#!/usr/bin/env python

# systemd-inhibit-delay
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.


import argparse
import dbus
import os
import subprocess
import sys
from dbus.mainloop.glib import DBusGMainLoop
from gi.repository import GLib

class Inhibitor:
    def __init__(self, bus, what, cmd):
        if what == 'sleep':
            self.signal_name = 'PrepareForSleep'
        elif what == 'shutdown':
            self.signal_name = 'PrepareForShutdown'
        else:
            raise Exception('for what, only sleep and shutdown supported')

        if cmd == '':
            raise Exception('command cannot be empty')

        self.bus = bus
        self.what = what
        self.cmd = cmd

    def start(self):
        self.bus.add_signal_receiver(
            self.sleep_handler,
            dbus_interface='org.freedesktop.login1.Manager',
            signal_name=self.signal_name
        )
        self.take_lock()

    def sleep_handler(self, active):
        if active:
            subprocess.call(self.cmd)
            if self.fd != -1:
                os.close(self.fd)
                self.fd = -1
        else:
            self.take_lock()

    def take_lock(self):
        login1 = self.bus.get_object('org.freedesktop.login1', '/org/freedesktop/login1')
        self.fd = login1.Inhibit(self.what, 'systemd-inhibit-delay', '', 'delay',
                dbus_interface='org.freedesktop.login1.Manager').take()

DBusGMainLoop(set_as_default=True)

parser = argparse.ArgumentParser(description='systemd inhibit delay')
parser.add_argument('cmd', help='the command to run (MUST EXIT WHEN READY)')
parser.add_argument('args', nargs=argparse.REMAINDER,
                    help='the command arguments')
parser.add_argument('--what', default='sleep',
                    help='what to delay, sleep or shutdown (default: sleep)')
args = parser.parse_args()

system_bus = dbus.SystemBus()
inhibitor = Inhibitor(system_bus, args.what, [args.cmd] + args.args)
inhibitor.start()
loop = GLib.MainLoop()
loop.run()