//using the example code with removing unnecessary code

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:in_app_purchase/in_app_purchase.dart';
import 'package:in_app_purchase_storekit/in_app_purchase_storekit.dart';
import 'package:in_app_purchase_storekit/store_kit_wrappers.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();

  runApp(_MyApp());
}


const String _kUpgradeId =
    'remove_ads'; //TODO: Change this to your product ID
const List<String> _kProductIds = <String>[
  _kUpgradeId,
];

class _MyApp extends StatefulWidget {
  @override
  State<_MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<_MyApp> {
  final InAppPurchase _inAppPurchase = InAppPurchase.instance;
  late StreamSubscription<List<PurchaseDetails>> _subscription;
  List<String> _notFoundIds = <String>[];
  List<ProductDetails> _products = <ProductDetails>[];
  List<PurchaseDetails> _purchases = <PurchaseDetails>[];
  bool _isAvailable = false;
  bool _purchasePending = false;
  bool _loading = true;
  String? _queryProductError;

  @override
  void initState() {
    final Stream<List<PurchaseDetails>> purchaseUpdated =
        _inAppPurchase.purchaseStream;
    _subscription =
        purchaseUpdated.listen((List<PurchaseDetails> purchaseDetailsList) {
      _listenToPurchaseUpdated(purchaseDetailsList);
    }, onDone: () {
      _subscription.cancel();
    }, onError: (Object error) {
      // handle error here.
    });
    initStoreInfo();
    super.initState();
  }

  Future<void> initStoreInfo() async {
    final bool isAvailable = await _inAppPurchase.isAvailable();
    if (!isAvailable) {
      setState(() {
        _isAvailable = isAvailable;
        _products = <ProductDetails>[];
        _purchases = <PurchaseDetails>[];
        _notFoundIds = <String>[];
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    if (Platform.isIOS) {
      final InAppPurchaseStoreKitPlatformAddition iosPlatformAddition =
          _inAppPurchase
              .getPlatformAddition<InAppPurchaseStoreKitPlatformAddition>();
      await iosPlatformAddition.setDelegate(ExamplePaymentQueueDelegate());
    }

    final ProductDetailsResponse productDetailResponse =
        await _inAppPurchase.queryProductDetails(_kProductIds.toSet());
    if (productDetailResponse.error != null) {
      setState(() {
        _queryProductError = productDetailResponse.error!.message;
        _isAvailable = isAvailable;
        _products = productDetailResponse.productDetails;
        _purchases = <PurchaseDetails>[];
        _notFoundIds = productDetailResponse.notFoundIDs;
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    if (productDetailResponse.productDetails.isEmpty) {
      setState(() {
        _queryProductError = null;
        _isAvailable = isAvailable;
        _products = productDetailResponse.productDetails;
        _purchases = <PurchaseDetails>[];
        _notFoundIds = productDetailResponse.notFoundIDs;
        _purchasePending = false;
        _loading = false;
      });
      return;
    }

    setState(() {
      _isAvailable = isAvailable;
      _products = productDetailResponse.productDetails;
      _notFoundIds = productDetailResponse.notFoundIDs;
      _purchasePending = false;
      _loading = false;
    });
  }

  @override
  void dispose() {
    if (Platform.isIOS) {
      final InAppPurchaseStoreKitPlatformAddition iosPlatformAddition =
          _inAppPurchase
              .getPlatformAddition<InAppPurchaseStoreKitPlatformAddition>();
      iosPlatformAddition.setDelegate(null);
    }
    _subscription.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final List<Widget> stack = <Widget>[];
    if (_queryProductError == null) {
      stack.add(
        ListView(
          children: <Widget>[
            _buildConnectionCheckTile(),
            _buildProductList(),
            _buildRestoreButton(),
          ],
        ),
      );
    } else {
      stack.add(Center(
        child: Text(_queryProductError!),
      ));
    }
    if (_purchasePending) {
      stack.add(
        const Stack(
          children: <Widget>[
            Opacity(
              opacity: 0.3,
              child: ModalBarrier(dismissible: false, color: Colors.grey),
            ),
            Center(
              child: CircularProgressIndicator(),
            ),
          ],
        ),
      );
    }

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('IAP Example'),
        ),
        body: Stack(
          children: stack,
        ),
      ),
    );
  }

  Card _buildConnectionCheckTile() {
    if (_loading) {
      return const Card(child: ListTile(title: Text('Trying to connect...')));
    }
    final Widget storeHeader = ListTile(
      leading: Icon(_isAvailable ? Icons.check : Icons.block,
          color: _isAvailable
              ? Colors.green
              : ThemeData.light().colorScheme.error),
      title:
          Text('The store is ${_isAvailable ? 'available' : 'unavailable'}.'),
    );
    final List<Widget> children = <Widget>[storeHeader];

    if (!_isAvailable) {
      children.addAll(<Widget>[
        const Divider(),
        ListTile(
          title: Text('Not connected',
              style: TextStyle(color: ThemeData.light().colorScheme.error)),
          subtitle: const Text(
              'Unable to connect to the payments processor. Has this app been configured correctly? See the example README for instructions.'),
        ),
      ]);
    }
    return Card(child: Column(children: children));
  }

  Card _buildProductList() {
    if (_loading) {
      return const Card(
          child: ListTile(
              leading: CircularProgressIndicator(),
              title: Text('Fetching products...')));
    }
    if (!_isAvailable) {
      return const Card();
    }
    const ListTile productHeader = ListTile(title: Text('Products for Sale'));
    final List<ListTile> productList = <ListTile>[];
    if (_notFoundIds.isNotEmpty) {
      productList.add(ListTile(
          title: Text('[${_notFoundIds.join(", ")}] not found',
              style: TextStyle(color: ThemeData.light().colorScheme.error)),
          subtitle: const Text(
              'This app needs special configuration to run. Please see example/README.md for instructions.')));
    }

    // This loading previous purchases code is just a demo. Please do not use this as it is.
    // In your app you should always verify the purchase data using the `verificationData` inside the [PurchaseDetails] object before trusting it.
    // We recommend that you use your own server to verify the purchase data.
    final Map<String, PurchaseDetails> purchases =
        Map<String, PurchaseDetails>.fromEntries(
            _purchases.map((PurchaseDetails purchase) {
      if (purchase.pendingCompletePurchase) {
        _inAppPurchase.completePurchase(purchase);
      }
      return MapEntry<String, PurchaseDetails>(purchase.productID, purchase);
    }));
    productList.addAll(_products.map(
      (ProductDetails productDetails) {
        final PurchaseDetails? previousPurchase = purchases[productDetails.id];
        return ListTile(
          title: Text(
            productDetails.title,
          ),
          subtitle: Text(
            productDetails.description,
          ),
          trailing: previousPurchase != null && Platform.isIOS
              ? IconButton(
                  onPressed: () => confirmPriceChange(context),
                  icon: const Icon(Icons.upgrade))
              : TextButton(
                  style: TextButton.styleFrom(
                    backgroundColor: Colors.green[800],
                    foregroundColor: Colors.white,
                  ),
                  onPressed: () {
                    late PurchaseParam purchaseParam;

                    purchaseParam = PurchaseParam(
                      productDetails: productDetails,
                    );

                    _inAppPurchase.buyNonConsumable(
                        purchaseParam: purchaseParam);
                  },
                  child: Text(productDetails.price),
                ),
        );
      },
    ));

    return Card(
        child: Column(
            children: <Widget>[productHeader, const Divider()] + productList));
  }

  Widget _buildRestoreButton() {
    if (_loading) {
      return Container();
    }

    return Padding(
      padding: const EdgeInsets.all(4.0),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: <Widget>[
          TextButton(
            style: TextButton.styleFrom(
              backgroundColor: Theme.of(context).primaryColor,
              foregroundColor: Colors.white,
            ),
            onPressed: () => _inAppPurchase.restorePurchases(),
            child: const Text('Restore purchases'),
          ),
        ],
      ),
    );
  }

  void showPendingUI() {
    setState(() {
      _purchasePending = true;
    });
  }

  Future<void> deliverProduct(PurchaseDetails purchaseDetails) async {
    // IMPORTANT!! Always verify purchase details before delivering the product.
    setState(() {
      _purchases.add(purchaseDetails);
      _purchasePending = false;
    });
  }

  void handleError(IAPError error) {
    setState(() {
      _purchasePending = false;
    });
  }

  Future<bool> _verifyPurchase(PurchaseDetails purchaseDetails) {
    // IMPORTANT!! Always verify a purchase before delivering the product.
    // For the purpose of an example, we directly return true.
    return Future<bool>.value(true);
  }

  void _handleInvalidPurchase(PurchaseDetails purchaseDetails) {
    // handle invalid purchase here if  _verifyPurchase` failed.
  }

  Future<void> _listenToPurchaseUpdated(
      List<PurchaseDetails> purchaseDetailsList) async {
    for (final PurchaseDetails purchaseDetails in purchaseDetailsList) {
      if (purchaseDetails.status == PurchaseStatus.pending) {
        showPendingUI();
      } else {
        if (purchaseDetails.status == PurchaseStatus.error) {
          handleError(purchaseDetails.error!);
        } else if (purchaseDetails.status == PurchaseStatus.purchased ||
            purchaseDetails.status == PurchaseStatus.restored) {
            if (purchaseDetails.status == PurchaseStatus.purchased) {
               debugPrint('IT IS PURCHASED');
            } else {
               debugPrint('IT IS RESTORED');
            }
          final bool valid = await _verifyPurchase(purchaseDetails);
          if (valid) {
            unawaited(deliverProduct(purchaseDetails));
          } else {
            _handleInvalidPurchase(purchaseDetails);
            return;
          }
        }
        if (purchaseDetails.pendingCompletePurchase) {
          await _inAppPurchase.completePurchase(purchaseDetails);
        }
      }
    }
  }

  Future<void> confirmPriceChange(BuildContext context) async {
    // Price changes for Android are not handled by the application, but are
    // instead handled by the Play Store. See
    // https://developer.android.com/google/play/billing/price-changes for more
    // information on price changes on Android.
    if (Platform.isIOS) {
      final InAppPurchaseStoreKitPlatformAddition iapStoreKitPlatformAddition =
          _inAppPurchase
              .getPlatformAddition<InAppPurchaseStoreKitPlatformAddition>();
      await iapStoreKitPlatformAddition.showPriceConsentIfNeeded();
    }
  }
}

/// Example implementation of the
/// [`SKPaymentQueueDelegate`](https://developer.apple.com/documentation/storekit/skpaymentqueuedelegate?language=objc).
///
/// The payment queue delegate can be implementated to provide information
/// needed to complete transactions.
class ExamplePaymentQueueDelegate implements SKPaymentQueueDelegateWrapper {
  @override
  bool shouldContinueTransaction(
      SKPaymentTransactionWrapper transaction, SKStorefrontWrapper storefront) {
    return true;
  }

  @override
  bool shouldShowPriceConsent() {
    return false;
  }
}