#!/usr/bin/env python3
"""Step 0 of every rtl-ip-replace run (MANDATORY, user directive 2026-07-23):
move ALL existing content of the fixed output dir into backup_<timestamp>/,
so the run always generates everything fresh while keeping full history.

Usage: python backup_outdir.py <outdir>
Existing backup_* subdirectories are kept in place (not re-nested).
"""
import os, shutil, sys, time

def main():
    if len(sys.argv) != 2:
        sys.exit('usage: backup_outdir.py <outdir>')
    d = os.path.abspath(sys.argv[1])
    os.makedirs(d, exist_ok=True)
    items = [x for x in os.listdir(d) if not x.startswith('backup_')]
    if not items:
        print('nothing to back up in', d)
        return
    bdir = os.path.join(d, 'backup_' + time.strftime('%Y%m%d_%H%M%S'))
    os.makedirs(bdir)
    for x in items:
        shutil.move(os.path.join(d, x), os.path.join(bdir, x))
    print(f'backed up {len(items)} item(s) -> {bdir}')

if __name__ == '__main__':
    main()