- integrating sign in with google

- set up dark mode context and other services

src/contexts/UserContext.js

@@ -0,0 +1,52 @@
+import React, { createContext, useState, useEffect } from "react";
+import { useAuthState } from "react-firebase-hooks/auth";
+import firebase from "gatsby-plugin-firebase";
+import { toast } from "react-toastify";
+
+const defaultState = {
+  user: null,
+  logout: () => {},
+  loginWithGoogle: async () => {},
+};
+
+const UserContext = createContext(defaultState);
+
+const UserProvider = ({ children }) => {
+  const [firebaseUser, loading] = useAuthState(firebase.auth());
+  const [user, setUser] = useState(null);
+
+  useEffect(() => {
+    setUser(firebaseUser);
+  }, [firebaseUser]);
+
+  const loginWithGoogle = async () => {
+    const provider = new firebase.auth.GoogleAuthProvider();
+
+    try {
+      await firebase.auth().signInWithPopup(provider);
+    } catch (error) {
+      toast.error(error.message);
+    }
+  };
+
+  const logout = () => {
+    firebase.auth().signOut();
+  };
+
+  return (
+    <UserContext.Provider
+      value={{
+        user,
+        loading,
+        logout,
+        loginWithGoogle,
+      }}
+    >
+      {children}
+    </UserContext.Provider>
+  );
+};
+
+export default UserContext;
+
+export { UserProvider };