stack_wallet/lib/wallets/wallet/wallet_mixin_interfaces/spark_interface.dart

import 'dart:convert';
import 'dart:typed_data';

import 'package:flutter_libsparkmobile/flutter_libsparkmobile.dart';
import 'package:isar/isar.dart';
import 'package:stackwallet/models/isar/models/blockchain_data/address.dart';
import 'package:stackwallet/utilities/amount/amount.dart';
import 'package:stackwallet/utilities/extensions/extensions.dart';
import 'package:stackwallet/wallets/crypto_currency/crypto_currency.dart';
import 'package:stackwallet/wallets/isar/models/spark_coin.dart';
import 'package:stackwallet/wallets/models/tx_data.dart';
import 'package:stackwallet/wallets/wallet/intermediate/bip39_hd_wallet.dart';
import 'package:stackwallet/wallets/wallet/wallet_mixin_interfaces/electrumx_interface.dart';

mixin SparkInterface on Bip39HDWallet, ElectrumXInterface {
  @override
  Future<void> init() async {
    Address? address = await getCurrentReceivingSparkAddress();
    if (address == null) {
      address = await generateNextSparkAddress();
      await mainDB.putAddress(address);
    } // TODO add other address types to wallet info?

    // await info.updateReceivingAddress(
    //   newAddress: address.value,
    //   isar: mainDB.isar,
    // );

    await super.init();
  }

  @override
  Future<List<Address>> fetchAddressesForElectrumXScan() async {
    final allAddresses = await mainDB
        .getAddresses(walletId)
        .filter()
        .not()
        .group(
          (q) => q
              .typeEqualTo(AddressType.spark)
              .or()
              .typeEqualTo(AddressType.nonWallet)
              .or()
              .subTypeEqualTo(AddressSubType.nonWallet),
        )
        .findAll();
    return allAddresses;
  }

  Future<Address?> getCurrentReceivingSparkAddress() async {
    return await mainDB.isar.addresses
        .where()
        .walletIdEqualTo(walletId)
        .filter()
        .typeEqualTo(AddressType.spark)
        .sortByDerivationIndexDesc()
        .findFirst();
  }

  Future<Uint8List> _getSpendKey() async {
    final mnemonic = await getMnemonic();
    final mnemonicPassphrase = await getMnemonicPassphrase();

    // TODO call ffi lib to generate spend key

    throw UnimplementedError();
  }

  Future<Address> generateNextSparkAddress() async {
    final highestStoredDiversifier =
        (await getCurrentReceivingSparkAddress())?.derivationIndex;

    // default to starting at 1 if none found
    final int diversifier = (highestStoredDiversifier ?? 0) + 1;

    // TODO: check that this stays constant and only the diversifier changes?
    const index = 1;

    final root = await getRootHDNode();
    final String derivationPath;
    if (cryptoCurrency.network == CryptoCurrencyNetwork.test) {
      derivationPath = "$kSparkBaseDerivationPathTestnet$index";
    } else {
      derivationPath = "$kSparkBaseDerivationPath$index";
    }
    final keys = root.derivePath(derivationPath);

    final String addressString = await LibSpark.getAddress(
      privateKey: keys.privateKey.data,
      index: index,
      diversifier: diversifier,
      isTestNet: cryptoCurrency.network == CryptoCurrencyNetwork.test,
    );

    return Address(
      walletId: walletId,
      value: addressString,
      publicKey: keys.publicKey.data,
      derivationIndex: diversifier,
      derivationPath: DerivationPath()..value = derivationPath,
      type: AddressType.spark,
      subType: AddressSubType.receiving,
    );
  }

  Future<Amount> estimateFeeForSpark(Amount amount) async {
    throw UnimplementedError();
  }

  /// Spark to Spark/Transparent (spend) creation
  Future<TxData> prepareSendSpark({
    required TxData txData,
  }) async {
    // https://docs.google.com/document/d/1RG52GoYTZDvKlZz_3G4sQu-PpT6JWSZGHLNswWcrE3o/edit
    // To generate  a spark spend we need to call createSparkSpendTransaction,
    // first unlock the wallet and generate all 3 spark keys,
    final spendKey = await _getSpendKey();

    //
    // recipients is a list of pairs of amounts and bools, this is for transparent
    // outputs, first how much to send and second, subtractFeeFromAmount argument
    // for each receiver.
    //
    // privateRecipients is again the list of pairs, first the receiver data
    // which has following members, Address which is any spark address,
    // amount (v) how much we want to send, and memo which can be any string
    // with 32 length (any string we want to send to receiver), and the second
    // subtractFeeFromAmount,
    //
    // coins is the list of all our available spark coins
    //
    // cover_set_data_all is the list of all anonymity sets,
    //
    // idAndBlockHashes_all is the list of block hashes for each anonymity set
    //
    // txHashSig is the transaction hash only without spark data, tx version,
    // type, transparent outputs and everything else should be set before generating it.
    //
    // fee is a output data
    //
    // serializedSpend is a output data, byte array with spark spend, we need
    // to put it into vExtraPayload (this naming can be different in your codebase)
    //
    // outputScripts is a output data, it is a list of scripts, which we need
    // to put in separate tx outputs, and keep the order,

    throw UnimplementedError();
  }

  // this may not be needed for either mints or spends or both
  Future<TxData> confirmSendSpark({
    required TxData txData,
  }) async {
    throw UnimplementedError();
  }

  // TODO lots of room for performance improvements here. Should be similar to
  // recoverSparkWallet but only fetch and check anonymity set data that we
  // have not yet parsed.
  Future<void> refreshSparkData() async {
    final sparkAddresses = await mainDB.isar.addresses
        .where()
        .walletIdEqualTo(walletId)
        .filter()
        .typeEqualTo(AddressType.spark)
        .findAll();

    final Set<String> paths =
        sparkAddresses.map((e) => e.derivationPath!.value).toSet();

    try {
      const index = 1;

      final root = await getRootHDNode();

      final latestSparkCoinId = await electrumXClient.getSparkLatestCoinId();

      // TODO improve performance by adding these calls to the cached client
      final futureResults = await Future.wait([
        electrumXClient.getSparkAnonymitySet(
          coinGroupId: latestSparkCoinId.toString(),
        ),
        electrumXClient.getSparkUsedCoinsTags(
          startNumber: 0,
        ),
      ]);

      final anonymitySet = futureResults[0];
      final spentCoinTags = List<String>.from(
        futureResults[1]["tags"] as List,
      ).toSet();

      // find our coins
      final List<SparkCoin> myCoins = [];

      for (final path in paths) {
        final keys = root.derivePath(path);

        final privateKeyHex = keys.privateKey.data.toHex;

        for (final dynData in anonymitySet["coins"] as List) {
          final data = List<String>.from(dynData as List);

          if (data.length != 2) {
            throw Exception("Unexpected serialized coin info found");
          }

          final serializedCoin = data.first;
          final txHash = base64ToReverseHex(data.last);

          final coin = LibSpark.identifyAndRecoverCoin(
            serializedCoin,
            privateKeyHex: privateKeyHex,
            index: index,
            isTestNet: cryptoCurrency.network == CryptoCurrencyNetwork.test,
          );

          // its ours
          if (coin != null) {
            final SparkCoinType coinType;
            switch (coin.type.value) {
              case 0:
                coinType = SparkCoinType.mint;
              case 1:
                coinType = SparkCoinType.spend;
              default:
                throw Exception("Unknown spark coin type detected");
            }
            myCoins.add(
              SparkCoin(
                walletId: walletId,
                type: coinType,
                isUsed: spentCoinTags.contains(coin.lTagHash!),
                address: coin.address!,
                txHash: txHash,
                valueIntString: coin.value!.toString(),
                lTagHash: coin.lTagHash!,
                tag: coin.tag,
                memo: coin.memo,
                serial: coin.serial,
                serialContext: coin.serialContext,
                diversifierIntString: coin.diversifier!.toString(),
                encryptedDiversifier: coin.encryptedDiversifier,
              ),
            );
          }
        }
      }

      // update wallet spark coins in isar
      if (myCoins.isNotEmpty) {
        await mainDB.isar.writeTxn(() async {
          await mainDB.isar.sparkCoins.putAll(myCoins);
        });
      }

      // refresh spark balance?

      throw UnimplementedError();
    } catch (e, s) {
      // todo logging

      rethrow;
    }
  }

  /// Should only be called within the standard wallet [recover] function due to
  /// mutex locking. Otherwise behaviour MAY be undefined.
  Future<void> recoverSparkWallet(
      // {
      // required int latestSetId,
      // required Map<dynamic, dynamic> setDataMap,
      // required Set<String> usedSerialNumbers,
      // }
      ) async {
    try {
      // do we need to generate any spark address(es) here?

      final latestSparkCoinId = await electrumXClient.getSparkLatestCoinId();

      // TODO improve performance by adding this call to the cached client
      final anonymitySet = await electrumXClient.getSparkAnonymitySet(
        coinGroupId: latestSparkCoinId.toString(),
      );

      // TODO loop over set and see which coins are ours using the FFI call `identifyCoin`
      List myCoins = [];

      // fetch metadata for myCoins

      // create list of Spark Coin isar objects

      // update wallet spark coins in isar

      throw UnimplementedError();
    } catch (e, s) {
      // todo logging

      rethrow;
    }
  }

  /// Transparent to Spark (mint) transaction creation.
  Future<TxData> prepareSparkMintTransaction({required TxData txData}) async {
    // https://docs.google.com/document/d/1RG52GoYTZDvKlZz_3G4sQu-PpT6JWSZGHLNswWcrE3o/edit

    // this kind of transaction is generated like a regular transaction, but in
    // place of regular outputs we put spark outputs, so for that we call
    // createSparkMintRecipients function, we get spark related data,
    // everything else we do like for regular transaction, and we put CRecipient
    // object as a tx outputs, we need to keep the order..
    // First we pass spark::MintedCoinData>, has following members, Address
    // which is any spark address, amount (v) how much we want to send, and
    // memo which can be any string with 32 length (any string we want to send
    // to receiver), serial_context is a byte array, which should be unique for
    // each transaction, and for that we serialize and put all inputs into
    // serial_context vector. So we construct the input part of the transaction
    // first then we generate spark related data. And we sign like regular
    // transactions at the end.

    // Validate inputs.

    // There should be at least one recipient.
    if (txData.recipients == null || txData.recipients!.isEmpty) {
      throw Exception("No recipients provided");
    }

    // For now let's limit to one recipient.
    if (txData.recipients!.length > 1) {
      throw Exception("Only one recipient supported");
    }

    // Limit outputs per tx to 16.
    //
    // See SPARK_OUT_LIMIT_PER_TX at https://github.com/firoorg/sparkmobile/blob/ef2e39aae18ecc49e0ddc63a3183e9764b96012e/include/spark.h#L16
    // TODO limit outputs to 16.

    // Limit spend value per tx to 1000000000000 satoshis.
    //
    // See SPARK_VALUE_SPEND_LIMIT_PER_TRANSACTION at https://github.com/firoorg/sparkmobile/blob/ef2e39aae18ecc49e0ddc63a3183e9764b96012e/include/spark.h#L17
    // and COIN https://github.com/firoorg/sparkmobile/blob/ef2e39aae18ecc49e0ddc63a3183e9764b96012e/bitcoin/amount.h#L17
    // Note that as MAX_MONEY is greater than this limit, we can ignore it.  See https://github.com/firoorg/sparkmobile/blob/ef2e39aae18ecc49e0ddc63a3183e9764b96012e/bitcoin/amount.h#L31
    // TODO limit spend value per tx to 1000000000000 satoshis.

    // Create the serial context.
    List<int> serialContext = [];
    // TODO set serialContext to the serialized inputs.

    // Create outputs.
    final mintRecipients = LibSpark.createSparkMintRecipients(
      outputs: txData.recipients!
          .map((e) => (
                sparkAddress: e.address,
                value: e.amount.raw.toInt(),
                memo: "Stackwallet spark mint"
              ))
          .toList(),
      serialContext: Uint8List.fromList(serialContext),
    );

    // TODO Add outputs to txData.

    throw UnimplementedError();
  }

  /// Broadcast a tx and TODO update Spark balance.
  Future<TxData> confirmSparkMintTransaction({required TxData txData}) async {
    // Broadcast tx.
    final txid = await electrumXClient.broadcastTransaction(
      rawTx: txData.raw!,
    );

    // Check txid.
    assert(txid == txData.txid!);

    // TODO update spark balance.

    return txData.copyWith(
      txid: txid,
    );
  }

  @override
  Future<void> updateBalance() async {
    // call to super to update transparent balance (and lelantus balance if
    // what ever class this mixin is used on uses LelantusInterface as well)
    final normalBalanceFuture = super.updateBalance();

    // todo: spark balance aka update info.tertiaryBalance

    // wait for normalBalanceFuture to complete before returning
    await normalBalanceFuture;
  }
}

String base64ToReverseHex(String source) =>
    base64Decode(LineSplitter.split(source).join())
        .reversed
        .map((e) => e.toRadixString(16).padLeft(2, '0'))
        .join();