#!/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.strip("\n") for line in file.readlines()]
    return lines


def get_antinodes_for_pair(city: list, pos: tuple, twin: tuple, part: int) -> set:
    width = len(city[0])
    height = len(city)

    antinodes_for_pair = set()

    # distance between pairs
    dy = pos[0] - twin[0]
    dx = pos[1] - twin[1]

    # add antinode(s) above upper antenna
    nxty = pos[0] + dy
    nxtx = pos[1] + dx
    while 0 <= nxty < height and 0 <= nxtx < width:
        antinodes_for_pair.add((nxty, nxtx))
        if part == 1:
            break
        nxty += dy
        nxtx += dx

    # add antinode(s) below lower antenna
    nxty = twin[0] - dy
    nxtx = twin[1] - dx
    while 0 <= nxty < height and 0 <= nxtx < width:
        antinodes_for_pair.add((nxty, nxtx))
        if part == 1:
            break
        nxty -= dy
        nxtx -= dx

    return antinodes_for_pair


def get_antinodes_for_freq(city: list, freq: str, pos: tuple, part: int) -> set:
    starty = pos[0]
    antinodes_for_freq = set()

    # search downwards for twins
    twins = []
    if starty <= len(city):
        for y in range(starty + 1, len(city)):
            x = city[y].find(freq)
            if x >= 0:
                twins.append((y, x))

    for twin in twins:
        antinodes_for_freq |= get_antinodes_for_pair(city, pos, twin, part)

    return antinodes_for_freq


def get_antinodes(city: list, part: int) -> set:
    antinodes = set()

    # serch city for antennas
    for y, street in enumerate(city):
        antennas = re.finditer(r"([a-zA-Z0-9])", street)
        for antenna in antennas:
            freq = antenna.group()
            pos = (y, antenna.start())
            antinodes |= get_antinodes_for_freq(city, freq, pos, part)
            if part == 2:
                antinodes.add(pos)

    return antinodes


def main():
    city = readinput()

    for part in [1, 2]:
        antinodes = get_antinodes(city, part)
        print("Unique antinodes (part%d): %d" % (part, len(antinodes)))


if __name__ == "__main__":
    main()