add alot

lib/services/bar_tab_service.dart

@@ -231,7 +231,6 @@ class DriftBarTabService implements BarTabService {
       final items = await _getItemsForTab(tabId);
 
       if (items.isEmpty) {
-        // Nothing to settle, leave the tab as-is.
         return;
       }
 
@@ -263,9 +262,6 @@ class DriftBarTabService implements BarTabService {
         ..where((item) => item.tabId.equals(tabId));
 
       await deleteQuery.go();
-
-      // Note: tab status/customerName untouched on purpose — the tab
-      // stays open so it keeps showing in the open tabs list.
     });
   }
 

lib/services/pin_lock_service.dart

@@ -4,12 +4,9 @@ import 'dart:math';
 import 'package:crypto/crypto.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 
-/// Stores and verifies a PIN. The raw PIN is never persisted — only a
-/// salted SHA-256 hash of it, kept in secure storage (Keychain on iOS,
-/// EncryptedSharedPreferences/Keystore on Android).
 class PinLockService {
   PinLockService({FlutterSecureStorage? storage})
-      : _storage = storage ?? const FlutterSecureStorage();
+    : _storage = storage ?? const FlutterSecureStorage();
 
   static const _saltKey = 'pin_salt';
   static const _hashKey = 'pin_hash';
@@ -53,4 +50,4 @@ class PinLockService {
     final bytes = utf8.encode('$salt:$pin');
     return sha256.convert(bytes).toString();
   }
-}
+}

lib/services/product_service.dart

@@ -21,6 +21,9 @@ abstract class ProductService {
   Future<void> updateProduct(Product product);
 
   Future<void> deleteProduct(String id);
+
+  Future<void> decreaseStock(String productId, int amount);
+  Future<void> increaseStock(String productId, int amount);
 }
 
 class DriftProductService implements ProductService {
@@ -118,4 +121,39 @@ class DriftProductService implements ProductService {
 
     await query.go();
   }
+
+  @override
+  Future<void> decreaseStock(String productId, int amount) async {
+    final product = await getProductById(productId);
+
+    if (product == null) {
+      throw Exception('Product not found');
+    }
+
+    if (product.stockQuantity < amount) {
+      throw Exception('Not enough stock');
+    }
+
+    await updateProduct(
+      product.copyWith(
+        stockQuantity: product.stockQuantity - amount,
+      ),
+    );
+  }
+
+  @override
+  Future<void> increaseStock(String productId, int amount) async {
+    final product = await getProductById(productId);
+
+    if (product == null) {
+      throw Exception('Product not found');
+    }
+
+    await updateProduct(
+      product.copyWith(
+        stockQuantity: product.stockQuantity + amount,
+      ),
+    );
+  }
+
 }

lib/services/settings_service.dart

@@ -0,0 +1,50 @@
+import 'package:drift/drift.dart';
+
+import '../database/app_database.dart';
+import '../models/settings.dart';
+
+abstract class SettingsService {
+  Future<AppSettings> getSettings();
+
+  Future<void> saveSettings(AppSettings settings);
+}
+
+class DriftSettingsService implements SettingsService {
+  final AppDatabase database;
+  static const _settingsId = 'app_settings';
+
+  DriftSettingsService({required this.database});
+
+  AppSettings _mapRowToSettings(AppSettingsRow row) {
+    return AppSettings(
+      pinRequired: row.pinRequired,
+      themeMode: AppThemeMode.values.firstWhere(
+            (mode) => mode.name == row.themeMode,
+        orElse: () => AppThemeMode.system,
+      ),
+    );
+  }
+
+  @override
+  Future<AppSettings> getSettings() async {
+    final query = database.select(database.appSettingsTable)
+      ..where((s) => s.id.equals(_settingsId));
+
+    final row = await query.getSingleOrNull();
+
+    if (row == null) return AppSettings.defaults;
+
+    return _mapRowToSettings(row);
+  }
+
+  @override
+  Future<void> saveSettings(AppSettings settings) async {
+    await database.into(database.appSettingsTable).insertOnConflictUpdate(
+      AppSettingsTableCompanion.insert(
+        id: _settingsId,
+        pinRequired: Value(settings.pinRequired),
+        themeMode: Value(settings.themeMode.name),
+      ),
+    );
+  }
+}