import MP4Box, { MP4File, MP4VideoTrack } from './mp4boxjs/mp4box.adapter.js'

export function getVideoInfo(file: File): Promise<MP4VideoTrack> {
  return new Promise((resolve) => {
    const mp4file = MP4Box.createFile()
    mp4file.onReady = (info) => {
      const track = info.videoTracks[0]
      resolve(track)
    }
    const fileSink = new MP4FileSink(mp4file)
    //@ts-ignore
    file.stream().pipeTo(new WritableStream(fileSink, { highWaterMark: 1 }))
  })
}

export class MP4FileSink {
  #file: MP4File
  #offset = 0

  constructor(file: MP4File) {
    this.#file = file
  }

  write(chunk: ArrayBuffer) {
    const buffer = new ArrayBuffer(chunk.byteLength)
    //@ts-ignore
    new Uint8Array(buffer).set(chunk)
    //@ts-ignore
    buffer.fileStart = this.#offset
    this.#offset += buffer.byteLength
    //@ts-ignore
    this.#file!.appendBuffer(buffer)
  }

  close() {
    this.#file.flush()
  }
}