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lib/shared/services/premium_manager.dart

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+import 'package:shared_preferences/shared_preferences.dart';
+import '../models/user_model.dart';
+import 'billing_service.dart';
+
+class PremiumManager {
+  static const _keyIsPremium = 'is_premium';
+  static const _keyPurchaseToken = 'purchase_token';
+
+  final SharedPreferences _prefs;
+  final BillingService _billing;
+
+  PremiumManager(this._prefs, this._billing);
+
+  bool get isPremium => _prefs.getBool(_keyIsPremium) ?? false;
+  String? get purchaseToken => _prefs.getString(_keyPurchaseToken);
+
+  Future<void> _setPremium(bool value, String? token) async {
+    await _prefs.setBool(_keyIsPremium, value);
+    if (token != null) {
+      await _prefs.setString(_keyPurchaseToken, token);
+    } else if (!value) {
+      await _prefs.remove(_keyPurchaseToken);
+    }
+  }
+
+  Future<PurchaseResult> purchase() async {
+    final result = await _billing.purchasePro();
+    if (result.success && result.purchaseToken != null) {
+      await _setPremium(true, result.purchaseToken);
+      await _billing.completePurchase(result.purchaseToken!);
+    }
+    return result;
+  }
+
+  Future<PurchaseResult> restore() async {
+    final result = await _billing.restorePurchases();
+    if (result.success && result.purchaseToken != null) {
+      await _setPremium(true, result.purchaseToken);
+      await _billing.completePurchase(result.purchaseToken!);
+    }
+    return result;
+  }
+
+  Future<void> autoRestore() async {
+    if (isPremium) return;
+    final result = await _billing.queryPastPurchase();
+    if (result.success && result.purchaseToken != null) {
+      await _setPremium(true, result.purchaseToken);
+      await _billing.completePurchase(result.purchaseToken!);
+    }
+  }
+
+  UserPlan get currentPlan => isPremium ? UserPlan.vip : UserPlan.free;
+
+  Future<void> clear() async {
+    await _setPremium(false, null);
+  }
+}