UPDATE 05-Nov

src/main/java/com/example/mapper/messagefilter/ConversationContextMapper.java

@@ -21,6 +21,8 @@ public class ConversationContextMapper {
     @Value("${conversation.context.days.limit:30}")
     private int daysLimit;
 
+    private static final int MAX_HISTORY_BYTES = 50 * 1024; // 50 KB
+    
     public String toText(ConversationSessionDTO session, List<ConversationMessageDTO> messages) {
         if (messages == null || messages.isEmpty()) {
             return "";
@@ -41,7 +43,7 @@ public class ConversationContextMapper {
                 .limit(messageLimit)
                 .sorted(Comparator.comparing(ConversationMessageDTO::timestamp))
                 .collect(Collectors.toList());
-        return toTextFromMessages(recentEntries);
+        return toTextWithTruncation(recentEntries);
     }
 
     public String toTextFromMessages(List<ConversationMessageDTO> messages) {
@@ -50,6 +52,27 @@ public class ConversationContextMapper {
                 .collect(Collectors.joining("\n"));
     }
 
+    public String toTextWithTruncation(List<ConversationMessageDTO> messages) {
+        if (messages == null || messages.isEmpty()) {
+            return "";
+        }
+
+        StringBuilder textBlock = new StringBuilder();
+        List<String> formattedMessages = messages.stream()
+                .map(this::formatEntry)
+                .collect(Collectors.toList());
+
+        for (int i = formattedMessages.size() - 1; i >= 0; i--) {
+            String message = formattedMessages.get(i) + "\n";
+            if (textBlock.toString().getBytes(java.nio.charset.StandardCharsets.UTF_8).length + message.getBytes(java.nio.charset.StandardCharsets.UTF_8).length > MAX_HISTORY_BYTES) {
+                break;
+            }
+            textBlock.insert(0, message);
+        }
+
+        return textBlock.toString().trim();
+    }
+
     private String formatEntry(ConversationMessageDTO entry) {
         String prefix = "User: ";
 
@@ -70,10 +93,6 @@ public class ConversationContextMapper {
 
         String text = prefix + entry.text();
 
-        if (entry.parameters() != null && !entry.parameters().isEmpty()) {
-            text += " " + entry.parameters().toString();
-        }
-
         if (entry.type() == MessageType.AGENT) {
             text = cleanAgentMessage(text);
         }

src/test/java/com/example/mapper/messagefilter/ConversationContextMapperTest.java

@@ -1,8 +1,15 @@
 package com.example.mapper.messagefilter;
 
+import com.example.dto.dialogflow.conversation.ConversationMessageDTO;
+import com.example.dto.dialogflow.conversation.MessageType;
 import org.junit.jupiter.api.Test;
 import java.lang.reflect.Method;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class ConversationContextMapperTest {
 
@@ -91,4 +98,24 @@ public class ConversationContextMapperTest {
         String result = (String) method.invoke(mapper, input);
         assertEquals(expected, result);
     }
+
+    @Test
+    public void testToTextWithTruncation() {
+        ConversationContextMapper mapper = new ConversationContextMapper();
+        List<ConversationMessageDTO> messages = new ArrayList<>();
+        for (int i = 0; i < 1000; i++) {
+            messages.add(createMessage("This is message " + i, MessageType.USER));
+        }
+        for (int i = 1000; i < 2000; i++) {
+            messages.add(createMessage("This is message " + i, MessageType.AGENT));
+        }
+
+        String result = mapper.toTextWithTruncation(messages);
+        assertTrue(result.length() > 0);
+        assertTrue(result.getBytes(java.nio.charset.StandardCharsets.UTF_8).length <= 50 * 1024);
+    }
+
+    private ConversationMessageDTO createMessage(String text, MessageType type) {
+        return new ConversationMessageDTO(type, Instant.now(), text, null, null);
+    }
 }