extra_credit

#!/usr/bin/env python3
#
# Author: Sami Menik, Fall 2022 
#  
# The program parses the time stamp of the current directory and calculate extra credit for 
# the submission.
# 
# Usage: extra_credit [<extra-credit-deadline> <extra-credit>] ...
# 
# Format of <extra-credit-deadline>: yyyy/mm/dd HH:MM:SS
# Type of <extra-credit> should be an int


import re
import os
import sys
from datetime import datetime

def cur_dir_name():
    directory_path = os.getcwd()
    return os.path.basename(directory_path)

def extract_datetime_suffix(dir_name):
    return dir_name[-31:-11]

def parse_datetime_str(datetime_str):
    # Format: yyyy/mm/dd HH:MM:SS
    return datetime.strptime(datetime_str, '%Y/%m/%d %H:%M:%S')

def parse_dir_datetime_suffix(dir_datetime_suffix):
    datetime_parts = re.search('([a-z]+)_+([0-9]+)_+([0-9]+)_+([0-9]+)_+([0-9]+)_+([0-9]+)', dir_datetime_suffix, re.IGNORECASE)
    month = datetime_parts.group(1)
    date = datetime_parts.group(2)
    hour = datetime_parts.group(3)
    min = datetime_parts.group(4)
    sec = datetime_parts.group(5)
    year = datetime_parts.group(6)
    parsable_datetime_str = '{}/{}/{} {}:{}:{}'.format(year, month, date, hour, min, sec)
    return datetime.strptime(parsable_datetime_str, '%Y/%b/%d %H:%M:%S')

def parse_cur_dir_datetime_suffix():
    curr_dir_name = cur_dir_name()
    dir_datetime_suffix = extract_datetime_suffix(curr_dir_name)
    date_time = parse_dir_datetime_suffix(dir_datetime_suffix)
    return date_time

def parse_extra_credit_deadline(deadline_str, credit):
    deadline = parse_datetime_str(deadline_str)
    credit = int(credit)
    return (deadline, credit)

def parse_extra_credit_deadlines(args):
    extra_credit_deadlines = []
    for i in range(0, len(args), 2):
        deadline_str = args[i]
        credit = args[i + 1]
        deadline_credit_pair = parse_extra_credit_deadline(deadline_str, credit)
        extra_credit_deadlines.append(deadline_credit_pair)
    return extra_credit_deadlines

def find_best_extra_credit(extra_creidt_deadlines, curr_dir_datetime):
    # Sort extra credit deadlines from earliest to latest.
    extra_creidt_deadlines.sort(key=lambda deadline_credit_pair: deadline_credit_pair[0])
    # Find the earliest applicable deadline.
    for deadline_credit_pair in extra_creidt_deadlines:
        (deadline, credit) = deadline_credit_pair
        if curr_dir_datetime <= deadline:
            return credit
    # No applicable extra credit deadline was found.
    return 0

def print_arg_format_error_msg():
    print('Call the program with the following args:', file=sys.stderr)
    print('extra_credit [<extra-credit-deadline> <extra-credit>] ...', file=sys.stderr)
    print('Format of <extra-credit-deadline>: yyyy/mm/dd HH:MM:SS', file=sys.stderr)

def print_extra_creidt_msg(extra_credit):
    if extra_credit > 0:
        print('The submission receives {} extra credits.'.format(extra_credit))
    else:
        print('The submission does not receive extra credit.')

def main():
    args = sys.argv[1:]

    if len(args) % 2 != 0:
        print_arg_format_error_msg()
        sys.exit(1)
    
    try:
        curr_dir_datetime = parse_cur_dir_datetime_suffix()
    except:
        print('Current directory does not have a valid date time suffix.', file=sys.stderr)
        sys.exit(1)
    
    try:
        extra_creidt_deadlines = parse_extra_credit_deadlines(args)
    except:
        print_arg_format_error_msg()
        sys.exit(1)
    
    extra_credit = find_best_extra_credit(extra_creidt_deadlines, curr_dir_datetime)

    print_extra_creidt_msg(extra_credit)

main()