import 'dart:async';
import 'package:crypto/crypto.dart';
import 'billing_models.dart';
import 'billing_service.dart';
import 'product_catalog.dart';

/// Test/Mock implementation of [BillingService] for automated test suites.
/// Never selected in release execution paths.
class FakeBillingService implements BillingService {
  final StreamController<List<StorePurchase>> _purchaseStreamController =
      StreamController<List<StorePurchase>>.broadcast();

  final Set<String> _completedPurchaseTokens = <String>{};
  bool available = true;
  bool initializeSuccess = true;
  List<StoreProduct> mockProducts = [
    const StoreProduct(
      id: ProductCatalog.proMonthly,
      title: 'MotorSignal Pro Monthly',
      description: 'Monthly unlimited access to all Pro features',
      price: '\$4.99',
      rawPrice: 4.99,
      currencyCode: 'USD',
      currencySymbol: '\$',
      isSubscription: true,
    ),
    const StoreProduct(
      id: ProductCatalog.proLifetime,
      title: 'MotorSignal Pro Lifetime',
      description: 'Permanent unlimited access to all Pro features',
      price: '\$49.99',
      rawPrice: 49.99,
      currencyCode: 'USD',
      currencySymbol: '\$',
      isSubscription: false,
    ),
  ];

  int launchCount = 0;
  int restoreCount = 0;
  String? lastPurchasedProductId;

  @override
  Stream<List<StorePurchase>> get purchaseStream =>
      _purchaseStreamController.stream;

  @override
  Future<bool> initialize() async => initializeSuccess && available;

  @override
  Future<bool> isAvailable() async => available;

  @override
  Future<List<StoreProduct>> queryProducts() async {
    if (!available) return [];
    return mockProducts;
  }

  @override
  Future<bool> launchPurchaseFlow(String productId) async {
    launchCount++;
    lastPurchasedProductId = productId;
    if (!available || !ProductCatalog.isValidProduct(productId)) return false;
    return true;
  }

  @override
  Future<void> restorePurchases() async {
    restoreCount++;
  }

  @override
  Future<void> completePurchase(StorePurchase purchase) async {
    final token = purchase.purchaseToken ?? purchase.purchaseId;
    _completedPurchaseTokens.add(token);
  }

  bool isPurchaseCompleted(String tokenOrId) =>
      _completedPurchaseTokens.contains(tokenOrId);

  /// Helper for tests to simulate incoming purchase events from the store.
  void emitPurchases(List<StorePurchase> purchases) {
    if (!_purchaseStreamController.isClosed) {
      _purchaseStreamController.add(purchases);
    }
  }

  /// Helper to create a fake StorePurchase for tests.
  StorePurchase createFakePurchase({
    required String productId,
    required StorePurchaseStatus status,
    String? purchaseId,
    String? token,
    bool pendingComplete = true,
  }) {
    final pToken =
        token ?? 'fake_token_${DateTime.now().millisecondsSinceEpoch}';
    return StorePurchase(
      purchaseId:
          purchaseId ??
          'fake_purchase_${DateTime.now().millisecondsSinceEpoch}',
      productId: productId,
      status: status,
      transactionDate: DateTime.now().toIso8601String(),
      purchaseToken: pToken,
      purchaseTokenHash: sha256.convert(pToken.codeUnits).toString(),
      pendingCompletePurchase: pendingComplete,
    );
  }

  @override
  void dispose() {
    _purchaseStreamController.close();
  }
}