#!/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 searx.
"""

import argparse
import os
import secrets
import shutil

from plinth import action_utils
from plinth.utils import YAMLFile, gunzip


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('enable', help='Enable searx')
    subparsers.add_parser('disable', help='Disable searx')
    subparsers.add_parser(
        'setup', help="Perform post-installation operations for Searx")

    subparsers.required = True
    return parser.parse_args()


def _copy_uwsgi_configuration():
    """Copy example uwsgi configuration

    Copy the example uwsgi configuration shipped with Searx documentation to
    the appropriate uwsgi directory.
    """
    example_config = ('/usr/share/doc/searx/examples/'
                      'uwsgi/apps-available/searx.ini')
    destination = '/etc/uwsgi/apps-available/'

    if not os.path.exists(destination):
        shutil.copy(example_config, destination)
        action_utils.webserver_enable('uwsgi', kind='module')


def _generate_secret_key():
    """ Generate a secret key for the Searx installation."""
    settings_file = '/etc/searx/settings.yml'

    # Create settings file if not exists
    if not os.path.exists(settings_file):
        example_settings_file = '/usr/share/doc/searx/examples/settings.yml.gz'
        gunzip(example_settings_file, settings_file)

    # Generate and set a secret key
    with YAMLFile(settings_file) as settings:
        secret_key = secrets.token_hex(32)
        settings['server']['secret_key'] = secret_key

    action_utils.service_restart('uwsgi')


def subcommand_setup(_):
    """Post installation actions for Searx"""
    _copy_uwsgi_configuration()
    _generate_secret_key()


def subcommand_enable(_):
    """Enable web configuration and reload."""
    # TODO Write action_utils functions for enable/disable uwsgi
    os.symlink('/etc/uwsgi/apps-available/searx.ini',
               '/etc/uwsgi/apps-enabled/')
    action_utils.webserver_enable('searx-freedombox')


def subcommand_disable(_):
    """Disable web configuration and reload."""
    action_utils.webserver_disable('searx-freedombox')
    os.unlink('/etc/uwsgi/apps-enabled/searx.ini')


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()