todo

#!/usr/bin/env python3

import argparse
import os

def main(todo_file, argv):
    if (argv.add):
        add_task(todo_file, argv.add)
    elif (argv.delete):
        delete_task(todo_file, argv.delete)
    else:
        show_list(todo_file)

def add_task(todo_file, message):
    with open(todo_file, 'a+') as todo:
        todo.write('{:s}\n'.format(message[0]))

def show_list(todo_file):
    try:
        with open(todo_file, 'r') as todo:
            index = 1
            tasks = [x.rstrip() for x in todo.readlines()]
            if (tasks):
                for task in tasks:
                    print('{:d}:\t{:s}'.format(index, task))
                    index += 1
            else:
                print('No tasks in todo file ...')
    except IOError as e:
        print('No tasks in todo file ...')

def delete_task(todo_file, index):
    try:
        with open(todo_file, 'r+') as todo:
            tasks = [x.rstrip() for x in todo.readlines()]
            try:
                deleted = tasks.pop(index-1)
                print('Deleted: {:s}'.format(deleted))
                todo.seek(0)
                todo.truncate()
                for task in tasks:
                    todo.write('{:s}\n'.format(task))
            except IndexError as e:
                print('Task non-existant ...')
    except IOError as e:
        print('No tasks in todo file ...')

if __name__ == '__main__':
    todo_file = os.path.expanduser('~') + '/.todo'
    argparser = argparse.ArgumentParser()
    argparser.add_argument('-a', '--add', nargs='+',
        help='add task to todo-list.')
    argparser.add_argument('-d', '--delete', type=int,
        nargs='?', help='delete item with index [i]')
    argv = argparser.parse_args()
    main(todo_file, argv)