Convert the files in a directory from space-indented to tab indented detecting the indentation level automatically

tabber.py

''' TABBER: Because spaces suck

This script will recursively convert all files in its directory from space indented to tab indented.
It will detect the number of spaces used for indentation and transform them into tabbed files.

Usage:
	1. Copy the directory you want to convert and put this file inside. If you're brave enough, skip the
		copying part.
	2. Review the EXTENSIONS and IGNORE_FILES values.
	3. Run it.
	4. Review the errors if any, and run it again.
'''

from math import gcd
from os import listdir
from os.path import isdir, join
from re import findall, match

EXTENSIONS = 'txt', 'json', 'js', 'yaml', 'vue', 'editorconfig', 'md', 'gitignore'
IGNORE_FILES = 'node_modules', '.vscode', '.git', 'package-lock.json'

def tabulate(base='.'):
	for file in listdir(base):
		if file in IGNORE_FILES: continue
		path = join(base, file)
		if isdir(path):
			tabulate(path)
		elif any(path.endswith(ext) for ext in EXTENSIONS):
			with open(path, 'r', encoding='utf-8') as fp:
				content = fp.read()
			space_starts = findall(r'\n( +)[^\s]', content)
			tab_starts = findall(r'\n(\t+)[^\s]', content)
			if len(space_starts) and len(tab_starts):
				print('%s\n\tSkipped due to mixed spaces and tabs' % path)
				continue
			if not len(space_starts): continue
			space_starts = list({len(s) for s in space_starts if s is not None})
			tab_size = space_starts[0]
			for length in space_starts[1:]:
				tab_size = gcd(length, tab_size)
			if tab_size == 1:
				print('%s\n\tSkipped due to inconsistent spacing of lengths: %s' % (path, ', '.join(sorted(space_starts))))
			res = ''
			previous_indentation = -1
			for n, line in enumerate(content.split('\n')):
				if not len(line):
					res += '\n'
					continue
				indentation = match(r'^ +', line)
				indentation = len(indentation.group()) // tab_size if indentation is not None else 0
				if abs(previous_indentation - indentation) > 1:
					print('%s\n\tSkipped due to inconsistent line indentation on line %d' % (path, n))
					break
				res += indentation * '\t' + line.lstrip(' ') + '\n'
				previous_indentation = indentation
			else:
				with open(path, 'w', encoding='utf-8') as fp:
					fp.write(res.rstrip())

if __name__ == '__main__':
	tabulate()