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

import argparse
import json
import sys

from plinth import action_utils

TRANSMISSION_CONFIG = '/etc/transmission-daemon/settings.json'


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('get-configuration',
                          help='Return the current configuration')
    subparsers.add_parser(
        'merge-configuration',
        help='Merge JSON configuration from stdin with existing')

    subparsers.required = True
    return parser.parse_args()


def subcommand_get_configuration(_):
    """Return the current configuration in JSON format."""
    configuration = open(TRANSMISSION_CONFIG, 'r').read()
    print(configuration)


def subcommand_merge_configuration(arguments):
    """Merge given JSON configuration with existing configuration."""
    configuration = sys.stdin.read()
    configuration = json.loads(configuration)

    current_configuration = open(TRANSMISSION_CONFIG, 'r').read()
    current_configuration = json.loads(current_configuration)

    new_configuration = current_configuration
    new_configuration.update(configuration)
    new_configuration = json.dumps(new_configuration, indent=4, sort_keys=True)

    open(TRANSMISSION_CONFIG, 'w').write(new_configuration)
    action_utils.service_reload('transmission-daemon')


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()