[fix] 채팅 - LLM 서버 연결 및 오류 수정

MathCaptain/weakness/src/main/java/MathCaptain/weakness/domain/Chat/controller/ChatController.java

@@ -4,8 +4,6 @@
 import MathCaptain.weakness.domain.Chat.dto.request.LLMRequest;
 import MathCaptain.weakness.domain.Chat.dto.response.ChatResponse;
 import MathCaptain.weakness.domain.Chat.service.ChatService;
-import MathCaptain.weakness.domain.User.entity.Users;
-import MathCaptain.weakness.global.annotation.LoginUser;
 import lombok.RequiredArgsConstructor;
 import org.springframework.messaging.handler.annotation.MessageMapping;
 import org.springframework.messaging.simp.SimpMessagingTemplate;
@@ -41,9 +39,7 @@ public void handleChat(ChatRequest request) {
         template.convertAndSend("/sub/" + request.getUserId(), chatResponse);
 
         // 2) LLM 호출 & 응답 저장 + 브로드캐스트 (동기 방식)
-        List<ChatResponse> llmResponses = chatService.askAI(request);
-        llmResponses.forEach(aiResp ->
-            template.convertAndSend("/sub/" + request.getUserId(), aiResp)
-        );
+        ChatResponse llmResponse = chatService.askAI(request);
+        template.convertAndSend("/sub/" + request.getUserId(), llmResponse);
     }
 }

MathCaptain/weakness/src/main/java/MathCaptain/weakness/domain/Chat/dto/request/Prompt.java

@@ -18,7 +18,7 @@ public class Prompt {
     private List<ChatResponse> history;
 
     private Prompt(Long userId, String message, List<ChatResponse> history) {
-        this.template = "다음 내용을 참고하여 답변해줘";
+        this.template = "질문의 내용에 답변을 할 때 사용자의 활동기록과 문서에서 검색된 내용이 필요하면 참고해서 답변해줘";
         this.inputs = Map.of(
                 "user_id", userId.toString(),
                 "user_question", message

MathCaptain/weakness/src/main/java/MathCaptain/weakness/domain/Chat/entity/Chat.java

@@ -29,6 +29,7 @@ public class Chat {
     @Enumerated(EnumType.STRING)
     private ChatRole role;
 
+    @Column(columnDefinition = "LONGTEXT")
     private String message;
 
     @CreatedDate

MathCaptain/weakness/src/main/java/MathCaptain/weakness/domain/Chat/service/ChatService.java

@@ -15,7 +15,7 @@
 @Slf4j
 @Service
 @RequiredArgsConstructor
-@Transactional(readOnly = true)
+@Transactional
 public class ChatService {
 
     private final ChatRepository chatRepository;
@@ -28,15 +28,13 @@ public ChatResponse saveUserMessage(ChatRequest request) {
         return ChatResponse.of(saved);
     }
 
-    public List<ChatResponse> askAI(ChatRequest request) {
+    public ChatResponse askAI(ChatRequest request) {
         List<ChatResponse> history = chatRepository.findAllByUserIdOrderBySendTimeAsc(request.getUserId()).stream()
                 .map(ChatResponse::of)
                 .toList();
 
-        List<Chat> aiChats = llm.call(history, request);
-        return aiChats.stream()
-                      .map(this::storeAndTransform)
-                      .toList();
+        Chat aiChats = llm.call(history, request);
+        return storeAndTransform(aiChats);
     }
 
     @Transactional

MathCaptain/weakness/src/main/java/MathCaptain/weakness/domain/Chat/service/LLMClient.java

@@ -8,6 +8,7 @@
 import groovy.util.logging.Slf4j;
 import lombok.RequiredArgsConstructor;
 import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Component;
 import org.springframework.web.client.HttpClientErrorException;
@@ -31,33 +32,31 @@ public class LLMClient {
     @Value("${llm.server.url}")
     private String baseUrl;
 
-    public List<Chat> call(List<ChatResponse> history, ChatRequest request) {
+    public Chat call(List<ChatResponse> history, ChatRequest request) {
         try {
             LLMRequest llmRequest = LLMRequest.of(request, history);
 
-            ResponseEntity<ChatResponse[]> response = restTemplate.postForEntity(
+            ResponseEntity<ChatResponse> response = restTemplate.postForEntity(
                     // TODO : 엔드포인트 수정
-                    baseUrl + "/v1/chat",
+                    baseUrl + "/mcp/query",
                     llmRequest,
                     // 응답을 ChatResponse[] (배열)로 역직렬화 (수정 필요)
-                    ChatResponse[].class
+                    ChatResponse.class
             );
 
-            ChatResponse[] body = response.getBody();
+            ChatResponse body = response.getBody();
             if (body == null) {
-                return Collections.emptyList();
+                throw new HttpServerErrorException(HttpStatus.NOT_ACCEPTABLE, "LLM이 응답하지 않습니다");
             }
-            return Arrays.stream(body)
-                    .map(Chat::of)
-                    .collect(Collectors.toList());
+            return Chat.of(body);
 
         } catch (ResourceAccessException timeoutEx) {
             log.error("LLM 서버 응답 지연", timeoutEx);
-            return List.of();
+            throw new ResourceAccessException("LLM 서버 응답 지연");
         } catch (HttpClientErrorException | HttpServerErrorException httpEx) {
             // 4XX/5XX 응답
             log.error("LLM 호출 실패: {}", httpEx.getStatusCode(), httpEx);
-            return List.of();
+            throw new HttpClientErrorException(HttpStatus.NOT_ACCEPTABLE, "LLM 호출 실패");
         }
     }
 }

MathCaptain/weakness/src/main/java/MathCaptain/weakness/domain/common/enums/ChatRole.java

@@ -1,6 +1,13 @@
 package MathCaptain.weakness.domain.common.enums;
 
+import com.fasterxml.jackson.annotation.JsonCreator;
+
 public enum ChatRole {
     USER,
-    ASSISTANT
+    ASSISTANT;
+
+    @JsonCreator
+    public static ChatRole fromValue(String value) {
+        return ChatRole.valueOf(value.toUpperCase());
+    }
 }