#!/usr/bin/env python
# -*- encoding: utf-8; py-indent-offset: 4 -*-

# Author: Sebastian Mark
# CC-BY-SA (https://creativecommons.org/licenses/by-sa/4.0/deed.de)

# pylint: disable=missing-module-docstring,missing-function-docstring,consider-using-f-string

import re


def readinput():
    with open("input", "r", encoding="utf-8") as file:
        lines = [line.rstrip("\n") for line in file.readlines()]
    return lines


def find_numbers(lines: list) -> set:
    # create a set of [(y,x,number),(y,x,number)]
    numbers = set()
    for y, line in enumerate(lines):
        matches = re.finditer(r"\d+", line)
        for match in matches:
            x = match.start()
            numbers.add((y, x, match.group()))
    return numbers


def check_partnumber(lines: list, starty: int, startx: int, partnumber: str) -> bool:
    directions = [
        (-1, 0),  # Up
        (-1, 1),  # Up-right
        (0, 1),  # Right
        (1, 1),  # Down-right
        (1, 0),  # Down
        (1, -1),  # Down-left
        (0, -1),  # Left
        (-1, -1),  # Up-left
    ]

    width = len(lines[0])
    height = len(lines)

    for charpos in range(
        startx, startx + len(partnumber)
    ):  # for all numbers in the partnumber
        for dy, dx in directions:  # check all directions
            nxty, nxtx = starty + dy, charpos + dx  # new checkposition
            if 0 <= nxtx < width and 0 <= nxty < height:  # validate borders
                if lines[nxty][nxtx] not in "0123456789.":
                    return True  # found symbol, this is a valid partnumber

    return False


def main():
    lines = readinput()
    numbers = find_numbers(lines)

    # part 1
    count = 0
    for y, x, number in numbers:
        if check_partnumber(lines, y, x, number):
            count += int(number)
    print("Sum of partnumbers: %d" % count)


if __name__ == "__main__":
    main()