/*
 * libmedia mp4 chpl box parser
 *
 * 版权所有 (C) 2024 赵高兴
 * Copyright (C) 2024 Gaoxing Zhao
 *
 * 此文件是 libmedia 的一部分
 * This file is part of libmedia.
 * 
 * libmedia 是自由软件；您可以根据 GNU Lesser General Public License（GNU LGPL）3.1
 * 或任何其更新的版本条款重新分发或修改它
 * libmedia is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3.1 of the License, or (at your option) any later version.
 * 
 * libmedia 希望能够为您提供帮助，但不提供任何明示或暗示的担保，包括但不限于适销性或特定用途的保证
 * 您应自行承担使用 libmedia 的风险，并且需要遵守 GNU Lesser General Public License 中的条款和条件。
 * libmedia is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 */

import type { Atom, IsobmffContext } from '../type'
import type { AVChapter } from '../../../AVFormatContext'

import { logger } from '@libmedia/common'
import { type IOReader } from '@libmedia/common/io'
import { NOPTS_VALUE_BIGINT, type AVStream } from '@libmedia/avutil'

export default async function read(ioReader: IOReader, stream: AVStream, atom: Atom, isobmffContext: IsobmffContext) {

  const now = ioReader.getPos()

  const version = await ioReader.readUint8()
  // flags
  await ioReader.skip(3)

  if (version) {
    await ioReader.skip(4)
  }

  const count = await ioReader.readUint8()
  if (count) {
    const chapters: AVChapter[] = []
    for (let i = 0; i < count; i++) {
      const start = await ioReader.readInt64()
      const len = await ioReader.readUint8()
      const chapter: AVChapter = {
        id: BigInt(i),
        timeBase: {
          num: 1,
          den: 10000000
        },
        start,
        end: NOPTS_VALUE_BIGINT,
        metadata: {}
      }
      if (len) {
        chapter.metadata.title = await ioReader.readString(len)
      }
      chapters.push(chapter)
    }
    isobmffContext.chapters = chapters
  }

  const remainingLength = atom.size - Number(ioReader.getPos() - now)
  if (remainingLength > 0) {
    await ioReader.skip(remainingLength)
  }
  else if (remainingLength < 0) {
    logger.error(`read vpcc error, size: ${atom.size}, read: ${atom.size - remainingLength}`)
  }
}