/*
 * libmedia guess dts from pts
 *
 * 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.
 *
 */
export default function guessDtsFromPts(delay: int32, ptsList: int64[]) {
  if (ptsList.length < delay) {
    return ptsList.slice().sort((a, b) => {
      if (a > b) {
        return 1
      }
      else {
        return -1
      }
    })
  }
  const pre: int64[] = []
  const dtsList = ptsList.slice().sort((a, b) => {
    if (a > b) {
      return 1
    }
    else {
      return -1
    }
  })
  if (delay) {
    const defaultDuration = dtsList[dtsList.length - 1] - dtsList[dtsList.length - 2]
    for (let i = delay; i > 0; i-- ) {
      pre.push((pre.length ? pre[pre.length - 1] : 0n) + (i >= dtsList.length ? defaultDuration : (dtsList[i] - dtsList[i - 1])))
    }
    pre.reverse()
  }

  const result: int64[] = []
  for (let i = 0; i < delay; i++) {
    result.push(dtsList[0] - pre[i])
  }
  return result.concat(dtsList)
}