From d03bf1ec299e185c9a9fa584a2c896dc3da8fb6a Mon Sep 17 00:00:00 2001
From: lukaw3d <lukajeran@oasislabs.com>
Date: Fri, 12 May 2023 03:32:23 +0200
Subject: [PATCH] Prevent freezing UI rendering while pre-deriving accounts
 from mnemonic

---
 src/app/state/importaccounts/saga.test.ts | 2 ++
 src/app/state/importaccounts/saga.ts      | 5 ++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/app/state/importaccounts/saga.test.ts b/src/app/state/importaccounts/saga.test.ts
index 7282df6e47..af2e5fef36 100644
--- a/src/app/state/importaccounts/saga.test.ts
+++ b/src/app/state/importaccounts/saga.test.ts
@@ -11,6 +11,7 @@ import { ImportAccountsListAccount, ImportAccountsStep } from './types'
 import { WalletErrors } from 'types/errors'
 import { OasisTransaction } from 'app/lib/transaction'
 import { WalletType } from 'app/state/wallet/types'
+import delayP from '@redux-saga/delay-p'
 
 describe('importAccounts Sagas', () => {
   describe('enumerateAccountsFromLedger', () => {
@@ -123,6 +124,7 @@ describe('importAccounts Sagas', () => {
           ],
           [matchers.call.fn(publicKeyToAddress), mockAddress],
           [matchers.call.fn(getBalance), {}],
+          [matchers.call.fn(delayP), null], // https://github.com/jfairbank/redux-saga-test-plan/issues/257
         ])
         .dispatch(importAccountsActions.enumerateAccountsFromMnemonic('mnemonic'))
         .put(importAccountsActions.setStep(ImportAccountsStep.LoadingAccounts))
diff --git a/src/app/state/importaccounts/saga.ts b/src/app/state/importaccounts/saga.ts
index acf8853467..2243d8a665 100644
--- a/src/app/state/importaccounts/saga.ts
+++ b/src/app/state/importaccounts/saga.ts
@@ -4,7 +4,7 @@ import * as oasis from '@oasisprotocol/client'
 import { hex2uint, publicKeyToAddress, uint2hex } from 'app/lib/helpers'
 import { Ledger, LedgerSigner } from 'app/lib/ledger'
 import { OasisTransaction } from 'app/lib/transaction'
-import { all, call, fork, put, select, takeEvery } from 'typed-redux-saga'
+import { all, call, delay, fork, put, select, takeEvery } from 'typed-redux-saga'
 import { ErrorPayload, WalletError, WalletErrors } from 'types/errors'
 import { WalletType } from 'app/state/wallet/types'
 import { importAccountsActions } from '.'
@@ -66,6 +66,7 @@ function* enumerateAccountsFromMnemonic(action: PayloadAction<string>) {
 
   try {
     yield* setStep(ImportAccountsStep.LoadingAccounts)
+    // Pre-derive all pages of accounts so we don't need to store mnemonic in redux.
     for (let i = 0; i < accountsPerPage * numberOfAccountPages; i++) {
       const signer = yield* call(oasis.hdkey.HDKey.getAccountSigner, mnemonic, i)
       const address = yield* call(publicKeyToAddress, signer.publicKey)
@@ -79,6 +80,8 @@ function* enumerateAccountsFromMnemonic(action: PayloadAction<string>) {
         selected: i === 0,
         type: WalletType.Mnemonic,
       })
+      // Prevent freezing UI rendering. Especially noticeable on a phone.
+      yield* delay(0)
     }
     yield* put(importAccountsActions.accountsListed(wallets))
     yield* setStep(ImportAccountsStep.Idle)