Auto-redirect single auth provider OIDC installations to login

closes #6167

app/scenes/Login/components/AuthenticationProvider.tsx

@@ -2,14 +2,12 @@ import { EmailIcon } from "outline-icons";
 import * as React from "react";
 import { useTranslation } from "react-i18next";
 import styled from "styled-components";
-import { Client } from "@shared/types";
-import { parseDomain } from "@shared/utils/domains";
 import ButtonLarge from "~/components/ButtonLarge";
 import InputLarge from "~/components/InputLarge";
 import PluginIcon from "~/components/PluginIcon";
-import env from "~/env";
 import { client } from "~/utils/ApiClient";
 import Desktop from "~/utils/Desktop";
+import { getRedirectUrl } from "../getRedirectUrl";
 
 type Props = {
   id: string;
@@ -19,25 +17,6 @@ type Props = {
   onEmailSuccess: (email: string) => void;
 };
 
-function useRedirectHref(authUrl: string) {
-  // If we're on a custom domain or a subdomain then the auth must point to the
-  // apex (env.URL) for authentication so that the state cookie can be set and read.
-  // We pass the host into the auth URL so that the server can redirect on error
-  // and keep the user on the same page.
-  const { custom, teamSubdomain, host } = parseDomain(window.location.origin);
-  const url = new URL(env.URL);
-  url.pathname = authUrl;
-
-  if (custom || teamSubdomain) {
-    url.searchParams.set("host", host);
-  }
-  if (Desktop.isElectron()) {
-    url.searchParams.set("client", Client.Desktop);
-  }
-
-  return url.toString();
-}
-
 function AuthenticationProvider(props: Props) {
   const { t } = useTranslation();
   const [showEmailSignin, setShowEmailSignin] = React.useState(false);
@@ -76,7 +55,7 @@ function AuthenticationProvider(props: Props) {
     }
   };
 
-  const href = useRedirectHref(authUrl);
+  const href = getRedirectUrl(authUrl);
 
   if (id === "email") {
     if (isCreate) {