#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
#       shutdown timer version 1.0 stable
#
#       Copyright 2009 Aneesh <aneesh.nl@gmail.com>
#
#       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 2 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, write to the Free Software
#       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#       MA 02110-1301, USA.

'''
Shut down the system after specified time.
usage : shutdown.py <hours> <minutes> <seconds>
This currently works only on GNU/Linux
'''
import time, sys, os

def clearscreen(numlines=100):
    '''
    Clears the screen.
    This function clears the screen according to OS of the user.
    Credits : Balamurugan S balamurugan.sekar <at> gmail <dot> com.
    '''
    if os.name == 'posix': # eg : Unix or GNU/Linux
        os.system('clear')
    elif os.name in ('nt', 'dos', 'ce'): # Windows, Dos etc.
        os.system('cls')
    else:
        # Other OS. New line 100 times, in effect clear the screen.
        print('\n' * numlines)

def main():
    '''Main function
    calculate the variables hours, minutes, seconds from
    command line arguments and pass to timer().
    After timer() has compleated, it runs the command 'init 0' to
    shutdown system.'''
    try:
        hours   = int(sys.argv[1]) # This 3 lines calculates hours,
        minutes = int(sys.argv[2]) # minutes, seconds from command
        seconds = int(sys.argv[3]) # line arguments
    except:
        print('''
Usage : shutdowntimer <hours> <minutes> <seconds>

Copyright 2009 Aneesh <aneesh.nl@gmail.com>
For more details, view licence''')
        exit()
    # provides time delay and prints out time remaining.
    timer(hours, minutes, seconds)
    print('Shuting down ...')
    os.system('init 0') # shut down the system
    return 0

def timer(hours, minutes, seconds):
    '''Provides time delay
    Accepts hours, minutes and seconds as int.
    Prints the remaining time in each second.
    '''
    try:
        while True:
            clearscreen()
            print('Shutting down in {0} hours {1} minutes {2} seconds'\
        .format(hours, minutes, seconds))
            # provides a time delay of 1 second
            time.sleep(1)
            # if...elif...else ladder.
            if seconds > 0:
                seconds -= 1  # decrement seconds
            elif minutes > 0: # when seconds = 0, this condition become true
                minutes -= 1  # decement minutes
                seconds = 59  # reset seconds
            elif hours > 0:   # when seconds = 0 & minutes =0,
                              # this condition become true
                hours -=1     # decrement hours
                minutes = 59  # reset minutes
            else: # if hours, minutes & seconds = 0
                return None # exit from function

    except KeyboardInterrupt:
        print('''
You cancelled the shutdown.. Thanks for using.

       shutdowntimer version 1.0 stable

       Copyright 2009 Aneesh <aneesh.nl@gmail.com>

       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, write to the Free Software
       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
       MA 02110-1301, USA.''')
        exit()

if __name__ == '__main__':
    main()