feat: Support dark mode in login pages (#7420)

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

app/javascript/v3/helpers/AuthHelper.js

@@ -0,0 +1,38 @@
+import Cookies from 'js-cookie';
+import { DEFAULT_REDIRECT_URL } from 'dashboard/constants/globals';
+import { frontendURL } from 'dashboard/helper/URLHelper';
+
+export const hasAuthCookie = () => {
+  return !!Cookies.getJSON('cw_d_session_info');
+};
+
+const getSSOAccountPath = ({ ssoAccountId, user }) => {
+  const { accounts = [], account_id = null } = user || {};
+  const ssoAccount = accounts.find(
+    account => account.id === Number(ssoAccountId)
+  );
+  let accountPath = '';
+  if (ssoAccount) {
+    accountPath = `accounts/${ssoAccountId}`;
+  } else if (accounts.length) {
+    // If the account id is not found, redirect to the first account
+    const accountId = account_id || accounts[0].id;
+    accountPath = `accounts/${accountId}`;
+  }
+  return accountPath;
+};
+
+export const getLoginRedirectURL = ({
+  ssoAccountId,
+  ssoConversationId,
+  user,
+}) => {
+  const accountPath = getSSOAccountPath({ ssoAccountId, user });
+  if (accountPath) {
+    if (ssoConversationId) {
+      return frontendURL(`${accountPath}/conversations/${ssoConversationId}`);
+    }
+    return frontendURL(`${accountPath}/dashboard`);
+  }
+  return DEFAULT_REDIRECT_URL;
+};