google sign in

backend/routes/auth.js

@@ -1,8 +1,11 @@
 const express = require("express");
 const jwt = require("jsonwebtoken");
+const { OAuth2Client } = require("google-auth-library");
 const { User } = require("../models"); // Import from models/index.js to get models with associations
 const router = express.Router();
 
+const googleClient = new OAuth2Client(process.env.GOOGLE_CLIENT_ID);
+
 router.post("/register", async (req, res) => {
   try {
     const { username, email, password, firstName, lastName, phone } = req.body;
@@ -74,4 +77,98 @@ router.post("/login", async (req, res) => {
   }
 });
 
+router.post("/google", async (req, res) => {
+  try {
+    const { idToken } = req.body;
+
+    if (!idToken) {
+      return res.status(400).json({ error: "ID token is required" });
+    }
+
+    // Verify the Google ID token
+    const ticket = await googleClient.verifyIdToken({
+      idToken,
+      audience: process.env.GOOGLE_CLIENT_ID,
+    });
+
+    const payload = ticket.getPayload();
+    const {
+      sub: googleId,
+      email,
+      given_name: firstName,
+      family_name: lastName,
+      picture,
+    } = payload;
+
+    if (!email || !firstName || !lastName) {
+      return res
+        .status(400)
+        .json({ error: "Required user information not provided by Google" });
+    }
+
+    // Check if user exists by Google ID first
+    let user = await User.findOne({
+      where: { providerId: googleId, authProvider: "google" },
+    });
+
+    if (!user) {
+      // Check if user exists with same email but different auth provider
+      const existingUser = await User.findOne({ where: { email } });
+      if (existingUser) {
+        return res.status(409).json({
+          error:
+            "An account with this email already exists. Please use email/password login.",
+        });
+      }
+
+      // Create new user
+      user = await User.create({
+        email,
+        firstName,
+        lastName,
+        authProvider: "google",
+        providerId: googleId,
+        profileImage: picture,
+        username: email.split("@")[0] + "_" + googleId.slice(-6), // Generate unique username
+      });
+    }
+
+    // Generate JWT token
+    const token = jwt.sign({ id: user.id }, process.env.JWT_SECRET, {
+      expiresIn: "7d",
+    });
+
+    res.json({
+      user: {
+        id: user.id,
+        username: user.username,
+        email: user.email,
+        firstName: user.firstName,
+        lastName: user.lastName,
+        profileImage: user.profileImage,
+      },
+      token,
+    });
+  } catch (error) {
+    if (error.message && error.message.includes("Token used too late")) {
+      return res
+        .status(401)
+        .json({ error: "Google token has expired. Please try again." });
+    }
+    if (error.message && error.message.includes("Invalid token")) {
+      return res
+        .status(401)
+        .json({ error: "Invalid Google token. Please try again." });
+    }
+    if (error.message && error.message.includes("Wrong number of segments")) {
+      return res
+        .status(400)
+        .json({ error: "Malformed Google token. Please try again." });
+    }
+    res
+      .status(500)
+      .json({ error: "Failed to authenticate with Google: " + error.message });
+  }
+});
+
 module.exports = router;