import 'dart:async'; import 'dart:collection'; import 'dart:convert'; import 'package:bitcoin_base/bitcoin_base.dart'; import 'package:cake_wallet/core/create_trade_result.dart'; import 'package:cw_core/crypto_currency.dart'; import 'package:cw_core/sync_status.dart'; import 'package:cw_core/transaction_priority.dart'; import 'package:cw_core/wallet_type.dart'; import 'package:hive/hive.dart'; import 'package:http/http.dart' as http; import 'package:intl/intl.dart'; import 'package:mobx/mobx.dart'; import 'package:shared_preferences/shared_preferences.dart'; import 'package:cake_wallet/.secrets.g.dart' as secrets; import 'package:cake_wallet/bitcoin/bitcoin.dart'; import 'package:cake_wallet/bitcoin_cash/bitcoin_cash.dart'; import 'package:cake_wallet/core/wallet_change_listener_view_model.dart'; import 'package:cake_wallet/entities/exchange_api_mode.dart'; import 'package:cake_wallet/entities/preferences_key.dart'; import 'package:cake_wallet/entities/wallet_contact.dart'; import 'package:cake_wallet/ethereum/ethereum.dart'; import 'package:cake_wallet/exchange/exchange_provider_description.dart'; import 'package:cake_wallet/exchange/exchange_template.dart'; import 'package:cake_wallet/exchange/exchange_trade_state.dart'; import 'package:cake_wallet/exchange/limits.dart'; import 'package:cake_wallet/exchange/limits_state.dart'; import 'package:cake_wallet/exchange/provider/changenow_exchange_provider.dart'; import 'package:cake_wallet/exchange/provider/exchange_provider.dart'; import 'package:cake_wallet/exchange/provider/exolix_exchange_provider.dart'; import 'package:cake_wallet/exchange/provider/quantex_exchange_provider.dart'; import 'package:cake_wallet/exchange/provider/sideshift_exchange_provider.dart'; import 'package:cake_wallet/exchange/provider/simpleswap_exchange_provider.dart'; import 'package:cake_wallet/exchange/provider/thorchain_exchange.provider.dart'; import 'package:cake_wallet/exchange/provider/trocador_exchange_provider.dart'; import 'package:cake_wallet/exchange/trade.dart'; import 'package:cake_wallet/exchange/trade_request.dart'; import 'package:cake_wallet/generated/i18n.dart'; import 'package:cake_wallet/monero/monero.dart'; import 'package:cake_wallet/polygon/polygon.dart'; import 'package:cake_wallet/store/app_store.dart'; import 'package:cake_wallet/store/dashboard/trades_store.dart'; import 'package:cake_wallet/store/settings_store.dart'; import 'package:cake_wallet/store/templates/exchange_template_store.dart'; import 'package:cake_wallet/utils/feature_flag.dart'; import 'package:cake_wallet/view_model/contact_list/contact_list_view_model.dart'; part 'exchange_view_model.g.dart'; class ExchangeViewModel = ExchangeViewModelBase with _$ExchangeViewModel; abstract class ExchangeViewModelBase extends WalletChangeListenerViewModel with Store { @override void onWalletChange(wallet) { receiveCurrency = wallet.currency; depositCurrency = wallet.currency; } ExchangeViewModelBase( AppStore appStore, this.trades, this._exchangeTemplateStore, this.tradesStore, this._settingsStore, this.sharedPreferences, this.contactListViewModel, ) : _cryptoNumberFormat = NumberFormat(), isSendAllEnabled = false, isFixedRateMode = false, isReceiveAmountEntered = false, depositAmount = '', receiveAmount = '', receiveAddress = '', depositAddress = '', isDepositAddressEnabled = false, isReceiveAmountEditable = false, _useTorOnly = false, receiveCurrencies = [], depositCurrencies = [], limits = Limits(min: 0, max: 0), tradeState = ExchangeTradeStateInitial(), limitsState = LimitsInitialState(), receiveCurrency = appStore.wallet!.currency, depositCurrency = appStore.wallet!.currency, providerList = [], selectedProviders = ObservableList(), super(appStore: appStore) { _useTorOnly = _settingsStore.exchangeStatus == ExchangeApiMode.torOnly; _setProviders(); const excludeDepositCurrencies = [CryptoCurrency.btt]; const excludeReceiveCurrencies = [ CryptoCurrency.xlm, CryptoCurrency.xrp, CryptoCurrency.bnb, CryptoCurrency.btt ]; _initialPairBasedOnWallet(); final Map exchangeProvidersSelection = json.decode(sharedPreferences.getString(PreferencesKey.exchangeProvidersSelection) ?? "{}") as Map; /// if the provider is not in the user settings (user's first time or newly added provider) /// then use its default value decided by us selectedProviders = ObservableList.of(providerList .where((element) => exchangeProvidersSelection[element.title] == null ? element.isEnabled : (exchangeProvidersSelection[element.title] as bool)) .toList()); _setAvailableProviders(); _calculateBestRate(); bestRateSync = Timer.periodic(Duration(seconds: 10), (timer) => _calculateBestRate()); isDepositAddressEnabled = !(depositCurrency == wallet.currency); depositAmount = ''; receiveAmount = ''; receiveAddress = ''; depositAddress = depositCurrency == wallet.currency ? wallet.walletAddresses.address : ''; provider = providersForCurrentPair().first; final initialProvider = provider; provider!.checkIsAvailable().then((bool isAvailable) { if (!isAvailable && provider == initialProvider) { provider = providerList.firstWhere((provider) => provider is ChangeNowExchangeProvider, orElse: () => providerList.last); _onPairChange(); } }); receiveCurrencies = CryptoCurrency.all .where((cryptoCurrency) => !excludeReceiveCurrencies.contains(cryptoCurrency)) .toList(); depositCurrencies = CryptoCurrency.all .where((cryptoCurrency) => !excludeDepositCurrencies.contains(cryptoCurrency)) .toList(); _defineIsReceiveAmountEditable(); loadLimits(); reaction((_) => isFixedRateMode, (Object _) { loadLimits(); _bestRate = 0; _calculateBestRate(); }); } bool _useTorOnly; final Box trades; final ExchangeTemplateStore _exchangeTemplateStore; final TradesStore tradesStore; final SharedPreferences sharedPreferences; List get _allProviders => [ ChangeNowExchangeProvider(settingsStore: _settingsStore), SideShiftExchangeProvider(), SimpleSwapExchangeProvider(), ThorChainExchangeProvider(tradesStore: trades), if (FeatureFlag.isExolixEnabled) ExolixExchangeProvider(), QuantexExchangeProvider(), TrocadorExchangeProvider( useTorOnly: _useTorOnly, providerStates: _settingsStore.trocadorProviderStates), ]; @observable ExchangeProvider? provider; /// Maps in dart are not sorted by default /// SplayTreeMap is a map sorted by keys /// will use it to sort available providers /// based on the rate they yield for the current trade /// /// /// initialize with descending comparator /// since we want largest rate first final SplayTreeMap _sortedAvailableProviders = SplayTreeMap((double a, double b) => b.compareTo(a)); final List _tradeAvailableProviders = []; @observable ObservableList selectedProviders; @observable List providerList; @observable CryptoCurrency depositCurrency; @observable CryptoCurrency receiveCurrency; @observable LimitsState limitsState; @observable ExchangeTradeState tradeState; @observable String depositAmount; @observable String receiveAmount; @observable String depositAddress; @observable String receiveAddress; @observable bool isDepositAddressEnabled; @observable bool isReceiveAmountEntered; @observable bool isReceiveAmountEditable; @observable bool isFixedRateMode; @observable bool isSendAllEnabled; @observable Limits limits; @computed SyncStatus get status => wallet.syncStatus; @computed ObservableList get templates => _exchangeTemplateStore.templates; @computed List get walletContactsToShow => contactListViewModel.walletContacts .where((element) => element.type == receiveCurrency) .toList(); @action bool checkIfWalletIsAnInternalWallet(String address) { final walletContactList = walletContactsToShow.where((element) => element.address == address).toList(); return walletContactList.isNotEmpty; } @computed bool get shouldDisplayTOTP2FAForExchangesToInternalWallet => _settingsStore.shouldRequireTOTP2FAForExchangesToInternalWallets; @computed bool get shouldDisplayTOTP2FAForExchangesToExternalWallet => _settingsStore.shouldRequireTOTP2FAForExchangesToExternalWallets; //* Still open to further optimize these checks //* It works but can be made better @action bool shouldDisplayTOTP() { final isInternalWallet = checkIfWalletIsAnInternalWallet(receiveAddress); if (isInternalWallet) { return shouldDisplayTOTP2FAForExchangesToInternalWallet; } else { return shouldDisplayTOTP2FAForExchangesToExternalWallet; } } @computed TransactionPriority get transactionPriority { final priority = _settingsStore.priority[wallet.type]; if (priority == null) { throw Exception('Unexpected type ${wallet.type.toString()}'); } return priority; } bool get hasAllAmount => (wallet.type == WalletType.bitcoin || wallet.type == WalletType.litecoin || wallet.type == WalletType.bitcoinCash) && depositCurrency == wallet.currency; bool get isMoneroWallet => wallet.type == WalletType.monero; bool get isLowFee { switch (wallet.type) { case WalletType.monero: case WalletType.haven: return transactionPriority == monero!.getMoneroTransactionPrioritySlow(); case WalletType.bitcoin: return transactionPriority == bitcoin!.getBitcoinTransactionPrioritySlow(); case WalletType.litecoin: return transactionPriority == bitcoin!.getLitecoinTransactionPrioritySlow(); case WalletType.ethereum: return transactionPriority == ethereum!.getEthereumTransactionPrioritySlow(); case WalletType.bitcoinCash: return transactionPriority == bitcoinCash!.getBitcoinCashTransactionPrioritySlow(); case WalletType.polygon: return transactionPriority == polygon!.getPolygonTransactionPrioritySlow(); default: return false; } } List receiveCurrencies; List depositCurrencies; final NumberFormat _cryptoNumberFormat; final SettingsStore _settingsStore; final ContactListViewModel contactListViewModel; double _bestRate = 0.0; late Timer bestRateSync; @action void changeDepositCurrency({required CryptoCurrency currency}) { depositCurrency = currency; isFixedRateMode = false; _onPairChange(); isDepositAddressEnabled = !(depositCurrency == wallet.currency); } @action void changeReceiveCurrency({required CryptoCurrency currency}) { receiveCurrency = currency; isFixedRateMode = false; _onPairChange(); isDepositAddressEnabled = !(depositCurrency == wallet.currency); } @action Future changeReceiveAmount({required String amount}) async { receiveAmount = amount; if (amount.isEmpty) { depositAmount = ''; receiveAmount = ''; return; } final _enteredAmount = double.tryParse(amount.replaceAll(',', '.')) ?? 0; if (_bestRate == 0) { depositAmount = S.current.fetching; await _calculateBestRate(); } _cryptoNumberFormat.maximumFractionDigits = depositMaxDigits; depositAmount = _cryptoNumberFormat .format(_enteredAmount / _bestRate) .toString() .replaceAll(RegExp('\\,'), ''); } @action Future changeDepositAmount({required String amount}) async { depositAmount = amount; if (amount.isEmpty) { depositAmount = ''; receiveAmount = ''; return; } final _enteredAmount = double.tryParse(amount.replaceAll(',', '.')) ?? 0; /// in case the best rate was not calculated yet if (_bestRate == 0) { receiveAmount = S.current.fetching; await _calculateBestRate(); } _cryptoNumberFormat.maximumFractionDigits = receiveMaxDigits; receiveAmount = _cryptoNumberFormat .format(_bestRate * _enteredAmount) .toString() .replaceAll(RegExp('\\,'), ''); } bool checkIfInputMeetsMinOrMaxCondition(String input) { final _enteredAmount = double.tryParse(input.replaceAll(',', '.')) ?? 0; double minLimit = limits.min ?? 0; double? maxLimit = limits.max; if (_enteredAmount < minLimit) return false; if (maxLimit != null && _enteredAmount > maxLimit) return false; return true; } Future _calculateBestRate() async { final amount = double.tryParse(isFixedRateMode ? receiveAmount : depositAmount) ?? 1; final _providers = _tradeAvailableProviders .where((element) => !isFixedRateMode || element.supportsFixedRate) .toList(); final result = await Future.wait(_providers.map((element) => element.fetchRate( from: depositCurrency, to: receiveCurrency, amount: amount, isFixedRateMode: isFixedRateMode, isReceiveAmount: isFixedRateMode))); _sortedAvailableProviders.clear(); for (int i = 0; i < result.length; i++) { if (result[i] != 0) { /// add this provider as its valid for this trade try { _sortedAvailableProviders[result[i]] = _providers[i]; } catch (e) { // will throw "Concurrent modification during iteration" error if modified at the same // time [createTrade] is called, as this is not a normal map, but a sorted map } } } if (_sortedAvailableProviders.isNotEmpty) _bestRate = _sortedAvailableProviders.keys.first; } @action Future loadLimits() async { if (selectedProviders.isEmpty) return; limitsState = LimitsIsLoading(); final from = isFixedRateMode ? receiveCurrency : depositCurrency; final to = isFixedRateMode ? depositCurrency : receiveCurrency; double? lowestMin = double.maxFinite; double? highestMax = 0.0; try { for (var provider in selectedProviders) { /// if this provider is not valid for the current pair, skip it if (!providersForCurrentPair().contains(provider)) continue; try { final tempLimits = await provider.fetchLimits(from: from, to: to, isFixedRateMode: isFixedRateMode); if (lowestMin != null && (tempLimits.min ?? -1) < lowestMin) lowestMin = tempLimits.min; if (highestMax != null && (tempLimits.max ?? double.maxFinite) > highestMax) highestMax = tempLimits.max; } catch (e) { continue; } } } on ConcurrentModificationError { /// if user changed the selected providers while fetching limits /// then delay the fetching limits a bit and try again /// /// this is because the limitation of collections that /// you can't modify it while iterating through it Future.delayed(Duration(milliseconds: 200), loadLimits); } if (lowestMin != double.maxFinite) { limits = Limits(min: lowestMin, max: highestMax); limitsState = LimitsLoadedSuccessfully(limits: limits); } else { limitsState = LimitsLoadedFailure(error: 'Limits loading failed'); } } @action Future createTrade() async { if (isSendAllEnabled) { await calculateDepositAllAmount(); final amount = double.tryParse(depositAmount); if (limits.min != null && amount != null && amount < limits.min!) { tradeState = TradeIsCreatedFailure( title: S.current.trade_not_created, error: S.current.amount_is_below_minimum_limit(limits.min!.toString())); return; } } try { for (var provider in _sortedAvailableProviders.values) { if (!(await provider.checkIsAvailable())) continue; final request = TradeRequest( fromCurrency: depositCurrency, toCurrency: receiveCurrency, fromAmount: depositAmount.replaceAll(',', '.'), toAmount: receiveAmount.replaceAll(',', '.'), refundAddress: depositAddress, toAddress: receiveAddress, isFixedRate: isFixedRateMode); var amount = isFixedRateMode ? receiveAmount : depositAmount; amount = amount.replaceAll(',', '.'); if (limitsState is LimitsLoadedSuccessfully) { if (double.tryParse(amount) == null) continue; if (limits.max != null && double.parse(amount) < limits.min!) continue; else if (limits.max != null && double.parse(amount) > limits.max!) continue; else { try { tradeState = TradeIsCreating(); final trade = await provider.createTrade( request: request, isFixedRateMode: isFixedRateMode, isSendAll: isSendAllEnabled, ); trade.walletId = wallet.id; trade.fromWalletAddress = wallet.walletAddresses.address; final canCreateTrade = await isCanCreateTrade(trade); if (!canCreateTrade.result) { tradeState = TradeIsCreatedFailure( title: S.current.trade_not_created, error: canCreateTrade.errorMessage ?? '', ); return; } tradesStore.setTrade(trade); if (trade.provider != ExchangeProviderDescription.thorChain) await trades.add(trade); tradeState = TradeIsCreatedSuccessfully(trade: trade); /// return after the first successful trade return; } catch (e) { continue; } } } } /// if the code reached here then none of the providers succeeded tradeState = TradeIsCreatedFailure( title: S.current.trade_not_created, error: S.current.none_of_selected_providers_can_exchange); } on ConcurrentModificationError { /// if create trade happened at the exact same time of the scheduled rate update /// then delay the create trade a bit and try again /// /// this is because the limitation of the SplayTreeMap that /// you can't modify it while iterating through it Future.delayed(Duration(milliseconds: 200), createTrade); } } @action void reset() { _initialPairBasedOnWallet(); isReceiveAmountEntered = false; depositAmount = ''; receiveAmount = ''; depositAddress = depositCurrency == wallet.currency ? wallet.walletAddresses.address : ''; receiveAddress = receiveCurrency == wallet.currency ? wallet.walletAddresses.address : ''; isDepositAddressEnabled = !(depositCurrency == wallet.currency); isFixedRateMode = false; _onPairChange(); } @action void enableSendAllAmount() { isSendAllEnabled = true; isFixedRateMode = false; calculateDepositAllAmount(); } @action void enableFixedRateMode() { isSendAllEnabled = false; isFixedRateMode = true; } @action Future calculateDepositAllAmount() async { if (wallet.type == WalletType.litecoin || wallet.type == WalletType.bitcoin || wallet.type == WalletType.bitcoinCash) { final priority = _settingsStore.priority[wallet.type]!; final amount = await bitcoin!.estimateFakeSendAllTxAmount(wallet, priority); changeDepositAmount(amount: bitcoin!.formatterBitcoinAmountToString(amount: amount)); } } void updateTemplate() => _exchangeTemplateStore.update(); void addTemplate( {required String amount, required String depositCurrency, required String receiveCurrency, required String provider, required String depositAddress, required String receiveAddress, required String depositCurrencyTitle, required String receiveCurrencyTitle}) => _exchangeTemplateStore.addTemplate( amount: amount, depositCurrency: depositCurrency, receiveCurrency: receiveCurrency, provider: provider, depositAddress: depositAddress, receiveAddress: receiveAddress, depositCurrencyTitle: depositCurrencyTitle, receiveCurrencyTitle: receiveCurrencyTitle); void removeTemplate({required ExchangeTemplate template}) => _exchangeTemplateStore.remove(template: template); List providersForCurrentPair() => _providersForPair(from: depositCurrency, to: receiveCurrency); List _providersForPair( {required CryptoCurrency from, required CryptoCurrency to}) => providerList .where((provider) => provider.pairList.where((pair) => pair.from == from && pair.to == to).isNotEmpty) .toList(); void _onPairChange() { depositAmount = ''; receiveAmount = ''; loadLimits(); _setAvailableProviders(); _bestRate = 0; _calculateBestRate(); } void _initialPairBasedOnWallet() { switch (wallet.type) { case WalletType.monero: depositCurrency = CryptoCurrency.xmr; receiveCurrency = CryptoCurrency.btc; break; case WalletType.bitcoin: depositCurrency = CryptoCurrency.btc; receiveCurrency = CryptoCurrency.xmr; break; case WalletType.litecoin: depositCurrency = CryptoCurrency.ltc; receiveCurrency = CryptoCurrency.xmr; break; case WalletType.bitcoinCash: depositCurrency = CryptoCurrency.bch; receiveCurrency = CryptoCurrency.xmr; break; case WalletType.haven: depositCurrency = CryptoCurrency.xhv; receiveCurrency = CryptoCurrency.btc; break; case WalletType.ethereum: depositCurrency = CryptoCurrency.eth; receiveCurrency = CryptoCurrency.xmr; break; case WalletType.nano: depositCurrency = CryptoCurrency.nano; receiveCurrency = CryptoCurrency.xmr; break; case WalletType.polygon: depositCurrency = CryptoCurrency.maticpoly; receiveCurrency = CryptoCurrency.xmr; break; case WalletType.solana: depositCurrency = CryptoCurrency.sol; receiveCurrency = CryptoCurrency.xmr; break; case WalletType.tron: depositCurrency = CryptoCurrency.trx; receiveCurrency = CryptoCurrency.xmr; break; default: break; } } void _defineIsReceiveAmountEditable() { /*if ((provider is ChangeNowExchangeProvider) &&(depositCurrency == CryptoCurrency.xmr) &&(receiveCurrency == CryptoCurrency.btc)) { isReceiveAmountEditable = true; } else { isReceiveAmountEditable = false; }*/ //isReceiveAmountEditable = false; // isReceiveAmountEditable = selectedProviders.any((provider) => provider is ChangeNowExchangeProvider); // isReceiveAmountEditable = provider is ChangeNowExchangeProvider || provider is SimpleSwapExchangeProvider; isReceiveAmountEditable = true; } @action void addExchangeProvider(ExchangeProvider provider) { selectedProviders.add(provider); if (providersForCurrentPair().contains(provider)) _tradeAvailableProviders.add(provider); } @action void removeExchangeProvider(ExchangeProvider provider) { selectedProviders.remove(provider); _tradeAvailableProviders.remove(provider); } @action void saveSelectedProviders() { depositAmount = ''; receiveAmount = ''; isFixedRateMode = false; _defineIsReceiveAmountEditable(); loadLimits(); _bestRate = 0; _calculateBestRate(); final Map exchangeProvidersSelection = json.decode(sharedPreferences.getString(PreferencesKey.exchangeProvidersSelection) ?? "{}") as Map; for (var provider in providerList) { exchangeProvidersSelection[provider.title] = selectedProviders.contains(provider); } sharedPreferences.setString( PreferencesKey.exchangeProvidersSelection, json.encode(exchangeProvidersSelection), ); } bool get isAvailableInSelected { final providersForPair = providersForCurrentPair(); return selectedProviders .any((element) => element.isAvailable && providersForPair.contains(element)); } void _setAvailableProviders() { _tradeAvailableProviders.clear(); _tradeAvailableProviders.addAll( selectedProviders.where((provider) => providersForCurrentPair().contains(provider))); } @action void setDefaultTransactionPriority() { switch (wallet.type) { case WalletType.monero: case WalletType.haven: _settingsStore.priority[wallet.type] = monero!.getMoneroTransactionPriorityAutomatic(); break; case WalletType.bitcoin: _settingsStore.priority[wallet.type] = bitcoin!.getBitcoinTransactionPriorityMedium(); break; case WalletType.litecoin: _settingsStore.priority[wallet.type] = bitcoin!.getLitecoinTransactionPriorityMedium(); break; case WalletType.ethereum: _settingsStore.priority[wallet.type] = ethereum!.getDefaultTransactionPriority(); break; case WalletType.bitcoinCash: _settingsStore.priority[wallet.type] = bitcoinCash!.getDefaultTransactionPriority(); break; case WalletType.polygon: _settingsStore.priority[wallet.type] = polygon!.getDefaultTransactionPriority(); break; default: break; } } void _setProviders() { if (_settingsStore.exchangeStatus == ExchangeApiMode.torOnly) providerList = _allProviders.where((provider) => provider.supportsOnionAddress).toList(); else providerList = _allProviders; } int get depositMaxDigits => depositCurrency.decimals; int get receiveMaxDigits => receiveCurrency.decimals; Future isCanCreateTrade(Trade trade) async { if (trade.provider == ExchangeProviderDescription.thorChain) { final payoutAddress = trade.payoutAddress ?? ''; final fromWalletAddress = trade.fromWalletAddress ?? ''; final tapRootPattern = RegExp(P2trAddress.regex.pattern); if (tapRootPattern.hasMatch(payoutAddress) || tapRootPattern.hasMatch(fromWalletAddress)) { return CreateTradeResult( result: false, errorMessage: S.current.thorchain_taproot_address_not_supported, ); } final currenciesToCheckPattern = RegExp('0x[0-9a-zA-Z]'); // Perform checks for payOutAddress final isPayOutAddressAccordingToPattern = currenciesToCheckPattern.hasMatch(payoutAddress); if (isPayOutAddressAccordingToPattern) { final isPayOutAddressEOA = await _isExternallyOwnedAccountAddress(payoutAddress); return CreateTradeResult( result: isPayOutAddressEOA, errorMessage: !isPayOutAddressEOA ? S.current.thorchain_contract_address_not_supported : null, ); } // Perform checks for fromWalletAddress final isFromWalletAddressAddressAccordingToPattern = currenciesToCheckPattern.hasMatch(fromWalletAddress); if (isFromWalletAddressAddressAccordingToPattern) { final isFromWalletAddressEOA = await _isExternallyOwnedAccountAddress(fromWalletAddress); return CreateTradeResult( result: isFromWalletAddressEOA, errorMessage: !isFromWalletAddressEOA ? S.current.thorchain_contract_address_not_supported : null, ); } } return CreateTradeResult(result: true); } String _normalizeReceiveCurrency(CryptoCurrency receiveCurrency) { switch (receiveCurrency) { case CryptoCurrency.eth: return 'eth'; case CryptoCurrency.maticpoly: return 'polygon'; default: return receiveCurrency.tag ?? ''; } } Future _isExternallyOwnedAccountAddress(String receivingAddress) async { final normalizedReceiveCurrency = _normalizeReceiveCurrency(receiveCurrency); final isEOAAddress = !(await _isContractAddress(normalizedReceiveCurrency, receivingAddress)); return isEOAAddress; } Future _isContractAddress(String chainName, String contractAddress) async { final httpClient = http.Client(); final uri = Uri.https( 'deep-index.moralis.io', '/api/v2.2/erc20/metadata', { "chain": chainName, "addresses": contractAddress, }, ); try { final response = await httpClient.get( uri, headers: { "Accept": "application/json", "X-API-Key": secrets.moralisApiKey, }, ); final decodedResponse = jsonDecode(response.body)[0] as Map; final name = decodedResponse['name'] as String?; bool isContractAddress = name!.isNotEmpty; return isContractAddress; } catch (e) { print(e); return false; } } }