refactor: improve script ux

bin/lamassu-eth-recovery

@@ -0,0 +1,61 @@
+#!/usr/bin/env node
+
+const hdkey = require('ethereumjs-wallet/hdkey')
+const hkdf = require('futoin-hkdf')
+const db = require('../lib/db')
+const mnemonicHelpers = require('../lib/mnemonic-helpers')
+
+const pify = require('pify')
+const fs = pify(require('fs'))
+
+const options = require('../lib/options')
+
+const defaultPrefixPath = "m/44'/60'/1'/0'"
+
+const address = process.argv[2]
+
+if (!options || !options.mnemonicPath) {
+  console.error(`Unable to fetch mnemonic from your account!`)
+  process.exit(1)
+}
+
+if (!address) {
+  console.log('Usage: lamassu-eth-recovery <cash-out address>')
+  process.exit(2)
+}
+
+function run (address) {
+  Promise.all([fetchMnemonic(), searchForHdIndex(address)])
+    .then(([mnemonic, hdIndex]) => {
+      try {
+        console.log(`Private key: `, defaultHdNode(mnemonic).deriveChild(hdIndex).getWallet().getPrivateKeyString())
+        process.exit(0)
+      } catch (err) {
+        console.error(`Error while retrieving private key!`)
+        process.exit(3)
+      }
+    })
+}
+
+function searchForHdIndex (address) {
+  const sql = `SELECT hd_index FROM cash_out_txs WHERE to_address = $1`
+  return db.oneOrNone(sql, [address])
+}
+
+function fetchMnemonic () {
+  return fs.readFile(options.mnemonicPath, 'utf8')
+    .then(mnemonic => computeSeed(mnemonic))
+}
+
+function computeSeed (seed) {
+  const masterSeed = mnemonicHelpers.toEntropyBuffer(seed)
+  return hkdf(masterSeed, 32, { salt: 'lamassu-server-salt', info: 'wallet-seed' })
+}
+
+function defaultHdNode (masterSeed) {
+  if (!masterSeed) throw new Error('No master seed!')
+  const key = hdkey.fromMasterSeed(masterSeed)
+  return key.derivePath(defaultPrefixPath)
+}
+
+run(address)