#!/usr/bin/python3
# SPDX-License-Identifier: AGPL-3.0-or-later
"""
Configuration helper for Syncthing.
"""

import argparse
import grp
import os
import pwd
import shutil
import subprocess
import time

import augeas

from plinth import action_utils

DATA_DIR = '/var/lib/syncthing'
CONF_FILE = DATA_DIR + '/.config/syncthing/config.xml'


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

    subparsers.add_parser('setup', help='Setup Syncthing')

    subparsers.add_parser('setup-config', help='Setup Syncthing configuration')

    subparsers.required = True
    return parser.parse_args()


def augeas_load():
    """Initialize Augeas."""
    aug = augeas.Augeas(flags=augeas.Augeas.NO_LOAD +
                        augeas.Augeas.NO_MODL_AUTOLOAD)
    aug.add_transform('Xml.lns', CONF_FILE)
    aug.load()
    return aug


def subcommand_setup(_):
    """Actions to be performed before installing Syncthing"""
    # Create syncthing group if needed.
    try:
        grp.getgrnam('syncthing')
    except KeyError:
        subprocess.run(['addgroup', '--system', 'syncthing'], check=True)

    # Create syncthing user if needed.
    try:
        pwd.getpwnam('syncthing')
    except KeyError:
        subprocess.run([
            'adduser', '--system', '--ingroup', 'syncthing', '--home',
            DATA_DIR, '--gecos', 'Syncthing file synchronization server',
            'syncthing'
        ], check=True)

    if not os.path.exists(DATA_DIR):
        os.makedirs(DATA_DIR, mode=0o750)
        shutil.chown(DATA_DIR, user='syncthing', group='syncthing')


def subcommand_setup_config(_):
    """Make configuration changes."""
    # wait until the configuration file is created by the syncthing daemon
    timeout = 300
    while timeout > 0:
        if os.path.exists(CONF_FILE):
            break
        timeout = timeout - 1
        time.sleep(1)

    aug = augeas_load()

    # disable authentication missing notification as FreedomBox itself
    # provides authentication
    auth_conf = ('/configuration/options/unackedNotificationID'
                 '[#text="authenticationUserAndPassword"]')
    conf_changed = bool(aug.remove('/files' + CONF_FILE + auth_conf))

    # disable usage reporting notification by declining reporting
    # if the user has not made a choice yet
    usage_conf = '/configuration/options/urAccepted/#text'
    if aug.get('/files' + CONF_FILE + usage_conf) == '0':
        aug.set('/files' + CONF_FILE + usage_conf, '-1')
        conf_changed = True

    aug.save()

    if conf_changed:
        action_utils.service_try_restart('syncthing@syncthing')


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()