finance_app/app/Http/Controllers/Auth/GoogleAuthController.php

<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use App\Models\User;
use Illuminate\Support\Facades\Auth;
use Laravel\Socialite\Facades\Socialite;

class GoogleAuthController extends Controller
{
    // 導向 Google 登入頁
    public function redirect()
    {
        return Socialite::driver('google')
            ->scopes(['https://www.googleapis.com/auth/gmail.readonly'])
            ->with([
                'access_type' => 'offline',   // 💡 極其重要：強制要求 Google 回傳長期有效的 refresh_token
                'prompt' => 'consent'    // 💡 強制跳出授權提示，確保每次都能順利拿到憑證
            ])
            ->redirect();
    }

    // Google 打回來後處理
    public function callback()
    {
        $googleUser = Socialite::driver('google')->stateless()->user();

        $user = User::updateOrCreate(
            ['email' => $googleUser->getEmail()],
            [
                'name' => $googleUser->getName(),
                'google_id' => $googleUser->getId(),
                'avatar' => $googleUser->getAvatar(),
                'password' => bcrypt(str()->random(24)),
                'google_access_token' => $googleUser->token,
                'google_refresh_token' => $googleUser->refreshToken, // 💡 只有第一次授權或加了 prompt=consent 才會給
                'google_token_expires_at' => now()->addSeconds($googleUser->expiresIn),
            ]
        );

        if ($googleUser->refreshToken) {
            $user->update(['google_refresh_token' => $googleUser->refreshToken]);
        }

        $token = $user->createToken('auth_token')->plainTextToken;

        // 把 token 帶回前端
        return redirect(env('APP_URL') . "/#/auth/callback?token={$token}&name=" . urlencode($user->name));
    }
}