#!/usr/bin/python3
# -*- mode: python -*-
#
# This file is part of Plinth.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

"""
Configuration helper for the ejabberd service
"""

import argparse
import subprocess
import os
import socket
import re
import yaml

JWCHAT_CONFIG = '/etc/jwchat/config.js'
EJABBERD_CONFIG = '/etc/ejabberd/ejabberd.yml'
EJABBERD_BACKUP = '/var/log/ejabberd/ejabberd.dump'
EJABBERD_BACKUP_NEW = '/var/log/ejabberd/ejabberd_new.dump'


def parse_arguments():
    """Return parsed command line arguments as dictionary"""
    parser = argparse.ArgumentParser()
    subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')

    # Prepare ejabberd for hostname change
    pre_hostname_change = subparsers.add_parser(
        'pre-change-hostname',
        help='Prepare ejabberd for nodename change')
    pre_hostname_change.add_argument('--old-hostname',
                                     help='Previous hostname')
    pre_hostname_change.add_argument('--new-hostname',
                                     help='New hostname')

    # Update ejabberd nodename
    hostname_change = subparsers.add_parser('change-hostname',
                                            help='Update ejabberd nodename')
    hostname_change.add_argument('--old-hostname',
                                 help='Previous hostname')
    hostname_change.add_argument('--new-hostname',
                                 help='New hostname')

    # Update ejabberd and jwchat with new domainname
    domainname_change = subparsers.add_parser(
        'change-domainname',
        help='Update ejabberd and jwchat with new domainname')
    domainname_change.add_argument('--domainname', help='New domainname')

    # Get the list of all virtual hosts configured in ejabberd
    subparsers.add_parser(
        'get-vhosts',
        help='Get the list of all virtual hosts configured in ejabberd')

    # Register a new user account
    register = subparsers.add_parser('register',
                                     help='Register a new user account')
    register.add_argument('--username',
                          help='Username for the new user account')
    register.add_argument('--vhost',
                          help='Virtual host to register the new user in')
    register.add_argument('--password',
                          help='Password for the new user account')

    return parser.parse_args()


def subcommand_pre_change_hostname(arguments):
    """Prepare ejabberd for hostname change"""
    old_hostname = arguments.old_hostname
    new_hostname = arguments.new_hostname

    subprocess.call(['ejabberdctl', 'backup', EJABBERD_BACKUP])
    try:
        subprocess.check_output(['ejabberdctl', 'mnesia-change-nodename',
                                 'ejabberd@' + old_hostname,
                                 'ejabberd@' + new_hostname,
                                 EJABBERD_BACKUP, EJABBERD_BACKUP_NEW])
        os.remove(EJABBERD_BACKUP)
    except subprocess.CalledProcessError as err:
        print('Failed to change hostname in ejabberd backup database: %s', err)


def subcommand_change_hostname(arguments):
    """Update ejabberd and jwchat with new hostname"""
    subprocess.call(['service', 'ejabberd', 'stop'])
    subprocess.call(['pkill', '-u', 'ejabberd'])

    # Make sure there aren't files in the Mnesia spool dir
    os.makedirs('/var/lib/ejabberd/oldfiles', exist_ok=True)
    subprocess.call('mv /var/lib/ejabberd/*.* /var/lib/ejabberd/oldfiles/',
                    shell=True)

    subprocess.call(['service', 'ejabberd', 'start'])

    # restore backup database
    if os.path.exists(EJABBERD_BACKUP_NEW):
        try:
            subprocess.check_output(['ejabberdctl',
                                     'restore',
                                     EJABBERD_BACKUP_NEW])
            os.remove(EJABBERD_BACKUP_NEW)
        except subprocess.CalledProcessError as err:
            print('Failed to restore ejabberd backup database: %s', err)
    else:
        print('Could not load ejabberd backup database: %s not found'
              % EJABBERD_BACKUP_NEW)


def subcommand_change_domainname(arguments):
    """Update ejabberd and jwchat with new domainname"""
    domainname = arguments.domainname.strip("'")
    if not domainname:
        # If new domainname is blank, use hostname instead.
        domainname = socket.gethostname()

    # update jwchat's sitename, if it's installed
    if os.path.exists(JWCHAT_CONFIG):
        with open(JWCHAT_CONFIG, 'r') as conffile:
            lines = conffile.readlines()
        with open(JWCHAT_CONFIG, 'w') as conffile:
            for line in lines:
                if re.match(r'\s*var\s+SITENAME', line):
                    conffile.write('var SITENAME = "' + domainname + '";\n')
                else:
                    conffile.write(line)
    else:
        print('Skipping configuring jwchat sitename: %s not found',
              JWCHAT_CONFIG)

    # Check if new domainname is already in ejabberd hosts list.
    conffile = open(EJABBERD_CONFIG, 'r')
    conf = yaml.safe_load(conffile)
    if domainname in conf['hosts']:
        return

    subprocess.call(['service', 'ejabberd', 'stop'])
    subprocess.call(['pkill', '-u', 'ejabberd'])

    # Add updated domainname to ejabberd hosts list.
    with open(EJABBERD_CONFIG, 'r') as conffile:
        lines = conffile.readlines()
    with open(EJABBERD_CONFIG, 'w') as conffile:
        for line in lines:
            conffile.write(line)
            if re.match(r'\s*hosts:', line):
                conffile.write('  - "' + domainname + '"\n')

    subprocess.call(['service', 'ejabberd', 'start'])


def subcommand_get_vhosts(_):
    """Get list of all virtual hosts configured in ejabbered."""
    subprocess.call(['ejabberdctl', 'registered_vhosts'])


def subcommand_register(arguments):
    """Register a new user account."""
    username = arguments.username
    vhost = arguments.vhost
    password = arguments.password

    try:
        output = subprocess.check_output(['ejabberdctl', 'register',
                                          username, vhost, password])
        print(output.decode())
    except subprocess.CalledProcessError as e:
        print('Failed to register XMPP account:', e.output.decode())


def main():
    """Parse arguments and perform all duties"""
    arguments = parse_arguments()

    subcommand = arguments.subcommand.replace('-', '_')
    subcommand_method = globals()['subcommand_' + subcommand]
    subcommand_method(arguments)


if __name__ == '__main__':
    main()
