const TILE_CACHE = 'lageplan-tiles-v2'
const STATIC_CACHE = 'lageplan-static-v2'
const APP_CACHE = 'lageplan-app-v2'

// Pre-cache essential app shell on install
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(APP_CACHE).then((cache) =>
      cache.addAll([
        '/app',
        '/logo.svg',
        '/logo-icon.png',
        '/manifest.json',
      ]).catch(() => {})
    )
  )
  self.skipWaiting()
})

// Cache strategy: Network First for API, Cache First for tiles, Stale While Revalidate for static assets
self.addEventListener('fetch', (event) => {
  const url = event.request.url
  const { pathname } = new URL(url)

  // Skip non-GET requests
  if (event.request.method !== 'GET') return

  // API requests: network only (don't cache dynamic data)
  if (pathname.startsWith('/api/')) return

  // Cache map tiles from OpenStreetMap (Cache First)
  if (url.includes('tile.openstreetmap.org') || url.includes('api.maptiler.com')) {
    event.respondWith(
      caches.open(TILE_CACHE).then((cache) =>
        cache.match(event.request).then((cached) => {
          if (cached) return cached
          return fetch(event.request).then((response) => {
            if (response.ok) {
              cache.put(event.request, response.clone())
            }
            return response
          }).catch(() => new Response('', { status: 503 }))
        })
      )
    )
    return
  }

  // Static assets (JS, CSS, images): Stale While Revalidate
  if (pathname.match(/\.(js|css|png|jpg|jpeg|svg|ico|woff2?)$/)) {
    event.respondWith(
      caches.open(STATIC_CACHE).then((cache) =>
        cache.match(event.request).then((cached) => {
          const fetchPromise = fetch(event.request).then((response) => {
            if (response.ok) cache.put(event.request, response.clone())
            return response
          }).catch(() => cached || new Response('', { status: 503 }))
          return cached || fetchPromise
        })
      )
    )
    return
  }

  // App pages: Network First with cache fallback
  if (pathname === '/app' || pathname === '/' || pathname.startsWith('/app')) {
    event.respondWith(
      fetch(event.request).then((response) => {
        if (response.ok) {
          const clone = response.clone()
          caches.open(APP_CACHE).then((cache) => cache.put(event.request, clone))
        }
        return response
      }).catch(() =>
        caches.match(event.request).then((cached) => cached || caches.match('/app'))
      )
    )
    return
  }
})

// Clean old caches on activation
self.addEventListener('activate', (event) => {
  const currentCaches = [TILE_CACHE, STATIC_CACHE, APP_CACHE]
  event.waitUntil(
    caches.keys().then((keys) =>
      Promise.all(
        keys
          .filter((k) => !currentCaches.includes(k))
          .map((k) => caches.delete(k))
      )
    ).then(() => self.clients.claim())
  )
})