Add PDF signature zone availability checks

Introduce `PDFSignatureZoneAvailable` service to check available PDF signature zones. Updated `WorkflowAddSignatureController` to use the new service. Added unit tests to verify the correctness of the functionality.

src/Bundle/ChillDocStoreBundle/Tests/Service/Signature/PDFSignatureZoneAvailableTest.php

@@ -0,0 +1,76 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Tests\Service\Signature;
+
+use Chill\DocStoreBundle\Entity\StoredObject;
+use Chill\DocStoreBundle\Service\Signature\PDFPage;
+use Chill\DocStoreBundle\Service\Signature\PDFSignatureZone;
+use Chill\DocStoreBundle\Service\Signature\PDFSignatureZoneAvailable;
+use Chill\DocStoreBundle\Service\Signature\PDFSignatureZoneParser;
+use Chill\DocStoreBundle\Service\StoredObjectManagerInterface;
+use Chill\MainBundle\Entity\Workflow\EntityWorkflow;
+use Chill\MainBundle\Entity\Workflow\EntityWorkflowSignatureStateEnum;
+use Chill\MainBundle\Workflow\EntityWorkflowManager;
+use Chill\MainBundle\Workflow\WorkflowTransitionContextDTO;
+use Chill\PersonBundle\Entity\Person;
+use PHPUnit\Framework\TestCase;
+use Prophecy\PhpUnit\ProphecyTrait;
+use Symfony\Component\Clock\MockClock;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class PDFSignatureZoneAvailableTest extends TestCase
+{
+    use ProphecyTrait;
+
+    public function testGetAvailableSignatureZones(): void
+    {
+        $clock = new MockClock();
+
+        $storedObject = new StoredObject();
+        $storedObject->registerVersion(type: 'application/pdf');
+
+        $entityWorkflow = new EntityWorkflow();
+        $dto1 = new WorkflowTransitionContextDTO($entityWorkflow);
+        $dto1->futurePersonSignatures[] = new Person();
+        $entityWorkflow->setStep('step1', $dto1, 'transition1', $clock->now());
+        $signature = $entityWorkflow->getCurrentStep()->getSignatures()->first();
+        $signature->setZoneSignatureIndex(1)->setState(EntityWorkflowSignatureStateEnum::SIGNED);
+
+        $entityWorkflowManager = $this->prophesize(EntityWorkflowManager::class);
+        $entityWorkflowManager->getAssociatedStoredObject($entityWorkflow)->willReturn($storedObject);
+
+        $storedObjectManager = $this->prophesize(StoredObjectManagerInterface::class);
+        $storedObjectManager->read($storedObject)->willReturn('fake-content');
+
+        $parser = $this->prophesize(PDFSignatureZoneParser::class);
+        $parser->findSignatureZones('fake-content')->willReturn([
+            $zone1 = new PDFSignatureZone(1, 0.0, 10.0, 20.0, 20.0, new PDFPage(1, 500, 500)),
+            $zone2 = new PDFSignatureZone(2, 0.0, 10.0, 20.0, 20.0, new PDFPage(1, 500, 500)),
+        ]);
+
+        $filter = new PDFSignatureZoneAvailable(
+            $entityWorkflowManager->reveal(),
+            $parser->reveal(),
+            $storedObjectManager->reveal(),
+        );
+
+        $actual = $filter->getAvailableSignatureZones($entityWorkflow);
+
+        self::assertNotContains($zone1, $actual);
+        self::assertContains($zone2, $actual);
+        self::assertCount(1, $actual, 'there should be only one remaining zone');
+    }
+}