Added loading indicator

src/lib/components/GoogleAuthButton.svelte

@@ -21,8 +21,8 @@
 	let authState = $state(createGoogleAuthState());
 	let authManager = new GoogleAuthManager(authState);
 
-	onMount(() => {
-		authManager.checkConnection();
+	onMount(async () => {
+		await authManager.checkConnection();
 	});
 
 	async function handleConnect() {
@@ -57,7 +57,14 @@
 	};
 </script>
 
-{#if authState.isConnected}
+{#if authState.checking}
+	<div class="flex items-center gap-3">
+		<div class="flex items-center gap-2 rounded-full bg-gray-100 px-3 py-1 border border-gray-300 whitespace-nowrap">
+			<div class="w-4 h-4 animate-spin rounded-full border-2 border-current border-t-transparent text-gray-600"></div>
+			<span class="text-sm font-medium text-gray-800">Checking connection...</span>
+		</div>
+	</div>
+{:else if authState.isConnected}
 	<div class="flex flex-wrap items-center gap-3">
 		<div class="flex items-center gap-2 rounded-full bg-green-100 px-3 py-1 border border-green-300 whitespace-nowrap">
 			<svg xmlns="http://www.w3.org/2000/svg" class="h-4 w-4 text-green-600" viewBox="0 0 20 20" fill="currentColor">

src/lib/google/auth/manager.ts

@@ -30,7 +30,7 @@ export class GoogleAuthManager {
 		this.state = state;
 	}
 
-	checkConnection(): void {
+	async checkConnection(): Promise<void> {
 		this.state.checking = true;
 		this.state.error = null;
 
@@ -38,12 +38,39 @@ export class GoogleAuthManager {
 			const token = localStorage.getItem('google_refresh_token');
 			const email = localStorage.getItem('google_user_email');
 
-			this.state.isConnected = !!token;
-			this.state.token = token;
-			this.state.userEmail = email;
+			if (!token) {
+				this.state.isConnected = false;
+				this.state.token = null;
+				this.state.userEmail = null;
+				return;
+			}
+
+			// Verify the token by calling our backend endpoint
+			const response = await fetch('/private/api/google/auth/check', {
+				method: 'POST',
+				headers: {
+					'Content-Type': 'application/json'
+				},
+				body: JSON.stringify({ refreshToken: token })
+			});
+
+			if (response.ok) {
+				this.state.isConnected = true;
+				this.state.token = token;
+				this.state.userEmail = email;
+			} else {
+				// Token is invalid or expired
+				await this.disconnectGoogle();
+				if (response.status === 401) {
+					this.state.error = 'Google session expired. Please reconnect.';
+				} else {
+					this.state.error = 'Failed to verify connection.';
+				}
+			}
 		} catch (error) {
 			console.error('Error checking connection:', error);
-			this.state.error = 'Failed to check connection status';
+			this.state.error = 'Failed to verify connection status';
+			this.state.isConnected = false;
 		} finally {
 			this.state.checking = false;
 		}

src/routes/private/api/google/auth/check/+server.ts

@@ -0,0 +1,32 @@
+import { json } from '@sveltejs/kit';
+import { getAuthenticatedClient } from '$lib/google/auth/server';
+
+/**
+ * @description Verify the validity of a Google refresh token
+ * @method POST
+ * @param {Request} request
+ * @returns {Response}
+ */
+export async function POST({ request }: { request: Request }): Promise<Response> {
+	try {
+		const { refreshToken } = await request.json();
+
+		if (!refreshToken) {
+			return json({ error: 'Refresh token is required' }, { status: 400 });
+		}
+
+		// Get an authenticated client. This will attempt to get a new access token,
+		// which effectively validates the refresh token.
+		const oauth2Client = getAuthenticatedClient(refreshToken);
+
+		// Attempt to get a new access token
+		await oauth2Client.getAccessToken();
+
+		// If no error is thrown, the token is valid
+		return json({ success: true });
+	} catch (error) {
+		console.error('Failed to verify Google refresh token:', error);
+		// The token is likely invalid or revoked
+		return json({ error: 'Invalid or expired refresh token' }, { status: 401 });
+	}
+}