'use strict';

/* Minimal service worker: caches the shell so the PWA is installable.
   Never touches /api/* (live data + SSE streams). Network-first, so open
   dashboards always run the latest shell when the server is reachable. */

const CACHE = 'proddash-v1';
const SHELL = [
  '/',
  '/style.css',
  '/shell.js',
  '/manifest.webmanifest',
  '/icons/icon-192.png',
  '/icons/icon-512.png',
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE).then((cache) => cache.addAll(SHELL)).then(() => self.skipWaiting())
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys()
      .then((keys) => Promise.all(keys.filter((k) => k !== CACHE).map((k) => caches.delete(k))))
      .then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url);
  if (event.request.method !== 'GET' || url.pathname.startsWith('/api/')) return;

  // Network first, cache fallback
  event.respondWith(
    fetch(event.request)
      .then((res) => {
        const copy = res.clone();
        caches.open(CACHE).then((cache) => cache.put(event.request, copy));
        return res;
      })
      .catch(() => caches.match(event.request, { ignoreSearch: true }))
  );
});