import sequtils

type
  Header* = object
    name*: array[0..100, char]
    mode*: array[0..8, char]
    uid*: array[0..8, char]
    gid*: array[0..8, char]
    size*: array[0..12, char]
    mktime*: array[0..12, char]
    chksum*: array[0..8, char]
    typeflag*: char
    linkname*: array[0..100, char]
    magic*: array[0..6, char]
    version*: array[0..2, char]
    uname*: array[0..32, char]
    gname*: array[0..32, char]
    devmajor*: array[0..8, char]
    devminor*: array[0..8, char]
    prefix*: array[0..155, char]
    gnu_longname*: ref char
    gnu_longlink*: ref char

  ArchiveFile* = object
    header*: Header
    pos*: uint64
    size*: uint64

  Archive* = object
    file: File
    files*: seq[ArchiveFile]
    position: uint64

  ArchiveException = object of Exception


proc newTarArchive*(f: File): Archive =
  result = Archive(
    file: f
  )

proc newHeader*(): Header =
  result = Header()


proc parseBufferToHeader*(buffer: var array[0..512, char]): Header =
  result = newHeader()
  #result.name = buffer[0..100]
  result.name = buffer[0..100]

proc readArchiveFile*(a: Archive): ArchiveFile =
  var buffer: array[0..512, char]

  let readCount: int = readChars(a.file, buffer, a.position, 512)
  if readCount != 512:
    raise newException(ArchiveException, "Could not read 512 bytes")

  let header = buffer.parseBufferToHeader()
  result = ArchiveFile(
    header: header)