back/Contracts/Repositories/ISpendingGroupRepo.cs

@@ -6,6 +6,7 @@ namespace Contracts.Repositories;
 public interface ISpendingGroupRepo
 {
     Task<SpendingGroupDto?> Get(SpendingGroupSearch search);
+    Task<SpendingGroupDto?> GetByPlan(SpendingPlanSearch search);
     Task<IEnumerable<SpendingGroupDto>> GetList(SpendingGroupSearch? search = null);
     Task<SpendingGroupDto> Create(SpendingGroupDto spendingGroup);
     Task<SpendingGroupDto?> Delete(SpendingGroupSearch search);

back/Contracts/Services/IReportOffsetFromPlanService.cs

@@ -0,0 +1,9 @@
+using Contracts.SearchModels;
+using Contracts.ViewModels;
+
+namespace Contracts.Services;
+
+public interface IReportOffsetFromPlanService
+{
+    public Task<SpendingGroupViewModel> GetReportData(SpendingPlanSearch search);
+}

back/Infrastructure/Repositories/SpendingGroupRepo.cs

@@ -54,6 +54,30 @@ public class SpendingGroupRepo : ISpendingGroupRepo
         return group?.ToDto();
     }
 
+    public async Task<SpendingGroupDto?> GetByPlan(SpendingPlanSearch search)
+    {
+        using var context = _factory.CreateDbContext();
+        var plan = await context.SpendingPlans
+            .FirstOrDefaultAsync(x => x.Id == search.Id);
+
+        if (plan == null)
+        {
+            return null;
+        }
+
+        var group = await context.SpendingGroups
+            .Where(x => x.Id == plan.SpendingGroupId)
+            .Include(x => x.ChangeRecords != null 
+                ? x.ChangeRecords
+                    .Where(cg => cg.ChangedAt >= plan.StartAt && cg.ChangedAt <= plan.EndAt)
+                    .OrderBy(cg => cg.ChangedAt)
+                : null)
+            .LastAsync();
+        group.SpendingPlans = [plan];
+
+        return group.ToDto();
+    }
+
     public async Task<IEnumerable<SpendingGroupDto>> GetList(SpendingGroupSearch? search = null)
     {
         using var context = _factory.CreateDbContext();

back/Services/Reports/ReportOffsetFromPlanService.cs

@@ -0,0 +1,32 @@
+using Contracts.Mappers;
+using Contracts.Repositories;
+using Contracts.SearchModels;
+using Contracts.Services;
+using Contracts.ViewModels;
+using Services.Support.Exceptions;
+
+namespace Services.Reports;
+
+public class ReportOffsetFromPlanService : IReportOffsetFromPlanService
+{
+    private readonly ISpendingGroupRepo _spendingGroupRepo;
+
+    public ReportOffsetFromPlanService(ISpendingGroupRepo spendingGroupRepo)
+    {
+        _spendingGroupRepo = spendingGroupRepo;
+    }
+
+    public async Task<SpendingGroupViewModel> GetReportData(SpendingPlanSearch search)
+    {
+        var group = await _spendingGroupRepo.GetByPlan(search);
+        if (group == null)
+        {
+            throw new EntityNotFoundException("Не удалось найти группу по такому плану");
+        }
+        if (!group.ChangeRecords.Any())
+        {
+            throw new ReportDataNotFoundException("Данные об изменении баланса отсутствуют");
+        }
+        return group.ToView();
+    }
+}

back/Services/Support/Exceptions/ReportDataNotFoundException.cs

@@ -0,0 +1,10 @@
+namespace Services.Support.Exceptions;
+
+public class ReportDataNotFoundException : EntityNotFoundException
+{
+    public ReportDataNotFoundException(string message) 
+        : base(message) { }
+    public ReportDataNotFoundException(string message, Exception innerException) 
+        : base(message, innerException) { }
+    
+}