// Service Worker for Memos offline support
const CACHE_NAME = "memos-cache-v1";
const RUNTIME_CACHE = "memos-runtime-cache-v1";

// Assets to cache on install
const PRECACHE_ASSETS = [
  "/",
  "/logo.webp",
  "/apple-touch-icon.png",
  "/android-chrome-192x192.png",
  "/android-chrome-512x512.png",
];

// Install event - cache essential assets
self.addEventListener("install", (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      return cache.addAll(PRECACHE_ASSETS).catch((error) => {
        console.error("Failed to cache assets during install:", error);
      });
    })
  );
  self.skipWaiting();
});

// Activate event - cleanup old caches
self.addEventListener("activate", (event) => {
  event.waitUntil(
    caches.keys().then((cacheNames) => {
      return Promise.all(
        cacheNames.map((cacheName) => {
          if (cacheName !== CACHE_NAME && cacheName !== RUNTIME_CACHE) {
            return caches.delete(cacheName);
          }
        })
      );
    })
  );
  self.clients.claim();
});

// Fetch event - network first, fallback to cache
self.addEventListener("fetch", (event) => {
  // Skip cross-origin requests
  if (!event.request.url.startsWith(self.location.origin)) {
    return;
  }

  // Skip non-GET requests
  if (event.request.method !== "GET") {
    return;
  }

  event.respondWith(
    fetch(event.request)
      .then((response) => {
        // Don't cache if not a valid response
        if (!response || response.status !== 200 || response.type === "error") {
          return response;
        }

        // Clone the response
        const responseToCache = response.clone();

        // Cache the fetched response
        caches.open(RUNTIME_CACHE).then((cache) => {
          cache.put(event.request, responseToCache);
        });

        return response;
      })
      .catch(() => {
        // Network failed, try cache
        return caches.match(event.request).then((response) => {
          if (response) {
            return response;
          }

          // If not in cache and offline, return a basic offline page for navigation requests
          if (event.request.mode === "navigate") {
            return caches.match("/");
          }

          return new Response("Offline - resource not available", {
            status: 503,
            statusText: "Service Unavailable",
            headers: new Headers({
              "Content-Type": "text/plain",
            }),
          });
        });
      })
  );
});