// Minimal service worker: only exists to catch the POST /share-target
// request from Android's share sheet (required for Web Share Target to
// work — the browser needs an installed SW controlling the scope). Stores
// the shared files in a temporary Cache entry, then redirects to a page
// that reads them and feeds them into the send flow.

const SHARE_CACHE = 'flit-share-v1'

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

self.addEventListener('activate', (event) => {
  event.waitUntil(self.clients.claim())
})

self.addEventListener('fetch', (event) => {
  const url = new URL(event.request.url)
  if (event.request.method === 'POST' && url.pathname === '/share-target') {
    event.respondWith(handleShareTarget(event))
  }
})

async function handleShareTarget(event) {
  const formData = await event.request.formData()
  const files = formData.getAll('files')
  const cache = await caches.open(SHARE_CACHE)
  await cache.put('/shared-files', new Response(await packFiles(files)))
  return Response.redirect('/?shared=1', 303)
}

async function packFiles(files) {
  // Pack as a multipart-ish JSON manifest + blobs isn't trivial inside a SW;
  // simplest robust approach: store each file as its own cache entry keyed
  // by index, plus a manifest of names/types.
  const cache = await caches.open(SHARE_CACHE)
  const manifest = []
  for (let i = 0; i < files.length; i++) {
    const f = files[i]
    manifest.push({ name: f.name, type: f.type, size: f.size, key: `/shared-file-${i}` })
    await cache.put(`/shared-file-${i}`, new Response(f))
  }
  return JSON.stringify(manifest)
}