"""
libremanage - Lightweight, free software for remote side-chanel server management

Copyright (C) 2018 Alyssa Rosenzweig

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 <https://www.gnu.org/licenses/>.
"""

import sys
import json
import functools

USAGE = """
Usage:

    $ libremanage [server name] [command]

Example:

    $ libremanage web2 reboot

Server names are defined in the accompanying config.py.

Valid commands are as follows:

    - shutdown, reboot, poweron: Power management
    - tty: Open TTY in GNU Screen
"""

with open("config.json") as f:
    CONFIG = json.load(f)
print(CONFIG)

def die_with_usage(message):
    print(message)
    print(USAGE)
    sys.exit(1)

if len(sys.argv) != 3:
    die_with_usage("Incorrect number of arguments")

def get_server_handle(name):
    # TODO: resolve based on config, SSH in, give self-contained handle?
    return name

def set_server_power(state, server):
    print("Setting server " + server + " to power state " + str(state))

COMMANDS = {
        # Power managemment

        "shutdown": (False, functools.partial(set_server_power, 0)),
        "poweron": (False, functools.partial(set_server_power, 1)),
        "reboot": (False, lambda s: (set_server_power(0, s), set_server_power(1, s))),

        # TTY access (or keyboard if wired as such)

        "tty": (True, lambda s: print("Screening on " + s))
}

def issue_command(server_name, command):
    server = get_server_handle(server_name)
    print(server_name, command)

    try:
        (visible_shell, callback) = COMMANDS[command]
    except KeyError:
        die_with_usage("Invalid command supplied")

    print("Shell visible? " + str(visible_shell))
    callback(server_name)

issue_command(sys.argv[1], sys.argv[2])