# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
#
# SPDX-License-Identifier: MPL-2.0
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0.  If a copy of the MPL was not distributed with this
# file, you can obtain one at https://mozilla.org/MPL/2.0/.
#
# See the COPYRIGHT file distributed with this work for additional
# information regarding copyright ownership.

from __future__ import print_function
import os, sys, argparse, glob, re, time, calendar, pprint
from collections import defaultdict

prog = "dnssec-keymgr"

from isc import dnskey, keydict, keyseries, policy, parsetab, utils


############################################################################
# print a fatal error and exit
############################################################################
def fatal(*args, **kwargs):
    print(*args, **kwargs)
    sys.exit(1)


############################################################################
# find the location of an external command
############################################################################
def set_path(command, default=None):
    """find the location of a specified command. If a default is supplied,
    exists and it's an executable, we use it; otherwise we search PATH
    for an alternative.
    :param command: command to look for
    :param default: default value to use
    :return: PATH with the location of a suitable binary
    """
    fpath = default
    if not fpath or not os.path.isfile(fpath) or not os.access(fpath, os.X_OK):
        path = os.environ["PATH"]
        if not path:
            path = os.path.defpath
        for directory in path.split(os.pathsep):
            fpath = directory + os.sep + command
            if os.path.isfile(fpath) and os.access(fpath, os.X_OK):
                break
            fpath = None

    return fpath


############################################################################
# parse arguments
############################################################################
def parse_args():
    """Read command line arguments, returns 'args' object
    :return: args object properly prepared
    """

    keygen = set_path(
        "dnssec-keygen", os.path.join(utils.prefix("sbin"), "dnssec-keygen")
    )
    settime = set_path(
        "dnssec-settime", os.path.join(utils.prefix("sbin"), "dnssec-settime")
    )

    parser = argparse.ArgumentParser(
        description=prog + ": schedule "
        "DNSSEC key rollovers according to a "
        "pre-defined policy"
    )

    parser.add_argument(
        "zone",
        type=str,
        nargs="*",
        default=None,
        help="Zone(s) to which the policy should be applied "
        + "(default: all zones in the directory)",
    )
    parser.add_argument(
        "-K", dest="path", type=str, help="Directory containing keys", metavar="dir"
    )
    parser.add_argument(
        "-c", dest="policyfile", type=str, help="Policy definition file", metavar="file"
    )
    parser.add_argument(
        "-g",
        dest="keygen",
        default=keygen,
        type=str,
        help="Path to 'dnssec-keygen'",
        metavar="path",
    )
    parser.add_argument(
        "-r",
        dest="randomdev",
        type=str,
        default=None,
        help="DEPRECATED",
        metavar="path",
    )
    parser.add_argument(
        "-s",
        dest="settime",
        default=settime,
        type=str,
        help="Path to 'dnssec-settime'",
        metavar="path",
    )
    parser.add_argument(
        "-k",
        dest="no_zsk",
        action="store_true",
        default=False,
        help="Only apply policy to key-signing keys (KSKs)",
    )
    parser.add_argument(
        "-z",
        dest="no_ksk",
        action="store_true",
        default=False,
        help="Only apply policy to zone-signing keys (ZSKs)",
    )
    parser.add_argument(
        "-f",
        "--force",
        dest="force",
        action="store_true",
        default=False,
        help="Force updates to key events " + "even if they are in the past",
    )
    parser.add_argument(
        "-q",
        "--quiet",
        dest="quiet",
        action="store_true",
        default=False,
        help="Update keys silently",
    )
    parser.add_argument("-v", "--version", action="version", version=utils.version)

    args = parser.parse_args()

    if args.randomdev:
        fatal("ERROR: -r option has been deprecated.")

    if args.no_zsk and args.no_ksk:
        fatal("ERROR: -z and -k cannot be used together.")

    if args.keygen is None:
        fatal("ERROR: dnssec-keygen not found")

    if args.settime is None:
        fatal("ERROR: dnssec-settime not found")

    # if a policy file was specified, check that it exists.
    # if not, use the default file, unless it doesn't exist
    if args.policyfile is not None:
        if not os.path.exists(args.policyfile):
            fatal('ERROR: Policy file "%s" not found' % args.policyfile)
    else:
        args.policyfile = os.path.join(utils.sysconfdir, "dnssec-policy.conf")
        if not os.path.exists(args.policyfile):
            args.policyfile = None

    return args


############################################################################
# main
############################################################################
def main():
    args = parse_args()

    # As we may have specific locations for the binaries, we put that info
    # into a context object that can be passed around
    context = {
        "keygen_path": args.keygen,
        "settime_path": args.settime,
        "keys_path": args.path,
        "randomdev": args.randomdev,
    }

    try:
        dp = policy.dnssec_policy(args.policyfile)
    except Exception as e:
        fatal("Unable to load DNSSEC policy: " + str(e))

    try:
        kd = keydict(dp, path=args.path, zones=args.zone)
    except Exception as e:
        fatal("Unable to build key dictionary: " + str(e))

    try:
        ks = keyseries(kd, context=context)
    except Exception as e:
        fatal("Unable to build key series: " + str(e))

    try:
        ks.enforce_policy(
            dp, ksk=args.no_zsk, zsk=args.no_ksk, force=args.force, quiet=args.quiet
        )
    except Exception as e:
        fatal("Unable to apply policy: " + str(e))