if (Constants.NONE.equals(llmType)) {
            throw new LlmException("LLM client is not available");
        }
        if (!isRagChatEnabled()) {
            throw new LlmException("LLM client is not available");
        }
        final LlmClient client = getClient();
        if (client == null || !client.isAvailable()) {
            throw new LlmException("LLM client is not available");
        }
        return client;

            return LlmException.ERROR_AUTH;
        }
        if (statusCode == 404) {
            return LlmException.ERROR_MODEL_NOT_FOUND;
        }
        if (statusCode == 408) {
            return LlmException.ERROR_TIMEOUT;
        }
        if (statusCode == 502 || statusCode == 503) {
            return LlmException.ERROR_SERVICE_UNAVAILABLE;
        }
        return LlmException.ERROR_UNKNOWN;
    }

    /**
     * Performs a chat completion request.
     *
     * @param request the chat request containing messages and parameters
     * @return the chat response from the LLM
     * @throws LlmException if an error occurs during the request
     */
    LlmChatResponse chat(LlmChatRequest request);

    /**
     * Performs a streaming chat completion request.

                logger.debug("SSE stream completed. sessionId={}, hasHtmlContent={}", result.getSessionId(), htmlContent != null);
            }

        } catch (final LlmException e) {
            // LlmException from streamChatEnhanced already sent onError via callback - avoid double-send
            logger.warn("LLM error during stream request. sessionId={}, errorCode={}, message={}", sessionId, e.getErrorCode(),

import org.codelibs.fess.llm.IntentDetectionResult;
import org.codelibs.fess.llm.LlmChatResponse;
import org.codelibs.fess.llm.LlmClient;
import org.codelibs.fess.llm.LlmClientManager;
import org.codelibs.fess.llm.LlmException;
import org.codelibs.fess.llm.LlmMessage;
import org.codelibs.fess.llm.LlmStreamCallback;
import org.codelibs.fess.llm.RelevanceEvaluationResult;
import org.codelibs.fess.mylasta.direction.FessConfig;

        assertEquals("original query", result);
    }

    @Test
    public void test_regenerateQuery_exception_returnsFailedQuery() {
        client.setChatResponse(null); // causes LlmException

        final String result = client.regenerateQuery("test question", "original query", "no_results", Collections.emptyList());

        assertEquals("original query", result);
    }

    @Test