added firebase redirect authentication

src/features/auth/AuthMain.test.tsx

@@ -9,18 +9,23 @@ describe("CurrentUserStateIndicator", () => {
     (firestoreAuth.login as jest.Mock).mockClear();
   });
 
-  it("can login", async () => {
+  it("login will set loading ui to prevent double trigger", async () => {
+    (firestoreAuth.login as jest.Mock).mockResolvedValue(
+      new Promise((resolve) => setTimeout(resolve, 500))
+    );
+
     const { store } = fullRender(<AuthMain />);
 
     const loginButtonElement = screen.getByRole("button", {
       name: "Continue with Google",
     });
     await act(() => fireEvent.click(loginButtonElement));
 
-    await waitFor(() => expect(store.getState().user.uid).not.toBe(""));
+    await waitFor(() => expect(store.getState().user.uid).toBe(""));
+    await waitFor(() => expect(screen.getByText("Checking...")).toBeTruthy());
   });
 
-  it("login is integrated with firestore", async () => {
+  it("triggering login will rely on firestore module", async () => {
     fullRender(<AuthMain />);
 
     const loginButtonElement = screen.getByRole("button", {

src/services/firestore-auth.test.ts

@@ -5,8 +5,9 @@ import * as firebaseAuth from "firebase/auth";
 describe("firestoreAuth", () => {
   it("should successfully log in and return user information", async () => {
     jest.spyOn(firebaseAuth, "getAuth");
-    jest.spyOn(firebaseAuth, "signInWithPopup");
-    const user = await firestoreAuth.login();
+    jest.spyOn(firebaseAuth, "getRedirectResult");
+    await firestoreAuth.login();
+    const user = await firestoreAuth.loadUser();
     expect(user).toEqual({
       uid: "abc123def456",
       displayName: "Jane Doe",
@@ -16,7 +17,7 @@ describe("firestoreAuth", () => {
 
   it("should block log in when user email is null", async () => {
     jest.spyOn(firebaseAuth, "getAuth");
-    jest.spyOn(firebaseAuth, "signInWithPopup").mockResolvedValue({
+    jest.spyOn(firebaseAuth, "getRedirectResult").mockResolvedValue({
       operationType: "signIn",
       providerId: "google.com",
       user: {
@@ -39,7 +40,7 @@ describe("firestoreAuth", () => {
         photoURL: "",
       },
     });
-    await expect(firestoreAuth.login()).rejects.toThrow(
+    await expect(firestoreAuth.loadUser()).rejects.toThrow(
       "Login blocked: unidentified user."
     );
   });

src/services/firestore-auth.ts

@@ -3,8 +3,9 @@ import type { User as FirebaseUser } from "firebase/auth";
 import {
   browserLocalPersistence,
   getAuth,
+  getRedirectResult,
   setPersistence,
-  signInWithPopup,
+  signInWithRedirect,
   signOut,
 } from "firebase/auth";
 import { googleAuthProvider } from "./firestore-connection";
@@ -18,54 +19,51 @@ const firestoreAuth = {
 
 export default firestoreAuth;
 
+/** Loads user from redirection result, persistence, whatever. */
 async function loadUser(): Promise<User> {
-  const empty: User = { uid: "", displayName: "", email: "" };
-
-  return new Promise((resolve) => {
-    const done = (user: FirebaseUser | null) => {
-      try {
-        if (user) {
-          const { uid, displayName, email } = user;
-          resolve({
-            uid,
-            displayName: displayName ?? email ?? "",
-            email: email ?? "?@?",
-          });
-        } else {
-          resolve(empty);
-        }
-      } catch (error) {
+  return new Promise((resolve, reject) => {
+    const handleResult = (user: FirebaseUser | null) => {
+      if (!user) {
+        const empty: User = { uid: "", displayName: "", email: "" };
         resolve(empty);
+        return;
+      }
+
+      if (!user.uid || !user.email) {
+        reject(new Error("Login blocked: unidentified user."));
+        return;
       }
+
+      resolve({
+        uid: user.uid,
+        displayName: user.displayName ?? user.email,
+        email: user.email,
+      });
     };
 
-    setTimeout(() => done(null), 3000);
-    getAuth().onAuthStateChanged(once(done));
+    // prepare auth for one of the following events:
+    const auth = getAuth();
+    const onceHandleResult = once(handleResult);
+    // case of timeout (this was specially important for popup method but now not so much)
+    setTimeout(() => onceHandleResult(null), 5 * 1000);
+    // case of loaded by something else (like persistent successfully loaded)
+    auth.onAuthStateChanged(onceHandleResult);
+    // case of got result from redirect flow
+    getRedirectResult(auth)
+      .then((credentials) => credentials?.user || null)
+      .then(onceHandleResult);
   });
 }
 
-async function login(): Promise<User> {
+/** Trigger the login function, it redirects to an authentication page. */
+async function login(): Promise<void> {
   const auth = getAuth();
 
   await setPersistence(auth, browserLocalPersistence);
-
-  const result = await signInWithPopup(auth, googleAuthProvider);
-  const {
-    user: { uid, displayName, email },
-  } = result;
-
-  if (!email) {
-    signOut(auth);
-    throw new Error("Login blocked: unidentified user.");
-  }
-
-  return {
-    uid,
-    displayName: displayName ?? email,
-    email,
-  };
+  await signInWithRedirect(auth, googleAuthProvider);
 }
 
+/** Clears the authentication data. */
 async function logout() {
   signOut(getAuth());
 }

src/state/user.ts

@@ -64,7 +64,7 @@ export const loadUser = createAsyncThunk(
 
 export const login = createAsyncThunk(
   "user/login",
-  () => firestoreAuth.login(),
+  () => firestoreAuth.login().then(firestoreAuth.loadUser),
   {
     condition: (_arg, thunkAPI) =>
       (thunkAPI.getState() as RootState).user.status === "idle",

src/testing-helpers/mock-firebase-auth.ts

@@ -1,7 +1,7 @@
 import type { Auth, AuthProvider } from "firebase/auth";
 
 jest.mock("firebase/auth", () => ({
-  getAuth: jest.fn(),
+  getAuth: jest.fn().mockReturnValue({ onAuthStateChanged: jest.fn() }),
   GoogleAuthProvider: jest.fn(() => ({
     Qc: ["client_id", "response_type", "scope", "redirect_uri", "state"],
     providerId: "google.com",
@@ -13,8 +13,9 @@ jest.mock("firebase/auth", () => ({
   })),
   setPersistence: jest.fn(),
   browserLocalPersistence: jest.fn(),
+  signInWithRedirect: jest.fn(),
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
-  signInWithPopup: jest.fn((_: Auth, __: AuthProvider) =>
+  getRedirectResult: jest.fn((_: Auth, __: AuthProvider) =>
     Promise.resolve({
       operationType: "signIn",
       providerId: "google.com",