CakeWallet/cw_bitcoin/lib/electrum_wallet.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:isolate';

import 'package:bitcoin_base/bitcoin_base.dart';
import 'package:cw_bitcoin/electrum_worker/electrum_worker.dart';
import 'package:cw_bitcoin/seedbyte_types.dart';
import 'package:cw_bitcoin/electrum_worker/electrum_worker_methods.dart';
import 'package:cw_bitcoin/electrum_worker/electrum_worker_params.dart';
import 'package:cw_bitcoin/electrum_worker/methods/methods.dart';
import 'package:cw_bitcoin/wallet_seed_bytes.dart';
import 'package:cw_core/utils/print_verbose.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:blockchain_utils/blockchain_utils.dart';
import 'package:collection/collection.dart';
import 'package:cw_bitcoin/bitcoin_address_record.dart';
import 'package:cw_bitcoin/bitcoin_transaction_credentials.dart';
import 'package:cw_bitcoin/bitcoin_unspent.dart';
import 'package:cw_bitcoin/bitcoin_wallet_keys.dart';
import 'package:cw_bitcoin/electrum_balance.dart';
import 'package:cw_bitcoin/electrum_transaction_history.dart';
import 'package:cw_bitcoin/electrum_transaction_info.dart';
import 'package:cw_bitcoin/electrum_wallet_addresses.dart';
import 'package:cw_bitcoin/exceptions.dart';
import 'package:cw_bitcoin/pending_bitcoin_transaction.dart';
import 'package:cw_core/crypto_currency.dart';
import 'package:cw_core/encryption_file_utils.dart';
import 'package:cw_core/node.dart';
import 'package:cw_core/pathForWallet.dart';
import 'package:cw_core/pending_transaction.dart';
import 'package:cw_core/sync_status.dart';
import 'package:cw_core/transaction_priority.dart';
import 'package:cw_core/unspent_coins_info.dart';
import 'package:cw_core/wallet_base.dart';
import 'package:cw_core/wallet_info.dart';
import 'package:cw_core/wallet_keys_file.dart';
import 'package:flutter/foundation.dart';
import 'package:hive/hive.dart';
import 'package:ledger_flutter_plus/ledger_flutter_plus.dart' as ledger;
import 'package:mobx/mobx.dart';

part 'electrum_wallet.g.dart';

class ElectrumWallet<T extends ElectrumWalletAddresses> = ElectrumWalletBase<T>
    with _$ElectrumWallet<T>;

abstract class ElectrumWalletBase<T extends ElectrumWalletAddresses>
    extends WalletBase<ElectrumBalance, ElectrumTransactionHistory, ElectrumTransactionInfo, T>
    with Store, WalletKeysFile {
  ReceivePort? _receivePort;
  SendPort? workerSendPort;
  StreamSubscription<dynamic>? _workerSubscription;
  Isolate? _workerIsolate;
  final Map<int, dynamic> _responseCompleters = {};
  final Map<int, dynamic> _errorCompleters = {};
  int _messageId = 0;

  static const String SIGN_MESSAGE_PREFIX = '\x18Bitcoin Signed Message:\n';

  ElectrumWalletBase({
    required String password,
    required WalletInfo walletInfo,
    required this.unspentCoinsInfo,
    required this.network,
    required this.encryptionFileUtils,
    required this.hdWallets,
    required CryptoCurrency currency,
    String? xpub,
    String? mnemonic,
    this.passphrase,
    ElectrumBalance? initialBalance,
    List<BitcoinUnspent>? initialUnspentCoins,
  })  : _xpub = xpub,
        _syncStatus = NotConnectedSyncStatus(),
        _password = password,
        isEnabledAutoGenerateSubaddress = true,
        unspentCoins = ElectrumUnspentCoins.of(initialUnspentCoins ?? []),
        balance = ObservableMap<CryptoCurrency, ElectrumBalance>.of({
          currency: initialBalance ??
              ElectrumBalance(
                confirmed: 0,
                unconfirmed: 0,
                frozen: 0,
              )
        }),
        this.isTestnet = !network.isMainnet,
        this._mnemonic = mnemonic,
        super(walletInfo) {
    transactionHistory = ElectrumTransactionHistory(
      walletInfo: walletInfo,
      password: password,
      encryptionFileUtils: encryptionFileUtils,
    );

    reaction((_) => syncStatus, syncStatusReaction);

    sharedPrefs.complete(SharedPreferences.getInstance());
  }

  static Future<Map<SeedBytesType, Bip32Slip10Secp256k1>> getAccountHDWallets({
    required WalletInfo walletInfo,
    required BasedUtxoNetwork network,
    String? mnemonic,
    String? passphrase,
    String? xpub,
  }) async {
    assert(
      mnemonic != null || xpub != null,
      "To create a Wallet you need either a seed or an xpub. This should not happen",
    );

    late WalletSeedData walletSeedData;
    if (mnemonic != null) {
      walletSeedData = await WalletSeedData.fromMnemonic(walletInfo, mnemonic, network, passphrase);
    } else {
      walletSeedData = WalletSeedData.fromXpub(walletInfo, xpub!, network);
    }

    return walletSeedData.hdWallets;
  }

  // Sends a request to the worker and does not wait for a response
  Null sendWorker(ElectrumWorkerRequest request) {
    workerSendPort!.send(request.toJson());
    return null;
  }

  // Sends a request to the worker and returns a future that completes when the worker responds
  Future<T> waitSendWorker<T extends Map<String, dynamic>>(
    ElectrumWorkerRequest request, [
    Duration timeout = const Duration(seconds: 30),
  ]) async {
    final messageId = ++_messageId;

    final completer = Completer<T>();
    _responseCompleters[messageId] = completer;

    final m = request.toJson();
    m['id'] = messageId;
    workerSendPort!.send(m);

    try {
      return await completer.future.timeout(timeout);
    } catch (e) {
      _errorCompleters[messageId] = e;
      _responseCompleters.remove(messageId);
      rethrow;
    }
  }

  @action
  Future<void> handleWorkerResponse(dynamic message) async {
    // printV('Main: received message: $message');

    Map<String, dynamic> messageJson;
    if (message is String) {
      messageJson = jsonDecode(message) as Map<String, dynamic>;
    } else {
      messageJson = message as Map<String, dynamic>;
    }

    final workerMethod = messageJson['method'] as String;
    final workerError = messageJson['error'] as String?;
    final responseId = messageJson['id'] as int?;
    final completed = messageJson['completed'] as bool?;

    switch (workerMethod) {
      case ElectrumWorkerMethods.connectionMethod:
        if (workerError != null) {
          _onConnectionStatusChange(ConnectionStatus.failed);
          break;
        }

        final response = ElectrumWorkerConnectionResponse.fromJson(messageJson);
        _onConnectionStatusChange(response.result);
        break;
      case ElectrumRequestMethods.headersSubscribeMethod:
        final response = ElectrumWorkerHeadersSubscribeResponse.fromJson(messageJson);
        await onHeadersResponse(response.result);
        break;
      case ElectrumRequestMethods.scripthashesSubscribeMethod:
        final response = ElectrumWorkerScripthashesSubscribeResponse.fromJson(messageJson);
        await onScripthashesStatusResponse(response.result);
        break;
      case ElectrumRequestMethods.getBalanceMethod:
        final response = ElectrumWorkerGetBalanceResponse.fromJson(messageJson);
        onBalanceResponse(response.result);
        break;
      case ElectrumRequestMethods.getHistoryMethod:
        onHistoriesResponse(ElectrumWorkerGetHistoryResponse.fromJson(messageJson));
        break;
      case ElectrumRequestMethods.listunspentMethod:
        final response = ElectrumWorkerListUnspentResponse.fromJson(messageJson);
        onUnspentResponse(response.result);
        break;
      case ElectrumRequestMethods.estimateFeeMethod:
        final response = ElectrumWorkerGetFeesResponse.fromJson(messageJson);
        onFeesResponse(response.result);
        break;
      case ElectrumWorkerMethods.discoverAddressesMethod:
        final response = ElectrumWorkerDiscoverAddressesResponse.fromJson(messageJson);
        _onAddressesDiscovered(response.result);
        break;
    }

    final shouldComplete = workerError != null || completed == true;

    if (shouldComplete && responseId != null && _responseCompleters.containsKey(responseId)) {
      _responseCompleters[responseId]!.complete(messageJson);
      _responseCompleters.remove(responseId);
    }
  }

  int estimatedTransactionSize({
    required List<BitcoinAddressType> inputTypes,
    required List<BitcoinAddressType> outputTypes,
    String? memo,
    bool enableRBF = true,
  }) =>
      BitcoinTransactionBuilder.estimateTransactionSizeFromTypes(
        inputTypes: inputTypes,
        outputTypes: outputTypes,
        network: network,
        memo: memo,
        enableRBF: enableRBF,
      );

  final Map<SeedBytesType, Bip32Slip10Secp256k1> hdWallets;
  Bip32Slip10Secp256k1 get hdWallet =>
      hdWallets[SeedBytesType.bip39] ?? hdWallets[SeedBytesType.electrum]!;
  final String? _mnemonic;

  final EncryptionFileUtils encryptionFileUtils;

  @override
  final String? passphrase;

  @override
  @observable
  bool isEnabledAutoGenerateSubaddress;

  Box<UnspentCoinsInfo> unspentCoinsInfo;

  @override
  late T walletAddresses;

  @override
  @observable
  late ObservableMap<CryptoCurrency, ElectrumBalance> balance;

  @observable
  SyncStatus _syncStatus;

  @override
  @computed
  SyncStatus get syncStatus => _syncStatus;

  @observable
  bool syncStatusLock = false;

  @override
  set syncStatus(SyncStatus value) {
    _syncStatus = value;
  }

  final String? _xpub;
  String get xpub => _xpub ?? hdWallet.publicKey.toExtended;

  @override
  String? get seed => _mnemonic;

  @override
  WalletKeysData get walletKeysData => WalletKeysData(
        mnemonic: _mnemonic,
        xPub: xpub,
        passphrase: passphrase,
      );

  @override
  String get password => _password;

  BasedUtxoNetwork network;

  // TODO: change from isTestnet boolean to a networks enum (regtest, signet, etc)
  @override
  bool isTestnet;

  bool _isTryingToConnect = false;

  Completer<SharedPreferences> sharedPrefs = Completer();

  @observable
  int? currentChainTip;

  @override
  BitcoinWalletKeys get keys => BitcoinWalletKeys(
        wif: WifEncoder.encode(hdWallet.privateKey.raw, netVer: network.wifNetVer),
        privateKey: hdWallet.privateKey.toHex(),
        publicKey: hdWallet.publicKey.toHex(),
      );

  String _password;

  ElectrumUnspentCoins unspentCoins;

  @observable
  TransactionPriorities? feeRates;

  int feeRate(TransactionPriority priority) => feeRates![priority];

  @observable
  // NOTE: https://electrumx.readthedocs.io/en/latest/protocol-basics.html#status
  List<String> scripthashesWithStatus = [];

  bool _chainTipListenerOn = false;

  void Function(FlutterErrorDetails)? _onError;
  Timer? _autoSaveTimer;
  static const int _autoSaveInterval = 1;

  Future<InitAddressesData> initAddresses([bool? sync]) async {
    bool? isDiscovered = null;
    bool? discovered;

    // NOTE: will initiate by priority from the first walletAddressTypes
    // then proceeds to following ones after got fully discovered response from worker response
    for (final addressType in walletAddresses.walletAddressTypes) {
      if (currency == CryptoCurrency.btc &&
          isHardwareWallet &&
          addressType != SegwitAddressType.p2wpkh) continue;

      final bitcoinDerivationInfo = BitcoinAddressUtils.getDerivationFromType(
        addressType,
        network: network,
        isElectrum: walletAddresses.walletSeedBytesType.isElectrum,
      );

      for (final isChange in [true, false]) {
        isDiscovered = walletAddresses.discoveredAddressesRecord.getIsDiscovered(
          addressType: addressType,
          seedBytesType: walletAddresses.walletSeedBytesType,
          derivationPath: bitcoinDerivationInfo.derivationPath.toString(),
          isChange: isChange,
        );

        if (isDiscovered == false) break;
      }

      if (isDiscovered == false) {
        discovered = await generateInitialAddresses(
          addressType: addressType,
          seedBytesType: walletAddresses.walletSeedBytesType,
          bitcoinDerivationInfo: bitcoinDerivationInfo,
        );
        break;
      }
    }

    if (currency != CryptoCurrency.btc) {
      for (final addressType in walletAddresses.walletAddressTypes) {
        for (final seedBytesType in hdWallets.keys) {
          final bitcoinDerivationInfo = BitcoinAddressUtils.getDerivationFromType(
            addressType,
            network: network,
            isElectrum: seedBytesType.isElectrum,
          );

          bool alreadyDidDerivation = false;

          for (final derivationInfo in [
            bitcoinDerivationInfo,
            BitcoinDerivationInfos.BIP84,
            BitcoinDerivationInfos.ELECTRUM,
          ]) {
            final derivationPath = derivationInfo.derivationPath.toString();

            if (alreadyDidDerivation &&
                derivationPath == bitcoinDerivationInfo.derivationPath.toString()) {
              continue;
            }

            alreadyDidDerivation = true;

            for (final isChange in [true, false]) {
              isDiscovered = walletAddresses.discoveredAddressesRecord.getIsDiscovered(
                addressType: addressType,
                seedBytesType: seedBytesType,
                derivationPath: derivationPath,
                isChange: isChange,
              );

              if (isDiscovered == false) {
                break;
              } else if (sync == true)
                subscribeForStatuses(
                  walletAddresses.addressesRecords
                      .getRecords(
                        addressType: addressType,
                        seedBytesType: seedBytesType,
                        derivationPath: derivationPath,
                        isChange: isChange,
                      )
                      .whereType<BitcoinAddressRecord>()
                      .toList(),
                );
            }

            if (isDiscovered == false) {
              discovered = await generateInitialAddresses(
                addressType: addressType,
                seedBytesType: seedBytesType,
                bitcoinDerivationInfo: derivationInfo,
              );
              break;
            }
          }

          if (isDiscovered == false) break;
        }

        if (isDiscovered == false) break;
      }

      if (isDiscovered == true && sync == false)
        initAddresses(true);
      else if (isDiscovered == false && discovered == false) initAddresses(sync);
    }

    if (isDiscovered == true && syncStatus is SynchronizingSyncStatus)
      syncStatus = SyncedSyncStatus();

    return InitAddressesData(
      isDiscovered: isDiscovered,
      discovered: discovered,
    );
  }

  Future<void> init() async {
    await walletAddresses.init();
    await transactionHistory.init();

    _autoSaveTimer =
        Timer.periodic(Duration(minutes: _autoSaveInterval), (_) async => await save());
  }

  @action
  @override
  Future<void> startSync() async {
    try {
      syncStatus = SynchronizingSyncStatus();

      unspentCoins.removeWhere((utxo) => utxo.bitcoinAddressRecord is BitcoinAddressRecord);

      await subscribeForHeaders(true);
      await updateFeeRates();

      await initAddresses(false);

      await save();
    } catch (e, stacktrace) {
      printV(stacktrace);
      printV("startSync $e");
      syncStatus = FailedSyncStatus();
    }
  }

  @action
  void callError(FlutterErrorDetails error) {
    _onError?.call(error);
  }

  Future<void> updateFeeRates() async {
    workerSendPort!.send(ElectrumWorkerGetFeesRequest().toJson());
  }

  @action
  Future<void> onFeesResponse(TransactionPriorities? result) async {
    if (result != null) {
      feeRates = result;
    }
  }

  Node? node;

  @action
  @override
  Future<void> connectToNode({required Node node}) async {
    this.node = node;

    try {
      syncStatus = ConnectingSyncStatus();

      if (_workerIsolate != null) {
        _workerIsolate!.kill(priority: Isolate.immediate);
        _workerSubscription?.cancel();
        _receivePort?.close();
      }

      _receivePort = ReceivePort();

      _workerIsolate = await Isolate.spawn<SendPort>(ElectrumWorker.run, _receivePort!.sendPort);

      _workerSubscription = _receivePort!.listen((message) {
        if (message is SendPort) {
          workerSendPort = message;
          workerSendPort!.send(
            ElectrumWorkerConnectionRequest(
              uri: node.uri,
              useSSL: node.useSSL ?? false,
              network: network,
              walletType: walletInfo.type,
            ).toJson(),
          );
        } else {
          handleWorkerResponse(message);
        }
      });
    } catch (e, stacktrace) {
      printV(stacktrace);
      printV("connectToNode $e");
      syncStatus = FailedSyncStatus();
    }
  }

  int get dustAmount => 546;

  bool isBelowDust(int amount) => amount <= dustAmount;

  ElectrumTxCreateUtxoDetails createUTXOS({
    required bool sendAll,
    int credentialsAmount = 0,
    int? inputsCount,
  }) {
    List<UtxoWithAddress> utxos = [];
    List<Outpoint> vinOutpoints = [];
    List<ECPrivateInfo> inputPrivKeyInfos = [];
    final publicKeys = <String, PublicKeyWithDerivationPath>{};
    int allInputsAmount = 0;
    bool spendsUnconfirmedTX = false;

    int leftAmount = credentialsAmount;
    var availableInputs = unspentCoins.where((utx) {
      final unspentCoinInfo = unspentCoinsInfo.values.firstWhereOrNull(
        (element) => element.walletId == id && element == utx,
      );

      if (!utx.isSending || utx.isFrozen) {
        return false;
      }
      if (unspentCoinInfo != null) {
        if (!unspentCoinInfo.isSending || unspentCoinInfo.isFrozen) {
          return false;
        }
      }
      return true;
    }).toList();
    final unconfirmedCoins = availableInputs.where((utx) => utx.confirmations == 0).toList();

    for (int i = 0; i < availableInputs.length; i++) {
      final utx = availableInputs[i];
      if (!spendsUnconfirmedTX) spendsUnconfirmedTX = utx.confirmations == 0;

      allInputsAmount += utx.value;
      leftAmount = leftAmount - utx.value;

      final address = RegexUtils.addressTypeFromStr(utx.address, network);
      ECPrivate? privkey;

      if (!isHardwareWallet) {
        final addressRecord = utx.bitcoinAddressRecord;

        privkey = ECPrivate.fromBip32(
          bip32: hdWallets[addressRecord.seedBytesType]!.derive(
            Bip32PathParser.parse(addressRecord.indexedDerivationPath),
          ),
        );
      }

      vinOutpoints.add(Outpoint(txid: utx.hash, index: utx.vout));
      String pubKeyHex;

      if (privkey != null) {
        inputPrivKeyInfos.add(ECPrivateInfo(privkey, address.type == SegwitAddressType.p2tr));

        pubKeyHex = privkey.getPublic().toHex();
      } else {
        pubKeyHex = walletAddresses.hdWallet
            .childKey(Bip32KeyIndex(utx.bitcoinAddressRecord.index))
            .publicKey
            .toHex();
      }

      if (utx.bitcoinAddressRecord is BitcoinAddressRecord) {
        final derivationPath = utx.bitcoinAddressRecord.indexedDerivationPath;
        publicKeys[address.pubKeyHash()] = PublicKeyWithDerivationPath(pubKeyHex, derivationPath);
      }

      utxos.add(
        UtxoWithAddress(
          utxo: BitcoinUtxo(
            txHash: utx.hash,
            value: BigInt.from(utx.value),
            vout: utx.vout,
            scriptType: BitcoinAddressUtils.getScriptType(address),
          ),
          ownerDetails: UtxoAddressDetails(
            publicKey: pubKeyHex,
            address: address,
          ),
        ),
      );

      // sendAll continues for all inputs
      if (!sendAll) {
        bool amountIsAcquired = leftAmount <= 0;
        if ((inputsCount == null && amountIsAcquired) || inputsCount == i + 1) {
          break;
        }
      }
    }

    if (utxos.isEmpty) {
      throw BitcoinTransactionNoInputsException();
    }

    return ElectrumTxCreateUtxoDetails(
      availableInputs: availableInputs,
      unconfirmedCoins: unconfirmedCoins,
      utxos: utxos,
      vinOutpoints: vinOutpoints,
      inputPrivKeyInfos: inputPrivKeyInfos,
      publicKeys: publicKeys,
      allInputsAmount: allInputsAmount,
      spendsUnconfirmedTX: spendsUnconfirmedTX,
    );
  }

  Future<ElectrumEstimatedTx> estimateSendAllTx(
    List<BitcoinOutput> outputs,
    int feeRate, {
    String? memo,
  }) async {
    final utxoDetails = createUTXOS(sendAll: true);

    int fee = await calcFee(
      utxos: utxoDetails.utxos,
      outputs: outputs,
      memo: memo,
      feeRate: feeRate,
    );

    if (fee == 0) {
      throw BitcoinTransactionNoFeeException();
    }

    // Here, when sending all, the output amount equals to the input value - fee to fully spend every input on the transaction and have no amount left for change
    int amount = utxoDetails.allInputsAmount - fee;

    if (amount <= 0) {
      throw BitcoinTransactionWrongBalanceException(amount: utxoDetails.allInputsAmount + fee);
    }

    // Attempting to send less than the dust limit
    if (isBelowDust(amount)) {
      throw BitcoinTransactionNoDustException();
    }

    if (outputs.length == 1) {
      outputs[0] = BitcoinOutput(address: outputs.last.address, value: BigInt.from(amount));
    }

    return ElectrumEstimatedTx(
      utxos: utxoDetails.utxos,
      inputPrivKeyInfos: utxoDetails.inputPrivKeyInfos,
      publicKeys: utxoDetails.publicKeys,
      fee: fee,
      amount: amount,
      isSendAll: true,
      hasChange: false,
      memo: memo,
      spendsUnconfirmedTX: utxoDetails.spendsUnconfirmedTX,
    );
  }

  Future<ElectrumEstimatedTx> estimateTxForAmount(
    int credentialsAmount,
    List<BitcoinOutput> outputs,
    int feeRate, {
    int? inputsCount,
    String? memo,
    bool? useUnconfirmed,
    bool isFakeTx = false,
  }) async {
    // Attempting to send less than the dust limit
    if (!isFakeTx && isBelowDust(credentialsAmount)) {
      throw BitcoinTransactionNoDustException();
    }

    final utxoDetails = createUTXOS(
      sendAll: false,
      credentialsAmount: credentialsAmount,
      inputsCount: inputsCount,
    );

    final spendingAllCoins = utxoDetails.availableInputs.length == utxoDetails.utxos.length;
    final spendingAllConfirmedCoins = !utxoDetails.spendsUnconfirmedTX &&
        utxoDetails.utxos.length ==
            utxoDetails.availableInputs.length - utxoDetails.unconfirmedCoins.length;

    // How much is being spent - how much is being sent
    int amountLeftForChangeAndFee = utxoDetails.allInputsAmount - credentialsAmount;

    if (amountLeftForChangeAndFee <= 0) {
      if (!spendingAllCoins) {
        return estimateTxForAmount(
          credentialsAmount,
          outputs,
          feeRate,
          inputsCount: utxoDetails.utxos.length + 1,
          memo: memo,
          isFakeTx: isFakeTx,
        );
      }

      throw BitcoinTransactionWrongBalanceException();
    }

    final changeAddress = await walletAddresses.getChangeAddress();
    final address = RegexUtils.addressTypeFromStr(changeAddress.address, network);
    outputs.add(BitcoinOutput(
      address: address,
      value: BigInt.from(amountLeftForChangeAndFee),
      isChange: true,
    ));

    final changeDerivationPath = changeAddress.indexedDerivationPath.toString();
    utxoDetails.publicKeys[address.pubKeyHash()] =
        PublicKeyWithDerivationPath('', changeDerivationPath);

    int fee = calcFee(
      utxos: utxoDetails.utxos,
      outputs: outputs,
      memo: memo,
      feeRate: feeRate,
    );

    if (fee == 0) {
      throw BitcoinTransactionNoFeeException();
    }

    int amount = credentialsAmount;
    final lastOutput = outputs.last;
    final amountLeftForChange = amountLeftForChangeAndFee - fee;

    if (!isFakeTx && isBelowDust(amountLeftForChange)) {
      // If has change that is lower than dust, will end up with tx rejected by network rules
      // so remove the change amount
      outputs.removeLast();

      if (amountLeftForChange < 0) {
        if (!spendingAllCoins) {
          return estimateTxForAmount(
            credentialsAmount,
            outputs,
            feeRate,
            inputsCount: utxoDetails.utxos.length + 1,
            memo: memo,
            useUnconfirmed: useUnconfirmed ?? spendingAllConfirmedCoins,
            isFakeTx: isFakeTx,
          );
        } else {
          throw BitcoinTransactionWrongBalanceException();
        }
      }

      return ElectrumEstimatedTx(
        utxos: utxoDetails.utxos,
        inputPrivKeyInfos: utxoDetails.inputPrivKeyInfos,
        publicKeys: utxoDetails.publicKeys,
        fee: fee,
        amount: amount,
        hasChange: false,
        isSendAll: spendingAllCoins,
        memo: memo,
        spendsUnconfirmedTX: utxoDetails.spendsUnconfirmedTX,
      );
    } else {
      // Here, lastOutput already is change, return the amount left without the fee to the user's address.
      outputs[outputs.length - 1] = BitcoinOutput(
        address: lastOutput.address,
        value: BigInt.from(amountLeftForChange),
        isChange: true,
      );

      return ElectrumEstimatedTx(
        utxos: utxoDetails.utxos,
        inputPrivKeyInfos: utxoDetails.inputPrivKeyInfos,
        publicKeys: utxoDetails.publicKeys,
        fee: fee,
        amount: amount,
        hasChange: true,
        isSendAll: spendingAllCoins,
        memo: memo,
        spendsUnconfirmedTX: utxoDetails.spendsUnconfirmedTX,
      );
    }
  }

  int calcFee({
    required List<UtxoWithAddress> utxos,
    required List<BitcoinBaseOutput> outputs,
    String? memo,
    required int feeRate,
  }) =>
      feeRate *
      BitcoinTransactionBuilder.estimateTransactionSize(
        utxos: utxos,
        outputs: outputs,
        network: network,
        memo: memo,
      );

  CreateTxData getCreateTxDataFromCredentials(Object credentials) {
    final outputs = <BitcoinOutput>[];
    final transactionCredentials = credentials as BitcoinTransactionCredentials;
    final hasMultiDestination = transactionCredentials.outputs.length > 1;
    final sendAll = !hasMultiDestination && transactionCredentials.outputs.first.sendAll;
    final memo = transactionCredentials.outputs.first.memo;

    int credentialsAmount = 0;

    for (final out in transactionCredentials.outputs) {
      final outputAmount = out.formattedCryptoAmount!;

      if (!sendAll && isBelowDust(outputAmount)) {
        throw BitcoinTransactionNoDustException();
      }

      if (hasMultiDestination) {
        if (out.sendAll) {
          throw BitcoinTransactionWrongBalanceException();
        }
      }

      credentialsAmount += outputAmount;

      final address = RegexUtils.addressTypeFromStr(
        out.isParsedAddress ? out.extractedAddress! : out.address,
        network,
      );

      if (sendAll) {
        outputs.add(
          BitcoinOutput(
            address: address,
            // Send all: The value of the single existing output will be updated
            // after estimating the Tx size and deducting the fee from the total to be sent
            value: BigInt.from(0),
          ),
        );
      } else {
        outputs.add(
          BitcoinOutput(
            address: address,
            value: BigInt.from(outputAmount),
          ),
        );
      }
    }

    final feeRateInt = transactionCredentials.feeRate != null
        ? transactionCredentials.feeRate!
        : feeRate(transactionCredentials.priority!);

    return CreateTxData(
      sendAll: sendAll,
      amount: credentialsAmount,
      outputs: outputs,
      feeRate: feeRateInt,
      memo: memo,
    );
  }

  @override
  Future<PendingTransaction> createTransaction(Object credentials) async {
    try {
      final data = getCreateTxDataFromCredentials(credentials);

      ElectrumEstimatedTx estimatedTx;
      if (data.sendAll) {
        estimatedTx = await estimateSendAllTx(
          data.outputs,
          data.feeRate,
          memo: data.memo,
        );
      } else {
        estimatedTx = await estimateTxForAmount(
          data.amount,
          data.outputs,
          data.feeRate,
          memo: data.memo,
        );
      }

      if (walletInfo.isHardwareWallet) {
        final transaction = await buildHardwareWalletTransaction(
          utxos: estimatedTx.utxos,
          outputs: data.outputs,
          publicKeys: estimatedTx.publicKeys,
          fee: BigInt.from(estimatedTx.fee),
          memo: estimatedTx.memo,
          outputOrdering: BitcoinOrdering.none,
          enableRBF: true,
        );

        return PendingBitcoinTransaction(
          transaction,
          type,
          waitSendWorker: waitSendWorker,
          amount: estimatedTx.amount,
          fee: estimatedTx.fee,
          feeRate: data.feeRate.toString(),
          hasChange: estimatedTx.hasChange,
          isSendAll: estimatedTx.isSendAll,
          hasTaprootInputs: false, // ToDo: (Konsti) Support Taproot
        )..addListener((transaction) async {
            transactionHistory.addOne(transaction);
            await updateBalance();
            await updateAllUnspents();
          });
      }

      BasedBitcoinTransacationBuilder txb;
      if (network is BitcoinCashNetwork) {
        txb = ForkedTransactionBuilder(
          utxos: estimatedTx.utxos,
          outputs: data.outputs,
          fee: BigInt.from(estimatedTx.fee),
          network: network,
          memo: estimatedTx.memo,
          outputOrdering: BitcoinOrdering.none,
          enableRBF: !estimatedTx.spendsUnconfirmedTX,
        );
      } else {
        txb = BitcoinTransactionBuilder(
          utxos: estimatedTx.utxos,
          outputs: data.outputs,
          fee: BigInt.from(estimatedTx.fee),
          network: network,
          memo: estimatedTx.memo,
          outputOrdering: BitcoinOrdering.none,
          enableRBF: !estimatedTx.spendsUnconfirmedTX,
        );
      }

      bool hasTaprootInputs = false;

      final transaction = txb.buildTransaction((txDigest, utxo, publicKey, sighash) {
        String error = "Cannot find private key.";

        ECPrivateInfo? key;

        if (estimatedTx.inputPrivKeyInfos.isEmpty) {
          error += "\nNo private keys generated.";
        } else {
          error += "\nAddress: ${utxo.ownerDetails.address.toAddress(network)}";

          key = estimatedTx.inputPrivKeyInfos.firstWhereOrNull((element) {
            final elemPubkey = element.privkey.getPublic().toHex();
            if (elemPubkey == publicKey) {
              return true;
            } else {
              error += "\nExpected: $publicKey";
              error += "\nPubkey: $elemPubkey";
              return false;
            }
          });
        }

        if (key == null) {
          throw Exception(error);
        }

        if (utxo.utxo.isP2tr) {
          hasTaprootInputs = true;
          return key.privkey.signTapRoot(txDigest, sighash: sighash);
        } else {
          return key.privkey.signInput(txDigest, sigHash: sighash);
        }
      });

      return PendingBitcoinTransaction(
        transaction,
        type,
        waitSendWorker: waitSendWorker,
        amount: estimatedTx.amount,
        fee: estimatedTx.fee,
        feeRate: data.feeRate.toString(),
        hasChange: estimatedTx.hasChange,
        isSendAll: estimatedTx.isSendAll,
        hasTaprootInputs: hasTaprootInputs,
        utxos: estimatedTx.utxos,
      )..addListener((transaction) async {
          transactionHistory.addOne(transaction);

          unspentCoins
              .removeWhere((utxo) => estimatedTx.utxos.any((e) => e.utxo.txHash == utxo.hash));

          await updateBalance();
          await updateAllUnspents();
        });
    } catch (e) {
      throw e;
    }
  }

  void setLedgerConnection(ledger.LedgerConnection connection) => throw UnimplementedError();

  Future<BtcTransaction> buildHardwareWalletTransaction({
    required List<BitcoinBaseOutput> outputs,
    required BigInt fee,
    required List<UtxoWithAddress> utxos,
    required Map<String, PublicKeyWithDerivationPath> publicKeys,
    String? memo,
    bool enableRBF = false,
    BitcoinOrdering inputOrdering = BitcoinOrdering.bip69,
    BitcoinOrdering outputOrdering = BitcoinOrdering.bip69,
  }) async =>
      throw UnimplementedError();

  String toJSON() => json.encode({
        'mnemonic': _mnemonic,
        'xpub': xpub,
        'passphrase': passphrase ?? '',
        'walletAddresses': walletAddresses.toJson(),
        'balance': balance[currency]?.toJSON(),
        'unspent_coins': unspentCoins.map((e) => e.toJson()).toList(),
      });

  int feeAmountForPriority(
    TransactionPriority priority, {
    required List<BitcoinAddressType> inputTypes,
    required List<BitcoinAddressType> outputTypes,
    String? memo,
    bool enableRBF = true,
  }) =>
      feeRate(priority) *
      estimatedTransactionSize(
        inputTypes: inputTypes,
        outputTypes: outputTypes,
        memo: memo,
        enableRBF: enableRBF,
      );

  int feeAmountWithFeeRate(
    int feeRate, {
    required List<BitcoinAddressType> inputTypes,
    required List<BitcoinAddressType> outputTypes,
    String? memo,
    bool enableRBF = true,
  }) =>
      feeRate *
      estimatedTransactionSize(
        inputTypes: inputTypes,
        outputTypes: outputTypes,
        memo: memo,
        enableRBF: enableRBF,
      );

  @override
  Future<int> calculateEstimatedFee(
    TransactionPriority priority, {
    List<String> outputAddresses = const [],
    String? memo,
    bool enableRBF = true,
  }) async {
    return estimatedFeeForOutputsWithFeeRate(
      feeRate: feeRate(priority),
      outputAddresses: outputAddresses,
      memo: memo,
      enableRBF: enableRBF,
    );
  }

  // Estimates the fee for paying to the given outputs
  // using the wallet's available unspent coins as inputs
  Future<int> estimatedFeeForOutputsWithFeeRate({
    required int feeRate,
    required List<String> outputAddresses,
    String? memo,
    bool enableRBF = true,
  }) async {
    final fakePublicKey = ECPrivate.random().getPublic();
    final fakeOutputs = <BitcoinOutput>[];
    final outputTypes =
        outputAddresses.map((e) => BitcoinAddressUtils.addressTypeFromStr(e, network)).toList();

    for (final outputType in outputTypes) {
      late BitcoinBaseAddress address;
      switch (outputType) {
        case P2pkhAddressType.p2pkh:
          address = fakePublicKey.toP2pkhAddress();
          break;
        case P2shAddressType.p2pkInP2sh:
          address = fakePublicKey.toP2pkhInP2sh();
          break;
        case SegwitAddressType.p2wpkh:
          address = fakePublicKey.toP2wpkhAddress();
          break;
        case P2shAddressType.p2pkhInP2sh:
          address = fakePublicKey.toP2pkhInP2sh();
          break;
        case SegwitAddressType.p2wsh:
          address = fakePublicKey.toP2wshAddress();
          break;
        case SegwitAddressType.p2tr:
        case SilentPaymentsAddresType.p2sp:
          address = fakePublicKey.toTaprootAddress();
          break;
        case SegwitAddressType.mweb:
          address = fakePublicKey.toMwebAddress();
          break;
        default:
          throw const FormatException('Invalid output type');
      }

      fakeOutputs.add(BitcoinOutput(address: address, value: BigInt.from(0)));
    }

    final estimatedFakeTx = await estimateTxForAmount(
      0,
      fakeOutputs,
      feeRate,
      memo: memo,
      isFakeTx: true,
    );
    final inputTypes = estimatedFakeTx.utxos.map((e) => e.ownerDetails.address.type).toList();

    return feeAmountWithFeeRate(
      feeRate,
      inputTypes: inputTypes,
      outputTypes: outputTypes,
      memo: memo,
      enableRBF: enableRBF,
    );
  }

  @override
  Future<void> save() async {
    if (!(await WalletKeysFile.hasKeysFile(walletInfo.name, walletInfo.type))) {
      await saveKeysFile(_password, encryptionFileUtils);
      await saveKeysFile(_password, encryptionFileUtils, true);
    }

    final path = await makePath();
    await encryptionFileUtils.write(path: path, password: _password, data: toJSON());
    await transactionHistory.save();
  }

  @override
  Future<void> renameWalletFiles(String newWalletName) async {
    final currentWalletPath = await pathForWallet(name: walletInfo.name, type: type);
    final currentWalletFile = File(currentWalletPath);

    final currentDirPath = await pathForWalletDir(name: walletInfo.name, type: type);
    final currentTransactionsFile = File('$currentDirPath/$transactionsHistoryFileName');

    // Copies current wallet files into new wallet name's dir and files
    if (currentWalletFile.existsSync()) {
      final newWalletPath = await pathForWallet(name: newWalletName, type: type);
      await currentWalletFile.copy(newWalletPath);
    }
    if (currentTransactionsFile.existsSync()) {
      final newDirPath = await pathForWalletDir(name: newWalletName, type: type);
      await currentTransactionsFile.copy('$newDirPath/$transactionsHistoryFileName');
    }

    // Delete old name's dir and files
    await Directory(currentDirPath).delete(recursive: true);
  }

  @override
  Future<void> changePassword(String password) async {
    _password = password;
    await save();
    await transactionHistory.changePassword(password);
  }

  @override
  Future<void> rescan({required int height}) async {
    throw UnimplementedError();
  }

  @override
  Future<void> close({bool shouldCleanup = false}) async {
    try {
      _workerIsolate!.kill(priority: Isolate.immediate);
      await _workerSubscription?.cancel();
      _receivePort?.close();
    } catch (_) {}
    _autoSaveTimer?.cancel();
  }

  @action
  Future<ElectrumWorkerListUnspentResponse?> updateAllUnspents([
    List<String>? scripthashes,
    bool? wait,
  ]) async {
    scripthashes ??= walletAddresses.allScriptHashes;

    if (scripthashes.isEmpty) {
      return null;
    }

    if (wait == true) {
      return ElectrumWorkerListUnspentResponse.fromJson(
        await waitSendWorker(
          ElectrumWorkerListUnspentRequest(scripthashes: scripthashes.toList()),
        ),
      );
    } else {
      return sendWorker(
        ElectrumWorkerListUnspentRequest(scripthashes: scripthashes.toList()),
      );
    }
  }

  @action
  void updateCoin(BitcoinUnspent coin) {
    final coinInfoList = unspentCoinsInfo.values.where(
      (element) =>
          element.walletId.contains(id) &&
          element.hash.contains(coin.hash) &&
          element.vout == coin.vout,
    );

    if (coinInfoList.isNotEmpty) {
      final coinInfo = coinInfoList.first;

      coin.isFrozen = coinInfo.isFrozen;
      coin.isSending = coinInfo.isSending;
      coin.note = coinInfo.note;
    } else {
      addCoinInfo(coin);
    }
  }

  @action
  Future<void> onUnspentResponse(Map<String, List<ElectrumUtxo>> unspents) async {
    final updatedUnspentCoins = <BitcoinUnspent>[];

    await Future.wait(unspents.entries.map((entry) async {
      final scriptHash = entry.key;
      final unspent = entry.value;

      final addressRecord = walletAddresses.allAddresses.firstWhereOrNull(
        (element) => element.scriptHash == scriptHash,
      );

      if (addressRecord == null) {
        return null;
      }

      if (unspent.isEmpty) {
        unspentCoins.removeWhere((coin) =>
            coin.bitcoinAddressRecord is BitcoinAddressRecord &&
            (coin.bitcoinAddressRecord as BitcoinAddressRecord).scriptHash == scriptHash);
        return null;
      }

      await Future.wait(unspent.map((unspent) async {
        final coin = BitcoinUnspent.fromJSON(addressRecord, unspent.toJson());
        coin.isChange = addressRecord.isChange;

        final tx = await getExistingTransaction(hash: coin.hash);

        if (tx != null) {
          coin.confirmations = tx.confirmations;
        }

        updatedUnspentCoins.add(coin);
      }));
    }));

    unspentCoins.addAll(updatedUnspentCoins);
    unspentCoins.forEach(updateCoin);

    await refreshUnspentCoinsInfo();
  }

  @action
  Future<void> addCoinInfo(BitcoinUnspent coin) async {
    // Check if the coin is already in the unspentCoinsInfo for the wallet
    final existingCoinInfo = unspentCoinsInfo.values
        .firstWhereOrNull((element) => element.walletId == walletInfo.id && element == coin);

    if (existingCoinInfo == null) {
      final newInfo = UnspentCoinsInfo(
        walletId: id,
        hash: coin.hash,
        isFrozen: coin.isFrozen,
        isSending: coin.isSending,
        noteRaw: coin.note,
        address: coin.bitcoinAddressRecord.address,
        value: coin.value,
        vout: coin.vout,
        isChange: coin.isChange,
      );

      await unspentCoinsInfo.add(newInfo);
    }
  }

  @action
  Future<void> refreshUnspentCoinsInfo() async {
    try {
      final List<dynamic> keys = [];
      final currentWalletUnspentCoins =
          unspentCoinsInfo.values.where((record) => record.walletId == id);

      for (final element in currentWalletUnspentCoins) {
        final existUnspentCoins = unspentCoins.where((coin) => element == coin);

        if (existUnspentCoins.isEmpty) {
          keys.add(element.key);
        }
      }

      if (keys.isNotEmpty) {
        await unspentCoinsInfo.deleteAll(keys);
      }
    } catch (e) {
      printV("refreshUnspentCoinsInfo $e");
    }
  }

  @action
  Future<void> onScripthashesStatusResponse(
    List<ElectrumWorkerScripthashesResponse> result,
  ) async {
    final noItemsWithStatus = result.length == 1 && result.first.status == null;
    if (noItemsWithStatus) {
      return;
    }

    final addresses = walletAddresses.allAddresses
        .where(
          (address) => result.any((e) => e.status != null && e.scripthash == address.scriptHash),
        )
        .toList();

    final scripthashesWithStatus =
        result.where((e) => e.status != null).map((e) => e.scripthash).toList();

    updateTransactions(addresses);
    updateBalance(scripthashesWithStatus);
    updateAllUnspents(scripthashesWithStatus);
  }

  @action
  Future<void> onHeadersResponse(ElectrumWorkerHeadersResponse response) async {
    currentChainTip = response.headerResponse.height;

    if (syncStatus is SyncedSyncStatus) {
      syncStatus = SyncedNewBlockSyncStatus(currentChainTip!);
    }

    if (response.anyTxWasUpdated) {
      transactionHistory.addMany(response.transactions);
      await save();
    }
  }

  @action
  Future<void> subscribeForHeaders([bool? wait]) async {
    if (_chainTipListenerOn) return;

    if (wait == true) {
      ElectrumWorkerHeadersSubscribeResponse.fromJson(
        await waitSendWorker(
          ElectrumWorkerHeadersSubscribeRequest(
            transactions: transactionHistory.transactions,
            walletType: type,
          ),
        ),
      );
    } else {
      sendWorker(
        ElectrumWorkerHeadersSubscribeRequest(
          transactions: transactionHistory.transactions,
          walletType: type,
        ),
      );
    }

    _chainTipListenerOn = true;
  }

  @action
  Future<void> onHistoriesResponse(ElectrumWorkerGetHistoryResponse response) async {
    final histories = response.result;
    final addressesWithHistory = <BitcoinAddressRecord>[];

    if (histories.isNotEmpty) {
      for (final addressHistory in histories) {
        final txs = addressHistory.txs;

        if (txs.isNotEmpty) {
          addressesWithHistory.add(addressHistory.addressRecord);

          for (final tx in txs) {
            transactionHistory.addOne(tx);
          }
        }
      }

      if (addressesWithHistory.isNotEmpty) {
        walletAddresses.addAddresses(addressesWithHistory);
      }
    }
  }

  Future<String?> canReplaceByFee(ElectrumTransactionInfo tx) async {
    if (tx.confirmations > 0) return null;

    try {
      final bundle = await getTransactionExpanded(hash: tx.txHash);
      tx.updateInputsAndOutputs(bundle, network);
      if (bundle.confirmations > 0) return null;
      return bundle.originalTransaction.canReplaceByFee ? bundle.originalTransaction.toHex() : null;
    } catch (e) {
      return null;
    }
  }

  Future<bool> isChangeSufficientForFee(String txId, int newFee) async {
    final bundle = await getTransactionExpanded(hash: txId);
    final outputs = bundle.originalTransaction.outputs;

    final ownAddresses = walletAddresses.allAddresses.map((addr) => addr.address).toSet();

    final receiverAmount = outputs
        .where(
          (output) => !ownAddresses.contains(
            BitcoinAddressUtils.addressFromOutputScript(output.scriptPubKey, network),
          ),
        )
        .fold<int>(0, (sum, output) => sum + output.amount.toInt());

    if (receiverAmount == 0) {
      throw Exception("Receiver output not found.");
    }

    final availableInputs = unspentCoins.where((utxo) => utxo.isSending && !utxo.isFrozen).toList();
    int totalBalance = availableInputs.fold<int>(
        0, (previousValue, element) => previousValue + element.value.toInt());

    int allInputsAmount = 0;
    for (int i = 0; i < bundle.originalTransaction.inputs.length; i++) {
      final input = bundle.originalTransaction.inputs[i];
      final inputTransaction = bundle.ins[i];
      final vout = input.txIndex;
      final outTransaction = inputTransaction.outputs[vout];
      allInputsAmount += outTransaction.amount.toInt();
    }

    int totalOutAmount = bundle.originalTransaction.outputs
        .fold<int>(0, (previousValue, element) => previousValue + element.amount.toInt());
    var currentFee = allInputsAmount - totalOutAmount;

    int remainingFee = (newFee - currentFee > 0) ? newFee - currentFee : newFee;
    return totalBalance - receiverAmount - remainingFee >= dustAmount;
  }

  Future<PendingBitcoinTransaction> replaceByFee(String hash, int newFee) async {
    try {
      final bundle = await getTransactionExpanded(hash: hash);

      final utxos = <UtxoWithAddress>[];
      final outputs = <BitcoinOutput>[];
      List<ECPrivate> privateKeys = [];

      var allInputsAmount = 0;
      String? memo;

      // Add original inputs
      for (var i = 0; i < bundle.originalTransaction.inputs.length; i++) {
        final input = bundle.originalTransaction.inputs[i];
        final inputTransaction = bundle.ins[i];
        final vout = input.txIndex;
        final outTransaction = inputTransaction.outputs[vout];
        final address =
            BitcoinAddressUtils.addressFromOutputScript(outTransaction.scriptPubKey, network);
        allInputsAmount += outTransaction.amount.toInt();

        final addressRecord =
            walletAddresses.allAddresses.firstWhere((element) => element.address == address);
        final btcAddress = RegexUtils.addressTypeFromStr(addressRecord.address, network);
        final path = addressRecord.derivationInfo.derivationPath
            .addElem(Bip32KeyIndex(
              BitcoinAddressUtils.getAccountFromChange(addressRecord.isChange),
            ))
            .addElem(Bip32KeyIndex(addressRecord.index));

        final privkey = ECPrivate.fromBip32(bip32: hdWallet.derive(path));

        privateKeys.add(privkey);

        utxos.add(
          UtxoWithAddress(
            utxo: BitcoinUtxo(
              txHash: input.txId,
              value: outTransaction.amount,
              vout: vout,
              scriptType: BitcoinAddressUtils.getScriptType(btcAddress),
            ),
            ownerDetails:
                UtxoAddressDetails(publicKey: privkey.getPublic().toHex(), address: btcAddress),
          ),
        );
      }

      // Add original outputs
      for (final out in bundle.originalTransaction.outputs) {
        final script = out.scriptPubKey.script;
        if (script.contains('OP_RETURN') && memo == null) {
          final index = script.indexOf('OP_RETURN');
          if (index + 1 <= script.length) {
            try {
              final opReturnData = script[index + 1].toString();
              memo = StringUtils.decode(BytesUtils.fromHexString(opReturnData));
              continue;
            } catch (_) {
              throw Exception('Cannot decode OP_RETURN data');
            }
          }
        }

        final address = BitcoinAddressUtils.addressFromOutputScript(out.scriptPubKey, network);
        final btcAddress = RegexUtils.addressTypeFromStr(address, network);
        outputs.add(BitcoinOutput(address: btcAddress, value: BigInt.from(out.amount.toInt())));
      }

      // Calculate the total amount and fees
      int totalOutAmount =
          outputs.fold<int>(0, (previousValue, output) => previousValue + output.value.toInt());
      int currentFee = allInputsAmount - totalOutAmount;
      int remainingFee = newFee - currentFee;

      if (remainingFee <= 0) {
        throw Exception("New fee must be higher than the current fee.");
      }

      // Deduct fee from change outputs first, if possible
      if (remainingFee > 0) {
        final changeAddresses = walletAddresses.allAddresses.where((element) => element.isHidden);
        for (int i = outputs.length - 1; i >= 0; i--) {
          final output = outputs[i];
          final isChange = changeAddresses
              .any((element) => element.address == output.address.toAddress(network));

          if (isChange) {
            int outputAmount = output.value.toInt();
            if (outputAmount > dustAmount) {
              int deduction = (outputAmount - dustAmount >= remainingFee)
                  ? remainingFee
                  : outputAmount - dustAmount;
              outputs[i] = BitcoinOutput(
                  address: output.address, value: BigInt.from(outputAmount - deduction));
              remainingFee -= deduction;

              if (remainingFee <= 0) break;
            }
          }
        }
      }

      // If still not enough, add UTXOs until the fee is covered
      if (remainingFee > 0) {
        final unusedUtxos = unspentCoins
            .where((utxo) => utxo.isSending && !utxo.isFrozen && utxo.confirmations! > 0)
            .toList();

        for (final utxo in unusedUtxos) {
          final address = RegexUtils.addressTypeFromStr(utxo.address, network);
          final privkey = ECPrivate.fromBip32(bip32: hdWallet);
          privateKeys.add(privkey);

          utxos.add(
            UtxoWithAddress(
              utxo: BitcoinUtxo(
                  txHash: utxo.hash,
                  value: BigInt.from(utxo.value),
                  vout: utxo.vout,
                  scriptType: BitcoinAddressUtils.getScriptType(address)),
              ownerDetails:
                  UtxoAddressDetails(publicKey: privkey.getPublic().toHex(), address: address),
            ),
          );

          allInputsAmount += utxo.value;
          remainingFee -= utxo.value;

          if (remainingFee < 0) {
            final changeOutput = outputs.firstWhereOrNull((output) => walletAddresses.allAddresses
                .any((addr) => addr.address == output.address.toAddress(network)));
            if (changeOutput != null) {
              final newValue = changeOutput.value.toInt() + (-remainingFee);
              outputs[outputs.indexOf(changeOutput)] =
                  BitcoinOutput(address: changeOutput.address, value: BigInt.from(newValue));
            } else {
              final changeAddress = await walletAddresses.getChangeAddress();
              outputs.add(BitcoinOutput(
                  address: RegexUtils.addressTypeFromStr(changeAddress.address, network),
                  value: BigInt.from(-remainingFee)));
            }

            remainingFee = 0;
            break;
          }

          if (remainingFee <= 0) break;
        }
      }

      // Deduct from the receiver's output if remaining fee is still greater than 0
      if (remainingFee > 0) {
        for (int i = 0; i < outputs.length; i++) {
          final output = outputs[i];
          int outputAmount = output.value.toInt();

          if (outputAmount > dustAmount) {
            int deduction = (outputAmount - dustAmount >= remainingFee)
                ? remainingFee
                : outputAmount - dustAmount;

            outputs[i] = BitcoinOutput(
                address: output.address, value: BigInt.from(outputAmount - deduction));
            remainingFee -= deduction;

            if (remainingFee <= 0) break;
          }
        }
      }

      // Final check if the remaining fee couldn't be deducted
      if (remainingFee > 0) {
        throw Exception("Not enough funds to cover the fee.");
      }

      // Identify all change outputs
      final changeAddresses = walletAddresses.allAddresses.where((element) => element.isChange);
      final List<BitcoinOutput> changeOutputs = outputs
          .where((output) =>
              changeAddresses.any((addr) => addr.address == output.address.toAddress(network)))
          .toList();

      int totalChangeAmount =
          changeOutputs.fold<int>(0, (sum, output) => sum + output.value.toInt());

      // The final amount that the receiver will receive
      int sendingAmount = allInputsAmount - newFee - totalChangeAmount;

      final txb = BitcoinTransactionBuilder(
        utxos: utxos,
        outputs: outputs,
        fee: BigInt.from(newFee),
        network: network,
        memo: memo,
        outputOrdering: BitcoinOrdering.none,
        enableRBF: true,
      );

      final transaction = txb.buildTransaction((txDigest, utxo, publicKey, sighash) {
        final key =
            privateKeys.firstWhereOrNull((element) => element.getPublic().toHex() == publicKey);
        if (key == null) {
          throw Exception("Cannot find private key");
        }

        if (utxo.utxo.isP2tr) {
          return key.signTapRoot(txDigest, sighash: sighash);
        } else {
          return key.signInput(txDigest, sigHash: sighash);
        }
      });

      return PendingBitcoinTransaction(
        transaction,
        type,
        waitSendWorker: waitSendWorker,
        amount: sendingAmount,
        fee: newFee,
        hasChange: changeOutputs.isNotEmpty,
        feeRate: newFee.toString(),
      )..addListener((transaction) async {
          transactionHistory.transactions.values.forEach((tx) {
            if (tx.id == hash) {
              tx.isReplaced = true;
              tx.isPending = false;
              transactionHistory.addOne(tx);
            }
          });
          transactionHistory.addOne(transaction);
          await updateBalance();
          await updateAllUnspents();
        });
    } catch (e) {
      throw e;
    }
  }

  Future<String> getTransactionHex({required String hash}) async {
    return ElectrumWorkerTxHexResponse.fromJson(
      await waitSendWorker(
        ElectrumWorkerTxHexRequest(txHash: hash, currentChainTip: currentChainTip!),
      ),
    ).result;
  }

  Future<ElectrumTransactionBundle> getTransactionExpanded({required String hash}) async {
    return ElectrumWorkerTxExpandedResponse.fromJson(
      await waitSendWorker(
        ElectrumWorkerTxExpandedRequest(txHash: hash, currentChainTip: currentChainTip!),
      ),
    ).result;
  }

  Future<ElectrumTransactionInfo?> getExistingTransaction({required String hash}) async {
    var tx = transactionHistory.transactions.values.firstWhereOrNull((tx) => tx.txHash == hash);
    tx ??= await fetchTransactionInfo(hash: hash);
    return tx;
  }

  Future<ElectrumTransactionInfo?> fetchTransactionInfo({required String hash, int? height}) async {
    try {
      return ElectrumTransactionInfo.fromElectrumBundle(
        await getTransactionExpanded(hash: hash),
        walletInfo.type,
        network,
        addresses: walletAddresses.allAddresses.map((e) => e.address).toSet(),
        height: height,
      );
    } catch (_) {
      return null;
    }
  }

  @override
  @action
  Future<Map<String, ElectrumTransactionInfo>> fetchTransactions() async {
    throw UnimplementedError();
  }

  Future<ElectrumWorkerGetHistoryRequest> getUpdateTransactionsRequest([
    List<BitcoinAddressRecord>? addresses,
  ]) async {
    return ElectrumWorkerGetHistoryRequest(
      addresses: addresses ?? walletAddresses.allAddresses.toList(),
      storedTxs: transactionHistory.transactions.values.toList(),
      walletType: type,
      // If we still don't have currentChainTip, txs will still be fetched but shown
      // with confirmations as 0 but will be auto fixed on onHeadersResponse
      chainTip: currentChainTip ?? -1,
      network: network,
    );
  }

  Future<ElectrumWorkerGetHistoryResponse?> updateTransactions([
    List<BitcoinAddressRecord>? addresses,
    bool? wait,
  ]) async {
    if (wait == true) {
      return ElectrumWorkerGetHistoryResponse.fromJson(
        await waitSendWorker(
          await getUpdateTransactionsRequest(addresses),
        ),
      );
    } else {
      return sendWorker(
        await getUpdateTransactionsRequest(addresses),
      );
    }
  }

  @action
  Future<List<ElectrumWorkerScripthashesResponse>?> subscribeForStatuses([
    List<BitcoinAddressRecord>? addresses,
    bool? wait,
  ]) async {
    Map<String, String> scripthashByAddress = {};
    Map<String, String> addressByScripthashes = {};
    (addresses ?? walletAddresses.allAddresses).forEach((addressRecord) {
      scripthashByAddress[addressRecord.address] = addressRecord.scriptHash;
      addressByScripthashes[addressRecord.scriptHash] = addressRecord.address;
    });

    if (scripthashByAddress.isEmpty || addressByScripthashes.isEmpty) {
      return null;
    }

    if (wait == true)
      return ElectrumWorkerScripthashesSubscribeResponse.fromJson(
        await waitSendWorker(
          ElectrumWorkerScripthashesSubscribeRequest(
            scripthashByAddress: scripthashByAddress,
            addressByScripthashes: addressByScripthashes,
          ),
        ),
      ).result;
    else
      sendWorker(
        ElectrumWorkerScripthashesSubscribeRequest(
          scripthashByAddress: scripthashByAddress,
          addressByScripthashes: addressByScripthashes,
        ),
      );

    return null;
  }

  @action
  void onBalanceResponse(ElectrumGetBalanceResponse balanceResults) {
    var totalFrozen = 0;
    var totalConfirmed = 0;
    var totalUnconfirmed = 0;

    if (unspentCoins.isNotEmpty)
      unspentCoins.forInfo(unspentCoinsInfo.values).forEach((unspentCoinInfo) {
        if (unspentCoinInfo.isFrozen) {
          totalFrozen += unspentCoinInfo.value;
        }
      });

    for (int i = 0; i < balanceResults.balances.length; i++) {
      final scripthash = balanceResults.scripthashes[i];
      final addressRecord = walletAddresses.allAddresses.firstWhereOrNull(
        (element) => element.scriptHash == scripthash,
      );

      if (addressRecord != null) {
        final balance = balanceResults.balances[i];
        addressRecord.balance = balance;
      }
    }

    for (final addressRecord in [
      ...walletAddresses.allAddresses,
      ...walletAddresses.otherAddresses
    ]) {
      final balance = addressRecord.balance;

      if (balance.hasBalance()) {
        totalConfirmed += balance.confirmed;
        totalUnconfirmed += balance.unconfirmed;
      }
    }

    balance[currency] = ElectrumBalance(
      confirmed: totalConfirmed,
      unconfirmed: totalUnconfirmed,
      frozen: totalFrozen,
    );
  }

  @action
  Future<ElectrumWorkerGetBalanceResponse?> updateBalance([
    List<String>? scripthashes,
    bool? wait,
  ]) async {
    scripthashes ??= walletAddresses.allScriptHashes;

    if (scripthashes.isEmpty) {
      return null;
    }

    if (wait == true) {
      return ElectrumWorkerGetBalanceResponse.fromJson(
        await waitSendWorker(
          ElectrumWorkerGetBalanceRequest(scripthashes: scripthashes),
        ),
      );
    } else {
      return sendWorker(
        ElectrumWorkerGetBalanceRequest(scripthashes: scripthashes),
      );
    }
  }

  @override
  void setExceptionHandler(void Function(FlutterErrorDetails) onError) => _onError = onError;

  Future<String> signMessage(String message, {String? address = null}) async {
    final record = walletAddresses.getFromAddresses(address!);

    final path = Bip32PathParser.parse(walletInfo.derivationInfo!.derivationPath!)
        .addElem(
          Bip32KeyIndex(BitcoinAddressUtils.getAccountFromChange(record.isChange)),
        )
        .addElem(Bip32KeyIndex(record.index));

    final priv = ECPrivate.fromHex(hdWallet.derive(path).privateKey.toHex());

    final hexEncoded =
        priv.signMessage(StringUtils.encode(message), messagePrefix: SIGN_MESSAGE_PREFIX);
    final decodedSig = hex.decode(hexEncoded);
    return base64Encode(decodedSig);
  }

  @override
  Future<bool> verifyMessage(String message, String signature, {String? address = null}) async {
    if (address == null) {
      return false;
    }

    List<int> sigDecodedBytes = [];

    if (signature.endsWith('=')) {
      sigDecodedBytes = base64.decode(signature);
    } else {
      sigDecodedBytes = BytesUtils.fromHexString(signature);
    }

    if (sigDecodedBytes.length != 64 && sigDecodedBytes.length != 65) {
      throw ArgumentException(
          "signature must be 64 bytes without recover-id or 65 bytes with recover-id");
    }

    final messageHash = QuickCrypto.sha256Hash(
      BitcoinSignerUtils.magicMessage(StringUtils.encode(message), SIGN_MESSAGE_PREFIX),
    );

    List<int> correctSignature =
        sigDecodedBytes.length == 65 ? sigDecodedBytes.sublist(1) : List.from(sigDecodedBytes);
    List<int> rBytes = correctSignature.sublist(0, 32);
    List<int> sBytes = correctSignature.sublist(32);
    final sig = ECDSASignature(BigintUtils.fromBytes(rBytes), BigintUtils.fromBytes(sBytes));

    List<int> possibleRecoverIds = [0, 1];

    final baseAddress = RegexUtils.addressTypeFromStr(address, network);

    for (int recoveryId in possibleRecoverIds) {
      final pubKey = sig.recoverPublicKey(messageHash, Curves.generatorSecp256k1, recoveryId);

      final recoveredPub = ECPublic.fromBytes(pubKey!.toBytes());

      String? recoveredAddress;

      if (baseAddress is P2pkAddress) {
        recoveredAddress = recoveredPub.toP2pkAddress().toAddress(network);
      } else if (baseAddress is P2pkhAddress) {
        recoveredAddress = recoveredPub.toP2pkhAddress().toAddress(network);
      } else if (baseAddress is P2wshAddress) {
        recoveredAddress = recoveredPub.toP2wshAddress().toAddress(network);
      } else if (baseAddress is P2wpkhAddress) {
        recoveredAddress = recoveredPub.toP2wpkhAddress().toAddress(network);
      }

      if (recoveredAddress == address) {
        return true;
      }
    }

    return false;
  }

  @action
  void _onConnectionStatusChange(ConnectionStatus status) {
    switch (status) {
      case ConnectionStatus.connected:
        if (syncStatus is NotConnectedSyncStatus ||
            syncStatus is LostConnectionSyncStatus ||
            syncStatus is ConnectingSyncStatus) {
          syncStatus = ConnectedSyncStatus();
        }

        break;
      case ConnectionStatus.disconnected:
        if (syncStatus is! NotConnectedSyncStatus &&
            syncStatus is! ConnectingSyncStatus &&
            syncStatus is! SynchronizingSyncStatus) {
          syncStatus = NotConnectedSyncStatus();
        }
        break;
      case ConnectionStatus.failed:
        if (syncStatus is! LostConnectionSyncStatus) {
          syncStatus = LostConnectionSyncStatus();
        }
        break;
      case ConnectionStatus.connecting:
        if (syncStatus is! ConnectingSyncStatus) {
          syncStatus = ConnectingSyncStatus();
        }
        break;
      default:
    }
  }

  @action
  void syncStatusReaction(SyncStatus syncStatus) {
    final isDisconnectedStatus =
        syncStatus is NotConnectedSyncStatus || syncStatus is LostConnectionSyncStatus;

    if (syncStatus is ConnectingSyncStatus || isDisconnectedStatus) {
      // Needs to re-subscribe to all scripthashes when reconnected
      _chainTipListenerOn = false;
    }

    if (isDisconnectedStatus) {
      if (_isTryingToConnect) return;

      _isTryingToConnect = true;

      Timer(Duration(seconds: 5), () {
        if (this.syncStatus is NotConnectedSyncStatus ||
            this.syncStatus is LostConnectionSyncStatus) {
          if (node == null) return;

          connectToNode(node: this.node!);
        }
        _isTryingToConnect = false;
      });
    }

    if (syncStatus is SyncedNewBlockSyncStatus) {
      // Message is shown on the UI for 3 seconds, then reverted to synced
      Timer(Duration(seconds: 3), () {
        if (this.syncStatus is SyncedNewBlockSyncStatus) this.syncStatus = SyncedSyncStatus();
      });
    }

    if (syncStatus is SyncedNewPaymentSyncStatus) {
      syncStatusLock = true;

      // Message is shown on the UI for 3 seconds, then reverted to synced
      Timer(Duration(seconds: 2), () {
        if (this.syncStatus is SyncedNewPaymentSyncStatus) {
          this.syncStatusLock = false;
        }
      });
    }
  }

  @action
  Future<void> _onAddressesDiscovered(List<BitcoinAddressRecord> addresses) async {
    final scripthashByAddress = await subscribeForStatuses(addresses, true);
    final noItemsWithStatus =
        scripthashByAddress!.length == 1 && scripthashByAddress.first.status == null;

    final firstAddress = addresses.first;

    // NOTE: Did not find any status for old/wrong derivation addresses, discard them
    // (don't add to addresses list)
    if (firstAddress.seedBytesType!.isOldDerivation && noItemsWithStatus) {
      walletAddresses.discoveredAddressesRecord.addDiscovered(
        addressType: firstAddress.type,
        seedBytesType: firstAddress.seedBytesType!,
        derivationPath: firstAddress.derivationInfo.derivationPath.toString(),
        isChange: firstAddress.isChange,
        discovered: true,
      );
      initAddresses();
      return;
    }

    walletAddresses.addAddresses(addresses);
    walletAddresses.discoveredAddressesRecord.addDiscovered(
      addressType: firstAddress.type,
      seedBytesType: firstAddress.seedBytesType!,
      derivationPath: firstAddress.derivationInfo.derivationPath.toString(),
      isChange: firstAddress.isChange,
      discovered: true,
    );

    // NOTE: Has items with status under gap limit, continue discovering
    if (!noItemsWithStatus)
      discoverNewAddresses(
        seedBytesType: firstAddress.seedBytesType!,
        isChange: firstAddress.isChange,
        addressType: firstAddress.type,
        derivationInfo: firstAddress.derivationInfo,
        scripthashStatuses: scripthashByAddress,
      );
    // NOTE: Otherwise, sync all the discovered addresses so far
    else {
      subscribeForStatuses(
        walletAddresses.addressesRecords
            .getRecords(
              seedBytesType: firstAddress.seedBytesType!,
              addressType: firstAddress.type,
              derivationPath: firstAddress.derivationInfo.derivationPath.toString(),
              isChange: firstAddress.isChange,
            )
            .whereType<BitcoinAddressRecord>()
            .toList(),
      );
      initAddresses();
    }
  }

  @action
  Future<bool> generateInitialAddresses({
    required BitcoinAddressType addressType,
    required SeedBytesType seedBytesType,
    BitcoinDerivationInfo? bitcoinDerivationInfo,
  }) async {
    bool discovered = false;

    bitcoinDerivationInfo ??= BitcoinAddressUtils.getDerivationFromType(
      addressType,
      network: network,
      isElectrum: seedBytesType.isElectrum,
    );

    for (final isChange in [true, false]) {
      final existingAddresses = walletAddresses.addressesRecords.getRecords(
        addressType: addressType,
        seedBytesType: seedBytesType,
        derivationPath: bitcoinDerivationInfo.derivationPath.toString(),
        isChange: isChange,
      );
      final discoveredExistingAddresses = walletAddresses.discoveredAddressesRecord.getIsDiscovered(
        addressType: addressType,
        seedBytesType: seedBytesType,
        derivationPath: bitcoinDerivationInfo.derivationPath.toString(),
        isChange: isChange,
      );

      final gapCount = isChange
          ? ElectrumWalletAddressesBase.INITIAL_CHANGE_COUNT
          : ElectrumWalletAddressesBase.INITIAL_RECEIVE_COUNT;

      if (!discoveredExistingAddresses && existingAddresses.length < gapCount) {
        discoverNewAddresses(
          addressType: addressType,
          seedBytesType: seedBytesType,
          derivationInfo: bitcoinDerivationInfo,
          isChange: isChange,
          startIndex: existingAddresses.length,
        );
        discovered = true;
      }

      walletAddresses.discoveredAddressesRecord.addDiscovered(
        addressType: addressType,
        seedBytesType: seedBytesType,
        derivationPath: bitcoinDerivationInfo.derivationPath.toString(),
        isChange: isChange,
        discovered: true,
      );
    }

    return discovered;
  }

  void discoverNewAddresses({
    required SeedBytesType seedBytesType,
    required bool isChange,
    required BitcoinAddressType addressType,
    required BitcoinDerivationInfo derivationInfo,
    int? startIndex,
    List<ElectrumWorkerScripthashesResponse>? scripthashStatuses,
  }) async {
    final countToDiscover = isChange
        ? ElectrumWalletAddressesBase.INITIAL_CHANGE_COUNT
        : ElectrumWalletAddressesBase.INITIAL_RECEIVE_COUNT;

    final recordList = walletAddresses.addressesRecords.getRecords(
      seedBytesType: seedBytesType,
      addressType: addressType,
      derivationPath: derivationInfo.derivationPath.toString(),
      isChange: isChange,
    );

    startIndex ??= recordList.length;

    late bool needsToDiscover;

    if (recordList.length < countToDiscover) {
      needsToDiscover = true;
    } else if (recordList.length == countToDiscover) {
      needsToDiscover = recordList.any((record) => !record.getIsUsed());
    } else {
      needsToDiscover = recordList.sublist(recordList.length - countToDiscover).any(
        (record) {
          return scripthashStatuses?.any(
                (scripthashStatus) => scripthashStatus.scripthash == record.scriptHash,
              ) ??
              record.getIsUsed();
        },
      );
    }

    if (!needsToDiscover) {
      return;
    }

    workerSendPort!.send(
      ElectrumWorkerDiscoverAddressesRequest(
        id: _messageId,
        count: countToDiscover,
        walletType: type,
        startIndex: startIndex,
        seedBytesType: seedBytesType,
        derivationInfo: derivationInfo,
        isChange: isChange,
        addressType: addressType,
        xpriv: hdWallets[seedBytesType]!.privateKey.toExtended,
        network: network,
      ).toJson(),
    );
  }

  @override
  String formatCryptoAmount(String amount) {
    final amountInt = int.parse(amount);
    return BitcoinAmountUtils.bitcoinAmountToString(amount: amountInt);
  }
}

class ElectrumEstimatedTx {
  ElectrumEstimatedTx({
    required this.utxos,
    required this.inputPrivKeyInfos,
    required this.publicKeys,
    required this.fee,
    required this.amount,
    required this.hasChange,
    required this.isSendAll,
    this.memo,
    required this.spendsUnconfirmedTX,
  });

  final List<UtxoWithAddress> utxos;
  final List<ECPrivateInfo> inputPrivKeyInfos;
  final Map<String, PublicKeyWithDerivationPath> publicKeys; // PubKey to derivationPath
  final int fee;
  final int amount;

  final bool hasChange;
  final bool isSendAll;
  final String? memo;
  final bool spendsUnconfirmedTX;
}

class PublicKeyWithDerivationPath {
  const PublicKeyWithDerivationPath(this.publicKey, this.derivationPath);

  final String derivationPath;
  final String publicKey;
}

class ElectrumTxCreateUtxoDetails {
  final List<BitcoinUnspent> availableInputs;
  final List<BitcoinUnspent> unconfirmedCoins;
  final List<UtxoWithAddress> utxos;
  final List<Outpoint> vinOutpoints;
  final List<ECPrivateInfo> inputPrivKeyInfos;
  final Map<String, PublicKeyWithDerivationPath> publicKeys; // PubKey to derivationPath
  final int allInputsAmount;
  final bool spendsUnconfirmedTX;

  ElectrumTxCreateUtxoDetails({
    required this.availableInputs,
    required this.unconfirmedCoins,
    required this.utxos,
    required this.vinOutpoints,
    required this.inputPrivKeyInfos,
    required this.publicKeys,
    required this.allInputsAmount,
    required this.spendsUnconfirmedTX,
  });
}

class ElectrumUnspentCoins extends ObservableSet<BitcoinUnspent> {
  ElectrumUnspentCoins() : super();

  static ElectrumUnspentCoins of(Iterable<BitcoinUnspent> unspentCoins) {
    final coins = ElectrumUnspentCoins();
    coins.addAll(unspentCoins);
    return coins;
  }

  List<UnspentCoinsInfo> forInfo(Iterable<UnspentCoinsInfo> unspentCoinsInfo) {
    return unspentCoinsInfo.where((element) {
      final info = this.firstWhereOrNull(
        (info) =>
            element.hash == info.hash &&
            element.vout == info.vout &&
            element.address == info.bitcoinAddressRecord.address &&
            element.value == info.value,
      );

      return info != null;
    }).toList();
  }

  List<BitcoinUnspent> fromInfo(Iterable<UnspentCoinsInfo> unspentCoinsInfo) {
    return this.where((element) {
      final info = unspentCoinsInfo.firstWhereOrNull(
        (info) =>
            element.hash == info.hash &&
            element.vout == info.vout &&
            element.bitcoinAddressRecord.address == info.address &&
            element.value == info.value,
      );

      return info != null;
    }).toList();
  }
}

class CreateTxData {
  final int amount;
  final int feeRate;
  final List<BitcoinOutput> outputs;
  final bool sendAll;
  final String? memo;

  CreateTxData({
    required this.amount,
    required this.feeRate,
    required this.outputs,
    required this.sendAll,
    required this.memo,
  });
}

class InitAddressesData {
  bool? isDiscovered;
  bool? discovered;

  InitAddressesData({
    required this.isDiscovered,
    required this.discovered,
  });
}