from scripted import fixture_board

from dojo.board import Board, Pos, edge
from dojo.movement import walks

BOARD = fixture_board()


def test_walks_have_exact_length_and_never_repeat_a_square() -> None:
    start = Pos(4, 4)

    paths = walks(BOARD, start, 4, {start}, can_enter_dojo=False)

    assert paths
    for path in paths:
        assert len(path) == 4
        assert len({start, *path}) == 5
        for a, b in zip((start, *path), path, strict=False):
            assert b in set(BOARD.neighbours(a))


def test_visited_squares_are_never_entered() -> None:
    start = Pos(4, 4)
    visited = {start, Pos(4, 5), Pos(3, 4)}

    paths = walks(BOARD, start, 3, visited, can_enter_dojo=False)

    assert all(not visited & set(path) for path in paths)


def test_dojo_is_a_wall_unless_it_may_be_entered() -> None:
    start = Pos(4, 7)

    closed = walks(BOARD, start, 5, {start}, can_enter_dojo=False)
    opened = walks(BOARD, start, 5, {start}, can_enter_dojo=True)

    assert not any(BOARD.dojo & set(path) for path in closed)
    into_dojo = [path for path in opened if path[-1] in BOARD.dojo]
    assert (Pos(5, 7), Pos(6, 7)) in into_dojo
    assert all(cell not in BOARD.dojo for path in into_dojo for cell in path[:-1])
    assert set(opened) - set(into_dojo) == set(closed)


def test_boxed_in_pawn_moves_as_far_as_possible() -> None:
    walls = frozenset(edge(Pos(0, c), Pos(1, c)) for c in range(3))
    corridor = Board(cells=((".",) * 3,) * 3, walls=walls, tunnels={})

    paths = walks(corridor, Pos(0, 0), 5, {Pos(0, 0)}, can_enter_dojo=False)

    assert paths == [(Pos(0, 1), Pos(0, 2))]