16185 and 16630 language switching

pages/auth/error.js

@@ -7,6 +7,8 @@ import CookieBanner from "../../components/cookieBanner";
 import Footer from "../../components/footer";
 import Header from "../../components/header";
 import ServiceBanner from "../../components/servicebanner";
+import { destroyCookie, setCookie } from "nookies";
+import { useEffect } from "react";
 
 import { getCsrfToken } from "next-auth/react";
 
@@ -16,6 +18,14 @@ const Error = (props) => {
 
     const { error } = useRouter().query;
 
+    useEffect(() => {
+        window.localStorage.clear(),
+            destroyCookie(null, "next-auth.csrf-token", { path: "/" }),
+            destroyCookie(null, "next-auth.callback-url", { path: "/" }),
+            destroyCookie(null, "pedw_locale", { path: "/" }),
+            destroyCookie(null, "pinsUser", { path: "/" });
+    }, []);
+
     const errors = {
         Signin: t("auth:auth-error-Signin-label"),
         OAuthSignin: t("auth:auth-error-OAuthSignin-label"),

pages/auth/signin.js

@@ -7,6 +7,8 @@ import CookieBanner from "../../components/cookieBanner";
 import Footer from "../../components/footer";
 import Header from "../../components/header";
 import ServiceBanner from "../../components/servicebanner";
+import { getPreferredLanguage } from "../../actions";
+import { setCookie } from "nookies";
 
 const SignIn = (props) => {
     let { t, lang } = useTranslation();
@@ -25,6 +27,35 @@ const SignIn = (props) => {
     const handleSubmit = async (event) => {
         event.preventDefault();
         setButtonDisabled(true);
+
+        const email = event.target.email.value;
+
+        try {
+            const res = await getPreferredLanguage(encodeURIComponent(email));
+            const data = await res;
+
+            const userLang =
+                data.value.length > 0
+                    ? data.value[0].pinswg_preferredlanguage === 846040000
+                        ? "cy"
+                        : "en"
+                    : "en";
+
+            // Modify callbackUrl hidden input to add/update lang param
+            const url = new URL(event.target.callbackUrl.value);
+            url.searchParams.set("locale", userLang);
+
+            setCookie(null, "pedw_locale", userLang, {
+                path: "/",
+                maxAge: 60 * 60 * 24 * 365,
+            });
+
+            event.target.callbackUrl.value = url.toString();
+        } catch (error) {
+            console.error("Failed to get preferred language", error);
+        }
+
+        // Submit form after updating callbackUrl
         event.target.submit();
     };