feat: 添加存款分类设置功能，优化预算管理界面

WebApi/Controllers/BudgetController.cs

@@ -4,6 +4,7 @@
 [Route("api/[controller]/[action]")]
 public class BudgetController(
     IBudgetService budgetService,
+    IConfigService configService,
     ILogger<BudgetController> logger) : ControllerBase
 {
     /// <summary>
@@ -23,6 +24,10 @@ public class BudgetController(
                 dtos.Add(BudgetDto.FromEntity(budget, currentAmount, referenceDate));
             }
 
+            // 创造虚拟的存款预算
+            dtos.Add(await GetVirtualSavingsDtoAsync(BudgetPeriodType.Month, referenceDate));
+            dtos.Add(await GetVirtualSavingsDtoAsync(BudgetPeriodType.Year, referenceDate));
+
             return dtos.Ok();
         }
         catch (Exception ex)
@@ -40,6 +45,15 @@ public class BudgetController(
     {
         try
         {
+            if (id == -1)
+            {
+                return (await GetVirtualSavingsDtoAsync(BudgetPeriodType.Year, referenceDate)).Ok();
+            }
+            if (id == -2)
+            {
+                return (await GetVirtualSavingsDtoAsync(BudgetPeriodType.Month, referenceDate)).Ok();
+            }
+
             var budget = await budgetService.GetByIdAsync(id);
             if (budget == null) return "预算不存在".Fail<BudgetDto>();
 
@@ -147,6 +161,84 @@ public class BudgetController(
         }
     }
 
+    private async Task<BudgetDto> GetVirtualSavingsDtoAsync(BudgetPeriodType periodType, DateTime? referenceDate = null)
+    {
+        var allBudgets = await budgetService.GetAllAsync();
+        var date = referenceDate ?? DateTime.Now;
+
+        decimal incomeLimitAtPeriod = 0;
+        decimal expenseLimitAtPeriod = 0;
+
+        var savingsCategories = await configService.GetConfigByKeyAsync<string>("SavingsCategories") ?? string.Empty;
+        var selectedCategoryList = savingsCategories.Split(',', StringSplitOptions.RemoveEmptyEntries);
+
+        foreach (var b in allBudgets)
+        {
+            if (b.IsStopped || b.Category == BudgetCategory.Savings) continue;
+
+            // 如果设置了存款分类，并且预算有指定分类，则只统计相关的预算
+            if (selectedCategoryList.Length > 0)
+            {
+                var budgetCategories = b.SelectedCategories.Split(',', StringSplitOptions.RemoveEmptyEntries);
+                if (budgetCategories.Length > 0 && !budgetCategories.Intersect(selectedCategoryList).Any())
+                {
+                    continue;
+                }
+            }
+
+            // 折算系数：根据当前请求的 periodType (Year 或 Month)，将预算 b 的 Limit 折算过来
+            decimal factor = 1.0m;
+
+            if (periodType == BudgetPeriodType.Year)
+            {
+                factor = b.Type switch
+                {
+                    BudgetPeriodType.Month => 12,
+                    BudgetPeriodType.Week => 52,
+                    BudgetPeriodType.Year => 1,
+                    _ => 0
+                };
+            }
+            else if (periodType == BudgetPeriodType.Month)
+            {
+                factor = b.Type switch
+                {
+                    BudgetPeriodType.Month => 1,
+                    BudgetPeriodType.Week => 52m / 12m,
+                    BudgetPeriodType.Year => 1m / 12m,
+                    _ => 0
+                };
+            }
+            else
+            {
+                factor = 0; // 其他周期暂不计算虚拟存款
+            }
+
+            if (b.Category == BudgetCategory.Income) incomeLimitAtPeriod += b.Limit * factor;
+            else if (b.Category == BudgetCategory.Expense) expenseLimitAtPeriod += b.Limit * factor;
+        }
+
+        var virtualBudget = new BudgetRecord
+        {
+            Id = periodType == BudgetPeriodType.Year ? -1 : -2,
+            Name = periodType == BudgetPeriodType.Year ? "年度存款" : "月度存款",
+            Category = BudgetCategory.Savings,
+            Type = periodType,
+            Limit = incomeLimitAtPeriod - expenseLimitAtPeriod,
+            StartDate = periodType == BudgetPeriodType.Year ? new DateTime(date.Year, 1, 1) : new DateTime(date.Year, date.Month, 1),
+            SelectedCategories = savingsCategories
+        };
+
+        // 计算实际发生的 收入 - 支出
+        var incomeHelper = new BudgetRecord { Category = BudgetCategory.Income, Type = periodType, StartDate = virtualBudget.StartDate, SelectedCategories = savingsCategories };
+        var expenseHelper = new BudgetRecord { Category = BudgetCategory.Expense, Type = periodType, StartDate = virtualBudget.StartDate, SelectedCategories = savingsCategories };
+
+        var actualIncome = await budgetService.CalculateCurrentAmountAsync(incomeHelper, date);
+        var actualExpense = await budgetService.CalculateCurrentAmountAsync(expenseHelper, date);
+
+        return BudgetDto.FromEntity(virtualBudget, actualIncome - actualExpense, date);
+    }
+
     private async Task<string> ValidateBudgetSelectedCategoriesAsync(BudgetRecord record)
     {
         var allBudgets = await budgetService.GetAllAsync();