#!/usr/bin/env python3
#
# Compute our KCC topology
#
# Copyright (C) Dave Craft 2011
# Copyright (C) Andrew Bartlett 2015
#
# Andrew Bartlett's alleged work performed by his underlings Douglas
# Bagnall and Garming Sam.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import os
import sys
import random

# ensure we get messages out immediately, so they get in the samba logs,
# and don't get swallowed by a timeout
os.environ['PYTHONUNBUFFERED'] = '1'

# forcing GMT avoids a problem in some timezones with kerberos. Both MIT
# heimdal can get mutual authentication errors due to the 24 second difference
# between UTC and GMT when using some zone files (eg. the PDT zone from
# the US)
os.environ["TZ"] = "GMT"

# Find right directory when running from source tree
sys.path.insert(0, "bin/python")

import optparse
import time

from samba import getopt as options

from samba.kcc.graph_utils import verify_and_dot, list_verify_tests
from samba.kcc.graph_utils import GraphError

import logging
from samba.kcc.debug import logger, DEBUG, DEBUG_FN
from samba.kcc import KCC

# If DEFAULT_RNG_SEED is None, /dev/urandom or system time is used.
DEFAULT_RNG_SEED = None


def test_all_reps_from(kcc, dburl, lp, creds, unix_now, rng_seed=None,
                       ldif_file=None):
    """Run the KCC from all DSAs in read-only mode

    The behaviour depends on the global opts variable which contains
    command line variables. Usually you will want to run it with
    opt.dot_file_dir set (via --dot-file-dir) to see the graphs that
    would be created from each DC.

    :param lp: a loadparm object.
    :param creds: a Credentials object.
    :param unix_now: the unix epoch time as an integer
    :param rng_seed: a seed for the random number generator
    :return None:
    """
    # This implies readonly and attempt_live_connections
    dsas = kcc.list_dsas()
    samdb = kcc.samdb
    needed_parts = {}
    current_parts = {}

    guid_to_dnstr = {}
    for site in kcc.site_table.values():
        guid_to_dnstr.update((str(dsa.dsa_guid), dnstr)
                             for dnstr, dsa in site.dsa_table.items())

    dot_edges = []
    dot_vertices = []
    colours = []
    vertex_colours = []

    for dsa_dn in dsas:
        if rng_seed is not None:
            random.seed(rng_seed)
        kcc = KCC(unix_now, readonly=True,
                  verify=opts.verify, debug=opts.debug,
                  dot_file_dir=opts.dot_file_dir)
        if ldif_file is not None:
            try:
                # The dburl in this case is a temporary database.
                # Its non-existence is ensured at the script startup.
                # If it exists, it is from a previous iteration of
                # this loop -- unless we're in an unfortunate race.
                # Because this database is temporary, it lacks some
                # detail and needs to be re-created anew to set the
                # local dsa.
                os.unlink(dburl)
            except OSError:
                pass

            kcc.import_ldif(dburl, lp, ldif_file, dsa_dn)
        else:
            kcc.samdb = samdb
        kcc.run(dburl, lp, creds, forced_local_dsa=dsa_dn,
                forget_local_links=opts.forget_local_links,
                forget_intersite_links=opts.forget_intersite_links,
                attempt_live_connections=opts.attempt_live_connections)

        current, needed = kcc.my_dsa.get_rep_tables()

        for dsa in kcc.my_site.dsa_table.values():
            if dsa is kcc.my_dsa:
                continue
            kcc.translate_ntdsconn(dsa)
            c, n = dsa.get_rep_tables()
            current.update(c)
            needed.update(n)

        for name, rep_table, rep_parts in (
                ('needed', needed, needed_parts),
                ('current', current, current_parts)):
            for part, nc_rep in rep_table.items():
                edges = rep_parts.setdefault(part, [])
                for reps_from in nc_rep.rep_repsFrom:
                    source = guid_to_dnstr[str(reps_from.source_dsa_obj_guid)]
                    dest = guid_to_dnstr[str(nc_rep.rep_dsa_guid)]
                    edges.append((source, dest))

        for site in kcc.site_table.values():
            for dsa in site.dsa_table.values():
                if dsa.is_ro():
                    vertex_colours.append('#cc0000')
                else:
                    vertex_colours.append('#0000cc')
                dot_vertices.append(dsa.dsa_dnstr)
                if dsa.connect_table:
                    DEBUG_FN("DSA %s %s connections:\n%s" %
                             (dsa.dsa_dnstr, len(dsa.connect_table),
                              [x.from_dnstr for x in
                               dsa.connect_table.values()]))
                for con in dsa.connect_table.values():
                    if con.is_rodc_topology():
                        colours.append('red')
                    else:
                        colours.append('blue')
                    dot_edges.append((con.from_dnstr, dsa.dsa_dnstr))

    verify_and_dot('all-dsa-connections', dot_edges, vertices=dot_vertices,
                   label="all dsa NTDSConnections", properties=(),
                   debug=DEBUG, verify=opts.verify,
                   dot_file_dir=opts.dot_file_dir,
                   directed=True, edge_colors=colours,
                   vertex_colors=vertex_colours)

    for name, rep_parts in (('needed', needed_parts),
                            ('current', current_parts)):
        for part, edges in rep_parts.items():
            verify_and_dot('all-repsFrom_%s__%s' % (name, part), edges,
                           directed=True, label=part,
                           properties=(), debug=DEBUG, verify=opts.verify,
                           dot_file_dir=opts.dot_file_dir)

##################################################
# samba_kcc entry point
##################################################


parser = optparse.OptionParser("samba_kcc [options]")
sambaopts = options.SambaOptions(parser)
credopts = options.CredentialsOptions(parser)

parser.add_option_group(sambaopts)
parser.add_option_group(credopts)
parser.add_option_group(options.VersionOptions(parser))

parser.add_option("--readonly", default=False,
                  help="compute topology but do not update database",
                  action="store_true")

parser.add_option("--debug",
                  help="debug output",
                  action="store_true")

parser.add_option("--verify",
                  help="verify that assorted invariants are kept",
                  action="store_true")

parser.add_option("--list-verify-tests",
                  help=("list what verification actions are available "
                        "and do nothing else"),
                  action="store_true")

parser.add_option("--dot-file-dir", default=None,
                  help="Write Graphviz .dot files to this directory")

parser.add_option("--seed",
                  help="random number seed",
                  type=int, default=DEFAULT_RNG_SEED)

parser.add_option("--importldif",
                  help="import topology ldif file",
                  type=str, metavar="<file>")

parser.add_option("--exportldif",
                  help="export topology ldif file",
                  type=str, metavar="<file>")

parser.add_option("-H", "--URL",
                  help="LDB URL for database or target server",
                  type=str, metavar="<URL>", dest="dburl")

parser.add_option("--tmpdb",
                  help="schemaless database file to create for ldif import",
                  type=str, metavar="<file>")

parser.add_option("--now",
                  help=("assume current time is this ('YYYYmmddHHMMSS[tz]',"
                        " default: system time)"),
                  type=str, metavar="<date>")

parser.add_option("--forced-local-dsa",
                  help="run calculations assuming the DSA is this DN",
                  type=str, metavar="<DSA>")

parser.add_option("--attempt-live-connections", default=False,
                  help="Attempt to connect to other DSAs to test links",
                  action="store_true")

parser.add_option("--list-valid-dsas", default=False,
                  help=("Print a list of DSA dnstrs that could be"
                        " used in --forced-local-dsa"),
                  action="store_true")

parser.add_option("--test-all-reps-from", default=False,
                  help="Create and verify a graph of reps-from for every DSA",
                  action="store_true")

parser.add_option("--forget-local-links", default=False,
                  help="pretend not to know the existing local topology",
                  action="store_true")

parser.add_option("--forget-intersite-links", default=False,
                  help="pretend not to know the existing intersite topology",
                  action="store_true")

opts, args = parser.parse_args()


if opts.list_verify_tests:
    list_verify_tests()
    sys.exit(0)

if opts.test_all_reps_from:
    opts.readonly = True

if opts.debug:
    logger.setLevel(logging.DEBUG)
elif opts.readonly:
    logger.setLevel(logging.INFO)
else:
    logger.setLevel(logging.WARNING)

random.seed(opts.seed)

if opts.now:
    for timeformat in ("%Y%m%d%H%M%S%Z", "%Y%m%d%H%M%S"):
        try:
            now_tuple = time.strptime(opts.now, timeformat)
            break
        except ValueError:
            pass
    else:
        # else happens if break doesn't --> no match
        print("could not parse time '%s'" % (opts.now), file = sys.stderr)
        sys.exit(1)
    unix_now = int(time.mktime(now_tuple))
else:
    unix_now = int(time.time())

lp = sambaopts.get_loadparm()
# only log warnings/errors by default, unless the user has specified otherwise
if opts.debug is None:
    lp.set('log level', '1')

creds = credopts.get_credentials(lp, fallback_machine=True)

if opts.dburl is None:
    if opts.importldif:
        opts.dburl = opts.tmpdb
    else:
        opts.dburl = lp.samdb_url()
elif opts.importldif:
    logger.error("Don't use -H/--URL with --importldif, use --tmpdb instead")
    sys.exit(1)

# Instantiate Knowledge Consistency Checker and perform run
kcc = KCC(unix_now, readonly=opts.readonly, verify=opts.verify,
          debug=opts.debug, dot_file_dir=opts.dot_file_dir)

if opts.exportldif:
    rc = kcc.export_ldif(opts.dburl, lp, creds, opts.exportldif)
    sys.exit(rc)

if opts.importldif:
    if opts.tmpdb is None or opts.tmpdb.startswith('ldap'):
        logger.error("Specify a target temp database file with --tmpdb option")
        sys.exit(1)
    if os.path.exists(opts.tmpdb):
        logger.error("The temp database file (%s) specified with --tmpdb "
                     "already exists. We refuse to clobber it." % opts.tmpdb)
        sys.exit(1)

    rc = kcc.import_ldif(opts.tmpdb, lp, opts.importldif,
                         forced_local_dsa=opts.forced_local_dsa)
    if rc != 0:
        sys.exit(rc)


kcc.load_samdb(opts.dburl, lp, creds, force=False)

if opts.test_all_reps_from:
    test_all_reps_from(kcc, opts.dburl, lp, creds, unix_now,
                       rng_seed=opts.seed,
                       ldif_file=opts.importldif)
    sys.exit()

if opts.list_valid_dsas:
    print('\n'.join(kcc.list_dsas()))
    sys.exit()

try:
    rc = kcc.run(opts.dburl, lp, creds, opts.forced_local_dsa,
                 opts.forget_local_links, opts.forget_intersite_links,
                 attempt_live_connections=opts.attempt_live_connections)
    sys.exit(rc)

except GraphError as e:
    print( e)
    sys.exit(1)