const sampleRate = 16000
export const soundCheckWav = Buffer.alloc(44 + sampleRate * 2)
soundCheckWav.write('RIFF', 0)
soundCheckWav.writeUInt32LE(soundCheckWav.length - 8, 4)
soundCheckWav.write('WAVEfmt ', 8)
soundCheckWav.writeUInt32LE(16, 16)
soundCheckWav.writeUInt16LE(1, 20)
soundCheckWav.writeUInt16LE(1, 22)
soundCheckWav.writeUInt32LE(sampleRate, 24)
soundCheckWav.writeUInt32LE(sampleRate * 2, 28)
soundCheckWav.writeUInt16LE(2, 32)
soundCheckWav.writeUInt16LE(16, 34)
soundCheckWav.write('data', 36)
soundCheckWav.writeUInt32LE(sampleRate * 2, 40)
for (let sample = 0; sample < sampleRate; sample++) {
  const time = sample / sampleRate
  const start = time < 0.5 ? 0.05 : 0.55
  const elapsed = time - start
  if (elapsed < 0 || elapsed >= 0.4) continue
  const envelope = Math.min(1, elapsed / 0.02, (0.4 - elapsed) / 0.02)
  const frequency = time < 0.5 ? 440 : 660
  soundCheckWav.writeInt16LE(Math.round(6553 * envelope * Math.sin(2 * Math.PI * frequency * elapsed)), 44 + sample * 2)
}

// Runs in the audio devices renderer; keep this function independent of module imports.
export function playSoundCheck(): Promise<void> {
  const media = document.querySelector('audio')
  if (!media) return Promise.reject(new Error('Проверка звука недоступна'))
  return new Promise<void>((resolve, reject) => {
    let finished = false
    const finish = (error?: Error) => {
      if (finished) return
      finished = true
      clearTimeout(timeout)
      media.removeEventListener('ended', ended)
      media.removeEventListener('error', failed)
      media.pause()
      media.removeAttribute('src')
      media.load()
      if (error) reject(error)
      else resolve()
    }
    const ended = () => finish()
    const failed = () => finish(new Error('Не удалось воспроизвести проверочный сигнал'))
    const timeout = setTimeout(() => finish(new Error('Превышено время проверки звука')), 3000)
    media.addEventListener('ended', ended)
    media.addEventListener('error', failed)
    media.muted = false
    media.volume = 1
    media.src = 'screen-app://app/sound-check.wav'
    void media.play().catch(failed)
  })
}