Quick python script to rename files in a diretory, has allow/deny functionality and renaming based on regular expressions

renamer.py

#!/usr/bin/env python

import os
import re
import sys

def generate_new_name(filename):
  """
  Generates a new name for a file by removing a pattern matching the regular
  expression ' \[A-Za-z0-9\]+ - handbroken.*', cleaning up symbols,
  and keeping the original extension.
  """
  name, ext = os.path.splitext(filename)
  # Remove the main pattern
  new_name = re.sub(r" \[[A-Za-z0-9]+\] - handbroken.*", "", name)
  
  # Replace underscores and dashes with a space
  new_name = new_name.replace('_', ' ').replace('-', ' ')
  
  # Remove any character that is not a letter, number, space, or apostrophe
  new_name = re.sub(r"[^a-zA-Z0-9\s']", '', new_name)
  
  # Replace multiple spaces with a single space and trim whitespace
  new_name = re.sub(r'\s+', ' ', new_name).strip()
  
  # Capitalize the new name
  new_name = new_name.capitalize()
  
  return new_name + ext

def rename_files():
  """
  Traverses all files in the current directory and renames them based on
  a configurable allow/deny filter system.
  """
  # --- Configuration ---
  # Set the filtering order: "allow-then-deny" or "deny-then-allow"
  filter_order = "allow-then-deny"

  # Files matching these patterns will be considered for processing.
  # If filter_order is "allow-then-deny" and this list is empty, all files are initially allowed.
  allow_patterns = [r".*"]

  # Files matching these patterns will be excluded from processing.
  deny_patterns = [
      r".*\.py",      # Deny all Python files
      r"\.DS_Store",  # Deny macOS metadata files
  ]
  # --- End Configuration ---

  # --- Validate Configuration ---
  if filter_order not in ["allow-then-deny", "deny-then-allow"]:
    raise ValueError(f"Invalid filter_order: '{filter_order}'. Must be 'allow-then-deny' or 'deny-then-allow'.")
  # --- End Validation ---

  for filename in os.listdir('.'):
    if not os.path.isfile(filename):
      continue

    # --- Filtering Logic ---
    is_allowed = any(re.fullmatch(p, filename) for p in allow_patterns)
    is_denied = any(re.fullmatch(p, filename) for p in deny_patterns)

    should_process = False
    if filter_order == "allow-then-deny":
      # Process if it's in the allow list (or if the list is empty) AND it's not in the deny list.
      should_process = (not allow_patterns or is_allowed) and not is_denied
    elif filter_order == "deny-then-allow":
      # Process if it's NOT in the deny list, OR if it's explicitly in the allow list (as an exception).
      should_process = not is_denied or is_allowed
    
    if not should_process:
      continue
    # --- End Filtering Logic ---

    new_name = generate_new_name(filename)
    if new_name != filename:
      print(f"Renaming:\n\t'{filename}'\n\t'{new_name}'")
      if "-x" in sys.argv:
        os.rename(filename, new_name)

if __name__ == "__main__":
  args = sys.argv[1:]
  is_dry_run = not (len(args) == 1 and args[0] == '-x')

  if not (len(args) == 0 or is_dry_run is False):
    print("Error: Invalid arguments. Use no arguments for a dry run, or '-x' to execute renaming.", file=sys.stderr)
    sys.exit(1)

  if is_dry_run:
    print("--- DRY RUN: NO FILES WILL BE RENAMED ---")

  rename_files()

  if is_dry_run:
    print("--- END OF DRY RUN ---")