BlueWallet/class/hd-segwit-p2sh-wallet.js

import { AbstractHDWallet } from './abstract-hd-wallet';
import Frisbee from 'frisbee';
const bitcoin = require('bitcoinjs-lib');
const bip39 = require('bip39');
const BigNumber = require('bignumber.js');
const b58 = require('bs58check');

/**
 * HD Wallet (BIP39).
 * In particular, BIP49 (P2SH Segwit)
 * @see https://github.com/bitcoin/bips/blob/master/bip-0049.mediawiki
 */
export class HDSegwitP2SHWallet extends AbstractHDWallet {
  constructor() {
    super();
    this.type = 'HDsegwitP2SH';
    this.usedAddresses = [];
  }

  getTypeReadable() {
    return 'HD SegWit (BIP49 P2SH)';
  }

  async fetchBalance() {
    try {
      const api = new Frisbee({ baseURI: 'https://www.blockonomics.co' });
      let response = await api.post('/api/balance', { body: JSON.stringify({ addr: this.getXpub() }) });
      // console.log(response);

      if (response && response.body && response.body.response) {
        this.balance = 0;
        this.unconfirmed_balance = 0;
        this.usedAddresses = [];
        for (let addr of response.body.response) {
          this.balance += addr.confirmed;
          this.unconfirmed_balance += addr.unconfirmed;
          this.usedAddresses.push(addr.addr);
        }
        this.balance = new BigNumber(this.balance).div(100000000).toString() * 1;
        this.unconfirmed_balance = new BigNumber(this.unconfirmed_balance).div(100000000).toString() * 1;
        this._lastBalanceFetch = +new Date();
      } else {
        throw new Error('Could not fetch balance from API: ' + response.err);
      }
    } catch (err) {
      console.warn(err);
    }
  }

  _getExternalWIFByIndex(index) {
    index = index * 1; // cast to int
    let mnemonic = this.secret;
    let seed = bip39.mnemonicToSeed(mnemonic);
    let root = bitcoin.HDNode.fromSeedBuffer(seed);
    let path = "m/49'/0'/0'/0/" + index;
    let child = root.derivePath(path);
    return child.keyPair.toWIF();
  }

  _getInternalWIFByIndex(index) {
    index = index * 1; // cast to int
    let mnemonic = this.secret;
    let seed = bip39.mnemonicToSeed(mnemonic);
    let root = bitcoin.HDNode.fromSeedBuffer(seed);
    let path = "m/49'/0'/0'/1/" + index;
    let child = root.derivePath(path);
    return child.keyPair.toWIF();
  }

  _getExternalAddressByIndex(index) {
    index = index * 1; // cast to int
    if (this.external_addresses_cache[index]) return this.external_addresses_cache[index]; // cache hit
    let mnemonic = this.secret;
    let seed = bip39.mnemonicToSeed(mnemonic);
    let root = bitcoin.HDNode.fromSeedBuffer(seed);
    let path = "m/49'/0'/0'/0/" + index;
    let child = root.derivePath(path);

    let keyhash = bitcoin.crypto.hash160(child.getPublicKeyBuffer());
    let scriptSig = bitcoin.script.witnessPubKeyHash.output.encode(keyhash);
    let addressBytes = bitcoin.crypto.hash160(scriptSig);
    let outputScript = bitcoin.script.scriptHash.output.encode(addressBytes);
    return (this.external_addresses_cache[index] = bitcoin.address.fromOutputScript(outputScript, bitcoin.networks.bitcoin));
  }

  _getInternalAddressByIndex(index) {
    index = index * 1; // cast to int
    if (this.internal_addresses_cache[index]) return this.internal_addresses_cache[index]; // cache hit
    let mnemonic = this.secret;
    let seed = bip39.mnemonicToSeed(mnemonic);
    let root = bitcoin.HDNode.fromSeedBuffer(seed);

    let path = "m/49'/0'/0'/1/" + index;
    let child = root.derivePath(path);

    let keyhash = bitcoin.crypto.hash160(child.getPublicKeyBuffer());
    let scriptSig = bitcoin.script.witnessPubKeyHash.output.encode(keyhash);
    let addressBytes = bitcoin.crypto.hash160(scriptSig);
    let outputScript = bitcoin.script.scriptHash.output.encode(addressBytes);
    return (this.internal_addresses_cache[index] = bitcoin.address.fromOutputScript(outputScript, bitcoin.networks.bitcoin));
  }

  /**
   * Returning ypub actually, not xpub. Keeping same method name
   * for compatibility.
   *
   * @return {String} ypub
   */
  getXpub() {
    if (this._xpub) {
      return this._xpub; // cache hit
    }
    // first, getting xpub
    let mnemonic = this.secret;
    let seed = bip39.mnemonicToSeed(mnemonic);
    let root = bitcoin.HDNode.fromSeedBuffer(seed);

    let path = "m/49'/0'/0'";
    let child = root.derivePath(path).neutered();
    let xpub = child.toBase58();

    // bitcoinjs does not support ypub yet, so we just convert it from xpub
    let data = b58.decode(xpub);
    data = data.slice(4);
    data = Buffer.concat([Buffer.from('049d7cb2', 'hex'), data]);
    this._xpub = b58.encode(data);
    return this._xpub;
  }

  /**
   * @inheritDoc
   */
  async fetchTransactions() {
    try {
      if (this.usedAddresses.length === 0) {
        // just for any case, refresh balance (it refreshes internal `this.usedAddresses`)
        await this.fetchBalance();
      }

      let addresses = this.usedAddresses.join('|');

      const api = new Frisbee({ baseURI: 'https://blockchain.info' });
      this.transactions = [];
      let offset = 0;

      while (1) {
        let response = await api.get('/multiaddr?active=' + addresses + '&n=100&offset=' + offset);

        if (response && response.body) {
          if (response.body.txs && response.body.txs.length === 0) {
            break;
          }

          // processing TXs and adding to internal memory
          if (response.body.txs) {
            for (let tx of response.body.txs) {
              let value = 0;

              for (let input of tx.inputs) {
                // ----- INPUTS

                if (input.prev_out && input.prev_out.addr && this.weOwnAddress(input.prev_out.addr)) {
                  // this is outgoing from us
                  value -= input.prev_out.value;
                }
              }

              for (let output of tx.out) {
                // ----- OUTPUTS

                if (output.addr && this.weOwnAddress(output.addr)) {
                  // this is incoming to us
                  value += output.value;
                }
              }

              tx.value = value; // new BigNumber(value).div(100000000).toString() * 1;

              this.transactions.push(tx);
            }

            if (response.body.txs.length < 100) {
              // this fetch yilded less than page size, thus requesting next batch makes no sense
              break;
            }
          } else {
            break; // error ?
          }
        } else {
          throw new Error('Could not fetch transactions from API: ' + response.err); // breaks here
        }

        offset += 100;
      }
    } catch (err) {
      console.warn(err);
    }
  }

  weOwnAddress(addr) {
    let hashmap = {};
    for (let a of this.usedAddresses) {
      hashmap[a] = 1;
    }

    return hashmap[addr] === 1;
  }
}