feat: implement pwa push notifications

lib/notifications.ts

@@ -21,3 +21,51 @@ export async function sendNotification(webhookUrl: string | null, message: strin
         console.error("Failed to send notification:", error);
     }
 }
+
+import { sendPushNotification } from "./push";
+import prisma from "@/lib/prisma";
+
+export async function sendPlanNotification(planId: string, message: string, webhookUrl?: string | null) {
+    // Parallelize sending
+    const promises: Promise<any>[] = [];
+
+    if (webhookUrl) {
+        promises.push(sendNotification(webhookUrl, message));
+    }
+
+    try {
+        const subscriptions = await prisma.pushSubscription.findMany({
+            where: { planId }
+        });
+
+        if (subscriptions.length > 0) {
+            const payload = {
+                title: "Cat Sitting Planner",
+                body: message,
+                url: `/`
+                // We could pass specific URL if needed, but for now root is okay or dashboard?
+                // The service worker opens the URL.
+                // Ideally, we want to open `/dashboard/[planId]`.
+            };
+
+            // Refine URL in payload
+            // We need 'lang'. We don't have it here easily unless passed.
+            // But we can guess or just link to root and let redirect handle it?
+            // Or just link to context.
+            // Let's rely on SW opening `/`.
+
+            subscriptions.forEach(sub => {
+                promises.push((async () => {
+                    const res = await sendPushNotification(sub, payload);
+                    if (!res.success && (res.statusCode === 410 || res.statusCode === 404)) {
+                        await prisma.pushSubscription.delete({ where: { id: sub.id } });
+                    }
+                })());
+            });
+        }
+    } catch (e) {
+        console.error("Failed to fetch/send push subscriptions", e);
+    }
+
+    await Promise.allSettled(promises);
+}

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 };
+    }
+}