from typing import Iterator

test_input = """
MMMSXXMASM
MSAMXMSMSA
AMXSXMAAMM
MSAMASMSMX
XMASAMXAMM
XXAMMXXAMA
SMSMSASXSS
SAXAMASAAA
MAMMMXMMMM
MXMXAXMASX
""".strip()

test_solution_p1 = 18
test_solution_p2 = 9


def solve_p1(puzzle_input: str) -> int:
    word_grid = _parse_world_grid(puzzle_input)
    return sum(_count_xmas(line) for line in _scan_word_grid(word_grid))


def solve_p2(puzzle_input: str) -> int:
    word_grid = _parse_world_grid(puzzle_input)
    squares = _three_squares(word_grid)
    return sum(1 for square in squares if _has_cross_mas(square))


def _parse_world_grid(puzzle_input: str) -> tuple[tuple[str, ...], ...]:
    return tuple(tuple(row) for row in puzzle_input.splitlines())


def _scan_word_grid(
    char_grid: tuple[tuple[str, ...], ...]
) -> Iterator[tuple[str, ...]]:
    yield from (row for row in char_grid)
    yield from (tuple(col) for col in zip(*char_grid))
    yield from (
        _diagonal(char_grid, i) for i in range(-len(char_grid) + 1, len(char_grid[0]))
    )
    yield from (
        _diagonal(tuple(reversed(char_grid)), i)
        for i in range(-len(char_grid) + 1, len(char_grid[0]))
    )


def _diagonal(grid: tuple[tuple[str, ...], ...], offset=0) -> tuple[str, ...]:
    return tuple(
        grid[i][i + offset] for i in range(len(grid)) if 0 <= i + offset < len(grid)
    )


def _count_xmas(line: tuple[str, ...]) -> int:
    return sum(
        1
        for i in range(len(line) - 3)
        if line[i : i + 4] in (("X", "M", "A", "S"), ("S", "A", "M", "X"))
    )


ThreeSquare = tuple[tuple[str, str, str], tuple[str, str, str], tuple[str, str, str]]


def _three_squares(word_grid: tuple[tuple[str, ...], ...]) -> Iterator[ThreeSquare]:
    yield from (
        (
            word_grid[i][j : j + 3],
            word_grid[i + 1][j : j + 3],
            word_grid[i + 2][j : j + 3],
        )
        for i in range(len(word_grid) - 2)
        for j in range(len(word_grid[0]) - 2)
    )


def _has_cross_mas(square: ThreeSquare):
    diag_1 = (square[0][0], square[1][1], square[2][2])
    diag_2 = (square[0][2], square[1][1], square[2][0])
    return (diag_1 == ("M", "A", "S") or diag_1 == ("S", "A", "M")) and (
        diag_2 == ("M", "A", "S") or diag_2 == ("S", "A", "M")
    )