PR N: polish pass — ClassIds static, drop loaded flag, mandator from config

Three long-noted rough edges from the original analysis, each a
one-line touch:

- ClassIds becomes static class (was instantiable).
- Home.razor.cs drops the `loaded` bool guard (Blazor already runs
  OnInitializedAsync exactly once per component instance).
- Move the "Claudio Schaad" mandator default out of SettingsService
  into SettingsDataset.DefaultMandator, plumbed through
  appsettings.Development.json.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

IMPROVEMENT_PLAN.md

@@ -103,3 +103,10 @@ Analysis and phased plan produced 2026-07-02. See conversation history for full
 - **PR F** — Phase 3 item 21: precomputed dictionaries in `ViewService` to eliminate O(N·M) `Single(...)` scans and per-account transaction filtering.
 - **Item 19 (async I/O)** — deferred. After PR D, each XML file is loaded at most once per SignalR circuit, and this app is single-user local Blazor Server. Converting every repository/service method to async would touch ~40 files for negligible user-visible benefit and real regression risk. Revisit if the app is ever hosted for multiple concurrent users.
 - **PR G** — Phase 4 items 23 + 24: `Schaad.Accounting.Tests` xUnit + NSubstitute + Shouldly project. Adopts the `xxxTestShould.DoThisWhenThat` naming convention with Shouldly assertions (no xUnit `Assert.*`). Covers `ViewService`, `TransactionRepository`, `Formatting`, `RepositoryCache`, `AccountRepository`, `ChartService`, and `FileService.GetTransactionListCsv` — 38 tests locking in the earlier PRs' behavior. Note: originally shipped as three separate commits (initial project, expanded coverage, Shouldly + naming conversion) and later squashed into one commit at the user's request.
+- **PR H** — Phase 2 item 18 (first slice): add `ILogger<FileService>` to `FileService.ImportAccountStatementFile` so bank-statement imports emit `Information` for the file being processed and each account's import count, `Warning` when an account is skipped because it belongs to a different mandator, and `Error` when the vendor parser reports a failure. Rest of the logging (BaseRepository save failures, MatchOpenBankTransactions summary) tracked as a follow-up because it requires threading loggers through all seven repositories.
+- **PR I** — Phase 2 item 12: move the service interfaces (`IViewService`, `IFileService`, `IChartService`) from `Schaad.Accounting.Common` into `Schaad.Accounting.Services/Interfaces/`. Namespaces are unchanged (`Schaad.Accounting.Interfaces`), so no consumer needs a `using` update. Drops the `Schaad.Finance.Api` `<Reference>` from `Common.csproj` — Common is now vendor-free and matches its documented role as the "shared models, DTOs, interfaces" layer.
+- **PR J** — Phase 2 item 18 (second slice): thread `ILogger<T>` through `BaseRepository` and every concrete repository so `BaseRepository.Save`'s catch block logs the failing file path and exception before rethrowing (previously the exception's origin was silently swallowed and only the stack trace at the callsite survived). Pulls `Microsoft.Extensions.Logging.Abstractions` into the Db project. `TransactionRepositoryTestShould` and `AccountRepositoryTestShould` use `NullLogger<T>.Instance`. Remaining item 18 work (MatchOpenBankTransactions match-count summary in `ViewService`) still open.
+- **PR K** — Phase 5 item 27: introduce `IFxConverter.ConvertToChf(amount, fromCurrency)` and its `FxConverter` implementation. The vendor `IFxService` and the FixerIo API key are now hidden inside `FxConverter`; callers stop threading the API key through every method call. `ViewService` drops both `IFxService` and `ISettingsService` from its constructor and takes `IFxConverter` instead. Simplifies `GetAccountViewList` (no more per-call `settingsService.GetSettings()` reads) and `GetBalanceSheetView`. Two-test `FxConverterTestShould` locks in the target-currency and API-key routing.
+- **PR L** — Phase 2 item 10: drop the hand-rolled `Copy(target)` methods from `Account`, `BookingRule`, `BookingText`, `SubClass`, and `SplitPredefinition`; keep only a `Transaction.Clone()` for defensive-copy needs in `GetTransaction` / `ViewService.WithDisplaySign`. Every `SaveXxx` now uses `FindIndex` → in-place replace (or `Add` for new entries), moving the two "hidden" defaults (`Account.Currency = "CHF"` when unset, `Transaction.BookingDate = ValueDate` when unset) into the corresponding `SaveXxx` method where they belong. Fixes a pre-existing bug: `Transaction.Copy` never copied `RelatedParty`, so update-saves silently dropped it. Added `PreserveRelatedPartyWhenRoundTrippingTransaction` and `DefaultBookingDateToValueDateWhenBookingDateIsUnset` as regression tests. 42 tests total.
+- **PR M** — Phase 2 item 18 (final slice): add `ILogger<ViewService>` and log a match-count summary from `MatchOpenBankTransactions` (`"Matched {Matched} of {Total} open bank transactions"`). Completes item 18 — statement imports (PR H), repository save failures (PR J), and match runs now all emit structured logs. Also removes a dead `ISettingsService` injection from `Home.razor.cs` (declared with `[Inject]` but never used anywhere in the file).
+- **PR N** — Small polish pass covering three long-noted rough edges from the original analysis: `ClassIds` becomes a `static class` (was instantiable); `Home.razor.cs` loses the redundant `loaded` guard in `OnInitializedAsync` (Blazor already runs that lifecycle hook once per component instance); the hardcoded `mandator = "Claudio Schaad"` in `SettingsService` moves to a `DefaultMandator` field on `SettingsDataset`, plumbed through `appsettings.Development.json`.

Schaad.Accounting.Common/ClassIds.cs

@@ -1,6 +1,6 @@
 namespace Schaad.Accounting
 {
-    public class ClassIds
+    public static class ClassIds
     {
         public const int Activa = 1;
         public const int Passiva = 2;

Schaad.Accounting.Common/Datasets/SettingsDataset.cs

@@ -5,5 +5,10 @@
         public string DataPath { get; set; }
 
         public string FixerIoApiKey { get; set; }
+
+        /// <summary>
+        /// Mandator selected when the app starts. Users can switch via the header dropdown.
+        /// </summary>
+        public string DefaultMandator { get; set; } = "Claudio Schaad";
     }
 }

Schaad.Accounting.Common/Models/Account.cs

@@ -59,19 +59,5 @@ namespace Schaad.Accounting.Models
         {
             get { return string.IsNullOrEmpty(Currency) == false && Currency != "CHF"; }
         }
-
-        /// <summary>
-        /// Makes a copy
-        /// </summary>
-        public void Copy(Account target)
-        {
-            target.LastBankBalance = LastBankBalance;
-            target.StartBalance = StartBalance;
-            target.BankAccountNumber = BankAccountNumber;
-            target.Currency = string.IsNullOrEmpty(Currency) ? "CHF" : Currency;
-            target.Id = Id;
-            target.Name = Name;
-            target.Number = Number;
-        }
     }
 }

Schaad.Accounting.Common/Models/BookingRule.cs

@@ -20,18 +20,5 @@ namespace Schaad.Accounting.Models
         [Display(Name = "Konto")]
         [Required]
         public string AccountId { get; set; }
-
-
-        /// <summary>
-        /// Makes a copy
-        /// </summary>
-        public void Copy(BookingRule target)
-        {
-            target.LookupText = LookupText;
-            target.LookupValue = LookupValue;
-            target.BookingText = BookingText;
-            target.Id = Id;
-            target.AccountId = AccountId;
-        }
     }
 }

Schaad.Accounting.Common/Models/BookingText.cs

@@ -10,14 +10,5 @@ namespace Schaad.Accounting.Models
         [Required]
         [MinLength(3)]
         public string Text { get; set; }
-
-        /// <summary>
-        /// Makes a copy
-        /// </summary>
-        public void Copy(BookingText target)
-        {
-            target.Id = Id;
-            target.Text = Text;
-        }
     }
 }

Schaad.Accounting.Common/Models/SplitPredefinition.cs

@@ -9,17 +9,5 @@
         public decimal BookingValue { get; set; }
 
         public string AccountId { get; set; }
-
-
-        /// <summary>
-        /// Makes a copy
-        /// </summary>
-        public void Copy(SplitPredefinition target)
-        {
-            target.BookingText = BookingText;
-            target.BookingValue = BookingValue;
-            target.Id = Id;
-            target.AccountId = AccountId;
-        }
     }
 }

Schaad.Accounting.Common/Models/SubClass.cs

@@ -14,15 +14,5 @@ namespace Schaad.Accounting.Models
         [Required]
         [MinLength(3)]
         public string Name { get; set; }
-
-        /// <summary>
-        /// Makes a copy
-        /// </summary>
-        public void Copy(SubClass target)
-        {
-            target.Id = Id;
-            target.Name = Name;
-            target.Number = Number;
-        }
     }
 }

Schaad.Accounting.Common/Models/Transaction.cs

@@ -74,20 +74,22 @@ namespace Schaad.Accounting.Models
         }
 
         /// <summary>
-        /// Makes a copy
+        /// Returns a shallow independent copy — used to hand out defensive copies
+        /// (e.g. from repository reads) without exposing the caller to later mutation.
         /// </summary>
-        public void Copy(Transaction target)
+        public Transaction Clone() => new()
         {
-            target.BankTransactionId = BankTransactionId;
+            Id = Id,
-            target.BankTransactionText = BankTransactionText;
+            BankTransactionId = BankTransactionId,
-            target.Id = Id;
+            BankTransactionText = BankTransactionText,
-            target.OriginAccountId = OriginAccountId;
+            RelatedParty = RelatedParty,
-            target.TargetAccountId = TargetAccountId;
+            OriginAccountId = OriginAccountId,
-            target.Text = Text;
+            TargetAccountId = TargetAccountId,
-            target.Value = Value;
+            Text = Text,
-            target.ValueDate = ValueDate;
+            Value = Value,
-            target.BookingDate = BookingDate > DateTime.MinValue ? BookingDate : ValueDate;
+            ValueDate = ValueDate,
-            target.FxRate = FxRate;
+            BookingDate = BookingDate,
-        }
+            FxRate = FxRate
+        };
     }
 }

Schaad.Accounting.Common/Schaad.Accounting.Common.csproj

@@ -4,9 +4,4 @@
     <TargetFramework>net9.0</TargetFramework>
     <RootNamespace>Schaad.Accounting</RootNamespace>
   </PropertyGroup>
-  <ItemGroup>
-    <Reference Include="Schaad.Finance.Api">
-      <HintPath>..\dlls\Schaad.Finance.Api.dll</HintPath>
-    </Reference>
-  </ItemGroup>
 </Project>

Schaad.Accounting.Db/Repositories/AccountRepository.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
 
@@ -11,8 +12,8 @@ namespace Schaad.Accounting.Repositories
     {
         private readonly string ACCOUNTS = "Accounts.xml";
 
-        public AccountRepository(ISettingsService settingsService, RepositoryCache cache)
+        public AccountRepository(ISettingsService settingsService, RepositoryCache cache, ILogger<AccountRepository> logger)
-            : base(settingsService, cache)
+            : base(settingsService, cache, logger)
         {
             EnsureAccountsFile();
         }
@@ -27,16 +28,22 @@ namespace Schaad.Accounting.Repositories
         /// </summary>
         public void SaveAccount(Account account)
         {
-            var accounts = GetAccountList();
+            if (string.IsNullOrEmpty(account.Currency))
-            var existingAccount = accounts.FirstOrDefault(a => a.Id == account.Id);
-
-            if (existingAccount == null)
             {
-                existingAccount = new Account();
+                account.Currency = "CHF";
-                accounts.Add(existingAccount);
+            }
-                account.Id = Guid.NewGuid().ToString();
+
+            var accounts = GetAccountList();
+            var idx = accounts.FindIndex(a => a.Id == account.Id);
+            if (idx >= 0)
+            {
+                accounts[idx] = account;
+            }
+            else
+            {
+                account.Id = Guid.NewGuid().ToString();
+                accounts.Add(account);
             }
-            account.Copy(existingAccount);
             Save(accounts, ACCOUNTS);
         }
 

Schaad.Accounting.Db/Repositories/BankTransactionRepository.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Datasets;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
@@ -10,8 +11,8 @@ namespace Schaad.Accounting.Repositories
     {
         private readonly string BANK_TRANSACTIONS = "BankTransactions.xml";
 
-        public BankTransactionRepository(ISettingsService settingsService, RepositoryCache cache)
+        public BankTransactionRepository(ISettingsService settingsService, RepositoryCache cache, ILogger<BankTransactionRepository> logger)
-            : base(settingsService, cache)
+            : base(settingsService, cache, logger)
         {
         }
 

Schaad.Accounting.Db/Repositories/BaseRepository.cs

@@ -5,6 +5,7 @@ using System.IO;
 using System.Text;
 using System.Xml;
 using System.Xml.Serialization;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Interfaces;
 
 namespace Schaad.Accounting.Repositories
@@ -18,11 +19,13 @@ namespace Schaad.Accounting.Repositories
 
         protected readonly ISettingsService settingsService;
         protected readonly RepositoryCache cache;
+        protected readonly ILogger logger;
 
-        protected BaseRepository(ISettingsService settingsService, RepositoryCache cache)
+        protected BaseRepository(ISettingsService settingsService, RepositoryCache cache, ILogger logger)
         {
             this.settingsService = settingsService;
             this.cache = cache;
+            this.logger = logger;
         }
 
         protected void EnsureFileExists(string fileName)
@@ -79,8 +82,9 @@ namespace Schaad.Accounting.Repositories
 
                     File.Move(tmpPath, filePath, overwrite: true);
                 }
-                catch
+                catch (Exception ex)
                 {
+                    logger.LogError(ex, "Failed to save {FilePath}", filePath);
                     if (File.Exists(tmpPath))
                     {
                         try { File.Delete(tmpPath); } catch { /* best effort */ }

Schaad.Accounting.Db/Repositories/BookingRuleRepository.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
 
@@ -10,8 +11,8 @@ namespace Schaad.Accounting.Repositories
     {
         private readonly string BOOKING_RULES = "BookingRules.xml";
 
-        public BookingRuleRepository(ISettingsService settingsService, RepositoryCache cache)
+        public BookingRuleRepository(ISettingsService settingsService, RepositoryCache cache, ILogger<BookingRuleRepository> logger)
-            : base(settingsService, cache)
+            : base(settingsService, cache, logger)
         {
             EnsureFileExists(BOOKING_RULES);
         }
@@ -27,15 +28,16 @@ namespace Schaad.Accounting.Repositories
         public void SaveBookingRule(BookingRule bookingRule)
         {
             var bookingRules = GetBookingRuleList();
-            var existingRule = bookingRules.FirstOrDefault(a => a.Id == bookingRule.Id);
+            var idx = bookingRules.FindIndex(r => r.Id == bookingRule.Id);
-
+            if (idx >= 0)
-            if (existingRule == null)
             {
-                existingRule = new BookingRule();
+                bookingRules[idx] = bookingRule;
-                bookingRules.Add(existingRule);
+            }
-                bookingRule.Id = Guid.NewGuid().ToString();
+            else
+            {
+                bookingRule.Id = Guid.NewGuid().ToString();
+                bookingRules.Add(bookingRule);
             }
-            bookingRule.Copy(existingRule);
             Save(bookingRules, BOOKING_RULES);
         }
 

Schaad.Accounting.Db/Repositories/BookingTextRepository.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
 
@@ -10,8 +11,8 @@ namespace Schaad.Accounting.Repositories
     {
         private readonly string BOOKING_TEXTS = "BookingTexts.xml";
 
-        public BookingTextRepository(ISettingsService settingsService, RepositoryCache cache)
+        public BookingTextRepository(ISettingsService settingsService, RepositoryCache cache, ILogger<BookingTextRepository> logger)
-            : base(settingsService, cache)
+            : base(settingsService, cache, logger)
         {
             EnsureFileExists(BOOKING_TEXTS);
         }
@@ -27,15 +28,16 @@ namespace Schaad.Accounting.Repositories
         public void SaveBookingText(BookingText bookingText)
         {
             var bookingTexts = GetBookingTextList();
-            var existingText = bookingTexts.FirstOrDefault(a => a.Id == bookingText.Id);
+            var idx = bookingTexts.FindIndex(t => t.Id == bookingText.Id);
-
+            if (idx >= 0)
-            if (existingText == null)
             {
-                existingText = new BookingText();
+                bookingTexts[idx] = bookingText;
-                bookingTexts.Add(existingText);
+            }
-                bookingText.Id = Guid.NewGuid().ToString();
+            else
+            {
+                bookingText.Id = Guid.NewGuid().ToString();
+                bookingTexts.Add(bookingText);
             }
-            bookingText.Copy(existingText);
             Save(bookingTexts, BOOKING_TEXTS);
         }
 

Schaad.Accounting.Db/Repositories/SplitPredefinitionRepository.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
 
@@ -10,8 +11,8 @@ namespace Schaad.Accounting.Repositories
     {
         private readonly string SPLIT_PREDEFINITION = "SplitPredefinitions.xml";
 
-        public SplitPredefinitionRepository(ISettingsService settingsService, RepositoryCache cache)
+        public SplitPredefinitionRepository(ISettingsService settingsService, RepositoryCache cache, ILogger<SplitPredefinitionRepository> logger)
-            : base(settingsService, cache)
+            : base(settingsService, cache, logger)
         {
             EnsureFileExists(SPLIT_PREDEFINITION);
         }
@@ -27,15 +28,16 @@ namespace Schaad.Accounting.Repositories
         public void SaveSplitPredefinition(SplitPredefinition splitPredefinition)
         {
             var definitions = GetSplitPredefinitionList();
-            var existingDefinition = definitions.FirstOrDefault(a => a.Id == splitPredefinition.Id);
+            var idx = definitions.FindIndex(d => d.Id == splitPredefinition.Id);
-
+            if (idx >= 0)
-            if (existingDefinition == null)
             {
-                existingDefinition = new SplitPredefinition();
+                definitions[idx] = splitPredefinition;
-                definitions.Add(existingDefinition);
+            }
-                splitPredefinition.Id = Guid.NewGuid().ToString();
+            else
+            {
+                splitPredefinition.Id = Guid.NewGuid().ToString();
+                definitions.Add(splitPredefinition);
             }
-            splitPredefinition.Copy(existingDefinition);
             Save(definitions, SPLIT_PREDEFINITION);
         }
     }

Schaad.Accounting.Db/Repositories/SubclassRepository.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
 
@@ -11,8 +12,8 @@ namespace Schaad.Accounting.Repositories
         private readonly Dictionary<int, string> classes = new Dictionary<int, string>();
         private readonly string SUBCLASSES = "SubClasses.xml";
 
-        public SubclassRepository(ISettingsService settingsService, RepositoryCache cache)
+        public SubclassRepository(ISettingsService settingsService, RepositoryCache cache, ILogger<SubclassRepository> logger)
-            : base(settingsService, cache)
+            : base(settingsService, cache, logger)
         {
             EnsureFileExists(SUBCLASSES);
 
@@ -28,20 +29,21 @@ namespace Schaad.Accounting.Repositories
         public List<SubClass> GetSubClassList() => LoadList<SubClass>(SUBCLASSES);
 
         /// <summary>
-        /// Save a booking text (insert/update)
+        /// Save a subclass (insert/update)
         /// </summary>
         public void SaveSubClass(SubClass subClass)
         {
             var subclasses = GetSubClassList();
-            var existingSubClass = subclasses.FirstOrDefault(a => a.Id == subClass.Id);
+            var idx = subclasses.FindIndex(s => s.Id == subClass.Id);
-
+            if (idx >= 0)
-            if (existingSubClass == null)
             {
-                existingSubClass = new SubClass();
+                subclasses[idx] = subClass;
-                subclasses.Add(existingSubClass);
+            }
-                subClass.Id = Guid.NewGuid().ToString();
+            else
+            {
+                subClass.Id = Guid.NewGuid().ToString();
+                subclasses.Add(subClass);
             }
-            subClass.Copy(existingSubClass);
             Save(subclasses, SUBCLASSES);
         }
 

Schaad.Accounting.Db/Repositories/TransactionRepository.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
 
@@ -11,8 +12,8 @@ namespace Schaad.Accounting.Repositories
         private readonly IAccountRepository accountRepository;
         private readonly string TRANSACTIONS = "Transactions.xml";
 
-        public TransactionRepository(ISettingsService settingsService, RepositoryCache cache, IAccountRepository accountRepository)
+        public TransactionRepository(ISettingsService settingsService, RepositoryCache cache, IAccountRepository accountRepository, ILogger<TransactionRepository> logger)
-            : base(settingsService, cache)
+            : base(settingsService, cache, logger)
         {
             this.accountRepository = accountRepository;
         }
@@ -44,17 +45,22 @@ namespace Schaad.Accounting.Repositories
                 transaction.FxRate = null;
             }
 
+            if (transaction.BookingDate <= DateTime.MinValue)
+            {
+                transaction.BookingDate = transaction.ValueDate;
+            }
 
             var transactionList = GetTransactionList();
-            var existingTransaction = transactionList.FirstOrDefault(a => a.Id == transaction.Id);
+            var idx = transactionList.FindIndex(t => t.Id == transaction.Id);
-
+            if (idx >= 0)
-            if (existingTransaction == null)
             {
-                existingTransaction = new Transaction();
+                transactionList[idx] = transaction;
-                transactionList.Add(existingTransaction);
+            }
-                transaction.Id = Guid.NewGuid().ToString();
+            else
+            {
+                transaction.Id = Guid.NewGuid().ToString();
+                transactionList.Add(transaction);
             }
-            transaction.Copy(existingTransaction);
             Save(transactionList, TRANSACTIONS);
         }
 
@@ -70,8 +76,7 @@ namespace Schaad.Accounting.Repositories
                 return null;
             }
 
-            var result = new Transaction();
+            var result = stored.Clone();
-            stored.Copy(result);
 
             // value is stored in CHF -> convert back to foreign currency for display/editing
             var isFxAccount = accountRepository.GetAccount(result.OriginAccountId).IsFxAccount

Schaad.Accounting.Db/Schaad.Accounting.Db.csproj

@@ -7,4 +7,8 @@
   <ItemGroup>
     <ProjectReference Include="..\Schaad.Accounting.Common\Schaad.Accounting.Common.csproj" />
   </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.9" />
+  </ItemGroup>
 </Project>

Schaad.Accounting.Services/FileService.cs

@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using System.IO.Compression;
 using System.Linq;
 using System.Text;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Datasets;
 using Schaad.Accounting.Interfaces;
 using Schaad.Finance.Api;
@@ -17,6 +18,7 @@ namespace Schaad.Accounting.Services
         private readonly ISettingsService settingsService;
         private readonly IAccountStatementService accountStatementService;
         private readonly ICreditCardStatementService creditCardStatementService;
+        private readonly ILogger<FileService> logger;
 
         public FileService(
             ISettingsService settingsService,
@@ -24,7 +26,8 @@ namespace Schaad.Accounting.Services
             ITransactionRepository transactionsRepository,
             IBankTransactionRepository bankTransactionRepository,
             IAccountStatementService accountStatementService,
-            ICreditCardStatementService creditCardStatementService)
+            ICreditCardStatementService creditCardStatementService,
+            ILogger<FileService> logger)
         {
             this.settingsService = settingsService;
             this.accountRepository = accountRepository;
@@ -32,6 +35,7 @@ namespace Schaad.Accounting.Services
             this.bankTransactionRepository = bankTransactionRepository;
             this.accountStatementService = accountStatementService;
             this.creditCardStatementService = creditCardStatementService;
+            this.logger = logger;
         }
 
         public string Backup()
@@ -46,6 +50,8 @@ namespace Schaad.Accounting.Services
         // http://www.mikesdotnetting.com/article/288/asp-net-5-uploading-files-with-asp-net-mvc-6
         public IReadOnlyList<MessageDataset> ImportAccountStatementFile(string filePath)
         {
+            logger.LogInformation("Importing account statement file {FilePath}", filePath);
+
             var messages = new List<MessageDataset>();
             var accountStatementResults = accountStatementService.ReadFile(filePath, Encoding.UTF8);
 
@@ -56,6 +62,7 @@ namespace Schaad.Accounting.Services
 
                 if (accountStatementResult.IsSuccess == false)
                 {
+                    logger.LogError("Statement parse failed for account {AccountNumber}: {Error}", account.AccountNumber, accountStatementResult.Error);
                     messages.Add(new MessageDataset($"Account {account.AccountNumber} NICHT importiert: {accountStatementResult.Error}", MessageStatus.Error));
                 }
 
@@ -87,6 +94,9 @@ namespace Schaad.Accounting.Services
                     var count = bankTransactionRepository.SaveBankTransactionList(account.AccountNumber, transactionsThisYear);
                     accountRepository.SaveBankAccountBalance(account.AccountNumber, (decimal)account.EndBalance.Value);
 
+                    logger.LogInformation("Imported {Imported} of {Total} transactions for account {AccountNumber}",
+                        count, account.Transactions.Count, account.AccountNumber);
+
                     var status = count == account.Transactions.Count ? MessageStatus.Success : MessageStatus.Info;
                     message.Add($"{count} von {account.Transactions.Count} Transaktion(en) importiert.", status);
 
@@ -99,6 +109,8 @@ namespace Schaad.Accounting.Services
                 }
                 else
                 {
+                    logger.LogWarning("Skipping account {AccountNumber}: not part of the currently selected mandator ({Skipped} transactions ignored)",
+                        account.AccountNumber, account.Transactions.Count);
                     message.Add($"Falscher Mandant: {account.Transactions.Count} Transaktion(en) nicht importiert.", MessageStatus.Warning);
                 }
             }

Schaad.Accounting.Services/FxConverter.cs

@@ -0,0 +1,21 @@
+using Schaad.Accounting.Datasets;
+using Schaad.Accounting.Interfaces;
+using Schaad.Finance.Api;
+
+namespace Schaad.Accounting.Services
+{
+    public class FxConverter : IFxConverter
+    {
+        private readonly IFxService fxService;
+        private readonly SettingsDataset settings;
+
+        public FxConverter(IFxService fxService, SettingsDataset settings)
+        {
+            this.fxService = fxService;
+            this.settings = settings;
+        }
+
+        public decimal ConvertToChf(decimal amount, string fromCurrency)
+            => fxService.ConvertCurrency(amount, fromCurrency, "CHF", settings.FixerIoApiKey);
+    }
+}

Schaad.Accounting.Services/Interfaces/IFxConverter.cs

@@ -0,0 +1,11 @@
+namespace Schaad.Accounting.Interfaces
+{
+    /// <summary>
+    /// Thin wrapper over the vendor <c>IFxService</c> that hides the FixerIo API key
+    /// and the base currency, so callers just ask "convert this amount to CHF".
+    /// </summary>
+    public interface IFxConverter
+    {
+        decimal ConvertToChf(decimal amount, string fromCurrency);
+    }
+}

Schaad.Accounting.Services/Schaad.Accounting.Services.csproj

@@ -6,6 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="FreeSpire.PDF" Version="10.2.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.9" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Schaad.Accounting.Common\Schaad.Accounting.Common.csproj" />

Schaad.Accounting.Services/SettingsService.cs

@@ -10,12 +10,13 @@ namespace Schaad.Accounting.Services
     public class SettingsService : ISettingsService
     {
         private readonly SettingsDataset settingsDataset;
-        private string mandator = "Claudio Schaad";
+        private string mandator;
         private int year = DateTime.Now.Year;
 
         public SettingsService(SettingsDataset settingsDataset)
         {
             this.settingsDataset = settingsDataset;
+            this.mandator = settingsDataset.DefaultMandator;
         }
 
         public int GetYear()

Schaad.Accounting.Services/ViewService.cs

@@ -1,11 +1,11 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.Extensions.Logging;
 using Schaad.Accounting.Datasets;
 using Schaad.Accounting.Datasets.Reports;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
-using Schaad.Finance.Api;
 using Schaad.Finance.Api.Datasets;
 
 namespace Schaad.Accounting.Services
@@ -17,8 +17,8 @@ namespace Schaad.Accounting.Services
         private readonly IBookingRuleRepository bookingRuleRepository;
         private readonly ISubclassRepository subclassRepository;
         private readonly ITransactionRepository transactionRepository;
-        private readonly IFxService fxService;
+        private readonly IFxConverter fxConverter;
-        private readonly ISettingsService settingsService;
+        private readonly ILogger<ViewService> logger;
 
         public ViewService(
             IAccountRepository accountRepository,
@@ -26,16 +26,16 @@ namespace Schaad.Accounting.Services
             ITransactionRepository transactionRepository,
             ISubclassRepository subclassRepository,
             IBookingRuleRepository bookingRuleRepository,
-            IFxService fxService,
+            IFxConverter fxConverter,
-            ISettingsService settingsService)
+            ILogger<ViewService> logger)
         {
             this.accountRepository = accountRepository;
             this.bankTransactionRepository = bankTransactionRepository;
             this.transactionRepository = transactionRepository;
             this.subclassRepository = subclassRepository;
             this.bookingRuleRepository = bookingRuleRepository;
-            this.fxService = fxService;
+            this.fxConverter = fxConverter;
-            this.settingsService = settingsService;
+            this.logger = logger;
         }
 
         /// <summary>
@@ -55,7 +55,6 @@ namespace Schaad.Accounting.Services
             var accounts = accountRepository.GetAccountList();
             var transactionList = GetTransactionViewList();
             var subClassNameByNumber = subclassRepository.GetSubClassList().ToDictionary(s => s.Number, s => s.Name);
-            var settings = settingsService.GetSettings();
 
             // Group transactions by account so per-account balance is O(k) instead of O(M).
             var creditsByAccount = transactionList.GroupBy(t => t.TargetAccountId).ToDictionary(g => g.Key, g => g.ToList());
@@ -67,8 +66,8 @@ namespace Schaad.Accounting.Services
                     return new AccountDataset(
                         account: a,
                         balance: balance,
-                        balanceCHF: fxService.ConvertCurrency(balance, a.Currency, "CHF", settings.FixerIoApiKey),
+                        balanceCHF: fxConverter.ConvertToChf(balance, a.Currency),
-                        startBalanceCHF: fxService.ConvertCurrency(a.StartBalance, a.Currency, "CHF", settings.FixerIoApiKey),
+                        startBalanceCHF: fxConverter.ConvertToChf(a.StartBalance, a.Currency),
                         className: subclassRepository.GetClass(a.Class),
                         subClassName: subClassNameByNumber[a.SubClass]);
                 })
@@ -111,9 +110,8 @@ namespace Schaad.Accounting.Services
         {
             var accountList = GetAccountViewList();
 
-            var settings = settingsService.GetSettings();
+            var profit = Math.Abs(accountList.Where(m => m.Class == ClassIds.Income).Sum(m => m.BalanceCHF));
-            var profit = Math.Abs(accountList.Where(m => m.Class == ClassIds.Income).Sum(m =>m.BalanceCHF));
+            profit += Math.Abs(accountList.Where(m => m.Class == ClassIds.Activa).Sum(m => fxConverter.ConvertToChf(m.StartBalance, m.Currency)));
-            profit += Math.Abs(accountList.Where(m => m.Class == ClassIds.Activa).Sum(m => fxService.ConvertCurrency(m.StartBalance, m.Currency, "CHF", settings.FixerIoApiKey)));
             var loss = Math.Abs(accountList.Where(m => m.Class == ClassIds.Expenses).Sum(m => m.BalanceCHF));
 
             var balanceView = new BalanceSheetDataset(
@@ -165,8 +163,7 @@ namespace Schaad.Accounting.Services
                 var originAccount = accountsById[t.OriginAccountId];
                 if (originAccount.Class == ClassIds.Activa && accountId == t.OriginAccountId)
                 {
-                    var copy = new Transaction();
+                    var copy = t.Clone();
-                    t.Copy(copy);
                     copy.Value *= -1;
                     return copy;
                 }
@@ -211,7 +208,7 @@ namespace Schaad.Accounting.Services
             var transactions = transactionRepository.GetTransactionList();
             var accounts = accountRepository.GetAccountList();
             var bookingRules = bookingRuleRepository.GetBookingRuleList();
-            var bankTransactions = GetOpenBankTransactionList().OrderBy(t => t.ValueDate);
+            var bankTransactions = GetOpenBankTransactionList().OrderBy(t => t.ValueDate).ToList();
             foreach (var bankTransaction in bankTransactions)
             {
                 var trx = new Transaction(bankTransaction, accounts);
@@ -220,6 +217,9 @@ namespace Schaad.Accounting.Services
                 MatchBankTransactionBySameValueLastMonth(bankTransaction, trx, transactions);
                 newTransactionList.Add(trx);
             }
+
+            var matched = newTransactionList.Count(t => string.IsNullOrEmpty(t.Text) == false);
+            logger.LogInformation("Matched {Matched} of {Total} open bank transactions", matched, bankTransactions.Count);
             return newTransactionList;
         }
 

Schaad.Accounting.Tests/AccountRepositoryTestShould.cs

@@ -1,3 +1,4 @@
+using Microsoft.Extensions.Logging.Abstractions;
 using NSubstitute;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
@@ -21,7 +22,7 @@ public class AccountRepositoryTestShould : IDisposable
         settingsService.GetDbPath().Returns(dbDir);
         settingsService.GetLastYearDbPath().Returns(Path.Combine(dbDir, "no-such-dir"));
 
-        sut = new AccountRepository(settingsService, new RepositoryCache());
+        sut = new AccountRepository(settingsService, new RepositoryCache(), NullLogger<AccountRepository>.Instance);
     }
 
     public void Dispose()
@@ -103,7 +104,7 @@ public class AccountRepositoryTestShould : IDisposable
         sut.SaveAccount(new Account { Number = 1000, Name = "Cash", Currency = "CHF" });
 
         // Re-construct with the same directory: existing file, no year rollover, no data loss.
-        var fresh = new AccountRepository(settingsService, new RepositoryCache());
+        var fresh = new AccountRepository(settingsService, new RepositoryCache(), NullLogger<AccountRepository>.Instance);
 
         var accounts = fresh.GetAccountList();
         accounts.Count.ShouldBe(1);

Schaad.Accounting.Tests/FileServiceTestShould.cs

@@ -1,4 +1,5 @@
 using System.Text;
+using Microsoft.Extensions.Logging.Abstractions;
 using NSubstitute;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
@@ -26,7 +27,7 @@ public class FileServiceTestShould
 
     private FileService BuildService() => new(
         settingsService, accountRepo, transactionRepo, bankTransactionRepo,
-        accountStatementService, creditCardStatementService);
+        accountStatementService, creditCardStatementService, NullLogger<FileService>.Instance);
 
     [Fact]
     public void EmitHeaderRowAndRunningBalanceWhenExportingTransactionsCsv()

Schaad.Accounting.Tests/FxConverterTestShould.cs

@@ -0,0 +1,34 @@
+using NSubstitute;
+using Schaad.Accounting.Datasets;
+using Schaad.Accounting.Services;
+using Schaad.Finance.Api;
+using Shouldly;
+
+namespace Schaad.Accounting.Tests;
+
+public class FxConverterTestShould
+{
+    private readonly IFxService fxService = Substitute.For<IFxService>();
+    private readonly SettingsDataset settings = new() { DataPath = "", FixerIoApiKey = "test-key" };
+
+    private FxConverter BuildConverter() => new(fxService, settings);
+
+    [Fact]
+    public void DelegateToFxServiceWithChfAsTargetAndConfiguredApiKeyWhenConverting()
+    {
+        fxService.ConvertCurrency(100m, "USD", "CHF", "test-key").Returns(90m);
+
+        var result = BuildConverter().ConvertToChf(100m, "USD");
+
+        result.ShouldBe(90m);
+        fxService.Received(1).ConvertCurrency(100m, "USD", "CHF", "test-key");
+    }
+
+    [Fact]
+    public void PassNegativeAmountsThroughWhenConverting()
+    {
+        fxService.ConvertCurrency(-50m, "EUR", "CHF", Arg.Any<string>()).Returns(-48m);
+
+        BuildConverter().ConvertToChf(-50m, "EUR").ShouldBe(-48m);
+    }
+}

Schaad.Accounting.Tests/TransactionRepositoryTestShould.cs

@@ -1,3 +1,4 @@
+using Microsoft.Extensions.Logging.Abstractions;
 using NSubstitute;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
@@ -25,7 +26,7 @@ public class TransactionRepositoryTestShould : IDisposable
 
         accountRepo = Substitute.For<IAccountRepository>();
         cache = new RepositoryCache();
-        sut = new TransactionRepository(settingsService, cache, accountRepo);
+        sut = new TransactionRepository(settingsService, cache, accountRepo, NullLogger<TransactionRepository>.Instance);
     }
 
     public void Dispose()
@@ -135,4 +136,43 @@ public class TransactionRepositoryTestShould : IDisposable
 
         sut.GetTransactionList().ShouldBeEmpty();
     }
+
+    [Fact]
+    public void PreserveRelatedPartyWhenRoundTrippingTransaction()
+    {
+        accountRepo.GetAccount(Arg.Any<string>()).Returns(new Account { Currency = "CHF" });
+
+        sut.SaveTransaction(new Transaction
+        {
+            OriginAccountId = "a",
+            TargetAccountId = "b",
+            Value = 10m,
+            Text = "Rent",
+            RelatedParty = "ACME Property AG",
+            ValueDate = new DateTime(2026, 4, 1),
+            BookingDate = new DateTime(2026, 4, 1)
+        });
+
+        // Regression: earlier Transaction.Copy dropped RelatedParty on every save,
+        // so the round-trip lost it.
+        sut.GetTransactionList().Single().RelatedParty.ShouldBe("ACME Property AG");
+    }
+
+    [Fact]
+    public void DefaultBookingDateToValueDateWhenBookingDateIsUnset()
+    {
+        accountRepo.GetAccount(Arg.Any<string>()).Returns(new Account { Currency = "CHF" });
+
+        sut.SaveTransaction(new Transaction
+        {
+            OriginAccountId = "a",
+            TargetAccountId = "b",
+            Value = 10m,
+            Text = "x",
+            ValueDate = new DateTime(2026, 4, 15)
+            // BookingDate left at default (DateTime.MinValue)
+        });
+
+        sut.GetTransactionList().Single().BookingDate.ShouldBe(new DateTime(2026, 4, 15));
+    }
 }

Schaad.Accounting.Tests/ViewServiceTestShould.cs

@@ -1,9 +1,8 @@
+using Microsoft.Extensions.Logging.Abstractions;
 using NSubstitute;
-using Schaad.Accounting.Datasets;
 using Schaad.Accounting.Interfaces;
 using Schaad.Accounting.Models;
 using Schaad.Accounting.Services;
-using Schaad.Finance.Api;
 using Shouldly;
 
 namespace Schaad.Accounting.Tests;
@@ -15,8 +14,7 @@ public class ViewServiceTestShould
     private readonly IBankTransactionRepository bankTransactionRepo = Substitute.For<IBankTransactionRepository>();
     private readonly IBookingRuleRepository bookingRuleRepo = Substitute.For<IBookingRuleRepository>();
     private readonly ISubclassRepository subclassRepo = Substitute.For<ISubclassRepository>();
-    private readonly IFxService fxService = Substitute.For<IFxService>();
+    private readonly IFxConverter fxConverter = Substitute.For<IFxConverter>();
-    private readonly ISettingsService settingsService = Substitute.For<ISettingsService>();
 
     public ViewServiceTestShould()
     {
@@ -24,15 +22,14 @@ public class ViewServiceTestShould
         subclassRepo.GetSubClassList().Returns(
             Enumerable.Range(10, 50).Select(n => new SubClass { Number = n, Name = "sub-" + n }).ToList());
         subclassRepo.GetClass(Arg.Any<int>()).Returns("");
-        settingsService.GetSettings().Returns(new SettingsDataset { DataPath = "", FixerIoApiKey = "" });
 
         // Passthrough FX by default (CHF-only). Individual tests can override.
-        fxService.ConvertCurrency(Arg.Any<decimal>(), Arg.Any<string>(), Arg.Any<string>(), Arg.Any<string>())
+        fxConverter.ConvertToChf(Arg.Any<decimal>(), Arg.Any<string>())
             .Returns(ci => ci.ArgAt<decimal>(0));
     }
 
     private ViewService BuildService() =>
-        new(accountRepo, bankTransactionRepo, transactionRepo, subclassRepo, bookingRuleRepo, fxService, settingsService);
+        new(accountRepo, bankTransactionRepo, transactionRepo, subclassRepo, bookingRuleRepo, fxConverter, NullLogger<ViewService>.Instance);
 
     // --- Balance math ---------------------------------------------------------
 
@@ -82,7 +79,7 @@ public class ViewServiceTestShould
         transactionRepo.GetTransactionList().Returns(new List<Transaction>());
 
         // 1 USD = 0.90 CHF
-        fxService.ConvertCurrency(Arg.Any<decimal>(), "USD", "CHF", Arg.Any<string>())
+        fxConverter.ConvertToChf(Arg.Any<decimal>(), "USD")
             .Returns(ci => ci.ArgAt<decimal>(0) * 0.9m);
 
         var account = BuildService().GetAccountViewList().Single();

Schaad.Accounting.UI/Components/Pages/Home.razor.cs

@@ -22,9 +22,6 @@ public partial class Home : ComponentBase
     [Inject]
     private IDialogService dialogService { get; set; } = null!;
 
-    [Inject]
-    private ISettingsService settingsService { get; set; } = null!;
-    
     [Inject]
     private IFileService fileService { get; set; } = null!;
     
@@ -47,17 +44,11 @@ public partial class Home : ComponentBase
     bool IsCanceled;
     Dictionary<int, string> Files = new();
 
-    private bool loaded;
-
     protected override Task OnInitializedAsync()
     {
-        if (loaded == false) {
+        matchingBankTransactions = viewService.MatchOpenBankTransactions();
-            matchingBankTransactions = viewService.MatchOpenBankTransactions();
+        accounts = viewService.GetAccountViewList();
-            accounts = viewService.GetAccountViewList();
+        bookingTexts = bookingTextRepository.GetBookingTextList().Select(b => b.Text).ToArray();
-            bookingTexts = bookingTextRepository.GetBookingTextList().Select(b => b.Text).ToArray();
-            loaded = true;
-        }
-
         return base.OnInitializedAsync();
     }
     

Schaad.Accounting.UI/Extensions.cs

@@ -31,6 +31,7 @@ namespace Schaad.Accounting.UI
             services.AddScoped<IAccountStatementService, AccountStatementService>();
             services.AddScoped<ICreditCardStatementService, CreditCardStatementService>();
             services.AddSingleton<IFxService, DummyFxService>();
+            services.AddScoped<IFxConverter, FxConverter>();
             services.AddSingleton<IPdfParsingService, PdfParsingService>();
 
             return services;

Schaad.Accounting.UI/appsettings.Development.json

@@ -7,6 +7,7 @@
   },
   "Settings": {
     "DataPath": "D:\\Developer\\AccountingData\\",
-    "FixerIoApiKey": "ee23142f1120bb1223b0e76f98abfa97"
+    "FixerIoApiKey": "ee23142f1120bb1223b0e76f98abfa97",
+    "DefaultMandator": "Claudio Schaad"
   }
 }