#!/usr/bin/env python3
# vim: set noet sw=4 ts=4:

import subprocess
import sys

def main():
	delete = len(sys.argv) == 2 and sys.argv[1] == '-d'

	remotes = all_remotes()

	to_delete = []
	print('will delete:')
	for local, remote in iter_locals():
		if remote not in remotes:
			to_delete.append(local)
			sys.stdout.buffer.write(b'\t' + local)
	print()

	if delete and len(to_delete) > 0:
		subprocess.run([b'git', b'branch', b'-D'] + to_delete, check=True)

def all_remotes():
	refs = subprocess.run(['git', 'for-each-ref', '--format=%(refname:short)', 'refs/remotes'],
			capture_output=True, check=True)
	return frozenset(refs.stdout.rstrip(b'\n').split(b'\n'))

def iter_locals():
	refs = subprocess.run(['git', 'for-each-ref', '--format=%(refname:short) %(upstream)', 'refs/heads'],
			capture_output=True, check=True)
	for line in refs.stdout.split(b'\n'):
		if not line:
			continue
		local, remote = line.split(b' ', 1)
		if not remote:
			continue
		assert remote.startswith(b'refs/remotes/')
		remote = remote.removeprefix(b'refs/remotes/')
		yield local, remote

if __name__ == '__main__':
	main()