#!/usr/bin/python
# Copyright 2016 Red Hat, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import argparse
import logging
import os
import pwd
import shutil
import socket
import subprocess
import sys
import time
import copy
import tempfile
from subprocess import CalledProcessError
import getpass
from string import Template
from six.moves import input
from six.moves.configparser import ConfigParser
from ipapython.ipautil import run, kinit_password, user_input
from ipalib import api
from ipalib import errors


DATADIR = '/usr/share/novajoin'
NOVADIR = '/etc/nova'
IPACONF = '/etc/ipa/default.conf'
JOINCONF = '/etc/join/join.conf'
KEYTAB = '/etc/join/krb5.keytab'


class ConfigurationError(StandardError):

    def __init__(self, message):
        StandardError.__init__(self, message)


LOGFILE = '/var/log/novajoin-install.log'
logger = logging.getLogger()


def openlogs():
    global logger  # pylint: disable=W0603
    if os.path.isfile(LOGFILE):
        try:
            created = '%s' % time.strftime(
                '%Y%m%d%H%M%SZ', time.gmtime(os.path.getctime(LOGFILE)))
            shutil.move(LOGFILE, '%s.%s' % (LOGFILE, created))
        except IOError:
            pass
    logger = logging.getLogger()
    try:
        lh = logging.FileHandler(LOGFILE)
    except IOError as e:
        print >> sys.stderr, 'Unable to open %s (%s)' % (LOGFILE, str(e))
        lh = logging.StreamHandler(sys.stderr)
    formatter = logging.Formatter('[%(asctime)s] %(message)s')
    lh.setFormatter(formatter)
    lh.setLevel(logging.DEBUG)
    logger.addHandler(lh)
    logger.propagate = False
    ch = logging.StreamHandler(sys.stdout)
    formatter = logging.Formatter('%(message)s')
    ch.setFormatter(formatter)
    ch.setLevel(logging.INFO)
    logger.addHandler(ch)


def write_from_template(destfile, template, opts):
    with open(template) as f:
        t = Template(f.read())
    text = t.substitute(**opts)
    with open(destfile, 'w+') as f:
        f.write(text)
    logger.debug(destfile)
    logger.debug(text)


def install(args):
    logger.info('Installation initiated')

    if not os.path.exists('/etc/ipa/default.conf'):
        raise ConfigurationError('Must be enrolled in IPA')

    api.bootstrap(context='novajoin')
    api.finalize()

    ccache_dir = tempfile.mkdtemp(prefix='krbcc')

    ccache_name = os.path.join(ccache_dir, 'ccache')
    env = {"PATH":
           "/bin:/sbin:/usr/kerberos/bin:/usr/kerberos/sbin:/usr/bin:/usr/sbin"
           }
    env['KRB5CCNAME'] = os.environ['KRB5CCNAME'] = ccache_name

    principal = args['principal']
    if principal.find('@') == -1:
        principal = '%s@%s' % (principal, api.env.realm)

    try:
        kinit_password(principal, args['password'], ccache_name)
    except RuntimeError as e:
        raise ConfigurationError("Kerberos authentication failed: %s" % e)

    api.Backend.rpcclient.connect()

    try:
        result = api.Command.service_add(u'nova/%s@%s' %
                                         (args['hostname'], api.env.realm),
                                         force=True)
    except errors.DuplicateEntry:
        pass
    except Exception as e:
        raise ConfigurationError(
            'Failed to add service: %s' % e)

    try:
        if os.path.exists(KEYTAB):
            os.unlink(KEYTAB)
    except OSError as e:
        raise ConfigurationError(
            'Could not remove %s: %s' % (KEYTAB, e)
        )

    run(['ipa-getkeytab',
         '-s', api.env.server,
         '-p', 'nova/%s@%s' % (args['hostname'], api.env.realm),
         '-k', KEYTAB],
        env=env)

    logger.info('Installing default config files')

    confopts = {'FQDN': args['hostname'],
                'MASTER': api.env.server,  # pylint: disable=no-member
                'DOMAIN': api.env.domain,  # pylint: disable=no-member
                'KEYSTONE_AUTH_URI': args['keystone_auth_uri'],
                'KEYSTONE_AUTH_URL': args['keystone_auth_url'],
                'KEYSTONE_IDENTITY': args['keystone_identity'],
                'NOVA_PASSWORD': args['nova_password'],
                }

    write_from_template(JOINCONF,
                        os.path.join(DATADIR, 'join.conf.template'),
                        confopts)

    FILES = ['cloud-config.json']
    for fn in FILES:
        dst = os.path.join(NOVADIR, fn)
        source = os.path.join(DATADIR, fn)
        logger.info('Installing %s' % dst)
        shutil.copyfile(source, dst)

    config = ConfigParser()
    config.read('/etc/nova/nova.conf')
    config.set('DEFAULT',
               'vendordata_jsonfile_path',
               '/etc/nova/cloud-config.json')

    # set the default domain to the IPA domain. This is added to the
    # instance name to set the hostname.
    config.set('DEFAULT',
               'dhcp_domain',
               api.env.domain)

    with open('/etc/nova/nova.conf', 'w') as f:
        config.write(f)

    try:
        user = pwd.getpwnam(args['user'])
    except KeyError:
        raise ConfigurationError('User: %s not found on the system' %
                                 args['user'])

    os.chown(KEYTAB, user.pw_uid, user.pw_gid)
    os.chmod(KEYTAB, 0o600)

    logger.info('Importing IPA metadata')
    (stdout, stderr, returncode) = run(
        ['glance',
         'md-namespace-import',
         '--file',
         '/usr/share/novajoin/freeipa.json'], raiseonerr=False)
    if returncode != 0:
        logger.error('Adding IPA metadata failed: %s' % stderr)

    logger.info('Creating IPA permissions')
    (stdout, stderr, returncode) = run(
        ['/usr/libexec/novajoin-ipa-setup.sh'], raiseonerr=False)
    if returncode != 0:
        logger.error('Creating IPA permissions failed')


def parse_args():
    parser = argparse.ArgumentParser(description='Nova join Install Options')
    parser.add_argument('--hostname',
                        help='Machine\'s fully qualified host name')
    parser.add_argument('--user',
                        help='User that nova services run as',
                        default='nova')
    parser.add_argument('--principal', dest='principal', default='admin',
                        help='principal to use to setup IPA integration')
    parser.add_argument('--password', dest='password',
                        help='password for the principal')
    parser.add_argument('--password-file', dest='passwordfile',
                        help='path to file containing password for '
                             'the principal')
    parser.add_argument('--keystone-auth-uri', dest='keystone_auth_uri',
                        help='Keystone auth URI')
    parser.add_argument('--keystone-auth-url', dest='keystone_auth_url',
                        help='Keystone auth URL')
    parser.add_argument('--keystone-identity', dest='keystone_identity',
                        help='Keystone identity URI')
    parser.add_argument('--nova-password', dest='nova_password',
                        help='Nova service user password')

    args = vars(parser.parse_args())

    if not args['principal']:
        args['principal'] = user_input("IPA admin user", "admin",
                                       allow_empty=False)

    if args['passwordfile']:
        try:
            with open(args['passwordfile']) as f:
                args['password'] = f.read()
        except IOError as e:
            raise ConfigurationError('Unable to read password file: %s'
                                     % e)
    if not args['password']:
        try:
            args['password'] = getpass.getpass("Password for %s: " %
                                               args['principal'])
        except EOFError:
            args['password'] = None
        if not args['password']:
            raise ConfigurationError('Password must be provided.')

    if not args['hostname']:
        args['hostname'] = socket.getfqdn()

    if len(args['hostname'].split('.')) < 2:
        raise ConfigurationError('Hostname: %s is not a FQDN' %
                                 args['hostname'])

    if not args['keystone_auth_uri']:
        args['keystone_auth_uri'] = user_input("Keysone auth URI", "",
                                           allow_empty=False)

    if not args['keystone_auth_url']:
        args['keystone_auth_url'] = user_input("Keysone auth URL", "",
                                           allow_empty=False)

    if not args['keystone_identity']:
        args['keystone_identity'] = user_input("Keysone identity URI", "",
                                               allow_empty=False)

    if not args['nova_password']:
        try:
            args['nova_password'] = getpass.getpass("nova service Password: ")
        except EOFError:
            args['nova_password'] = None
        if not args['nova_password']:
            raise ConfigurationError('nova service user password required.')

    try:
        pwd.getpwnam(args['user'])
    except KeyError:
        raise ConfigurationError('User: %s not found on the system' %
                                 args['user'])

    return args

if __name__ == '__main__':
    opts = []
    out = 0
    openlogs()
    logger.setLevel(logging.DEBUG)

    try:
        opts = parse_args()

        logger.debug('Installation arguments:')
        for k in sorted(opts.iterkeys()):
            logger.debug('%s: %s', k, opts[k])

        install(opts)
    except Exception as e:  # pylint: disable=broad-except
        logger.info(str(e))          # emit message to console
        logger.debug(e, exc_info=1)  # add backtrace information to logfile

        logger.info('Installation aborted.')
        logger.info('See log file %s for details' % LOGFILE)
        out = 1
    except SystemExit:
        out = 1
        raise
    finally:
        if out == 0:
            logger.info('Installation complete.')
            logger.info(
                'Please restart nova-api to enable the join service.')
    sys.exit(out)