#!/usr/bin/env python3
# SPDX-FileCopyrightText: 2023 Sotiris Papatheodorou
# SPDX-License-Identifier: BSD-2-Clause

"""
A script to migrate the offpunk cache to the newest version.

For each new version of offpunk that requires changes to the cache a migration
function should be written. The name of the function should have the format
v<major-version>_<minor-version>_<patch-version> and it should accept the
offpunk cache directory as a string. The function should perform a migration
from the immediately previous cache format. All migration functions must be
called at the end of this script from oldest to newest.
"""

import argparse
import os
import os.path


def v1_10_0(cache_dir: str) -> None:
    """
    Rename index.txt to gophermap in the Gopher protocol cache.
    """
    for root, _, files in os.walk(os.path.join(cache_dir, 'gopher')):
        for f in files:
            if f == 'index.txt':
                src = os.path.join(root, f)
                dst = os.path.join(root, 'gophermap')
                os.rename(src, dst)


if __name__ == '__main__':
    # Compute the default offpunk cache directory.
    xdg_cache_home = os.environ.get('XDG_CACHE_HOME')
    if xdg_cache_home:
        default_cache_dir = os.path.join(xdg_cache_home, 'offpunk')
    else:
        default_cache_dir = os.path.join(os.path.expanduser('~'), '.cache/offpunk')
    # Parse command line arguments.
    parser = argparse.ArgumentParser(
        description='Migrate the offpunk cache to a newer version.')
    parser.add_argument('cache_dir', metavar='CACHE_DIR', nargs='?',
        default=default_cache_dir, help='the path to the cache')
    args = parser.parse_args()
    # Run the cache migration functions from the oldest to the newest version.
    v1_10_0(args.cache_dir)