feature #787 [Platform][Mistral] Add ImageUrlNormalizer (franzwilding)

This PR was squashed before being merged into the main branch.

Discussion
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[Platform][Mistral] Add `ImageUrlNormalizer`

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | yes
| Docs?         | no
| License       | MIT

The mistral platform factory gets a contract per default as an argument, so all the internal normalizers will not be used. This PR changes this by adding a custom MistralContract that will be used (like in the openAI birdge).

This PR also adds an imageUrl normalizer, since the mistral chat api supports image_urls as well.

Commits
-------

c1227e4 [Platform][Mistral] Add `ImageUrlNormalizer`

Author: OskarStark

src/platform/src/Bridge/Mistral/Contract/ImageUrlNormalizer.php

@@ -0,0 +1,46 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\Platform\Bridge\Mistral\Contract;
+
+use Symfony\AI\Platform\Bridge\Mistral\Mistral;
+use Symfony\AI\Platform\Contract\Normalizer\ModelContractNormalizer;
+use Symfony\AI\Platform\Message\Content\ImageUrl;
+use Symfony\AI\Platform\Model;
+
+/**
+ * @author Franz Mayr-Wilding
+ */
+class ImageUrlNormalizer extends ModelContractNormalizer
+{
+    /**
+     * @param ImageUrl $data
+     *
+     * @return array{type: 'image_url', image_url: string}
+     */
+    public function normalize(mixed $data, ?string $format = null, array $context = []): array
+    {
+        return [
+            'type' => 'image_url',
+            'image_url' => $data->getUrl(),
+        ];
+    }
+
+    protected function supportedDataClass(): string
+    {
+        return ImageUrl::class;
+    }
+
+    protected function supportsModel(Model $model): bool
+    {
+        return $model instanceof Mistral;
+    }
+}

src/platform/src/Bridge/Mistral/PlatformFactory.php

@@ -13,6 +13,7 @@
 
 use Symfony\AI\Platform\Bridge\Mistral\Contract\DocumentNormalizer;
 use Symfony\AI\Platform\Bridge\Mistral\Contract\DocumentUrlNormalizer;
+use Symfony\AI\Platform\Bridge\Mistral\Contract\ImageUrlNormalizer;
 use Symfony\AI\Platform\Bridge\Mistral\Contract\ToolNormalizer;
 use Symfony\AI\Platform\Contract;
 use Symfony\AI\Platform\ModelCatalog\ModelCatalogInterface;
@@ -41,6 +42,7 @@ public static function create(
                 new ToolNormalizer(),
                 new DocumentNormalizer(),
                 new DocumentUrlNormalizer(),
+                new ImageUrlNormalizer(),
             ),
         );
     }

src/platform/tests/Bridge/Mistral/Contract/ImageUrlNormalizerTest.php

@@ -0,0 +1,64 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Bridge\Mistral\Contract;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Symfony\AI\Platform\Bridge\Mistral\Contract\ImageUrlNormalizer;
+use Symfony\AI\Platform\Bridge\Mistral\Mistral;
+use Symfony\AI\Platform\Contract;
+use Symfony\AI\Platform\Message\Content\ImageUrl;
+
+final class ImageUrlNormalizerTest extends TestCase
+{
+    public function testSupportsNormalization()
+    {
+        $normalizer = new ImageUrlNormalizer();
+
+        $this->assertTrue($normalizer->supportsNormalization(new ImageUrl('https://example.com/image.png'), context: [
+            Contract::CONTEXT_MODEL => new Mistral('mistral-large-latest'),
+        ]));
+        $this->assertFalse($normalizer->supportsNormalization('not a image url'));
+    }
+
+    public function testGetSupportedTypes()
+    {
+        $normalizer = new ImageUrlNormalizer();
+
+        $expected = [
+            ImageUrl::class => true,
+        ];
+
+        $this->assertSame($expected, $normalizer->getSupportedTypes(null));
+    }
+
+    #[DataProvider('normalizeDataProvider')]
+    public function testNormalize(ImageUrl $file, array $expected)
+    {
+        $normalizer = new ImageUrlNormalizer();
+
+        $normalized = $normalizer->normalize($file);
+
+        $this->assertEquals($expected, $normalized);
+    }
+
+    public static function normalizeDataProvider(): iterable
+    {
+        yield 'image with url' => [
+            new ImageUrl('https://example.com/image.png'),
+            [
+                'type' => 'image_url',
+                'image_url' => 'https://example.com/image.png',
+            ],
+        ];
+    }
+}