back/Contracts/Repositories/IUserRepo.cs

@@ -8,5 +8,6 @@ public interface IUserRepo
     public Task<UserDto?> Get(UserSearch search);
     public Task<UserDto> Create(UserDto user);
     public Task<UserDto?> Update(UserDto user);
+    public Task<bool> ChangeBalance(UserSearch search, decimal amount);
     public Task<UserDto?> Delete(UserSearch search);
 }

back/Infrastructure/Repositories/UserRepo.cs

@@ -15,6 +15,25 @@ public class UserRepo : IUserRepo
         _factory = factory;
     }
 
+    public async Task<bool> ChangeBalance(UserSearch search, decimal amount)
+    {
+        using var context = _factory.CreateDbContext();
+
+        var user = await context.Users
+            .FirstOrDefaultAsync(x => x.Id == search.Id
+                || x.Name == search.Name);
+        
+        if (user == null)
+        {
+            return false;
+        }
+
+        user.Balance += amount;
+        context.Users.Update(user);
+        await context.SaveChangesAsync();
+        return true;
+    }
+
     public async Task<UserDto> Create(UserDto user)
     {
         using var context = _factory.CreateDbContext();

back/Services/Domain/ChangeRecordService.cs

@@ -10,16 +10,20 @@ namespace Services.Domain;
 public class ChangeRecordService : IChangeRecordService
 {
     private readonly IChangeRecordRepo _changeRecordRepo;
+    private readonly IUserRepo _userRepo;
 
-    public ChangeRecordService(IChangeRecordRepo changeRecordRepo) 
+    public ChangeRecordService(IChangeRecordRepo changeRecordRepo, IUserRepo userRepo)
     {
         _changeRecordRepo = changeRecordRepo;
+        _userRepo = userRepo;
     }
 
     public async Task<ChangeRecordViewModel> Create(ChangeRecordDto model)
     {
         var record = await _changeRecordRepo.Create(model);
 
+        await _userRepo.ChangeBalance(new() { Id = model.UserId }, model.Sum);
+
         return record.ToView();
     }
 
@@ -30,6 +34,8 @@ public class ChangeRecordService : IChangeRecordService
         {
             throw new EntryPointNotFoundException("При удалении не получилось найти запись измнения баланса");
         }
+        // Возвращает баланс обратно
+        await _userRepo.ChangeBalance(new() { Id = record.UserId }, -record.Sum);
         return record.ToView();
     }
 
@@ -47,6 +53,7 @@ public class ChangeRecordService : IChangeRecordService
         {
             throw new EntryPointNotFoundException("При изменении не получилось найти запись измнения баланса");
         }
+        await _userRepo.ChangeBalance(new() { Id = model.UserId }, model.Sum - record.Sum);
         return record.ToView();
     }
 }