feat: 添加 AI 记账功能，包括 API 处理器和核心服务逻辑。

internal/service/ai_bookkeeping_service.go

@@ -494,6 +494,103 @@ func (s *LLMService) parseIntentSimple(text string) (*AITransactionParams, strin
 	return params, message, nil
 }
 
+// GenerateReport generates a report based on the provided prompt using LLM
+func (s *LLMService) GenerateReport(ctx context.Context, prompt string) (string, error) {
+	if s.config.OpenAIAPIKey == "" || s.config.OpenAIBaseURL == "" {
+		return "", errors.New("OpenAI API not configured")
+	}
+
+	messages := []ChatMessage{
+		{
+			Role:    "user",
+			Content: prompt,
+		},
+	}
+
+	reqBody := ChatCompletionRequest{
+		Model:       s.config.ChatModel,
+		Messages:    messages,
+		Temperature: 0.7, // Higher temperature for creative insights
+	}
+
+	jsonBody, err := json.Marshal(reqBody)
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal request: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "POST", s.config.OpenAIBaseURL+"/chat/completions", bytes.NewReader(jsonBody))
+	if err != nil {
+		return "", fmt.Errorf("failed to create request: %w", err)
+	}
+
+	req.Header.Set("Authorization", "Bearer "+s.config.OpenAIAPIKey)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := s.httpClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("generate report request failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(resp.Body)
+		return "", fmt.Errorf("generate report failed with status %d: %s", resp.StatusCode, string(body))
+	}
+
+	var chatResp ChatCompletionResponse
+	if err := json.NewDecoder(resp.Body).Decode(&chatResp); err != nil {
+		return "", fmt.Errorf("failed to decode response: %w", err)
+	}
+
+	if len(chatResp.Choices) == 0 {
+		return "", errors.New("no response from AI")
+	}
+
+	return chatResp.Choices[0].Message.Content, nil
+}
+
+// GenerateDailyInsight generates a daily insight report
+func (s *AIBookkeepingService) GenerateDailyInsight(ctx context.Context, userID uint, data map[string]interface{}) (string, error) {
+	// 1. Serialize context data to JSON for the prompt
+	dataBytes, err := json.MarshalIndent(data, "", "  ")
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal context data: %w", err)
+	}
+
+	// 2. Construct Prompt
+    prompt := fmt.Sprintf(`[SYSTEM: You are a personal financial analyst. Your task is to provide a brief, warm, and actionable daily financial insight based on the provided data.]
+
+DATA:
+%s
+
+TASK:
+Output a JSON object with exactly two fields: "spending" and "budget".
+1. "spending": A comment on today's spending (max 40 chars). Warm tone. Mention weekday if relevant. Praise streaks.
+2. "budget": Actionable advice on budget status (max 40 chars).
+
+OUTPUT FORMAT (JSON ONLY, NO MARKDOWN):
+{"spending": "...", "budget": "..."}`, string(dataBytes))
+
+	// 3. Call LLM
+	report, err := s.llmService.GenerateReport(ctx, prompt)
+	if err != nil {
+		return "", err
+	}
+    
+    // Clean up markdown if present
+    report = strings.TrimSpace(report)
+    if strings.HasPrefix(report, "```") {
+        if idx := strings.Index(report, "\n"); idx != -1 {
+            report = report[idx+1:]
+        }
+        if idx := strings.LastIndex(report, "```"); idx != -1 {
+            report = report[:idx]
+        }
+    }
+    
+	return strings.TrimSpace(report), nil
+}
+
 // MapAccountName maps natural language account name to account ID
 func (s *LLMService) MapAccountName(ctx context.Context, name string, userID uint) (*uint, string, error) {
 	if name == "" {