Minimum integration of messaging convenience

- Add user, assistant and system conv on par with orchestration
- Adapt sample app service class for image input (new api)
- Adapt toDTO to account for OpenAI gen model architecture

Author: rpanackal

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiAssistantMessage.java

@@ -1,8 +1,14 @@
 package com.sap.ai.sdk.foundationmodels.openai;
 
+import com.google.common.annotations.Beta;
 import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestAssistantMessage;
 import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestAssistantMessageContent;
+import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestAssistantMessageContentPart;
+import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestMessageContentPartText;
+import java.util.LinkedList;
+import java.util.List;
 import javax.annotation.Nonnull;
+import lombok.Getter;
 import lombok.Value;
 import lombok.experimental.Accessors;
 
@@ -13,23 +19,53 @@
  */
 @Value
 @Accessors(fluent = true)
-class OpenAiAssistantMessage implements OpenAiMessage {
+public class OpenAiAssistantMessage implements OpenAiMessage {
 
-  /** The role of the message. */
+  /** The role associated with this message. */
   @Nonnull String role = "assistant";
 
   /** The content of the message. */
-  @Nonnull String content;
+  @Getter(onMethod_ = @Beta)
+  @Nonnull
+  OpenAiMessageContent content;
+
+  /**
+   * Creates a new assistant message with the given single message.
+   *
+   * @param singleMessage the single message.
+   */
+  public OpenAiAssistantMessage(@Nonnull final String singleMessage) {
+    content = new OpenAiMessageContent(List.of(new OpenAiTextItem(singleMessage)));
+  }
 
   /**
    * Converts the message to a serializable object.
    *
-   * @return the corresponding {@code ChatCompletionRequestAssistantMessage} object.
+   * @return the corresponding serializable object.
    */
   @Nonnull
-  public ChatCompletionRequestAssistantMessage createDTO() {
+  public ChatCompletionRequestAssistantMessage createChatCompletionRequestMessage()
+      throws IllegalArgumentException {
+    final var itemList = this.content().items();
+    if (itemList.size() == 1 && itemList.get(0) instanceof OpenAiTextItem textItem) {
+      return new ChatCompletionRequestAssistantMessage()
+          .role(ChatCompletionRequestAssistantMessage.RoleEnum.fromValue(role()))
+          .content(ChatCompletionRequestAssistantMessageContent.create(textItem.text()));
+    }
+
+    final var contentList = new LinkedList<ChatCompletionRequestAssistantMessageContentPart>();
+    for (final OpenAiContentItem item : itemList) {
+      if (item instanceof OpenAiTextItem textItem) {
+        contentList.add(
+            new ChatCompletionRequestMessageContentPartText()
+                .type(ChatCompletionRequestMessageContentPartText.TypeEnum.TEXT)
+                .text(textItem.text()));
+      } else if (item instanceof OpenAiImageItem) {
+        throw new IllegalArgumentException("Image items are not supported in assistant messages");
+      }
+    }
     return new ChatCompletionRequestAssistantMessage()
         .role(ChatCompletionRequestAssistantMessage.RoleEnum.fromValue(role()))
-        .content(ChatCompletionRequestAssistantMessageContent.create(content));
+        .content(ChatCompletionRequestAssistantMessageContent.create(contentList));
   }
 }

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiChatCompletionRequest.java

@@ -124,7 +124,8 @@ public OpenAiChatCompletionRequest stop(
 
   CreateChatCompletionRequest toCreateChatCompletionRequest() {
     final var request = new CreateChatCompletionRequest();
-    this.messages().forEach(message -> request.addMessagesItem(message.createDTO()));
+    this.messages()
+        .forEach(message -> request.addMessagesItem(message.createChatCompletionRequestMessage()));
 
     request.stop(
         this.stop() != null ? CreateChatCompletionRequestAllOfStop.create(this.stop()) : null);

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiContentItem.java

@@ -0,0 +1,8 @@
+package com.sap.ai.sdk.foundationmodels.openai;
+
+/**
+ * Represents an item in a {@link OpenAiMessageContent} object.
+ *
+ * @since 1.3.0
+ */
+public sealed interface OpenAiContentItem permits OpenAiTextItem, OpenAiImageItem {}

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiImageItem.java

@@ -0,0 +1,68 @@
+package com.sap.ai.sdk.foundationmodels.openai;
+
+import java.util.Locale;
+import javax.annotation.Nonnull;
+
+/**
+ * Represents an image item in a {@link OpenAiMessageContent} object.
+ *
+ * @param imageUrl the URL of the image
+ * @param detailLevel the detail level of the image (optional)
+ * @since 1.3.0
+ */
+public record OpenAiImageItem(@Nonnull String imageUrl, @Nonnull DetailLevel detailLevel)
+    implements OpenAiContentItem {
+
+  /**
+   * Creates a new image item with the given image URL.
+   *
+   * @param imageUrl the URL of the image
+   * @since 1.3.0
+   */
+  public OpenAiImageItem(@Nonnull final String imageUrl) {
+    this(imageUrl, DetailLevel.AUTO);
+  }
+
+  /**
+   * The detail level of the image.
+   *
+   * @since 1.3.0
+   */
+  public enum DetailLevel {
+    /** Low detail level. */
+    LOW("low"),
+    /** High detail level. */
+    HIGH("high"),
+    /** Automatic detail level. */
+    AUTO("auto");
+
+    private final String level;
+
+    /**
+     * Converts a string to a detail level.
+     *
+     * @param str the string to convert
+     * @return the detail level
+     * @since 1.3.0
+     */
+    @Nonnull
+    static DetailLevel fromString(@Nonnull final String str) {
+      return DetailLevel.valueOf(str.toUpperCase(Locale.ENGLISH));
+    }
+
+    /**
+     * Get the string representation of the DetailLevel
+     *
+     * @return the DetailLevel as string
+     * @since 1.3.0
+     */
+    @Nonnull
+    public String toString() {
+      return level;
+    }
+
+    DetailLevel(@Nonnull final String level) {
+      this.level = level;
+    }
+  }
+}

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiMessage.java

@@ -1,53 +1,85 @@
 package com.sap.ai.sdk.foundationmodels.openai;
 
+import com.google.common.annotations.Beta;
 import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestMessage;
+import java.util.List;
 import javax.annotation.Nonnull;
 
 /**
  * Interface representing convenience wrappers of chat message to the openai service.
  *
  * @since 1.3.0
  */
-public interface OpenAiMessage {
+public sealed interface OpenAiMessage
+    permits OpenAiUserMessage, OpenAiAssistantMessage, OpenAiSystemMessage {
 
   /**
    * A convenience method to create a user message.
    *
-   * @param msg the message content.
+   * @param message the message content.
    * @return the user message.
    */
   @Nonnull
-  static OpenAiMessage user(@Nonnull final String msg) {
-    return new OpenAiUserMessage(msg);
+  static OpenAiUserMessage user(@Nonnull final String message) {
+    return new OpenAiUserMessage(message);
+  }
+
+  /**
+   * A convenience method to create a user message containing only an image.
+   *
+   * @param openAiImageItem the message content.
+   * @return the user message.
+   * @since 1.3.0
+   */
+  @Nonnull
+  static OpenAiUserMessage user(@Nonnull final OpenAiImageItem openAiImageItem) {
+    return new OpenAiUserMessage(new OpenAiMessageContent(List.of(openAiImageItem)));
   }
 
   /**
    * A convenience method to create an assistant message.
    *
-   * @param msg the message content.
+   * @param message the message content.
    * @return the assistant message.
    */
   @Nonnull
-  static OpenAiMessage assistant(@Nonnull final String msg) {
-    return new OpenAiAssistantMessage(msg);
+  static OpenAiAssistantMessage assistant(@Nonnull final String message) {
+    return new OpenAiAssistantMessage(message);
   }
 
   /**
    * A convenience method to create a system message.
    *
-   * @param msg the message content.
+   * @param message the message content.
    * @return the system message.
    */
   @Nonnull
-  static OpenAiMessage system(@Nonnull final String msg) {
-    return new OpenAiSystemMessage(msg);
+  static OpenAiSystemMessage system(@Nonnull final String message) {
+    return new OpenAiSystemMessage(message);
   }
 
+  /**
+   * Returns the role associated with the message.
+   *
+   * @return the role.
+   */
+  @Nonnull
+  String role();
+
+  /**
+   * Returns the content of the message.
+   *
+   * @return the content.
+   */
+  @Nonnull
+  @Beta
+  OpenAiMessageContent content();
+
   /**
    * Converts the message to a serializable object.
    *
    * @return the corresponding serializable object.
    */
   @Nonnull
-  ChatCompletionRequestMessage createDTO();
+  ChatCompletionRequestMessage createChatCompletionRequestMessage() throws IllegalArgumentException;
 }

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiMessageContent.java

@@ -0,0 +1,12 @@
+package com.sap.ai.sdk.foundationmodels.openai;
+
+import java.util.List;
+import javax.annotation.Nonnull;
+
+/**
+ * Represents the content of a chat message.
+ *
+ * @param items a list of the content items
+ * @since 1.3.0
+ */
+public record OpenAiMessageContent(@Nonnull List<OpenAiContentItem> items) {}

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiSystemMessage.java

@@ -1,10 +1,17 @@
 package com.sap.ai.sdk.foundationmodels.openai;
 
+import com.google.common.annotations.Beta;
+import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestMessageContentPartText;
 import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestSystemMessage;
 import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestSystemMessageContent;
+import com.sap.ai.sdk.foundationmodels.openai.model2.ChatCompletionRequestSystemMessageContentPart;
+import java.util.LinkedList;
+import java.util.List;
 import javax.annotation.Nonnull;
+import lombok.Getter;
 import lombok.Value;
 import lombok.experimental.Accessors;
+import lombok.experimental.Tolerate;
 
 /**
  * Represents a chat message as 'system' to OpenAI service. *
@@ -13,23 +20,68 @@
  */
 @Value
 @Accessors(fluent = true)
-class OpenAiSystemMessage implements OpenAiMessage {
+public class OpenAiSystemMessage implements OpenAiMessage {
 
-  /** The role of the message. */
+  /** The role associated with this message. */
   @Nonnull String role = "system";
 
   /** The content of the message. */
-  @Nonnull String content;
+  @Getter(onMethod_ = @Beta)
+  @Nonnull
+  OpenAiMessageContent content;
+
+  /**
+   * Creates a new system message from a string.
+   *
+   * @param message the first message.
+   */
+  @Tolerate
+  public OpenAiSystemMessage(@Nonnull final String message) {
+    content = new OpenAiMessageContent(List.of(new OpenAiTextItem(message)));
+  }
+
+  /**
+   * Add text to the message.
+   *
+   * @param message the text to add.
+   * @return the new message.
+   * @since 1.3.0
+   */
+  @Nonnull
+  public OpenAiSystemMessage withText(@Nonnull final String message) {
+    final var contentItems = new LinkedList<>(content.items());
+    contentItems.add(new OpenAiTextItem(message));
+    return new OpenAiSystemMessage(new OpenAiMessageContent(contentItems));
+  }
 
   /**
    * Converts the message to a serializable object.
    *
-   * @return the corresponding {@code ChatCompletionRequestSystemMessage} object.
+   * @return the corresponding serializable object.
    */
   @Nonnull
-  public ChatCompletionRequestSystemMessage createDTO() {
+  public ChatCompletionRequestSystemMessage createChatCompletionRequestMessage()
+      throws IllegalArgumentException {
+    final var itemList = this.content().items();
+    if (itemList.size() == 1 && itemList.get(0) instanceof OpenAiTextItem textItem) {
+      return new ChatCompletionRequestSystemMessage()
+          .role(ChatCompletionRequestSystemMessage.RoleEnum.fromValue(role()))
+          .content(ChatCompletionRequestSystemMessageContent.create(textItem.text()));
+    }
+
+    final var contentList = new LinkedList<ChatCompletionRequestSystemMessageContentPart>();
+    for (final OpenAiContentItem item : itemList) {
+      if (item instanceof OpenAiTextItem textItem) {
+        contentList.add(
+            new ChatCompletionRequestMessageContentPartText()
+                .type(ChatCompletionRequestMessageContentPartText.TypeEnum.TEXT)
+                .text(textItem.text()));
+      } else if (item instanceof OpenAiImageItem) {
+        throw new IllegalArgumentException("Image items are not yet supported in system messages");
+      }
+    }
     return new ChatCompletionRequestSystemMessage()
         .role(ChatCompletionRequestSystemMessage.RoleEnum.fromValue(role()))
-        .content(ChatCompletionRequestSystemMessageContent.create(content()));
+        .content(ChatCompletionRequestSystemMessageContent.create(contentList));
   }
 }

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiTextItem.java

@@ -0,0 +1,11 @@
+package com.sap.ai.sdk.foundationmodels.openai;
+
+import javax.annotation.Nonnull;
+
+/**
+ * Represents a text item in a {@link OpenAiMessageContent} object.
+ *
+ * @param text the text of the item
+ * @since 1.3.0
+ */
+public record OpenAiTextItem(@Nonnull String text) implements OpenAiContentItem {}