#!/usr/bin/env python3
#
#       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.

import sys

def main():
    if len(sys.argv) == 1:
        read = get_int("Read? ")
        total = get_int("Total? ")
    elif len(sys.argv) >= 3:
        read, total = user_input()
    # Help message, user can enter -h or --help because it will not make the previous statements true
    else:
        print("Usage: {0} [read total]".format(sys.argv[0]),
              "\nArguments not required, but must be used together.")
        sys.exit()
    not_read = total - read
    half = total // 2
    print_info(read, not_read, half, total)

def get_int(msg):
    while True:
        i = input(msg)
        try:
            return int(i)
        except ValueError as err:
            print(err)
            continue

def user_input():
    try:
        read = int(sys.argv[1])
        total = int(sys.argv[2])
        return read, total
    except ValueError as err:
        print(err)
        sys.exit()

def print_info(read, not_read, half, total):
    if read > total:
        print(" Ha, funny, you read {0} pages, but there are only {1} total?".format(read, total))
    elif read == total:
        print(" Really? You're done with {0} pages?".format(total))
    elif read == 0:
        print(" Um? You haven't even start a book with {0} pages?".format(total))
    elif read < half:
        print(" There are {0} pages total. \n You have only read {1} pages. \n There are {2} pages that you haven't read!".format(
              total, read, not_read))
    elif read > half:
        print(" There are {0} pages total. \n You read {1} pages. \n Almost there, only {2} pages that you haven't read!".format(
              total, read, not_read))
    elif read == half:
        print(" There are {0} pages total. \n You read {1} pages. \n There are {2} pages that you haven't read. \n Congrats, you at the halfway point!".format(
              total, read, not_read))

if __name__ == "__main__":
    main()