#!/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 re
import time
import os

JWCHAT_CONFIG = '/etc/jwchat/config.js'
EJABBERD_CONFIG = '/etc/ejabberd/ejabberd.yml'
EJABBERD_BACKUP = '/tmp/ejabberd.dump'


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

    # Get whether ejabberd is installed
    subparsers.add_parser('get-installed',
                          help='Get whether ejabberd is installed')

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

    # 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('--password',
                          help='Password for the new user account')

    return parser.parse_args()


def subcommand_get_installed(_):
    """Get whether ejabberd is installed"""
    print('installed' if get_installed() else 'not installed')


def subcommand_change_hostname(arguments):
    """Update ejabberd and jwchat with new hostname"""
    if not get_installed():
        print('Failed to update XMPP hostname: ejabberd is not installed.')

    old_hostname = arguments.old_hostname
    new_hostname = arguments.new_hostname

    with open(JWCHAT_CONFIG, 'r') as conffile:
        lines = conffile.readlines()
    with open(JWCHAT_CONFIG, 'w') as conffile:
        for line in lines:
            conffile.write(re.sub('var SITENAME = "' + old_hostname + '";',
                                  'var SITENAME = "' + new_hostname + '";',
                                  line))

    with open(EJABBERD_CONFIG, 'r') as conffile:
        lines = conffile.readlines()
    with open(EJABBERD_CONFIG, 'w') as conffile:
        for line in lines:
            conffile.write(re.sub(old_hostname, new_hostname, line))

    with open(EJABBERD_BACKUP, 'r') as dumpfile:
        lines = dumpfile.readlines()
    with open(EJABBERD_BACKUP, 'w') as dumpfile:
        for line in lines:
            dumpfile.write(re.sub(old_hostname, new_hostname, line))

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

    # load backup database
    time.sleep(10)
    subprocess.call(['ejabberdctl', 'load', EJABBERD_BACKUP])
    os.remove(EJABBERD_BACKUP)


def subcommand_register(arguments):
    """Register a new user account"""
    if not get_installed():
        print('Failed to register XMPP account: ejabberd is not installed.')
        return

    username = arguments.username
    password = arguments.password
    hostname = subprocess.check_output(['hostname'])

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


def get_installed():
    """Check if ejabberd is installed"""
    with open('/dev/null', 'w') as file_handle:
        status = subprocess.call(['which', 'ejabberdctl'], stdout=file_handle)

    return not status


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()