"""Tests for corner-rule line of effect and cover (los.py).

Geometry convention: a line is blocked when its relative interior touches a
blocking square (interior, border, or vertex); lines that merely start or end
on a blocking square's vertex do not count as passing through it.
"""

from __future__ import annotations

from pf1e_simulator.grid import Grid
from pf1e_simulator.los import has_cover, has_line_of_effect
from pf1e_simulator.map import MapSpec, TerrainType


def make_grid(rows: list[str]) -> Grid:
    legend = {
        "#": TerrainType(type="wall", move_cost=None, blocks_los=True),
        ".": TerrainType(type="floor", move_cost=1),
        "T": TerrainType(type="rubble", move_cost=2),
        "C": TerrainType(type="pillar", move_cost=None, cover=True),
    }
    spec = MapSpec(name="test", terrain=tuple(rows), legend=legend)
    return Grid.from_spec(spec)


def test_los_open_field() -> None:
    grid = make_grid(["...", "...", "..."])
    assert has_line_of_effect(grid, (0, 0), (2, 2)) is True


def test_los_same_square() -> None:
    grid = make_grid(["."])
    assert has_line_of_effect(grid, (0, 0), (0, 0)) is True


def test_los_blocked_by_wall_between() -> None:
    grid = make_grid([".#.", "..."])
    assert has_line_of_effect(grid, (0, 0), (0, 2)) is False


def test_los_through_doorway_gap() -> None:
    grid = make_grid(["##.##", "##.##"])
    assert has_line_of_effect(grid, (0, 2), (1, 2)) is True


def test_los_pinched_vertex_stays_open() -> None:
    grid = make_grid([".#.", "#.."])
    assert has_line_of_effect(grid, (0, 0), (1, 1)) is True


def test_los_blocked_past_wall_line() -> None:
    grid = make_grid(["...#.", "....."])
    assert has_line_of_effect(grid, (0, 0), (0, 4)) is False


def test_cover_open_field() -> None:
    grid = make_grid([".....", "....."])
    assert has_cover(grid, (0, 0), (0, 4), ranged=True) is False


def test_cover_pillar_between() -> None:
    grid = make_grid([".....", "..C..", "....."])
    assert has_cover(grid, (1, 0), (1, 4), ranged=True) is True


def test_no_cover_when_pillar_off_axis() -> None:
    grid = make_grid(["..C..", "....."])
    assert has_cover(grid, (1, 0), (1, 4), ranged=True) is False


def test_no_cover_adjacent_with_wall_behind_target() -> None:
    grid = make_grid(["..#"])
    assert has_cover(grid, (0, 0), (0, 1), ranged=True) is False


def test_cover_diagonal_past_wall_vertex() -> None:
    grid = make_grid([".#.", "#.."])
    assert has_cover(grid, (0, 0), (1, 1), ranged=True) is True


def test_cover_melee_uses_same_corner_rule_in_phase0() -> None:
    grid = make_grid([".#.", "#.."])
    assert has_cover(grid, (0, 0), (1, 1), ranged=False) is True
    open_grid = make_grid(["...", "..."])
    assert has_cover(open_grid, (0, 0), (1, 1), ranged=False) is False


def test_cover_same_square_is_false() -> None:
    grid = make_grid(["."])
    assert has_cover(grid, (0, 0), (0, 0), ranged=True) is False


def test_soft_cover_creature_between_grants_cover() -> None:
    """A creature between shooter and target grants cover on ranged attacks."""
    grid = make_grid([".....", ".....", "....."])
    occupied = frozenset({(1, 2)})
    assert has_cover(grid, (1, 0), (1, 4), ranged=True, occupied=occupied) is True


def test_soft_cover_melee_ignores_creatures() -> None:
    """Melee attacks ignore creatures for soft cover (CRB: ranged only)."""
    grid = make_grid([".....", ".....", "....."])
    occupied = frozenset({(1, 2)})
    assert has_cover(grid, (1, 0), (1, 4), ranged=False, occupied=occupied) is False


def test_soft_cover_creature_behind_target_ignored() -> None:
    """A creature behind the target does not grant cover."""
    grid = make_grid(["......", "......"])
    occupied = frozenset({(1, 5)})
    assert has_cover(grid, (1, 0), (1, 4), ranged=True, occupied=occupied) is False


def test_soft_cover_creature_off_axis_ignored() -> None:
    """A creature off the attack line does not grant cover."""
    grid = make_grid([".....", "....."])
    occupied = frozenset({(0, 2)})
    assert has_cover(grid, (1, 0), (1, 4), ranged=True, occupied=occupied) is False