Use MessageBagInterface instead of concrete MessageBag implementation

src/Bridge/Anthropic/ModelHandler.php

@@ -5,7 +5,7 @@
 namespace PhpLlm\LlmChain\Bridge\Anthropic;
 
 use PhpLlm\LlmChain\Exception\RuntimeException;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Model;
 use PhpLlm\LlmChain\Model\Response\ResponseInterface as LlmResponse;
 use PhpLlm\LlmChain\Model\Response\StreamResponse;
@@ -33,12 +33,12 @@ public function __construct(
 
     public function supports(Model $model, array|string|object $input): bool
     {
-        return $model instanceof Claude && $input instanceof MessageBag;
+        return $model instanceof Claude && $input instanceof MessageBagInterface;
     }
 
     public function request(Model $model, object|array|string $input, array $options = []): ResponseInterface
     {
-        Assert::isInstanceOf($input, MessageBag::class);
+        Assert::isInstanceOf($input, MessageBagInterface::class);
 
         $system = $input->getSystemMessage();
         $body = array_merge($options, [

src/Bridge/Meta/LlamaPromptConverter.php

@@ -8,13 +8,13 @@
 use PhpLlm\LlmChain\Model\Message\AssistantMessage;
 use PhpLlm\LlmChain\Model\Message\Content\Image;
 use PhpLlm\LlmChain\Model\Message\Content\Text;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Message\SystemMessage;
 use PhpLlm\LlmChain\Model\Message\UserMessage;
 
 final class LlamaPromptConverter
 {
-    public function convertToPrompt(MessageBag $messageBag): string
+    public function convertToPrompt(MessageBagInterface $messageBag): string
     {
         $messages = [];
 

src/Bridge/Ollama/LlamaModelHandler.php

@@ -6,7 +6,7 @@
 
 use PhpLlm\LlmChain\Bridge\Meta\Llama;
 use PhpLlm\LlmChain\Exception\RuntimeException;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Model;
 use PhpLlm\LlmChain\Model\Response\ResponseInterface as LlmResponse;
 use PhpLlm\LlmChain\Model\Response\TextResponse;
@@ -25,7 +25,7 @@ public function __construct(
 
     public function supports(Model $model, object|array|string $input): bool
     {
-        return $model instanceof Llama && $input instanceof MessageBag;
+        return $model instanceof Llama && $input instanceof MessageBagInterface;
     }
 
     public function request(Model $model, object|array|string $input, array $options = []): ResponseInterface

src/Bridge/Replicate/LlamaModelClient.php

@@ -6,7 +6,7 @@
 
 use PhpLlm\LlmChain\Bridge\Meta\Llama;
 use PhpLlm\LlmChain\Bridge\Meta\LlamaPromptConverter;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Message\SystemMessage;
 use PhpLlm\LlmChain\Model\Model;
 use PhpLlm\LlmChain\Platform\ModelClient;
@@ -23,13 +23,13 @@ public function __construct(
 
     public function supports(Model $model, object|array|string $input): bool
     {
-        return $model instanceof Llama && $input instanceof MessageBag;
+        return $model instanceof Llama && $input instanceof MessageBagInterface;
     }
 
     public function request(Model $model, object|array|string $input, array $options = []): ResponseInterface
     {
         Assert::isInstanceOf($model, Llama::class);
-        Assert::isInstanceOf($input, MessageBag::class);
+        Assert::isInstanceOf($input, MessageBagInterface::class);
 
         return $this->client->request(sprintf('meta/meta-%s', $model->getVersion()), 'predictions', [
             'system' => $this->promptConverter->convertMessage($input->getSystemMessage() ?? new SystemMessage('')),

src/Bridge/Replicate/LlamaResponseConverter.php

@@ -6,7 +6,7 @@
 
 use PhpLlm\LlmChain\Bridge\Meta\Llama;
 use PhpLlm\LlmChain\Exception\RuntimeException;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Model;
 use PhpLlm\LlmChain\Model\Response\ResponseInterface as LlmResponse;
 use PhpLlm\LlmChain\Model\Response\TextResponse;
@@ -17,7 +17,7 @@
 {
     public function supports(Model $model, object|array|string $input): bool
     {
-        return $model instanceof Llama && $input instanceof MessageBag;
+        return $model instanceof Llama && $input instanceof MessageBagInterface;
     }
 
     public function convert(HttpResponse $response, array $options = []): LlmResponse

src/Chain.php

@@ -12,7 +12,7 @@
 use PhpLlm\LlmChain\Exception\InvalidArgumentException;
 use PhpLlm\LlmChain\Exception\MissingModelSupport;
 use PhpLlm\LlmChain\Model\LanguageModel;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Response\AsyncResponse;
 use PhpLlm\LlmChain\Model\Response\ResponseInterface;
 
@@ -45,7 +45,7 @@ public function __construct(
     /**
      * @param array<string, mixed> $options
      */
-    public function call(MessageBag $messages, array $options = []): ResponseInterface
+    public function call(MessageBagInterface $messages, array $options = []): ResponseInterface
     {
         $llm = $this->llm;
 

src/Chain/Input.php

@@ -5,7 +5,7 @@
 namespace PhpLlm\LlmChain\Chain;
 
 use PhpLlm\LlmChain\Model\LanguageModel;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 
 final class Input
 {
@@ -14,7 +14,7 @@ final class Input
      */
     public function __construct(
         public readonly LanguageModel $llm,
-        public readonly MessageBag $messages,
+        public readonly MessageBagInterface $messages,
         private array $options,
     ) {
     }

src/Chain/Output.php

@@ -5,7 +5,7 @@
 namespace PhpLlm\LlmChain\Chain;
 
 use PhpLlm\LlmChain\Model\LanguageModel;
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Response\ResponseInterface;
 
 final class Output
@@ -16,7 +16,7 @@ final class Output
     public function __construct(
         public readonly LanguageModel $llm,
         public ResponseInterface $response,
-        public readonly MessageBag $messages,
+        public readonly MessageBagInterface $messages,
         public readonly array $options,
     ) {
     }

src/ChainInterface.php

@@ -4,13 +4,13 @@
 
 namespace PhpLlm\LlmChain;
 
-use PhpLlm\LlmChain\Model\Message\MessageBag;
+use PhpLlm\LlmChain\Model\Message\MessageBagInterface;
 use PhpLlm\LlmChain\Model\Response\ResponseInterface;
 
 interface ChainInterface
 {
     /**
      * @param array<string, mixed> $options
      */
-    public function call(MessageBag $messages, array $options = []): ResponseInterface;
+    public function call(MessageBagInterface $messages, array $options = []): ResponseInterface;
 }

src/Model/Message/MessageBag.php

@@ -4,10 +4,10 @@
 
 namespace PhpLlm\LlmChain\Model\Message;
 
-final class MessageBag implements \Countable, \JsonSerializable
+final class MessageBag implements MessageBagInterface
 {
     /**
-     * @var MessageInterface[]
+     * @var list<MessageInterface>
      */
     private array $messages;
 
@@ -22,7 +22,7 @@ public function add(MessageInterface $message): void
     }
 
     /**
-     * @return MessageInterface[]
+     * @return list<MessageInterface>
      */
     public function getMessages(): array
     {
@@ -48,7 +48,7 @@ public function with(MessageInterface $message): self
         return $messages;
     }
 
-    public function merge(MessageBag $messageBag): self
+    public function merge(MessageBagInterface $messageBag): self
     {
         $messages = clone $this;
         $messages->messages = array_merge($messages->messages, $messageBag->getMessages());

src/Model/Message/MessageBagInterface.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\LlmChain\Model\Message;
+
+interface MessageBagInterface extends \JsonSerializable, \Countable
+{
+    public function add(MessageInterface $message): void;
+
+    /**
+     * @return list<MessageInterface>
+     */
+    public function getMessages(): array;
+
+    public function getSystemMessage(): ?SystemMessage;
+
+    public function with(MessageInterface $message): self;
+
+    public function merge(MessageBagInterface $messageBag): self;
+
+    public function withoutSystemMessage(): self;
+
+    public function prepend(MessageInterface $message): self;
+
+    public function containsImage(): bool;
+}