thing.py

import datetime
import math
import sys

def main(argv):
    try:
        goal = int(argv[1])
        current = float(argv[2])
    except:
        return f"Usage: {argv[0]} <goal:int> <current:int>"

    total_days = (
        datetime.date(datetime.date.today().year, 12, 31).timetuple().tm_yday
    )
    today = datetime.date.today().timetuple().tm_yday
    remaining_days = total_days - today    
    days_per = total_days/goal
    on_track = int(today/days_per)
    rate = current/today
    percent_completed = current/goal
    projected_final = int(rate * total_days)
    actual_current_delta = int(math.floor(current)) - on_track
    ahead = 'ahead' if actual_current_delta >= 0 else 'behind'
    projected_finish_day = int(math.ceil(goal/rate))
    projected_finish_date = (
        datetime.date(datetime.date.today().year, 1, 1)
        + datetime.timedelta(projected_finish_day)
    )
    days_til_projected = projected_finish_day - today

    print("Goodreads Reading Challenge Stats Thingy")
    print()
    print(
        f"You have read {int(math.floor(current))} out of your pledge of {goal} books.\n"
        f"Your Reading Challenge is {percent_completed:.1%} complete, "
        f"{actual_current_delta} books {ahead} of a scheduled {on_track}.\n"
        f"At the current rate of {rate:.2} books/day, you are projected to "
        f"finish your challenge\non {projected_finish_date:%B %d, %Y} "
        f"({days_til_projected} days from now), and read {projected_final} "
        "books by the end of the year!"
    )
    return

if __name__ == "__main__":
    sys.exit(main(sys.argv))