重构分类信息构建逻辑，提取为独立方法并优化代码结构

Service/SmartHandleService.cs

@@ -85,21 +85,8 @@ public class SmartHandleService(
                 }
             }
 
-            // 获取所有分类
-            var categories = await categoryRepository.GetAllAsync();
-
             // 构建分类信息
-            var categoryInfo = new StringBuilder();
+            var categoryInfo = await GetCategoryInfoAsync();
-            foreach (var type in new[] { 0, 1, 2 })
-            {
-                var typeName = GetTypeName((TransactionType)type);
-                categoryInfo.AppendLine($"{typeName}: ");
-                var categoriesOfType = categories.Where(c => (int)c.Type == type).ToList();
-                foreach (var category in categoriesOfType)
-                {
-                    categoryInfo.AppendLine($"- {category.Name}");
-                }
-            }
 
             // 构建账单分组信息
             var billsInfo = new StringBuilder();
@@ -257,6 +244,9 @@ public class SmartHandleService(
     {
         try
         {
+            // 构建分类信息
+            var categoryInfo = await GetCategoryInfoAsync();
+
             // 第一步：使用AI生成聚合SQL查询
             var now = DateTime.Now;
             var sqlPrompt = $$"""
@@ -313,6 +303,9 @@ public class SmartHandleService(
             }
             ```
 
+            【重要】请从以下分类列表中选择分类条件：
+            {{categoryInfo}}
+
             只返回SQL语句。
             """;
 
@@ -419,35 +412,6 @@ public class SmartHandleService(
         }
     }
 
-    /// <summary>
-    /// 查找匹配的右括号
-    /// </summary>
-    private static int FindMatchingBrace(string str, int startPos)
-    {
-        int braceCount = 0;
-        for (int i = startPos; i < str.Length; i++)
-        {
-            if (str[i] == '{') braceCount++;
-            else if (str[i] == '}')
-            {
-                braceCount--;
-                if (braceCount == 0) return i;
-            }
-        }
-        return -1;
-    }
-
-    private static string GetTypeName(TransactionType type)
-    {
-        return type switch
-        {
-            TransactionType.Expense => "支出",
-            TransactionType.Income => "收入",
-            TransactionType.None => "不计入收支",
-            _ => "未知"
-        };
-    }
-
     public async Task<TransactionParseResult?> ParseOneLineBillAsync(string text)
     {
         // 获取所有分类
@@ -507,6 +471,56 @@ public class SmartHandleService(
             return null;
         }
     }
+
+    /// <summary>
+    /// 查找匹配的右括号
+    /// </summary>
+    private static int FindMatchingBrace(string str, int startPos)
+    {
+        int braceCount = 0;
+        for (int i = startPos; i < str.Length; i++)
+        {
+            if (str[i] == '{') braceCount++;
+            else if (str[i] == '}')
+            {
+                braceCount--;
+                if (braceCount == 0) return i;
+            }
+        }
+        return -1;
+    }
+
+    private static string GetTypeName(TransactionType type)
+    {
+        return type switch
+        {
+            TransactionType.Expense => "支出",
+            TransactionType.Income => "收入",
+            TransactionType.None => "不计入收支",
+            _ => "未知"
+        };
+    }
+
+    private async Task<string> GetCategoryInfoAsync()
+    {
+        // 获取所有分类
+        var categories = await categoryRepository.GetAllAsync();
+
+        // 构建分类信息
+        var categoryInfo = new StringBuilder();
+        foreach (var type in new[] { 0, 1, 2 })
+        {
+            var typeName = GetTypeName((TransactionType)type);
+            categoryInfo.AppendLine($"{typeName}: ");
+            var categoriesOfType = categories.Where(c => (int)c.Type == type).ToList();
+            foreach (var category in categoriesOfType)
+            {
+                categoryInfo.AppendLine($"- {category.Name}");
+            }
+        }
+
+        return categoryInfo.ToString();
+    }
 }
 
 /// <summary>