import os, shutil

def flipchunk(iterable, inc):
  chunks = [iterable[x:x+inc] for x in range(0, len(iterable), inc)]
  c2 = [x[::-1] for x in chunks]
  return c2

def swap2bik(infile):
  with open(infile, "rb") as inf:
    data = inf.read()
  flipped  = flipchunk(data, 4)
  output = b"".join(flipped)
  fname = infile.replace("bikswap", "bik")
  with open(fname, "wb") as ouf:
    ouf.write(output)

def main(infolder):
  os.chdir(infolder)
  bikswaps = [x for x in os.listdir(os.getcwd()) if x.endswith(".bikswap")]
  for bikswap in bikswaps:
    swap2bik(bikswap)