#!/usr/bin/env python3
#
# Copyright (C) 2019 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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 pwd
import grp
import traceback
from datetime import datetime

from vyos.defaults import directories
from vyos.configsession import ConfigSession, ConfigSessionError
from vyos.configtree import ConfigTree
from vyos.util import cmd

STATUS_FILE = '/tmp/vyos-config-status'
TRACE_FILE = '/tmp/boot-config-trace'

CFG_GROUP = 'vyattacfg'

trace_config = False

if 'log' in directories:
    LOG_DIR = directories['log']
else:
    LOG_DIR = '/var/log/vyatta'

LOG_FILE = LOG_DIR + '/vyos-boot-config-loader.log'

try:
    with open('/proc/cmdline', 'r') as f:
        cmdline = f.read()
    if 'vyos-debug' in cmdline:
        os.environ['VYOS_DEBUG'] = 'yes'
    if 'vyos-config-debug' in cmdline:
        os.environ['VYOS_DEBUG'] = 'yes'
        trace_config = True
except Exception as e:
    print('{0}'.format(e))

def write_config_status(status):
    try:
        with open(STATUS_FILE, 'w') as f:
            f.write('{0}\n'.format(status))
    except Exception as e:
        print('{0}'.format(e))

def trace_to_file(trace_file_name):
    try:
        with open(trace_file_name, 'w') as trace_file:
            traceback.print_exc(file=trace_file)
    except Exception as e:
        print('{0}'.format(e))

def failsafe(config_file_name):
    fail_msg = """
    !!!!!
    There were errors loading the configuration
    Please examine the errors in
    {0}
    and correct
    !!!!!
    """.format(TRACE_FILE)

    print(fail_msg, file=sys.stderr)

    users = [x[0] for x in pwd.getpwall()]
    if 'vyos' in users:
        return

    try:
        with open(config_file_name, 'r') as f:
            config_file = f.read()
    except Exception as e:
        print("Catastrophic: no default config file "
              "'{0}'".format(config_file_name))
        sys.exit(1)

    config = ConfigTree(config_file)
    if not config.exists(['system', 'login', 'user', 'vyos',
                          'authentication', 'encrypted-password']):
        print("No password entry in default config file;")
        print("unable to recover password for user 'vyos'.")
        sys.exit(1)
    else:
        passwd = config.return_value(['system', 'login', 'user', 'vyos',
                                      'authentication',
                                      'encrypted-password'])

    cmd(f"useradd -s /bin/bash -G 'users,sudo' -m -N -p '{passwd}' vyos")

if __name__ == '__main__':
    if len(sys.argv) < 2:
        print("Must specify boot config file.")
        sys.exit(1)
    else:
        file_name = sys.argv[1]

    # Set user and group options, so that others will be able to commit
    # Currently, the only caller does 'sg CFG_GROUP', but that may change
    cfg_group = grp.getgrnam(CFG_GROUP)
    os.setgid(cfg_group.gr_gid)

    # Need to set file permissions to 775 so that every vyattacfg group
    # member has write access to the running config
    os.umask(0o002)

    session = ConfigSession(os.getpid(), 'vyos-boot-config-loader')
    env = session.get_session_env()

    default_file_name = env['vyatta_sysconfdir'] + '/config.boot.default'

    try:
        with open(file_name, 'r') as f:
            config_file = f.read()
    except Exception:
        write_config_status(1)
        if trace_config:
            failsafe(default_file_name)
            trace_to_file(TRACE_FILE)
        sys.exit(1)

    try:
        time_begin_load = datetime.now()
        load_out = session.load_config(file_name)
        time_end_load = datetime.now()
        time_begin_commit = datetime.now()
        commit_out = session.commit()
        time_end_commit = datetime.now()
        write_config_status(0)
    except ConfigSessionError:
        # If here, there is no use doing session.discard, as we have no
        # recoverable config environment, and will only throw an error
        write_config_status(1)
        if trace_config:
            failsafe(default_file_name)
            trace_to_file(TRACE_FILE)
        sys.exit(1)

    time_elapsed_load = time_end_load - time_begin_load
    time_elapsed_commit = time_end_commit - time_begin_commit

    try:
        if not os.path.exists(LOG_DIR):
            os.mkdir(LOG_DIR)
        with open(LOG_FILE, 'a') as f:
            f.write('\n\n')
            f.write('{0}    Begin config load\n'
                    ''.format(time_begin_load))
            f.write(load_out)
            f.write('{0}    End config load\n'
                    ''.format(time_end_load))
            f.write('Elapsed time for config load: {0}\n'
                    ''.format(time_elapsed_load))
            f.write('{0}    Begin config commit\n'
                    ''.format(time_begin_commit))
            f.write(commit_out)
            f.write('{0}    End config commit\n'
                    ''.format(time_end_commit))
            f.write('Elapsed time for config commit: {0}\n'
                    ''.format(time_elapsed_commit))
    except Exception as e:
        print('{0}'.format(e))