From bfe489d920c2095a6e724efdc790f88345eba72d Mon Sep 17 00:00:00 2001
From: MOHAN <mohan326856@gmail.com>
Date: Wed, 15 Jul 2026 21:08:06 +0530
Subject: [PATCH] Refactor GoogleService: streamline token handling and improve
 comments

---
 src/google/google.service.ts | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/src/google/google.service.ts b/src/google/google.service.ts
index 2656e58..15817b8 100644
--- a/src/google/google.service.ts
+++ b/src/google/google.service.ts
@@ -1,6 +1,5 @@
 import { BadRequestException, Injectable, Logger } from "@nestjs/common";
 import { google } from "googleapis";
-import { Credentials } from "google-auth-library";
 import { PrismaService } from "../prisma/prisma.service";
 
 const SCOPES = [
@@ -31,19 +30,18 @@ export class GoogleService {
     const authUrl = client.generateAuthUrl({
       access_type: "offline",
       scope: SCOPES,
-      prompt: "consent",
-      state: userId,
+      prompt: "consent", // always request a refresh_token
+      state: userId,     // passed back in callback to identify the user
     });
     return { authUrl };
   }
 
   async exchangeCode(userId: string, code: string) {
     const client = this.createClient();
-    let tokens: Credentials;
-
+    let tokens: import("google-auth-library").Credentials;
     try {
-      const { tokens: t } = await client.getToken(code);
-      tokens = t;
+      const result = await client.getToken(code);
+      tokens = result.tokens;
     } catch {
       throw new BadRequestException("Invalid or expired authorization code.");
     }
@@ -54,6 +52,7 @@ export class GoogleService {
       );
     }
 
+    // Fetch the Google account email
     client.setCredentials(tokens);
     const oauth2 = google.oauth2({ version: "v2", auth: client });
     const { data } = await oauth2.userinfo.get();
@@ -67,7 +66,7 @@ export class GoogleService {
         accessToken: tokens.access_token ?? null,
         isConnected: true,
         connectedAt: new Date(),
-        spreadsheetId: null,
+        spreadsheetId: null, // reset so a new spreadsheet is created on next export
       },
       create: {
         userId,
@@ -92,4 +91,4 @@ export class GoogleService {
     if (!gc || !gc.isConnected) return { connected: false };
     return { connected: true, googleEmail: gc.googleEmail, connectedAt: gc.connectedAt };
   }
-}
\ No newline at end of file
+}