Fetch deposit BTC address (contract code)

client/src/Deposit.js

@@ -1,9 +1,4 @@
-import {
-  TBTCSystem,
-  TBTCToken,
-  KeepBridge,
-  DepositFactory
-} from './eth/contracts'
+import { DepositFactory, KeepBridge, TBTCSystem, TBTCToken } from './eth/contracts';
 
 /**
  * Creates a new deposit and returns its address
@@ -32,6 +27,5 @@ export async function createDeposit() {
   })
 
   const depositAddress = logs[0].args.depositCloneAddress
-
   return depositAddress
 }

client/src/FundingTransaction.js

@@ -1,24 +1,67 @@
-// PAGE 3: Pay BTC
-async function getAddress(depositAddress) {
-  // TODO: Implement:
-  // 1. Get keep public key from the deposit
-  // 2. Calculate P2WPKH address from the key
+import { Network, publicKeyToP2WPKHaddress } from 'tbtc-helpers/src/Address';
+import { Deposit, TBTCSystem } from './eth/contracts';
+
+/**
+ * Requests a Bitcoin public key for a Deposit and returns it as a Bitcoin address
+ * @param {string} depositAddress the address of a Deposit contract
+ * @return {string} a bech32-encoded Bitcoin address, generated from a SegWit P2WPKH script
+ */
+export async function getDepositBtcAddress(depositAddress) {
+  const tbtcSystem = await TBTCSystem.deployed()
+
+  // 1. Request public key from the deposit
+  const deposit = await Deposit.at(depositAddress)
+
+  console.log(`Call getPublicKey for deposit [${deposit.address}]`)
+
+  await deposit.retrieveSignerPubkey()
+    .catch((err)=> {
+      // This can happen when the public key was already retrieved before 
+      // and we may succeed to get it with tbtcSystem.getPastEvents in the following lines
+      // TODO: there may be other errors that this allows to pass, refactor in future
+      console.error(`retrieveSignerPubkey failed: ${err}`)
+    })
+
+  // 2. Parse the logs to get the public key
+  // since the public key event is emitted in another contract, we
+  // can't get this from result.logs
+  const eventList = await tbtcSystem.getPastEvents(
+    'RegisteredPubkey', 
+    {
+      fromBlock: '0',
+      toBlock: 'latest',
+      filter: { _depositContractAddress: depositAddress }
+    }
+  )
+
+  if(eventList.length == 0) {
+    throw new Error(`couldn't find RegisteredPubkey event for deposit address: ${depositAddress}`)
+  }
+
+  let publicKeyX = eventList[0].args._signingGroupPubkeyX
+  let publicKeyY = eventList[0].args._signingGroupPubkeyY
+  publicKeyX = publicKeyX.replace('0x', '')
+  publicKeyY = publicKeyY.replace('0x', '')
+
+  console.log(`Registered public key for deposit ${depositAddress}:\nX: ${publicKeyX}\nY: ${publicKeyY}`)
+
+  const btcAddress = publicKeyToP2WPKHaddress(
+    `${publicKeyX}${publicKeyY}`,
+    Network.testnet
+  )
+  return btcAddress
 }
 
 // Transition from PAGE 3 to PAGE 4
 // 1. Wait for transaction on chain
 // 2. Return transaction ID
-async function getFundingTransactionID(electrumConfig, bitcoinAddress) {
+export async function getFundingTransactionID(electrumConfig, bitcoinAddress) {
   // TODO: Implement
 }
 
 // PAGE 4. WAITING FOR CONFIRMATIONS
-async function waitForConfirmations(transactionID) {
+export async function waitForConfirmations(transactionID) {
   // TODO: Implement:
   // 1. Wait for required number of confirmations for the transaction
   // 2. Monitor confirmations on the chain and return when ready
-}
-
-module.exports = {
-  getAddress, getFundingTransactionID, waitForConfirmations,
-}
+}