Art: drag pieces into a new order

Each gallery tile gets a small drag handle (top-left, ✱). Grab it and
drop it anywhere among the others - the tile moves live as you drag
over neighbours, then the new order is saved automatically on drop.

- Artwork gets a `position` column; the gallery lists by position (was
  upload date). New uploads land after everything else.
- New POST /art/reorder endpoint takes an ordered list of ids (one
  shared CSRF token, "reorder-art") and rewrites positions 1..n.
- Migration backfills position from the existing upload-date order via
  ROW_NUMBER(), then drops the bootstrap default so it matches the
  Doctrine mapping.
- New Stimulus controller (art-reorder): native HTML5 drag/drop, no
  library. dragover live-reorders the DOM by comparing cursor x to the
  hovered tile's midpoint; dragend posts the resulting id order and
  shows a small "Saving order… / Order saved" status pill.

Verified: schema validate clean: a throwaway script exercised
persist+reload of a reordered set against the real DB, and a live
browser check dispatched real DragEvents through the actual Stimulus
controller and confirmed the exact POST payload it sent. phpunit 9/9.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

assets/controllers/art_reorder_controller.js

@@ -0,0 +1,94 @@
+import { Controller } from '@hotwired/stimulus';
+
+/*
+ * Drag-to-reorder for the art gallery.
+ *
+ *   <div data-controller="art-reorder"
+ *        data-art-reorder-url-value="/art/reorder"
+ *        data-art-reorder-token-value="...">
+ *     <div data-art-reorder-target="item" data-art-id="5">
+ *       <button draggable="true"
+ *               data-action="dragstart->art-reorder#dragStart dragend->art-reorder#dragEnd">⠿</button>
+ *       ...
+ *     </div>
+ *     ...
+ *   </div>
+ *   <div data-art-reorder-target="status"></div>
+ *
+ * The dragged tile is moved live in the DOM as the pointer crosses other
+ * tiles (dragover, bound on the grid itself via data-action); the new order
+ * is only sent to the server once, on dragend.
+ */
+export default class extends Controller {
+    static targets = ['item', 'status'];
+    static values = { url: String, token: String };
+
+    dragStart(event) {
+        const tile = event.currentTarget.closest('[data-art-reorder-target="item"]');
+        if (!tile) return;
+
+        this.dragEl = tile;
+        this.startOrder = this.currentOrder();
+        tile.classList.add('is-dragging');
+        event.dataTransfer.effectAllowed = 'move';
+        // Firefox requires data to be set for the drag to start at all.
+        event.dataTransfer.setData('text/plain', tile.dataset.artId);
+    }
+
+    dragOver(event) {
+        if (!this.dragEl) return;
+        event.preventDefault();
+
+        const over = event.target.closest('[data-art-reorder-target="item"]');
+        if (!over || over === this.dragEl) return;
+
+        const rect = over.getBoundingClientRect();
+        const before = event.clientX - rect.left < rect.width / 2;
+        over.parentNode.insertBefore(this.dragEl, before ? over : over.nextSibling);
+    }
+
+    drop(event) {
+        event.preventDefault();
+    }
+
+    dragEnd() {
+        if (!this.dragEl) return;
+        this.dragEl.classList.remove('is-dragging');
+
+        const order = this.currentOrder();
+        const changed = order.join(',') !== (this.startOrder || []).join(',');
+        this.dragEl = null;
+
+        if (changed) this.persist(order);
+    }
+
+    currentOrder() {
+        return this.itemTargets.map((el) => el.dataset.artId);
+    }
+
+    async persist(order) {
+        this.showStatus('Saving order…');
+        try {
+            const res = await fetch(this.urlValue, {
+                method: 'POST',
+                credentials: 'same-origin',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ _token: this.tokenValue, order }),
+            });
+            if (!res.ok) throw new Error(`HTTP ${res.status}`);
+            this.showStatus('Order saved');
+        } catch (e) {
+            console.error('art reorder save failed', e);
+            this.showStatus('Could not save the new order — reload and try again', true);
+        }
+    }
+
+    showStatus(text, isError = false) {
+        if (!this.hasStatusTarget) return;
+        clearTimeout(this.statusTimer);
+        this.statusTarget.textContent = text;
+        this.statusTarget.classList.toggle('is-error', isError);
+        this.statusTarget.classList.add('is-visible');
+        this.statusTimer = setTimeout(() => this.statusTarget.classList.remove('is-visible'), isError ? 4000 : 1800);
+    }
+}

assets/styles/app.css

@@ -113,6 +113,47 @@ table.dataTable {
     height: auto;
 }
 
+/* Drag-to-reorder handle, top-left of each tile */
+.art-drag-handle {
+    position: absolute;
+    top: 0.35rem;
+    left: 0.35rem;
+    z-index: 2;
+    width: 1.9rem;
+    height: 1.9rem;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    border: 1px solid var(--bs-border-color);
+    border-radius: 0.35rem;
+    background: var(--bs-body-bg);
+    color: var(--bs-secondary-color);
+    opacity: 0.8;
+    cursor: grab;
+    line-height: 1;
+}
+.art-drag-handle:hover { opacity: 1; color: var(--bs-body-color); }
+.art-drag-handle:active { cursor: grabbing; }
+.art-tile.is-dragging { opacity: 0.4; }
+.art-tile.is-drag-over .card { outline: 2px dashed var(--bs-primary); outline-offset: 2px; }
+
+.art-reorder-status {
+    position: fixed;
+    right: 1rem;
+    bottom: 1rem;
+    z-index: 1080;
+    padding: 0.4rem 0.85rem;
+    border-radius: 2rem;
+    background: var(--bs-body-color);
+    color: var(--bs-body-bg);
+    font-size: 0.85rem;
+    opacity: 0;
+    pointer-events: none;
+    transition: opacity 0.2s ease;
+}
+.art-reorder-status.is-visible { opacity: 0.92; }
+.art-reorder-status.is-error { background: var(--bs-danger); color: #fff; }
+
 /* --- Tracker: unfoldable stat blocks --------------------------------- */
 [data-bs-toggle="collapse"] .sb-caret {
     display: inline-block;

migrations/Version20260915151210.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20260915151210 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add artwork.position for the drag-to-reorder gallery, backfilled by upload date';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE artwork ADD position INT NOT NULL DEFAULT 0');
+
+        // Backfill existing rows so the gallery keeps its current (upload-date) order
+        // until someone drags a piece; new uploads get their position in PHP.
+        $this->addSql(<<<'SQL'
+            UPDATE artwork a
+            JOIN (
+                SELECT id, ROW_NUMBER() OVER (ORDER BY uploaded_at ASC, id ASC) AS rn
+                FROM artwork
+            ) ranked ON ranked.id = a.id
+            SET a.position = ranked.rn
+            SQL);
+
+        // Drop the bootstrap default now that every row has a real position;
+        // the mapping has no default, so schema:validate expects none either.
+        $this->addSql('ALTER TABLE artwork CHANGE position position INT NOT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE artwork DROP position');
+    }
+}

src/Controller/ArtController.php

@@ -12,6 +12,7 @@ use Symfony\Component\HttpFoundation\BinaryFileResponse;
 use Symfony\Component\HttpFoundation\File\Exception\FileException;
 use Symfony\Component\HttpFoundation\File\UploadedFile;
 use Symfony\Component\HttpFoundation\HeaderUtils;
+use Symfony\Component\HttpFoundation\JsonResponse;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\Attribute\Route;
@@ -30,12 +31,43 @@ class ArtController extends AbstractController
     public function index(ArtworkRepository $repo): Response
     {
         return $this->render('art/index.html.twig', [
-            'artworks' => $repo->findBy([], ['uploadedAt' => 'DESC']),
+            'artworks' => $repo->findAllOrdered(),
         ]);
     }
 
+    /**
+     * Persists a drag-reordered gallery: body is {_token, order: [id, id, ...]}.
+     */
+    #[Route('/art/reorder', name: 'app_art_reorder', methods: ['POST'])]
+    public function reorder(Request $request, ArtworkRepository $repo, EntityManagerInterface $em): JsonResponse
+    {
+        $payload = json_decode($request->getContent(), true) ?? [];
+
+        if (!$this->isCsrfTokenValid('reorder-art', (string) ($payload['_token'] ?? ''))) {
+            return $this->json(['error' => 'Invalid CSRF token.'], Response::HTTP_BAD_REQUEST);
+        }
+
+        $order = array_map('intval', \is_array($payload['order'] ?? null) ? $payload['order'] : []);
+        if (!$order) {
+            return $this->json(['error' => 'No order given.'], Response::HTTP_BAD_REQUEST);
+        }
+
+        $byId = [];
+        foreach ($repo->findBy(['id' => $order]) as $artwork) {
+            $byId[$artwork->getId()] = $artwork;
+        }
+
+        $position = 1;
+        foreach ($order as $id) {
+            $byId[$id]?->setPosition($position++);
+        }
+        $em->flush();
+
+        return $this->json(['ok' => true]);
+    }
+
     #[Route('/art/upload', name: 'app_art_upload', methods: ['GET', 'POST'])]
-    public function upload(Request $request, EntityManagerInterface $em): Response
+    public function upload(Request $request, EntityManagerInterface $em, ArtworkRepository $repo): Response
     {
         $artwork = new Artwork();
         $form = $this->createForm(ArtworkType::class, $artwork);
@@ -62,7 +94,8 @@ class ArtController extends AbstractController
                 ->setFilename($stored)
                 ->setOriginalName($file->getClientOriginalName())
                 ->setMimeType($file->getClientMimeType())
-                ->setSize((int) (@filesize($this->artDir.'/'.$stored) ?: 0));
+                ->setSize((int) (@filesize($this->artDir.'/'.$stored) ?: 0))
+                ->setPosition($repo->nextPosition());
 
             $em->persist($artwork);
             $em->flush();

src/Entity/Artwork.php

@@ -36,6 +36,10 @@ class Artwork
     #[ORM\Column(type: Types::DATETIME_IMMUTABLE)]
     private \DateTimeImmutable $uploadedAt;
 
+    /** Manual sort order for the gallery; smaller sorts first. Set on upload, changed by drag-reorder. */
+    #[ORM\Column(type: Types::INTEGER)]
+    private int $position = 0;
+
     public function __construct()
     {
         $this->uploadedAt = new \DateTimeImmutable();
@@ -110,4 +114,16 @@ class Artwork
     {
         return $this->uploadedAt;
     }
+
+    public function getPosition(): int
+    {
+        return $this->position;
+    }
+
+    public function setPosition(int $position): static
+    {
+        $this->position = $position;
+
+        return $this;
+    }
 }

src/Repository/ArtworkRepository.php

@@ -15,4 +15,21 @@ class ArtworkRepository extends ServiceEntityRepository
     {
         parent::__construct($registry, Artwork::class);
     }
+
+    /** The gallery order: manual position, oldest upload first as a tiebreak. */
+    public function findAllOrdered(): array
+    {
+        return $this->findBy([], ['position' => 'ASC', 'uploadedAt' => 'ASC']);
+    }
+
+    /** Where a newly uploaded piece belongs: after everything already in the gallery. */
+    public function nextPosition(): int
+    {
+        $max = $this->createQueryBuilder('a')
+            ->select('MAX(a.position)')
+            ->getQuery()
+            ->getSingleScalarResult();
+
+        return ((int) $max) + 1;
+    }
 }

templates/art/index.html.twig

@@ -15,22 +15,33 @@
             </div>
         </div>
     {% else %}
-        <div class="row row-cols-1 row-cols-sm-2 row-cols-md-3 row-cols-lg-4 g-3">
+        <p class="text-body-secondary small mb-2">Drag the <span class="art-drag-handle d-inline-flex">&#10021;</span> handle to reorder.</p>
+        <div class="row row-cols-1 row-cols-sm-2 row-cols-md-3 row-cols-lg-4 g-3 art-grid"
+             data-controller="art-reorder"
+             data-art-reorder-url-value="{{ path('app_art_reorder') }}"
+             data-art-reorder-token-value="{{ csrf_token('reorder-art') }}"
+             data-action="dragover->art-reorder#dragOver drop->art-reorder#drop">
             {% for art in artworks %}
-                <div class="col">
-                    <a href="{{ path('app_art_show', {id: art.id}) }}" class="card shadow-sm h-100 text-decoration-none text-body">
-                        <div class="art-thumb">
-                            <img src="{{ path('app_art_file', {id: art.id}) }}" alt="{{ art.name }}" loading="lazy">
-                        </div>
-                        <div class="card-body py-2">
-                            <div class="fw-semibold text-truncate" title="{{ art.name }}">{{ art.name }}</div>
-                            <div class="text-body-secondary small">
-                                {{ art.uploadedAt|date('Y-m-d') }} · {{ (art.size / 1024)|round }} KB
+                <div class="col art-tile" data-art-reorder-target="item" data-art-id="{{ art.id }}">
+                    <div class="card shadow-sm h-100 position-relative">
+                        <button type="button" class="art-drag-handle" draggable="true"
+                                data-action="dragstart->art-reorder#dragStart dragend->art-reorder#dragEnd"
+                                title="Drag to reorder" aria-label="Drag to reorder {{ art.name }}">&#10021;</button>
+                        <a href="{{ path('app_art_show', {id: art.id}) }}" class="text-decoration-none text-body">
+                            <div class="art-thumb">
+                                <img src="{{ path('app_art_file', {id: art.id}) }}" alt="{{ art.name }}" loading="lazy">
                             </div>
-                        </div>
-                    </a>
+                            <div class="card-body py-2">
+                                <div class="fw-semibold text-truncate" title="{{ art.name }}">{{ art.name }}</div>
+                                <div class="text-body-secondary small">
+                                    {{ art.uploadedAt|date('Y-m-d') }} · {{ (art.size / 1024)|round }} KB
+                                </div>
+                            </div>
+                        </a>
+                    </div>
                 </div>
             {% endfor %}
         </div>
+        <div class="art-reorder-status" data-art-reorder-target="status" aria-live="polite"></div>
     {% endif %}
 {% endblock %}

tests/Entity/ArtworkTest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Tests\Entity;
+
+use App\Entity\Artwork;
+use PHPUnit\Framework\TestCase;
+
+class ArtworkTest extends TestCase
+{
+    public function testPositionDefaultsToZeroAndIsSettable(): void
+    {
+        $art = new Artwork();
+
+        self::assertSame(0, $art->getPosition());
+
+        $art->setPosition(3);
+
+        self::assertSame(3, $art->getPosition());
+    }
+}