Add user service

BTCPayServer/Services/UserService.cs

@@ -0,0 +1,44 @@
+using System.Linq;
+using System.Threading.Tasks;
+using BTCPayServer.Data;
+using BTCPayServer.Storage.Services;
+using BTCPayServer.Services.Stores;
+using Microsoft.AspNetCore.Identity;
+
+namespace BTCPayServer.Services
+{
+    public class UserService
+    {
+        private readonly UserManager<ApplicationUser> _userManager;
+        private readonly StoredFileRepository _storedFileRepository;
+        private readonly FileService _fileService;
+        private readonly StoreRepository _storeRepository;
+
+        public UserService(
+            UserManager<ApplicationUser> userManager,
+            StoredFileRepository storedFileRepository,
+            FileService fileService,
+            StoreRepository storeRepository
+        )
+        {
+            _userManager = userManager;
+            _storedFileRepository = storedFileRepository;
+            _fileService = fileService;
+            _storeRepository = storeRepository;
+        }
+
+        public async Task DeleteUserAndAssociatedData(ApplicationUser user) 
+        {
+            var userId = user.Id;
+            var files = await _storedFileRepository.GetFiles(new StoredFileRepository.FilesQuery()
+            {
+                UserIds = new[] { userId },
+            });
+
+            await Task.WhenAll(files.Select(file => _fileService.RemoveFile(file.Id, userId)));
+
+            await _userManager.DeleteAsync(user);
+            await _storeRepository.CleanUnreachableStores();
+        }
+    }
+}