from pathlib import Path

import pytest

from engine.character import Character
from engine.defs import DefRegistry
from engine.entity import EntityPosition
from engine.map_loader import MapLoader
from engine.tile import TileLayerInstance
from engine.world import World
from resources.logic.steering import advance_all_ship_rotations, advance_ship_rotation, at_helm, try_steer_ship, try_turn_ship

DEFS_DIR = Path(__file__).resolve().parent.parent / "resources" / "defs"


@pytest.fixture()
def registry():
    return DefRegistry.load(DEFS_DIR)


def make_human(registry, **kwargs) -> Character:
    return Character(species_id="human", default_body_parts=registry.new_default_body_parts("human"), **kwargs)


def build_demo_world(registry) -> World:
    loader = MapLoader(DEFS_DIR / "maps")
    demo_world = loader.load("demo_world.json")
    ship = demo_world.embeddings[0].child_map
    world = World(registry=registry)
    world.add_map(demo_world)
    world.add_map(ship)
    return world


def test_at_helm_true_when_standing_on_the_helm_tile(registry):
    world = build_demo_world(registry)
    sailor = make_human(registry, position=EntityPosition("ship_small", 2, 1, 0))
    embedding = at_helm(sailor, world)
    assert embedding is not None
    assert embedding.child_map.map_id == "ship_small"


def test_at_helm_none_elsewhere_on_the_ship(registry):
    world = build_demo_world(registry)
    sailor = make_human(registry, position=EntityPosition("ship_small", 1, 1, 0))
    assert at_helm(sailor, world) is None


def test_at_helm_none_when_not_aboard_an_embedded_map(registry):
    world = build_demo_world(registry)
    person = make_human(registry, position=EntityPosition("demo_world", 1, 1, 0))
    assert at_helm(person, world) is None


def test_steering_moves_the_ship_and_leaves_aboard_entities_local_position_untouched(registry):
    world = build_demo_world(registry)
    ship = world.maps["ship_small"]
    embedding = ship.parent_embedding
    original_anchor = embedding.anchor

    helmsman = make_human(registry, position=EntityPosition("ship_small", 2, 1, 0))
    passenger = make_human(registry, position=EntityPosition("ship_small", 1, 1, 0))

    assert try_steer_ship(helmsman, world, 0, 1, 0) is True
    assert embedding.anchor == (original_anchor[0], original_anchor[1] + 1, original_anchor[2])
    # nobody aboard needed to move - their local coordinates are exactly as before
    assert (helmsman.position.x, helmsman.position.y) == (2, 1)
    assert (passenger.position.x, passenger.position.y) == (1, 1)


def test_steering_fails_if_destination_runs_into_something_unwalkable(registry):
    world = build_demo_world(registry)
    parent = world.maps["demo_world"]
    # ship's footprint is x:6-9, y:6-8; moving west by 1 would occupy x:5-8, y:6-8 -
    # put a wall right in that path
    parent.get_tile(5, 7, 0).room = TileLayerInstance("wood_wall")

    helmsman = make_human(registry, position=EntityPosition("ship_small", 2, 1, 0))
    embedding = world.maps["ship_small"].parent_embedding
    before = embedding.anchor
    assert try_steer_ship(helmsman, world, -1, 0, 0) is False
    assert embedding.anchor == before


def test_steering_fails_off_the_parent_map_edge(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    embedding.move_to((0, 0, 0))  # right at the parent's edge

    helmsman = make_human(registry, position=EntityPosition("ship_small", 2, 1, 0))
    assert try_steer_ship(helmsman, world, -1, 0, 0) is False


def test_turning_the_ship_sets_desired_rotation_but_not_the_actual_one_yet(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    helmsman = make_human(registry, position=EntityPosition("ship_small", 2, 1, 0))

    assert try_turn_ship(helmsman, world, 1) is True
    assert embedding.desired_rotation == 1
    assert embedding.rotation == 0  # doesn't snap - advance_ship_rotation steps it there


def test_repeated_turn_commands_stack_the_desired_rotation(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    helmsman = make_human(registry, position=EntityPosition("ship_small", 2, 1, 0))

    try_turn_ship(helmsman, world, 1)
    try_turn_ship(helmsman, world, 1)
    assert embedding.desired_rotation == 2


def test_advance_ship_rotation_steps_one_quarter_turn_at_a_time(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    helmsman = make_human(registry, position=EntityPosition("ship_small", 2, 1, 0))
    embedding.max_rotation_speed = 90.0  # 1 quarter-turn/second

    try_turn_ship(helmsman, world, 2)  # desired_rotation = 2, two steps needed
    assert advance_ship_rotation(embedding, world, now=0.0) is True
    assert embedding.rotation == 1
    # not enough time has passed yet for the second step
    assert advance_ship_rotation(embedding, world, now=0.5) is False
    assert embedding.rotation == 1
    assert advance_ship_rotation(embedding, world, now=1.0) is True
    assert embedding.rotation == 2


def test_advance_ship_rotation_takes_the_shorter_direction(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    embedding.desired_rotation = 3
    advance_ship_rotation(embedding, world, now=0.0)
    assert embedding.rotation == 3  # one counter-clockwise step, not three clockwise ones


def test_advance_ship_rotation_no_op_when_already_at_desired(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    assert advance_ship_rotation(embedding, world, now=0.0) is False
    assert embedding.rotation == 0


def test_slower_max_rotation_speed_takes_longer_per_step(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    embedding.max_rotation_speed = 30.0  # 3 seconds per quarter-turn
    embedding.desired_rotation = 1

    assert advance_ship_rotation(embedding, world, now=0.0) is True
    assert embedding.rotation == 1
    assert embedding.rotation_ready_at == pytest.approx(3.0)


def test_advance_ship_rotation_pauses_if_blocked_but_keeps_desired_heading(registry):
    world = build_demo_world(registry)
    parent = world.maps["demo_world"]
    ship = world.maps["ship_small"]
    embedding = ship.parent_embedding
    # block the intermediate rotated footprint so the step can't complete
    for x in range(parent.width):
        for y in range(parent.height):
            parent.get_tile(x, y, 0).room = TileLayerInstance("wood_wall")
    embedding.desired_rotation = 1

    assert advance_ship_rotation(embedding, world, now=0.0) is False
    assert embedding.rotation == 0
    assert embedding.desired_rotation == 1  # still wants to get there, just blocked for now


def test_advance_all_ship_rotations_advances_every_embedding(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    embedding.desired_rotation = 1
    advance_all_ship_rotations(world, now=0.0)
    assert embedding.rotation == 1


def test_non_helmsman_cannot_steer(registry):
    world = build_demo_world(registry)
    embedding = world.maps["ship_small"].parent_embedding
    before = embedding.anchor
    bystander = make_human(registry, position=EntityPosition("ship_small", 1, 1, 0))
    assert try_steer_ship(bystander, world, 1, 0, 0) is False
    assert embedding.anchor == before