const CACHE_NAME = 'jarvis-real-ar-v5'
const BASE_PATH = new URL(self.registration.scope).pathname.replace(/\/?$/, '/')
const shellURL = path => new URL(path, self.registration.scope).href
const START_URL = shellURL('./?device=POCO-M5&mode=vision_pro&source=manifest')
const APP_SHELL = [
  shellURL('./'),
  shellURL('./index.html'),
  shellURL('./manifest.json'),
  START_URL,
  shellURL('./ui/panels.css'),
  shellURL('./ui/mobile.css'),
  shellURL('./ui/hud.css'),
  shellURL('./ui/animations.css'),
]

function isSameOriginAsset(url) {
  return url.origin === self.location.origin
}

function discoverAppAssets(html) {
  if (!html) return []
  const urls = new Set()
  const re = /<(?:script|link)\b[^>]*(?:\ssrc|\shref)=["']([^"']+)["'][^>]*>/gi
  for (const match of html.matchAll(re)) {
    try {
      const url = new URL(match[1], shellURL('./index.html'))
      if (isSameOriginAsset(url)) urls.add(url.href)
    } catch {
      // Ignore malformed asset URLs.
    }
  }
  return [...urls]
}

function discoverDynamicImports(js, baseUrl) {
  if (!js) return []
  const urls = new Set()
  const re = /import\(\s*["']([^"']+)["']\s*\)/g
  for (const match of js.matchAll(re)) {
    try {
      const url = new URL(match[1], baseUrl)
      if (isSameOriginAsset(url)) urls.add(url.href)
    } catch {
      // Ignore malformed dynamic import specifiers.
    }
  }
  return [...urls]
}

async function cacheAppShell() {
  const cache = await caches.open(CACHE_NAME)
  const urls = new Set(APP_SHELL)
  const seen = new Set()
  const queue = [...APP_SHELL]
  try {
    const response = await fetch(shellURL('./index.html'), { cache: 'reload' })
    if (response.ok) {
      const html = await response.text()
      discoverAppAssets(html).forEach(url => {
        urls.add(url)
        queue.push(url)
      })
      await cache.put(shellURL('./index.html'), new Response(html, {
        status: response.status,
        statusText: response.statusText,
        headers: response.headers,
      }))
    }
  } catch {
    // Shell HTML is best-effort during install.
  }
  while (queue.length) {
    const url = queue.shift()
    if (!url || seen.has(url)) continue
    seen.add(url)
    try {
      const response = await fetch(url, { cache: 'reload' })
      const contentType = response.headers.get('content-type') || ''
      const expectedCSS = url.endsWith('.css')
      const expectedJS = url.endsWith('.js')
      if (response.ok && (!expectedCSS || contentType.includes('text/css'))) {
        await cache.put(url, response.clone())
        if (expectedJS) {
          const js = await response.text()
          discoverDynamicImports(js, url).forEach(nextUrl => {
            if (!seen.has(nextUrl)) queue.push(nextUrl)
          })
        }
      }
    } catch {
      await Promise.resolve()
    }
  }
}

self.addEventListener('install', event => {
  event.waitUntil(cacheAppShell().then(() => self.skipWaiting()))
})

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

self.addEventListener('fetch', event => {
  const request = event.request
  if (request.method !== 'GET') return

  const url = new URL(request.url)
  if (url.origin !== self.location.origin) return
  const relativePath = url.pathname.startsWith(BASE_PATH)
    ? url.pathname.slice(BASE_PATH.length - 1)
    : url.pathname
  if (relativePath.startsWith('/api/') || relativePath.startsWith('/scene-ws')) return

  event.respondWith(
    fetch(request)
      .then(response => {
        if (response.ok) {
          const copy = response.clone()
          caches.open(CACHE_NAME).then(cache => cache.put(request, copy)).catch(() => undefined)
        }
        return response
      })
      .catch(() => caches.match(request).then(cached => {
        if (cached) return cached
        if (request.mode === 'navigate') {
          return caches.match(shellURL('./')).then(shell => shell || caches.match(shellURL('./index.html')))
        }
        return new Response('Offline: this AR asset is not cached.', { status: 503, headers: { 'content-type': 'text/plain' } })
      }))
  )
})