feat: 预设提示词的对话调用

backend/internal/llm/client.go

@@ -44,5 +44,27 @@ func (c *Client) Chat(ctx context.Context, messages []llms.MessageContent) (stri
     }
     log.Printf("[INFO] Chat completed successfully, choice length: %d", len(resp.Choices[0].Content))
 
+	return resp.Choices[0].Content, nil
+}
+
+// Client包含系统提示词的调用
+func (c *Client) ChatWithSystemPrompt(ctx context.Context, systemPrompt string, messages []llms.MessageContent) (string, error) {
+	// 构造系统提示词消息
+	systemMessage := llms.TextParts(llms.ChatMessageTypeSystem, systemPrompt)
+	
+	// 将系统提示词插入到消息列表头部
+	allMessages := append([]llms.MessageContent{systemMessage}, messages...)
+
+	resp, err := c.llm.GenerateContent(ctx, allMessages)
+	if err != nil {
+		log.Printf("[ERROR] GenerateContent with system prompt failed: %v", err)
+		return "", fmt.Errorf("generate content error: %w", err)
+	}
+	if resp == nil || len(resp.Choices) == 0 {
+		log.Printf("[WARN] Response with system prompt is empty or has no choices")
+		return "", fmt.Errorf("no content choices returned")
+	}
+	log.Printf("[INFO] Chat with system prompt completed successfully, choice length: %d", len(resp.Choices[0].Content))
+
 	return resp.Choices[0].Content, nil
 }

backend/internal/llm/client_test.go

@@ -91,4 +91,60 @@ func TestClient_Chat(t *testing.T) {
 	}
 
 	log.Printf("[INFO] TestClient_Chat completed successfully")
+}
+
+func TestClient_ChatWithSystemPrompt(t *testing.T) {
+	// 1. 加载配置
+	cfg, err := config.Load()
+	if err != nil {
+		log.Printf("[WARN] config.Load() returned error: %v, using default config", err)
+	} else {
+		log.Printf("[INFO] config loaded successfully, LLM config: %+v", cfg.LLM)
+	}
+
+	// 2. 创建客户端
+	client, err := NewClient(cfg.LLM)
+	if err != nil {
+		log.Printf("[ERROR] NewClient() returned unexpected error: %v", err)
+		t.Fatalf("NewClient() returned unexpected error: %v", err)
+	}
+	log.Printf("[INFO] NewClient() succeeded, client created")
+
+	// 3. 构造系统提示词与消息列表
+	systemPrompt := "你是一个专业的知识图谱助手，请用简洁的中文回答问题。"
+	messages := []llms.MessageContent{
+		{
+			Role: "human",
+			Parts: []llms.ContentPart{
+				llms.TextContent{Text: "请简要介绍一下知识图谱的概念"},
+			},
+		},
+	}
+	log.Printf("[INFO] preparing chat with system prompt request, system prompt: %q, messages count: %d, content: %q", systemPrompt, len(messages), messages[0].Parts[0].(llms.TextContent).Text)
+
+	// 4. 调用被测方法
+	log.Printf("[INFO] calling client.ChatWithSystemPrompt()...")
+	got, err := client.ChatWithSystemPrompt(context.Background(), systemPrompt, messages)
+	
+	// 5. 校验结果
+	if err != nil {
+		log.Printf("[ERROR] ChatWithSystemPrompt() returned error: %v", err)
+		t.Errorf("ChatWithSystemPrompt() error = %v, want nil", err)
+		return
+	}
+	log.Printf("[INFO] client.ChatWithSystemPrompt() call completed without error")
+
+	if len(got) == 0 {
+		log.Printf("[ERROR] ChatWithSystemPrompt() returned empty response, got: %v", got)
+		t.Errorf("ChatWithSystemPrompt() returned empty response, want non-empty")
+	} else {
+		// 截取前100个字符打印，防止LLM返回内容过长刷屏，同时方便调试确认内容
+		preview := got
+		if len(preview) > 100 {
+			preview = preview[:100] + "..."
+		}
+		log.Printf("[INFO] ChatWithSystemPrompt() response validation passed, response preview: %q", preview)
+	}
+
+	log.Printf("[INFO] TestClient_ChatWithSystemPrompt completed successfully")
 }