Handle refresh token for google calendar api

functions/package.json

@@ -15,9 +15,10 @@
   },
   "main": "lib/index.js",
   "dependencies": {
-    "firebase-admin": "^12.6.0",
-    "firebase-functions": "^6.0.1",
-    "resend": "^6.9.1"
+    "firebase-admin": "^13.7.0",
+    "firebase-functions": "^7.2.3",
+    "googleapis": "^171.4.0",
+    "resend": "^6.10.0"
   },
   "devDependencies": {
     "@typescript-eslint/eslint-plugin": "^5.12.0",

functions/src/index.ts

@@ -5,6 +5,8 @@ import {
 } from "firebase-functions/v2/https";
 import { defineSecret } from "firebase-functions/params";
 import { Resend } from "resend";
+import { google } from "googleapis";
+import * as admin from "firebase-admin";
 
 // Define the secret
 const resendApiKey = defineSecret("RESEND_API_KEY");
@@ -63,3 +65,130 @@ export const sendEmail = onCall<EmailData>(
     }
   },
 );
+
+const googleClientSecret = defineSecret("GOOGLE_CLIENT_SECRET");
+const googleClientId = "83459975838-fqj9tuogpa17urv03jsaos2nbjfde9ne.apps.googleusercontent.com";
+
+if (!admin.apps.length) {
+  admin.initializeApp();
+}
+
+export const connectCalendar = onCall({
+  secrets: [googleClientSecret],
+  cors: ["http://localhost:3000", "https://studybuddy-392c7.web.app", "https://studybuddy-392c7.firebaseapp.com"],
+}, async (request) => {
+  if (!request.auth) {
+    throw new HttpsError("unauthenticated", "User must be logged in.");
+  }
+
+  const { code } = request.data;
+  const uid = request.auth.uid;
+
+  const oauth2Client = new google.auth.OAuth2(
+    googleClientId,
+    googleClientSecret.value(),
+    "postmessage"
+  );
+
+  try {
+    const { tokens } = await oauth2Client.getToken(code);
+
+    if (tokens.refresh_token) {
+      await admin.firestore().collection("users").doc(uid).set({
+        calendarConnected: true,
+        googleRefreshToken: tokens.refresh_token,
+        updatedAt: new Date().toISOString(), // <-- added ()
+      }, { merge: true });
+    }
+
+    return { success: true };
+  } catch (error) {
+    console.error("Google Token Exchange Error:", error);
+    throw new HttpsError("internal", "Failed to connect Google Calendar");
+  }
+});
+
+export const fetchCalendar = onCall({
+  secrets: [googleClientSecret],
+  cors: ["http://localhost:3000", "https://studybuddy-392c7.web.app", "https://studybuddy-392c7.firebaseapp.com"],
+}, async (request) => {
+  if (!request.auth) {
+    throw new HttpsError("unauthenticated", "User must be logged in.");
+  }
+
+  const uid = request.auth.uid;
+  const db = admin.firestore();
+
+  try {
+    const userDoc = await db.collection("users").doc(uid).get();
+    const refreshToken = userDoc.data()?.googleRefreshToken;
+
+    if (!refreshToken) {
+      throw new HttpsError("not-found", "No calendar token found. Please reconnect.");
+    }
+
+    const oauth2Client = new google.auth.OAuth2(
+      googleClientId,
+      googleClientSecret.value(),
+      "postmessage"
+    );
+
+    oauth2Client.setCredentials({ refresh_token: refreshToken });
+    const calendar = google.calendar({ version: "v3", auth: oauth2Client });
+    const response = await calendar.calendarList.list();
+
+    return { success: true, calendars: response.data.items || [] };
+  } catch (error: any) {
+    console.error("Error fetching calendar:", error);
+
+    if (error.message?.includes("invalid_grant")) {
+      await db.collection("users").doc(uid).update({
+        googleRefreshToken: admin.firestore.FieldValue.delete(),
+        calendarConnected: false,
+      });
+      throw new HttpsError("unauthenticated", "Calendar access revoked. Please reconnect.");
+    }
+
+    if (error instanceof HttpsError) throw error;
+    throw new HttpsError("internal", "Failed to fetch calendars");
+  }
+});
+
+export const fetchEvents = onCall({
+  secrets: [googleClientSecret],
+}, async (request) => {
+  if (!request.auth) {
+    throw new HttpsError("unauthenticated", "User must be logged in.");
+  }
+
+  const uid = request.auth.uid;
+  const { calendarId, timeMin, timeMax, timezone } = request.data;
+  const db = admin.firestore();
+
+  const userDoc = await db.collection("users").doc(uid).get();
+  const refreshToken = userDoc.data()?.googleRefreshToken;
+
+  if (!refreshToken) {
+    throw new HttpsError("not-found", "No calendar token found.");
+  }
+
+  const oauth2Client = new google.auth.OAuth2(
+    googleClientId,
+    googleClientSecret.value(),
+    "postmessage"
+  );
+
+  oauth2Client.setCredentials({ refresh_token: refreshToken });
+  const calendar = google.calendar({ version: "v3", auth: oauth2Client });
+
+  const response = await calendar.events.list({
+    calendarId,
+    timeMin,
+    timeMax,
+    singleEvents: true,
+    orderBy: "startTime",
+    timeZone: timezone,
+  });
+
+  return { success: true, events: response.data.items || [] };
+});

src/backend/firebase.ts

@@ -40,5 +40,5 @@ const db = getFirestore(app);
 export const SCOPES = 'https://www.googleapis.com/auth/calendar.readonly';
 const googleProvider = new GoogleAuthProvider();
 
-export { auth, db, analytics, googleProvider };
+export { auth, db, analytics, googleProvider, app };
 

src/backend/functions.ts

@@ -0,0 +1,10 @@
+import { getFunctions, connectFunctionsEmulator } from 'firebase/functions';
+import { app } from './firebase';
+
+const functions = getFunctions(app);
+
+if (window.location.hostname === 'localhost') {
+  connectFunctionsEmulator(functions, 'localhost', 5001);
+}
+
+export { functions };