diff.py

#!/usr/bin/python3
import filecmp
import os
import shutil
from sys import argv


def check_valid_dir(directory):
    return os.path.exists(directory) and os.path.isdir(directory)


def copy_files_to(files, src, dest):
    for current in files:
        dir_name = os.path.join(dest, os.path.dirname(current))
        if not os.path.exists(dir_name):
            os.makedirs(dir_name)
        shutil.copy(os.path.join(src, current), os.path.join(dest, current))


if len(argv) != 4:
    print("Invalid number of parameters")
    print("Usage:")
    print(argv[0], "<old_src> <new_src> <dest_dir>")
    exit(1)

_, old, new, dst = argv

if not check_valid_dir(old) or not check_valid_dir(new) or not check_valid_dir(dst):
    print(f'All parameters must exist and be directories')
    exit(1)

new_files = []
old_files = []

to_delete = []
to_replace_files = []
to_add_files = []

for dirname, dirnames, filenames in os.walk(old):
    path = os.path.relpath(dirname, old)
    for old_filename in filenames:
        old_files.append(os.path.join(path, old_filename))

for dirname, dirnames, filenames in os.walk(new):
    path = os.path.relpath(dirname, new)
    for new_filename in filenames:
        new_files.append(os.path.join(path, new_filename))

for old_file in old_files:
    if old_file not in new_files:
        to_delete.append(old_file)

for new_file in new_files:
    if new_file not in old_files:
        to_add_files.append(new_file)

for to_delete_file in to_delete:
    old_files.remove(to_delete_file)

for found_file in old_files:
    file_old = os.path.join(old, found_file)
    file_new = os.path.join(new, found_file)
    equals = filecmp.cmp(file_old, file_new, False)
    if not equals:
        to_replace_files.append(found_file)

copy_files_to(to_replace_files, new, dst)
copy_files_to(to_add_files, new, dst)

if len(to_delete) > 0:
    to_delete_file = os.path.join(dst, "to_delete.txt")
    f_delete = open(to_delete_file, "w")
    for dfile in to_delete:
        f_delete.write(dfile + "\n")
    f_delete.close()
    print(f"Files to be deleted were listed in {to_delete_file}")

print("Done")