day-1.py

#!/usr/bin/env python

"""Advent of Code Programming Puzzles

2019 Edition - Day One
Puzzle Solution in Python
"""

import argparse
import logging
import os
import sys


EXIT_SUCCESS = 0
LOG_FORMAT = ('%(asctime)s - %(levelname)s - %(module)s - '
              '%(funcName)s - %(message)s')

log = logging.getLogger(__name__)


def load_contents(filename: str) -> list[int]:
    """Load contents from the given file

    :param filename: filename as string
    :return: list of integers
    """
    contents = list(map(int, open(filename).read().strip().split(os.linesep)))
    log.info(f'Loaded {len(contents)} values from file {filename}')
    return contents


# Puzzle Solving Methods -------------------------------------------------------


def compute_required_fuel(mass: int) -> int:
    """Compute required fuel from a mass

    :param mass: mass value
    :return: required fuel quantity
    """
    required_fuel = mass // 3 - 2
    return required_fuel


def solve(contents: list[int]):
    """Solve part one of the puzzle

    :param contents: list of integers
    :return: answer for the part one of the puzzle
    """
    mass_values = contents
    fuel_values = [compute_required_fuel(mass) for mass in mass_values]
    answer = sum(fuel_values)
    return answer


def compute_recursive_required_fuel(mass: int) -> int:
    """Compute required fuel from a mass taking the weight of fuel into account

    :param mass: mass value
    :return: total required fuel quantity
    """
    fuel = compute_required_fuel(mass=mass)
    if fuel <= 0:
        return 0
    extra_fuel = compute_recursive_required_fuel(mass=fuel)
    total_fuel = fuel + extra_fuel
    return total_fuel


def solve_part_two(contents: list[int]):
    """Solve part two of the puzzle

    :param contents: list of integers
    :return: answer for the part one of the puzzle
    """
    mass_values = contents
    fuel_values = [compute_recursive_required_fuel(mass) for mass in mass_values]
    answer = sum(fuel_values)
    return answer


# Support Methods --------------------------------------------------------------

def configure_logger(verbose: bool):
    """Configure logging

    :param verbose: display debug and info messages
    :return: nothing
    """
    logger = logging.getLogger()
    logger.handlers = []
    stdout = logging.StreamHandler(sys.stdout)
    stdout.setLevel(level=logging.WARNING)
    stdout.setFormatter(logging.Formatter(LOG_FORMAT))
    logger.addHandler(stdout)
    if verbose:
        stdout.setLevel(level=logging.DEBUG)
        logger.setLevel(level=logging.DEBUG)


def parse_arguments() -> argparse.Namespace:
    """Parse arguments provided by the command-line

    :return: list of decoded arguments
    """
    parser = argparse.ArgumentParser(description=__doc__)
    pa = parser.add_argument
    pa('filename', type=str, help='input contents filename')
    pa('-p', '--part', type=int, help='solve only the given part')
    pa('-v', '--verbose', action='store_true', help='print extra messages')
    arguments = parser.parse_args()
    return arguments


def main() -> int:
    """Script main method

    :return: script exit code returned to the shell
    """
    args = parse_arguments()
    configure_logger(verbose=args.verbose)
    log.debug(f'Arguments: {args}')
    contents = load_contents(filename=args.filename)
    compute_part_one = not args.part or 1 == args.part
    compute_part_two = not args.part or 2 == args.part
    if compute_part_one:
        answer = solve(contents=contents)
        print(answer)
    if compute_part_two:
        answer = solve_part_two(contents=contents)
        print(answer)
    return EXIT_SUCCESS


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