#! /usr/bin/env python3

"Replace tabs with spaces in argument files. Print names of changed files."

import os
import sys
import getopt
import tokenize

def main():
 tabsize = 8
 try:
 opts, args = getopt.getopt(sys.argv[1:], "t:")
 if not args:
 raise getopt.error("At least one file argument required")
 except getopt.error as msg:
 print(msg)
 print("usage:", sys.argv[0], "[-t tabwidth] file ...")
 return
 for optname, optvalue in opts:
 if optname == '-t':
 tabsize = int(optvalue)

 for filename in args:
 process(filename, tabsize)


def process(filename, tabsize, verbose=True):
 try:
 with tokenize.open(filename) as f:
 text = f.read()
 encoding = f.encoding
 except IOError as msg:
 print("%r: I/O error: %s" % (filename, msg))
 return
 newtext = text.expandtabs(tabsize)
 if newtext == text:
 return
 backup = filename + "~"
 try:
 os.unlink(backup)
 except OSError:
 pass
 try:
 os.rename(filename, backup)
 except OSError:
 pass
 with open(filename, "w", encoding=encoding) as f:
 f.write(newtext)
 if verbose:
 print(filename)


if __name__ == '__main__':
 main()