
-
-        $this->highlight_topic = Request::option('highlight_topic', null);
-
-        // set page to which we shall jump
-        if ($page) {
-            ForumHelpers::setPage($page);
-        }
-
-        // we do not crawl deeper than level 2, we show a page chooser instead
-        if ($this->constraint['depth'] > 2) {
-            ForumHelpers::setPage(ForumEntry::getPostingPage($this->topic_id, $this->constraint));
-
-            $path               = ForumEntry::getPathToPosting($this->topic_id);
-            array_shift($path);array_shift($path);$path_element = array_shift($path);
-            $this->child_topic  = $this->topic_id;
-            $this->topic_id     = $path_element['id'];
-            $this->constraint   = ForumEntry::getConstraints($this->topic_id);
-        }
-
-        // check if the topic_id matches the currently selected seminar
-        ForumPerm::checkTopicId($this->getId(), $this->topic_id);
-
-
-        /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
-         * B E R E I C H E / T H R E A D S / P O S T I N G S   L A D E N *
-         * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
-
-        // load list of areas for use in thread-movement
-        if (ForumPerm::has('move_thread', $this->getId())) {
-            $this->areas = ForumEntry::getList('flat', $this->getId());
-        }
-
-        if ($this->constraint['depth'] > 1) {   // POSTINGS
-            $list = ForumEntry::getList('postings', $this->topic_id);
-            if (!empty($list['list'])) {
-                $this->postings          = $list['list'];
-                $this->number_of_entries = $list['count'];
-            }
-        } else {
-            if ($this->constraint['depth'] == 0) {  // BEREICHE
-                $list = ForumEntry::getList('area', $this->topic_id);
-            } else {
-                $list = ForumEntry::getList('list', $this->topic_id);
-            }
-
-            if ($this->constraint['depth'] == 0) {  // BEREICHE
-                $new_list = [];
-                $this->categories  = [];
-                // iterate over all categories and add the belonging areas to them
-                foreach (ForumCat::getListWithAreas($this->getId(), false) as $category) {
-                    if ($category['topic_id']) {
-                        $new_list[$category['category_id']][$category['topic_id']] = $list['list'][$category['topic_id']];
-                        unset($list['list'][$category['topic_id']]);
-                    } else if (ForumPerm::has('add_area', $this->seminar_id)) {
-                        $new_list[$category['category_id']] = [];
-                    }
-                    $this->categories[$category['category_id']] = $category['entry_name'];
-                }
-
-                if (!empty($list['list'])) {
-                    // append the remaining entries to the standard category
-                    if (!isset($new_list[$this->getId()])) {
-                        $new_list[$this->getId()] = [];
-                    }
-                    $new_list[$this->getId()] = array_merge((array)$new_list[$this->getId()], $list['list']);
-                }
-
-                // check, if there are any orphaned entries
-                foreach ($new_list as $key1 => $list_item) {
-                    foreach ($list_item as $key2 => $contents) {
-                        if (empty($contents)) {
-                            // remove the orphaned entry from the list and from the database
-                            unset($new_list[$key1][$key2]);
-                            ForumCat::removeArea($key2);
-                        }
-                    }
-                }
-
-                $this->list = $new_list;
-
-            } else if ($this->constraint['depth'] == 1) {   // THREADS
-                if (!empty($list['list'])) {
-                    $this->list = [$list['list']];
-                }
-            }
-            $this->number_of_entries = $list['count'];
-        }
-
-        // set the visit-date and get the stored last_visitdate
-        $this->visitdate = ForumVisit::getLastVisit($this->getId());
-
-        $this->seminar_id = $this->getId();
-
-        // highlight text if passed some words to highlight
-        if (Request::getArray('highlight')) {
-            $this->highlight = Request::optionArray('highlight');
-        }
-
-        if (($this->edit_posting = Request::get('edit_posting', null))
-                && !ForumPerm::hasEditPerms($this->edit_posting)) {
-            $this->edit_posting = null;
-        }
-
-        // trigger a javascript action, like creating an answer or citing a thread
-        if (Request::submitted('answer')) {
-            $this->js = 'answer';
-        } else if (Request::option('cite')) {
-            $this->js = 'cite';
-            $this->cite_id = $topic_id;
-        }
-
-    }
-
-    /**
-     * show newest entries
-     *
-     * @param int $page show entries on submitted page
-     */
-    function newest_action($page = null)
-    {
-        ForumPerm::check('fav_entry', $this->getId());
-
-        $nav = Navigation::getItem('course/forum2');
-        $nav->setImage(Icon::create('forum', 'info'));
-        Navigation::activateItem('course/forum2/newest');
-
-        // set page to which we shall jump
-        if ($page) {
-            ForumHelpers::setPage($page);
-        }
-
-        $this->section = 'newest';
-        $this->topic_id = $this->getId();
-
-        // set the visitdate of the seminar as the last visitdate
-        $this->visitdate = ForumVisit::getLastVisit($this->getId());
-
-        $list = ForumEntry::getList('newest', $this->topic_id);
-        $this->postings          = $list['list'] ?? [];
-        $this->number_of_entries = $list['count'] ?? 0;
-        $this->show_full_path    = true;
-
-        if (empty($this->postings)) {
-            $this->no_entries = true;
-        }
-
-        $this->render_action('index');
-    }
-
-    /**
-     * show all latest entries as flat list
-     *
-     * @param int $page show entries on submitted page
-     */
-    function latest_action($page = null)
-    {
-        ForumPerm::check('fav_entry', $this->getId());
-
-        $nav = Navigation::getItem('course/forum2');
-        $nav->setImage(Icon::create('forum', 'info'));
-        Navigation::activateItem('course/forum2/latest');
-
-        // set page to which we shall jump
-        if ($page) {
-            ForumHelpers::setPage($page);
-        }
-
-        $this->section = 'latest';
-        $this->topic_id = $this->getId();
-
-        // set the visitdate of the seminar as the last visitdate
-        $this->visitdate = ForumVisit::getLastVisit($this->getId());
-
-        $list = ForumEntry::getList('latest', $this->topic_id);
-        $this->postings          = $list['list'];
-        $this->number_of_entries = $list['count'];
-        $this->show_full_path    = true;
-        $this->no_entries        = empty($this->postings);
-
-        $this->render_action('index');
-    }
-
-    /**
-     * show the current users favorized entries
-     *
-     * @param int $page show entries on submitted page
-     */
-    function favorites_action($page = null)
-    {
-        ForumPerm::check('fav_entry', $this->getId());
-
-        $nav = Navigation::getItem('course/forum2');
-        $nav->setImage(Icon::create('forum', 'info'));
-        Navigation::activateItem('course/forum2/favorites');
-
-        // set page to which we shall jump
-        if ($page) {
-            ForumHelpers::setPage($page);
-        }
-
-        $this->section = 'favorites';
-        $this->topic_id = $this->getId();
-
-        $list = ForumEntry::getList('favorites', $this->topic_id);
-        $this->postings          = $list['list'];
-        $this->number_of_entries = $list['count'];
-        $this->show_full_path    = true;
-        $this->no_entries        = empty($this->postings);
-
-        // exploit the visitdate for this view
-        $this->visitdate = ForumVisit::getLastVisit($this->getId());
-
-        $this->render_action('index');
-    }
-
-    /**
-     * show search results
-     *
-     * @param int $page show entries on submitted page
-     */
-    function search_action($page = null)
-    {
-        if (Request::submitted('reset-search')) {
-            $this->redirect('course/forum/index/index');
-            return;
-        }
-
-        ForumPerm::check('search', $this->getId());
-
-        $nav = Navigation::getItem('course/forum2');
-        $nav->setImage(Icon::create('forum', 'info'));
-        Navigation::activateItem('course/forum2/index');
-
-        // set page to which we shall jump
-        if ($page) {
-            ForumHelpers::setPage($page);
-        }
-
-        $this->section = 'search';
-        $this->topic_id = $this->getId();
-        $this->show_full_path = true;
-        $this->options = [];
-        // parse filter-options
-        foreach (['search_title', 'search_content', 'search_author'] as $option) {
-            $this->options[$option] = Request::option($option);
-        }
-
-        $this->searchfor = Request::get('searchfor');
-        if (mb_strlen($this->searchfor) < 3) {
-            $this->flash['messages'] = ['error' => _('Ihr Suchbegriff muss mindestens 3 Zeichen lang sein und darf nur Buchstaben und Zahlen enthalten!')];
-        } else {
-            // get search-results
-            $list = ForumEntry::getSearchResults($this->getId(), $this->searchfor, $this->options);
-
-            $this->postings          = $list['list'];
-            $this->number_of_entries = $list['count'] ?? 0;
-            $this->highlight         = $list['highlight'] ?? false;
-
-            if (empty($this->postings)) {
-                $this->flash['messages'] = ['info' => _('Es wurden keine Beiträge gefunden, die zu Ihren Suchkriterien passen!')];
-            }
-        }
-
-        // exploit the visitdate for this view
-        $this->visitdate = ForumVisit::getLastVisit($this->getId());
-
-        $this->render_action('index');
-    }
-
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-    /* * * *   P O S T I N G - A C T I O N S     * * * */
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-
-    /**
-     * Add a new entry. Has a simple spambot protection and checks
-     * the parent_id to add the entry to, throwing an exception if missing.
-     *
-     * @throws Exception
-     */
-    function add_entry_action()
-    {
-        CSRFProtection::verifyUnsafeRequest();
-        // Schutz vor Spambots - diese füllen meistens alle Felder aus, auch "versteckte".
-        // Ist dieses Feld gefüllt, war das vermutlich kein Mensch
-        if (Request::get('nixda')) {
-            throw new Exception('Access denied!');
-        }
-
-        if (!$parent_id = Request::option('parent')) {
-            throw new Exception('missing seminar_id/topic_id while adding a new entry!');
-        }
-
-        if ($this->seminar_id == $parent_id) {
-            ForumPerm::check('add_area', $this->getId(), $parent_id);
-        } else {
-            ForumPerm::check('add_entry', $this->getId(), $parent_id);
-        }
-
-        $constraints = ForumEntry::getConstraints($parent_id);
-
-        // if we are answering/citing a posting, we want to add it to the thread
-        // (which is the parent of passed posting id)
-        if ($constraints['depth'] == 3) {
-            $parent_id = ForumEntry::getParentTopicId($parent_id);
-        }
-
-        $new_id = md5(uniqid(rand()));
-
-        if ($GLOBALS['user']->id == 'nobody') {
-            $fullname = Request::get('author', 'unbekannt');
-        } else {
-            $fullname = get_fullname($GLOBALS['user']->id);
-        }
-
-        ForumEntry::insert([
-            'topic_id'    => $new_id,
-            'seminar_id'  => $this->getId(),
-            'user_id'     => $GLOBALS['user']->id,
-            'name'        => Request::get('name') ?: '',
-            'content'     => Studip\Markup::purifyHtml(Request::get('content')),
-            'author'      => $fullname,
-            'author_host' => ($GLOBALS['user']->id == 'nobody') ? getenv('REMOTE_ADDR') : '',
-            'anonymous'   => Config::get()->FORUM_ANONYMOUS_POSTINGS ? Request::get('anonymous') ? : 0 : 0
-        ], $parent_id);
-
-        $this->flash['notify'] = $new_id;
-
-        $this->redirect('course/forum/index/index/' . $new_id .'#'. $new_id);
-    }
-
-    /**
-     * Delete the submitted entry.
-     *
-     * @param string $topic_id the entry to delete
-     */
-    function delete_entry_action($topic_id)
-    {
-        // get the page of the posting to be able to jump there again
-        $page = ForumEntry::getPostingPage($topic_id);
-        URLHelper::addLinkParam('page', $page);
-        $parent = null;
-        if (
-            ForumPerm::hasEditPerms($topic_id)
-            || ForumPerm::check('remove_entry', $this->getId(), $topic_id)
-        ) {
-            CSRFProtection::verifyUnsafeRequest();
-            $path = ForumEntry::getPathToPosting($topic_id);
-            $topic  = array_pop($path);
-            $parent = array_pop($path);
-
-            if ($topic_id != $this->getId()) {
-                ForumEntry::delete($topic_id);
-                PageLayout::postSuccess(sprintf(_('Der Eintrag %s wurde gelöscht!'), htmlReady($topic['name'])));
-            } else {
-                PageLayout::postWarning(_('Sie können nicht die gesamte Veranstaltung löschen!'));
-            }
-        }
-
-        $this->redirect('course/forum/index/index/' . $parent['id'] .'/'. $page);
-    }
-
-    /**
-     * Update the submitted entry.
-     *
-     * @param string $topic_id id of the entry to update
-     * @throws AccessDeniedException
-     */
-    function update_entry_action($topic_id)
-    {
-        CSRFProtection::verifyUnsafeRequest();
-
-        $name    = Request::get('name', _('Kein Titel'));
-        $content = Studip\Markup::purifyHtml(Request::get('content', _('Keine Beschreibung')));
-
-        ForumPerm::check('add_entry', $this->getId(), $topic_id);
-
-        if (ForumPerm::hasEditPerms($topic_id)) {
-            ForumEntry::update($topic_id, $name, $content);
-        } else {
-            throw new AccessDeniedException(_('Sie haben keine Berechtigung, diesen Eintrag zu editieren!'));
-        }
-
-        if (Request::isXhr()) {
-            $this->render_text(json_encode([
-                'name'    => htmlReady($name),
-                'content' => formatReady($content)
-            ]));
-        } else {
-            $this->redirect('course/forum/index/index/' . $topic_id .'#'. $topic_id);
-        }
-    }
-
-    /**
-     * Move the submitted thread to the submitted parent
-     *
-     * @param string $thread_id    the thread to move
-     * @param string $destination  the threads new parent
-     */
-    function move_thread_action($thread_id, $destination) {
-        ForumPerm::check('move_thread', $this->getId(), $thread_id);
-        ForumPerm::check('move_thread', $this->getId(), $destination);
-
-        $current_area = ForumEntry::getParentTopicId($thread_id);
-
-        ForumEntry::move($thread_id, $destination);
-
-        $this->redirect('course/forum/index/index/' . $current_area .'/'. ForumHelpers::getPage());
-    }
-
-    /**
-     * Mark the submitted entry as favorite
-     *
-     * @param string $topic_id the entry to mark
-     */
-    function set_favorite_action($topic_id)
-    {
-        ForumPerm::check('fav_entry', $this->getId(), $topic_id);
-
-        ForumFavorite::set($topic_id);
-
-        if (Request::isXhr()) {
-            $this->topic_id = $topic_id;
-            $this->favorite = true;
-            $this->render_template('course/forum/index/_favorite');
-        } else {
-            $this->redirect('course/forum/index/index/' . $topic_id .'#'. $topic_id);
-        }
-    }
-
-    /**
-     * Remove the submtted entry as favorite
-     *
-     * @param string $topic_id the entry to unmark
-     */
-    function unset_favorite_action($topic_id) {
-        ForumPerm::check('fav_entry', $this->getId(), $topic_id);
-
-        ForumFavorite::remove($topic_id);
-
-        if (Request::isXhr()) {
-            $this->topic_id = $topic_id;
-            $this->favorite = false;
-            $this->render_template('course/forum/index/_favorite');
-        } else {
-            $this->redirect('course/forum/index/index/' . $topic_id .'#'. $topic_id);
-        }
-    }
-
-    /**
-     * Jump to page in the entries of the submitted parent-entry
-     * denoted by the submitted context (section)
-     *
-     * @param string $topic_id  the parent-topic to goto
-     * @param string $section   the type of view (one of index/search)
-     * @param int $page         the page to jump to
-     */
-    function goto_page_action($topic_id, $section, $page)
-    {
-        switch ($section) {
-            case 'index':
-                $this->redirect('course/forum/index/index/' . $topic_id .'/'. (int)$page .'#'. $topic_id);
-                break;
-
-            case 'search':
-                $optionlist = [];
-
-                foreach (['search_title', 'search_content', 'search_author'] as $option) {
-                    if (Request::option($option)) {
-                        $optionlist[] = $option .'='. 1;
-                    }
-                }
-
-                $this->redirect('course/forum/index/'. $section .'/'. (int)$page
-                    .'/?searchfor='. Request::get('searchfor') .'&'. implode('&', $optionlist));
-                break;
-
-            default:
-                $this->redirect('course/forum/index/'. $section .'/'. (int)$page);
-                break;
-        }
-    }
-
-    /**
-     * Like the submitted topic
-     *
-     * @param string $topic_id the topic to like
-     */
-    function like_action($topic_id)
-    {
-        if (!Request::isPost()) {
-            throw new MethodNotAllowedException();
-        }
-
-        ForumPerm::check('like_entry', $this->getId(), $topic_id);
-
-        ForumLike::like($topic_id);
-
-        if (Request::isXhr()) {
-            $this->topic_id   = $topic_id;
-            $this->render_template('course/forum/index/_like');
-        } else {
-            $this->redirect('course/forum/index/index/' . $topic_id .'#'. $topic_id);
-        }
-    }
-
-    /**
-     * Remove like for the submitted topic
-     *
-     * @param string $topic_id the topic to unlike
-     */
-    function dislike_action($topic_id)
-    {
-        if (!Request::isPost()) {
-            throw new MethodNotAllowedException();
-        }
-
-        ForumPerm::check('like_entry', $this->getId(), $topic_id);
-
-        ForumLike::dislike($topic_id);
-
-        if (Request::isXhr()) {
-            $this->topic_id   = $topic_id;
-            $this->render_template('course/forum/index/_like');
-        } else {
-            $this->redirect('course/forum/index/index/' . $topic_id .'#'. $topic_id);
-        }
-    }
-
-    /**
-     * This action is used to close a thread.
-     *
-     * @param string $topic_id the topic which will be closed
-     * @param string $redirect the topic which will be shown after closing the thread
-     * @param int    $page the page number of the topic $redirect
-     */
-    function close_thread_action($topic_id, $redirect, $page = 0)
-    {
-        ForumPerm::check('close_thread', $this->getId(), $topic_id);
-
-        ForumEntry::close($topic_id);
-
-        $success_text = _('Das Thema wurde erfolgreich geschlossen.');
-
-        if (Request::isXhr()) {
-            $this->render_text(MessageBox::success($success_text));
-        } else {
-            PageLayout::postSuccess($success_text);
-            $this->redirect('course/forum/index/index/' . $redirect . '/' . $page);
-        }
-    }
-
-    /**
-     * This action is used to open a thread.
-     *
-     * @param string $topic_id the topic which will be opened
-     * @param string $redirect the topic which will be shown after opening the thread
-     * @param int    $page the page number of the topic $redirect
-     */
-    function open_thread_action($topic_id, $redirect, $page = 0)
-    {
-        ForumPerm::check('close_thread', $this->getId(), $topic_id);
-
-        ForumEntry::open($topic_id);
-
-        $success_text = _('Das Thema wurde erfolgreich geöffnet.');
-
-        if (Request::isXhr()) {
-            $this->render_text(MessageBox::success($success_text));
-        } else {
-            PageLayout::postSuccess($success_text);
-            $this->redirect('course/forum/index/index/' . $redirect . '/' . $page);
-        }
-    }
-
-    /**
-     * This action is used to mark a thread as sticky.
-     *
-     * @param string $topic_id the topic which will be marked as sticky.
-     * @param string $redirect the topic which will be shown afterwards
-     * @param int    $page the page number of the topic $redirect
-     */
-    function make_sticky_action($topic_id, $redirect, $page = 0)
-    {
-        ForumPerm::check('make_sticky', $this->getId(), $topic_id);
-
-        ForumEntry::sticky($topic_id);
-
-        $success_text = _('Das Thema wurde erfolgreich in der Themenliste hervorgehoben.');
-
-        if (Request::isXhr()) {
-            $this->render_text(MessageBox::success($success_text));
-        } else {
-            $this->flash['messages'] = ['success' => $success_text];
-            $this->redirect('course/forum/index/index/' . $redirect . '/' . $page);
-        }
-    }
-
-    /**
-     * This action is used to remove the sticky attribute from a topic.
-     *
-     * @param string $topic_id the topic which will be marked as unsticky.
-     * @param string $redirect the topic which will be shown afterwards
-     * @param int    $page the page number of the topic $redirect
-     */
-    function make_unsticky_action($topic_id, $redirect, $page = 0)
-    {
-        ForumPerm::check('make_sticky', $this->getId(), $topic_id);
-
-        ForumEntry::unsticky($topic_id);
-
-        $success_text = _('Die Hervorhebung des Themas in der Themenliste wurde entfernt.');
-
-        if (Request::isXhr()) {
-            $this->render_text(MessageBox::success($success_text));
-        } else {
-            $this->flash['messages'] = ['success' => $success_text];
-            $this->redirect('course/forum/index/index/' . $redirect . '/' . $page);
-        }
-    }
-
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-    /* * * *     C O N F I G - A C T I O N S     * * * */
-    /* * * * * * * * * * * * * * * * * * * * * * * * * */
-
-    /**
-     * Add submitted category to current course
-     */
-    function add_category_action()
-    {
-        CSRFProtection::verifyUnsafeRequest();
-
-        ForumPerm::check('add_category', $this->getId());
-
-        $category_id = ForumCat::add($this->getId(), Request::get('category'));
-
-        ForumPerm::checkCategoryId($this->getId(), $category_id);
-
-        $this->redirect('course/forum/index#cat_'. $category_id);
-    }
-
-    /*
-     * Remove submitted category from current course
-     */
-    function remove_category_action($category_id)
-    {
-        CSRFProtection::verifyUnsafeRequest();
-
-        ForumPerm::checkCategoryId($this->getId(), $category_id);
-        ForumPerm::check('remove_category', $this->getId());
-
-        $this->flash['messages'] = ['success' => _('Die Kategorie wurde gelöscht!')];
-        ForumCat::remove($category_id, $this->getId());
-
-        if (Request::isXhr()) {
-            $this->render_template('course/forum/messages');
-        } else {
-            $this->redirect('course/forum/index/index');
-        }
-
-    }
-
-    /**
-     * Change the name of the submitted category
-     *
-     * @param string $category_id the category to edit
-     */
-    function edit_category_action($category_id) {
-        CSRFProtection::verifyUnsafeRequest();
-
-        ForumPerm::checkCategoryId($this->getId(), $category_id);
-        ForumPerm::check('edit_category', $this->getId());
-
-        if (Request::isXhr()) {
-            ForumCat::setName($category_id, Request::get('name'));
-            $this->render_nothing();
-        } else {
-            ForumCat::setName($category_id, Request::get('name'));
-            $this->flash['messages'] = ['success' => _('Der Name der Kategorie wurde geändert.')];
-            $this->redirect('course/forum/index/index#cat_' . $category_id);
-        }
-
-    }
-
-    /**
-     * Save the ordering of the categories
-     */
-    function savecats_action()
-    {
-        ForumPerm::check('sort_category', $this->getId());
-
-        $pos = 0;
-        foreach (Request::getArray('categories') as $category_id) {
-            ForumPerm::checkCategoryId($this->getId(), $category_id);
-            ForumCat::setPosition($category_id, $pos);
-            $pos++;
-        }
-
-        $this->render_nothing();
-    }
-
-    /*
-     * Subscribe to the submitted topic and receive mails on new postings
-     *
-     * @param string $topic_id
-     */
-    function abo_action($topic_id)
-    {
-        ForumPerm::check('abo', $this->getId(), $topic_id);
-
-        ForumAbo::add($topic_id);
-        $this->constraint = ForumEntry::getConstraints($topic_id);
-
-        if (Request::isXhr()) {
-            $this->render_template('course/forum/index/_abo_link');
-        } else {
-            switch ($this->constraint['depth']) {
-                case 0:  $msg = _('Sie haben das gesamte Forum abonniert!');break;
-                case 1:  $msg = _('Sie haben diesen Bereich abonniert.');break;
-                default: $msg = _('Sie haben dieses Thema abonniert');break;
-            }
-            $this->flash['messages'] = ['success' => $msg .' '. _('Sie werden nun über jeden neuen Beitrag informiert.')];
-            $this->redirect('course/forum/index/index/' . $topic_id);
-        }
-    }
-
-    /**
-     * Unsubscribe from the passed topic
-     *
-     * @param string $topic_id
-     */
-    function remove_abo_action($topic_id)
-    {
-        ForumPerm::check('abo', $this->getId(), $topic_id);
-
-        ForumAbo::delete($topic_id);
-
-        if (Request::isXhr()) {
-            $this->constraint = ForumEntry::getConstraints($topic_id);
-            $this->render_template('course/forum/index/_abo_link');
-        } else {
-            $this->flash['messages'] = ['success' => _('Abonnement aufgehoben.')];
-            $this->redirect('course/forum/index/index/' . $topic_id);
-        }
-    }
-
-    /**
-     * Generate a pdf-export for the whole forum or the passed subtree
-     *
-     * @param string $parent_id
-     */
-    function pdfexport_action($parent_id = null)
-    {
-        ForumPerm::check('pdfexport', $this->getId(), $parent_id);
-
-        ForumHelpers::createPDF($this->getId(), $parent_id);
-    }
-
-    public function rescue($exception)
-    {
-        if ($exception instanceof AccessDeniedException) {
-            throw new LoginException();
-        }
-
-        return parent::rescue($exception);
-    }
-}
diff --git a/app/controllers/course/forum/recent.php b/app/controllers/course/forum/recent.php
new file mode 100644
index 0000000..2c3fda2
--- /dev/null
+++ b/app/controllers/course/forum/recent.php
@@ -0,0 +1,24 @@
+<?php
+require_once 'ForumBaseController.php';
+
+class Course_Forum_RecentController extends Forum\ForumBaseController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        Navigation::activateItem('course/forum/topics');
+    }
+
+    public function index_action()
+    {
+        PageLayout::setTitle(_('Neueste Beiträge'));
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/recent/Index')
+                ->withProps([
+                    'last_visit' => Request::int('last_visit')
+                ])
+        );
+    }
+}
diff --git a/app/controllers/course/forum/search.php b/app/controllers/course/forum/search.php
new file mode 100644
index 0000000..84172fb
--- /dev/null
+++ b/app/controllers/course/forum/search.php
@@ -0,0 +1,217 @@
+<?php
+require_once 'ForumBaseController.php';
+
+use Forum\ForumDiscussion;
+use Forum\ForumDiscussionType;
+use Forum\DTO\ForumMember;
+use Forum\DTO\ForumTag;
+
+class Course_Forum_SearchController extends Forum\ForumBaseController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        Navigation::activateItem('course/forum');
+    }
+
+    public function index_action()
+    {
+        $topics = DBManager::get()->fetchAll(
+            "SELECT
+                    `ft`.`topic_id`, `ft`.`name`, `fc`.`color`
+                FROM `forum_topics` AS `ft`
+                LEFT JOIN `forum_categories` AS `fc` USING (`category_id`)
+                WHERE `ft`.`range_id` = :course_id
+                ORDER BY `ft`.`position` ASC, `ft`.`mkdate` DESC
+            ",
+            ['course_id' => $this->course_id]
+        );
+
+        $course_members = [];
+        foreach (Context::get()->members as $member) {
+            $course_members[] = [
+                'user_id' => $member['user_id'],
+                'name' => $member['Vorname'] . ' ' . $member['Nachname'],
+                'avatar_url' => Avatar::getAvatar($member['user_id'])->getURL(Avatar::NORMAL),
+                'profile_url' => URLHelper::getLink('dispatch.php/profile', ['username' => $member['username']], true)
+            ];
+        }
+
+        $search_object = $this->buildSearchObject();
+        $all_tags = array_map(fn(ForumTag $tag) => $tag->toRawArray(), ForumTag::getForumTags());
+        $discussion_types = array_map(fn(ForumDiscussionType $discussion_type) => $discussion_type->toRawArray(), ForumDiscussionType::getForumDiscussionType());
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/search/Index')
+                ->withProps([
+                    'search' => $search_object,
+                    'discussions' =>  $this->getResult($search_object),
+                    'topics' => $topics,
+                    'discussion_types' => $discussion_types,
+                    'tags' => $all_tags,
+                    'course_members' => $course_members,
+                ])
+        );
+    }
+
+    private function getResult($search_object): array
+    {
+        if ($this->isSearchObjectEmpty($search_object)) {
+            unset($_SESSION['forum'][$this->course_id]['search']);
+            return [];
+        }
+
+        $query = [
+            "SELECT
+                    discussions.discussion_id,
+                    COUNT(DISTINCT postings.posting_id) AS 'postings_count'
+                FROM `forum_discussions` AS `discussions`
+                LEFT JOIN `forum_postings` AS `postings` USING(`discussion_id`)
+                LEFT JOIN `tags_relations` ON (`tags_relations`.`range_id` = `discussions`.`discussion_id` AND `range_type` = 'forum')
+                WHERE `postings`.`range_id` = :course_id ",
+            [
+                'course_id' => $this->course_id
+            ]
+        ];
+
+        $keyword = $search_object['keyword'];
+        if ($keyword) {
+            $query[0] .= " AND (discussions.title LIKE :keyword OR postings.content LIKE :keyword)";
+            $query[1]["keyword"] = "%$keyword%";
+        }
+
+        if ($search_object['begin']) {
+            $query[0] .= " AND postings.mkdate >= :begin";
+            $query[1]['begin'] = $search_object['begin'];
+        }
+
+        if ($search_object['end']) {
+            $query[0] .= " AND postings.mkdate <= :end";
+            $query[1]['end'] = $search_object['end'];
+        }
+
+        if ($search_object['topic_ids']) {
+            $query[0] .= " AND discussions.topic_id IN (:topic_ids)";
+            $query[1]['topic_ids'] = $search_object['topic_ids'];
+        }
+
+        if ($search_object['discussion_type_ids']) {
+            $query[0] .= " AND discussions.type_id IN (:type_ids)";
+            $query[1]['type_ids'] = $search_object['discussion_type_ids'];
+        }
+
+        if ($search_object['tag_ids']) {
+            $query[0] .= " AND tags_relations.tag_id IN (:tag_ids)";
+            $query[1]['tag_ids'] = $search_object['tag_ids'];
+        }
+
+        if ($search_object['user_ids']) {
+            $query[0] .= " AND postings.user_id IN (:user_ids)";
+            $query[1]['user_ids'] = $search_object['user_ids'];
+        }
+
+        $query[0] .= match ($search_object['discussion_status']) {
+            2 => " AND discussions.closed_at IS NULL", // opens
+            3 => " AND discussions.closed_at IS NOT NULL", // closed
+            default => ""
+        };
+
+        $result =  DBManager::get()->fetchAll(
+            $query[0]." GROUP BY discussions.discussion_id",
+            $query[1]
+        );
+
+        $discussions = ForumDiscussion::findBySQL("discussion_id IN (:discussion_ids)", ['discussion_ids' => array_column($result, 'discussion_id')]);
+
+
+        return array_map(function (ForumDiscussion $discussion) use ($result) {
+            $postings_count = array_find($result, fn($item) => $item['discussion_id'] === $discussion->discussion_id)['postings_count'];
+            $members = array_map(fn(ForumMember $member) => $member->toRawArray(), $discussion->members);
+            $tags = array_map(fn(ForumTag $tag) => $tag->toRawArray(), $discussion->tags);
+
+            return [
+                'id' => $discussion->discussion_id,
+                'title' => $discussion->title,
+                'closed_at' => $discussion->closed_at ? date('c', $discussion->closed_at) : null,
+                'view_count' => (int) $discussion->view_count,
+                'sticky' => (bool) $discussion->sticky,
+                'mkdate' => date('c', $discussion->mkdate),
+                'chdate' => date('c', $discussion->chdate),
+                'topic' => $discussion->topic->toRawArray(),
+                'category' => $discussion->category ? [
+                    'name' => $discussion->category->name,
+                    'color' => $discussion->category->color,
+                ] : [],
+                'discussion_type' => $discussion->discussion_type ? [
+                    'name' => $discussion->discussion_type->name,
+                    'icon' => $discussion->discussion_type->icon,
+                ] : [],
+                'members' => $members,
+                'tags' => $tags,
+                'meta' => [
+                    'postings_count' => (int) $postings_count,
+                    'recent_activity' => $discussion->metadata['recent_activity'] ? date('c', $discussion->metadata['recent_activity']) : null,
+                ]
+            ];
+        }, $discussions);
+    }
+
+    private function isSearchObjectEmpty($search_object): bool {
+        if (
+            $search_object['keyword'] ||
+            $search_object['begin'] ||
+            $search_object['end'] ||
+            $search_object['discussion_status'] ||
+            $search_object['discussion_type_ids'] ||
+            $search_object['tag_ids'] ||
+            $search_object['topic_ids'] ||
+            $search_object['user_ids']
+        ) {
+            return false;
+        }
+
+        return true;
+    }
+
+    private function buildSearchObject(): array
+    {
+        $request = Request::getInstance();
+        if (
+            $request->offsetExists('keyword') ||
+            $request->offsetExists('begin') ||
+            $request->offsetExists('end') ||
+            $request->offsetExists('discussion_status') ||
+            $request->offsetExists('discussion_type_ids') ||
+            $request->offsetExists('tag_ids') ||
+            $request->offsetExists('topic_ids') ||
+            $request->offsetExists('user_ids')
+        ) {
+            $search_object =  [
+                'keyword' => Request::get('keyword'),
+                'begin' => Request::int('begin'),
+                'end' => Request::int('end'),
+                'discussion_status' => Request::int('discussion_status'),
+                'discussion_type_ids' =>  Request::getArray('discussion_type_ids'),
+                'tag_ids' => Request::getArray('tag_ids'),
+                'topic_ids' => Request::getArray('topic_ids'),
+                'user_ids' => Request::getArray('user_ids')
+            ];
+
+            $_SESSION['forum'][$this->course_id]['search'] = $search_object;
+            return $search_object;
+        }
+
+        $session_search = $_SESSION['forum'][$this->course_id]['search'] ?? [];
+        return [
+            'keyword' => $session_search['keyword'] ?? '',
+            'begin' => $session_search['begin'] ?? 0,
+            'end' => $session_search['end'] ?? 0,
+            'discussion_status' => $session_search['discussion_status'] ?? 0,
+            'discussion_type_ids' => $session_search['discussion_type_ids'] ?? [],
+            'tag_ids' => $session_search['tag_ids'] ?? [],
+            'topic_ids' => $session_search['topic_ids'] ?? [],
+            'user_ids' => $session_search['user_ids'] ?? []
+        ];
+    }
+}
diff --git a/app/controllers/course/forum/subscriptions.php b/app/controllers/course/forum/subscriptions.php
new file mode 100644
index 0000000..399c072
--- /dev/null
+++ b/app/controllers/course/forum/subscriptions.php
@@ -0,0 +1,19 @@
+<?php
+require_once 'ForumBaseController.php';
+
+class Course_Forum_SubscriptionsController extends Forum\ForumBaseController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        Navigation::activateItem('course/forum/subscriptions');
+    }
+
+    public function index_action()
+    {
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/subscriptions/Index')
+        );
+    }
+}
diff --git a/app/controllers/course/forum/topics.php b/app/controllers/course/forum/topics.php
new file mode 100644
index 0000000..0070937
--- /dev/null
+++ b/app/controllers/course/forum/topics.php
@@ -0,0 +1,157 @@
+<?php
+require_once 'ForumBaseController.php';
+
+use Forum\ForumCategory;
+use Forum\ForumSubscription;
+use Forum\ForumTopic;
+
+class Course_Forum_TopicsController extends Forum\ForumBaseController
+{
+    public function before_filter(&$action, &$args)
+    {
+        parent::before_filter($action, $args);
+
+        unset($_SESSION['forum'][$this->course_id]['search']);
+
+        Navigation::activateItem('course/forum/topics');
+    }
+
+    public function index_action()
+    {
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/topics/Index')
+        );
+    }
+
+    public function show_action($topic_id)
+    {
+        $topic = ForumTopic::find($topic_id);
+
+        if (!$topic) {
+            throw new AccessDeniedException();
+        }
+
+        PageLayout::setTitle($topic->name);
+
+        $user_subscription = ForumSubscription::findOneBySQL(
+            "subject = :subject AND subject_id = :subject_id AND user_id = :user_id",
+            [
+                'subject' => 'topic',
+                'subject_id' => $topic->getId(),
+                'user_id' => User::findCurrent()->user_id
+            ]
+        );
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/topics/Show')
+                ->withProps([
+                    'topic' => $topic->transformData(),
+                    'category' => $topic->category ? $topic->category->transformData() : [],
+                    'user_subscription' => $user_subscription ? $user_subscription->toRawArray() : [],
+                    'metadata' => [
+                        'postings_count' => (int) $topic->metadata['postings_count'],
+                        'users_count' => (int) $topic->metadata['users_count'],
+                        'recent_activity' => date('c', $topic->metadata['recent_activity'])
+                    ]
+                ])
+        );
+    }
+
+    public function edit_action($topic_id = null)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        if ($topic_id) {
+            PageLayout::setTitle(_('Thema bearbeiten'));
+            $topic = ForumTopic::getCourseTopic($this->course_id, $topic_id);
+
+            if (!$topic) {
+                throw new AccessDeniedException();
+            }
+        } else {
+            PageLayout::setTitle(_('Neues Thema anlegen'));
+            $topic = new ForumTopic();
+            $topic['category_id'] = Request::get('category_id');
+        }
+
+        $categories = DBManager::get()->fetchAll(
+            "SELECT * FROM `forum_categories` WHERE `range_id` = ? ORDER BY `position` ASC, `mkdate` DESC",
+            [$this->course_id]
+        );
+
+        $this->render_vue_app(
+            Studip\VueApp::create('forum/topics/Edit')
+                ->withProps([
+                    'topic' => $topic->transformData(),
+                    'categories' => $categories
+                ])
+        );
+    }
+
+    public function save_action($topic_id = null)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        CSRFProtection::verifyUnsafeRequest();
+
+        if ($topic_id) {
+            $topic = ForumTopic::getCourseTopic($this->course_id, $topic_id);
+            if (!$topic) {
+                throw new AccessDeniedException();
+            }
+        } else {
+            $topic = new ForumTopic();
+            $topic->range_id = $this->course_id;
+        }
+
+        $category = json_decode(Request::get('category'), true);
+
+        if (empty($category['category_id']) && !empty($category['name'])) {
+            $newCategory = ForumCategory::create([
+                'range_id' => $this->course_id,
+                'color' => '#28497C',
+                'name' => $category['name']
+            ]);
+
+            $category['category_id'] = $newCategory->category_id;
+        } else {
+            $topic->category_id = null;
+        }
+
+        if (!empty($category['category_id'])) {
+            $topic->category_id = $category['category_id'];
+        }
+
+        $topic->name = Request::get('name');
+        $topic->description = Request::get('description');
+
+        $topic->store();
+
+        PageLayout::postSuccess(_('Das Thema wurde gespeichert.'));
+
+        $this->relocate('course/forum/topics/show/' . $topic->topic_id);
+    }
+
+    public function delete_action($topic_id)
+    {
+        if (!$this->is_moderator) {
+            throw new AccessDeniedException();
+        }
+
+        $topic = ForumTopic::getCourseTopic($this->course_id, $topic_id);
+
+        if (!$topic) {
+            throw new AccessDeniedException();
+        }
+
+        $topic->delete();
+
+        PageLayout::postSuccess(_('Das Thema wurde gelöscht.'));
+
+        $this->relocate('course/forum/topics');
+    }
+}
diff --git a/app/controllers/course/topics.php b/app/controllers/course/topics.php
index 36e25ec..e955ba1 100644
--- a/app/controllers/course/topics.php
+++ b/app/controllers/course/topics.php
@@ -97,9 +97,6 @@ class Course_TopicsController extends AuthenticatedController
         if (Request::bool('folder')) {
             $topic->connectWithDocumentFolder();
         }
-
-        // create a connection to the module forum (can be anything)
-        // will update title and description automagically
         if (Request::bool('forumthread')) {
             $topic->connectWithForumThread();
         }
diff --git a/app/controllers/institute/basicdata.php b/app/controllers/institute/basicdata.php
index 3a5a751..c1bb1cd 100644
--- a/app/controllers/institute/basicdata.php
+++ b/app/controllers/institute/basicdata.php
@@ -432,14 +432,6 @@ class Institute_BasicdataController extends AuthenticatedController
                 }
             }
 
-            // delete all contents in forum-modules
-            foreach (PluginEngine::getPlugins(ForumModule::class) as $plugin) {
-                $plugin->deleteContents($i_id);  // delete content irrespective of plugin-activation in the seminar
-                if ($plugin->isActivated($i_id)) {   // only show a message, if the plugin is activated, to not confuse the user
-                    $details[] = sprintf(_('Einträge in %s gelöscht.'), $plugin->getPluginName());
-                }
-            }
-
             // Alle Pluginzuordnungen entfernen
             PluginManager::getInstance()->deactivateAllPluginsForRange('inst', $i_id);
 
diff --git a/app/controllers/privacy.php b/app/controllers/privacy.php
index 5598f65..7aa8780 100644
--- a/app/controllers/privacy.php
+++ b/app/controllers/privacy.php
@@ -437,7 +437,7 @@ class PrivacyController extends AuthenticatedController
                 'description' => _('Nachrichten, Kommentare, Blubber, News'),
             ],
             'content' => [
-                'icon'        => Icon::create('forum2'),
+                'icon'        => Icon::create('forum'),
                 'title'       => _('Inhalte'),
                 'description' => _('Courseware, Dateien, Forum, Wiki, Literaturlisten'),
             ],