#pylint: disable=C0111,R0903,W0212

"""Enable/disable automatic screen locking.

Requires the following executables:
    * xdg-screensaver
    * xdotool
    * xprop (as dependency for xdotool)
    * notify-send
"""

import logging
import os
import shutil
import psutil

import core.module
import core.widget
import core.input
import core.decorators

import util.cli

class Module(core.module.Module):
    @core.decorators.every(minutes=10)
    def __init__(self, config):
        super().__init__(config, core.widget.Widget(''))

        self.__active = False
        self.__xid = None

        core.input.register(self, button=core.input.LEFT_MOUSE, cmd=self.__toggle)

    def __check_requirements(self):
        requirements = ['xdotool', 'xprop', 'xdg-screensaver']
        missing = []
        for tool in requirements:
            if not shutil.which(tool):
                missing.append(tool)
        return missing

    def __get_i3bar_xid(self):
        xid = util.cli.execute('xdotool search --class \'i3bar\'').partition('\n')[0].strip()
        if xid.isdigit():
            return xid
        logging.warning('Module caffeine: xdotool couldn\'t get X window ID of \'i3bar\'.')
        return None

    def __notify(self):
        if not shutil.which('notify-send'):
            return

        if self.__active:
            util.cli.execute('notify-send \'Consuming caffeine\'')
        else:
            util.cli.execute('notify-send \'Out of coffee\'')

    def _suspend_screensaver(self):
        self.__xid = self.__get_i3bar_xid()
        if self.__xid is None:
            return False

        pid = os.fork()
        if pid == 0:
            os.setsid()
            util.cli.execute('xdg-screensaver suspend {}'.format(self.__xid))
            os._exit(0)
        else:
            os.waitpid(pid, 0)
        return True

    def __resume_screensaver(self):
        success = True
        xprop_path = shutil.which('xprop')
        pids = [ p.pid for p in psutil.process_iter() if p.cmdline() == [xprop_path, '-id', str(self.__xid), '-spy'] ]
        for pid in pids:
            try:
                os.kill(pid, 9)
            except OSError:
                success = False
        return success

    def state(self, _):
        if self.__active:
            return 'activated'
        return 'deactivated'

    def __toggle(self, _):
        missing = self.__check_requirements()
        if missing:
            logging.warning('Could not run caffeine - missing %s!', ', '.join(missing))
            return

        self.__active = not self.__active
        if self.__active:
            success = self._suspend_screensaver()
        else:
            success = self.__resume_screensaver()

        if success:
            self.__notify()
        else:
            self.__active = not self.__active

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