// The Nexus — Service Worker
// Cache-first for assets, network-first for API calls

const CACHE_NAME = 'nexus-v1';
const ASSET_CACHE = 'nexus-assets-v1';

const CORE_ASSETS = [
  '/',
  '/index.html',
  '/app.js',
  '/style.css',
  '/manifest.json',
  '/ws-client.js',
  'https://unpkg.com/three@0.183.0/build/three.module.js',
  'https://unpkg.com/three@0.183.0/examples/jsm/controls/OrbitControls.js',
  'https://unpkg.com/three@0.183.0/examples/jsm/postprocessing/EffectComposer.js',
  'https://unpkg.com/three@0.183.0/examples/jsm/postprocessing/RenderPass.js',
  'https://unpkg.com/three@0.183.0/examples/jsm/postprocessing/UnrealBloomPass.js',
  'https://unpkg.com/three@0.183.0/examples/jsm/postprocessing/ShaderPass.js',
  'https://unpkg.com/three@0.183.0/examples/jsm/shaders/CopyShader.js',
  'https://unpkg.com/three@0.183.0/examples/jsm/shaders/LuminosityHighPassShader.js',
];

// Install: precache core assets
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(ASSET_CACHE).then((cache) => cache.addAll(CORE_ASSETS))
      .then(() => self.skipWaiting())
  );
});

// Activate: clean up old caches
self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((keys) =>
      Promise.all(
        keys
          .filter((key) => key !== CACHE_NAME && key !== ASSET_CACHE)
          .map((key) => caches.delete(key))
      )
    ).then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', (event) => {
  const { request } = event;
  const url = new URL(request.url);

  // Network-first for API calls (Gitea / WebSocket upgrades / portals.json live data)
  if (
    url.pathname.startsWith('/api/') ||
    url.hostname.includes('143.198.27.163') ||
    request.headers.get('Upgrade') === 'websocket'
  ) {
    event.respondWith(networkFirst(request));
    return;
  }

  // Cache-first for everything else (local assets + CDN)
  event.respondWith(cacheFirst(request));
});

async function cacheFirst(request) {
  const cached = await caches.match(request);
  if (cached) return cached;

  try {
    const response = await fetch(request);
    if (response.ok) {
      const cache = await caches.open(ASSET_CACHE);
      cache.put(request, response.clone());
    }
    return response;
  } catch {
    // Offline and not cached — return a minimal fallback for navigation
    if (request.mode === 'navigate') {
      const fallback = await caches.match('/index.html');
      if (fallback) return fallback;
    }
    return new Response('Offline', { status: 503, statusText: 'Service Unavailable' });
  }
}

async function networkFirst(request) {
  try {
    const response = await fetch(request);
    if (response.ok) {
      const cache = await caches.open(CACHE_NAME);
      cache.put(request, response.clone());
    }
    return response;
  } catch {
    const cached = await caches.match(request);
    return cached || new Response('Offline', { status: 503, statusText: 'Service Unavailable' });
  }
}