Add LockTokenParser::parseIfCondition method and corresponding tests

- Implemented the `parseIfCondition` method in `LockTokenParser` to extract lock tokens from `if` headers.
- Added `LockTokenParserTest` with multiple test cases using data providers to validate parsing logic, including scenarios with no headers, resource URIs, and "not" conditions.

src/Bundle/ChillDocStoreBundle/Dav/Utils/LockTokenParser.php

@@ -40,4 +40,19 @@ final readonly class LockTokenParser
 
         return $token;
     }
+
+    public function parseIfCondition(Request $request): ?string
+    {
+        $if = $request->headers->get('if');
+
+        if (null === $if) {
+            return null;
+        }
+
+        if (preg_match('/\((?:not\s+)?<([^>]+)>/i', $if, $matches)) {
+            return $matches[1];
+        }
+
+        return null;
+    }
 }

src/Bundle/ChillDocStoreBundle/Tests/Dav/Utils/LockTokenParserTest.php

@@ -0,0 +1,70 @@
+<?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 Chill\DocStoreBundle\Tests\Dav\Utils;
+
+use Chill\DocStoreBundle\Dav\Utils\LockTokenParser;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * @internal
+ *
+ * @coversNothing
+ */
+class LockTokenParserTest extends TestCase
+{
+    private LockTokenParser $parser;
+
+    protected function setUp(): void
+    {
+        $this->parser = new LockTokenParser();
+    }
+
+    /**
+     * @dataProvider provideIfConditions
+     */
+    public function testParseIfCondition(string $ifHeader, ?string $expectedToken): void
+    {
+        $request = new Request();
+        $request->headers->set('if', $ifHeader);
+
+        $this->assertSame($expectedToken, $this->parser->parseIfCondition($request));
+    }
+
+    public function provideIfConditions(): array
+    {
+        return [
+            'standard lock token' => [
+                '(<opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>)',
+                'opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6',
+            ],
+            'with resource uri' => [
+                '<http://www.ics.uci.edu/users/f/fielding/index.html> (<opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>)',
+                'opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6',
+            ],
+            'no match' => [
+                'some other value',
+                null,
+            ],
+            'with NOT' => [
+                '(Not <opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>)',
+                'opaquelocktoken:f81d4fae-7dec-11d0-a765-00a0c91e6bf6',
+            ],
+        ];
+    }
+
+    public function testParseIfConditionWithNoHeader(): void
+    {
+        $request = new Request();
+        $this->assertNull($this->parser->parseIfCondition($request));
+    }
+}