Add settings page for alert preferences

public/sw.js

@@ -1,5 +1,5 @@
-const CACHE_NAME = "wtr-shell-v3";
-const SHELL = ["/", "/offline", "/manifest.json", "/icons/icon.svg", "/icons/maskable.svg", "/icons/icon-192.png", "/icons/icon-512.png", "/icons/maskable-512.png"];
+const CACHE_NAME = "wtr-shell-v4";
+const SHELL = ["/", "/settings", "/offline", "/manifest.json", "/icons/icon.svg", "/icons/maskable.svg", "/icons/icon-192.png", "/icons/icon-512.png", "/icons/maskable-512.png"];
 
 self.addEventListener("install", (event) => {
   event.waitUntil(caches.open(CACHE_NAME).then((cache) => cache.addAll(SHELL)));
@@ -32,3 +32,42 @@ self.addEventListener("fetch", (event) => {
     event.respondWith(fetch(event.request).catch(() => caches.match(event.request).then((response) => response || caches.match("/offline"))));
   }
 });
+
+self.addEventListener("push", (event) => {
+  const fallbackPayload = {
+    title: "IMGW",
+    body: "Nowe ostrzeżenie meteorologiczne.",
+    url: "/warnings",
+  };
+  let payload = fallbackPayload;
+  if (event.data) {
+    const text = event.data.text();
+    try {
+      payload = { ...fallbackPayload, ...JSON.parse(text) };
+    } catch {
+      payload = { ...fallbackPayload, body: text };
+    }
+  }
+
+  event.waitUntil(
+    self.registration.showNotification(payload.title, {
+      body: payload.body,
+      icon: "/icons/icon-192.png",
+      badge: "/icons/icon-192.png",
+      data: { url: payload.url || "/warnings" },
+    }),
+  );
+});
+
+self.addEventListener("notificationclick", (event) => {
+  event.notification.close();
+  const targetUrl = new URL(event.notification.data?.url || "/warnings", self.location.origin).href;
+
+  event.waitUntil(
+    self.clients.matchAll({ type: "window", includeUncontrolled: true }).then((clients) => {
+      const existingClient = clients.find((client) => client.url === targetUrl);
+      if (existingClient) return existingClient.focus();
+      return self.clients.openWindow(targetUrl);
+    }),
+  );
+});