# --- Day 3: Perfectly Spherical Houses in a Vacuum ---

# Santa is delivering presents to an infinite two-dimensional grid of houses.

# He begins by delivering a present to the house at his starting location, and
# then an elf at the North Pole calls him via radio and tells him where to move
# next. Moves are always exactly one house to the north (^), south (v), east
# (>), or west (<). After each move, he delivers another present to the house
# at his new location.

# However, the elf back at the north pole has had a little too much eggnog, and
# so his directions are a little off, and Santa ends up visiting some houses
# more than once. How many houses receive at least one present?

# For example:

#     > delivers presents to 2 houses: one at the starting location, and one to
# the east.
#     ^>v< delivers presents to 4 houses in a square, including twice to the
# house at his starting/ending location.
#     ^v^v^v^v^v delivers a bunch of presents to some very lucky children at
# only 2 houses.

from typing import Tuple

with open("files/P3.txt") as f:
    moves = [line for line in f.read().strip().split()][0]


def move_up(pos: Tuple[int, int]) -> Tuple[int, int]:
    return pos[0], pos[1] + 1


def move_down(pos: Tuple[int, int]) -> Tuple[int, int]:
    return pos[0], pos[1] - 1


def move_left(pos: Tuple[int, int]) -> Tuple[int, int]:
    return pos[0] - 1, pos[1]


def move_right(pos: Tuple[int, int]) -> Tuple[int, int]:
    return pos[0] + 1, pos[1]


def part_1() -> None:
    pos = [(0, 0)]
    for move in moves:
        if move == "^":
            pos.append(move_up(pos[-1]))
        elif move == "v":
            pos.append(move_down(pos[-1]))
        elif move == "<":
            pos.append(move_left(pos[-1]))
        elif move == ">":
            pos.append(move_right(pos[-1]))

    print(f"{len(set(pos))} houses receive at least one present")


if __name__ == "__main__":
    part_1()