#!/usr/bin/env python3
import argparse
import os
import subprocess
import sys

from typing import Set

ZULIP_PATH = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.append(ZULIP_PATH)
from scripts.lib.zulip_tools import DEPLOYMENTS_DIR, get_recent_deployments, \
    may_be_perform_purging

def parse_args():
    # type: () -> argparse.Namespace
    parser = argparse.ArgumentParser(
        description="This script can be used for cleaning old unused deployments.",
        epilog="Orphaned/unused caches older than threshold days will be automatically "
        "examined and removed.")
    parser.add_argument(
        "--threshold", dest="threshold_days", type=int, default=14,
        nargs="?", metavar="<days>", help="Deployments older than "
        "threshold days will be deleted. (defaults to 14)")
    parser.add_argument(
        "--dry-run", dest="dry_run", action="store_true",
        help="If specified then script will only print the deployments and "
        "caches that it will delete/keep back. It will not delete anything.")
    parser.add_argument(
        "--verbose", dest="verbose", action="store_true",
        help="If specified then script will print a detailed report "
        "of what is going on.")

    args = parser.parse_args()
    args.verbose |= args.dry_run    # Always print a detailed report in case of dry run.
    return args

def get_deployments_to_be_purged(recent_deployments):
    # type: (Set[str]) -> Set[str]
    all_deployments = set([os.path.join(DEPLOYMENTS_DIR, deployment)
                           for deployment in os.listdir(DEPLOYMENTS_DIR)])
    deployments_to_purge = set()
    for deployment in all_deployments:
        # Deployments whose name is not in the format of a timestamp are
        # always included in the recent_deployments and are not deleted.
        if not os.path.isdir(deployment):
            # Skip things like uwsgi sockets.
            continue
        if not os.path.exists(os.path.join(deployment, "zerver")):
            # Skip things like "lock" that aren't actually a deployment directory
            continue
        if deployment not in recent_deployments:
            deployments_to_purge.add(deployment)
    return deployments_to_purge

def main():
    # type: () -> None
    args = parse_args()
    deployments_to_keep = get_recent_deployments(args.threshold_days)
    deployments_to_purge = get_deployments_to_be_purged(deployments_to_keep)

    may_be_perform_purging(
        deployments_to_purge, deployments_to_keep, "deployment", args.dry_run, args.verbose)

    if not args.dry_run:
        print("Deployments cleaned successfully...")
        print("Cleaning orphaned/unused caches...")

    # Call 'clean-unused-caches' script to clean any orphaned/unused caches.
    subprocess.check_call([os.path.join(ZULIP_PATH, "scripts/lib/clean-unused-caches")] + sys.argv[1:])
    print("Done!")

if __name__ == "__main__":
    main()