/** Video-only PiP adapter. The existing element/stream remains app-owned.
 * No URLs, credentials, tracks or keys cross the dashboard message boundary. */
export function attachVideoPip({ button, status, getVideo, dashboardOrigin, win = window, doc = document }) {
  const origin = new URL(dashboardOrigin).origin
  let session = null, native = false, selected = null, busy = false, timer = null
  let reserved = false, reserving = false
  let acquisition = null
  let pendingEntry = false, pendingExit = false, exitVideo = null, disposed = false
  let failedExit = null
  let leaveListener = null, fullscreenListener = null, terminalListener = null
  const say = message => { status.textContent = message }
  const send = (action, values = {}, owner = { session, acquisition }) => {
    if (owner.session) win.parent.postMessage({ type: 'archipelago:video-request', version: 1, ...owner, action, ...values }, origin)
  }
  function finish() {
    clearTimeout(timer); timer = null; busy = false; button.disabled = !disposed && pendingExit
  }
  function clear() {
    finish()
    selected?.removeEventListener('play', publish)
    selected?.removeEventListener('pause', publish)
    selected?.removeEventListener('ended', terminalListener)
    selected?.removeEventListener('error', terminalListener)
    selected?.removeEventListener('enterpictureinpicture', leaveListener)
    selected?.removeEventListener('leavepictureinpicture', leaveListener)
    if (fullscreenListener) doc.removeEventListener('fullscreenchange', fullscreenListener)
    leaveListener = null; fullscreenListener = null; terminalListener = null; selected = null
  }
  function publish() { if (selected) send('state', { playing: !selected.paused && !selected.ended }) }
  function leave() {
    clear()
    if (!pendingExit) say('Returned to the call. Picture-in-picture does not end the call.')
  }
  async function exitOwned(video) {
    if (!video || pendingExit) return
    const exits = [['pictureInPictureElement', 'exitPictureInPicture'], ['fullscreenElement', 'exitFullscreen']]
      .filter(([field]) => doc[field] === video)
    if (!exits.length) return
    pendingExit = true; exitVideo = video
    if (!disposed) { button.disabled = true; say('Leaving picture-in-picture. Your call remains connected.') }
    // Document-global exits must settle before any new presentation request.
    // Do not queue a future entry: fullscreen still needs a fresh user gesture.
    const results = await Promise.allSettled(exits.map(async ([, method]) => {
      if (typeof doc[method] !== 'function') throw Error('Presentation exit unavailable')
      await doc[method]()
    }))
    pendingExit = false
    const stillOwned = doc.pictureInPictureElement === video || doc.fullscreenElement === video
    failedExit = results.some(result => result.status === 'rejected') || stillOwned ? video : null
    exitVideo = !disposed && stillOwned ? video : null
    if (!disposed) {
      button.disabled = busy
      say(stillOwned ? 'Could not exit picture-in-picture. Use the browser controls or click to retry exiting. Your call remains connected.'
        : 'Return to the call. Choose a video to open picture-in-picture.')
    }
  }
  function stop() {
    const video = selected || exitVideo
    const owner = { session, acquisition }
    const release = Boolean(selected || reserved || reserving)
    reserved = false; reserving = false; acquisition = null
    // Detach before invoking browser APIs, which can emit departure inline.
    clear()
    void exitOwned(video).then(() => {
      if (release && !pendingEntry && !pendingExit && (!video || (failedExit !== video && doc.fullscreenElement !== video && doc.pictureInPictureElement !== video))) {
        send('release', { presentationSettled: true }, owner)
      }
    })
    if (!disposed && !pendingExit) say('Return to the call. Choose a video to open picture-in-picture.')
  }
  function message(event) {
    if (event.source !== win.parent || event.origin !== origin) return
    const data = event.data
    if (data?.type !== 'archipelago:video-state' || data.version !== 1) return
    if (data.state === 'connected' && typeof data.session === 'string' && /^[a-f0-9-]{36}$/.test(data.session)) {
      if (session && session !== data.session) stop()
      session = data.session; native = data.native === true; return
    }
    if (!session || data.session !== session) return
    if (data.acquisition !== acquisition) return
    if (data.state === 'reserved' && reserving) {
      reserving = false; reserved = true; finish()
      say('Ready. Click picture-in-picture again to fullscreen the video.')
      return
    }
    if (!selected && !reserved && !reserving) return
    if (data.state === 'entered') { finish(); say('Picture-in-picture is active. Your call remains connected.') }
    if (data.state === 'error') { stop(); say(typeof data.message === 'string' ? data.message.slice(0, 300) : 'Picture-in-picture failed.') }
    if (data.state === 'closed' || data.state === 'restored' || data.state === 'released') {
      stop()
    }
    if (data.state === 'command' && selected) {
      if (data.command === 'pause') selected.pause()
      if (data.command === 'play') void selected.play().catch(() => say('Return to the call to resume video.'))
    }
  }
  async function enter() {
    if (disposed || busy || pendingEntry || pendingExit) return
    if (exitVideo) {
      if (doc.pictureInPictureElement === exitVideo || doc.fullscreenElement === exitVideo) {
        void exitOwned(exitVideo); return
      }
      exitVideo = null
    }
    if (selected) { stop(); return }
    const video = getVideo()
    if (!video || !video.videoWidth || !video.videoHeight || video.ended) { say('Wait for a call video before opening picture-in-picture.'); return }
    if (native && session && !(doc.pictureInPictureEnabled && typeof video.requestPictureInPicture === 'function') && !reserved) {
      acquisition = crypto.randomUUID()
      reserving = true; busy = true; button.disabled = true
      send('reserve')
      timer = setTimeout(() => { stop(); say('Picture-in-picture reservation was not confirmed.') }, 12000)
      return
    }
    if (!reserved) stop()
    selected = video
    for (const name of ['play', 'pause']) video.addEventListener(name, publish)
    const onTerminal = () => { if (terminalListener === onTerminal) stop() }
    terminalListener = onTerminal
    for (const name of ['ended', 'error']) video.addEventListener(name, onTerminal)
    let presented = false
    busy = true; button.disabled = true
    // Browser entry promises are not cancellable. Keep retries single-flight
    // until a cancelled request settles and its late-owned surface is released.
    pendingEntry = true
    const owner = { session, acquisition }
    try {
      if (doc.pictureInPictureEnabled && typeof video.requestPictureInPicture === 'function') {
        const onLeave = () => {
          if (leaveListener !== onLeave) return
          if (doc.pictureInPictureElement === video) presented = true
          else if (presented) stop()
        }
        leaveListener = onLeave
        video.addEventListener('enterpictureinpicture', onLeave)
        video.addEventListener('leavepictureinpicture', onLeave)
        await video.requestPictureInPicture()
        if (selected !== video) {
          await exitOwned(video)
          return
        }
        if (doc.pictureInPictureElement !== video) { stop(); return }
        presented = true
        say('Picture-in-picture is active. Your call remains connected.')
        finish()
      } else if (native && session && typeof video.requestFullscreen === 'function') {
        const onFullscreen = () => {
          if (fullscreenListener !== onFullscreen) return
          if (doc.fullscreenElement === video) presented = true
          else if (presented) stop()
        }
        fullscreenListener = onFullscreen
        doc.addEventListener('fullscreenchange', onFullscreen)
        // A second click supplies a fresh gesture after the host reservation.
        await video.requestFullscreen()
        if (selected !== video) {
          await exitOwned(video)
          return
        }
        if (doc.fullscreenElement !== video) { stop(); return }
        presented = true
        send('enter', { width: video.videoWidth, height: video.videoHeight, playing: !video.paused })
        timer = setTimeout(() => { stop(); say('Picture-in-picture was not confirmed. Return to the call and retry.') }, 12000)
      } else {
        stop(); say('Picture-in-picture is unavailable in this browser or Companion. The call remains here.')
      }
    } catch (error) {
      if (selected === video) {
        stop(); say(error instanceof Error ? error.message : 'Picture-in-picture could not start.')
      }
    } finally {
      pendingEntry = false
      if (selected !== video && !pendingExit && failedExit !== video && doc.fullscreenElement !== video && doc.pictureInPictureElement !== video) {
        send('release', { presentationSettled: true }, owner)
      }
    }
  }
  const ready = () => {
    if (win.parent !== win) win.parent.postMessage({ type: 'archipelago:video-ready', version: 1 }, origin)
  }
  win.addEventListener('message', message)
  win.addEventListener('pageshow', ready)
  win.addEventListener('pagehide', stop)
  button.addEventListener('click', enter)
  ready()
  return { enter, stop, dispose() {
    disposed = true
    stop(); win.removeEventListener('message', message); win.removeEventListener('pageshow', ready)
    win.removeEventListener('pagehide', stop); button.removeEventListener('click', enter)
  } }
}