[MODULES][Collection] Abstracting Collections

components/Collection/Collection.php

@@ -1,11 +0,0 @@
-<?php
-
-declare(strict_types = 1);
-
-namespace Component\Collection;
-
-use App\Core\Modules\Component;
-
-class Collection extends Component
-{
-}

plugins/AttachmentCollections/AttachmentCollections.php

@@ -33,27 +33,95 @@ namespace Plugin\AttachmentCollections;
 
 use App\Core\DB\DB;
 use App\Core\Event;
-use App\Core\Form;
 use function App\Core\I18n\_m;
-use App\Core\Modules\Plugin;
+use App\Core\Modules\Collection;
 use App\Core\Router\RouteLoader;
 use App\Core\Router\Router;
+use App\Entity\Actor;
 use App\Entity\Feed;
 use App\Entity\LocalUser;
-use App\Util\Common;
-use App\Util\Exception\RedirectException;
-use App\Util\Formatting;
 use App\Util\Nickname;
-use Component\Collection\Entity\Collection;
 use Plugin\AttachmentCollections\Controller as C;
+use Plugin\AttachmentCollections\Entity\AttachmentCollection;
 use Plugin\AttachmentCollections\Entity\AttachmentCollectionEntry;
-use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
-use Symfony\Component\Form\Extension\Core\Type\SubmitType;
-use Symfony\Component\Form\Extension\Core\Type\TextType;
 use Symfony\Component\HttpFoundation\Request;
 
-class AttachmentCollections extends Plugin
+class AttachmentCollections extends Collection
 {
+    protected function createCollection(Actor $owner, array $vars, string $name)
+    {
+        $col = AttachmentCollection::create([
+            'name'     => $name,
+            'actor_id' => $owner->getId(),
+        ]);
+        DB::persist($col);
+        DB::persist(AttachmentCollectionEntry::create([
+            'attachment_id' => $vars['vars']['attachment_id'],
+            'note_id'       => $vars['vars']['note_id'],
+            'collection_id' => $col->getId(),
+        ]));
+    }
+    protected function removeItems(Actor $owner, array $vars, $items, array $collections)
+    {
+        return DB::dql(<<<'EOF'
+            DELETE FROM \Plugin\AttachmentCollections\Entity\AttachmentCollectionEntry AS entry
+            WHERE entry.attachment_id = :attach_id AND entry.note_id = :note_id
+            AND entry.collection_id IN (
+                SELECT album.id FROM \Plugin\AttachmentCollections\Entity\AttachmentCollection AS album
+                WHERE album.actor_id = :user_id
+                  AND album.id IN (:ids)
+            )
+            EOF, [
+            'attach_id' => $vars['vars']['attachment_id'],
+            'note_id'   => $vars['vars']['note_id'],
+            'user_id'   => $owner->getId(),
+            'ids'       => $items,
+        ]);
+    }
+
+    protected function addItems(Actor $owner, array $vars, $items, array $collections)
+    {
+        foreach ($items as $id) {
+            // prevent user from putting something in a collection (s)he doesn't own:
+            if (\in_array($id, $collections)) {
+                DB::persist(AttachmentCollectionEntry::create([
+                    'attachment_id' => $vars['vars']['attachment_id'],
+                    'note_id'       => $vars['vars']['note_id'],
+                    'collection_id' => $id,
+                ]));
+            }
+        }
+    }
+
+    protected function shouldAddToRightPanel(Actor $user, $vars, Request $request): bool
+    {
+        return $vars['path'] === 'note_attachment_show';
+    }
+    protected function getCollectionsBy(Actor $owner, ?array $vars = null, bool $ids_only = false): array
+    {
+        if (\is_null($vars)) {
+            $res = DB::findBy(AttachmentCollection::class, ['actor_id' => $owner->getId()]);
+        } else {
+            $res = DB::dql(
+                <<<'EOF'
+                    SELECT entry.collection_id FROM \Plugin\AttachmentCollections\Entity\AttachmentCollectionEntry AS entry
+                    INNER JOIN \Plugin\AttachmentCollections\Entity\AttachmentCollection AS attachment_collection
+                    WITH attachment_collection.id = entry.collection_id
+                    WHERE entry.attachment_id = :attach_id AND entry.note_id = :note_id AND attachment_collection.actor_id = :id
+                    EOF,
+                [
+                    'id'        => $owner->getId(),
+                    'note_id'   => $vars['vars']['note_id'],
+                    'attach_id' => $vars['vars']['attachment_id'],
+                ],
+            );
+        }
+        if (!$ids_only) {
+            return $res;
+        }
+        return array_map(fn ($x) => $x['collection_id'], $res);
+    }
+
     public function onAddRoute(RouteLoader $r): bool
     {
         // View all collections by actor id and nickname
@@ -92,146 +160,4 @@ class AttachmentCollections extends Plugin
         ]));
         return Event::next;
     }
-
-    /**
-     * Append Attachment Collections widget to the right panel.
-     * It's compose of two forms: one to select collections to add
-     * the current attachment to, and another to create a new collection.
-     */
-    public function onAppendRightPanelBlock($vars, Request $request, &$res): bool
-    {
-        if ($vars['path'] !== 'note_attachment_show') {
-            return Event::next;
-        }
-        $user = Common::user();
-        if (\is_null($user)) {
-            return Event::next;
-        }
-
-        $collections = DB::findBy(Collection::class, ['actor_id' => $user->getId()]);
-
-        // add to collection form
-        $attachment_id = $vars['vars']['attachment_id'];
-        $note_id       = $vars['vars']['note_id'];
-        $choices       = [];
-        foreach ($collections as $col) {
-            $choices[$col->getName()] = $col->getId();
-        }
-        $already_selected = DB::dql(
-            <<<'EOF'
-                SELECT entry.collection_id FROM \Plugin\AttachmentCollections\Entity\AttachmentCollectionEntry AS entry
-                INNER JOIN \Component\Collection\Entity\Collection AS attachment_collection
-                WITH attachment_collection.id = entry.collection_id
-                WHERE entry.attachment_id = :attach_id AND entry.note_id = :note_id AND attachment_collection.actor_id = :id
-                EOF,
-            ['attach_id' => $attachment_id, 'note_id' => $note_id, 'id' => $user->getId()],
-        );
-        $already_selected = array_map(fn ($x) => $x['collection_id'], $already_selected);
-        $add_form         = Form::create([
-            ['collections', ChoiceType::class, [
-                'choices'     => $choices,
-                'multiple'    => true,
-                'required'    => false,
-                'choice_attr' => function ($id) use ($already_selected) {
-                    if (\in_array($id, $already_selected)) {
-                        return ['selected' => 'selected'];
-                    }
-                    return [];
-                },
-            ]],
-            ['add', SubmitType::class, [
-                'label' => _m('Add to collections'),
-                'attr'  => [
-                    'title' => _m('Add to collection'),
-                ],
-            ]],
-        ]);
-
-        $add_form->handleRequest($request);
-        if ($add_form->isSubmitted() && $add_form->isValid()) {
-            $collections = $add_form->getData()['collections'];
-            $removed     = array_filter($already_selected, fn ($x) => !\in_array($x, $collections));
-            $added       = array_filter($collections, fn ($x) => !\in_array($x, $already_selected));
-            if (\count($removed) > 0) {
-                DB::dql(<<<'EOF'
-                        DELETE FROM \Plugin\AttachmentCollections\Entity\AttachmentCollectionEntry AS entry
-                        WHERE entry.attachment_id = :attach_id AND entry.note_id = :note_id
-                        AND entry.collection_id IN (
-                            SELECT album.id FROM \Component\Collection\Entity\Collection AS album
-                            WHERE album.actor_id = :user_id
-                              AND album.id IN (:ids)
-                        )
-                    EOF, ['attach_id' => $attachment_id, 'note_id' => $note_id, 'user_id' => $user->getId(), 'ids' => $removed]);
-            }
-            foreach ($added as $cid) {
-                // prevent user from putting something in a collection (s)he doesn't own:
-                if (\in_array($cid, $collections)) {
-                    DB::persist(AttachmentCollectionEntry::create([
-                        'attachment_id' => $attachment_id,
-                        'note_id'       => $note_id,
-                        'collection_id' => $cid,
-                    ]));
-                }
-            }
-            DB::flush();
-            throw new RedirectException();
-        }
-        // add to new collection form
-        $create_form = Form::create([
-            ['name', TextType::class, [
-                'label' => _m('Add to a new collection'),
-                'attr'  => [
-                    'placeholder' => _m('New collection name'),
-                    'required'    => 'required',
-                ],
-                'data' => '',
-            ]],
-            ['create', SubmitType::class, [
-                'label' => _m('Create a new collection'),
-                'attr'  => [
-                    'title' => _m('Create a new collection'),
-                ],
-            ]],
-        ]);
-        $create_form->handleRequest($request);
-        if ($create_form->isSubmitted() && $create_form->isValid()) {
-            $name = $create_form->getData()['name'];
-            $coll = Collection::create([
-                'name'     => $name,
-                'actor_id' => $user->getId(),
-            ]);
-            DB::persist($coll);
-            DB::persist(AttachmentCollectionEntry::create([
-                'attachment_id' => $attachment_id,
-                'note_id'       => $note_id,
-                'collection_id' => $coll->getId(),
-            ]));
-            DB::flush();
-            throw new RedirectException();
-        }
-
-        $res[] = Formatting::twigRenderFile(
-            'AttachmentCollections/widget.html.twig',
-            [
-                'has_collections' => $collections,
-                'add_form'        => $add_form->createView(),
-                'create_form'     => $create_form->createView(),
-            ],
-        );
-        return Event::next;
-    }
-
-    /**
-     * Output our dedicated stylesheet
-     *
-     * @param array $styles stylesheets path
-     *
-     * @return bool hook value; true means continue processing, false means stop
-     */
-    public function onEndShowStyles(array &$styles, string $route): bool
-    {
-        $styles[] = 'plugins/AttachmentCollections/assets/css/widget.css';
-        $styles[] = 'plugins/AttachmentCollections/assets/css/pages.css';
-        return Event::next;
-    }
 }

plugins/AttachmentCollections/Controller/Controller.php

@@ -23,181 +23,35 @@ declare(strict_types = 1);
 
 namespace Plugin\AttachmentCollections\Controller;
 
+use App\Core\Controller\CollectionController;
 use App\Core\DB\DB;
-use App\Core\Form;
-use function App\Core\I18n\_m;
 use App\Core\Router\Router;
-use App\Entity\LocalUser;
+use Plugin\AttachmentCollections\Entity\AttachmentCollection;
-use App\Util\Common;
-use App\Util\Exception\RedirectException;
-use Component\Collection\Entity\Collection;
-use Component\Feed\Util\FeedController;
-use Symfony\Component\Form\Extension\Core\Type\SubmitType;
-use Symfony\Component\Form\Extension\Core\Type\TextType;
-use Symfony\Component\HttpFoundation\Request;
 
-class Controller extends FeedController
+class Controller extends CollectionController
 {
-    public function collectionsByActorNickname(Request $request, string $nickname): array
+    public function createCollection(int $owner_id, string $name)
     {
-        $user = DB::findOneBy(LocalUser::class, ['nickname' => $nickname]);
+        DB::persist(AttachmentCollection::create([
-        return self::collectionsView($request, $user->getId(), $nickname);
+            'name'     => $name,
-    }
+            'actor_id' => $owner_id,
-
-    public function collectionsViewByActorId(Request $request, int $id): array
-    {
-        return self::collectionsView($request, $id, null);
-    }
-
-    /**
-     * Generate Collections page
-     *
-     * @param int     $id       actor id
-     * @param ?string $nickname actor nickname
-     *
-     * @return array twig template options
-     */
-    public function collectionsView(Request $request, int $id, ?string $nickname): array
-    {
-        $collections = DB::findBy(Collection::class, ['actor_id' => $id]);
-
-        // create collection form
-        $create = null;
-        if (Common::user()?->getId() === $id) {
-            $create = Form::create([
-                ['name', TextType::class, [
-                    'label' => _m('Create collection'),
-                    'attr'  => [
-                        'placeholder' => _m('Name'),
-                        'required'    => 'required',
-                    ],
-                    'data' => '',
-                ]],
-                ['add_collection', SubmitType::class, [
-                    'label' => _m('Create collection'),
-                    'attr'  => [
-                        'title' => _m('Create collection'),
-                    ],
-                ]],
-            ]);
-            $create->handleRequest($request);
-            if ($create->isSubmitted() && $create->isValid()) {
-                DB::persist(Collection::create([
-                    'name'     => $create->getData()['name'],
-                    'actor_id' => $id,
         ]));
-                DB::flush();
-                throw new RedirectException();
     }
-        }
+    public function getCollectionUrl(int $owner_id, ?string $owner_nickname, int $collection_id): string
-
-        // We need to inject some functions in twig,
-        // but I don't want to create an environment for this
-        // as twig docs suggest in https://twig.symfony.com/doc/2.x/advanced.html#functions.
-        //
-        // Instead, I'm using an anonymous class to encapsulate
-        // the functions and passing that class to the template.
-        // This is suggested at https://stackoverflow.com/a/50364502.
-        $fn = new class($id, $nickname, $request) {
-            private $id;
-            private $nick;
-            private $request;
-
-            public function __construct($id, $nickname, $request)
     {
-                $this->id      = $id;
+        if (\is_null($owner_nickname)) {
-                $this->nick    = $nickname;
-                $this->request = $request;
-            }
-            // there's already a injected function called path,
-            // that maps to Router::url(name, args), but since
-            // I want to preserve nicknames, I think it's better
-            // to use that getUrl function
-            public function getUrl($cid)
-            {
-                if (\is_null($this->nick)) {
             return Router::url(
                 'collection_notes_view_by_actor_id',
-                        ['id' => $this->id, 'cid' => $cid],
+                ['id' => $owner_id, 'cid' => $collection_id],
             );
         }
         return Router::url(
             'collection_notes_view_by_nickname',
-                    ['nickname' => $this->nick, 'cid' => $cid],
+            ['nickname' => $owner_nickname, 'cid' => $collection_id],
         );
     }
-            // There are many collections in this page and we need two
+    public function getCollectionItems(int $owner_id, $collection_id): array
-            // forms for each one of them: one form to edit the collection's
-            // name and another to remove the collection.
-
-            // creating the edit form
-            public function editForm($collection)
     {
-                $edit = Form::create([
-                    ['name', TextType::class, [
-                        'attr' => [
-                            'placeholder' => 'New name',
-                            'required'    => 'required',
-                        ],
-                        'data' => '',
-                    ]],
-                    ['update_' . $collection->getId(), SubmitType::class, [
-                        'label' => _m('Save'),
-                        'attr'  => [
-                            'title' => _m('Save'),
-                        ],
-                    ]],
-                ]);
-                $edit->handleRequest($this->request);
-                if ($edit->isSubmitted() && $edit->isValid()) {
-                    $collection->setName($edit->getData()['name']);
-                    DB::persist($collection);
-                    DB::flush();
-                    throw new RedirectException();
-                }
-                return $edit->createView();
-            }
-
-            // creating the remove form
-            public function rmForm($collection)
-            {
-                $rm = Form::create([
-                    ['remove_' . $collection->getId(), SubmitType::class, [
-                        'label' => _m('Delete collection'),
-                        'attr'  => [
-                            'title' => _m('Delete collection'),
-                            'class' => 'danger',
-                        ],
-                    ]],
-                ]);
-                $rm->handleRequest($this->request);
-                if ($rm->isSubmitted()) {
-                    DB::remove($collection);
-                    DB::flush();
-                    throw new RedirectException();
-                }
-                return $rm->createView();
-            }
-        };
-
-        return [
-            '_template'      => 'AttachmentCollections/collections.html.twig',
-            'page_title'     => 'Attachment Collections list',
-            'add_collection' => $create?->createView(),
-            'fn'             => $fn,
-            'collections'    => $collections,
-        ];
-    }
-
-    public function collectionNotesByNickname(Request $request, string $nickname, int $cid): array
-    {
-        $user = DB::findOneBy(LocalUser::class, ['nickname' => $nickname]);
-        return self::collectionNotesByActorId($request, $user->getId(), $cid);
-    }
-
-    public function collectionNotesByActorId(Request $request, int $id, int $cid): array
-    {
-        $collection        = DB::findOneBy(Collection::class, ['id' => $cid]);
         [$attachs, $notes] = DB::dql(
             <<<'EOF'
                 SELECT attach, notice FROM \Plugin\AttachmentCollections\Entity\AttachmentCollectionEntry AS entry
@@ -207,13 +61,20 @@ class Controller extends FeedController
                     WITH entry.note_id = notice.id
                 WHERE entry.collection_id = :cid
                 EOF,
-            ['cid' => $cid],
+            ['cid' => $collection_id],
         );
         return [
             '_template'   => 'AttachmentCollections/collection.html.twig',
-            'page_title'  => $collection->getName(),
             'attachments' => array_values($attachs),
             'bare_notes'  => array_values($notes),
         ];
     }
+    public function getCollectionsBy(int $owner_id): array
+    {
+        return DB::findBy(AttachmentCollection::class, ['actor_id' => $owner_id], order_by: ['id' => 'desc']);
+    }
+    public function getCollectionBy(int $owner_id, int $collection_id): AttachmentCollection
+    {
+        return DB::findOneBy(AttachmentCollection::class, ['id' => $collection_id]);
+    }
 }

plugins/AttachmentCollections/Entity/AttachmentCollection.php

@@ -2,12 +2,12 @@
 
 declare(strict_types = 1);
 
-namespace Component\Collection\Entity;
+namespace Plugin\AttachmentCollections\Entity;
 
 use App\Core\Entity;
 use function mb_substr;
 
-class Collection extends Entity
+class AttachmentCollection extends Entity
 {
     // These tags are meant to be literally included and will be populated with the appropriate fields, setters and getters by `bin/generate_entity_fields`
     // {{{ Autocode

plugins/AttachmentCollections/templates/AttachmentCollections/collection.html.twig

@@ -1,18 +1,6 @@
-{% extends 'stdgrid.html.twig' %}
+{% extends 'collections/collection.html.twig' %}
-{% import '/cards/note/view.html.twig' as noteView %}
 
-{% block title %}{{ page_title | trans }}{% endblock %}
+{% block collection_items %}
-
-{% block stylesheets %}
-    {{ parent() }}
-    <link rel="stylesheet" href="{{ asset('assets/default_theme/css/pages/feeds.css') }}" type="text/css">
-{% endblock stylesheets %}
-
-{% block body %}
-    <h1>{{ page_title | trans }}</h1>
-    {# Backwards compatibility with hAtom 0.1 #}
-    <main class="feed" tabindex="0" role="feed">
-        <div class="h-feed hfeed notes">
     {% for key, attachment in attachments %}
         <section class="section-widget section-padding">
             {% include '/cards/attachments/view.html.twig' with {'attachment': attachment, 'note': bare_notes[key], 'title': attachment.getBestTitle(bare_notes[key])} only %}
@@ -22,6 +10,4 @@
     {% else %}
         <div id="empty-notes"><h1>{% trans %}No attachments here.{% endtrans %}</h1></div>
     {% endfor %}
-        </div>
+{% endblock collection_items %}
-    </main>
-{% endblock body %}

public/components/Collection/assets/css/pages.css

@@ -0,0 +1,106 @@
+.collection-add, .collections-list {
+    padding: 10px 12px;
+}
+.collection-add > form > div {
+    display: flex;
+    align-items: flex-end;
+}
+.collection-add > form > div .mb-6 {
+    margin-right: 12px;
+}
+.collection-add > form > div button {
+    margin-top: 0px;
+    margin-bottom: var(--s);
+}
+@media only screen and (max-width:465px) {
+    .collection-add > form, .collection-add > form > div .mb-6 {
+        width: 100%;
+        margin: 0px;
+    }
+    .collection-add > form > div {
+        flex-direction: column;
+    }
+    .collection-add > form > div button {
+        margin-top: var(--s);;
+        margin-bottom: 0px;
+    }
+}
+
+:root {
+    --collections-list-quantity: 3;
+}
+@media only screen and (min:1281px) {
+  :root {
+      --collections-list-quantity: 3;
+  }
+}
+@media only screen and (max-width:1280px) {
+  :root {
+      --collections-list-quantity: 4;
+  }
+}
+@media only screen and (max-width:900px) {
+  :root {
+      --collections-list-quantity: 3;
+  }
+}
+@media only screen and (max-width:700px) {
+  :root {
+      --collections-list-quantity: 2;
+  }
+}
+@media only screen and (max-width:465px) {
+  :root {
+      --collections-list-quantity: 1;
+  }
+}
+
+
+.collections-list {
+    display: grid !important;
+    grid-gap: 12px;
+    grid-template-columns: repeat(var(--collections-list-quantity), 1fr);
+}
+.collections-list h3, .collections-list h2, .collections-list h1 {
+    grid-column-start: 1;
+    grid-column-end: calc(var(--collections-list-quantity) + 1);
+}
+.collections-list .collection-item {
+    border: 2px solid var(--border);
+    border-radius: var(--s);
+    padding: 10px 20px;
+    display: flex;
+    flex-direction: column;
+    position: relative;
+}
+.collections-list .collection-item .name {
+    margin-right: auto;
+    flex-grow: 1;
+    flex-shrink: 1;
+    word-break: break-word;
+    margin-right: 60px;
+}
+.collections-list .collection-item summary {
+    position: absolute;
+    top: 10px;
+    right: 50px;
+    width: 16px;
+}
+.collections-list .collection-item details + details > summary {
+    right: 20px;
+}
+.collections-list .collection-item details {
+    margin-top: 12px;
+}
+.collections-list .collection-item svg {
+    fill: var(--foreground);
+}
+.collections-list .collection-item svg:hover {
+    fill: var(--accent);
+}
+.collections-list .collection-item details label {
+    display: none;
+}
+.collections-list .collection-item details .danger {
+    color: #cb2d2d;
+}

public/components/Collection/assets/css/widget.css

@@ -0,0 +1,17 @@
+.collections {
+    background-color: red;
+}
+.collections .collections-selections-options {
+    display: flex;
+    margin-top: 12px;
+    align-items: center;
+    justify-content: space-between;
+}
+.acollections .collections-selections-options button {
+    margin: 0 !important;
+}
+#add_collections {
+    height: auto !important;
+    max-height: 20rem !important;
+    overflow-y: auto !important;
+}

src/Core/Controller/CollectionController.php

@@ -0,0 +1,216 @@
+<?php
+
+declare(strict_types = 1);
+
+// {{{ License
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// GNU social is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.
+// }}}
+/**
+ * Collections Controller for GNU social
+ *
+ * @package   GNUsocial
+ * @category  Plugin
+ *
+ * @author    Phablulo <phablulo@gmail.com>
+ * @copyright 2018-2019, 2021 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+
+namespace App\Core\Controller;
+
+use App\Core\DB\DB;
+use App\Core\Form;
+use function App\Core\I18n\_m;
+use App\Core\Router\Router;
+use App\Entity\LocalUser;
+use App\Util\Common;
+use App\Util\Exception\RedirectException;
+use Component\Feed\Util\FeedController;
+use Symfony\Component\Form\Extension\Core\Type\SubmitType;
+use Symfony\Component\Form\Extension\Core\Type\TextType;
+use Symfony\Component\HttpFoundation\Request;
+
+abstract class CollectionController extends FeedController
+{
+    protected string $slug        = 'collection';
+    protected string $plural_slug = 'collections';
+    protected string $page_title  = 'collections';
+
+    abstract public function getCollectionUrl(int $owner_id, string $owner_nickname, int $collection_id): string;
+    abstract public function getCollectionItems(int $owner_id, $collection_id): array;
+    abstract public function getCollectionsBy(int $owner_id): array;
+    abstract public function getCollectionBy(int $owner_id, int $collection_id);
+    abstract public function createCollection(int $owner_id, string $name);
+
+    public function collectionsByActorNickname(Request $request, string $nickname): array
+    {
+        $user = DB::findOneBy(LocalUser::class, ['nickname' => $nickname]);
+        return self::collectionsView($request, $user->getId(), $nickname);
+    }
+
+    public function collectionsViewByActorId(Request $request, int $id): array
+    {
+        return self::collectionsView($request, $id, null);
+    }
+
+    /**
+     * Generate Collections page
+     *
+     * @param int     $id       actor id
+     * @param ?string $nickname actor nickname
+     *
+     * @return array twig template options
+     */
+    public function collectionsView(Request $request, int $id, ?string $nickname): array
+    {
+        $collections = $this->getCollectionsBy($id);
+
+        // create collection form
+        $create = null;
+        if (Common::user()?->getId() === $id) {
+            $create = Form::create([
+                ['name', TextType::class, [
+                    'label' => _m('Create ' . $this->slug),
+                    'attr'  => [
+                        'placeholder' => _m('Name'),
+                        'required'    => 'required',
+                    ],
+                    'data' => '',
+                ]],
+                ['add_collection', SubmitType::class, [
+                    'label' => _m('Create ' . $this->slug),
+                    'attr'  => [
+                        'title' => _m('Create ' . $this->slug),
+                    ],
+                ]],
+            ]);
+            $create->handleRequest($request);
+            if ($create->isSubmitted() && $create->isValid()) {
+                $this->createCollection($id, $create->getData()['name']);
+                DB::flush();
+                throw new RedirectException();
+            }
+        }
+
+        // We need to inject some functions in twig,
+        // but I don't want to create an environment for this
+        // as twig docs suggest in https://twig.symfony.com/doc/2.x/advanced.html#functions.
+        //
+        // Instead, I'm using an anonymous class to encapsulate
+        // the functions and passing that class to the template.
+        // This is suggested at https://stackoverflow.com/a/50364502.
+        $fn = new class($id, $nickname, $request, $this, $this->slug) {
+            private $id;
+            private $nick;
+            private $request;
+            private $parent;
+            private $slug;
+
+            public function __construct($id, $nickname, $request, $parent, $slug)
+            {
+                $this->id      = $id;
+                $this->nick    = $nickname;
+                $this->request = $request;
+                $this->parent  = $parent;
+                $this->slug    = $slug;
+            }
+            // there's already a injected function called path,
+            // that maps to Router::url(name, args), but since
+            // I want to preserve nicknames, I think it's better
+            // to use that getUrl function
+            public function getUrl($cid)
+            {
+                return $this->parent->getCollectionUrl($this->id, $this->nick, $cid);
+            }
+            // There are many collections in this page and we need two
+            // forms for each one of them: one form to edit the collection's
+            // name and another to remove the collection.
+
+            // creating the edit form
+            public function editForm($collection)
+            {
+                $edit = Form::create([
+                    ['name', TextType::class, [
+                        'attr' => [
+                            'placeholder' => 'New name',
+                            'required'    => 'required',
+                        ],
+                        'data' => '',
+                    ]],
+                    ['update_' . $collection->getId(), SubmitType::class, [
+                        'label' => _m('Save'),
+                        'attr'  => [
+                            'title' => _m('Save'),
+                        ],
+                    ]],
+                ]);
+                $edit->handleRequest($this->request);
+                if ($edit->isSubmitted() && $edit->isValid()) {
+                    $collection->setName($edit->getData()['name']);
+                    DB::persist($collection);
+                    DB::flush();
+                    throw new RedirectException();
+                }
+                return $edit->createView();
+            }
+
+            // creating the remove form
+            public function rmForm($collection)
+            {
+                $rm = Form::create([
+                    ['remove_' . $collection->getId(), SubmitType::class, [
+                        'label' => _m('Delete ' . $this->slug),
+                        'attr'  => [
+                            'title' => _m('Delete ' . $this->slug),
+                            'class' => 'danger',
+                        ],
+                    ]],
+                ]);
+                $rm->handleRequest($this->request);
+                if ($rm->isSubmitted()) {
+                    DB::remove($collection);
+                    DB::flush();
+                    throw new RedirectException();
+                }
+                return $rm->createView();
+            }
+        };
+
+        return [
+            '_template'      => 'collections/collections.html.twig',
+            'page_title'     => $this->page_title,
+            'add_collection' => $create?->createView(),
+            'fn'             => $fn,
+            'collections'    => $collections,
+        ];
+    }
+
+    public function collectionNotesByNickname(Request $request, string $nickname, int $cid): array
+    {
+        $user = DB::findOneBy(LocalUser::class, ['nickname' => $nickname]);
+        return self::collectionNotesByActorId($request, $user->getId(), $cid);
+    }
+
+    public function collectionNotesByActorId(Request $request, int $id, int $cid): array
+    {
+        $collection = $this->getCollectionBy($id, $cid);
+        $vars       = $this->getCollectionItems($id, $cid);
+        return array_merge([
+            '_template'  => 'collections/collection.html.twig',
+            'page_title' => $collection->getName(),
+        ], $vars);
+    }
+}

src/Core/Modules/Collection.php

@@ -0,0 +1,157 @@
+<?php
+
+declare(strict_types = 1);
+
+// {{{ License
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// GNU social is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.
+// }}}
+/**
+ * Collections for GNU social
+ *
+ * @package   GNUsocial
+ * @category  Plugin
+ *
+ * @author    Phablulo <phablulo@gmail.com>
+ * @copyright 2018-2019, 2021 Free Software Foundation, Inc http://www.fsf.org
+ * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
+ */
+
+namespace App\Core\Modules;
+
+use App\Core\DB\DB;
+use App\Core\Event;
+use App\Core\Form;
+use function App\Core\I18n\_m;
+use App\Entity\Actor;
+use App\Util\Common;
+use App\Util\Exception\RedirectException;
+use App\Util\Formatting;
+use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
+use Symfony\Component\Form\Extension\Core\Type\SubmitType;
+use Symfony\Component\Form\Extension\Core\Type\TextType;
+use Symfony\Component\HttpFoundation\Request;
+
+abstract class Collection extends Plugin
+{
+    protected string $slug        = 'collection';
+    protected string $plural_slug = 'collections';
+
+    abstract protected function createCollection(Actor $owner, array $vars, string $name);
+    abstract protected function removeItems(Actor $owner, array $vars, $items, array $collections);
+    abstract protected function addItems(Actor $owner, array $vars, $items, array $collections);
+
+    abstract protected function shouldAddToRightPanel(Actor $user, $vars, Request $request): bool;
+    abstract protected function getCollectionsBy(Actor $owner, ?array $vars = null, bool $ids_only = false): array;
+    /**
+     * Append Collections widget to the right panel.
+     * It's compose of two forms: one to select collections to add
+     * the current item to, and another to create a new collection.
+     */
+    public function onAppendRightPanelBlock($vars, Request $request, &$res): bool
+    {
+        $user = Common::actor();
+        if (\is_null($user)) {
+            return Event::next;
+        }
+        if (!$this->shouldAddToRightPanel($user, $vars, $request)) {
+            return Event::next;
+        }
+        $collections = $this->getCollectionsBy($user);
+
+        // form: add to collection
+        $choices = [];
+        foreach ($collections as $col) {
+            $choices[$col->getName()] = $col->getId();
+        }
+        $already_selected = $this->getCollectionsBy($user, $vars, true);
+        $add_form         = Form::create([
+            ['collections', ChoiceType::class, [
+                'choices'     => $choices,
+                'multiple'    => true,
+                'required'    => false,
+                'choice_attr' => function ($id) use ($already_selected) {
+                    if (\in_array($id, $already_selected)) {
+                        return ['selected' => 'selected'];
+                    }
+                    return [];
+                },
+            ]],
+            ['add', SubmitType::class, [
+                'label' => _m('Add to ' . $this->plural_slug),
+                'attr'  => [
+                    'title' => _m('Add to ' . $this->plural_slug),
+                ],
+            ]],
+        ]);
+        $add_form->handleRequest($request);
+        if ($add_form->isSubmitted() && $add_form->isValid()) {
+            $collections = $add_form->getData()['collections'];
+            $removed     = array_filter($already_selected, fn ($x) => !\in_array($x, $collections));
+            $added       = array_filter($collections, fn ($x) => !\in_array($x, $already_selected));
+            if (\count($removed) > 0) {
+                $this->removeItems($user, $vars, $removed, $collections);
+            }
+            if (\count($added) > 0) {
+                $this->addItems($user, $vars, $added, $collections);
+            }
+            DB::flush();
+            throw new RedirectException();
+        }
+
+        // form: add to new collection
+        $create_form = Form::create([
+            ['name', TextType::class, [
+                'label' => _m('Add to a new ' . $this->slug),
+                'attr'  => [
+                    'placeholder' => _m('New ' . $this->slug . ' name'),
+                    'required'    => 'required',
+                ],
+                'data' => '',
+            ]],
+            ['create', SubmitType::class, [
+                'label' => _m('Create a new ' . $this->slug),
+                'attr'  => [
+                    'title' => _m('Create a new ' . $this->slug),
+                ],
+            ]],
+        ]);
+        $create_form->handleRequest($request);
+        if ($create_form->isSubmitted() && $create_form->isValid()) {
+            $name = $create_form->getData()['name'];
+            $this->createCollection($user, $vars, $name);
+            DB::flush();
+            throw new RedirectException();
+        }
+
+        $res[] = Formatting::twigRenderFile(
+            'collections/widget.html.twig',
+            [
+                'ctitle'          => _m('Add to ' . $this->plural_slug),
+                'user'            => $user,
+                'has_collections' => \count($collections) > 0,
+                'add_form'        => $add_form->createView(),
+                'create_form'     => $create_form->createView(),
+            ],
+        );
+        return Event::next;
+    }
+    public function onEndShowStyles(array &$styles, string $route): bool
+    {
+        $styles[] = 'components/Collection/assets/css/widget.css';
+        $styles[] = 'components/Collection/assets/css/pages.css';
+        return Event::next;
+    }
+}

templates/collections/collection.html.twig

@@ -0,0 +1,20 @@
+{% extends 'stdgrid.html.twig' %}
+{% import '/cards/note/view.html.twig' as noteView %}
+
+{% block title %}{{ page_title | trans }}{% endblock %}
+
+{% block stylesheets %}
+    {{ parent() }}
+    <link rel="stylesheet" href="{{ asset('assets/default_theme/css/pages/feeds.css') }}" type="text/css">
+{% endblock stylesheets %}
+
+{% block body %}
+    <h1>{{ page_title | trans }}</h1>
+    {# Backwards compatibility with hAtom 0.1 #}
+    <main class="feed" tabindex="0" role="feed">
+        <div class="h-feed hfeed notes">
+            {% block collection_items %}
+            {% endblock collection_items %}
+        </div>
+    </main>
+{% endblock body %}

templates/collections/collections.html.twig

@@ -9,19 +9,19 @@
 {% endblock stylesheets %}
 
 {% block body %}
-    <h1>{{ 'Attachment Collections' | trans }}</h1>
+    <h1>{{ page_title | trans }}</h1>
     {# Backwards compatibility with hAtom 0.1 #}
     <main class="feed" tabindex="0" role="feed">
         <div class="h-feed hfeed notes">
             {% if add_collection %}
-                <div class="h-entry hentry note attachment-collection-add">
+                <div class="h-entry hentry note collection-add">
                     {{ form(add_collection) }}
                 </div>
             {% endif %}
-            <div class="h-entry hentry note attachment-collections-list">
+            <div class="h-entry hentry note collections-list">
                 <h3>{{ 'Your collections' | trans }}</h3>
                 {% for col in collections %}
-                    <div class="attachment-collection-item">
+                        <div class="collection-item">
                         <a class="name" href="{{ fn.getUrl(col.id) }}">{{ col.name }}</a>
                         <details title="Expand if you want to edit the collection's name">
                             <summary>

templates/collections/widget.html.twig

@@ -1,7 +1,7 @@
-<section class="section-widget attachment-collections">
+<section class="section-widget collections">
     <details class="section-widget-title-details" title="Expand if you want to access more options.">
         <summary class="section-title-summary">
-            <h2>{% trans %}Add to collection{% endtrans %}</h2>
+            <h2>{{ctitle}}</h2>
             {{ icon('arrow-down', 'icon icon-details-open') | raw }}
         </summary>
         {% if has_collections %}