feat: implement pwa push notifications

lib/push.ts

@@ -0,0 +1,37 @@
+import webpush from 'web-push';
+
+if (!process.env.NEXT_PUBLIC_VAPID_PUBLIC_KEY || !process.env.VAPID_PRIVATE_KEY) {
+    console.warn("VAPID keys are missing. Push notifications will not work.");
+} else {
+    webpush.setVapidDetails(
+        process.env.VAPID_SUBJECT || 'mailto:admin@localhost',
+        process.env.NEXT_PUBLIC_VAPID_PUBLIC_KEY,
+        process.env.VAPID_PRIVATE_KEY
+    );
+}
+
+interface PushSubscriptionData {
+    endpoint: string;
+    p256dh: string;
+    auth: string;
+}
+
+export async function sendPushNotification(subscription: PushSubscriptionData, payload: any) {
+    try {
+        await webpush.sendNotification({
+            endpoint: subscription.endpoint,
+            keys: {
+                p256dh: subscription.p256dh,
+                auth: subscription.auth,
+            }
+        }, JSON.stringify(payload));
+        return { success: true, statusCode: 201 };
+    } catch (error: any) {
+        if (error.statusCode === 410 || error.statusCode === 404) {
+            // Subscription is gone
+            return { success: false, statusCode: error.statusCode };
+        }
+        console.error("Error sending push:", error);
+        return { success: false, statusCode: error.statusCode || 500 };
+    }
+}