// Service worker: la app abre sin conexión (shell en caché) y los capítulos guardados "en este
// dispositivo" (caché OFFLINE, la llena app.js) se leen sin red.
const SHELL = 'shell-v1'
const OFFLINE = 'offline-v1'
const SHELL_FILES = ['/', '/app.js', '/style.css', '/icon.svg', '/manifest.webmanifest', '/icon-192.png', '/icon-512.png']

self.addEventListener('install', e => {
  e.waitUntil(caches.open(SHELL).then(c => c.addAll(SHELL_FILES)).then(() => self.skipWaiting()))
})
self.addEventListener('activate', e => {
  e.waitUntil(caches.keys()
    .then(keys => Promise.all(keys.filter(k => k !== SHELL && k !== OFFLINE).map(k => caches.delete(k))))
    .then(() => self.clients.claim()))
})

// Red primero (así siempre se ve la última versión) y la caché si no hay conexión.
async function networkFirst(req, cacheName, { store = true, ignoreSearch = false, fallback } = {}) {
  try {
    const res = await fetch(req)
    if (store && res.ok) {
      const c = await caches.open(cacheName)
      if (store === true || (await c.match(req, { ignoreSearch }))) c.put(req, res.clone())
    }
    return res
  } catch (err) {
    const hit = await caches.match(req, { ignoreSearch, cacheName }) || (fallback && await caches.match(fallback))
    if (hit) return hit
    throw err
  }
}

self.addEventListener('fetch', e => {
  const req = e.request
  if (req.method !== 'GET') return
  const url = new URL(req.url)
  if (url.origin !== location.origin) return
  const p = url.pathname
  if (req.mode === 'navigate') return e.respondWith(networkFirst(req, SHELL, { fallback: '/' }))
  if (SHELL_FILES.includes(p) || p === '/sw.js') return e.respondWith(networkFirst(req, SHELL))
  if (p === '/api/me') return e.respondWith(networkFirst(req, SHELL))
  // Ficha y capítulo: solo se guardan si el usuario los guardó (store: 'existing' = refrescar si ya estaban).
  if (p.startsWith('/api/manga/')) return e.respondWith(networkFirst(req, OFFLINE, { store: 'existing', ignoreSearch: true }))
  if (p.startsWith('/api/chapter/')) return e.respondWith(networkFirst(req, OFFLINE, { store: false, ignoreSearch: true }))
  // Imágenes: si están guardadas, sin red (más rápido y sin gastar datos).
  if (p.startsWith('/api/local/') || p.startsWith('/api/img') || p.startsWith('/api/local-cover/')) {
    e.respondWith(caches.open(OFFLINE).then(c => c.match(req)).then(hit => hit || fetch(req)))
  }
})