Introduce schema component

src/Schema/Content/PromptMessage.php

@@ -0,0 +1,88 @@
+<?php
+
+/*
+ * This file is part of the official PHP MCP SDK.
+ *
+ * A collaboration between Symfony and the PHP Foundation.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Mcp\Schema\Content;
+
+use Mcp\Exception\InvalidArgumentException;
+use Mcp\Schema\Enum\Role;
+
+/**
+ * Describes a message returned as part of a prompt.
+ *
+ * @phpstan-import-type TextContentData from TextContent
+ * @phpstan-import-type ImageContentData from ImageContent
+ * @phpstan-import-type AudioContentData from AudioContent
+ * @phpstan-import-type EmbeddedResourceData from EmbeddedResource
+ *
+ * @phpstan-type PromptMessageData array{
+ *     role: string,
+ *     content: TextContentData|ImageContentData|AudioContentData|EmbeddedResourceData,
+ * }
+ *
+ * @author Kyrian Obikwelu <koshnawaza@gmail.com>
+ */
+class PromptMessage extends Content
+{
+    /**
+     * Create a new PromptMessage instance.
+     *
+     * @param Role                                                   $role    The role of the message
+     * @param TextContent|ImageContent|AudioContent|EmbeddedResource $content The content of the message
+     */
+    public function __construct(
+        public readonly Role $role,
+        public readonly TextContent|ImageContent|AudioContent|EmbeddedResource $content,
+    ) {
+        parent::__construct('prompt');
+    }
+
+    /**
+     * @param PromptMessageData $data
+     */
+    public static function fromArray(array $data): self
+    {
+        if (!isset($data['role']) || !\is_string($data['role'])) {
+            throw new InvalidArgumentException('Missing or invalid "role" in PromptMessage data.');
+        }
+        if (!isset($data['content']) || !\is_array($data['content'])) {
+            throw new InvalidArgumentException('Missing or invalid "content" in PromptMessage data.');
+        }
+
+        $contentData = $data['content'];
+        $contentType = $contentData['type'] ?? null;
+
+        $content = match ($contentType) {
+            'text' => TextContent::fromArray($contentData),
+            'image' => ImageContent::fromArray($contentData),
+            'audio' => AudioContent::fromArray($contentData),
+            'resource' => EmbeddedResource::fromArray($contentData),
+            default => throw new InvalidArgumentException(\sprintf('Invalid content type "%s" for PromptMessage.', $contentType)),
+        };
+
+        return new self(Role::from($data['role']), $content);
+    }
+
+    /**
+     * Convert the message to an array.
+     *
+     * @return array{
+     *     role: string,
+     *     content: TextContent|ImageContent|AudioContent|EmbeddedResource
+     * }
+     */
+    public function jsonSerialize(): array
+    {
+        return [
+            'role' => $this->role->value,
+            'content' => $this->content,
+        ];
+    }
+}