#!/usr/bin/env python3

# Based heavily on
# https://github.com/gssapi/mod_auth_gssapi/blob/master/contrib/sweeper.py

# Copyright (C) 2016 mod_auth_gssapi contributors - See COPYING for (C) terms

# If one uses both sessions and unique ccache names, then the filesystem will
# become littered with ccache files unless the accessed application cleans
# them up itself.  This script will minimize ccache file proliferation by
# removing any ccaches that have expired from the filesystem, and serves as an
# example of how this cleaning can be performed.

import argparse
import os
import stat
import sys
import time

from gssapi.raw import acquire_cred_from
from ipaplatform.paths import paths


# process file as a ccache and indicate whether it is expired
def should_delete(fname, t, minlife):
    try:
        # skip directories and other non-files
        st = os.stat(fname)
        if not stat.S_ISREG(st.st_mode):
            return False

        # ignore files that are newer than minlife minutes
        if t - st.st_mtime < minlife * 60:
            return False

        creds = acquire_cred_from({b"ccache": fname.encode("UTF-8")})
    except FileNotFoundError:
        # someone else did the work for us
        return False
    except Exception as e:
        print("Not deleting %s due to error %s" % (fname, e))
        return False

    return creds.lifetime == 0


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Sweep expired ccaches")
    parser.add_argument("-m", dest="minlife", type=int,
                        help="ignore newer files than this (default: 30)",
                        default=30)
    args = parser.parse_args()

    os.environ["GSS_USE_PROXY"] = "yes"
    os.environ["GSSPROXY_BEHAVIOR"] = "REMOTE_FIRST"

    print("Running sweeper...")

    t = time.time()

    os.chdir(paths.IPA_CCACHES)
    for fname in os.listdir(paths.IPA_CCACHES):
        if should_delete(fname, t, args.minlife):
            os.unlink(fname)

    print("Sweeper finished successfully!")
    sys.exit(0)