Improved ResponseChatBubble w/single item serialization

Author: folomeev

libai/src/main/java/ai/api/GsonFactory.java

@@ -196,7 +196,16 @@ public ResponseChatBubble deserialize(JsonElement json, Type typeOfT,
 
     @Override
     public JsonElement serialize(ResponseChatBubble src, Type typeOfSrc, JsonSerializationContext context) {
-      return SIMPLIFIED_GSON.toJsonTree(src, ResponseMessage.class);
+      JsonObject result = (JsonObject)SIMPLIFIED_GSON.toJsonTree(src, ResponseMessage.class);
+      JsonArray items = result.getAsJsonArray("items");
+      if ((items != null) && (items.size() == 1)) {
+        JsonObject item = (JsonObject)items.get(0);
+        result.add("textToSpeech", item.get("textToSpeech"));
+        result.add("ssml", item.get("ssml"));
+        result.add("displayText", item.get("displayText"));
+        result.remove("items");
+      }
+      return result;
     }
   }
 }

libai/src/test/java/ai/api/model/GoogleAssistantResponseMessagesTest.java

@@ -35,8 +35,8 @@ public class GoogleAssistantResponseMessagesTest {
 
   private final String TEST_CHAT_BUBBLE_SINGLE_ITEM = "{"
       + "\"customizeAudio\":true,"
-      + "\"textToSpeech\":\"hello\",\"ssml\":\"ssmlText\",\"displayText\":\"Hello\","
-      + "\"type\":\"simple_response\",\"platform\":\"google\""
+      + "\"type\":\"simple_response\",\"platform\":\"google\","
+      + "\"textToSpeech\":\"hello\",\"ssml\":\"ssmlText\",\"displayText\":\"Hello\""
       + "}";
 
   private final String TEST_BASIC_CARD = "{"
@@ -75,6 +75,20 @@ public class GoogleAssistantResponseMessagesTest {
       + "\"type\":\"link_out_chip\",\"platform\":\"google\""
       + "}";
 
+  @Test
+  public void testResponseChatBubbleSerialization() {
+    ResponseChatBubble chatBubble = new ResponseChatBubble();
+    chatBubble.setCustomizeAudio(true);
+    
+    ResponseChatBubble.Item item = new ResponseChatBubble.Item();
+    item.setTextToSpeech("hello");
+    item.setSsml("ssmlText");
+    item.setDisplayText("Hello");
+
+    chatBubble.setItems(Arrays.asList(item));
+    assertEquals(TEST_CHAT_BUBBLE_SINGLE_ITEM, gson.toJson(chatBubble));
+  }
+
   @Test
   public void testResponseChatBubbleDeserialization() {
     ResponseChatBubble chatBubble =